Sample records for groups cloud modeling

  1. Cloud Tracking in Cloud-Resolving Models

    E-Print Network [OSTI]

    Plant, Robert

    Cloud Tracking in Cloud-Resolving Models RMetS Conference 4th September 2007 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations What is the distribution of cloud lifetimes? What factors determine the lifetime of an individual

  2. DIRSIG Cloud Modeling Capabilities; A Parametric Study

    E-Print Network [OSTI]

    Salvaggio, Carl

    1 DIRSIG Cloud Modeling Capabilities; A Parametric Study Kristen Powers powers:................................................................................................................... 13 Calculation of Sensor Reaching Radiance Truth Values for Cloudless & Stratus Cloud Scenes and Atmospheric Database Creation for Stratus Cloud Scene & Calculation of Associated Sensor Reaching Radiance

  3. CloudAnalyst: A CloudSim-based Visual Modeller for Analysing Cloud Computing Environments and Applications

    E-Print Network [OSTI]

    Calheiros, Rodrigo N.

    CloudAnalyst: A CloudSim-based Visual Modeller for Analysing Cloud Computing Environments and Applications Bhathiya Wickremasinghe1 , Rodrigo N. Calheiros2 , and Rajkumar Buyya1 1 The Cloud Computing and Distributed Systems (CLOUDS) Laboratory Department of Computer Science and Software Engineering The University

  4. Modeling Incoherent Electron Cloud Effects

    E-Print Network [OSTI]

    Benedetto, E.

    2008-01-01T23:59:59.000Z

    electron-cloud effects and synchrotron radiation can lead toelectron-cloud effects and synchrotron radiation can lead tocloud phenomena in positrons storage rings the effect of syn- chrotron radiation

  5. Modelling Cloud Computing Infrastructure Marianne Hickey and Maher Rahmouni,

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modelling Cloud Computing Infrastructure Marianne Hickey and Maher Rahmouni, HP Labs, Long Down, and shared vocabularies. Keywords: Modelling, Cloud Computing, RDF, Ontology, Rules, Validation 1 Introduction There is currently a shift towards cloud computing, which changes the model of provision

  6. Free-Floating HI Clouds in the M 81 Group

    E-Print Network [OSTI]

    Elias Brinks; Fabian Walter; Evan D. Skillman

    2007-08-21T23:59:59.000Z

    Recent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~1e5 Msol) HI clouds with no obvious optical counterparts. We have searched 10 fields in the M81 group totalling 2.2 square degree, both targeting known dwarf spheroidal galaxies and blank fields around the central triplet. Our observations show that the new population of low-mass HI clouds appears to be confined to a region toward the South-East of the central triplet (at distances of ~100 kpc from M 81). Possible explanations for these free-floating HI clouds are that they are related to the dSphs found to the South-East of M 81, that they belong to the galaxies of the M 81 triplet (equivalent to HVCs), that they are of primordial nature and provide fresh, unenriched material falling into the M 81 group, or that they are tidal debris from the 3-body interaction involving M 81-M 82-NGC 3077. Based on circumstantial evidence, we currently favour the latter explanation.

  7. Cloud Tracking in Cloud-Resolving Models R. S. Plant1

    E-Print Network [OSTI]

    Plant, Robert

    Cloud Tracking in Cloud-Resolving Models R. S. Plant1 1 Department of Meteorology, University. INTRODUCTION In recent years Cloud Resolving Models (CRMs) have become an increasingly important tool for CRM data, which allows one to investigate statistical prop- erties of the lifecycles of the "clouds

  8. Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing applications

    E-Print Network [OSTI]

    Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing broadening and drizzle growth in shallow liquid clouds remain not well understood. Detailed, cloudscale. Profiling, millimeterwavelength (cloud) radars can provide such observations. In particular, the first three

  9. A 3D STOCHASTIC CLOUD MODEL FOR INVESTIGATING THE RADIATIVE PROPERTIES OF INHOMOGENEOUS CIRRUS CLOUDS

    E-Print Network [OSTI]

    Hogan, Robin

    A 3D STOCHASTIC CLOUD MODEL FOR INVESTIGATING THE RADIATIVE PROPERTIES OF INHOMOGENEOUS CIRRUS, Berkshire, United Kingdom 1 INTRODUCTION The importance of ice clouds on the earth's radiation budget for quantifying this effect, and several such models exist for boundary layer clouds, such as those of Cahalan et

  10. Towards the Next Generation of Model-Driven Cloud Platforms

    E-Print Network [OSTI]

    Muńoz, Francesc

    Towards the Next Generation of Model-Driven Cloud Platforms Javier Esparza-Peidro, Francesc D. Mu~noz-Esco of Model-Driven Cloud Platforms Javier Esparza-Peidro, Francesc D. Mu~noz-Esco´i Institut Universitari Mixt

  11. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during

    E-Print Network [OSTI]

    Zuidema, Paquita

    /crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterizationIntercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud

  12. A Community Atmosphere Model with Superparameterized Clouds

    SciTech Connect (OSTI)

    Randall, David; Branson, Mark; Wang, Minghuai; Ghan, Steven J.; Craig, Cheryl; Gettelman, A.; Edwards, Jim

    2013-06-18T23:59:59.000Z

    In 1999, National Center for Atmospheric Research (NCAR) scientists Wojciech Grabowski and Piotr Smolarkiewicz created a "multiscale" atmospheric model in which the physical processes associated with clouds were represented by running a simple high-resolution model within each grid column of a lowresolution global model. In idealized experiments, they found that the multiscale model produced promising simulations of organized tropical convection, which other models had struggled to produce. Inspired by their results, Colorado State University (CSU) scientists Marat Khairoutdinov and David Randall created a multiscale version of the Community Atmosphere Model (CAM). They removed the cloud parameterizations of the CAM, and replaced them with Khairoutdinov's high-resolution cloud model. They dubbed the embedded cloud model a "super-parameterization," and the modified CAM is now called the "SP-CAM." Over the next several years, many scientists, from many institutions, have explored the ability of the SP-CAM to simulate tropical weather systems, the day-night changes of precipitation, the Asian and African monsoons, and a number of other climate processes. Cristiana Stan of the Center for Ocean-Land-Atmosphere Interactions found that the SP-CAM gives improved results when coupled to an ocean model, and follow-on studies have explored the SP-CAM's utility when used as the atmospheric component of the Community Earth System Model. Much of this research has been performed under the auspices of the Center for Multiscale Modeling of Atmospheric Processes, a National Science Foundation (NSF) Science and Technology Center for which the lead institution is CSU.

  13. Towards a New Execution Model for HPC Clouds Thomas Sterling

    E-Print Network [OSTI]

    Lumsdaine, Andrew

    Towards a New Execution Model for HPC Clouds Thomas Sterling Center for Research in Extreme Scale an alternative paradigm for bringing Clouds more closely aligned to Science, Technology, Engineering Execution Model for HPC Clouds Thomas Sterling 1. Introduction Even as HPC is transiting the pan

  14. Aerosols and clouds in chemical transport models and climate models.

    SciTech Connect (OSTI)

    Lohmann,U.; Schwartz, S. E.

    2008-03-02T23:59:59.000Z

    Clouds exert major influences on both shortwave and longwave radiation as well as on the hydrological cycle. Accurate representation of clouds in climate models is a major unsolved problem because of high sensitivity of radiation and hydrology to cloud properties and processes, incomplete understanding of these processes, and the wide range of length scales over which these processes occur. Small changes in the amount, altitude, physical thickness, and/or microphysical properties of clouds due to human influences can exert changes in Earth's radiation budget that are comparable to the radiative forcing by anthropogenic greenhouse gases, thus either partly offsetting or enhancing the warming due to these gases. Because clouds form on aerosol particles, changes in the amount and/or composition of aerosols affect clouds in a variety of ways. The forcing of the radiation balance due to aerosol-cloud interactions (indirect aerosol effect) has large uncertainties because a variety of important processes are not well understood precluding their accurate representation in models.

  15. Intercomparison of cloud model simulations of Arctic mixed-phase boundary layer clouds observed during SHEBA/FIRE-ACE

    SciTech Connect (OSTI)

    Morrison, H.; Zuidema, Paquita; Ackerman, Andrew; Avramov, Alexander; de Boer, Gijs; Fan, Jiwen; Fridlind, Ann; Hashino, Tempei; Harrington, Jerry Y.; Luo, Yali; Ovchinnikov, Mikhail; Shipway, Ben

    2011-06-16T23:59:59.000Z

    An intercomparison of six cloud-resolving and large-eddy simulation models is presented. This case study is based on observations of a persistent mixed-phase boundary layer cloud gathered on 7 May, 1998 from the Surface Heat Budget of Arctic Ocean (SHEBA) and First ISCCP Regional Experiment - Arctic Cloud Experiment (FIRE-ACE). Ice nucleation is constrained in the simulations in a way that holds the ice crystal concentration approximately fixed, with two sets of sensitivity runs in addition to the baseline simulations utilizing different specified ice nucleus (IN) concentrations. All of the baseline and sensitivity simulations group into two distinct quasi-steady states associated with either persistent mixed-phase clouds or all-ice clouds after the first few hours of integration, implying the existence of multiple equilibria. These two states are associated with distinctly different microphysical, thermodynamic, and radiative characteristics. Most but not all of the models produce a persistent mixed-phase cloud qualitatively similar to observations using the baseline IN/crystal concentration, while small increases in the IN/crystal concentration generally lead to rapid glaciation and conversion to the all-ice state. Budget analysis indicates that larger ice deposition rates associated with increased IN/crystal concentrations have a limited direct impact on dissipation of liquid in these simulations. However, the impact of increased ice deposition is greatly enhanced by several interaction pathways that lead to an increased surface precipitation flux, weaker cloud top radiative cooling and cloud dynamics, and reduced vertical mixing, promoting rapid glaciation of the mixed-phase cloud for deposition rates in the cloud layer greater than about 1-2x10-5 g kg-1 s-1. These results indicate the critical importance of precipitation-radiative-dynamical interactions in simulating cloud phase, which have been neglected in previous fixed-dynamical parcel studies of the cloud phase parameter space. Large sensitivity to the IN/crystal concentration also suggests the need for improved understanding of ice nucleation and its parameterization in models.

  16. Decision Model for Cloud Computing

    E-Print Network [OSTI]

    Kondo, Derrick

    with different pricing models for cost-cutting, resource-hungry users. Second, prices can differ dynamically (as Grenoble, France 1 #12;Trade-offs Supercomputers Performance Reliability Cost ($) low high high high Instances · "Spot" instance price varies dynamically · Spot instance provided when user's bid is greater

  17. Modeling, Characterizing, and Enhancing User Experience in Cloud Mobile Rendering

    E-Print Network [OSTI]

    California at San Diego, University of

    Modeling, Characterizing, and Enhancing User Experience in Cloud Mobile Rendering Yao Liu, Shaoxuan of California, San Diego {yal019, shaoxuan, dey}@ece.ucsd.edu Abstract--Cloud Mobile Rendering (CMR), where compute intensive rendering is performed on cloud servers instead of on mobile devices, can be a promising

  18. Latency based Dynamic Grouping aware Cloud Sheheryar Malik,

    E-Print Network [OSTI]

    Boyer, Edmond

    - Sophia Antipolis Sophia Antipolis, France sheheryar.malik@inria.fr Fabrice Huet Research Team OASIS INRIA - Sophia Antipolis Sophia Antipolis, France fabrice.huet@inria.fr Denis Caromel Research Team OASIS INRIA - Sophia Antipolis Sophia Antipolis, France denis.caromel@inria.fr Abstract--In a multi-cloud environment

  19. Disruptive technology business models in cloud computing

    E-Print Network [OSTI]

    Krikos, Alexis Christopher

    2010-01-01T23:59:59.000Z

    Cloud computing, a term whose origins have been in existence for more than a decade, has come into fruition due to technological capabilities and marketplace demands. Cloud computing can be defined as a scalable and flexible ...

  20. Intercomparison of the Cloud Water Phase among Global Climate Models

    SciTech Connect (OSTI)

    Komurcu, Muge; Storelvmo, Trude; Tan, Ivy; Lohmann, U.; Yun, Yuxing; Penner, Joyce E.; Wang, Yong; Liu, Xiaohong; Takemura, T.

    2014-03-27T23:59:59.000Z

    Mixed-phase clouds (clouds that consist of both cloud droplets and ice crystals) are frequently present in the Earth’s atmosphere and influence the Earth’s energy budget through their radiative properties, which are highly dependent on the cloud water phase. In this study, the phase partitioning of cloud water is compared among six global climate models (GCMs) and with Cloud and Aerosol Lidar with Orthogonal Polarization retrievals. It is found that the GCMs predict vastly different distributions of cloud phase for a given temperature, and none of them are capable of reproducing the spatial distribution or magnitude of the observed phase partitioning. While some GCMs produced liquid water paths comparable to satellite observations, they all failed to preserve sufficient liquid water at mixed-phase cloud temperatures. Our results suggest that validating GCMs using only the vertically integrated water contents could lead to amplified differences in cloud radiative feedback. The sensitivity of the simulated cloud phase in GCMs to the choice of heterogeneous ice nucleation parameterization is also investigated. The response to a change in ice nucleation is quite different for each GCM, and the implementation of the same ice nucleation parameterization in all models does not reduce the spread in simulated phase among GCMs. The results suggest that processes subsequent to ice nucleation are at least as important in determining phase and should be the focus of future studies aimed at understanding and reducing differences among the models.

  1. Model-Driven Cloud Data Storage Juan Castrejn1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of attention, due to a growing interest in the challenges and opportuni- ties associated to the NoSQL movement-level data models, and then rely on transformation procedures to deal with particular cloud storage details modifying their core data models. 1 Introduction Cloud computing represents one of the most promising

  2. Development of advanced cloud parameterizations to examine air quality, cloud properties, and cloud-radiation feedback in mesoscale models

    SciTech Connect (OSTI)

    Lee, In Young

    1993-09-01T23:59:59.000Z

    The distribution of atmospheric pollutants is governed by dynamic processes that create the general conditions for transport and mixing, by microphysical processes that control the evolution of aerosol and cloud particles, and by chemical processes that transform chemical species and form aerosols. Pollutants emitted into the air can undergo homogeneous gas reactions to create a suitable environment for the production by heterogeneous nucleation of embryos composed of a few molecules. The physicochemical properties of preexisting aerosols interact with newly produced embryos to evolve by heteromolecular diffusion and coagulation. Hygroscopic particles wig serve as effective cloud condensation nuclei (CCN), while hydrophobic particles will serve as effective ice-forming nuclei. Clouds form initially by condensation of water vapor on CCN and evolve in a vapor-liquid-solid system by deposition, sublimation, freezing, melting, coagulation, and breakup. Gases and aerosols that enter the clouds undergo aqueous chemical processes and may acidity hydrometer particles. Calculations for solar and longwave radiation fluxes depend on how the respective spectra are modified by absorbers such as H{sub 2}O, CO{sub 2}, O{sub 3}, CH{sub 4}, N{sub 2}O, chlorofruorocarbons, and aerosols. However, the flux calculations are more complicated for cloudy skies, because the cloud optical properties are not well defined. In this paper, key processes such as tropospheric chemistry, cloud microphysics parameterizations, and radiation schemes are reviewed in terms of physicochemical processes occurring, and recommendations are made for the development of advanced modules applicable to mesoscale models.

  3. 3D Atmospheric Radiative Transfer for Cloud System-Resolving Models: Forward Modelling and Observations

    SciTech Connect (OSTI)

    Howard Barker; Jason Cole

    2012-05-17T23:59:59.000Z

    Utilization of cloud-resolving models and multi-dimensional radiative transfer models to investigate the importance of 3D radiation effects on the numerical simulation of cloud fields and their properties.

  4. Statistical Modeling of Spot Instance Prices in Public Cloud Environments

    E-Print Network [OSTI]

    Buyya, Rajkumar

    Statistical Modeling of Spot Instance Prices in Public Cloud Environments Bahman Javadi, Ruppa K resources has introduced many trade-offs between price, per- formance and recently reliability. Amazon's Spot Instances (SIs) create a competitive bidding option for the public Cloud users at lower prices

  5. Hypercentral Constituent Quark Model with a Meson Cloud

    E-Print Network [OSTI]

    D. Y. Chen; Y. B. Dong; M. M. Giannini; E. Santopinto

    2006-11-07T23:59:59.000Z

    The results for the elastic nucleon form factors and the electromagnetic transition amplitudes to the Delta(1232) resonance, obtained with the Hypercentral Constituent Quark Model with the inclusion of a meson cloud correction are briefly presented. The pion cloud effects are explicitly discussed.

  6. The aerosol direct radiative effect (DRE) over clouds is quantified using measured reflectance spectra of UV-absorbing aerosol polluted cloud scenes and modeled reflectance spectra of unpolluted cloud scenes. The cloud reflectance spectra are read from

    E-Print Network [OSTI]

    Graaf, Martin de

    distribution of clouds and aerosols along the white CALIPSO track in Fig.1b is shown in Fig. 2. The distanceThe aerosol direct radiative effect (DRE) over clouds is quantified using measured reflectance spectra of UV-absorbing aerosol polluted cloud scenes and modeled reflectance spectra of unpolluted cloud

  7. Representing Cloud Processing of Aerosol in Numerical Models

    SciTech Connect (OSTI)

    Mechem, D.B.; Kogan, Y.L.

    2005-03-18T23:59:59.000Z

    The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.

  8. A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part II: Single-Column Modeling of Arctic Clouds

    E-Print Network [OSTI]

    Shupe, Matthew

    of the arctic bound- ary layer, the presence of leads (cracks) in the sea ice surface, the persistence of mixed-phaseA New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part- dicted cloud boundaries and total cloud fraction compare reasonably well with observations. Cloud phase

  9. Cirrus clouds in a global climate model with a statistical cirrus cloud scheme

    SciTech Connect (OSTI)

    Wang, Minghuai; Penner, Joyce E.

    2010-06-21T23:59:59.000Z

    A statistical cirrus cloud scheme that accounts for mesoscale temperature perturbations is implemented in a coupled aerosol and atmospheric circulation model to better represent both subgrid-scale supersaturation and cloud formation. This new scheme treats the effects of aerosol on cloud formation and ice freezing in an improved manner, and both homogeneous freezing and heterogeneous freezing are included. The scheme is able to better simulate the observed probability distribution of relative humidity compared to the scheme that was implemented in an older version of the model. Heterogeneous ice nuclei (IN) are shown to decrease the frequency of occurrence of supersaturation, and improve the comparison with observations at 192 hPa. Homogeneous freezing alone can not reproduce observed ice crystal number concentrations at low temperatures (<205 K), but the addition of heterogeneous IN improves the comparison somewhat. Increases in heterogeneous IN affect both high level cirrus clouds and low level liquid clouds. Increases in cirrus clouds lead to a more cloudy and moist lower troposphere with less precipitation, effects which we associate with the decreased convective activity. The change in the net cloud forcing is not very sensitive to the change in ice crystal concentrations, but the change in the net radiative flux at the top of the atmosphere is still large because of changes in water vapor. Changes in the magnitude of the assumed mesoscale temperature perturbations by 25% alter the ice crystal number concentrations and the net radiative fluxes by an amount that is comparable to that from a factor of 10 change in the heterogeneous IN number concentrations. Further improvements on the representation of mesoscale temperature perturbations, heterogeneous IN and the competition between homogeneous freezing and heterogeneous freezing are needed.

  10. Group pyrolysis, ignition, and combustion of a spherical cloud of coal particles

    E-Print Network [OSTI]

    Ryan, William Richard

    1988-01-01T23:59:59.000Z

    , and combustion of pulverized coal. Finally, the relevance of group combustion studies to practical systems is discussed. 2. 1. Grou Combustion and Terminolo Group combustion implies the formation of a common flame around a large number of drops... of the processes involved in practical burners, these studies are useful in the prevention of dust cloud explosions. The experimental apparatus and conditions for conducting pulverized coal ignition studies are described briefly: (1. ) Transport Reactors...

  11. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part II: Multi-layered cloud

    SciTech Connect (OSTI)

    Morrison, H; McCoy, R B; Klein, S A; Xie, S; Luo, Y; Avramov, A; Chen, M; Cole, J; Falk, M; Foster, M; Genio, A D; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; McFarquhar, G; Poellot, M; Shipway, B; Shupe, M; Sud, Y; Turner, D; Veron, D; Walker, G; Wang, Z; Wolf, A; Xu, K; Yang, F; Zhang, G

    2008-02-27T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a deep, multi-layered, mixed-phase cloud system observed during the ARM Mixed-Phase Arctic Cloud Experiment. This cloud system was associated with strong surface turbulent sensible and latent heat fluxes as cold air flowed over the open Arctic Ocean, combined with a low pressure system that supplied moisture at mid-level. The simulations, performed by 13 single-column and 4 cloud-resolving models, generally overestimate the liquid water path and strongly underestimate the ice water path, although there is a large spread among the models. This finding is in contrast with results for the single-layer, low-level mixed-phase stratocumulus case in Part I of this study, as well as previous studies of shallow mixed-phase Arctic clouds, that showed an underprediction of liquid water path. The overestimate of liquid water path and underestimate of ice water path occur primarily when deeper mixed-phase clouds extending into the mid-troposphere were observed. These results suggest important differences in the ability of models to simulate Arctic mixed-phase clouds that are deep and multi-layered versus shallow and single-layered. In general, models with a more sophisticated, two-moment treatment of the cloud microphysics produce a somewhat smaller liquid water path that is closer to observations. The cloud-resolving models tend to produce a larger cloud fraction than the single-column models. The liquid water path and especially the cloud fraction have a large impact on the cloud radiative forcing at the surface, which is dominated by the longwave flux for this case.

  12. be explained by the indirect aerosol cloud effect. The use of a parcel model to determine the cloud droplet number concentration

    E-Print Network [OSTI]

    Reiners, Peter W.

    cloud properties and their effect on the surface radiation budget: selected cases from FIRE ACE. Jbe explained by the indirect aerosol cloud effect. The use of a parcel model to determine the cloud droplet number concentration enables us to separate the effects of the cloud LWP and cloud droplet number

  13. Summary of the cloud chemistry modeling intercomparison: Photochemical box model simulation

    E-Print Network [OSTI]

    Jacobson, Mark

    not coincide with the appearance and disappearance of cloud were quite large. To better quantify the effect troposphere. Because clouds scatter solar radiation, the actinic flux and consequently photo- dissociation understanding of the effect of clouds on tropospheric chemistry, but these models need to be evaluated

  14. Using cloud resolving model simulations of deep convection to inform cloud parameterizations in large-scale models

    SciTech Connect (OSTI)

    Klein, Stephen A.; Pincus, Robert; Xu, Kuan-man

    2003-06-23T23:59:59.000Z

    Cloud parameterizations in large-scale models struggle to address the significant non-linear effects of radiation and precipitation that arise from horizontal inhomogeneity in cloud properties at scales smaller than the grid box size of the large-scale models. Statistical cloud schemes provide an attractive framework to self-consistently predict the horizontal inhomogeneity in radiation and microphysics because the probability distribution function (PDF) of total water contained in the scheme can be used to calculate these non-linear effects. Statistical cloud schemes were originally developed for boundary layer studies so extending them to a global model with many different environments is not straightforward. For example, deep convection creates abundant cloudiness and yet little is known about how deep convection alters the PDF of total water or how to parameterize these impacts. These issues are explored with data from a 29 day simulation by a cloud resolving model (CRM) of the July 1997 ARM Intensive Observing Period at the Southern Great Plains site. The simulation is used to answer two questions: (a) how well can the beta distribution represent the PDFs of total water relative to saturation resolved by the CRM? (b) how can the effects of convection on the PDF be parameterized? In addition to answering these questions, additional sections more fully describe the proposed statistical cloud scheme and the CRM simulation and analysis methods.

  15. Radiation Parameterization for Three-Dimensional Inhomogeneous Cirrus Clouds Applied to ARM Data and Climate Models

    SciTech Connect (OSTI)

    Kuo-Nan Liou

    2003-12-29T23:59:59.000Z

    OAK-B135 (a) We developed a 3D radiative transfer model to simulate the transfer of solar and thermal infrared radiation in inhomogeneous cirrus clouds. The model utilized a diffusion approximation approach (four-term expansion in the intensity) employing Cartesian coordinates. The required single-scattering parameters, including the extinction coefficient, single-scattering albedo, and asymmetry factor, for input to the model, were parameterized in terms of the ice water content and mean effective ice crystal size. The incorporation of gaseous absorption in multiple scattering atmospheres was accomplished by means of the correlated k-distribution approach. In addition, the strong forward diffraction nature in the phase function was accounted for in each predivided spatial grid based on a delta-function adjustment. The radiation parameterization developed herein is applied to potential cloud configurations generated from GCMs to investigate broken clouds and cloud-overlapping effects on the domain-averaged heating rate. Cloud inhomogeneity plays an important role in the determination of flux and heating rate distributions. Clouds with maximum overlap tend to produce less heating than those with random overlap. Broken clouds show more solar heating as well as more IR cooling as compared to a continuous cloud field (Gu and Liou, 2001). (b) We incorporated a contemporary radiation parameterization scheme in the UCLA atmospheric GCM in collaboration with the UCLA GCM group. In conjunction with the cloud/radiation process studies, we developed a physically-based cloud cover formation scheme in association with radiation calculations. The model clouds were first vertically grouped in terms of low, middle, and high types. Maximum overlap was then used for each cloud type, followed by random overlap among the three cloud types. Fu and Liou's 1D radiation code with modification was subsequently employed for pixel-by-pixel radiation calculations in the UCLA GCM. We showed that the simulated cloud cover and OLR fields without special tuning are comparable to those of ISCCP dataset and the results derived from radiation budget experiments. Use of the new radiation and cloud schemes enhances the radiative warming in the middle to upper tropical troposphere and alleviates the cold bias in the UCLA atmospheric GCM. We also illustrated that ice crystal size and cloud inhomogeneous are significant factors affecting the radiation budgets at the top of the atmosphere and the surface (Gu et al. 2003). (c) An innovative approach has been developed to construct a 3D field of inhomogeneous clouds in general and cirrus in particular in terms of liquid/ice water content and particle size on the basis of a unification of satellite and ground-based cloud radar data. Satellite remote sensing employing the current narrow-band spectro-radiometers has limitation and only the vertically integrated cloud parameters (optical depth and mean particle size) can be determined. However, by combining the horizontal cloud mapping inferred from satellites with the vertical structure derived from the profiling Doppler cloud radar, a 3D cloud field can be constructed. This represents a new conceptual approach to 3D remote sensing and imaging and offers a new perspective in observing the cloud structure. We applied this novel technique to AVHRR/NOAA satellite and mm-wave cloud radar data obtained from the ARM achieve and assessed the 3D cirrus cloud field with the ice crystal size distributions independently derived from optical probe measurements aboard the University of North Dakota Citation. The retrieved 3D ice water content and mean effective ice crystal size involving an impressive cirrus cloud occurring on April 18, 1997, are shown to be comparable to those derived from the analysis of collocated and coincident in situ aircraft measurements (Liou et al. 2002). (d) Detection of thin cirrus with optical depths less than 0.5, particularly those occurring i n the tropics remains a fundamental problem in remote sensing. We developed a new detection scheme for the

  16. Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical modeling of drizzle evolution

    E-Print Network [OSTI]

    Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical I, the influence of cloud microphysics and dynamics on the shape of cloud radar Doppler spectra in warm stratiform clouds was discussed. The traditional analysis of radar Doppler moments was extended

  17. COMPUTATIONAL MODELING OF ELECTRON CLOUD FOR MEIC

    SciTech Connect (OSTI)

    S. Ahmed, B. Yunn, J. Dolph, T. Satogata, G.A. Krafft

    2012-07-01T23:59:59.000Z

    This work is the continuation of [4] our earlier studies on electron cloud (EC) simulations for the medium energy electron-ion collider (MEIC) envisioned at Jefferson Lab beyond the 12 GeV upgrade of CEBAF. In this paper, we study the EC saturation density with various MEIC operational parameters. The details of the study shows saturation of line density 1.7 nC/m and tune shift per unit length 4.9 x 10{sup -7} m{sup -1}.

  18. A Global Cloud Resolving Model Goals

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1 Q2you aA DeepAGlobal Cloud

  19. Evaluating the present-day simulation of clouds, precipitation, and radiation in climate models

    E-Print Network [OSTI]

    Robert, Pincus

    , and net cloud radiative effect, projected cloud fraction, and surface precipitation rate) over the globalEvaluating the present-day simulation of clouds, precipitation, and radiation in climate models] This paper describes a set of metrics for evaluating the simulation of clouds, radiation, and precipitation

  20. Cloud and Star Formation in Disk Galaxy Models with Feedback

    E-Print Network [OSTI]

    Rahul Shetty; Eve C. Ostriker

    2008-05-26T23:59:59.000Z

    We include feedback in global hydrodynamic simulations in order to study the star formation properties, and gas structure and dynamics, in models of galactic disks. We extend previous models by implementing feedback in gravitationally bound clouds: momentum is injected at a rate proportional to the star formation rate. This mechanical energy disperses cloud gas back into the surrounding ISM, truncating star formation in a given cloud, and raising the overall level of ambient turbulence. Propagating star formation can however occur as expanding shells collide, enhancing the density and triggering new cloud and star formation. By controlling the momentum injection per massive star and the specific star formation rate in dense gas, we find that the negative effects of high turbulence outweigh the positive ones, and in net feedback reduces the fraction of dense gas and thus the overall star formation rate. The properties of the large clouds that form are not, however, very sensitive to feedback, with cutoff masses of a few million solar masses, similar to observations. We find a relationship between the star formation rate surface density and the gas surface density with a power law index ~2 for our models with the largest dynamic range, consistent with theoretical expectations for our model of disk flaring. We point out that the value of the "Kennicutt-Schmidt" index depends on the thickness of the disk. With our simple feedback prescription (a single combined star formation event per cloud), we find that global spiral patterns are not sustained; less correlated feedback and smaller scale turbulence appear to be necessary for spiral patterns to persist.

  1. Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Avramov, A.; Harringston, J.Y.; Verlinde, J.

    2005-03-18T23:59:59.000Z

    Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic (Curry et al. 2000) and through various feedback mechanisms exert a strong influence on the Arctic climate. Perhaps one of the most intriguing of their features is that they tend to have liquid tops that precipitate ice. Despite the fact that this situation is colloidally unstable, these cloud systems are quite long lived - from a few days to over a couple of weeks. It has been hypothesized that mixed-phase clouds are maintained through a balance between liquid water condensation resulting from the cloud-top radiative cooling and ice removal by precipitation (Pinto 1998; Harrington et al. 1999). In their modeling study Harrington et al. (1999) found that the maintenance of this balance depends strongly on the ambient concentration of ice forming nucleus (IFN). In a follow-up study, Jiang et al. (2002), using only 30% of IFN concentration predicted by Meyers et al. (1992) IFN parameterization were able to obtain results similar to the observations reported by Pinto (1998). The IFN concentration measurements collected during the Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004 over the North Slope of Alaska and the Beaufort Sea (Verlinde et al. 2005), also showed much lower values then those predicted (Prenne, pers. comm.) by currently accepted ice nucleation parameterizations (e.g. Meyers et al. 1992). The goal of this study is to use the extensive IFN data taken during M-PACE to examine what effects low IFN concentrations have on mesoscale cloud structure and coastal dynamics.

  2. Cloud vertical distribution from radiosonde, remote sensing, and model simulations

    E-Print Network [OSTI]

    Li, Zhanqing

    Cloud vertical distribution from radiosonde, remote sensing, and model simulations Jinqiang Zhang's radiation budget and atmospheric adiabatic heating. Yet it is among the most difficult quantities to observe Great Plains and along with ground- based and space-borne remote sensing products, use it to evaluate

  3. Dynamical modeling of the Deep Impact dust ejecta cloud

    E-Print Network [OSTI]

    Tanyu Bonev; Nancy Ageorges; Stefano Bagnulo; Luis Barrera; Hermann B{ö}hnhardt; Olivier Hainaut; Emmanuel Jehin; Hans-Ullrich K{ä}ufl; Florian Kerber; Gaspare LoCurto; Jean Manfroid; Olivier Marco; Eric Pantin; Emanuela Pompei; Ivo Saviane; Fernando Selman; Chris Sterken; Heike Rauer; Gian Paolo Tozzi; Michael Weiler

    2007-03-21T23:59:59.000Z

    The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2, the FOcal Reducer and low dispersion Spectrograph for the VLT of the European Southern Observatory (ESO), to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud.

  4. Cloud-Based Model Calibration Using OpenStudio: Preprint

    SciTech Connect (OSTI)

    Hale, E.; Lisell, L.; Goldwasser, D.; Macumber, D.; Dean, J.; Metzger, I.; Parker, A.; Long, N.; Ball, B.; Schott, M.; Weaver, E.; Brackney, L.

    2014-03-01T23:59:59.000Z

    OpenStudio is a free, open source Software Development Kit (SDK) and application suite for performing building energy modeling and analysis. The OpenStudio Parametric Analysis Tool has been extended to allow cloud-based simulation of multiple OpenStudio models parametrically related to a baseline model. This paper describes the new cloud-based simulation functionality and presents a model cali-bration case study. Calibration is initiated by entering actual monthly utility bill data into the baseline model. Multiple parameters are then varied over multiple iterations to reduce the difference between actual energy consumption and model simulation results, as calculated and visualized by billing period and by fuel type. Simulations are per-formed in parallel using the Amazon Elastic Cloud service. This paper highlights model parameterizations (measures) used for calibration, but the same multi-nodal computing architecture is available for other purposes, for example, recommending combinations of retrofit energy saving measures using the calibrated model as the new baseline.

  5. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    SciTech Connect (OSTI)

    Klein, S A; McCoy, R B; Morrison, H; Ackerman, A; Avramov, A; deBoer, G; Chen, M; Cole, J; DelGenio, A; Golaz, J; Hashino, T; Harrington, J; Hoose, C; Khairoutdinov, M; Larson, V; Liu, X; Luo, Y; McFarquhar, G; Menon, S; Neggers, R; Park, S; Poellot, M; von Salzen, K; Schmidt, J; Sednev, I; Shipway, B; Shupe, M; Spangenberg, D; Sud, Y; Turner, D; Veron, D; Falk, M; Foster, M; Fridlind, A; Walker, G; Wang, Z; Wolf, A; Xie, S; Xu, K; Yang, F; Zhang, G

    2008-02-27T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics indicate that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is some evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics. This case study, which has been well observed from both aircraft and ground-based remote sensors, could be a benchmark for model simulations of mixed-phase clouds.

  6. Modeling clouds observed at SHEBA using a bulk microphysics parameterization implemented into a single-column model

    E-Print Network [OSTI]

    Shupe, Matthew

    cloud fraction, that is, underpredicting the frequency of liquid- or mixed-phase clouds. The mean ice associated with leads, ``clear-sky'' ice crystal precipitation, and persis- tent mixed-phase clouds. BiasesModeling clouds observed at SHEBA using a bulk microphysics parameterization implemented

  7. Spatial motion of the Magellanic Clouds. Tidal models ruled out?

    E-Print Network [OSTI]

    Ruzicka, Adam; Palous, Jan

    2008-01-01T23:59:59.000Z

    Recently, Kallivayalil et al. derived new values of the proper motion for the Large and Small Magellanic Clouds (LMC and SMC, respectively). The spatial velocities of both Clouds are unexpectedly higher than their previous values resulting from agreement between the available theoretical models of the Magellanic System and the observations of neutral hydrogen (HI) associated with the LMC and the SMC. Such proper motion estimates are likely to be at odds with the scenarios for creation of the large-scale structures in the Magellanic System suggested so far. We investigated this hypothesis for the pure tidal models, as they were the first ones devised to explain the evolution of the Magellanic System, and the tidal stripping is intrinsically involved in every model assuming the gravitational interaction. The parameter space for the Milky Way (MW)-LMC-SMC interaction was analyzed by a robust search algorithm (genetic algorithm) combined with a fast restricted N-body model of the interaction. Our method extended ...

  8. Dust properties inside molecular clouds from coreshine modeling and observations

    E-Print Network [OSTI]

    Lefčvre, Charlčne; Juvela, Mika; Paladini, Roberta; Lallement, Rosine; Marshall, D J; Andersen, Morten; Bacmann, Aurore; Mcgee, Peregrine M; Montier, Ludovic; Noriega-Crespo, Alberto; Pelkonen, V -M; Ristorcelli, Isabelle; Steinacker, Jürgen

    2014-01-01T23:59:59.000Z

    Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\\mu$m that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend of surface bright- nesses and intensity ratios of both coreshine and near-infrared observation...

  9. Use of a lidar forward model for global comparisons of cloud fraction

    E-Print Network [OSTI]

    Hogan, Robin

    555 Use of a lidar forward model for global comparisons of cloud fraction between the ICESat lidar in extinction-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%. 1. Introduction Clouds play a major role in the Earth's radiation budget and predictions

  10. Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations

    E-Print Network [OSTI]

    Sun, Dezheng

    ). A small change in these radiative effects of water vapor and clouds can either offset or greatly amplify global warming, we find no significant correlation between the inter-model variations in the cloud albedo feedback during ENSO and the inter-model variations in the cloud albedo feedback during global warming

  11. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    SciTech Connect (OSTI)

    Klein, Stephen A.; McCoy, Renata B.; Morrison, Hugh; Ackerman, Andrew S.; Avramov, Alexander; de Boer, Gijs; Chen, Mingxuan; Cole, Jason N.S.; Del Genio, Anthony D.; Falk, Michael; Foster, Michael J.; Fridlind, Ann; Golaz, Jean-Christophe; Hashino, Tempei; Harrington, Jerry Y.; Hoose, Corinna; Khairoutdinov, Marat F.; Larson, Vincent E.; Liu, Xiaohong; Luo, Yali; McFarquhar, Greg M.; Menon, Surabi; Neggers, Roel A. J.; Park, Sungsu; Poellot, Michael R.; Schmidt, Jerome M.; Sednev, Igor; Shipway, Ben J.; Shupe, Matthew D.; Spangenberg, Douglas A.; Sud, Yogesh C.; Turner, David D.; Veron, Dana E.; von Salzen, Knut; Walker, Gregory K.; Wang, Zhien; Wolf, Audrey B.; Xie, Shaocheng; Xu, Kuan-Man; Yang, Fanglin; Zhang, Gong

    2009-02-02T23:59:59.000Z

    Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed average liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the average mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics suggest that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics.

  12. Modeling aerosol growth by aqueous chemistry in nonprecipitating stratiform cloud

    SciTech Connect (OSTI)

    Ovchinnikov, Mikhail; Easter, Richard C.

    2010-07-29T23:59:59.000Z

    A new microphysics module based on a two-dimensional (2D) joint size distribution function representing both interstitial and cloud particles is developed and applied to studying aerosol processing in non-precipitating stratocumulus clouds. The module is implemented in a three-dimensional dynamical framework of a large-eddy simulation (LES) model and in a trajectory ensemble model (TEM). Both models are used to study the modification of sulfate aerosol by the activation - aqueous chemistry - resuspension cycle in shallow marine stratocumulus clouds. The effect of particle mixing and different size-distribution representations on modeled aerosol processing are studied in a comparison of the LES and TEM simulations with the identical microphysics treatment exposes and a comparison of TEM simulations with a 2D fixed and moving bin microphysics. Particle mixing which is represented in LES and neglected in the TEM leads to the mean relative per particle dry mass change in the TEM simulations being about 30% lower than in analogous subsample of LES domain. Particles in the final LES spectrum are mixed in from different “parcels”, some of which have experienced longer in-cloud residence times than the TEM parcels, all of which originated in the subcloud layer, have. The mean relative per particle dry mass change differs by 14% between TEM simulations with fixed and moving bin microphysics. Finally, the TEM model with the moving bin microphysics is used to evaluate assumptions about liquid water mass partitioning among activated cloud condensation nuclei (CCN) of different dry sizes. These assumptions are used in large-scale models to map the bulk aqueous chemistry sulfate production, which is largely proportional to the liquid water mass, to the changes in aerosol size distribution. It is shown that the commonly used assumptions that the droplet mass is independent of CCN size or that the droplet mass is proportional to the CCN size to the third power do not perform well in the considered case. The explicitly predicted water partitioning indicates that the mean mass of droplets participating in the models aqueous chemistry calculations is proportional to the dry CCN size.

  13. Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model CAM2 Against Satellite Observations

    E-Print Network [OSTI]

    Bretherton, Chris

    Evaluation of Clouds and Their Radiative Effects Simulated by the NCAR Community Atmospheric Model-4738 (Accepted) #12;1 ABSTRACT Cloud climatology and the cloud radiative forcing at the top cloud radiative forcing at the TOA at different latitudes. The differences of cloud vertical structures

  14. Trace-Based Analysis and Prediction of Cloud Computing User Behavior Using the Fractal Modeling Technique

    E-Print Network [OSTI]

    Pedram, Massoud

    Trace-Based Analysis and Prediction of Cloud Computing User Behavior Using the Fractal Modeling and technology. In this paper, we investigate the characteristics of the cloud computing requests received the alpha- stable distribution. Keywords- cloud computing; alpha-stable distribution; fractional order

  15. Ice Formation in Arctic Mixed-Phase Clouds: Insights from a 3-D Cloud-Resolving Model with Size-Resolved Aerosol and Cloud Microphysics

    SciTech Connect (OSTI)

    Fan, Jiwen; Ovtchinnikov, Mikhail; Comstock, Jennifer M.; McFarlane, Sally A.; Khain, Alexander

    2009-02-27T23:59:59.000Z

    The single-layer mixed-phase clouds observed during the Atmospheric Radiation Measurement (ARM) program’s Mixed-Phase Arctic Cloud Experiment (MPACE) are simulated with a 3-dimensional cloud-resolving model the System for Atmospheric Modeling (SAM) coupled with an explicit bin microphysics scheme and a radar-lidar simulator. Two possible ice enhancement mechanisms – activation of droplet evaporation residues by condensation-followed-by-freezing and droplet freezing by contact freezing inside-out, are scrutinized by extensive comparisons with aircraft and radar and lidar measurements. The locations of ice initiation associated with each mechanism and the role of ice nuclei (IN) in the evolution of mixed-phase clouds are mainly addressed. Simulations with either mechanism agree well with the in-situ and remote sensing measurements on ice microphysical properties but liquid water content is slightly underpredicted. These two mechanisms give very similar cloud microphysical, macrophysical, dynamical, and radiative properties, although the ice nucleation properties (rate, frequency and location) are completely different. Ice nucleation from activation of evaporation nuclei is most efficient near cloud top areas concentrated on the edges of updrafts, while ice initiation from the drop freezing process has no significant location preference (occurs anywhere that droplet evaporation is significant). Both enhanced nucleation mechanisms contribute dramatically to ice formation with ice particle concentration of 10-15 times higher relative to the simulation without either of them. The contribution of ice nuclei (IN) recycling from ice particle evaporation to IN and ice particle concentration is found to be very significant in this case. Cloud can be very sensitive to IN initially and form a nonquilibrium transition condition, but become much less sensitive as cloud evolves to a steady mixed-phase condition. The parameterization of Meyers et al. [1992] with the observed MPACE IN concentration is able to predict the observed mixed-phase clouds reasonably well. This validation may facilitate the application of this parameterization in the cloud and climate models to simulate Arctic clouds.

  16. Cloud/Aerosol Parameterizations: Application and Improvement of General Circulation Models

    SciTech Connect (OSTI)

    Penner, Joyce

    2012-06-30T23:59:59.000Z

    One of the biggest uncertainties associated with climate models and climate forcing is the treatment of aerosols and their effects on clouds. The effect of aerosols on clouds can be divided into two components: The first indirect effect is the forcing associated with increases in droplet concentrations; the second indirect effect is the forcing associated with changes in liquid water path, cloud morphology, and cloud lifetime. Both are highly uncertain. This project applied a cloud-resolving model to understand the response of clouds under a variety of conditions to changes in aerosols. These responses are categorized according to the large-scale meteorological conditions that lead to the response. Meteorological conditions were sampled from various fields, which, together with a global aerosol model determination of the change in aerosols from present day to pre-industrial conditions, was used to determine a first order estimate of the response of global cloud fields to changes in aerosols. The response of the clouds in the NCAR CAM3 GCM coupled to our global aerosol model were tested by examining whether the response is similar to that of the cloud resolving model and methods for improving the representation of clouds and cloud/aerosol interactions were examined.

  17. Process-model Simulations of Cloud Albedo Enhancement by Aerosols in the Arctic

    SciTech Connect (OSTI)

    Kravitz, Benjamin S.; Wang, Hailong; Rasch, Philip J.; Morrison, H.; Solomon, Amy

    2014-11-17T23:59:59.000Z

    A cloud-resolving model is used to simulate the effectiveness of Arctic marine cloud brightening via injection of cloud condensation nuclei (CCN). An updated cloud microphysical scheme is employed, with prognostic CCN and cloud particle numbers in both liquid and mixed-phase marine low clouds. Injection of CCN into the marine boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. Because nearly all of the albedo effects are in the liquid phase due to the removal of ice water by snowfall when ice processes are involved, albedo increases are stronger for pure liquid clouds than mixed-phase clouds. Liquid precipitation can be suppressed by CCN injection, whereas ice precipitation (snow) is affected less; thus the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. CCN injection into a clean regime results in a greater albedo increase than injection into a polluted regime, consistent with current knowledge about aerosol-cloud interactions. Unlike previous studies investigating warm clouds, dynamical changes in circulation due to precipitation changes are small.

  18. Use of a Lidar Forward Model for Global Comparisons of Cloud Fraction between the ICESat Lidar and the ECMWF Model

    E-Print Network [OSTI]

    Hogan, Robin

    to underestimate cloud cover in the extra-tropical oceans, the trade wind cumulus, the stratocumulus sheets off-to-backscatter ratio and effective radius affect the forward modeled mean cloud fraction by no more than 10%. 1. Introduction Clouds play a major role in the Earth's radiation bud- get and predictions of future climate

  19. Reexamination of the State of the Art Cloud Modeling Shows Real Improvements

    SciTech Connect (OSTI)

    Muehlbauer, Andreas D.; Grabowski, Wojciech W.; Malinowski, S. P.; Ackerman, Thomas P.; Bryan, George; Lebo, Zachary; Milbrandt, Jason; Morrison, H.; Ovchinnikov, Mikhail; Tessendorf, Sarah; Theriault, Julie M.; Thompson, Gregory

    2013-05-25T23:59:59.000Z

    Following up on an almost thirty year long history of International Cloud Modeling Workshops, that started out with a meeting in Irsee, Germany in 1985, the 8th International Cloud Modeling Workshop was held in July 2012 in Warsaw, Poland. The workshop, hosted by the Institute of Geophysics at the University of Warsaw, was organized by Szymon Malinowski and his local team of students and co-chaired by Wojciech Grabowski (NCAR/MMM) and Andreas Muhlbauer (University of Washington). International Cloud Modeling Workshops have been held traditionally every four years typically during the week before the International Conference on Clouds and Precipitation (ICCP) . Rooted in the World Meteorological Organization’s (WMO) weather modification program, the core objectives of the Cloud Modeling Workshop have been centered at the numerical modeling of clouds, cloud microphysics, and the interactions between cloud microphysics and cloud dynamics. In particular, the goal of the workshop is to provide insight into the pertinent problems of today’s state-of-the-art of cloud modeling and to identify key deficiencies in the microphysical representation of clouds in numerical models and cloud parameterizations. In recent years, the workshop has increasingly shifted the focus toward modeling the interactions between aerosols and clouds and provided case studies to investigate both the effects of aerosols on clouds and precipitation as well as the impact of cloud and precipitation processes on aerosols. This time, about 60 (?) scientists from about 10 (?) different countries participated in the workshop and contributed with discussions, oral and poster presentations to the workshop’s plenary and breakout sessions. Several case leaders contributed to the workshop by setting up five observationally-based case studies covering a wide range of cloud types, namely, marine stratocumulus, mid-latitude squall lines, mid-latitude cirrus clouds, Arctic stratus and winter-time orographic clouds and precipitation. Interested readers are encouraged to visit the workshop website at http://www.atmos.washington.edu/~andreasm/workshop2012/ and browse through the list of case studies. The web page also provides a detailed list of participants and the workshop agenda. Aside from contributed oral and poster presentations during the workshop’s plenary sessions, parallel breakout sessions focused on presentations and discussions of the individual cases. A short summary and science highlights from each of the cases is presented below.

  20. Cloud computing adoption model for governments and large enterprises

    E-Print Network [OSTI]

    Trivedi, Hrishikesh

    2013-01-01T23:59:59.000Z

    Cloud Computing has held organizations across the globe spell bound with its promise. As it moves from being a buzz word and hype into adoption, organizations are faced with question of how to best adopt cloud. Existing ...

  1. The Radiative Properties of Small Clouds: Multi-Scale Observations and Modeling

    SciTech Connect (OSTI)

    Feingold, Graham [NOAA ESRL; McComiskey, Allison [CIRES, University of Colorado

    2013-09-25T23:59:59.000Z

    Warm, liquid clouds and their representation in climate models continue to represent one of the most significant unknowns in climate sensitivity and climate change. Our project combines ARM observations, LES modeling, and satellite imagery to characterize shallow clouds and the role of aerosol in modifying their radiative effects.

  2. A GLOBAL MAGNETIC TOPOLOGY MODEL FOR MAGNETIC CLOUDS. I

    SciTech Connect (OSTI)

    Hidalgo, M. A. [Departamento de Fisica, Universidad de Alcala (Spain); Nieves-Chinchilla, T., E-mail: miguel.hidalgo@uah.es, E-mail: teresa.nieves-chinchil-1@nasa.gov [Institute for Astrophysics and Computational Sciences Catholic University of America, Washington, DC (United States)

    2012-04-01T23:59:59.000Z

    We present an analytical approach to the global magnetic field topology of magnetic clouds (MCs) that considers them like close magnetic structures with torus geometry and with a non-uniform (variable maximum radius) cross section along them. Following our previous approach to the problem of MCs (Hidalgo 2003, 2011), we establish an intrinsic coordinate system for that topology, and then we analytically solve the Maxwell equations in terms of it. The purpose of the present work is to present this model, which will lead us to understand in a more realistic way the physical mechanisms inside MCs. The model has a non-force-free character and also takes into account the time evolution of the cross sections of the MCs in their movement through the interplanetary medium. In this first paper, we obtain the expressions for the components of the magnetic field and the plasma current density imposing a large mean radius of the torus, and imposing a circular cross section with a variable maximum radius. Eventually, we fit the model to data related to four well-known MCs measurements at 1 AU, (three of them with circular cross sections and without expansion, as it is deduced from the experimental data). We compare the results of this toroidal model with those obtained with our previous cylindrical circular cross section model, also with a non-force-free character.

  3. MODELLING RADIATIVELY ACTIVE WATER-ICE CLOUDS: IMPACT ON THE THERMAL STRUCTURE AND WATER CYCLE.

    E-Print Network [OSTI]

    Madeleine, Jean-Baptiste

    MODELLING RADIATIVELY ACTIVE WATER-ICE CLOUDS: IMPACT ON THE THERMAL STRUCTURE AND WATER CYCLE. J. The essential role of water-ice clouds in shaping the thermal structure of the martian atmosphere has been long presumed [1] but neglected in GCMs because of the lack of observations and difficulty to predict

  4. Model-driven Configuration of Cloud Computing Auto-scaling Infrastructure

    E-Print Network [OSTI]

    Schmidt, Douglas C.

    Model-driven Configuration of Cloud Computing Auto-scaling Infrastructure Brian Dougherty1 and Jules White2 and Douglas C. Schmidt1 1 Vanderbilt University briand,schmidt@dre.vanderbilt.edu 2 Virginia Tech julesw@vt.edu Abstract. Cloud computing uses virtualized computational resources to allow

  5. Using Stochastically Generated Subcolumns to Represent Cloud Structure in a Large-Scale Model

    E-Print Network [OSTI]

    Robert, Pincus

    condensate amount and cloud fraction, has about the same effect on radiative fluxes as does the ad hoc tuning for representing cloud structure in instantaneous calculations and long-term integrations. Shortwave radiation accounting for this effect in the operational radiation scheme. Long simulations with the new model

  6. Fresh clouds: A parameterized updraft method for calculating cloud densities in one-dimensional models

    E-Print Network [OSTI]

    Atreya, Sushil

    . Mihalka a a Department of Atmospheric, Oceanic, and Space Science, University of Michigan, Ann Arbor, MI 48109-2143, USA b Astronomy Department, University of California, Berkeley, CA 97420-3411, USA c NASA clouds com- posed of ammonia ice, ammonium hydrosulfide or other com- pounds formed by NH3 and H2S, water

  7. A market-power based model of business groups

    E-Print Network [OSTI]

    Feenstra, Robert C; Huang, D S; Hamilton, G G

    2003-01-01T23:59:59.000Z

    complicated. In our model, business groups not only sellof Indian groups. 3. A Model of Business Groups We willa market-power based model of business groups. This We

  8. Cloud Services Cloud Services

    E-Print Network [OSTI]

    Cloud Services Cloud Services In 2012 UCD IT Services launched an exciting new set of cloud solutions called CloudEdu, which includes cloud servers, cloud storage, cloud hosting and cloud network. The CloudEdu package includes a consultancy service in design, deployment, management and utilisation

  9. Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

    E-Print Network [OSTI]

    Klein, Stephen A.

    2009-01-01T23:59:59.000Z

    cloud has the correct effect on surface fluxes of radiation.radiation is 200 W m –2 in clear-sky STREAMER calculations, the longwave cloud radiative effect

  10. Study of Multi-Scale Cloud Processes Over the Tropical Western Pacific Using Cloud-Resolving Models Constrained by Satellite Data

    SciTech Connect (OSTI)

    Dudhia, Jimy

    2013-03-12T23:59:59.000Z

    Clouds in the tropical western Pacific are an integral part of the large scale environment. An improved understanding of the multi-scale structure of clouds and their interactions with the environment is critical to the ARM (Atmospheric Radiation Measurement) program for developing and evaluating cloud parameterizations, understanding the consequences of model biases, and providing a context for interpreting the observational data collected over the ARM Tropical Western Pacific (TWP) sites. Three-dimensional cloud resolving models (CRMs) are powerful tools for developing and evaluating cloud parameterizations. However, a significant challenge in using CRMs in the TWP is that the region lacks conventional data, so large uncertainty exists in defining the large-scale environment for clouds. This project links several aspects of the ARM program, from measurements to providing improved analyses, and from cloud-resolving modeling to climate-scale modeling and parameterization development, with the overall objective to improve the representations of clouds in climate models and to simulate and quantify resolved cloud effects on the large-scale environment. Our objectives will be achieved through a series of tasks focusing on the use of the Weather Research and Forecasting (WRF) model and ARM data. Our approach includes: -- Perform assimilation of COSMIC GPS radio occultation and other satellites products using the WRF Ensemble Kalman Filter assimilation system to represent the tropical large-scale environment at 36 km grid resolution. This high-resolution analysis can be used by the community to derive forcing products for single-column models or cloud-resolving models. -- Perform cloud-resolving simulations using WRF and its nesting capabilities, driven by the improved regional analysis and evaluate the simulations against ARM datasets such as from TWP-ICE to optimize the microphysics parameters for this region. A cirrus study (Mace and co-authors) already exists for TWP-ICE using satellite and ground-based observations. -- Perform numerical experiments using WRF to investigate how convection over tropical islands in the Maritime Continent interacts with large-scale circulation and affects convection in nearby regions. -- Evaluate and apply WRF as a testbed for GCM cloud parameterizations, utilizing the ability of WRF to run on multiple scales (from cloud resolving to global) to isolate resolution and physics issues from dynamical and model framework issues. Key products will be disseminated to the ARM and larger community through distribution of data archives, including model outputs from the data assimilation products and cloud resolving simulations, and publications.

  11. USING CLOUD CLASSIFICATION TO MODEL SOLAR VARIABILITY Matthew...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The objective is to investigate what characteristics of the performance of a solar power system can be distinguished by the type of cloud or weather pattern, as classified by...

  12. Evaluating Clouds, Aerosols, and their Interactions in Three Global Climate Models using COSP and Satellite Observations

    SciTech Connect (OSTI)

    Ban-Weiss, George; Jin, Ling; Bauer, S.; Bennartz, Ralph; Liu, Xiaohong; Zhang, Kai; Ming, Yi; Guo, Huan; Jiang, Jonathan

    2014-09-23T23:59:59.000Z

    Accurately representing aerosol-cloud interactions in global climate models is challenging. As parameterizations evolve, it is important to evaluate their performance with appropriate use of observations. In this work we compare aerosols, clouds, and their interactions in three climate models (AM3, CAM5, ModelE) to MODIS satellite observations. Modeled cloud properties were diagnosed using the CFMIP Observations Simulator Package (COSP). Cloud droplet number concentrations (N) were derived using the same algorithm for both satellite-simulated model values and observations. We find that aerosol optical depth tau simulated by models is similar to observations. For N, AM3 and CAM5 capture the observed spatial pattern of higher values in near-coast versus remote ocean regions, though modeled values in general are higher than observed. In contrast, ModelE simulates lower N in most near-coast versus remote regions. Aerosol- cloud interactions were computed as the sensitivity of N to tau for marine liquid clouds off the coasts of South Africa and Eastern Asia where aerosol pollution varies in time. AM3 and CAM5 are in most cases more sensitive than observations, while the sensitivity for ModelE is statistically insignificant. This widely used sensitivity could be subject to misinterpretation due to the confounding influence of meteorology on both aerosols and clouds. A simple framework for assessing the N – tau sensitivity at constant meteorology illustrates that observed sensitivity can change from positive to statistically insignificant when including the confounding influence of relative humidity. Satellite simulated values of N were compared to standard model output and found to be higher with a bias of 83 cm-3.

  13. Model analysis of the anthropogenic aerosol effect on clouds over East Asia

    SciTech Connect (OSTI)

    Gao, Yi; Zhang, Meigen; Liu, Xiaohong; Zhao, Chun

    2012-01-16T23:59:59.000Z

    A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (PI) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm{sup -3} over the ocean and East China, 400 cm{sup -3} over Central and Southwest China, and less than 200 cm{sup -3} over North China. The cloud liquid water path (LWP) increased by 40-60 g m{sup -2} over the ocean and Southeast China and 30 g m{sup -2} over Central China; the LWP increased less than 5 g m{sup -2} or decreased by 5 g m{sup -2} over North China. The effective radius (Re) decreased by more than 4 {mu}m over Southwest, Central, and Southeast China and 2 {mu}m over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250-400 cm{sup -3}, the LWP increased by approximately 30-50 g m{sup -2}, and Re decreased by approximately 3 {mu}m over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative forcing strengthened by 30 W m{sup -2} over the ocean and 10 W m{sup -2} over Southeast China, and it weakened slightly by approximately 2-10 W m{sup -2} over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m{sup -2} over Southeast and North China and weakened by 10 W m{sup -2} over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.

  14. A CATALOG OF ULTRA-COMPACT HIGH VELOCITY CLOUDS FROM THE ALFALFA SURVEY: LOCAL GROUP GALAXY CANDIDATES?

    SciTech Connect (OSTI)

    Adams, Elizabeth A. K.; Giovanelli, Riccardo; Haynes, Martha P., E-mail: betsey@astro.cornell.edu, E-mail: riccardo@astro.cornell.edu, E-mail: haynes@astro.cornell.edu [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States)

    2013-05-01T23:59:59.000Z

    We present a catalog of 59 ultra-compact high velocity clouds (UCHVCs) extracted from the 40% complete ALFALFA HI-line survey. The ALFALFA UCHVCs have median flux densities of 1.34 Jy km s{sup -1}, median angular diameters of 10', and median velocity widths of 23 km s{sup -1}. We show that the full UCHVC population cannot easily be associated with known populations of high velocity clouds. Of the 59 clouds presented here, only 11 are also present in the compact cloud catalog extracted from the commensal GALFA-HI survey, demonstrating the utility of this separate dataset and analysis. Based on their sky distribution and observed properties, we infer that the ALFALFA UCHVCs are consistent with the hypothesis that they may be very low mass galaxies within the Local Volume. In that case, most of their baryons would be in the form of gas, and because of their low stellar content, they remain unidentified by extant optical surveys. At distances of {approx}1 Mpc, the UCHVCs have neutral hydrogen (H I) masses of {approx}10{sup 5}-10{sup 6} M{sub Sun }, H I diameters of {approx}2-3 kpc, and indicative dynamical masses within the H I extent of {approx}10{sup 7}-10{sup 8} M{sub Sun }, similar to the Local Group ultra-faint dwarf Leo T. The recent ALFALFA discovery of the star-forming, metal-poor, low mass galaxy Leo P demonstrates that this hypothesis is true in at least one case. In the case of the individual UCHVCs presented here, confirmation of their extragalactic nature will require further work, such as the identification of an optical counterpart to constrain their distance.

  15. Sensitivity of photolysis frequencies and key tropospheric oxidants in a global model to cloud vertical distributions and optical properties

    E-Print Network [OSTI]

    Liu, Hongyu

    in the tropical upper troposphere. We find that the radiative impact of clouds on global photolysis frequencies(O1 D), J(NO2)) due to the radiative effects of clouds in June are about 0.0% (0.4%, 0.9%), 0.8% (1Sensitivity of photolysis frequencies and key tropospheric oxidants in a global model to cloud

  16. Cloud speed impact on solar variability scaling â?? Application to the wavelet variability model

    E-Print Network [OSTI]

    Lave, Matthew; Kleissl, Jan

    2013-01-01T23:59:59.000Z

    Kleissl, J. , 2013. Deriving cloud velocity from an array ofCloud Speed Impact on Solar Variability Scaling -this work, we determine from cloud speeds. Cloud simulator

  17. Modeling Residential Urban Areas from Dense Aerial LiDAR Point Clouds

    E-Print Network [OSTI]

    Shahabi, Cyrus

    Modeling Residential Urban Areas from Dense Aerial LiDAR Point Clouds Qian-Yi Zhou and Ulrich models for residential areas from aerial LiDAR scans. The key differ- ence between downtown area modeling and residential area modeling is that the latter usually contains rich vegetation. Thus, we propose a robust

  18. Ad hoc cloud computing 

    E-Print Network [OSTI]

    McGilvary, Gary Andrew

    2014-11-27T23:59:59.000Z

    Commercial and private cloud providers offer virtualized resources via a set of co-located and dedicated hosts that are exclusively reserved for the purpose of offering a cloud service. While both cloud models appeal to ...

  19. Development and Testing of a Life Cycle Model and a Parameterization of Thin Mid-level Stratiform Clouds

    SciTech Connect (OSTI)

    Krueger, Steven K.

    2008-03-03T23:59:59.000Z

    We used a cloud-resolving model (a detailed computer model of cloud systems) to evaluate and improve the representation of clouds in global atmospheric models used for numerical weather prediction and climate modeling. We also used observations of the atmospheric state, including clouds, made at DOE's Atmospheric Radiation Measurement (ARM) Program's Climate Research Facility located in the Southern Great Plains (Kansas and Oklahoma) during Intensive Observation Periods to evaluate our detailed computer model as well as a single-column version of a global atmospheric model used for numerical weather prediction (the Global Forecast System of the NOAA National Centers for Environmental Prediction). This so-called Single-Column Modeling approach has proved to be a very effective method for testing the representation of clouds in global atmospheric models. The method relies on detailed observations of the atmospheric state, including clouds, in an atmospheric column comparable in size to a grid column used in a global atmospheric model. The required observations are made by a combination of in situ and remote sensing instruments. One of the greatest problems facing mankind at the present is climate change. Part of the problem is our limited ability to predict the regional patterns of climate change. In order to increase this ability, uncertainties in climate models must be reduced. One of the greatest of these uncertainties is the representation of clouds and cloud processes. This project, and ARM taken as a whole, has helped to improve the representation of clouds in global atmospheric models.

  20. Cloud Controlling Factors --Low Clouds BJORN STEVENS,

    E-Print Network [OSTI]

    Stevens, Bjorn

    Cloud Controlling Factors -- Low Clouds BJORN STEVENS, Department of Atmospheric and Oceanic) clouds is reviewed, with an emphasis on factors that may be expected to change in a changing climate of low-cloud control- ling processes are offered: these include renewing our focus on theory, model

  1. Cloud Controlling Factors --Low Clouds BJORN STEVENS,

    E-Print Network [OSTI]

    Stevens, Bjorn

    Cloud Controlling Factors -- Low Clouds BJORN STEVENS, Department of Atmospheric and Oceanic conspire to determine the statistics and cli- matology of layers of shallow (boundary layer) clouds of low-cloud control- ling processes are offered: these include renewing our focus on theory, model

  2. Effects of cloud overlap in photochemical models Yan Feng, Joyce E. Penner, Sanford Sillman, and Xiaohong Liu

    E-Print Network [OSTI]

    Sillman, Sanford

    Effects of cloud overlap in photochemical models Yan Feng, Joyce E. Penner, Sanford Sillman for radiation and cloud microphysics in general circulation models and for photolysis in photochemical transport their effects on averaged photolysis frequencies and OH concentrations in a global photochemical model

  3. Simulation of Aerosol-Cloud Interactions in the WRF Model at the Southern Great Plains Site 

    E-Print Network [OSTI]

    Vogel, Jonathan 1988-

    2012-08-21T23:59:59.000Z

    The aerosol direct and indirect effects were investigated for three specific cases during the March 2000 Cloud IOP at the SGP site by using a modified WRF model. The WRF model was previously altered to include a two-moment bulk microphysical scheme...

  4. Simulation of Aerosol-Cloud Interactions in the WRF Model at the Southern Great Plains Site

    E-Print Network [OSTI]

    Vogel, Jonathan 1988-

    2012-08-21T23:59:59.000Z

    The aerosol direct and indirect effects were investigated for three specific cases during the March 2000 Cloud IOP at the SGP site by using a modified WRF model. The WRF model was previously altered to include a two-moment bulk microphysical scheme...

  5. The martian mesosphere as revealed by CO2 cloud observations and General Circulation Modeling

    E-Print Network [OSTI]

    Spiga, Aymeric

    a rare dataset of mesospheric winds. We compare the mesospheric zonal winds pre- dicted by the model by the model. Ă? 2011 Elsevier Inc. All rights reserved. 1. Introduction While the formation of CO2 clouds observations on board Mars Global Surveyor (Clancy et al., 2004, 2007), and later confirmed by THEMIS-VIS (Mc

  6. GFDL ARM Project Technical Report: Using ARM Observations to Evaluate Cloud and Convection Parameterizations & Cloud-Convection-Radiation Interactions in the GFDL Atmospheric General Circulation Model

    SciTech Connect (OSTI)

    V. Ramaswamy; L. J. Donner; J-C. Golaz; S. A. Klein

    2010-06-17T23:59:59.000Z

    This report briefly summarizes the progress made by ARM postdoctoral fellow, Yanluan Lin, at GFDL during the period from October 2008 to present. Several ARM datasets have been used for GFDL model evaluation, understanding, and improvement. This includes a new ice fall speed parameterization with riming impact and its test in GFDL AM3, evaluation of model cloud and radiation diurnal and seasonal variation using ARM CMBE data, model ice water content evaluation using ARM cirrus data, and coordination of the TWPICE global model intercomparison. The work illustrates the potential and importance of ARM data for GCM evaluation, understanding, and ultimately, improvement of GCM cloud and radiation parameterizations. Future work includes evaluation and improvement of the new dynamicsPDF cloud scheme and aerosol activation in the GFDL model.

  7. Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave radiometer data are systematically compared to models to quantify and

    E-Print Network [OSTI]

    Hogan, Robin

    Cloud fraction, liquid and ice water contents derived from long-term radar, lidar, and microwave a systematic evaluation of clouds in forecast models. Clouds and their associated microphysical processes for end users of weather forecasts, who may be interested not only in cloud cover, but in other variables

  8. Case study of the 9 April 2009 `brown' cloud: Observations and modeling of convective clouds in Saudi Arabia, David J Delene and Jeffrey S Tilley, University of North Dakota, Grand Forks, ND

    E-Print Network [OSTI]

    Delene, David J.

    Case study of the 9 April 2009 `brown' cloud: Observations and modeling of convective clouds indicated a color change in the accumulated ice. Specifically, the ice color changed from white, during concentrations observed (as well as other changes in the convective cloud properties that were documented

  9. Segmentation of building models from dense 3D point-clouds Joachim Bauer

    E-Print Network [OSTI]

    Schindler, Konrad

    , Institute for Computer Graphics and Vision, Graz University of Technology {bauer,karner,klausSegmentation of building models from dense 3D point-clouds Joachim Bauer , Konrad Karner , Konrad Schindler , Andreas Klaus , Christopher Zach VRVis Research Center for Virtual Reality and Visualization

  10. Cloud Formation in the Plumes of Solar Chimney Power Generation Facilities: A Modeling Study

    E-Print Network [OSTI]

    Nenes, Athanasios

    for a proposed solar chimney facility in southwestern Australia. A range of temperatures and updraft velocities technology for converting solar energy into electricity that has shown promise in recent years is the so1 Cloud Formation in the Plumes of Solar Chimney Power Generation Facilities: A Modeling Study

  11. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    SciTech Connect (OSTI)

    Richard A. Ferrare; David D. Turner

    2011-09-01T23:59:59.000Z

    Project goals: (1) Use the routine surface and airborne measurements at the ARM SGP site, and the routine surface measurements at the NSA site, to continue our evaluations of model aerosol simulations; (2) Determine the degree to which the Raman lidar measurements of water vapor and aerosol scattering and extinction can be used to remotely characterize the aerosol humidification factor; (3) Use the high temporal resolution CARL data to examine how aerosol properties vary near clouds; and (4) Use the high temporal resolution CARL and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds.

  12. Group ignition and combustion of a cloud of char particles under transient conditions

    E-Print Network [OSTI]

    Ramalingam, Suresh Chander

    1988-01-01T23:59:59.000Z

    Correction Factor M/Mrpc. 6. 8 Results with CO Oxidation in the Gas Phase. 6. 8. 1 Ignition 6. 8. 2 Effect of Particle Size on Ignition Times 6. 8. 3 Effect of Ambient Temperature on Ignition 6. 8. 4 CO Ignition 6. 8. 5 Combustion with the Thin Flame... has its own euvelope flame (Figure 2. 1a). If another burning drop is brought near the droplet, then a common flame is formed for the two droplets (Figure 2. 1b). Thus the simplest example of group combustion is the combustion of two single drops...

  13. Simulation of polar stratospheric clouds in the specified dynamics version of the whole atmosphere community climate model

    E-Print Network [OSTI]

    Wegner, T.

    We evaluate the simulation of polar stratospheric clouds (PSCs) in the Specified Dynamics version of the Whole Atmosphere Community Climate Model for the Antarctic winter 2005. In this model, PSCs are assumed to form ...

  14. NON-LTE MODEL ATMOSPHERE ANALYSIS OF THE LARGE MAGELLANIC CLOUD SUPERSOFT X-RAY SOURCE CAL 83

    E-Print Network [OSTI]

    Audard, Marc

    NON-LTE MODEL ATMOSPHERE ANALYSIS OF THE LARGE MAGELLANIC CLOUD SUPERSOFT X-RAY SOURCE CAL 83 Magellanic Cloud. Taken with a 16 month in- terval, the Chandra and XMM-Newton spectra are very similar. They reveal a very rich absorption-line spectrum from the hot white dwarf photosphere but no spectral

  15. Global Simulations of Ice nucleation and Ice Supersaturation with an Improved Cloud Scheme in the Community Atmosphere Model

    SciTech Connect (OSTI)

    Gettelman, A.; Liu, Xiaohong; Ghan, Steven J.; Morrison, H.; Park, Sungsu; Conley, Andrew; Klein, Stephen A.; Boyle, James; Mitchell, David; Li, J-L F.

    2010-09-28T23:59:59.000Z

    A process-based treatment of ice supersaturation and ice-nucleation is implemented in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). The new scheme is designed to allow (1) supersaturation with respect to ice, (2) ice nucleation by aerosol particles and (3) ice cloud cover consistent with ice microphysics. The scheme is implemented with a 4-class 2 moment microphysics code and is used to evaluate ice cloud nucleation mechanisms and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloud occurrence better than previous versions of the model. Simulations indicate heterogeneous freezing and contact nucleation on dust are both potentially important over remote areas of the Arctic. Cloud forcing and hence climate is sensitive to different formulations of the ice microphysics. Arctic radiative fluxes are sensitive to the parameterization of ice clouds. These results indicate that ice clouds are potentially an important part of understanding cloud forcing and potential cloud feedbacks, particularly in the Arctic.

  16. Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model

    SciTech Connect (OSTI)

    Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

    2013-08-16T23:59:59.000Z

    Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

  17. Profiling clouds' inner life | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    life Released: May 29, 2014 Subgrid modeling pinpoints cloud transformation to uncover true reflective power An accurate understanding of clouds over the ocean is important for...

  18. Evaluation of Mixed-Phase Cloud Microphysics Parameterizations with the NCAR Single Column Climate Model (SCAM) and ARM Observations

    SciTech Connect (OSTI)

    Liu, X; Ghan, SJ; Xie, S

    2007-04-01T23:59:59.000Z

    Mixed-phase stratus clouds are ubiquitous in the Arctic and play an important role in climate in this region. However, climate models have generally proven unsuccessful at simulating the partitioning of condensed water into liquid droplets and ice crystals in these Arctic clouds, which affect modeled cloud phase, cloud lifetime and radiative properties. An ice nucleation parameterization and a vapor deposition scheme were developed that together provide a physically-consistent treatment of mixed-phase clouds in global climate models. These schemes have been implemented in the National Center for Atmospheric Research (NCAR) Community Atmospheric Model Version 3 (CAM3). This report documents the performance of these schemes against ARM Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the CAM single column model version (SCAM). SCAM with our new schemes has a more realistic simulation of the cloud phase structure and the partitioning of condensed water into liquid droplets against observations during the M-PACE than the standard CAM simulations.

  19. MODELING THE ATOMIC-TO-MOLECULAR TRANSITION AND CHEMICAL DISTRIBUTIONS OF TURBULENT STAR-FORMING CLOUDS

    SciTech Connect (OSTI)

    Offner, Stella S. R. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Bisbas, Thomas G.; Viti, Serena [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6B (United Kingdom); Bell, Tom A., E-mail: stella.offner@yale.edu [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, E-28850 Madrid (Spain)

    2013-06-10T23:59:59.000Z

    We use 3D-PDR, a three-dimensional astrochemistry code for modeling photodissociation regions (PDRs), to post-process hydrodynamic simulations of turbulent, star-forming clouds. We focus on the transition from atomic to molecular gas, with specific attention to the formation and distribution of H, C{sup +}, C, H{sub 2}, and CO. First, we demonstrate that the details of the cloud chemistry and our conclusions are insensitive to the simulation spatial resolution, to the resolution at the cloud edge, and to the ray angular resolution. We then investigate the effect of geometry and simulation parameters on chemical abundances and find weak dependence on cloud morphology as dictated by gravity and turbulent Mach number. For a uniform external radiation field, we find similar distributions to those derived using a one-dimensional PDR code. However, we demonstrate that a three-dimensional treatment is necessary for a spatially varying external field, and we caution against using one-dimensional treatments for non-symmetric problems. We compare our results with the work of Glover et al., who self-consistently followed the time evolution of molecule formation in hydrodynamic simulations using a reduced chemical network. In general, we find good agreement with this in situ approach for C and CO abundances. However, the temperature and H{sub 2} abundances are discrepant in the boundary regions (A{sub v} {<=} 5), which is due to the different number of rays used by the two approaches.

  20. SURFACE CLOUD RADIATIVE FORCING, CLOUD FRACTION AND CLOUD ALBEDO: THEIR RELATIONSHIP AND MULTISCALE VARIATION

    E-Print Network [OSTI]

    that have been used to quantify the effect of clouds on radiation budget in both modeling and observationalSURFACE CLOUD RADIATIVE FORCING, CLOUD FRACTION AND CLOUD ALBEDO: THEIR RELATIONSHIP AND MULTISCALE/Atmospheric Sciences Division Brookhaven National Laboratory P.O. Box, Upton, NY www.bnl.gov ABSTRACT Cloud-radiation

  1. Modeling Bright Gamma-ray and Radio Emission at Fast Cloud Shocks

    E-Print Network [OSTI]

    Lee, Shiu-Hang; Raymond, John C; Nagataki, Shigehiro; Slane, Patrick O; Ellison, Donald C

    2015-01-01T23:59:59.000Z

    Recent observations by the Large Area Telescope (LAT) onboard the Fermi satellite have revealed bright gamma-ray emission from middle-aged supernova remnants (SNRs) inside our Galaxy. These remnants, which also possess bright non-thermal radio shells, are often found to be interacting directly with surrounding gas clouds. We explore the non-thermal emission mechanism at these dynamically evolved SNRs by constructing a hydrodynamical model. Two scenarios of particle acceleration, either a re-acceleration of Galactic cosmic rays (CRs) or an efficient nonlinear diffusive shock acceleration (NLDSA) of particles injected from downstream, are considered. Using parameters inferred from observations, our models are contrasted with the observed spectra of SNR W44. For the re-acceleration case, we predict a significant enhancement of radio and GeV emission as the SNR undergoes a transition into the radiative phase. If sufficiently strong magnetic turbulence is present in the molecular cloud, the re-acceleration scenari...

  2. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    SciTech Connect (OSTI)

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    2012-10-25T23:59:59.000Z

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  3. ARM - Midlatitude Continental Convective Clouds - Single Column Model Forcing (xie-scm_forcing)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Xie, Shaocheng; McCoy, Renata; Zhang, Yunyan

    The constrained variational objective analysis approach described in Zhang and Lin [1997] and Zhang et al. [2001]was used to derive the large-scale single-column/cloud resolving model forcing and evaluation data set from the observational data collected during Midlatitude Continental Convective Clouds Experiment (MC3E), which was conducted during April to June 2011 near the ARM Southern Great Plains (SGP) site. The analysis data cover the period from 00Z 22 April - 21Z 6 June 2011. The forcing data represent an average over the 3 different analysis domains centered at central facility with a diameter of 300 km (standard SGP forcing domain size), 150 km and 75 km, as shown in Figure 1. This is to support modeling studies on various-scale convective systems.

  4. Observed Characteristics of Clouds and Precipitating Systems Associated with the Tropical Circulation in Global Models and Reanalyses

    E-Print Network [OSTI]

    Stachnik, Justin Paul

    2013-03-25T23:59:59.000Z

    This dissertation presents a series of work related to the representation of the Hadley circulation (HC) in atmospheric reanalyses and general circulation models (GCMs), with connections to the underlying tropical and subtropical cloud systems...

  5. Cloud speed impact on solar variability scaling â?? Application to the wavelet variability model

    E-Print Network [OSTI]

    Lave, Matthew; Kleissl, Jan

    2013-01-01T23:59:59.000Z

    cloud field. White represents clouds and black representand (b) 25 m s -1 cloud speed. The white x’s mark locationscloud size had errors larger than the 15% threshold, resulting in the white

  6. Evaluation of a New Mixed-Phase Cloud Microphysics Parameterization with CAM3 Single-Column Model and M-PACE Observations

    SciTech Connect (OSTI)

    Liu, Xiaohong; Xie, Shaocheng; Ghan, Steven J.

    2007-12-14T23:59:59.000Z

    Most global climate models generally prescribe the partitioning of condensed water into liquid droplets and ice crystals in mixed-phase clouds according to a temperature-dependent function, which affects modeled cloud phase, cloud lifetime and radiative properties. This study evaluates a new mixed-phase cloud microphysics parameterization (for ice nucleation and water vapor deposition) against the Atmospheric Radiation Measurement (ARM) Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the NCAR Community Atmospheric Model Version 3 (CAM3) single column model (SCAM). It is shown that SCAM with the new scheme produces a more realistic simulation of the cloud phase structure and the partitioning of condensed waterinto liquid droplets against observations during the M-PACE than the standard CAM. Sensitivity test indicates that ice number concentration could play an important role in the simulated mixed-phase cloud microphysics, and thereby needs to be realistically represented in global climate models.

  7. Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report

    SciTech Connect (OSTI)

    Huang, Hsin-Yuan; Hall, Alex

    2013-07-24T23:59:59.000Z

    Stratocumulus and shallow cumulus clouds in subtropical oceanic regions (e.g., Southeast Pacific) cover thousands of square kilometers and play a key role in regulating global climate (e.g., Klein and Hartmann, 1993). Numerical modeling is an essential tool to study these clouds in regional and global systems, but the current generation of climate and weather models has difficulties in representing them in a realistic way (e.g., Siebesma et al., 2004; Stevens et al., 2007; Teixeira et al., 2011). While numerical models resolve the large-scale flow, subgrid-scale parameterizations are needed to estimate small-scale properties (e.g. boundary layer turbulence and convection, clouds, radiation), which have significant influence on the resolved scale due to the complex nonlinear nature of the atmosphere. To represent the contribution of these fine-scale processes to the resolved scale, climate models use various parameterizations, which are the main pieces in the model that contribute to the low clouds dynamics and therefore are the major sources of errors or approximations in their representation. In this project, we aim to 1) improve our understanding of the physical processes in thermal circulation and cloud formation, 2) examine the performance and sensitivity of various parameterizations in the regional weather model (Weather Research and Forecasting model; WRF), and 3) develop, implement, and evaluate the advanced boundary layer parameterization in the regional model to better represent stratocumulus, shallow cumulus, and their transition. Thus, this project includes three major corresponding studies. We find that the mean diurnal cycle is sensitive to model domain in ways that reveal the existence of different contributions originating from the Southeast Pacific land-masses. The experiments suggest that diurnal variations in circulations and thermal structures over this region are influenced by convection over the Peruvian sector of the Andes cordillera, while the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain. According to our experiments, the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer scheme and the WSM6 microphysics scheme is the combination of schemes that performs best. For that combination, mean cloud cover, liquid water path, and cloud depth are fairly wellsimulated, while mean cloud top height remains too low in comparison to observations. Both microphysics and boundary layer schemes contribute to the spread in liquid water path and cloud depth, although the microphysics contribution is slightly more prominent. Boundary layer schemes are the primary contributors to cloud top height, degree of adiabaticity, and cloud cover. Cloud top height is closely related to surface fluxes and boundary layer structure. Thus, our study infers that an appropriate tuning of cloud top height would likely improve the low-cloud representation in the model. Finally, we show that entrainment governs the degree of adiabaticity, while boundary layer decoupling is a control on cloud cover. In the intercomparison study using WRF single-column model experiments, most parameterizations show a poor agreement of the vertical boundary layer structure when compared with large-eddy simulation models. We also implement a new Total-Energy/Mass- Flux boundary layer scheme into the WRF model and evaluate its ability to simulate both stratocumulus and shallow cumulus clouds. Result comparisons against large-eddy simulation show that this advanced parameterization based on the new Eddy-Diffusivity/Mass-Flux approach provides a better performance than other boundary layer parameterizations.

  8. Evaluation of Cloud Type Occurrences and Radiative Forcings Simulated by a Cloud Resolving Model Using Observations from Sa...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1, 13Evacuation EmergencyCloudSat, ARM,Cloud Type

  9. Global Climate Modeling of the Martian water cycle with improved microphysics and radiatively active water ice clouds

    E-Print Network [OSTI]

    Navarro, Thomas; Forget, François; Spiga, Aymeric; Millour, Ehouarn; Montmessin, Franck

    2013-01-01T23:59:59.000Z

    Radiative effects of water ice clouds have noteworthy consequences on the Martian atmosphere, its thermal structure and circulation. Accordingly, the inclusion of such effects in the LMD Mars Global Climate Model (GCM) greatly modifies the simulated Martian water cycle. The intent of this paper is to address the impact of radiatively active clouds on atmospheric water vapor and ice in the GCM and improve its representation. We propose a new enhanced modeling of the water cycle, consisting of detailed cloud microphysics with dynamic condensation nuclei and a better implementation of perennial surface water ice. This physical modeling is based on tunable parameters. This new version of the GCM is compared to the Thermal Emission Spectrometer observations of the water cycle. Satisfying results are reached for both vapor and cloud opacities. However, simulations yield a lack of water vapor in the tropics after Ls=180{\\deg} which is persistent in simulations compared to observations, as a consequence of aphelion c...

  10. Aerosol, Cloud, and Climate: From Observation to Model

    ScienceCinema (OSTI)

    Jian Wang

    2010-09-01T23:59:59.000Z

    Scientists have long been investigating this phenomenon of "global warming," which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions.

  11. Aerosol, Cloud, and Climate: From Observation to Model

    SciTech Connect (OSTI)

    Jian Wang

    2010-05-12T23:59:59.000Z

    Scientists have long been investigating this phenomenon of "global warming," which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions.

  12. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    SciTech Connect (OSTI)

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06T23:59:59.000Z

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  13. The Microwave Thermal Emission from the Zodiacal Dust Cloud Predicted with Contemporary Meteoroid Models

    E-Print Network [OSTI]

    Dikarev, Valery V

    2015-01-01T23:59:59.000Z

    Predictions of the microwave thermal emission from the interplanetary dust cloud are made using several contemporary meteoroid models to construct the distributions of cross-section area of dust in space, and applying the Mie light-scattering theory to estimate the temperatures and emissivities of dust particles in broad size and heliocentric distance ranges. In particular, the model of the interplanetary dust cloud by Kelsall et al. (1998, ApJ 508: 44-73), the five populations of interplanetary meteoroids of Divine (1993, JGR 98(E9): 17,029-17,048) and the Interplanetary Meteoroid Engineering Model (IMEM) by Dikarev et al. (2004, EMP 95: 109-122) are used in combination with the optical properties of olivine, carbonaceous and iron spherical particles. The Kelsall model has been widely accepted by the Cosmic Microwave Background (CMB) community. We show, however, that it predicts the microwave emission from interplanetary dust remarkably different from the results of application of the meteoroid engineering m...

  14. Cloud Business Models and Sustainability: Impacts for businesses and e-Research Accepted by "Software Sustainability" Workshops

    E-Print Network [OSTI]

    by Mathematica. This leads to development of Cloud Sustainability Framework (CSF), which measures cloud business

  15. Evaluation of A New Mixed-Phase Cloud Microphysics Parameterization with the NCAR Climate Atmospheric Model (CAM3) and ARM Observations Fourth Quarter 2007 ARM Metric Report

    SciTech Connect (OSTI)

    X Liu; SJ Ghan; S Xie; J Boyle; SA Klein

    2007-09-30T23:59:59.000Z

    Mixed-phase clouds are composed of a mixture of cloud droplets and ice crystals. The cloud microphysics in mixed-phase clouds can significantly impact cloud optical depth, cloud radiative forcing, and cloud coverage. However, the treatment of mixed-phase clouds in most current climate models is crude and the partitioning of condensed water into liquid droplets and ice crystals is prescribed as temperature dependent functions. In our previous 2007 ARM metric reports a new mixed-phase cloud microphysics parameterization (for ice nucleation and water vapor deposition) was documented and implemented in the NCAR Community Atmospheric Model Version 3 (CAM3). The new scheme was tested against the Atmospheric Radiation Measurement (ARM) Mixed-phase Arctic Cloud Experiment (M-PACE) observations using the single column modeling and short-range weather forecast approaches. In this report this new parameterization is further tested with CAM3 in its climate simulations. It is shown that the predicted ice water content from CAM3 with the new parameterization is in better agreement with the ARM measurements at the Southern Great Plain (SGP) site for the mixed-phase clouds.

  16. Final Report on the Development of an Improved Cloud Microphysical Product for Model and Remote Sensing Evaluation using RACORO Observations

    SciTech Connect (OSTI)

    McFarquhar, Greg

    2012-09-19T23:59:59.000Z

    We proposed to analyze data collected during the Routine Aerial Facilities (AAF) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) in order to develop an integrated product of cloud microphysical properties (number concentration of drops in different size bins, total liquid drop concentration integrated over all bin sizes, liquid water content LWC, extinction of liquid clouds bw, effective radius of water drops re, and radar reflectivity factor) that could be used to evaluate large-eddy simulations (LES), general circulation models (GCMs) and ground-based remote sensing retrievals, and to develop cloud parameterizations with the end goal of improving the modeling of cloud processes and properties and their impact on atmospheric radiation. We have completed the development of this microphysical database and have submitted it to ARM for consideration of its inclusion on the ARM database as a PI product. This report describes the development of this database, and also describes research that has been conducted on cloud-aerosol interactions using the data obtained during RACORO. A list of conference proceedings and publications is also included.

  17. A Model of Absolute Autonomy and Power: Toward Group Effects

    E-Print Network [OSTI]

    Hexmoor, Henry

    575 2420 fax:479 575 5339 Abstract. We present a model of absolute autonomy and power in agent systems present a model that approximates absolute autonomy and power in agent systems. This absolute sense1 A Model of Absolute Autonomy and Power: Toward Group Effects HENRY HEXMOOR Computer Science

  18. Attribution Analysis of Cloud Feedback

    E-Print Network [OSTI]

    Zhou, Chen

    2014-07-15T23:59:59.000Z

    -term global warming. If the EIS-low cloud fraction relationship holds under global warming, it is likely that the tropical low cloud fraction change is non-negative. Climate models without significant negative low cloud fraction change suggest that the cloud...

  19. Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical transport model

    E-Print Network [OSTI]

    Liu, Hongyu

    Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical. (2006), Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical frequencies are calculated using the Fast-J radiative transfer algorithm. The GEOS-3 global cloud optical

  20. Satellite-based remote sensing of cirrus clouds: hyperspectral radiative transfer modeling, analysis of uncertainties in in-situ cloud extinction measurements and intercomparison of cirrus retrievals from a-train instruments 

    E-Print Network [OSTI]

    Zhang, Zhibo

    2009-05-15T23:59:59.000Z

    This dissertation consists of three parts, each devoted to a particular issue of significant importance for satellite-based remote sensing of cirrus clouds. In the first part, we develop and present a fast infrared radiative transfer model...

  1. Attribution Analysis of Cloud Feedback 

    E-Print Network [OSTI]

    Zhou, Chen

    2014-07-15T23:59:59.000Z

    Uncertainty on cloud feedback is the primary contributor to the large spread of equilibrium climate sensitivity (ECS) in climate models. In this study, we compare the short-term cloud feedback in climate models with observations, and evaluate...

  2. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01T23:59:59.000Z

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  3. Aerosol, Cloud, and Climate: From Observation to Model (457th Brookhaven Lecture)

    SciTech Connect (OSTI)

    Wang, Jian (Ph.D., Environmental Sciences Department) [Ph.D., Environmental Sciences Department

    2010-05-12T23:59:59.000Z

    In the last 100 years, the Earth has warmed by about 1şF, glaciers and sea ice have been melting more quickly than previously, especially during the past decade, and the level of the sea has risen about 6-8 inches worldwide. Scientists have long been investigating this phenomenon of “global warming,” which is believed to be at least partly due to the increased carbon dioxide (CO2) concentration in the air from burning fossil fuels. Funded by DOE, teams of researchers from BNL and other national labs have been gathering data in the U.S. and internationally to build computer models of climate and weather to help in understanding general patterns, causes, and perhaps, solutions. Among many findings, researchers observed that atmospheric aerosols, minute particles in the atmosphere, can significantly affect global energy balance and climate. Directly, aerosols scatter and absorb sunlight. Indirectly, increased aerosol concentration can lead to smaller cloud droplets, changing clouds in ways that tend to cool global climate and potentially mask overall warming from man-made CO2.

  4. Mesoscale model cloud scheme assessment using satellite observations Jean-Pierre Chaboureau, Jean-Pierre Cammas, Patrick J. Mascart, and Jean-Pierre Pinty

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    Mesoscale model cloud scheme assessment using satellite observations Jean-Pierre Chaboureau, Jean of the mesoscale nonhydrostatic (Meso-NH) model has been conducted by comparing synthetic METEOSAT brightness combines the output from a bulk explicit cloud scheme routinely used in mesoscale simulations

  5. Validation of the Poisson Stochastic Radiative Transfer Model Against Cloud Cascade Models

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps toValidatingCloudPoisson Stochastic Radiative

  6. Tropical and subtropical cloud transitions in weather and climate prediction models: the GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI)

    SciTech Connect (OSTI)

    Teixeira, J.; Cardoso, S.; Bonazzola, M.; Cole, Jason N.; DelGenio, Anthony D.; DeMott, C.; Franklin, A.; Hannay, Cecile; Jakob, Christian; Jiao, Y.; Karlsson, J.; Kitagawa, H.; Koehler, M.; Kuwano-Yoshida, A.; LeDrian, C.; Lock, Adrian; Miller, M.; Marquet, P.; Martins, J.; Mechoso, C. R.; Meijgaard, E. V.; Meinke, I.; Miranda, P.; Mironov, D.; Neggers, Roel; Pan, H. L.; Randall, David A.; Rasch, Philip J.; Rockel, B.; Rossow, William B.; Ritter, B.; Siebesma, A. P.; Soares, P.; Turk, F. J.; Vaillancourt, P.; Von Engeln, A.; Zhao, M.

    2011-11-01T23:59:59.000Z

    A model evaluation approach is proposed where weather and climate prediction models are analyzed along a Pacific Ocean cross-section, from the stratocumulus regions off the coast of California, across the shallow convection dominated trade-winds, to the deep convection regions of the ITCZ: the GCSS/WGNE Pacific Cross-section Intercomparison (GPCI). The main goal of GPCI is to evaluate, and help understand and improve the representation of tropical and sub-tropical cloud processes in weather and climate prediction models. In this paper, a detailed analysis of cloud regime transitions along the cross-section from the sub-tropics to the tropics for the season JJA of 1998 is presented. This GPCI study confirms many of the typical weather and climate prediction model problems in the representation of clouds: underestimation of clouds in the stratocumulus regime by most models with the corresponding consequences in terms of shortwave radiation biases; overestimation of clouds by the ECMWF Re-Analysis (ERA40) in the deep tropics (in particular) with the corresponding impact in the outgoing longwave radiation; large spread between the different models in terms of cloud cover, liquid water path and shortwave radiation; significant differences between the models in terms of vertical crosssections of cloud properties (in particular), vertical velocity and relative humidity. An alternative analysis of cloud cover mean statistics is proposed where sharp gradients in cloud cover along the GPCI transect are taken into account. This analysis shows that the negative cloud bias of some models and ERA40 in the stratocumulus regions (as compared to ISCCP) is associated not only with lower values of cloud cover in these regimes, but also with a stratocumulus-to-cumulus transition that occurs too early along the trade-wind Lagrangian trajectory. Histograms of cloud cover along the cross-section differ significantly between models. Some models exhibit a quasi-bimodal structure with cloud cover being either very large (close to 100%) or very small, while other models show a more continuous transition. The ISCCP observations suggest that reality is in-between these two extreme examples. These different patterns reflect the diverse nature of the cloud, boundary layer, and convection parameterizations in the participating weather and climate prediction models.

  7. A Survey on Cloud Provider Security

    E-Print Network [OSTI]

    A Survey on Cloud Provider Security Measures Alex Pucher, Stratos Dimopoulos Abstract Cloud take advantage of this model already, but security and privacy concerns limit the further adoption agencies and start offering security certifications and separate tightly controlled "government" cloud

  8. Statistical representation of clouds in a regional model and the impact on the diurnal cycle of convection during Tropical

    E-Print Network [OSTI]

    Chaboureau, Jean-Pierre

    water static energy. Application of the parameterization in a regional model during a 30-day period of the Tropical Convection, Cirrus and Nitrogen Oxides (TROCCINOX) experiment over southern Brazil demonstrates of cloud mass at tropospheric inversions (e.g., trade wind inversion, melting level, tropo- pause

  9. Development and testing of parameterizations for continental and tropical ice cloud microphysical and radiative properties in GCM and mesoscale models. Final report

    SciTech Connect (OSTI)

    Heymsfield, A.

    1997-09-01T23:59:59.000Z

    The overall purpose of this research was to exploit measurements in clouds sampled during several field programs, especially from experiments in tropical regions, in a four-component study to develop and validate cloud parameterizations for general circulation models, emphasizing ice clouds. The components were: (1) parameterization of basic properties of mid- and upper-tropospheric clouds, such as condensed water content, primarily with respect to cirrus from tropical areas; (2) the second component was to develop parameterizations which express cloud radiative properties in terms of basic cloud microphysical properties, dealing primarily with tropical oceanic cirrus clouds and continental thunderstorm anvils, but also including altocumulus clouds; (3) the third component was to validate the parameterizations through use of ground-based measurements calibrated using existing and planned in-situ measurements of cloud microphysical properties and bulk radiative properties, as well as time-resolved data collected over extended periods of time; (4) the fourth component was to implement the parameterizations in the National Center for Atmospheric Research (NCAR) community climate model (CCM) II or in the NOAA-GFDL model (by L. Donner GFDL) and to perform sensitivity studies.

  10. Improvements in Representations of Cloud Microphysics for BBHRP and Models using Data Collected during M-PACE and TWP-ICE

    SciTech Connect (OSTI)

    Greg M. McFarquhar

    2010-02-22T23:59:59.000Z

    In our research we proposed to use data collected during the 2004 Mixed-Phase Arctic Cloud Experiment (MPACE) and the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE) to improve retrievals of ice and mixed-phase clouds, to improve our understanding of how cloud and radiative processes affect cloud life cycles, and to develop and test methods for using ARM data more effectively in model. In particular, we proposed to: 1) use MPACE in-situ data to determine how liquid water fraction and cloud ice and liquid effective radius (r{sub ei} and r{sub ew}) vary with temperature, normalized cloud altitude and other variables for Arctic mixed-phase clouds, and to use these data to evaluate the performance of model parameterization schemes and remote sensing retrieval algorithms; 2) calculate rei and size/shape distributions using TWP-ICE in-situ data, investigate their dependence on cirrus type (oceanic or continental anvils or cirrus not directly traced to convection), and develop and test representations for MICROBASE; 3) conduct fundamental research enhancing our understanding of cloud/radiative interactions, concentrating on effects of small crystals and particle shapes and sizes on radiation; and 4) improve representations of microphysical processes for models (fall-out, effective density, mean scattering properties, rei and rew) and provide them to ARM PIs. In the course of our research, we made substantial progress on all four goals.

  11. Atomistic simulations of amorphous polymers in the cloud with PolymerModeler

    E-Print Network [OSTI]

    Haley, Benjamin P; Wilson, Nathaniel; Jaramillo, Eugenio; Strachan, Alejandro

    2015-01-01T23:59:59.000Z

    Molecular dynamics (MD) simulations enable the description of ma- terial properties and processes with atomistic detail by numerically solv- ing the time evolution of every atom in the system. We introduce Poly- merModeler, a general-purpose, online simulation tool to build atomistic structures of amorphous polymers and perform MD simulations on the re- sulting configurations to predict their thermo-mechanical properties. Poly- merModeler is available, free of charge, at nanoHUB.org via an interactive web interface, and the actual simulations are performed in the cloud us- ing nanoHUB.org resources. Starting from the specification of one or more monomers PolymerModeler builds the polymer chains into a simulation cell with periodic boundary conditions at the desired density. Monomers are added sequentially using the continuous configuration bias direct Monte Carlo method, and copolymers can be created describing the desired se- quence of monomers. PolymerModeler also enables users to perform MD simulations on ...

  12. Correcting transport errors during advection of aerosol and cloud moment sequences in eulerian models

    SciTech Connect (OSTI)

    McGraw R.

    2012-03-01T23:59:59.000Z

    Moment methods are finding increasing usage for simulations of particle population balance in box models and in more complex flows including two-phase flows. These highly efficient methods have nevertheless had little impact to date for multi-moment representation of aerosols and clouds in atmospheric models. There are evidently two reasons for this: First, atmospheric models, especially if the goal is to simulate climate, tend to be extremely complex and take many man-years to develop. Thus there is considerable inertia to the implementation of novel approaches. Second, and more fundamental, the nonlinear transport algorithms designed to reduce numerical diffusion during advection of various species (tracers) from cell to cell, in the typically coarse grid arrays of these models, can and occasionally do fail to preserve correlations between the moments. Other correlated tracers such as isotopic abundances, composition of aerosol mixtures, hydrometeor phase, etc., are subject to this same fate. In the case of moments, this loss of correlation can and occasionally does give rise to unphysical moment sets. When this happens the simulation can come to a halt. Following a brief description and review of moment methods, the goal of this paper is to present two new approaches that both test moment sequences for validity and correct them when they fail. The new approaches work on individual grid cells without requiring stored information from previous time-steps or neighboring cells.

  13. Using simulation to model and understand group learning Maartje Spoelstra

    E-Print Network [OSTI]

    Sklar, Elizabeth

    Using simulation to model and understand group learning Maartje Spoelstra Dept of Computer Science for agents acting in a simulated learning environment. Varying parameter values can change the learning in a simulation that we can use to gain insights into the design of effective learning environments. Here, we

  14. Investigation of a cloud-cover modification to SPCTRAL2, SERI's simple model for cloudless-sky, spectral solar irradiance

    SciTech Connect (OSTI)

    Bird, R.E.; Riordan, C.J.; Myers, D.R.

    1987-06-01T23:59:59.000Z

    This report summarizes the investigation of a cloud-cover modification to SPCTRAL2, SERI's simple model for cloudless-sky, spectral solar irradiance. Our approach was to develop a modifier that relies on commonly acquired meteorological and broadband-irradiance data rather than detailed cloud properties that are generally not available. The method was to normalize modeled, cloudless-sky spectral irradiance to a measured broadband-irradiance value under cloudy skies, and then to compare the normalized, modeled data with measured spectral-irradiance data to empirically derive spectral modifiers that improve the agreement between modeled and measured data. Results indicate the possible form of the spectral corrections; however, we must analyze additional data to develop a spectral transmission function for cloudy-sky conditions.

  15. ICSE Workshop on Green and Sustainable Software Engineering, Zurich, Switzerland, 3rd June 2012 An Energy Consumption Model and Analysis Tool for Cloud Computing

    E-Print Network [OSTI]

    Schneider, Jean-Guy

    system-level optimisation. Keywords-green computing; Cloud computing; energy consumption; performanceIn 1st ICSE Workshop on Green and Sustainable Software Engineering, Zurich, Switzerland, 3rd June 2012 An Energy Consumption Model and Analysis Tool for Cloud Computing Environments FeiFei Chen, Jean

  16. Evaluation of the Daylight Cycle of Model-Predicted Cloud Amount and Condensed Water Path over Europe with Observations from MSG SEVIRI

    E-Print Network [OSTI]

    Stoffelen, Ad

    Evaluation of the Daylight Cycle of Model-Predicted Cloud Amount and Condensed Water Path over accurate information on diurnal cycles during daylight hours of cloud properties over land and ocean surfaces. This paper evaluates the daylight cycle of CA and CWP as predicted by the Regional Atmospheric

  17. Cloud Properties Working Group Low Clouds Update

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t zManufacturing:DOE NationalCommittee of

  18. Environmental representation and the role of clouds in studies and analysis models

    SciTech Connect (OSTI)

    Hummel, J.R.; Campbell, A.P.

    1997-10-01T23:59:59.000Z

    The Joint Analysis community is currently making significant improvements and enhancements to its suite of modeling tools used to support studies and analyses for Joint applications. This effort is being performed under the Joint Analytic Model Improvement Program (JAMIP) that began in 1995. One part of the JAMIP effort is the development of the Joint Warfare System (JWARS). JWARS will be a state of the art closed-form, constructive simulation of multisided, joint warefare for analysis. The environment will be a significant factor in future warefare analysis and so JWARS will include an authoritative environmental representation that can be represented at variable spatial and temporal scales. Argonne`s Dynamic Environmental Effects Model (DEEM) was used to provide the environmental representation for the JWARS prototype effort. In this paper we will present an overview of JWARS and describe how the environment and environmental effects are being represented in JWARS. Specific emphasis will be given on how clouds are included in the JWARS environment and the impacts they have on the warfighting functionality included in JWARS.

  19. Draft NISTIR 80061 NIST Cloud Computing2

    E-Print Network [OSTI]

    Draft NISTIR 80061 NIST Cloud Computing2 Forensic Science Challenges NIST Cloud Computing Forensic Computing11 Forensic Science Challenges 12 NIST Cloud Computing Forensic Science Working Group13 Information challenges77 faced by experts when responding to incidents that have occurred in a cloud-computing ecosystem

  20. AN INVESTIGATION OF THE TYPE M MORPHOLOGICAL STRUCTURE OF IC59: A NEW MODEL FOR BRIGHT RIM CLOUDS?

    SciTech Connect (OSTI)

    Miao Jingqi [Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NR (United Kingdom); Sugitani, Koji [Institute of Natural Sciences, Nagoya City University, Mizuho-ku, Nagoya 467-8501 (Japan); White, Glenn J. [Centre for Earth, Planetary, Space and Astronomical Research, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Nelson, Richard P., E-mail: J.Miao@kent.ac.u [School of Mathematical Sciences, Queen Mary College, University of London, Mile End Road, London E1 4NS (United Kingdom)

    2010-07-10T23:59:59.000Z

    We report the results from a smoothed particle hydrodynamics simulation designed to model recent observational data on the nebula and Bright Rim Cloud IC59. We further examine, in the context of radiative-driven implosion (RDI) models, the possible formation mechanisms of the morphological structure of IC59. The results of the simulation reveal the existence of a new, fourth morphological state for Bright Rim Clouds (BRCs)-which we propose to call a Type M BRC morphology. We discuss the necessary conditions for the appearance of Type M BRCs, based on analytical and numerical simulations. The simulated physical properties from our model are consistent with the available observations of IC59. We further show that the prospect of RDI triggered star formation in all Type M BRCs is not supported by the simulations.

  1. Transport Modeling Working Group Meeting Reports | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOriginEducationVideoStrategic|IndustrialCenter Gets PeopleTransmissionModeling Working Group

  2. CHEMICAL MODELING OF INFRARED DARK CLOUDS: THE ROLE OF SURFACE CHEMISTRY

    SciTech Connect (OSTI)

    Vasyunina, T.; Vasyunin, A. I.; Herbst, Eric [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States); Linz, H. [Max Planck Institute for Astronomy (MPIA), Koenigstuhl 17, D-69117 Heidelberg (Germany)

    2012-06-01T23:59:59.000Z

    We simulate the chemistry of infrared dark clouds (IRDCs) with a model in which the physical conditions are homogeneous and time independent. The chemistry is solved as a function of time with three networks: one purely gas phase, one that includes accretion and desorption, and one, the complete gas-grain network, that includes surface chemistry in addition. We compare our results with observed molecular abundances for two representative IRDCs-IRDC013.90-1 and IRDC321.73-1-using the molecular species N{sub 2}H{sup +}, HC{sub 3}N, HNC, HCO{sup +}, HCN, C{sub 2}H, NH{sub 3}, and CS. IRDC013.90-1 is a cold IRDC, with a temperature below 20 K, while IRDC321.73-1 is somewhat warmer, in the range 20-30 K. We find that the complete gas-grain model fits the data very well, but that the goodness of fit is not sharply peaked at a particular temperature. Surface processes are important for the explanation of the high gas-phase abundance of N{sub 2}H{sup +} in IRDC321.73-1. The general success of the zero-dimensional model in reproducing single-dish observations of our limited sample of eight species shows that it is probably sufficient for an explanation of this type of data. To build and justify more complicated models, including spatial temperature and density structure, contraction, and heating, we require high-resolution interferometric data.

  3. Cloud speed impact on solar variability scaling â?? Application to the wavelet variability model

    E-Print Network [OSTI]

    Lave, Matthew; Kleissl, Jan

    2013-01-01T23:59:59.000Z

    achieved over a solar power plant due to decorrelationmodel (WVM) for solar PV power plants. Sustainable Energy,solar PV power production is mostly caused by the movement of clouds across the PV plant.

  4. Application of Computational Fluid Dynamics in the Forced Dispersion Modeling of LNG Vapor Clouds

    E-Print Network [OSTI]

    Kim, Byung-Kyu

    2013-05-31T23:59:59.000Z

    The safety and security of liquefied natural gas (LNG) facilities has prompted the need for continued study of LNG mitigation systems. Water spray systems are widely recognized as an effective measure for dispersing LNG vapor clouds. Currently...

  5. Compact complex manifolds as models Main theorem Strongly minimal groups Higher rank groups Questions Groups in the theory of compact complex

    E-Print Network [OSTI]

    Scanlon, Thomas

    = {z U | f (z) = 0}. Definition The structure CCM is the multisorted structure having a sort M Questions Basic model theory of CCM · CCM eliminates quantifiers. Thomas Scanlon University of California theorem Strongly minimal groups Higher rank groups Questions Basic model theory of CCM · CCM eliminates

  6. Sensitivity of Remote Aerosol Distributions to Representation of Cloud-Aerosol Interactions in a Global Climate Model

    SciTech Connect (OSTI)

    Wang, Hailong; Easter, Richard C.; Rasch, Philip J.; Wang, Minghuai; Liu, Xiaohong; Ghan, Steven J.; Qian, Yun; Yoon, Jin-Ho; Ma, Po-Lun; Vinoj, V.

    2013-06-05T23:59:59.000Z

    Many global aerosol and climate models, including the widely used Community Atmosphere Model version 5 (CAM5), have large biases in predicting aerosols in remote regions such as upper troposphere and high latitudes. In this study, we conduct CAM5 sensitivity simulations to understand the role of key processes associated with aerosol transformation and wet removal affecting the vertical and horizontal long-range transport of aerosols to the remote regions. Improvements are made to processes that are currently not well represented in CAM5, which are guided by surface and aircraft measurements together with results from a multi-scale aerosol-climate model (PNNL-MMF) that explicitly represents convection and aerosol-cloud interactions at cloud-resolving scales. We pay particular attention to black carbon (BC) due to its importance in the Earth system and the availability of measurements. We introduce into CAM5 a new unified scheme for convective transport and aerosol wet removal with explicit aerosol activation above convective cloud base. This new implementation reduces the excessive BC aloft to better simulate observed BC profiles that show decreasing mixing ratios in the mid- to upper-troposphere. After implementing this new unified convective scheme, we examine wet removal of submicron aerosols that occurs primarily through cloud processes. The wet removal depends strongly on the sub-grid scale liquid cloud fraction and the rate of conversion of liquid water to precipitation. These processes lead to very strong wet removal of BC and other aerosols over mid- to high latitudes during winter months. With our improvements, the Arctic BC burden has a10-fold (5-fold) increase in the winter (summer) months, resulting in a much better simulation of the BC seasonal cycle as well. Arctic sulphate and other aerosol species also increase but to a lesser extent. An explicit treatment of BC aging with slower aging assumptions produces an additional 30-fold (5-fold) increase in the Arctic winter (summer) BC burden. This BC aging treatment, however, has minimal effect on other under-predicted species. Interestingly, our modifications to CAM5 that aim at improving prediction of high-latitude and upper tropospheric aerosols also produce much better AOD and AAOD over various other regions globally when compared to multi-year AERONET retrievals. The improved aerosol distributions have impacts on other aspects of CAM5, improving the simulation of global mean liquid water path and cloud forcing.

  7. Computing and Partitioning Cloud Feedbacks Using Cloud Property Histograms. Part I: Cloud Radiative Kernels

    E-Print Network [OSTI]

    Hartmann, Dennis

    radiative forcing. The global and annual mean model-simulated cloud feedback is dominated by contributions to a hypothetical cloudless but other- wise identical planet, the global and annual mean effect of clouds at the top is how cloud radiative effects will change as the planet warms because of long-lived greenhouse gases

  8. Superbubble evolution including the star-forming clouds: Is it possible to reconcile LMC observations with model predictions?

    E-Print Network [OSTI]

    S. Silich; J. Franco

    1999-05-13T23:59:59.000Z

    Here we present a possible solution to the apparent discrepancy between the observed properties of LMC bubbles and the standard, constant density bubble model. A two-dimensional model of a wind-driven bubble expanding from a flattened giant molecular cloud is examined. We conclude that the expansion velocities derived from spherically symmetric models are not always applicable to elongated young bubbles seen almost face-on due to the LMC orientation. In addition, an observational test to differentiate between spherical and elongated bubbles seen face-on is discussed.

  9. 3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds

    E-Print Network [OSTI]

    Forget, Francois; Millour, Ehouarn; Madeleine, Jean-Baptiste; Kerber, Laura; Leconte, Jeremy; Marcq, Emmanuel; Haberle, Robert M

    2012-01-01T23:59:59.000Z

    On the basis of geological evidence, it is often stated that the early martian climate was warm enough for liquid water to flow on the surface thanks to the greenhouse effect of a thick atmosphere. We present 3D global climate simulations of the early martian climate performed assuming a faint young sun and a CO2 atmosphere with pressure between 0.1 and 7 bars. The model includes a detailed radiative transfer model using revised CO2 gas collision induced absorption properties, and a parameterisation of the CO2 ice cloud microphysical and radiative properties. A wide range of possible climates is explored by using various values of obliquities, orbital parameters, cloud microphysic parameters, atmospheric dust loading, and surface properties. Unlike on present day Mars, for pressures higher than a fraction of a bar, surface temperatures vary with altitude because of the adiabatic cooling and warming of the atmosphere when it moves vertically. In most simulations, CO2 ice clouds cover a major part of the planet...

  10. Cloud Computing

    SciTech Connect (OSTI)

    Pete Beckman and Ian Foster

    2009-12-04T23:59:59.000Z

    Chicago Matters: Beyond Burnham (WTTW). Chicago has become a world center of "cloud computing." Argonne experts Pete Beckman and Ian Foster explain what "cloud computing" is and how you probably already use it on a daily basis.

  11. The Effects of Parceling on Testing Group Differences in Second-Order CFA Models: A Comparison between Multi-Group CFA and MIMIC Models

    E-Print Network [OSTI]

    Zou, Yuanyuan

    2010-10-12T23:59:59.000Z

    Using multi-group confirmatory factor analysis (MCFA) and multiple-indicator-multiple-cause (MIMIC) to investigate group difference in the context of the second-order factor model with either the unparceled or parceled data had never been thoroughly...

  12. Cross-Tenant Trust Models in Cloud Computing Bo Tang and Ravi Sandhu

    E-Print Network [OSTI]

    Sandhu, Ravi

    -tenancy which enables data and configuration segregation upon shared in- frastructures. Each tenant essentially to a cloud service provider (CSP). The consumer can unilaterally manage its data and settings through interfaces given by the CSP as well as its share of computing resources. The CSP is re- sponsible enforcing

  13. CGILS: Results from the First Phase of an International Project to Understand the Physical Mechanisms of Low Cloud Feedbacks in Single Column Models

    SciTech Connect (OSTI)

    Zhang, Minghua; Bretherton, Christopher S.; Blossey, Peter; Austin, Phillip A.; Bacmeister, J.; Bony, Sandrine; Brient, Florent; Cheedela, Suvarchal K.; Cheng, Anning; Del Genio, Anthony D.; De Roode, Stephan R.; Endo , Satoshi; Franklin, Charmaine N.; Golaz, Jean-Christophe; Hannay, Cecile; Heus, Thijs; Isotta, Francesco A.; Jean-Louis, Dufresne; Kang, In-Sik; Kawai, Hideaki; Koehler, M.; Larson, Vincent E.; Liu, Yangang; Lock, Adrian; Lohmann, U.; Khairoutdinov, Marat; Molod, Andrea M.; Neggers, Roel; Rasch, Philip J.; Sandu, Irina; Senkbeil, Ryan; Siebesma, A. P.; Siegenthaler-Le Drian, Colombe; Stevens, Bjorn; Suarez, Max; Xu, Kuan-Man; Von Salzen, Knut; Webb, Mark; Wolf, Audrey; Zhao, M.

    2013-12-26T23:59:59.000Z

    Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.

  14. pCloud: A Cloud-based Power Market Simulation Environment

    SciTech Connect (OSTI)

    Rudkevich, Aleksandr; Goldis, Evgeniy

    2012-12-02T23:59:59.000Z

    This research conducted by the Newton Energy Group, LLC (NEG) is dedicated to the development of pCloud: a Cloud-based Power Market Simulation Environment. pCloud is offering power industry stakeholders the capability to model electricity markets and is organized around the Software as a Service (SaaS) concept -- a software application delivery model in which software is centrally hosted and provided to many users via the internet. During the Phase I of this project NEG developed a prototype design for pCloud as a SaaS-based commercial service offering, system architecture supporting that design, ensured feasibility of key architecture's elements, formed technological partnerships and negotiated commercial agreements with partners, conducted market research and other related activities and secured funding for continue development of pCloud between the end of Phase I and beginning of Phase II, if awarded. Based on the results of Phase I activities, NEG has established that the development of a cloud-based power market simulation environment within the Windows Azure platform is technologically feasible, can be accomplished within the budget and timeframe available through the Phase II SBIR award with additional external funding. NEG believes that pCloud has the potential to become a game-changing technology for the modeling and analysis of electricity markets. This potential is due to the following critical advantages of pCloud over its competition: - Standardized access to advanced and proven power market simulators offered by third parties. - Automated parallelization of simulations and dynamic provisioning of computing resources on the cloud. This combination of automation and scalability dramatically reduces turn-around time while offering the capability to increase the number of analyzed scenarios by a factor of 10, 100 or even 1000. - Access to ready-to-use data and to cloud-based resources leading to a reduction in software, hardware, and IT costs. - Competitive pricing structure, which will make high-volume usage of simulation services affordable. - Availability and affordability of high quality power simulators, which presently only large corporate clients can afford, will level the playing field in developing regional energy policies, determining prudent cost recovery mechanisms and assuring just and reasonable rates to consumers. - Users that presently do not have the resources to internally maintain modeling capabilities will now be able to run simulations. This will invite more players into the industry, ultimately leading to more transparent and liquid power markets.

  15. A polar stratospheric cloud parameterization for the global modeling initiative three-dimensional model and its response to stratospheric aircraft

    SciTech Connect (OSTI)

    Considine, D. B. [Earth System Science Interdisciplinary Center and Department of Meteorology, University of Maryland, College Park (United States)] [Earth System Science Interdisciplinary Center and Department of Meteorology, University of Maryland, College Park (United States); Douglass, A. R. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)] [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States); Connell, P. S. [Lawrence Livermore National Laboratory, Livermore, California (United States)] [Lawrence Livermore National Laboratory, Livermore, California (United States); Kinnison, D. E. [Lawrence Livermore National Laboratory, Livermore, California (United States)] [Lawrence Livermore National Laboratory, Livermore, California (United States); Rotman, D. A. [Lawrence Livermore National Laboratory, Livermore, California (United States)] [Lawrence Livermore National Laboratory, Livermore, California (United States)

    2000-02-16T23:59:59.000Z

    We describe a new parameterization of polar stratospheric clouds (PSCs) which was written for and incorporated into the three-dimensional (3-D) chemistry and transport model (CTM) developed for NASA's Atmospheric Effects of Aviation Project (AEAP) by the Global Modeling Initiative (GMI). The parameterization was designed to respond to changes in NO{sub y} and H{sub 2}O produced by high-speed civilian transport (HSCT) emissions. The parameterization predicts surface area densities (SADs) of both Type 1 and Type 2 PSCs for use in heterogeneous chemistry calculations. Type 1 PSCs are assumed to have a supercooled ternary sulfate (STS) composition, and Type 2 PSCs are treated as water ice with a coexisting nitric acid trihydrate (NAT) phase. Sedimentation is treated by assuming that the PSC particles obey lognormal size distributions, resulting in a realistic mass flux of condensed phase H{sub 2}O and HNO{sub 3}. We examine a simulation of the Southern Hemisphere high-latitude lower stratosphere winter and spring seasons driven by temperature and wind fields from a modified version of the National Center for Atmospheric Research (NCAR) Middle Atmosphere Community Climate Model Version 2 (MACCM2). Predicted PSC SADs and median radii for both Type 1 and Type 2 PSCs are consistent with observations. Gas phase HNO{sub 3} and H{sub 2}O concentrations in the high-latitude lower stratosphere qualitatively agree with Cryogenic Limb Array Etalon Spectrometer (CLAES) HNO{sub 3} and Microwave Limb Sounder (MLS) H{sub 2}O observations. The residual denitrification and dehydration of the model polar vortex after polar winter compares well with atmospheric trace molecule spectroscopy (ATMOS) observations taken during November 1994. When the NO{sub x} and H{sub 2}O emissions of a standard 500-aircraft HSCT fleet with a NO{sub x} emission index of 5 are added, NO{sub x} and H{sub 2}O concentrations in the Southern Hemisphere polar vortex before winter increase by up to 3%. This results in earlier onset of PSC formation, denitrification, and dehydration. Active Cl{sub y} increases and produces small ({approx}1%) decreases in lower stratospheric vortex O{sub 3} concentrations during the spring relative to the HSCT-free run. (c) 2000 American Geophysical Union.

  16. Investigation of the Dynamical, Macrophysical and Radiative Properties of High Clouds Combining Satellite Observations and Climate Model Simulations

    E-Print Network [OSTI]

    Li, Yue

    2012-02-14T23:59:59.000Z

    This dissertation investigates three topics concerning high clouds: 1) convectively coupled equatorial wave (CCEW) signals derived from cloud top temperature (CTT) and cirrus optical thickness retrieved from satellite observations; 2) investigation...

  17. Regional Model Simulations of Marine Boundary Layer Clouds over the Southeast Pacific off South America. Part I: Control Experiment

    E-Print Network [OSTI]

    Xie, Shang-Ping

    . Globally, cloud reflectivity increases the earth's albedo with a net effect to cool the earth climateCaa and Bretherton 2003). In addition to these local effects, the cloud- top longwave radiation cools the MBL sea surface temperature (SST), but also by cloud-radiation feedback. A heat budget analysis indicates

  18. Dust in brown dwarfs and extra-solar planets IV. Assessing TiO2 and SiO nucleation for cloud formation modeling

    E-Print Network [OSTI]

    Lee, G; Giles, H; Bromley, S T

    2014-01-01T23:59:59.000Z

    Clouds form in atmospheres of brown dwarfs and planets. The cloud particle formation processes are similar to the dust formation process studied in circumstellar shells of AGB stars and in Supernovae. Cloud formation modelling in substellar objects requires gravitational settling and element replenishment in addition to element depletion. All processes depend on the local conditions, and a simultaneous treatment is required. We apply new material data in order to assess our cloud formation model results regarding the treatment of the formation of condensation seeds. We re-address the question of the primary nucleation species in view of new (TiO2)_N-cluster data and new SiO vapour pressure data. We apply the density functional theory using the computational chemistry package Gaussian 09 to derive updated thermodynamical data for (TiO2)_N-clusters as input for our TiO2 seed formation model. We test different nucleation treatments and their effect on the overall cloud structure by solving a system of dust momen...

  19. Interactive physically-based cloud simulation

    E-Print Network [OSTI]

    Overby, Derek Robert

    2002-01-01T23:59:59.000Z

    of digital artistic media. Previous methods for modeling the growth of clouds do not account for the fluid interactions that are responsible for cloud formation in the physical atmosphere. We propose a model for simulating cloud formation based on a basic...

  20. 6, 93519388, 2006 Aerosol-cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al Chemistry and Physics Discussions Aerosol-cloud interaction inferred from MODIS satellite data and global 6, 9351­9388, 2006 Aerosol-cloud interaction inferred from MODIS and models G. Myhre et al. Title

  1. Aerosol Indirect Effect on the Grid-scale Clouds in the Two-way Coupled WRF-CMAQ: Model Description, Development, Evaluation and Regional Analysis

    SciTech Connect (OSTI)

    Yu, Shaocai; Mathur, Rohit; Pleim, Jonathan; Wong, David; Gilliam, R.; Alapaty, Kiran; Zhao, Chun; Liu, Xiaohong

    2014-10-24T23:59:59.000Z

    This study implemented first, second and glaciations aerosol indirect effects (AIE) on resolved clouds in the two-way coupled WRF-CMAQ modeling system by including parameterizations for both cloud drop and ice number concentrations on the basis of CMAQpredicted aerosol distributions and WRF meteorological conditions. The performance of the newly-developed WRF-CMAQ model, with alternate CAM and RRTMG radiation schemes, was evaluated with the observations from the CERES satellite and surface monitoring networks (AQS, IMPROVE, CASTNet, STN, and PRISM) over the continental U.S. (CONUS) (12-km resolution) and eastern Texas (4-km resolution) during August and September of 2006. The results at the AQS surface sites show that in August, the NMB values for PM2.5 over the eastern/western U.S (EUS/WUS) and western U.S. (WUS) are 5.3% (?0.1%) and 0.4% (-5.2%) for WRF-CMAQ/CAM (WRF-CMAQ/RRTMG), respectively. The evaluation of PM2.5 chemical composition reveals that in August, WRF-CMAQ/CAM (WRF-CMAQ/RRTMG) consistently underestimated the observed SO4 2? by -23.0% (-27.7%), -12.5% (-18.9%) and -7.9% (-14.8%) over the EUS at the CASTNet, IMPROVE and STN sites, respectively. Both models (WRF-CMAQ/CAM, WRF-CMAQ/RRTMG) overestimated the observed mean OC, EC and TC concentrations over the EUS in August at the IMPROVE sites. Both models generally underestimated the cloud field (SWCF) over the CONUS in August due to the fact that the AIE on the subgrid convective clouds was not considered when the model simulations were run at the 12 km resolution. This is in agreement with the fact that both models captured SWCF and LWCF very well for the 4-km simulation over the eastern Texas when all clouds were resolved by the finer domain. Both models generally overestimated the observed precipitation by more than 40% mainly because of significant overestimation in the southern part of the CONUS in August. The simulations of WRF-CMAQ/CAM and WRF-CMAQ/RRTMG show dramatic improvements for SWCF, LWCF, COD, cloud fractions and precipitation over the ocean relative to those of WRF default cases in August. The model performance in September is similar to that in August except for greater overestimation of PM2.5 due to the overestimations of SO4 2-, NH4 +, NO3 -, and TC over the EUS, less underestimation of clouds (SWCF) over the land areas due to about 10% lower SWCF values and less convective clouds in September.

  2. Effect of Subgrid Cloud Variability on Parameterization of Indirect Aerosol Effect in Large-Scale Models

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEA :Work4/11ComputationalEdNERSC:Effect of Subgrid Cloud

  3. Evaluation of Long-Term Cloud-Resolving Modeling with ARM Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1, 13Evacuation EmergencyCloudSat,Evaluation of

  4. Development of Distributed Programming Developing Tool-Kit Based on Object Group Model

    E-Print Network [OSTI]

    Joo, Su-Chong

    Development of Distributed Programming Developing Tool-Kit Based on Object Group Model Jeong of the grouped distributed objects[10-14], as a logical unit of distributed application service, and developed a distributed programming developing tool-kit based on object group model(OGM-DPD Tool-Kit). This Tool- Kit can

  5. Combustion Group Group members

    E-Print Network [OSTI]

    Wang, Wei

    Combustion Group Group members: Thierry Poinsot, Emilien Courtine, Luc Vervisch, Benjamin Farcy 2014 #12;Combustion Group Combustion Physics and Modeling Pollutants, Emissions, and Soot Formation Thermoacoustics and Combustion Dynamics Research focus § Examine mechanisms responsible for flame stabilization

  6. A Low-order Model of Water Vapor, Clouds, and Thermal Emission for Tidally Locked Terrestrial Planets

    E-Print Network [OSTI]

    Yang, Jun

    2014-01-01T23:59:59.000Z

    In the spirit of minimal modeling of complex systems, we develop an idealized two-column model to investigate the climate of tidally locked terrestrial planets with Earth-like atmospheres in the habitable zone of M-dwarf stars. The model is able to approximate the fundamental features of the climate obtained from three-dimensional (3D) atmospheric general circulation model (GCM) simulations. One important reason for the two-column model's success is that it reproduces the high cloud albedo of the GCM simulations, which reduces the planet's temperature and delays the onset of a runaway greenhouse state. The two-column model also clearly illustrates a secondary mechanism for determining the climate: the nightside acts as a ``radiator fin'' through which infrared energy can be lost to space easily. This radiator fin is maintained by a temperature inversion and dry air on the nightside, and plays a similar role to the subtropics on modern Earth. Since 1D radiative-convective models cannot capture the effects of t...

  7. Experiments and Models Bearing on the Role of Chromite as a Collector of Platinum Group

    E-Print Network [OSTI]

    Mcdonough, William F.

    Experiments and Models Bearing on the Role of Chromite as a Collector of Platinum Group Minerals PUBLICATION SEPTEMBER 6, 2008 Chromite is widely recognized to act as a collector for platinum group elements

  8. The Evolution of Cloud Computing in ATLAS

    E-Print Network [OSTI]

    Taylor, Ryan P.; The ATLAS collaboration; Love, Peter; Leblanc, Matthew Edgar; Di Girolamo, Alessandro; Paterson, Michael; Gable, Ian; Sobie, Randall; Field, Laurence

    2015-01-01T23:59:59.000Z

    The ATLAS experiment has successfully incorporated cloud computing technology and cloud resources into its primarily grid-based model of distributed computing. Cloud R&D activities continue to mature and transition into stable production systems, while ongoing evolutionary changes are still needed to adapt and refine the approaches used, in response to changes in prevailing cloud technology. In addition, completely new developments are needed to handle emerging requirements. This work will describe the overall evolution of cloud computing in ATLAS. The current status of the VM management systems used for harnessing IAAS resources will be discussed. Monitoring and accounting systems tailored for clouds are needed to complete the integration of cloud resources within ATLAS' distributed computing framework. We are developing and deploying new solutions to address the challenge of operation in a geographically distributed multi-cloud scenario, including a system for managing VM images across multiple clouds, ...

  9. Securely Managing Cryptographic Keys used within a Cloud Environment

    E-Print Network [OSTI]

    , Co-tenancy, Distributed Management Cryptography essential to secure cloud operations Use of sound;Page 3 Cloud Service Provider (CSP) - Models Cloud Service Models Software as a Service (Saa CSP know who I am? How is my connection to cloud components protected? Administration Who

  10. Explorations in combining cognitive models of individuals and system dynamics models of groups.

    SciTech Connect (OSTI)

    Backus, George A.

    2008-07-01T23:59:59.000Z

    This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

  11. Evaluation of convection-permitting model simulations of cloud populations associated with the Madden-Julian Oscillation using data collected during the AMIE/DYNAMO field campaign

    SciTech Connect (OSTI)

    Hagos, Samson M.; Feng, Zhe; Burleyson, Casey D.; Lim, Kyo-Sun; Long, Charles N.; Wu, Di; Thompson, Gregory

    2014-11-12T23:59:59.000Z

    Regional cloud permitting model simulations of cloud populations observed during the 2011 ARM Madden Julian Oscillation Investigation Experiment/ Dynamics of Madden-Julian Experiment (AMIE/DYNAMO) field campaign are evaluated against radar and ship-based measurements. Sensitivity of model simulated surface rain rate statistics to parameters and parameterization of hydrometeor sizes in five commonly used WRF microphysics schemes are examined. It is shown that at 2 km grid spacing, the model generally overestimates rain rate from large and deep convective cores. Sensitivity runs involving variation of parameters that affect rain drop or ice particle size distribution (more aggressive break-up process etc) generally reduce the bias in rain-rate and boundary layer temperature statistics as the smaller particles become more vulnerable to evaporation. Furthermore significant improvement in the convective rain-rate statistics is observed when the horizontal grid-spacing is reduced to 1 km and 0.5 km, while it is worsened when run at 4 km grid spacing as increased turbulence enhances evaporation. The results suggest modulation of evaporation processes, through parameterization of turbulent mixing and break-up of hydrometeors may provide a potential avenue for correcting cloud statistics and associated boundary layer temperature biases in regional and global cloud permitting model simulations.

  12. Evaluation of Cloud-resolving and Limited Area Model Intercomparison Simulations using TWP-ICE Observations. Part 2: Rain Microphysics

    SciTech Connect (OSTI)

    Varble, Adam; Zipser, Edward J.; Fridlind, Ann; Zhu, Ping; Ackerman, Andrew; Chaboureau, Jean-Pierre; Fan, Jiwen; Hill, Adrian; Shipway, Ben; Williams, Christopher R.

    2014-12-27T23:59:59.000Z

    Ten 3D cloud-resolving model (CRM) simulations and four 3D limited area model (LAM) simulations of an intense mesoscale convective system observed on January 23-24, 2006 during the Tropical Warm Pool – International Cloud Experiment (TWP-ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, co-located UHF and VHF vertical profilers, and a Joss-Waldvogel disdrometer in an attempt to explain published results showing a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One-moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rain water contents (RWCs) that are similar to observed. Two-moment rain schemes with a gamma shape parameter (?) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one-moment schemes, but lower RWCs than observed. Two moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and thus, may have issues balancing raindrop formation, collision coalescence, and raindrop breakup. Assuming a ? of 2.5 rather than 0 for the raindrop size distribution improves one-moment scheme biases, and allowing ? to have values greater than 0 may improve two-moment schemes. Under-predicted stratiform rain rates are associated with under-predicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. In addition to stronger convective updrafts than observed, limited domain size prevents a large, well-developed stratiform region from developing in CRMs, while a dry bias in ECMWF analyses does the same to the LAMs.

  13. Dynamics of Clouds Fall Semester 2012

    E-Print Network [OSTI]

    ATS712 Dynamics of Clouds Fall Semester 2012 Meeting Times: T/Th: 9-10:15am Room: ATS 101-2pm Course Description: This class focuses on the general dynamics of cloud systems. Models of fog and other Tools / Skills Cotton, W.R., G.H. Bryan, and S.C. van den Heever, 2010: Storm and Cloud Dynamics

  14. Group classification of a nonlinear sound wave model

    E-Print Network [OSTI]

    J. C. Ndogmo

    2008-06-26T23:59:59.000Z

    Based on a recent classification of subalgebras of the symmetry algebra of the Zabolotskaya-Khokhlov equation, all similarity reductions of this equation into ordinary differential equations are obtained. Large classes of group invariant solutions of the equation are also determined, and some properties of these solutions are discussed.

  15. Final Report for "Improved Representations of Cloud Microphysics for Model and Remote Sensing Evaluation using Data Collected during ISDAC, TWP-ICE and RACORO

    SciTech Connect (OSTI)

    McFarquhar, Greg M. [University of Illinois] University of Illinois

    2003-06-11T23:59:59.000Z

    We were funded by ASR to use data collected during ISDAC and TWP-ICE to evaluate models with a variety of temporal and spatial scales, to evaluate ground-based remote sensing retrievals and to develop cloud parameterizations with the end goal of improving the modeling of cloud processes and properties and their impact on atmospheric radiation. In particular, we proposed to: 1) Calculate distributions of microphysical properties observed in arctic stratus during ISDAC for initializing and evaluating LES and GCMs, and for developing parameterizations of effective particle sizes, mean fall velocities, and mean single-scattering properties for such models; 2) Improve representations of particle sizes, fall velocities and scattering properties for tropical and arctic cirrus using TWP-ICE, ISDAC and M-PACE data, and to determine the contributions that small ice crystals, with maximum dimensions D less than 50 ?m, make to mass and radiative properties; 3) Study fundamental interactions between clouds and radiation by improving representations of small quasi-spherical particles and their scattering properties. We were additionally funded 1-year by ASR to use RACORO data to develop an integrated product of cloud microphysical properties. We accomplished all of our goals.

  16. Modeling Individual and Group Actions in Meetings: a Two-Layer HMM Framework

    E-Print Network [OSTI]

    Wrigley, Stuart

    of eight group actions, using a pub- lic five-hour meeting corpus. Experiments and comparison with a singleModeling Individual and Group Actions in Meetings: a Two-Layer HMM Framework Dong Zhang, Daniel. The investigated patterns are in- herently group-based (defined by the individual activities of meeting

  17. Physica D 159 (2001) 3557 Wave group dynamics in weakly nonlinear long-wave models

    E-Print Network [OSTI]

    Pelinovsky, Dmitry

    Physica D 159 (2001) 35­57 Wave group dynamics in weakly nonlinear long-wave models Roger Grimshawa Communicated by A.C. Newell Abstract The dynamics of wave groups is studied for long waves, using the framework reserved. Keywords: Wave group dynamics; Korteweg­de Vries equation; Nonlinear Schr¨odinger equation 1

  18. Evaluating cloud retrieval algorithms with the ARM BBHRP framework

    SciTech Connect (OSTI)

    Mlawer,E.; Dunn,M.; Mlawer, E.; Shippert, T.; Troyan, D.; Johnson, K. L.; Miller, M. A.; Delamere, J.; Turner, D. D.; Jensen, M. P.; Flynn, C.; Shupe, M.; Comstock, J.; Long, C. N.; Clough, S. T.; Sivaraman, C.; Khaiyer, M.; Xie, S.; Rutan, D.; Minnis, P.

    2008-03-10T23:59:59.000Z

    Climate and weather prediction models require accurate calculations of vertical profiles of radiative heating. Although heating rate calculations cannot be directly validated due to the lack of corresponding observations, surface and top-of-atmosphere measurements can indirectly establish the quality of computed heating rates through validation of the calculated irradiances at the atmospheric boundaries. The ARM Broadband Heating Rate Profile (BBHRP) project, a collaboration of all the working groups in the program, was designed with these heating rate validations as a key objective. Given the large dependence of radiative heating rates on cloud properties, a critical component of BBHRP radiative closure analyses has been the evaluation of cloud microphysical retrieval algorithms. This evaluation is an important step in establishing the necessary confidence in the continuous profiles of computed radiative heating rates produced by BBHRP at the ARM Climate Research Facility (ACRF) sites that are needed for modeling studies. This poster details the continued effort to evaluate cloud property retrieval algorithms within the BBHRP framework, a key focus of the project this year. A requirement for the computation of accurate heating rate profiles is a robust cloud microphysical product that captures the occurrence, height, and phase of clouds above each ACRF site. Various approaches to retrieve the microphysical properties of liquid, ice, and mixed-phase clouds have been processed in BBHRP for the ACRF Southern Great Plains (SGP) and the North Slope of Alaska (NSA) sites. These retrieval methods span a range of assumptions concerning the parameterization of cloud location, particle density, size, shape, and involve different measurement sources. We will present the radiative closure results from several different retrieval approaches for the SGP site, including those from Microbase, the current 'reference' retrieval approach in BBHRP. At the NSA, mixed-phase clouds and cloud with a low optical depth are prevalent; the radiative closure studies using Microbase demonstrated significant residuals. As an alternative to Microbase at NSA, the Shupe-Turner cloud property retrieval algorithm, aimed at improving the partitioning of cloud phase and incorporating more constrained, conditional microphysics retrievals, also has been evaluated using the BBHRP data set.

  19. Global cloud liquid water path simulations

    SciTech Connect (OSTI)

    Lemus, L. [Southern Hemisphere Meteorology, Clayton, Victoria (Australia)] [Southern Hemisphere Meteorology, Clayton, Victoria (Australia); Rikus, L. [Bureau of Meteorology Research Centre, Melbourne, Victoria (Australia)] [Bureau of Meteorology Research Centre, Melbourne, Victoria (Australia); Martin, C.; Platt, R. [CSIRO, Aspendale, Victoria (Australia)] [CSIRO, Aspendale, Victoria (Australia)

    1997-01-01T23:59:59.000Z

    A new parameterization of cloud liquid water and ice content has been included in the Bureau of Meteorology Global Assimilation and Prediction System. The cloud liquid water content is derived from the mean cloud temperatures in the model using an empirical relationship based on observations. The results from perpetual January and July simulations are presented and show that the total cloud water path steadily decreases toward high latitudes, with two relative maxima at midlatitudes and a peak at low latitudes. To validate the scheme, the simulated fields need to be processed to produce liquid water paths that can be directly compared with the corresponding field derived from Special Sensor Microwave/Imager (SSM/I) data. This requires the identification of cloud ice water content within the parameterization and a prescription to account for the treatment of strongly precipitating subgrid-scale cloud. The resultant cloud liquid water paths agree qualitatively with the SSM/I data but show some systematic errors that are attributed to corresponding errors in the model`s simulation of cloud amounts. Given that a more quantitative validation requires substantial improvement in the model`s diagnostic cloud scheme, the comparison with the SSM/I data indicates that the cloud water path, derived from the cloud liquid water content parameterization introduced in this paper, is consistent with the observations and can be usefully incorporated in the prediction system. 40 refs., 11 figs., 1 tab.

  20. Using Simulation to Model and Understand Group Learning Maartje Spoelstra1,2

    E-Print Network [OSTI]

    Sklar, Elizabeth

    Using Simulation to Model and Understand Group Learning Maartje Spoelstra1,2 and Elizabeth Sklar3 1 to construct computational models that act as controllers for agents acting in a simulated learning en-invasive experiments on the design of learning environments. Keywords: multi-agent simulation, education, group

  1. An exploration of the stages of change model in a group treatment program for male batterers

    E-Print Network [OSTI]

    Wells, Robert Davis

    2005-02-17T23:59:59.000Z

    in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2004 Major Subject: Counseling Psychology AN EXPLORATION OF THE STAGES OF CHANGE MODEL IN A GROUP TREATMENT PROGRAM...) __________________________ Michael R. Benz (Head of Department) December 2004 Major Subject: Counseling Psychology iii ABSTRACT An Exploration of the Stages of Change Model in a Group Treatment Program for Male Batterers. (December 2004...

  2. Model Assessment with Renormalization Group in Statistical Learning

    E-Print Network [OSTI]

    GingQuo, Wang

    2013-01-01T23:59:59.000Z

    Clustering: 50 years beyond K-means,” Pattern Recognitionas Fig. 2a). Perform the k-means clustering algorithm, whichThe coarse set and model. The k-means clustering algorithm—

  3. Investigation of Microphysical Parameterizations of Snow and Ice in Arctic Clouds during M-PACE through ModelObservation Comparisons

    E-Print Network [OSTI]

    Solomon, Amy

    Investigation of Microphysical Parameterizations of Snow and Ice in Arctic Clouds during M the microphysical properties of Arctic mixed-phase stratocumulus. Intensive measurements taken during the Department of Energy Atmospheric Radiation Measurement Program Mixed-Phase Arctic Cloud Experiment (M

  4. Using a cloud resolving model to generate the beam-filling correction for microwave retrieval of oceanic rainfall

    E-Print Network [OSTI]

    Feng, Kai

    2003-01-01T23:59:59.000Z

    ), respectively. They have a parameterized two-class liquid water (cloud water and rain) and a parameterized three-class ice-phase scheme (cloud ice, snow, and graupel). A tropical squall line has been observed on 29 August 1999 during the Kwajalein Experiment...

  5. The Evolution of Cloud Computing in ATLAS

    E-Print Network [OSTI]

    Taylor, Ryan P; The ATLAS collaboration; Brasolin, Franco; Cordeiro, Cristovao; Desmarais, Ron; Field, Laurence; Gable, Ian; Giordano, Domenico; Di Girolamo, Alessandro; Hover, John; Leblanc, Matthew Edgar; Love, Peter; Paterson, Michael; Sobie, Randall; Zaytsev, Alexandr

    2015-01-01T23:59:59.000Z

    The ATLAS experiment has successfully incorporated cloud computing technology and cloud resources into its primarily grid-based model of distributed computing. Cloud R&D activities continue to mature and transition into stable production systems, while ongoing evolutionary changes are still needed to adapt and refine the approaches used, in response to changes in prevailing cloud technology. In addition, completely new developments are needed to handle emerging requirements. This paper describes the overall evolution of cloud computing in ATLAS. The current status of the virtual machine (VM) management systems used for harnessing infrastructure as a service (IaaS) resources are discussed. Monitoring and accounting systems tailored for clouds are needed to complete the integration of cloud resources within ATLAS' distributed computing framework. We are developing and deploying new solutions to address the challenge of operation in a geographically distributed multi-cloud scenario, including a system for ma...

  6. Final Technical Report for "Ice nuclei relation to aerosol properties: Data analysis and model parameterization for IN in mixed-phase clouds"Ă?Âť (DOE/SC00002354)

    SciTech Connect (OSTI)

    Paul J. DeMott, Anthony J. Prenni; Sonia M. Kreidenweis

    2012-09-28T23:59:59.000Z

    Clouds play an important role in weather and climate. In addition to their key role in the hydrologic cycle, clouds scatter incoming solar radiation and trap infrared radiation from the surface and lower atmosphere. Despite their importance, feedbacks involving clouds remain as one of the largest sources of uncertainty in climate models. To better simulate cloud processes requires better characterization of cloud microphysical processes, which can affect the spatial extent, optical depth and lifetime of clouds. To this end, we developed a new parameterization to be used in numerical models that describes the variation of ice nuclei (IN) number concentrations active to form ice crystals in mixed-phase (water droplets and ice crystals co-existing) cloud conditions as these depend on existing aerosol properties and temperature. The parameterization is based on data collected using the Colorado State University continuous flow diffusion chamber in aircraft and ground-based campaigns over a 14-year period, including data from the DOE-supported Mixed-Phase Arctic Cloud Experiment. The resulting relationship is shown to more accurately represent the variability of ice nuclei distributions in the atmosphere compared to currently used parameterizations based on temperature alone. When implemented in one global climate model, the new parameterization predicted more realistic annually averaged cloud water and ice distributions, and cloud radiative properties, especially for sensitive higher latitude mixed-phase cloud regions. As a test of the new global IN scheme, it was compared to independent data collected during the 2008 DOE-sponsored Indirect and Semi-Direct Aerosol Campaign (ISDAC). Good agreement with this new data set suggests the broad applicability of the new scheme for describing general (non-chemically specific) aerosol influences on IN number concentrations feeding mixed-phase Arctic stratus clouds. Finally, the parameterization was implemented into a regional cloud-resolving model to compare predictions of ice crystal concentrations and other cloud properties to those observed in two intensive case studies of Arctic stratus during ISDAC. Our implementation included development of a prognostic scheme of ice activation using the IN parameterization so that the most realistic treatment of ice nuclei, including their budget (gains and losses), was achieved. Many cloud microphysical properties and cloud persistence were faithfully reproduced, despite a tendency to under-predict (by a few to several times) ice crystal number concentrations and cloud ice mass, in agreement with some other studies. This work serves generally as the basis for improving predictive schemes for cloud ice crystal activation in cloud and climate models, and more specifically as the basis for such a scheme to be used in a Multi-scale Modeling Format (MMF) that utilizes a connected system of cloud-resolving models on a global grid in an effort to better resolve cloud processes and their influence on climate.

  7. Cloud Computing Adam Barker

    E-Print Network [OSTI]

    St Andrews, University of

    Cloud Computing 1 Adam Barker #12;Overview · Introduction to Cloud computing · Enabling technologies · Di erent types of cloud: IaaS, PaaS and SaaS · Cloud terminology · Interacting with a cloud: management consoles · Launching an instance · Connecting to an instance · Running your application · Clouds

  8. CME THEORY AND MODELS Report of Working Group D

    E-Print Network [OSTI]

    California at Berkeley, University of

    , USA 10Department of Physical Sciences, University of Helsinki, Helsinki, Finland (Author contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can corona into the advectively dominated solar wind. The section on evolution and propagation presents two

  9. NIST Cloud Computing Strategy working paper, April 2011 1 of 25 NIST Strategy to build a USG Cloud Computing

    E-Print Network [OSTI]

    NIST Cloud Computing Strategy working paper, April 2011 1 of 25 NIST Strategy to build a USG Cloud of United States Government (USG) secure and effective adoption of the Cloud Computing2 model to reduce costs and improve services. The working document describes the NIST Cloud Computing program efforts

  10. Satellite-based remote sensing of cirrus clouds: hyperspectral radiative transfer modeling, analysis of uncertainties in in-situ cloud extinction measurements and intercomparison of cirrus retrievals from a-train instruments

    E-Print Network [OSTI]

    Zhang, Zhibo

    2009-05-15T23:59:59.000Z

    of uncertainties in the FSSP (Forward Scattering Spectrometer Probe) measurement of cloud extinction by small ice particles. First, the single-scattering properties of small ice particles in cirrus clouds are derived and compared to those of equivalent spheres...

  11. Lecture Ch. 8 Cloud Classification

    E-Print Network [OSTI]

    Russell, Lynn

    clouds Middle clouds Grayish, block the sun, sometimes patchy Sharp outlines, rising, bright white1 Lecture Ch. 8 · Cloud Classification ­ Descriptive approach to clouds · Drop Growth and Precipitation Processes ­ Microphysical characterization of clouds · Complex (i.e. Real) Clouds ­ Examples

  12. An Actor-Centric, Asset-Based Monitor Deployment Model for Cloud Computing Uttam Thakore, Gabriel A. Weaver, and William H. Sanders

    E-Print Network [OSTI]

    Sanders, William H.

    -Champaign Urbana, Illinois 61801 {thakore1, gweaver, whs}@illinois.edu Abstract--Effective monitoring is essential roles: Cloud Provider (CP), Cloud Service Provider (CSP), and Cloud Service Consumer (CSC) [3], [4 that is run through its cloud offering. The Cloud Service Provider (CSP) is the user of a CP but is also

  13. Application of Computational Fluid Dynamics in the Forced Dispersion Modeling of LNG Vapor Clouds 

    E-Print Network [OSTI]

    Kim, Byung-Kyu

    2013-05-31T23:59:59.000Z

    droplet-LNG vapor system, which will serve in developing guidelines and establishing engineering criteria for a site-specific LNG mitigation system. Finally, the potentials of applying CFD modeling in providing guidance for setting up the design criteria...

  14. Study of Ice Cloud Properties from Synergetic Use of Satellite Observations and Modeling Capabilities 

    E-Print Network [OSTI]

    Xie, Yu

    2011-02-22T23:59:59.000Z

    -12 hexagonal plates. The scattering properties of an individual aggregate ice particle are computed using the discrete dipole approximation or an Improved Geometric Optics Method, depending upon the size parameter. The aggregate model provides an accurate...

  15. Investigation of Thin Cirrus Cloud Optical and Microphysical Properties on the Basis of Satellite Observations and Fast Radiative Transfer Models

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

    This dissertation focuses on the global investigation of optically thin cirrus cloud optical thickness (tau) and microphysical properties, such as, effective particle size (D_(eff)) and ice crystal habits (shapes), based on the global satellite...

  16. Investigations of cloud altering effects of atmospheric aerosols using a new mixed Eulerian-Lagrangian aerosol model

    E-Print Network [OSTI]

    Steele, Henry Donnan, 1974-

    2004-01-01T23:59:59.000Z

    Industry, urban development, and other anthropogenic influences have substantially altered the composition and size-distribution of atmospheric aerosol particles over the last century. This, in turn, has altered cloud ...

  17. Cloud Security by Max Garvey

    E-Print Network [OSTI]

    Tolmach, Andrew

    Cloud Security Survey by Max Garvey #12;Cloudy Cloud is Cloudy What is the cloud? On Demand Service Network access Resource pooling Elasticity of Resources Measured Service #12;Cloud Types/Variants Iaa Cloud Public Cloud Hybrid Cloud combination. Private cloud with overflow going to public cloud. #12

  18. Variational Bayesian image restoration with group-sparse modeling of wavelet coefficients

    E-Print Network [OSTI]

    Zhang, Ganchi; Kingsbury, Nick

    2015-05-07T23:59:59.000Z

    In this work, we present a recent wavelet-based image restoration framework based on a group-sparse Gaussian scale mixture model. A hierarchical Bayesian estimation is derived using a combination of variational Bayesian inference and a subband...

  19. Representation of Clouds and Precipitation Processes in the Community Atmosphere Model (CAM3)

    E-Print Network [OSTI]

    and the Community Climate Model (CCM3) are summarized. Parameterization changes between CCM3 and CAM2 introduced and the tropical tropopause temperature are used to diagnose the impact of the changes between CCM3 and CAM2 the large scale environment in CCM3 and CAM2. The convective parameterizations are not easily modified

  20. The Shell Model, the Renormalization Group and the Two-Body Interaction

    E-Print Network [OSTI]

    B. K. Jennings

    2005-04-25T23:59:59.000Z

    The no-core shell model and the effective interaction $V_{{\\rm low} k}$ can both be derived using the Lee-Suzuki projection operator formalism. The main difference between the two is the choice of basis states that define the model space. The effective interaction $V_{{\\rm low} k}$ can also be derived using the renormalization group. That renormalization group derivation can be extended in a straight forward manner to also include the no-core shell model. In the nuclear matter limit the no-core shell model effective interaction in the two-body approximation reduces identically to $V_{{\\rm low} k}$. The same considerations apply to the Bloch-Horowitz version of the shell model and the renormalization group treatment of two-body scattering by Birse, McGovern and Richardson.

  1. MISR Cloud Detection over Ice and Snow Based on Linear Correlation Matching

    E-Print Network [OSTI]

    Sekhon, Jasjeet S.

    MISR Cloud Detection over Ice and Snow Based on Linear Correlation Matching Tao Shi , Bin Yu , and Amy Braverman Abstract Cloud detection is a crucial step in any climate modelling or prediction data to retrieve or estimate the cloud height and hence cloud detection. However, cloud detection even

  2. VALIDATION OF CLOUD LIQUID WATER PATH RETRIEVALS FROM SEVIRI ON METEOSAT-8 USING CLOUDNET OBSERVATIONS

    E-Print Network [OSTI]

    Haak, Hein

    on global cloud statistics and radiation budget #12;(Feijt et al., 2003). With the launch of Meteosat Second effective radius and Cloud Liquid Water Path (CLWP) over Europe. The CloudNET research project, supported forecast models. The radiative behavior of clouds depends predominantly on cloud properties

  3. Diagnosis of the Marine Low Cloud Simulation in the NCAR Community Earth System Model (CESM) and the NCEP Global Forecast System (GFS)-Modular Ocean Model v4 (MOM4) coupled model

    SciTech Connect (OSTI)

    Xiao, Heng; Mechoso, C. R.; Sun, Rui; Han, J.; Pan, H. L.; Park, S.; Hannay, Cecile; Bretherton, Christopher S.; Teixeira, J.

    2014-07-25T23:59:59.000Z

    We present a diagnostic analysis of the marine low cloud climatology simulated by two state-of-the-art coupled atmosphere-ocean models: the NCAR Community Earth System Model (CESM) and the NCEP Global Forecasting System (GFS). In both models, the shallow convection and boundary layer turbulence parameterizations have been recently updated: both models now use a mass-flux scheme for the parameterization of shallow convection, and a turbulence parameterization capable of handling Stratocumulus (Sc)-topped Planetary Boundary Layers (PBLs). For shallow convection, both models employ a convective trigger function based on the concept of convective inhibition and both include explicit convective overshooting/penetrative entrainment formulation. For Sc-topped PBL, both models treat explicitly turbulence mixing and cloud-top entrainment driven by cloud-top radiative cooling. Our focus is on the climatological transition from Sc to shallow Cumulus (Cu)-topped PBL in the subtropical eastern oceans. We show that in the CESM the coastal Sc-topped PBLs in the subtropical Eastern Pacific are well-simulated but the climatological transition from Sc to shallow Cu is too abrupt and happens too close to the coast. By contrast, in the GFS coupled simulation the coastal Sc amount and PBL depth are severely underestimated while the transition from Sc to shallow Cu is łdelayed˛ and offshore Sc cover is too extensive in the subtropical Eastern Pacific. We discuss the possible connections between such differences in the simulations and differences in the parameterizations of shallow convection and boundary layer turbulence in the two models.

  4. A few-group delayed neutron model based on a consistent set of decay constants

    SciTech Connect (OSTI)

    Campbell, J.M.; Spriggs, G.D.

    1998-01-22T23:59:59.000Z

    As part of an international effort, the Los Alamos National Laboratory has been asked to (1) determine if there is a set of dominant precursors that are common to all fissionable isotopes and all incident neutron energies, (2) expand the existing experimentally-measured few-group models commonly used in the nuclear industry into their 8-group equivalent using a consistent set of decay constants corresponding to these dominant precursors, and (3) formulate new group spectra for the equivalent 8-group model. In response to this request, LANL has calculated the theoretical delayed neutron yield for 14 different isotopes using three different incident neutron spectra (i.e., thermal, fast, and 14.1 MeV) using the current fission-yield and emission probability data found in ENDF-VI. An example of these results is shown in a figure in which the theoretical delayed neutron yields for the 271 precursors produced during thermal fission of {sup 235}U are plotted against the half-lives of the precursors. By comparing the results of all 14 isotopes, a preliminary set of precursors has been identified that are dominant within the various half-life regimes of the delayed neutron precursors. Also plotted on a figure are the group yields of the 8-group equivalent model of Keepin`s 6-group model. And finally, an example of the delayed neutron spectra for group 7 in the 8-group equivalent model is shown. A final report summarizing all results is expected to be released for review by the international steering committee by the summer of 1998.

  5. Cloud Computing og availability

    E-Print Network [OSTI]

    Christensen, Henrik Bćrbak

    Cloud Computing og availability Projekt i pĺlidelighed Henrik Lavdal - 20010210 Sřren Bardino Kaa - 20011654 Gruppe 8 19-03-2010 #12;Cloud Computing og availability Side 2 af 28 Indholdsfortegnelse as a Service (SaaS) ...................................................................9 Availability i cloud

  6. Effects of Pre-Existing Ice Crystals on Cirrus Clouds and Comparison between Different Ice Nucleation Parameterizations with the Community Atmosphere Model (CAM5)

    SciTech Connect (OSTI)

    Shi, Xiangjun; Liu, Xiaohong; Zhang, Kai

    2015-01-01T23:59:59.000Z

    In order to improve the treatment of ice nucleation in a more realistic manner in the Community Atmospheric Model version 5.3 (CAM5.3), the effects of preexisting ice crystals on ice nucleation in cirrus clouds are considered. In addition, by considering the in-cloud variability in ice saturation ratio, homogeneous nucleation takes place spatially only in a portion of cirrus cloud rather than in the whole area of cirrus cloud. With these improvements, the two unphysical limiters used in the representation of ice nucleation are removed. Compared to observations, the ice number concentrations and the probability distributions of ice number concentration are both improved with the updated treatment. The preexisting ice crystals significantly reduce ice number concentrations in cirrus clouds, especially at mid- to high latitudes in the upper troposphere (by a factor of ~10). Furthermore, the contribution of heterogeneous ice nucleation to cirrus ice crystal number increases considerably.Besides the default ice nucleation parameterization of Liu and Penner (2005, hereafter LP) in CAM5.3, two other ice nucleation parameterizations of Barahona and Nenes (2009, hereafter BN) and Kärcher et al. (2006, hereafter KL) are implemented in CAM5.3 for the comparison. In-cloud ice crystal number concentration, percentage contribution from heterogeneous ice nucleation to total ice crystal number, and preexisting ice effects simulated by the three ice nucleation parameterizations have similar patterns in the simulations with present-day aerosol emissions. However, the change (present-day minus pre-industrial times) in global annual mean column ice number concentration from the KL parameterization (3.24×106 m-2) is obviously less than that from the LP (8.46×106 m-2) and BN (5.62×106 m-2) parameterizations. As a result, experiment using the KL parameterization predicts a much smaller anthropogenic aerosol longwave indirect forcing (0.24 W m-2) than that using the LP (0.46 W m-2) and BN (0.39 W m-2) parameterizations.

  7. Enlarged Transformation Group: Star Models,Dark Matter Halos and Solar System Dynamics

    E-Print Network [OSTI]

    Edward Lee Green

    2014-07-25T23:59:59.000Z

    Previously a theory has been presented which extends the geometrical structure of a real four-dimensional space-time via a field of orthonormal tetrads with an enlarged transformation group. This new transformation group, called the conservation group, contains the group of diffeomorphisms as a proper subgroup and we hypothesize that it is the foundational group for quantum geometry. The fundamental geometric object of the new geometry is the curvature vector, C^\\mu . Using the scalar Lagrangian density C^\\mu C_\\mu \\sqrt{-g}, field equations for the free field have been obtained which are invariant under the conservation group. In this paper, this theory is further extended by development of a suitable Lagrangian for a field with sources. Spherically symmetric solutions for both the free field and the field with sources are given. A stellar model and an external, free-field model are developed. The theory implies that the external stress-energy tensor has non-compact support and hence may give the geometrical foundation for dark matter. The resulting models are compared to the internal and external Schwarzschild models. The theory may explain the Pioneer anomaly and the corona heating problem.

  8. Comparing generic models for interplanetary shocks and magnetic clouds axis configurations at 1 AU

    E-Print Network [OSTI]

    Janvier, Miho; Demoulin, Pascal; Masias-Meza, Jimmy; Lugaz, Noe

    2015-01-01T23:59:59.000Z

    Interplanetary Coronal Mass Ejections are the manifestation of solar transient eruptions, which can significantly modify the plasma and magnetic conditions in the heliosphere. They are often preceded by a shock, and a magnetic flux rope is detected in situ in a third to half of them. The main aim of this study is to obtain the best quantitative shape for the flux rope axis and for the shock surface from in situ data obtained during spacecraft crossings of these structures. We first compare the orientation of the flux ropes axes and shock normals obtained from independent data analyses of the same events, observed in situ at 1AU from the Sun. Then, we carry out an original statistical analysis of axes/shock normals by deriving the statistical distributions of their orientations. We fit the observed distributions using the distributions derived from several synthetic models describing these shapes. We show that the distributions of axis/shock orientations are very sensitive to their respective shape. One classi...

  9. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS, VOL. ???, XXXX, DOI:10.1029/, Low cloud reduction in a greenhouse-warmed1

    E-Print Network [OSTI]

    Bretherton, Chris

    -30 son is that the global radiative effect of boundary-layer clouds is an aggregate over many31 large cloud reduction, and they com-11 bine to weaken shortwave cloud radiative effect by over 50%. Large-scale circulation regimes, but the `dynamic' effect of circulation shifts on clouds32 largely cancel out on global

  10. Study of ice cloud properties using infrared spectral data

    E-Print Network [OSTI]

    Garrett, Kevin James

    2009-05-15T23:59:59.000Z

    The research presented in this thesis involves the study of ice cloud microphysical and optical properties using both hyperspectral and narrowband infrared spectral data. First, ice cloud models are developed for the Infrared Atmospheric Sounding...

  11. Study of ice cloud properties using infrared spectral data 

    E-Print Network [OSTI]

    Garrett, Kevin James

    2009-05-15T23:59:59.000Z

    The research presented in this thesis involves the study of ice cloud microphysical and optical properties using both hyperspectral and narrowband infrared spectral data. First, ice cloud models are developed for the Infrared Atmospheric Sounding...

  12. arctic cloud experiment: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    low-level Arctic clouds in cold seasons and have a significant impact on the surface energy budget. However, the treatment of mixed-phase clouds in most current climate models...

  13. On Demand Surveillance Service in Vehicular Cloud

    E-Print Network [OSTI]

    Weng, Jui-Ting

    2013-01-01T23:59:59.000Z

    Toward Vehicular Service Cloud . . . . . . . . . . . . . . .4.2 Open Mobile Cloud Requirement . . . . .3.1 Mobile Cloud

  14. Final Technical Report on Scaling Models of the Internal Variability of Clouds DoE Grant No. DE-FG02-04ER63773

    SciTech Connect (OSTI)

    Ivanova, Kristinka

    2008-04-24T23:59:59.000Z

    The purpose of this proposal is to gain a better understanding of the space-time correlations of atmospheric fluctuations in clouds through application of methods from statistical physics to high resolution, continuous data sets of cloud observations available at the Department of Energy Atmospheric Radiation Measurement Program archive. In this report we present the accomplishments achieved during the four year period. Starting with the most recent one, we report on two break-throughs in our research that make the fourth year of the project exceptionally successful and markedly outperforming the objectives. The first break-through is on characterization of the structure of cirrus radiative properties at large, intermediate and small, generating cells scales by applying the Fokker-Planck equation method and other methods to ARM millimeter wavelength radar observations collected at the Southern Great Plains site. The second break-through is that we show that different characterizations of the cirrus radiative properties are obtained for different synoptic scale environments. We outline a stochastic approach to investigate the internal structure of radiative properties of cirrus clouds based on empirical modeling and draw conclusions about cirrus dynamical properties in the context of the synoptic environment. Results on the structure of cirrus dynamical properties are consistent with the structure of cirrus based on aircraft in situ measurements, with results from ground-based Raman lidar, and with results from model studies. These achievements would not have been possible without the accomplishments from the previous years on a number of problems that involve application of methods of analysis such as the Fokker-Planck equation approach, Tsallis nonextensive statistical mechanics, detrended fluctuation analysis, and others. These include stochastic analysis of neutrally stratified cirrus layers, internal variability and turbulence in cirrus, dynamical model and nonextensive statistical mechanics of liquid water path fluctuations, etc.

  15. Utilizing CLASIC observations and multiscale models to study the impact of improved Land surface representation on modeling cloud- convection

    SciTech Connect (OSTI)

    Niyogi, Devdutta S. [Purdue

    2013-06-07T23:59:59.000Z

    The CLASIC experiment was conducted over the US southern great plains (SGP) in June 2007 with an objective to lead an enhanced understanding of the cumulus convection particularly as it relates to land surface conditions. This project was design to help assist with understanding the overall improvement of land atmosphere convection initiation representation of which is important for global and regional models. The study helped address one of the critical documented deficiency in the models central to the ARM objectives for cumulus convection initiation and particularly under summer time conditions. This project was guided by the scientific question building on the CLASIC theme questions: What is the effect of improved land surface representation on the ability of coupled models to simulate cumulus and convection initiation? The focus was on the US Southern Great Plains region. Since the CLASIC period was anomalously wet the strategy has been to use other periods and domains to develop the comparative assessment for the CLASIC data period, and to understand the mechanisms of the anomalous wet conditions on the tropical systems and convection over land. The data periods include the IHOP 2002 field experiment that was over roughly same domain as the CLASIC in the SGP, and some of the DOE funded Ameriflux datasets.

  16. Cloud computing models

    E-Print Network [OSTI]

    Gorelik, Eugene

    2013-01-01T23:59:59.000Z

    Information Technology has always been considered a major pain point of enterprise organizations, from the perspectives of both cost and management. However, the information technology industry has experienced a dramatic ...

  17. Cloud Computing For Bioinformatics

    E-Print Network [OSTI]

    Ferrara, Katherine W.

    Cloud Computing For Bioinformatics EC2 and AMIs #12;Quick-starting an EC2 instance (let's get our feet wet!) Cloud Computing #12;Cloud Computing: EC2 instance Quick Start · On EC2 console, we can click on Launch Instance · This will let us get up and going quickly #12;Cloud Computing: EC2 instance

  18. Determinating Timing Channels in Statistically Multiplexed Clouds

    E-Print Network [OSTI]

    Aviram, Amittai; Ford, Bryan; Gummadi, Ramakrishna

    2010-01-01T23:59:59.000Z

    Timing side-channels represent an insidious security challenge for cloud computing, because: (a) they enable one customer to steal information from another without leaving a trail or raising alarms; (b) only the cloud provider can feasibly detect and report such attacks, but the provider's incentives are not to; and (c) known general-purpose timing channel control methods undermine statistical resource sharing efficiency, and, with it, the cloud computing business model. We propose a new cloud architecture that uses provider-enforced deterministic execution to eliminate all timing channels internal to a shared cloud domain, without limiting internal resource sharing. A prototype determinism-enforcing hypervisor demonstrates that utilizing such a cloud might be both convenient and efficient. The hypervisor enables parallel guest processes and threads to interact via familiar shared memory and file system abstractions, and runs moderately coarse-grained parallel tasks as efficiently and scalably as current nond...

  19. Exploiting Processor Groups to Extend Scalability of the GA Shared Memory Programming Model

    SciTech Connect (OSTI)

    Nieplocha, Jarek; Krishnan, Manoj Kumar; Palmer, Bruce J.; Tipparaju, Vinod; Zhang, Yeliang

    2005-05-04T23:59:59.000Z

    Exploiting processor groups is becoming increasingly important for programming next-generation high-end systems composed of tens or hundreds of thousands of processors. This paper discusses the requirements, functionality and development of multilevel-parallelism based on processor groups in the context of the Global Array (GA) shared memory programming model. The main effort involves management of shared data, rather than interprocessor communication. Experimental results for the NAS NPB Conjugate Gradient benchmark and a molecular dynamics (MD) application are presented for a Linux cluster with Myrinet and illustrate the value of the proposed approach for improving scalability. While the original GA version of the CG benchmark lagged MPI, the processor-group version outperforms MPI in all cases, except for a few points on the smallest problem size. Similarly, the group version of the MD application improves execution time by 58% on 32 processors.

  20. A HEART CELL GROUP MODEL FOR THE IDENTIFICATION OF MYOCARDIAL ISCHEMIA

    E-Print Network [OSTI]

    Povinelli, Richard J.

    A HEART CELL GROUP MODEL FOR THE IDENTIFICATION OF MYOCARDIAL ISCHEMIA Mohamed A. Mneimneh, Micheal signal are an indicator for ischemia. For this purpose, this work proposes an approach based on a heart of 75.66%. 1 INTRODUCTION Ischemic heart disease is the leading cause of death in the world with almost

  1. Reflector modelling of small high leakage cores making use of multi-group nodal equivalence theory

    SciTech Connect (OSTI)

    Theron, S. A. [South African Nuclear Energy Corporation (Necsa), PO Box 582, Pretoria, 0001 (South Africa); Reitsma, F. [Calvera Consultants, PO Box 150, Strubensvallei, 1735 (South Africa)

    2012-07-01T23:59:59.000Z

    This research focuses on modelling reflectors in typical material testing reactors (MTRs). Equivalence theory is used to homogenise and collapse detailed transport solutions to generate equivalent nodal parameters and albedo boundary conditions for reflectors, for subsequent use in full core nodal diffusion codes. This approach to reflector modelling has been shown to be accurate for two-group large commercial light water reactor (LWR) analysis, but has not been investigated for MTRs. MTRs are smaller, with much larger leakage, environment sensitivity and multi-group spectrum dependencies than LWRs. This study aims to determine if this approach to reflector modelling is an accurate and plausible homogenisation technique for the modelling of small MTR cores. The successful implementation will result in simplified core models, better accuracy and improved efficiency of computer simulations. Codes used in this study include SCALE 6.1, OSCAR-4 and EQUIVA (the last two codes are developed and used at Necsa). The results show a five times reduction in calculational time for the proposed reduced reactor model compared to the traditional explicit model. The calculated equivalent parameters however show some sensitivity to the environment used to generate them. Differences in the results compared to the current explicit model, require more careful investigation including comparisons with a reference result, before its implementation can be recommended. (authors)

  2. Cluster analysis of cloud properties : a method for diagnosing cloud-climate feedbacks

    E-Print Network [OSTI]

    Gordon, Neil D.

    2008-01-01T23:59:59.000Z

    to temperature. Thus a k-means clustering algorithm is usedto group cloud regimes. K-means is also an effective toollays out a method whereby a k-means clustering algorithm is

  3. A Sensitivity Study of Radiative Fluxes at the Top of Atmosphere to Cloud-Microphysics and Aerosol Parameters in the Community Atmosphere Model CAM5

    SciTech Connect (OSTI)

    Zhao, Chun; Liu, Xiaohong; Qian, Yun; Yoon, Jin-Ho; Hou, Zhangshuan; Lin, Guang; McFarlane, Sally A.; Wang, Hailong; Yang, Ben; Ma, Po-Lun; Yan, Huiping; Bao, Jie

    2013-11-08T23:59:59.000Z

    In this study, we investigated the sensitivity of net radiative fluxes (FNET) at the top of atmosphere (TOA) to 16 selected uncertain parameters mainly related to the cloud microphysics and aerosol schemes in the Community Atmosphere Model version 5 (CAM5). We adopted a quasi-Monte Carlo (QMC) sampling approach to effectively explore the high dimensional parameter space. The output response variables (e.g., FNET) were simulated using CAM5 for each parameter set, and then evaluated using generalized linear model analysis. In response to the perturbations of these 16 parameters, the CAM5-simulated global annual mean FNET ranges from -9.8 to 3.5 W m-2 compared to the CAM5-simulated FNET of 1.9 W m-2 with the default parameter values. Variance-based sensitivity analysis was conducted to show the relative contributions of individual parameter perturbation to the global FNET variance. The results indicate that the changes in the global mean FNET are dominated by those of cloud forcing (CF) within the parameter ranges being investigated. The size threshold parameter related to auto-conversion of cloud ice to snow is confirmed as one of the most influential parameters for FNET in the CAM5 simulation. The strong heterogeneous geographic distribution of FNET variation shows parameters have a clear localized effect over regions where they are acting. However, some parameters also have non-local impacts on FNET variance. Although external factors, such as perturbations of anthropogenic and natural emissions, largely affect FNET variations at the regional scale, their impact is weaker than that of model internal parameters in terms of simulating global mean FNET in this study. The interactions among the 16 selected parameters contribute a relatively small portion of the total FNET variations over most regions of the globe. This study helps us better understand the CAM5 model behavior associated with parameter uncertainties, which will aid the next step of reducing model uncertainty via calibration of uncertain model parameters with the largest sensitivity.

  4. Interstellar Turbulence, Cloud Formation and Pressure Balance

    E-Print Network [OSTI]

    Enrique Vazquez-Semadeni

    1998-10-23T23:59:59.000Z

    We discuss HD and MHD compressible turbulence as a cloud-forming and cloud-structuring mechanism in the ISM. Results from a numerical model of the turbulent ISM at large scales suggest that the phase-like appearance of the medium, the typical values of the densities and magnetic field strengths in the intercloud medium, as well as Larson's velocity dispersion-size scaling relation in clouds may be understood as consequences of the interstellar turbulence. However, the density-size relation appears to only hold for the densest simulated clouds, there existing a large population of small, low-density clouds, which, on the other hand, are hardest to observe. We then discuss several tests and implications of a fully dynamical picture of interstellar clouds. The results imply that clouds are transient, constantly being formed, distorted and disrupted by the turbulent velocity field, with a fraction of these fluctuations undergoing gravitational collapse. Simulated line profiles and estimated cloud lifetimes are consistent with observational data. In this scenario, we suggest it is quite unlikely that quasi-hydrostatic structures on any scale can form, and that the near pressure balance between clouds and the intercloud medium is an incidental consequence of the density field driven by the turbulence and in the presence of appropriate cooling, rather than a driving or confining mechanism.

  5. A New Two-Moment Bulk Stratiform Cloud Microphysics Scheme in the Community Atmosphere Model, Version 3 (CAM3). Part II: Single-Column and Global Results

    E-Print Network [OSTI]

    Gettelman, Andrew

    on climate by modifying the cloud radiative properties, that is, indirect aerosol effects (Twomey 1977 as the hydrological cycle. Thus, clouds are critical in maintaining the global energy balance. For example change (Bony et al. 2006). The effects of aerosols on cloud particles may also have a significant impact

  6. Ignition of Aluminum Particles and Clouds

    SciTech Connect (OSTI)

    Kuhl, A L; Boiko, V M

    2010-04-07T23:59:59.000Z

    Here we review experimental data and models of the ignition of aluminum (Al) particles and clouds in explosion fields. The review considers: (i) ignition temperatures measured for single Al particles in torch experiments; (ii) thermal explosion models of the ignition of single Al particles; and (iii) the unsteady ignition Al particles clouds in reflected shock environments. These are used to develop an empirical ignition model appropriate for numerical simulations of Al particle combustion in shock dispersed fuel explosions.

  7. Renormalization Group Analysis of Finite-Size Scaling in the $?^4_4$ Model

    E-Print Network [OSTI]

    R. Kenna; C. B. Lang

    1992-10-08T23:59:59.000Z

    A finite-size scaling theory for the $\\phi^4_4$ model is derived using renormalization group methods. Particular attention is paid to the partition function zeroes, in terms of which all thermodynamic observables can be expressed. While the leading scaling behaviour is identical to that of mean field theory, there exist multiplicative logarithmic corrections too. A non-perturbative test of these formulae in the form of a high precision Monte Carlo analysis reveals good quantitative agreement with the analytical predictions.

  8. Tensor renormalization group study of the 2d O(3) model

    E-Print Network [OSTI]

    Judah Unmuth-Yockey; Yannick Meurice; James Osborn; Haiyuan Zou

    2014-11-16T23:59:59.000Z

    We present our progress on a study of the $O(3)$ model in two-dimensions using the Tensor Renormalization Group method. We first construct the theory in terms of tensors, and show how to construct $n$-point correlation functions. We then give results for thermodynamic quantities at finite and infinite volume, as well as 2-point correlation function data. We discuss some of the advantages and challenges of tensor renormalization and future directions in which to work.

  9. Renormalization group running of neutrino parameters in the inverse seesaw model

    E-Print Network [OSTI]

    Johannes Bergstrom; Michal Malinsky; Tommy Ohlsson; He Zhang

    2012-07-06T23:59:59.000Z

    We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.

  10. Renormalization group running of neutrino parameters in the inverse seesaw model

    SciTech Connect (OSTI)

    Bergstroem, Johannes; Malinsky, Michal; Ohlsson, Tommy; Zhang He [Department of Theoretical Physics, School of Engineering Sciences, Royal Institute of Technology (KTH)-AlbaNova University Center, Roslagstullsbacken 21, 106 91 Stockholm (Sweden)

    2010-06-01T23:59:59.000Z

    We perform a detailed study of the renormalization group equations in the inverse seesaw model. Especially, we derive compact analytical formulas for the running of the neutrino parameters in the standard model and the minimal supersymmetric standard model, and illustrate that, due to large Yukawa coupling corrections, significant running effects on the leptonic mixing angles can be naturally obtained in the proximity of the electroweak scale, perhaps even within the reach of the LHC. In general, if the mass spectrum of the light neutrinos is nearly degenerate, the running effects are enhanced to experimentally accessible levels, well suitable for the investigation of the underlying dynamics behind the neutrino mass generation and the lepton flavor structure. In addition, the effects of the seesaw thresholds are discussed, and a brief comparison to other seesaw models is carried out.

  11. Cell model of in-cloud scavenging of highly soluble gases Alexander Baklanov a,b,n

    E-Print Network [OSTI]

    Elperin, Tov

    of fully online integrated atmospheric chemistry and meteorology models and Earth system models requires

  12. RISK ASSESSMENT CLOUD COMPUTING

    E-Print Network [OSTI]

    Columbia University

    SECURITY RESEARCH PRIVACY RISK ASSESSMENT AMC DATA FISMA CLOUD COMPUTING MOBILE DEVICES OPERATIONS application hosted in the cloud · Alaska DHHS fined $1.7M ­ Portable device stolen from vehicle · Mass Eye

  13. Using Radar, Lidar, and Radiometer measurements to Classify Cloud Type and Study Middle-Level Cloud Properties

    SciTech Connect (OSTI)

    Wang, Zhien

    2010-06-29T23:59:59.000Z

    The project is mainly focused on the characterization of cloud macrophysical and microphysical properties, especially for mixed-phased clouds and middle level ice clouds by combining radar, lidar, and radiometer measurements available from the ACRF sites. First, an advanced mixed-phase cloud retrieval algorithm will be developed to cover all mixed-phase clouds observed at the ACRF NSA site. The algorithm will be applied to the ACRF NSA observations to generate a long-term arctic mixed-phase cloud product for model validations and arctic mixed-phase cloud processes studies. To improve the representation of arctic mixed-phase clouds in GCMs, an advanced understanding of mixed-phase cloud processes is needed. By combining retrieved mixed-phase cloud microphysical properties with in situ data and large-scale meteorological data, the project aim to better understand the generations of ice crystals in supercooled water clouds, the maintenance mechanisms of the arctic mixed-phase clouds, and their connections with large-scale dynamics. The project will try to develop a new retrieval algorithm to study more complex mixed-phase clouds observed at the ACRF SGP site. Compared with optically thin ice clouds, optically thick middle level ice clouds are less studied because of limited available tools. The project will develop a new two wavelength radar technique for optically thick ice cloud study at SGP site by combining the MMCR with the W-band radar measurements. With this new algorithm, the SGP site will have a better capability to study all ice clouds. Another area of the proposal is to generate long-term cloud type classification product for the multiple ACRF sites. The cloud type classification product will not only facilitates the generation of the integrated cloud product by applying different retrieval algorithms to different types of clouds operationally, but will also support other research to better understand cloud properties and to validate model simulations. The ultimate goal is to improve our cloud classification algorithm into a VAP.

  14. Aircraft induced cirrus cloud First year report

    E-Print Network [OSTI]

    Oxford, University of

    and coagulation. A resulting size distribution of ice crystals is deemed indicative of contrail cirrus cloud model operates, simulating the life cycle of aerosol and ice particles: nucleation, condensation

  15. Global simulations of ice nucleation and ice supersaturation with an improved cloud scheme in the Community

    E-Print Network [OSTI]

    Gettelman, Andrew

    and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloud are sensitive to the parameterization of ice clouds. These results indicate that ice clouds are potentiallyGlobal simulations of ice nucleation and ice supersaturation with an improved cloud scheme

  16. Polar Cloud Detection using Satellite Data with Analysis and Application of Kernel Learning Algorithms

    E-Print Network [OSTI]

    Shi, Tao

    Abstract Polar Cloud Detection using Satellite Data with Analysis and Application of Kernel Professor Bin Yu, Chair Clouds play a major role in Earth's climate and cloud detection is a crucial step climate model studies. Cloud detection is particularly difficult in the snow- and ice-covered polar

  17. Cloud Detection over Snow and Ice Using MISR Data , Eugene E. Clothiaux

    E-Print Network [OSTI]

    Yu, Bin

    Cloud Detection over Snow and Ice Using MISR Data Tao Shi , Bin Yu , Eugene E. Clothiaux , and Amy J. Braverman Abstract Clouds play a major role in Earth's climate and cloud detection prediction and global climate model studies. To advance the observational capabilities of detecting clouds

  18. CLOUD FRACTION: CAN IT BE DEFINED, CAN IT BE MEASURED, AND IF WE KNEW IT

    E-Print Network [OSTI]

    Schwartz, Stephen E.

    droplets and/or ice particles in the atmosphere above the earth's surface. Total cloud cover: Fraction, JGR (ERBE, 1988) Cloud cover is a loosely defined term. Potter Stewart (U.S. Supreme Court, 1964) I feedbacks. Accurate representation of cloud radiative effects is essential in climate models. Getting cloud

  19. Cloud Properties Working Group Break Out Session

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t zManufacturing:DOE NationalCommittee of thePresence

  20. ARM Cloud Properties Working Group: Meeting Logistics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP Update Information on new, existing, and futureAn

  1. XSEDE Cloud Survey Report

    E-Print Network [OSTI]

    Walter, M.Todd

    XSEDE Cloud Survey Report David Lifka, Cornell Center for Advanced Computing Ian Foster, ANL, ANL and The University of Chicago A National Science Foundation-sponsored cloud user survey was conducted from September 2012 to April 2013 by the XSEDE Cloud Integration Investigation Team to better

  2. Research Cloud Computing Recommendations

    E-Print Network [OSTI]

    Qian, Ning

    Research Cloud Computing Recommendations SRCPAC December 3, 2014 #12;Mandate and Membership SRCPAC convened this committee in Sept 2014 to investigate the role that cloud computing should play in our & Academic Affairs (Social Work) #12;Questions discussed · What cloud resources are available? · Which kinds

  3. Final Technical Report for Project "Improving the Simulation of Arctic Clouds in CCSM3"

    SciTech Connect (OSTI)

    Stephen J. Vavrus

    2008-11-15T23:59:59.000Z

    This project has focused on the simulation of Arctic clouds in CCSM3 and how the modeled cloud amount (and climate) can be improved substantially by altering the parameterized low cloud fraction. The new formula, dubbed 'freeezedry', alleviates the bias of excessive low clouds during polar winter by reducing the cloud amount under very dry conditions. During winter, freezedry decreases the low cloud amount over the coldest regions in high latitudes by over 50% locally and more than 30% averaged across the Arctic (Fig. 1). The cloud reduction causes an Arctic-wide drop of 15 W m{sup -2} in surface cloud radiative forcing (CRF) during winter and about a 50% decrease in mean annual Arctic CRF. Consequently, wintertime surface temperatures fall by up to 4 K on land and 2-8 K over the Arctic Ocean, thus significantly reducing the model's pronounced warm bias (Fig. 1). While improving the polar climate simulation in CCSM3, freezedry has virtually no influence outside of very cold regions (Fig. 2) or during summer (Fig. 3), which are space and time domains that were not targeted. Furthermore, the simplicity of this parameterization allows it to be readily incorporated into other GCMs, many of which also suffer from excessive wintertime polar cloudiness, based on the results from the CMIP3 archive (Vavrus et al., 2008). Freezedry also affects CCSM3's sensitivity to greenhouse forcing. In a transient-CO{sub 2} experiment, the model version with freezedry warms up to 20% less in the North Polar and South Polar regions (1.5 K and 0.5 K smaller warming, respectively) (Fig. 4). Paradoxically, the muted high-latitude response occurs despite a much larger increase in cloud amount with freezedry during non-summer months (when clouds warm the surface), apparently because of the colder modern reference climate. These results of the freezedry parameterization have recently been published (Vavrus and D. Waliser, 2008: An improved parameterization for simulating Arctic cloud amount in the CCSM3 climate model. J. Climate, 21, 5673-5687.). The article also provides a novel synthesis of surface- and satellite-based Arctic cloud observations that show how much the new freezedry parameterization improves the simulated cloud amount in high latitudes (Fig. 3). Freezedry has been incorporated into the CCSM3.5 version, in which it successfully limits the excessive polar clouds, and may be used in CCSM4. Material from this work is also appearing in a synthesis article on future Arctic cloud changes (Vavrus, D. Waliser, J. Francis, and A. Schweiger, 'Simulations of 20th and 21st century Arctic cloud amount in the global climate models assessed in the IPCC AR4', accepted in Climate Dynamics) and was used in a collaborative paper on Arctic cloud-sea ice coupling (Schweiger, A., R. Lindsay, S. Vavrus, and J. Francis, 2008: Relationships between Arctic sea ice and clouds during autumn. J. Climate, 21, 4799-4810.). This research was presented at the 2007 CCSM Annual Workshop, as well as the CCSM's 2007 Atmospheric Model Working Group and Polar Working Group Meetings. The findings were also shown at the 2007 Climate Change Prediction Program's Science Team Meeting. In addition, I served as an instructor at the International Arctic Research Center's (IARC) Summer School on Arctic Climate Modeling in Fairbanks this summer, where I presented on the challenges and techniques used in simulating polar clouds. I also contributed to the development of a new Arctic System Model by attending a workshop in Colorado this summer on this fledgling project. Finally, an outreach activity for the general public has been the development of an interactive web site (model/visualization/ipcc/>) that displays Arctic cloud amount in the CMIP3 climate model archive under present and future scenarios. This site allows users to make polar and global maps of a variety of climate variables to investigate the individual and ensemble-mean GCM response to greenhouse warming and the extent to which models adequately represent Arctic clouds in the modern clima

  4. A General Systems Theory for Rain Formation in Warm Clouds

    E-Print Network [OSTI]

    A. M. Selvam

    2014-08-15T23:59:59.000Z

    A cumulus cloud model which can explain the observed characteristics of warm rain formation in monsoon clouds is presented. The model is based on classical statistical physical concepts and satisfies the principle of maximum entropy production. Atmospheric flows exhibit selfsimilar fractal fluctuations that are ubiquitous to all dynamical systems in nature, such as physical, chemical, social, etc and are characterized by inverse power law form for power (eddy energy) spectrum signifying long-range space-time correlations. A general systems theory model for atmospheric flows developed by the author is based on the concept that the large eddy energy is the integrated mean of enclosed turbulent (small scale) eddies. This model gives scale-free universal governing equations for cloud growth processes. The model predicted cloud parameters are in agreement with reported observations, in particular, the cloud dropsize distribution. Rain formation can occur in warm clouds within 30minutes lifetime under favourable conditions of moisture supply in the environment.

  5. Natural Limits of Electroweak Model as Contraction of its Gauge Group

    E-Print Network [OSTI]

    Nikolay A. Gromov

    2014-10-31T23:59:59.000Z

    The low and higher energy limits of the Electroweak Model are obtained from first principles of gauge theory. Both limits are given by the same contraction of the gauge group, but for the different consistent rescalings of the field space. Mathematical contraction parameter in both cases is interpreted as energy. The very weak neutrino-matter interactions is explained by zero tending contraction parameter, which depend on neutrino energy. The second consistent rescaling corresponds to the higher energy limit of the Electroweak Model. At the infinite energy all particles lose masses, electroweak interactions become long-range and are mediated by the neutral currents. The limit model represents the development of the early Universe from the Big Bang up to the end of the first second.

  6. Acoustic clouds: standing sound waves around a black hole analogue

    E-Print Network [OSTI]

    Carolina L. Benone; Luis C. B. Crispino; Carlos Herdeiro; Eugen Radu

    2015-01-28T23:59:59.000Z

    Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.

  7. Acoustic clouds: standing sound waves around a black hole analogue

    E-Print Network [OSTI]

    Benone, Carolina L; Herdeiro, Carlos; Radu, Eugen

    2014-01-01T23:59:59.000Z

    Under certain conditions sound waves in fluids experience an acoustic horizon with analogue properties to those of a black hole event horizon. In particular, a draining bathtub-like model can give rise to a rotating acoustic horizon and hence a rotating black hole (acoustic) analogue. We show that sound waves, when enclosed in a cylindrical cavity, can form stationary waves around such rotating acoustic black holes. These acoustic perturbations display similar properties to the scalar clouds that have been studied around Kerr and Kerr-Newman black holes; thus they are dubbed acoustic clouds. We make the comparison between scalar clouds around Kerr black holes and acoustic clouds around the draining bathtub explicit by studying also the properties of scalar clouds around Kerr black holes enclosed in a cavity. Acoustic clouds suggest the possibility of testing, experimentally, the existence and properties of black hole clouds, using analog models.

  8. Can Cloud Computing Address the Scientific Computing Requirements...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for meeting the ever-increasing computational needs of scientists, Department of Energy researchers have issued a report stating that the cloud computing model is useful, but...

  9. Evaluation of Cloud-resolving and Limited Area Model Intercomparison Simulations using TWP-ICE Observations. Part 1: Deep Convective Updraft Properties

    SciTech Connect (OSTI)

    Varble, A. C.; Zipser, Edward J.; Fridlind, Ann; Zhu, Ping; Ackerman, Andrew; Chaboureau, Jean-Pierre; Collis, Scott M.; Fan, Jiwen; Hill, Adrian; Shipway, Ben

    2014-12-27T23:59:59.000Z

    Ten 3D cloud-resolving model (CRM) simulations and four 3D limited area model (LAM) simulations of an intense mesoscale convective system observed on January 23-24, 2006 during the Tropical Warm Pool – International Cloud Experiment (TWP-ICE) are compared with each other and with observed radar reflectivity fields and dual-Doppler retrievals of vertical wind speeds in an attempt to explain published results showing a high bias in simulated convective radar reflectivity aloft. This high bias results from ice water content being large, which is a product of large, strong convective updrafts, although hydrometeor size distribution assumptions modulate the size of this bias. Snow reflectivity can exceed 40 dBZ in a two-moment scheme when a constant bulk density of 100 kg m-3 is used. Making snow mass more realistically proportional to area rather than volume should somewhat alleviate this problem. Graupel, unlike snow, produces high biased reflectivity in all simulations. This is associated with large amounts of liquid water above the freezing level in updraft cores. Peak vertical velocities in deep convective updrafts are greater than dual-Doppler retrieved values, especially in the upper troposphere. Freezing of large rainwater contents lofted above the freezing level in simulated updraft cores greatly contributes to these excessive upper tropospheric vertical velocities. Strong simulated updraft cores are nearly undiluted, with some showing supercell characteristics. Decreasing horizontal grid spacing from 900 meters to 100 meters weakens strong updrafts, but not enough to match observational retrievals. Therefore, overly intense simulated updrafts may partly be a product of interactions between convective dynamics, parameterized microphysics, and large-scale environmental biases that promote different convective modes and strengths than observed.

  10. Threshold effects on renormalization group running of neutrino parameters in the low-scale seesaw model

    E-Print Network [OSTI]

    Johannes Bergstrom; Tommy Ohlsson; He Zhang

    2011-04-04T23:59:59.000Z

    We show that, in the low-scale type-I seesaw model, renormalization group running of neutrino parameters may lead to significant modifications of the leptonic mixing angles in view of so-called seesaw threshold effects. Especially, we derive analytical formulas for radiative corrections to neutrino parameters in crossing the different seesaw thresholds, and show that there may exist enhancement factors efficiently boosting the renormalization group running of the leptonic mixing angles. We find that, as a result of the seesaw threshold corrections to the leptonic mixing angles, various flavor symmetric mixing patterns (e.g., bi-maximal and tri-bimaximal mixing patterns) can be easily accommodated at relatively low energy scales, which is well within the reach of running and forthcoming experiments (e.g., the LHC).

  11. Uranus at equinox: Cloud morphology and dynamics

    E-Print Network [OSTI]

    Sromovsky, Lawrence; Hammel, Heidi; Ahue, William; de Pater, Imke; Rages, Kathy; Showalter, Mark; van Dam, Marcos

    2015-01-01T23:59:59.000Z

    As the 7 December 2007 equinox of Uranus approached, ring and atmosphere observers produced a substantial collection of observations using the 10-m Keck telescope and the Hubble Space Telescope. Those spanning the period from 7 June 2007 through 9 September 2007 we used to identify and track cloud features, determine atmospheric motions, characterize cloud morphology and dynamics, and define changes in atmospheric band structure. We confirmed the existence of the suspected northern hemisphere prograde jet, locating its peak near 58 N, and extended wind speed measurements to 73 N. For 28 cloud features we obtained extremely high wind-speed accuracy through extended tracking times. The new results confirm a small N-S asymmetry in the zonal wind profile, and the lack of any change in the southern hemisphere between 1986 (near solstice) and 2007 (near equinox) suggests that the asymmetry may be permanent rather than seasonally reversing. In the 2007 images we found two prominent groups of discrete cloud features ...

  12. Investigating plasma motion of magnetic clouds at 1 AU through a velocity-modified cylindrical force-free flux rope model

    E-Print Network [OSTI]

    Wang, Yuming; Shen, Chenglong; Liu, Rui; Wang, S

    2015-01-01T23:59:59.000Z

    Magnetic clouds (MCs) are the interplanetary counterparts of coronal mass ejections (CMEs), and usually modeled by a flux rope. By assuming the quasi-steady evolution and self-similar expansion, we introduce three types of global motion into a cylindrical force-free flux rope model, and developed a new velocity-modified model for MCs. The three types of the global motion are the linear propagating motion away from the Sun, the expanding and the poloidal motion with respect to the axis of the MC. The model is applied to 72 MCs observed by Wind spacecraft to investigate the properties of the plasma motion of MCs. First, we find that some MCs had a significant propagation velocity perpendicular to the radial direction, suggesting the direct evidence of the CME's deflected propagation and/or rotation in interplanetary space. Second, we confirm the previous results that the expansion speed is correlated with the radial propagation speed and most MCs did not expand self-similarly at 1 AU. In our statistics, about 6...

  13. Magnetic Fields in Molecular Cloud Cores

    E-Print Network [OSTI]

    Shantanu Basu

    2004-10-22T23:59:59.000Z

    Observations of magnetic field strengths imply that molecular cloud fragments are individually close to being in a magnetically critical state, even though both magnetic field and column density measurements range over two orders of magnitude. The turbulent pressure also approximately balances the self-gravitational pressure. These results together mean that the one-dimensional velocity dispersion $\\sigv$ is proportional to the mean \\Alf speed of a cloud $\\va$. Global models of MHD turbulence in a molecular cloud show that this correlation is naturally satisfied for a range of different driving strengths of the turbulence. For example, an increase of turbulent driving causes a cloud expansion which also increases $\\va$. Clouds are in a time averaged balance but exhibit large oscillatory motions, particularly in their outer rarefied regions. We also discuss models of gravitational fragmentation in a sheet-like region in which turbulence has already dissipated, including the effects of magnetic fields and ion-neutral friction. Clouds with near-critical mass-to-flux ratios lead to subsonic infall within cores, consistent with some recent observations of motions in starless cores. Conversely, significantly supercritical clouds are expected to produce extended supersonic infall.

  14. Working inside the Cloud: Developing a Cloud Computing Infrastructure

    E-Print Network [OSTI]

    Krause, Rolf

    UROP 2012 Working inside the Cloud: Developing a Cloud Computing Infrastructure Cloud computing and live-migration of running VM. USI participates to the development of the first European Cloud computing for a motivated student that will have a chance to improve his/her knowledge on Cloud computing, Java and/or Ruby

  15. Retrieval of Cloud Phase Using the Moderate Resolution Imaging Spectroradiometer Data during the Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Spangenberg, D.; Minnis, P.; Shupe, M.; Uttal, T.; Poellot, M.

    2005-03-18T23:59:59.000Z

    Improving climate model predictions over Earth's polar regions requires a comprehensive knowledge of polar cloud microphysics. Over the Arctic, there is minimal contrast between the clouds and background snow surface, making it difficult to detect clouds and retrieve their phase from space. Snow and ice cover, temperature inversions, and the predominance of mixed-phase clouds make it even more difficult to determine cloud phase. Also, since determining cloud phase is the first step toward analyzing cloud optical depth, particle size, and water content, it is vital that the phase be correct in order to obtain accurate microphysical and bulk properties. Changes in these cloud properties will, in turn, affect the Arctic climate since clouds are expected to play a critical role in the sea ice albedo feedback. In this paper, the IR trispectral technique (IRTST) is used as a starting point for a WV and 11-{micro}m brightness temperature (T11) parameterization (WVT11P) of cloud phase using MODIS data. In addition to its ability to detect mixed-phase clouds, the WVT11P also has the capability to identify thin cirrus clouds overlying mixed or liquid phase clouds (multiphase ice). Results from the Atmospheric Radiation Measurement (ARM) MODIS phase model (AMPHM) are compared to the surface-based cloud phase retrievals over the ARM North Slope of Alaska (NSA) Barrow site and to in-situ data taken from University of North Dakota Citation (CIT) aircraft which flew during the Mixed-Phase Arctic Cloud Experiment (MPACE). It will be shown that the IRTST and WVT11P combined to form the AMPHM can achieve a relative high accuracy of phase discrimination compared to the surface-based retrievals. Since it only uses MODIS WV and IR channels, the AMPHM is robust in the sense that it can be applied to daytime, twilight, and nighttime scenes with no discontinuities in the output phase.

  16. Evaluation of tropical cloud and precipitation statistics of CAM3 using CloudSat and CALIPSO data

    SciTech Connect (OSTI)

    Zhang, Y; Klein, S; Boyle, J; Mace, G G

    2008-11-20T23:59:59.000Z

    The combined CloudSat and CALIPSO satellite observations provide the first simultaneous measurements of cloud and precipitation vertical structure, and are used to examine the representation of tropical clouds and precipitation in the Community Atmosphere Model Version 3 (CAM3). A simulator package utilizing a model-to-satellite approach facilitates comparison of model simulations to observations, and a revised clustering method is used to sort the subgrid-scale patterns of clouds and precipitation into principal cloud regimes. Results from weather forecasts performed with CAM3 suggest that the model underestimates the horizontal extent of low and mid-level clouds in subsidence regions, but overestimates that of high clouds in ascending regions. CAM3 strongly overestimates the frequency of occurrence of the deep convection with heavy precipitation regime, but underestimates the horizontal extent of clouds and precipitation at low and middle levels when this regime occurs. This suggests that the model overestimates convective precipitation and underestimates stratiform precipitation consistent with a previous study that used only precipitation observations. Tropical cloud regimes are also evaluated in a different version of the model, CAM3.5, which uses a highly entraining plume in the parameterization of deep convection. While the frequency of occurrence of the deep convection with heavy precipitation regime from CAM3.5 forecasts decreases, the incidence of the low clouds with precipitation and congestus regimes increases. As a result, the parameterization change does not reduce the frequency of precipitating convection that is far too high relative to observations. For both versions of CAM, clouds and precipitation are overly reflective at the frequency of the CloudSat radar and thin clouds that could be detected by the lidar only are underestimated.

  17. Dynamic Cloud Resource Reservation via Cloud Brokerage

    E-Print Network [OSTI]

    Li, Baochun

    Department of Electrical and Computer Engineering, University of Toronto Department of Electrical@eecg.toronto.edu, liang@utoronto.ca Abstract--Infrastructure-as-a-Service clouds offer diverse pric- ing options

  18. Few-group delayed neutron model based on a consistent set of decay constants

    SciTech Connect (OSTI)

    Campbell, J.M.; Spriggs, G.D. [Los Alamos National Lab., NM (United States)

    1998-09-01T23:59:59.000Z

    During the past 50 yr, more than 200 individual sets of delayed neutron parameters have been measured for 20 different fissionable isotopes. As readily observed from these experimental results, the abundances and the decay constants for each group can vary significantly from isotope to isotope as well as varying as a function of the incident neutron energy. From a reactor dynamic standpoint, variations in the decay constants lead to additional complexity when trying to predict the dynamic behavior of reactor systems that contain two or more fissioning isotopes. For example, the six-group point-reactor model must be expanded to include six differential equations describing the precursors produced by each fissioning isotope. Hence, for a system containing five fissioning isotopes, 30 differential equations would be required to describe the total delayed neutron activity. The objective of this paper is to present a status report of the first phase of an international effort to develop a new set of delayed neutron parameters that are based on a-consistent set of decay constants that simplifies the delayed neutron model in reactor dynamic calculations.

  19. An Autonomous Reliabilit Cloud Comput

    E-Print Network [OSTI]

    Buyya, Rajkumar

    An Autonomous Reliabilit Ami Cloud Comput Department of Computing and Informa Abstract--Cloud computing paradigm allo based access to computing and storages s Internet. Since with advances of Cloud. Keywords- Cloud computing; SLA negotiat I. INTRODUCTION Cloud computing has transferred the services

  20. A THREE-DIMENSIONAL MODELING STUDY OF THE EFFECTS OF SOLID-PHASE HYDROMETEOR-CHEMICAL INTERACTIONS IN CUMULONIMBUS CLOUDS ON TROPOSPHERIC CHEMICAL DISTRIBUTIONS

    E-Print Network [OSTI]

    Stuart, Amy L.

    - and mixed-phase hydrometeors (cloud ice, snow, graupel, and hail) are often excluded or limited due of interactions of ice-phase cloud hydrometeors with volatile chemicals have found that they may significantly. 2. ICE- AND MIXED-PHASE CHEMISTRY 2.1 Gas-Solid Transfer Gas-phase chemical species can diffuse

  1. A Test of the Simulation of Tropical Convective Cloudiness by a Cloud-Resolving Model MARIO A. LOPEZ, DENNIS L. HARTMANN, PETER N. BLOSSEY, ROBERT WOOD,

    E-Print Network [OSTI]

    Hartmann, Dennis

    effects are investigated. The simulation of anvil cloud can be improved while maintaining a good and water vapor have a strong influence on the radiation budget of the earth, and it is unclear how cloud solar radiation, although their effect on the net energy balance is often much less than

  2. 1EMC CONFIDENTIAL--INTERNAL USE ONLY Cloud based Personal Information Management

    E-Print Network [OSTI]

    1EMC CONFIDENTIAL--INTERNAL USE ONLY Cloud based Personal Information Management ­ Introduction to EMC Cloud Computing Jidong Chen Sr. Research Scientist Information Management Group EMC Research China Dec., 2008 #12;2EMC CONFIDENTIAL--INTERNAL USE ONLY Agenda Introduction to Personal Information Cloud

  3. Clouds up close | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    interactions that affect clouds and thus improve climate projections. Contact Heng Xiao Pacific Northwest National Laboratory 902 Battelle Blvd., PO Box 999 MSIN: K9-30...

  4. Finance Idol Word Cloud

    Broader source: Energy.gov [DOE]

    This word cloud represents the topics discussed during the Big and Small Ideas: How to Lower Solar Financing Costs breakout session at the SunShot Grand Challenge.

  5. Isolating signatures of major cloud-cloud collisions using position-velocity diagrams

    E-Print Network [OSTI]

    Haworth, T J; Fukui, Y; Torii, K; Dale, J E; Shima, K; Takahira, K; Habe, A; Hasegawa, K

    2015-01-01T23:59:59.000Z

    Collisions between giant molecular clouds are a potential mechanism for triggering the formation of massive stars, or even super star clusters. The trouble is identifying this process observationally and distinguishing it from other mechanisms. We produce synthetic position-velocity diagrams from models of: cloud-cloud collisions, non-interacting clouds along the line of sight, clouds with internal radiative feedback and a more complex cloud evolving in a galactic disc, to try and identify unique signatures of collision. We find that a broad bridge feature connecting two intensity peaks, spatially correlated but separated in velocity, is a signature of a high velocity cloud-cloud collision. We show that the broad bridge feature is resilient to the effects of radiative feedback, at least to around 2.5Myr after the formation of the first massive (ionising) star. However for a head on 10km/s collision we find that this will only be observable from 20-30 per cent of viewing angles. Such broad-bridge features have...

  6. Existence of new nonlocal field theory on noncommutative space and spiral flow in renormalization group analysis of matrix models

    E-Print Network [OSTI]

    Kawamoto, Shoichi

    2015-01-01T23:59:59.000Z

    In the previous study, we formulate a matrix model renormalization group based on the fuzzy spherical harmonics with which a notion of high/low energy can be attributed to matrix elements, and show that it exhibits locality and various similarity to the usual Wilsonian renormalization group of quantum field theory. In this work, we continue the renormalization group analysis of a matrix model with emphasis on nonlocal interactions where the fields on antipodal points are coupled. They are indeed generated in the renormalization group procedure and are tightly related to the noncommutative nature of the geometry. We aim at formulating renormalization group equations including such nonlocal interactions and finding existence of nontrivial field theory with antipodal interactions on the fuzzy sphere. We find several nontrivial fixed points and calculate the scaling dimensions associated with them. We also consider the noncommutative plane limit and then no consistent fixed point is found. This contrast between t...

  7. Sandia Energy - Cloud Computing Services

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Cloud Computing Services Home Stationary Power Safety, Security & Resilience of Energy Infrastructure Grid Modernization Cyber Security for Electric Infrastructure Cloud Computing...

  8. Compact, Isolated High-Velocity Clouds

    E-Print Network [OSTI]

    W. B. Burton; R. Braun; V. de Heij

    2002-06-20T23:59:59.000Z

    We consider here the class of compact, isolated, high-velocity HI clouds, CHVCs, which are sharply bounded in angular extent down to a limiting column density of 1.5x10^18 cm^-2. We describe our automated search algorithm and it's application to the LDS north of dec= -28 deg. and the HIPASS data south of dec=0, resulting in an all--sky catalog numbering 246 CHVCs. We argue that these objects are more likely to represent a single phenomenon in a similar evolutionary state than would a sample which included any of the major HVC complexes. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densities, (4) the number distribution of angular sizes, and (5) the number distribution of line widths. We show that the spatial and kinematic deployments of the ensemble of CHVCs contain various clues regarding their characteristic distance. These clues are not compatible with a location of the ensemble within the Galaxy proper. The deployments resemble in several regards those of the Local Group galaxies. We describe a model testing the hypothesis that the CHVCs are a Local Group population. The agreement of the model with the data is judged by extracting the observables from simulations, in a manner consistent with the sensitivities of the observations and explicitly taking account of Galactic obscuration. We show that models in which the CHVCs are the HI counterparts of dark-matter halos evolving in the Local Group potential provide a good match to the observables, if account is taken of tidal and ram--pressure disruption, the consequences of obscuration due to Galactic HI and of differing sensitivities and selection effects pertaining to the surveys.

  9. Parameterizing Size Distribution in Ice Clouds

    SciTech Connect (OSTI)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25T23:59:59.000Z

    PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 µm) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 µm), known as the “small mode”. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice cloud optical properties formulated in terms of PSD parameters in combination with remote measurements of thermal radiances to characterize the small mode. This is possible since the absorption efficiency (Qabs) of small mode crystals is larger at 12 µm wavelength relative to 11 µm wavelength due to the process of wave resonance or photon tunneling more active at 12 µm. This makes the 12/11 µm absorption optical depth ratio (or equivalently the 12/11 µm Qabs ratio) a means for detecting the relative concentration of small ice particles in cirrus. Using this principle, this project tested and developed PSD schemes that can help characterize cirrus clouds at each of the three ARM sites: SGP, NSA and TWP. This was the main effort of this project. These PSD schemes and ice sedimentation velocities predicted from them have been used to test the new cirrus microphysics parameterization in the GCM known as the Community Climate Systems Model (CCSM) as part of an ongoing collaboration with NCAR. Regarding the second problem, we developed and did preliminary testing on a passive thermal method for retrieving the total water path (TWP) of Arctic mixed phase clouds where TWPs are often in the range of 20 to 130 g m-2 (difficult for microwave radiometers to accurately measure). We also developed a new radar method for retrieving the cloud ice water content (IWC), which can be vertically integrated to yield the ice water path (IWP). These techniques were combined to determine the IWP and liquid water path (LWP) in Arctic clouds, and hence the fraction of ice and liquid water. We have tested this approach using a case study from the ARM field campaign called M-PACE (Mixed-Phase Arctic Cloud Experiment). This research led to a new satellite remote sensing method that appears promising for detecting low levels of liquid water in high clouds typically between -20 and -36 oC. We hope to develop this method in future research.

  10. CONTRIBUTED Green Cloud Computing

    E-Print Network [OSTI]

    Tucker, Rod

    to manage energy consumption across the entire information and communications technology (ICT) sector. While considers both public and private clouds, and includes energy consumption in switching and transmission to energy consumption and cloud computing seems to be an alternative to office-based computing. By Jayant

  11. Toward Securing Sensor Clouds

    E-Print Network [OSTI]

    · 32 GB microSDHC storage 2 Image from http://hothardware.com/News/Leaked-Motorola-DROID-X-2-Daytona Computer Mini Computer External Storage External Storage Router Router Router Router Cloud Computing Cloud: micro surveys, amber alerts 4 #12;Router Router Router Router Mini Computer Mini Computer Mini Computer

  12. arctic mixed-phase clouds: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    low-level Arctic clouds in cold seasons and have a significant impact on the surface energy budget. However, the treatment of mixed-phase clouds in most current climate models...

  13. On the Feasibility of Precisely Measuring the Properties of a Precipitating Cloud with a Weather Radar

    E-Print Network [OSTI]

    Runnels, R.C.

    In this paper the results of an investigation are presented that are concerned with the feasibility of employing a weather radar to make precise measurements of the properties of a precipitating cloud. A schematic cloud is proposed as a model...

  14. Near-Global Survey of Effective Droplet Radii in Liquid Water Clouds Using ISCCP Data 1 . Introduction

    E-Print Network [OSTI]

    Han, Quingyuan

    VOLUME 7 Near-Global Survey of Effective Droplet Radii in Liquid Water Clouds Using ISCCP Data 1 indicate the magnitude ofaerosol effects on clouds. A method, based on a complete radiative transfer model the radiative effects ofwater vapor and clouds and the hydrological cycle, and create several important cloud

  15. July 2012July 2012 Cloud Computing and Virtualization:Cloud Computing and Virtualization

    E-Print Network [OSTI]

    Liu, Jiangchuan (JC)

    July 2012July 2012 Cloud Computing and Virtualization:Cloud Computing and Virtualization/26/2633 Recent: CloudRecent: Cloud The fast growth of cloud computing Cloud file storage/synchronization services Google entries about cloud computing: 184,000,000 #12;July 2012July 2012 44/26/2644 Our CloudOur Cloud 7

  16. Investigation of Thin Cirrus Cloud Optical and Microphysical Properties on the Basis of Satellite Observations and Fast Radiative Transfer Models 

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

    observations and fast radiative transfer models (RTMs). In the first part, we develop two computationally efficient RTMs simulating satellite observations under cloudy-sky conditions in the visible/shortwave infrared (VIS/SWIR) and thermal inferred (IR...

  17. AEROSOL, CLOUDS, AND CLIMATE CHANGE

    SciTech Connect (OSTI)

    SCHWARTZ, S.E.

    2005-09-01T23:59:59.000Z

    Earth's climate is thought to be quite sensitive to changes in radiative fluxes that are quite small in absolute magnitude, a few watts per square meter, and in relation to these fluxes in the natural climate. Atmospheric aerosol particles exert influence on climate directly, by scattering and absorbing radiation, and indirectly by modifying the microphysical properties of clouds and in turn their radiative effects and hydrology. The forcing of climate change by these indirect effects is thought to be quite substantial relative to forcing by incremental concentrations of greenhouse gases, but highly uncertain. Quantification of aerosol indirect forcing by satellite- or ground-based remote sensing has proved quite difficult in view of inherent large variation in the pertinent observables such as cloud optical depth, which is controlled mainly by liquid water path and only secondarily by aerosols. Limited work has shown instances of large magnitude of aerosol indirect forcing, with local instantaneous forcing upwards of 50 W m{sup 66}-2. Ultimately it will be necessary to represent aerosol indirect effects in climate models to accurately identify the anthropogenic forcing at present and over secular time and to assess the influence of this forcing in the context of other forcings of climate change. While the elements of aerosol processes that must be represented in models describing the evolution and properties of aerosol particles that serve as cloud condensation particles are known, many important components of these processes remain to be understood and to be represented in models, and the models evaluated against observation, before such model-based representations can confidently be used to represent aerosol indirect effects in climate models.

  18. When Clouds become Green: the Green Open Cloud Architecture

    E-Print Network [OSTI]

    Boyer, Edmond

    of a new original energy-efficient Cloud infrastructure called Green Open Cloud. Keywords. Energy with the support of energy-efficient frameworks dedicated to Cloud architectures. Virtualization is a key feature of the energy-aware Cloud infras- tructure that we propose. The conclusion and future works are reviewed

  19. Do Gamma-Ray Bursts Come from the Oort Cloud?

    E-Print Network [OSTI]

    T. E. Clarke; O. Blaes; adn S. Tremaine

    1993-10-02T23:59:59.000Z

    We examine the possibility that gamma-ray bursts arise from sources in the Oort comet cloud, basing most of our arguments on accepted models for the formation and spatial distribution of the cloud. We identify three severe problems with such models: (1) There is no known mechanism for producing bursts that can explain the observed burst rate and energetics without violating other observational constraints. (2) The bright source counts cannot be reconciled with standard models for the phase-space distribution of objects in the Oort cloud. (3) The observed isotropy of the available burst data is inconsistent with the expected angular distribution of sources in the Oort cloud. We therefore assert that Oort cloud models of gamma-ray bursts are extremely implausible.

  20. Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud

    E-Print Network [OSTI]

    T. Kudoh; S. Basu

    2003-06-23T23:59:59.000Z

    We perform numerical simulations of nonlinear MHD waves in a gravitationally stratified molecular cloud that is bounded by a hot and tenuous external medium. We study the relation between the strength of the turbulence and various global properties of a molecular cloud, within a 1.5-dimensional approximation. Under the influence of a driving source of Alfvenic disturbances, the cloud is lifted up by the pressure of MHD waves and reaches a steady-state characterized by oscillations about a new time-averaged equilibrium state. The nonlinear effect results in the generation of longitudinal motions and many shock waves; however, the wave kinetic energy remains predominantly in transverse, rather than longitudinal, motions. There is an approximate equipartition of energy between the transverse velocity and fluctuating magnetic field (aspredicted by small-amplitude theory) in the region of the stratified cloud which contains most of the mass; however, this relation breaks down in the outer regions, particularly near the cloud surface, where the motions have a standing-wave character. This means that the Chandrasekhar-Fermi formula applied to molecular clouds must be significantly modified in such regions. Models of an ensemble of clouds show that, for various strengths of the input energy, the velocity dispersion in the cloud $\\sigma \\propto Z^{0.5}$, where $Z$ is a characteristic size of the cloud.Furthermore, $\\sigma$ is always comparable to the mean Alfven velocity of the cloud, consistent with observational results.

  1. NEGLECTED CLOUDS IN T AND Y DWARF ATMOSPHERES

    SciTech Connect (OSTI)

    Morley, Caroline V.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Marley, Mark S. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Visscher, Channon [Southwest Research Institute, Boulder, CO 80302 (United States); Saumon, Didier [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Leggett, S. K., E-mail: cmorley@ucolick.org [Gemini Observatory, Northern Operations Center, Hilo, HI 96720 (United States)

    2012-09-10T23:59:59.000Z

    As brown dwarfs cool, a variety of species condense in their atmospheres, forming clouds. Iron and silicate clouds shape the emergent spectra of L dwarfs, but these clouds dissipate at the L/T transition. A variety of other condensates are expected to form in cooler T dwarf atmospheres. These include Cr, MnS, Na{sub 2}S, ZnS, and KCl, but the opacity of these optically thinner clouds has not been included in previous atmosphere models. Here, we examine their effect on model T and Y dwarf atmospheres. The cloud structures and opacities are calculated using the Ackerman and Marley cloud model, which is coupled to an atmosphere model to produce atmospheric pressure-temperature profiles in radiative-convective equilibrium. We generate a suite of models between T{sub eff} = 400 and 1300 K, log g = 4.0 and 5.5, and condensate sedimentation efficiencies from f{sub sed} = 2 to 5. Model spectra are compared to two red T dwarfs, Ross 458C and UGPS 0722-05; models that include clouds are found to match observed spectra significantly better than cloudless models. The emergence of sulfide clouds in cool atmospheres, particularly Na{sub 2}S, may be a more natural explanation for the 'cloudy' spectra of these objects, rather than the reemergence of silicate clouds that wane at the L-to-T transition. We find that sulfide clouds provide a mechanism to match the near- and mid-infrared colors of observed T dwarfs. Our results indicate that including the opacity of condensates in T dwarf atmospheres is necessary to accurately determine the physical characteristics of many of the observed objects.

  2. Convective Cloud Lifecycles Lunchtime seminar

    E-Print Network [OSTI]

    Plant, Robert

    Convective Cloud Lifecycles Lunchtime seminar 19th May 2009 Bob Plant Department of Meteorology, University of Reading, UK #12;Introduction Obtain life cycle statistics for clouds in CRM simulations Why Conclusions Convective Cloud Lifecycles ­ p.1/3 #12;Why bother? Convective Cloud Lifecycles ­ p.2/3 #12;Some

  3. Accretion onto a black hole in a string cloud background

    E-Print Network [OSTI]

    Apratim Ganguly; Sushant G. Ghosh; Sunil D. Maharaj

    2014-09-28T23:59:59.000Z

    We examine the accretion process onto the black hole with a string cloud background, where the horizon of the black hole has an enlarged radius $r_H=2 M/(1-\\alpha)$, due to the string cloud parameter $\\alpha\\; (0 \\leq \\alpha cloud parameter $\\alpha$. We also find the gas compression ratios and temperature profiles below the accretion radius and at the event horizon. It is shown that the mass accretion rate, for both the relativistic and the non-relativistic fluid by a black hole in the string cloud model, increases with increase in $\\alpha$.

  4. Collider Detector at Fermilab (CDF): Data from Standard Model and Supersymmetric Higgs Bosons Research of the Higgs Group

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Collider Detector at Fermilab (CDF) is a Tevatron experiment at Fermilab. The Tevatron, a powerful particle accelerator, accelerates protons and antiprotons close to the speed of light, and then makes them collide head-on inside the CDF detector. The CDF detector is used to study the products of such collisions. The CDF Physics Group at Fermilab is organized into six working groups, each with a specific focus. The Higgs group searches for Standard Model and Supersymmetric Higgs bosons. Their public web page makes data and numerous figures available from both CDF Runs I and II.

  5. High-velocity clouds: a diverse phenomenon

    E-Print Network [OSTI]

    B. P. Wakker

    2001-09-13T23:59:59.000Z

    In this contribution the current state of knowledge about the high-velocity clouds (HVCs) is summarized. Recent progress has shown that the HVCs are a diverse phenomenon. The intermediate-velocity clouds (IVCs) are likely to be part of a Galactic Fountain. The Magellanic Stream is a tidal remnant. HVC complex C (possibly complexes A and GCN) are low-metallicity clouds near the Galaxy; they could be remnants of the formation of the Galaxy or old tidal streams extracted from nearby dwarf galaxies. Having a substantial number of HI HVCs dispersed throughout the Local Group seems incompatible with the observed HI mass function of galaxies. Finally, FUSE finds high-velocity OVI, some of which is clearly associated with HI HVCs, but some which is not.

  6. Interannual Variations of Arctic Cloud Types

    E-Print Network [OSTI]

    Hochberg, Michael

    Sciences #12;Changes in Arctic Climate What is the role of cloud cover in Arctic climate change? What is the Cloud Radiative Effect (CRE) in the Arctic? #12;CRE depends on season, cloud type CRE ­ whether clouds specifically chosen to include nighttime obs Total cloud cover and nine cloud types: - High cloud (cirriform

  7. Interannual Variations of Arctic Cloud Types

    E-Print Network [OSTI]

    Hochberg, Michael

    Declining September sea-ice extent #12;Clouds & Changes in Arctic Climate What is the role of cloud cover in Arctic climate change? What is the Cloud Radiative Effect (CRE) in the Arctic? #12;CRE Defined CRE nighttime obs Total cloud cover and nine cloud types: - High cloud (cirriform) - Middle Clouds: Altocumulus

  8. Polytropes: Implications for Molecular Clouds and Dark Matter

    E-Print Network [OSTI]

    Christopher F. McKee

    2000-08-02T23:59:59.000Z

    Polytropic models are reasonably successful in acounting for the observed features of molecular clouds. Multi-pressure polytropes include the various pressure components that are important in molecular clouds, whereas composite polytropes provide a representation for the core halo structure. Small, very dense (n~10^{11} cm^{-3}) molecular clouds have been proposed as models for both dark matter and for extreme scattering events. Insofar as the equation of state in these clouds can be represented by a single polytropic relation (pressure varies as a power of the density), such models conflict with observation. It is possible to contrive composite polytropes that do not conflict with observation, but whether the thermal properties of the clouds are consistent with such structure remains to be determined.

  9. Sharing-based Privacy and Availability of Cloud Data Warehouses

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    model in the cloud. 1 Introduction Business intelligence (BI) and data analytics have been an ever earlier been too costly to process in time, money or human resources can be analyzed efficiently.harbi@univ-lyon2.fr jerome.darmont@univ-lyon2.fr Abstract. Cloud computing can help reduce costs, increase business

  10. First observations of tracking clouds using scanning ARM cloud radars

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Borque, Paloma; Giangrande, Scott; Kollias, Pavlos

    2014-12-01T23:59:59.000Z

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud fieldmore »and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.« less

  11. First observations of tracking clouds using scanning ARM cloud radars

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Borque, Paloma [McGill Univ., Montreal, QC (Canada); Giangrande, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Kollias, Pavlos [McGill Univ., Montreal, QC (Canada)

    2014-12-01T23:59:59.000Z

    Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large drop formation (‘‘first echo’’). These measurements complement cloud and precipitation tracking using geostationary satellites and weather radars. Here, two-dimensional (2-D) Along-Wind Range Height Indicator (AW-RHI) observations of a population of shallow cumuli (with and without precipitation) from the 35-GHz scanning ARM cloud radar (SACR) at the DOE Atmospheric Radiation Measurements (ARM) program Southern Great Plains (SGP) site are presented. Observations from the ARM SGP network of scanning precipitation radars are used to provide the larger scale context of the cloud field and to highlight the advantages of the SACR to detect the numerous, small, non-precipitating cloud elements. A new Cloud Identification and Tracking Algorithm (CITA) is developed to track cloud elements. In CITA, a cloud element is identified as a region having a contiguous set of pixels exceeding a preset reflectivity and size threshold. The high temporal resolution of the SACR 2-D observations (30 sec) allows for an area superposition criteria algorithm to match cloud elements at consecutive times. Following CITA, the temporal evolution of cloud element properties (number, size, and maximum reflectivity) is presented. The vast majority of the designated elements during this cumulus event were short-lived non-precipitating clouds having an apparent life cycle shorter than 15 minutes. The advantages and disadvantages of cloud tracking using an SACR are discussed.

  12. Migrating enterprise storage applications to the cloud

    E-Print Network [OSTI]

    Vrable, Michael Daniel

    2011-01-01T23:59:59.000Z

    2.1 Cloud Providers . . . . . . . . . . . .2.1.1 Cloud Storage . . . . . . . . .2.1.2 Cloud Computation . . . . . . 2.2 Enterprise Storage

  13. A developer's survey on different cloud platforms

    E-Print Network [OSTI]

    Doan, Dzung

    2009-01-01T23:59:59.000Z

    1 Introduction Cloud computing is a computing paradigm inFor this reason, cloud computing has also been describedparallel processing. Cloud computing can be contrasted with

  14. Cloud cover increase with increasing aerosol absorptivity: A counterexample to the conventional semidirect aerosol effect

    E-Print Network [OSTI]

    humidity. The net effect is more low cloud cover with increasing aerosol absorption. The higher specific by dust radiative heating. Although in some areas our model exhibits a reduction of low cloud cover due are expected to have a similar effect. Citation: Perlwitz, J., and R. L. Miller (2010), Cloud cover increase

  15. INTERANNUAL AND SEASONAL VARIATIONS IN MARINE BOUNDARY LAYER CLOUD FRACTION AND LOWER

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    : ___________________________________________________________ #12;i Abstract Marine boundary layer (MBL) clouds have a large effect on the global radiation budget cooling effect in the MBL. Thus, simulating MBL clouds in General Circulation Models (GCM) is crucialINTERANNUAL AND SEASONAL VARIATIONS IN MARINE BOUNDARY LAYER CLOUD FRACTION AND LOWER TROPOSPHERIC

  16. Interpretation of neutrino-matter interactions at low energies as contraction of gauge group of Electroweak Model

    SciTech Connect (OSTI)

    Gromov, N. A., E-mail: gromov@dm.komisc.ru [Komi Science Center UrD RAS, Department of Mahematics (Russian Federation)

    2013-09-15T23:59:59.000Z

    The very weak neutrino-matter interactions are explained with the help of the gauge group contraction of the standard Electroweak Model. The mathematical contraction procedure is connected with the energy dependence of the interaction cross section for neutrinos and corresponds to the limiting case of the Electroweak Model at low energies. Contraction parameter is connected with the universal Fermi constant of weak interactions and neutrino energy as j{sup 2}(s) = {radical}(G{sub F} s)

  17. Les Houches Physics at TeV Colliders 2005 Beyond the Standard Model Working Group: Summary Report

    SciTech Connect (OSTI)

    Allanach, B.C.; /Cambridge U., DAMTP; Grojean, C.; /Saclay, SPhT /CERN; Skands, P.; /Fermilab; Accomando, E.; Azuelos, G.; Baer, H.; Balazs, C.; Belanger, G.; Benakli, K.; Boudjema, F.; Brelier, B.; Bunichev, V.; Cacciapaglia, G.; Carena, M.; Choudhury, D.; Delsart, P.-A.; De Sanctis, U.; Desch, K.; Dobrescu, B.A.; Dudko, L.; El Kacimi, M.; /Saclay,

    2006-03-17T23:59:59.000Z

    The work contained herein constitutes a report of the ''Beyond the Standard Model'' working group for the Workshop ''Physics at TeV Colliders'', Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

  18. ARM - Midlatitude Continental Convective Clouds

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Jensen, Mike; Bartholomew, Mary Jane; Genio, Anthony Del; Giangrande, Scott; Kollias, Pavlos

    Convective processes play a critical role in the Earth's energy balance through the redistribution of heat and moisture in the atmosphere and their link to the hydrological cycle. Accurate representation of convective processes in numerical models is vital towards improving current and future simulations of Earths climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales important to convective processes and therefore must turn to parameterization schemes to represent these processes. In turn, parameterization schemes in cloud-resolving models need to be evaluated for their generality and application to a variety of atmospheric conditions. Data from field campaigns with appropriate forcing descriptors have been traditionally used by modelers for evaluating and improving parameterization schemes.

  19. Cloud Properties and Radiative Heating Rates for TWP

    SciTech Connect (OSTI)

    Comstock, Jennifer

    2013-11-07T23:59:59.000Z

    A cloud properties and radiative heating rates dataset is presented where cloud properties retrieved using lidar and radar observations are input into a radiative transfer model to compute radiative fluxes and heating rates at three ARM sites located in the Tropical Western Pacific (TWP) region. The cloud properties retrieval is a conditional retrieval that applies various retrieval techniques depending on the available data, that is if lidar, radar or both instruments detect cloud. This Combined Remote Sensor Retrieval Algorithm (CombRet) produces vertical profiles of liquid or ice water content (LWC or IWC), droplet effective radius (re), ice crystal generalized effective size (Dge), cloud phase, and cloud boundaries. The algorithm was compared with 3 other independent algorithms to help estimate the uncertainty in the cloud properties, fluxes, and heating rates (Comstock et al. 2013). The dataset is provided at 2 min temporal and 90 m vertical resolution. The current dataset is applied to time periods when the MMCR (Millimeter Cloud Radar) version of the ARSCL (Active Remotely-Sensed Cloud Locations) Value Added Product (VAP) is available. The MERGESONDE VAP is utilized where temperature and humidity profiles are required. Future additions to this dataset will utilize the new KAZR instrument and its associated VAPs.

  20. Cloud Properties and Radiative Heating Rates for TWP

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Comstock, Jennifer

    A cloud properties and radiative heating rates dataset is presented where cloud properties retrieved using lidar and radar observations are input into a radiative transfer model to compute radiative fluxes and heating rates at three ARM sites located in the Tropical Western Pacific (TWP) region. The cloud properties retrieval is a conditional retrieval that applies various retrieval techniques depending on the available data, that is if lidar, radar or both instruments detect cloud. This Combined Remote Sensor Retrieval Algorithm (CombRet) produces vertical profiles of liquid or ice water content (LWC or IWC), droplet effective radius (re), ice crystal generalized effective size (Dge), cloud phase, and cloud boundaries. The algorithm was compared with 3 other independent algorithms to help estimate the uncertainty in the cloud properties, fluxes, and heating rates (Comstock et al. 2013). The dataset is provided at 2 min temporal and 90 m vertical resolution. The current dataset is applied to time periods when the MMCR (Millimeter Cloud Radar) version of the ARSCL (Active Remotely-Sensed Cloud Locations) Value Added Product (VAP) is available. The MERGESONDE VAP is utilized where temperature and humidity profiles are required. Future additions to this dataset will utilize the new KAZR instrument and its associated VAPs.

  1. Modelling and Improving Group Communication in Server Operating Systems Michael Kwok, Tim Brecht, Martin Karsten, Jialin Song

    E-Print Network [OSTI]

    Li, Ming

    Modelling and Improving Group Communication in Server Operating Systems Michael Kwok, Tim Brecht implementations use a client-server archi- tecture that requires the server to send the same data to all members data from the server to each recipient in a unicast fashion. The problem with this approach

  2. Algorithm development and verification of UASCM for multi-dimension and multi-group neutron kinetics model

    SciTech Connect (OSTI)

    Si, S. [Shanghai Nuclear Engineering Research and Design Inst., No. 29 Hongcao Road, Shanghai 200233 (China)

    2012-07-01T23:59:59.000Z

    The Universal Algorithm of Stiffness Confinement Method (UASCM) for neutron kinetics model of multi-dimensional and multi-group transport equations or diffusion equations has been developed. The numerical experiments based on transport theory code MGSNM and diffusion theory code MGNEM have demonstrated that the algorithm has sufficient accuracy and stability. (authors)

  3. Thin Cloud Length Scales Using CALIPSO and CloudSat Data

    E-Print Network [OSTI]

    Solbrig, Jeremy E.

    2010-10-12T23:59:59.000Z

    Thin clouds are the most difficult cloud type to observe. The recent availability of joint cloud products from the active remote sensing instruments aboard CloudSat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) facilitates...

  4. A Coordinated Effort to Improve Parameterization of High-Latitude Cloud and Radiation Processes

    SciTech Connect (OSTI)

    J. O. Pinto, A.H. Lynch

    2005-12-14T23:59:59.000Z

    The goal of this project is the development and evaluation of improved parameterization of arctic cloud and radiation processes and implementation of the parameterizations into a climate model. Our research focuses specifically on the following issues: (1) continued development and evaluation of cloud microphysical parameterizations, focusing on issues of particular relevance for mixed phase clouds; and (2) evaluation of the mesoscale simulation of arctic cloud system life cycles.

  5. Simulations of Arctic Mixed-Phase Clouds in Forecasts with CAM3 and AM2 for M-PACE

    SciTech Connect (OSTI)

    Xie, Shaocheng; Boyle, James; Klein, Stephen A.; Liu, Xiaohong; Ghan, Steven J.

    2008-02-29T23:59:59.000Z

    Simulations of mixed-phase clouds in short-range forecasts with the National Center for Atmospheric Research Community Atmosphere Model version 3 (CAM3) and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model (AM2) for the Mixed-Phase Arctic Cloud Experiment (M-PACE) are performed under the DOE CCPP-ARM Parameterization Testbed (CAPT), which initializes the climate models with analysis data produced from numerical weather prediction (NWP) centers. It is shown that CAM3 significantly underestimates the observed boundary layer mixed-phase clouds and cannot realistically simulate the variations with temperature and cloud height of liquid water fraction in the total cloud condensate based an oversimplified cloud microphysical scheme. In contrast, AM2 reasonably reproduces the observed boundary layer clouds while its clouds contain much less cloud condensate than CAM3 and the observations. Both models underestimate the observed cloud top and base for the boundary layer clouds. The simulation of the boundary layer mixed-phase clouds and their microphysical properties is considerably improved in CAM3 when a new physically based cloud microphysical scheme is used. The new scheme also leads to an improved simulation of the surface and top of the atmosphere longwave radiative fluxes in CAM3. It is shown that the Bergeron-Findeisen process, i.e., the ice crystal growth by vapor deposition at the expense of coexisting liquid water, is important for the models to correctly simulate the characteristics of the observed microphysical properties in mixed-phase clouds. Sensitivity tests show that these results are not sensitive to the analysis data used for model initializations. Increasing model horizontal resolution helps capture the subgrid-scale features in Arctic frontal clouds but does not help improve the simulation of the single-layer boundary layer clouds. Ice crystal number density has large impact on the model simulated mixed-phase clouds and their microphysical properties and needs to be accurately represented in climate models.

  6. Tropical Warm Pool International Cloud Experiment TWP-ICE Cloud and rain characteristics in the Australian Monsoon

    SciTech Connect (OSTI)

    May, P.T., Jakob, C., and Mather, J.H.

    2004-05-31T23:59:59.000Z

    The impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them.

  7. Testing cloud microphysics parameterizations in NCAR CAM5 with ISDAC and M-PACE observations

    SciTech Connect (OSTI)

    Liu X.; Lin W.; Xie, S.; Boyle, J.; Klein, S. A.; Shi, X.; Wang, Z.; Ghan, S. J.; Earle, M.; Liu, P. S. K.; Zelenyuk, A.

    2011-12-24T23:59:59.000Z

    Arctic clouds simulated by the National Center for Atmospheric Research (NCAR) Community Atmospheric Model version 5 (CAM5) are evaluated with observations from the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Indirect and Semi-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its North Slope of Alaska site in April 2008 and October 2004, respectively. Model forecasts for the Arctic spring and fall seasons performed under the Cloud-Associated Parameterizations Testbed framework generally reproduce the spatial distributions of cloud fraction for single-layer boundary-layer mixed-phase stratocumulus and multilayer or deep frontal clouds. However, for low-level stratocumulus, the model significantly underestimates the observed cloud liquid water content in both seasons. As a result, CAM5 significantly underestimates the surface downward longwave radiative fluxes by 20-40 W m{sup -2}. Introducing a new ice nucleation parameterization slightly improves the model performance for low-level mixed-phase clouds by increasing cloud liquid water content through the reduction of the conversion rate from cloud liquid to ice by the Wegener-Bergeron-Findeisen process. The CAM5 single-column model testing shows that changing the instantaneous freezing temperature of rain to form snow from -5 C to -40 C causes a large increase in modeled cloud liquid water content through the slowing down of cloud liquid and rain-related processes (e.g., autoconversion of cloud liquid to rain). The underestimation of aerosol concentrations in CAM5 in the Arctic also plays an important role in the low bias of cloud liquid water in the single-layer mixed-phase clouds. In addition, numerical issues related to the coupling of model physics and time stepping in CAM5 are responsible for the model biases and will be explored in future studies.

  8. Ice cloud single-scattering property models with the full phase matrix at wavelengths from 0.2 to 100 mm

    E-Print Network [OSTI]

    Baum, Bryan A.

    W. Dayton Street, Madison, WI 53706, United States b Texas A&M University, College Station, TX February 2014 Available online 11 March 2014 Keywords: Ice clouds Light scattering Remote sensing Radiative agreement between solar and infrared optical thicknesses. Finally, spectral results are presented

  9. Ice Heating Up Cold Clouds | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ice Heating Up Cold Clouds Ice Heating Up Cold Clouds Released: October 04, 2011 In a heated battle, ice crystals win the competition for cloud water vapor The mighty cloud ice...

  10. Cloud Based Applications and Platforms (Presentation)

    SciTech Connect (OSTI)

    Brodt-Giles, D.

    2014-05-15T23:59:59.000Z

    Presentation to the Cloud Computing East 2014 Conference, where we are highlighting our cloud computing strategy, describing the platforms on the cloud (including Smartgrid.gov), and defining our process for implementing cloud based applications.

  11. LIDAR, Point Clouds, and their Archaeological Applications

    SciTech Connect (OSTI)

    White, Devin A [ORNL

    2013-01-01T23:59:59.000Z

    It is common in contemporary archaeological literature, in papers at archaeological conferences, and in grant proposals to see heritage professionals use the term LIDAR to refer to high spatial resolution digital elevation models and the technology used to produce them. The goal of this chapter is to break that association and introduce archaeologists to the world of point clouds, in which LIDAR is only one member of a larger family of techniques to obtain, visualize, and analyze three-dimensional measurements of archaeological features. After describing how point clouds are constructed, there is a brief discussion on the currently available software and analytical techniques designed to make sense of them.

  12. Radion clouds around evaporating black holes

    E-Print Network [OSTI]

    J. R. Morris

    2009-09-03T23:59:59.000Z

    A Kaluza-Klein model, with a matter source associated with Hawking radiation from an evaporating black hole, is used to obtain a simple form for the radion effective potential. The environmental effect generally causes a matter-induced shift of the radion vacuum, resulting in the formation of a radion cloud around the hole. There is an albedo due to the radion cloud, with an energy dependent reflection coefficient that depends upon the size of the extra dimensions and the temperature of the hole.

  13. Long-term impacts of aerosols on vertical development of cloud and precipitation

    SciTech Connect (OSTI)

    Li Z.; Liu Y.; Niu, F.; Fan, J.; Rosenfeld, D.; Ding, Y.

    2011-11-13T23:59:59.000Z

    Aerosols alter cloud density and the radiative balance of the atmosphere. This leads to changes in cloud microphysics and atmospheric stability, which can either suppress or foster the development of clouds and precipitation. The net effect is largely unknown, but depends on meteorological conditions and aerosol properties. Here, we examine the long-term impact of aerosols on the vertical development of clouds and rainfall frequencies, using a 10-year dataset of aerosol, cloud and meteorological variables collected in the Southern Great Plains in the United States. We show that cloud-top height and thickness increase with aerosol concentration measured near the ground in mixed-phase clouds-which contain both liquid water and ice-that have a warm, low base. We attribute the effect, which is most significant in summer, to an aerosol-induced invigoration of upward winds. In contrast, we find no change in cloud-top height and precipitation with aerosol concentration in clouds with no ice or cool bases. We further show that precipitation frequency and rain rate are altered by aerosols. Rain increases with aerosol concentration in deep clouds that have a high liquid-water content, but declines in clouds that have a low liquid-water content. Simulations using a cloud-resolving model confirm these observations. Our findings provide unprecedented insights of the long-term net impacts of aerosols on clouds and precipitation.

  14. Electron Cloud observation in the LHC

    E-Print Network [OSTI]

    Rumolo, G; Baglin, V; Bartosik, H; Biancacci, N; Baudrenghien, P; Bregliozzi, G; Chiggiato, P; Claudet, S; De Maria, R; Esteban-Muller, J; Favier, M; Hansen, C; Höfle, W; Jimenez, J M; Kain, V; Lanza, G; Li, K S B; Maury Cuna, G H I; Métral, E; Papotti, G; Pieloni, T; Roncarolo, F; Salvant, B; Shaposhnikova, E N; Steinhagen, R J; Tavian, L J; Valuch, D; Venturini Delsolaro, W; Zimmermann, F; Iriso, U; Dominguez, O; Koukovini-Platia, E; Mounet, N; Zannini, C; Bhat, C M

    2011-01-01T23:59:59.000Z

    Operation of LHC with bunch trains at different spacings has revealed the formation of an electron cloud inside the machine. The main observations of electron cloud build up are the pressure rise measured at the vacuum gauges in the warm regions, as well as the increase of the beam screen temperature in the cold regions due to an additional heat load. The effects of the electron cloud were also visible as instability and emittance growth affecting the last bunches of longer trains, which could be improved running with higher chromaticity or larger transverse emittances. A summary of the 2010 and 2011 observations and measurements and a comparison with models will be presented. The efficiency of scrubbing to improve the machine running performance will be briefly discussed.

  15. Testing Cloud Microphysics Parameterizations in NCAR CAM5 with ISDAC and M-PACE Observations

    SciTech Connect (OSTI)

    Liu, Xiaohong; Xie, Shaocheng; Boyle, James; Klein, Stephen A.; Shi, Xiangjun; Wang, Zhien; Lin, Wuyin; Ghan, Steven J.; Earle, Michael; Liu, Peter; Zelenyuk, Alla

    2011-12-24T23:59:59.000Z

    Arctic clouds simulated by the NCAR Community Atmospheric Model version 5 (CAM5) are evaluated with observations from the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Indirect and Semi-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its North Slope of Alaska site in April 2008 and October 2004, respectively. Model forecasts for the Arctic Spring and Fall seasons performed under the Cloud- Associated Parameterizations Testbed (CAPT) framework generally reproduce the spatial distributions of cloud fraction for single-layer boundary layer mixed-phase stratocumulus, and multilayer or deep frontal clouds. However, for low-level clouds, the model significantly underestimates the observed cloud liquid water content in both seasons and cloud fraction in the Spring season. As a result, CAM5 significantly underestimates the surface downward longwave (LW) radiative fluxes by 20-40 W m-2. The model with a new ice nucleation parameterization moderately improves the model simulations by increasing cloud liquid water content in mixed-phase clouds through the reduction of the conversion rate from cloud liquid to ice by the Wegener-Bergeron- Findeisen (WBF) process. The CAM5 single column model testing shows that change in the homogeneous freezing temperature of rain to form snow from -5 C to -40 C has a substantial impact on the modeled liquid water content through the slowing-down of liquid and rain-related processes. In contrast, collections of cloud ice by snow and cloud liquid by rain are of minor importance for single-layer boundary layer mixed-phase clouds in the Arctic.

  16. Cloud Scavenging Effects on Aerosol Radiative and Cloud-nucleating Properties - Final Technical Report

    SciTech Connect (OSTI)

    Ogren, John A.; Sheridan, Patrick S.; Andrews, Elisabeth

    2009-03-05T23:59:59.000Z

    The optical properties of aerosol particles are the controlling factors in determining direct aerosol radiative forcing. These optical properties depend on the chemical composition and size distribution of the aerosol particles, which can change due to various processes during the particles’ lifetime in the atmosphere. Over the course of this project we have studied how cloud processing of atmospheric aerosol changes the aerosol optical properties. A counterflow virtual impactor was used to separate cloud drops from interstitial aerosol and parallel aerosol systems were used to measure the optical properties of the interstitial and cloud-scavenged aerosol. Specifically, aerosol light scattering, back-scattering and absorption were measured and used to derive radiatively significant parameters such as aerosol single scattering albedo and backscatter fraction for cloud-scavenged and interstitial aerosol. This data allows us to demonstrate that the radiative properties of cloud-processed aerosol can be quite different than pre-cloud aerosol. These differences can be used to improve the parameterization of aerosol forcing in climate models.

  17. Secure Cloud Computing With Brokered Trusted

    E-Print Network [OSTI]

    ) ·Audio ·QualComm 7201 528MHZ ·64MB Ram ·MicroSD Slow Storage ·Currently NO SIM CHIPS Monday, March 29 External Storage External Storage Router Router Router Router Cloud Computing Cloud Computing Cloud Storage External Storage Router Router Router Router Cloud Computing Cloud Computing Cloud Computing Tower

  18. Combustion Group Group members

    E-Print Network [OSTI]

    Wang, Wei

    Combustion Group Group members: Thierry Poinsot, Emilien Courtine, Luc Vervisch, Benjamin Farcy § New combustion and energy-conversion concepts #12;Introduction Combustion research thrusts Combustion Dynamics and Flame-Stabilization Research objectives § Obtain fundamental understanding of combustion

  19. Modeling Incoherent Electron Cloud Effects

    E-Print Network [OSTI]

    Benedetto, E.

    2008-01-01T23:59:59.000Z

    Benedetto, G. Franchetti, et al, PRL 97, 034801 (2006). E.K. Ohmi, F. Zimmermann, PRL 85, 3821 (2000). R.H. Siemann,

  20. Opaque cloud detection

    DOE Patents [OSTI]

    Roskovensky, John K. (Albuquerque, NM)

    2009-01-20T23:59:59.000Z

    A method of detecting clouds in a digital image comprising, for an area of the digital image, determining a reflectance value in at least three discrete electromagnetic spectrum bands, computing a first ratio of one reflectance value minus another reflectance value and the same two values added together, computing a second ratio of one reflectance value and another reflectance value, choosing one of the reflectance values, and concluding that an opaque cloud exists in the area if the results of each of the two computing steps and the choosing step fall within three corresponding predetermined ranges.

  1. Effects of aerosols on deep convective cumulus clouds

    E-Print Network [OSTI]

    Fan, Jiwen

    2009-05-15T23:59:59.000Z

    This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed...

  2. Retrieval of Cloud Microphysical Properties from MODIS and AIRS JUN LI,* HUNG-LUNG HUANG,* CHIAN-YI LIU,* PING YANG, TIMOTHY J. SCHMIT,# HELI WEI,

    E-Print Network [OSTI]

    Li, Jun

    ). Because clouds have such a large effect on the earth's radiation budget, even small changes), and effective cloud amount during both the daytime and the nighttime, as well as cloud particle size (CPS radiative transfer model for AIRS that accounts for cloud scattering and absorption is described

  3. Bondarenko method for obtaining group cross sections in a multi-region collision probability model

    E-Print Network [OSTI]

    Deinert, Mark

    the physics of nuclear reactors. In particular, the presence of resonances leads to the well-known self group cross sections derived this way with those produced by Monte Carlo simulations of thermal and fast spectrum reactors. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Hundreds of thousands

  4. Command Line Tools Cloud Computing

    E-Print Network [OSTI]

    Ferrara, Katherine W.

    Command Line Tools Cloud Computing #12;Everybody (or nearly everybody) loves GUI. AWS Command Line of advanced features. After surviving the cloud computing class till now, Your are almost a command line guru! You need AWS command line tools, ec2-api-tools, to maximize the power of AWS cloud computing. Plugging

  5. 8, 96979729, 2008 FRESCO+ cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 9697­9729, 2008 FRESCO+ cloud retrieval algorithm P. Wang et al. Title Page Abstract Chemistry and Physics Discussions FRESCO+: an improved O2 A-band cloud retrieval algorithm for tropospheric on behalf of the European Geosciences Union. 9697 #12;ACPD 8, 9697­9729, 2008 FRESCO+ cloud retrieval

  6. 3, 33013333, 2003 Cirrus cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 3, 3301­3333, 2003 Cirrus cloud occurrence as function of ambient relative humidity J. Str and Physics Discussions Cirrus cloud occurrence as function of ambient relative humidity: A comparison¨om (johan@itm.su.se) 3301 #12;ACPD 3, 3301­3333, 2003 Cirrus cloud occurrence as function of ambient

  7. Cloud Formation, Evolution and Destruction

    E-Print Network [OSTI]

    Estalella, Robert

    Chapter 4 Cloud Formation, Evolution and Destruction We now begin to trace the journey towards a star. How long does this take? The answer is surprisingly short: a good many clouds already contain new stars and these stars tend to be young. The typical cloud cannot spend long, if any time at all

  8. 5, 60136039, 2005 FRESCO cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 5, 6013­6039, 2005 FRESCO cloud algorithm N. Fournier et al. Title Page Abstract Introduction cloud information over deserts from SCIAMACHY O2 A-band N. Fournier 1 , P. Stammes 1 , M. de Graaf 1 , R, 6013­6039, 2005 FRESCO cloud algorithm N. Fournier et al. Title Page Abstract Introduction Conclusions

  9. NIST Cloud Computing Reference Architecture

    E-Print Network [OSTI]

    Perkins, Richard A.

    NIST Cloud Computing Reference Architecture Recommendations of the National Institute of Standards Publication 500-292 #12;i NIST Special Publication 500-292 NIST Cloud Computing Reference Architecture, John Messina, Lee Badger and Dawn Leaf Information Techonology Laboratory Cloud Computing Program

  10. The Magellanic Group and the Seven Dwarfs

    E-Print Network [OSTI]

    Elena D'Onghia; George Lake

    2008-09-22T23:59:59.000Z

    The Magellanic Clouds were the largest members of a group of dwarf galaxies that entered the Milky Way (MW) halo at late times. This group, dominated by the LMC, contained ~4% of the mass of the Milky Way prior to its accretion and tidal disruption, but ~70% of the known dwarfs orbiting the MW. Our theory addresses many outstanding problems in galaxy formation associated with dwarf galaxies. First, it can explain the planar orbital configuration populated by some dSphs in the MW. Second, it provides a mechanism for lighting up a subset of dwarf galaxies to reproduce the cumulative circular velocity distribution of the satellites in the MW. Finally, our model predicts that most dwarfs will be found in association with other dwarfs. The recent discovery of Leo V (Belokurov et al. 2008), a dwarf spheroidal companion of Leo IV, and the nearby dwarf associations supports our hypothesis.

  11. Global behavior of a multi-group SIS epidemic model with age ...

    E-Print Network [OSTI]

    2005-10-22T23:59:59.000Z

    Dec 10, 2004 ... Security Agency (NSA) and Alfred P. Sloan Foundation. ... into the model may provide additional and important information which may be ...

  12. Inverse Modeling and Geostatistics Project 17/04/2008DTU Geophysics research group meeting -2010-05-052 DTU Informatics, Technical University of Denmark

    E-Print Network [OSTI]

    Mosegaard, Klaus

    Inverse Modeling and Geostatistics Project #12;17/04/2008DTU Geophysics research group meeting Geophysics research group meeting - 2010-05-053 DTU Informatics, Technical University of Denmark Bayesian PROBLEM? #12;17/04/2008DTU Geophysics research group meeting - 2010-05-054 DTU Informatics, Technical

  13. Inverse Modeling and Geostatistics Project 17/04/2008DTU Geophysics research group meeting -2010-09-102 DTU Informatics, Technical University of Denmark

    E-Print Network [OSTI]

    Mosegaard, Klaus

    Inverse Modeling and Geostatistics Project #12;17/04/2008DTU Geophysics research group meetingModelingandGeostatisticsProject #12;17/04/2008DTU Geophysics research group meeting - 2010-09-103 DTU Informatics, Technical #12;17/04/2008DTU Geophysics research group meeting - 2010-09-105 DTU Informatics, Technical

  14. Final Report for grant DE-FG02-06ER54888, "Simulation of Beam-Electron Cloud Interactions in Circular Accelerators Using Plasma Models"

    SciTech Connect (OSTI)

    Decyk, Viktor K.

    2012-11-27T23:59:59.000Z

    The primary goal of this collaborative proposal was to modify the code QuickPIC and apply it to study the long-time stability of beam propagation in low density electron clouds present in circular accelerators. The UCLA contribution to this collaborative proposal was in supporting the development of the pipelining scheme for the QuickPIC code, which extended the parallel scaling of this code by two orders of magnitude.

  15. Stratocumulus Clouds ROBERT WOOD

    E-Print Network [OSTI]

    Wood, Robert

    by latent heating in updrafts and cooling in downdrafts. Turbulent eddies and evaporative cooling drives, stratification of the STBL, and in some cases cloud breakup. Feedbacks between radiative cooling, precipitation- way interactions may be a key driver of aerosol concentrations over the remote oceans. Aerosol

  16. Proceedings of the Thirty-ninth Meeting of the Agricultural Research Modellers' Group

    E-Print Network [OSTI]

    Maini, Philip K.

    of the University of Nottingham, was held in the Kohn Centre at the Royal Society, 6 Carlton House Terrace, London components of such `socio-ecological systems' (SESs), is necessary. Agent-based modelling is one approach the real thing. As a `socio-ecological' modeller, it was a great pleasure, therefore, to be asked to give

  17. Traversable wormholes in a string cloud

    E-Print Network [OSTI]

    Martin Richarte; Claudio Simeone

    2007-11-14T23:59:59.000Z

    We study spherically symmetric thin-shell wormholes in a string cloud background in (3+1)-dimensional spacetime. The amount of exotic matter required for the construction, the traversability and the stability under radial perturbations, are analyzed as functions of the parameters of the model. Besides, in the Appendices a non perturbative approach to the dynamics and a possible extension of the analysis to a related model are briefly discussed.

  18. A SEARCH FOR DUST EMISSION IN THE LEO INTERGALACTIC CLOUD

    SciTech Connect (OSTI)

    Bot, Caroline; Helou, George; Puget, Jeremie [California Institute of Technology, Pasadena, CA 91125 (United States); Latter, William B. [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Schneider, Stephen [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Terzian, Yervant [Department of Astronomy/NAIC, Cornell University, Ithaca, NY 14853 (United States)], E-mail: bot@astro.u-strasbg.fr

    2009-08-15T23:59:59.000Z

    We present a search for infrared dust emission associated with the Leo cloud, a large intergalactic cloud in the M96 group. Mid-infrared and far-infrared images were obtained with the InfraRed Array Camera and the Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope. Our analysis of these maps is done at each wavelength relative to the H I spatial distribution. We observe a probable detection at 8 {mu}m and a marginal detection at 24 {mu}m associated with the highest H I column densities in the cloud. At 70 and 160 {mu}m, upper limits on the dust emission are deduced. The level of the detection is low so that the possibility of a fortuitous cirrus clump or of an overdensity of extragalactic sources along the line of sight cannot be excluded. If this detection is confirmed, the quantities of dust inferred imply a dust-to-gas ratio in the intergalactic cloud up to a few times solar but no less than 1/20 solar. A confirmed detection would therefore exclude the possibility that the intergalactic cloud has a primordial origin. Instead, this large intergalactic cloud could therefore have been formed through interactions between galaxies in the group.

  19. Climate Dynamics Diagnosis of the Marine Low Cloud Simulation in the NCAR Community Earth System

    E-Print Network [OSTI]

    Bretherton, Chris

    -of-the-art coupled atmosphere-ocean models: the NCAR Community Earth System Model (CESM) and the NCEP Global of the Marine Low Cloud Simulation in the NCAR1 Community Earth System Model (CESM) and the NCEP Global2Climate Dynamics Diagnosis of the Marine Low Cloud Simulation in the NCAR Community Earth System

  20. EA-1852: Cloud County Community College Wind Energy Project,...

    Broader source: Energy.gov (indexed) [DOE]

    2: Cloud County Community College Wind Energy Project, Cloud County, Kansas EA-1852: Cloud County Community College Wind Energy Project, Cloud County, Kansas Summary This EA...

  1. LES Simulations of Roll Clouds Observed During Mixed- Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Greenberg, S.D.; Harrington, J.Y.; Prenni, A.; DeMott, P.

    2005-03-18T23:59:59.000Z

    Roll clouds, and associated roll convection, are fairly common features of the atmospheric boundary layer. While these organized cumuliform clouds are found over many regions of the planet, they are quite ubiquitous near the edge of the polar ice sheets. In particular, during periods of off-ice flow, when cold polar air flows from the ice pack over the relatively warm ocean water, strong boundary layer convection develops along with frequent rolls. According to Bruemmer and Pohlman (2000), most of the total cloud cover in the Arctic is due to roll clouds. In an effort to examine the influences of mixed-phase microphysics on the boundary layer evolution of roll clouds during off-ice flow, Olsson and Harrington (2000) used a 2D mesoscale model coupled to a bulk microphysical scheme (see Section 2). Their results showed that mixed-phase clouds produced more shallow boundary layers with weaker turbulence than liquid-phase cases. Furthermore, their results showed that because of th e reduced turbulent drag on the atmosphere in the mixed-phase case, regions of mesoscale divergence in the marginal ice-zone were significantly affected. A follow-up 2D study (Harrington and Olsson 2001) showed that the reduced turbulent intensity in mixed-phase cases was due to precipitation. Ice precipitation caused downdraft stabilization which fed back and caused a reduction in the surface heat fluxes. In this work, we extend the work of Olsson and Harrington (2000) and Harrington and Olsson (2001) by examining the impacts of ice microphysics on roll convection. We will present results that illustrate how microphysics alters roll cloud structure and dynamics.

  2. CloudSat Overview CloudSat will provide, from space, the first global survey of cloud profiles and

    E-Print Network [OSTI]

    on the radiative and water budgets of clouds are broadly referred to as indirect aerosol effects. The aerosol processes and their accumulated effects on the global scale. 2. Mission Description CloudSat is plannedCloudSat Overview CloudSat will provide, from space, the first global survey of cloud profiles

  3. Parameterizations of Cloud Microphysics and Indirect Aerosol Effects

    SciTech Connect (OSTI)

    Tao, Wei-Kuo [NASA/GSFC] [NASA/GSFC

    2014-05-19T23:59:59.000Z

    1. OVERVIEW Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 2001]. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds [NRC, 2001]." The aerosol effect on clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path [Twomey, 1977] and the "semi-direct" effect on cloud coverage [e.g., Ackerman et al., 2000]. Enhanced aerosol concentrations can also suppress warm rain processes by producing a narrow droplet spectrum that inhibits collision and coalescence processes [e.g., Squires and Twomey, 1961; Warner and Twomey, 1967; Warner, 1968; Rosenfeld, 1999]. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect [Albrecht, 1989], is even more complex, especially for mixed-phase convective clouds. Table 1 summarizes the key observational studies identifying the microphysical properties, cloud characteristics, thermodynamics and dynamics associated with cloud systems from high-aerosol continental environments. For example, atmospheric aerosol concentrations can influence cloud droplet size distributions, warm-rain process, cold-rain process, cloud-top height, the depth of the mixed phase region, and occurrence of lightning. In addition, high aerosol concentrations in urban environments could affect precipitation variability by providing an enhanced source of cloud condensation nuclei (CCN). Hypotheses have been developed to explain the effect of urban regions on convection and precipitation [van den Heever and Cotton, 2007 and Shepherd, 2005]. Recently, a detailed spectral-bin microphysical scheme was implemented into the Goddard Cumulus Ensemble (GCE) model. Atmospheric aerosols are also described using number density size-distribution functions. A spectral-bin microphysical model is very expensive from a computational point of view and has only been implemented into the 2D version of the GCE at the present time. The model is tested by studying the evolution of deep tropical clouds in the west Pacific warm pool region and summertime convection over a mid-latitude continent with different concentrations of CCN: a low "clean" concentration and a high "dirty" concentration. The impact of atmospheric aerosol concentration on cloud and precipitation will be investigated. 2. MODEL DESCRIPTION AND CASE STUDIES 2.1 GCE MODEL The model used in this study is the 2D version of the GCE model. Modeled flow is anelastic. Second- or higher-order advection schemes can produce negative values in the solution. Thus, a Multi-dimensional Positive Definite Advection Transport Algorithm (MPDATA) has been implemented into the model. All scalar variables (potential temperature, water vapor, turbulent coefficient and all five hydrometeor classes) use forward time differencing and the MPDATA for advection. Dynamic variables, u, v and w, use a second-order accurate advection scheme and a leapfrog time integration (kinetic energy semi-conserving method). Short-wave (solar) and long-wave radiation as well as a subgrid-scale TKE turbulence scheme are also included in the model. Details of the model can be found in Tao and Simpson (1993) and Tao et al. (2003). 2.2 Microphysics (Bin Model) The formulation of the explicit spectral-bin microphysical processes is based on solving stochastic kinetic equations for the size distribution functions of water droplets (cloud droplets and raindrops), and six types of ice particles: pristine ice crystals (columnar and plate-like), snow (dendrites and aggregates), graupel and frozen drops/hail. Each type is described by a special size distribution function containing 33 categories (bin

  4. Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report

    E-Print Network [OSTI]

    J. Butterworth; G. Dissertori; S. Dittmaier; D. de Florian; N. Glover; K. Hamilton; J. Huston; M. Kado; A. Korytov; F. Krauss; G. Soyez; J. R. Andersen; S. Badger; L. Barzč; J. Bellm; F. U. Bernlochner; A. Buckley; J. Butterworth; N. Chanon; M. Chiesa; A. Cooper-Sarkar; L. Cieri; G. Cullen; H. van Deurzen; G. Dissertori; S. Dittmaier; D. de Florian; S. Forte; R. Frederix; B. Fuks; J. Gao; M. V. Garzelli; T. Gehrmann; E. Gerwick; S. Gieseke; D. Gillberg; E. W. N. Glover; N. Greiner; K. Hamilton; T. Hapola; H. B. Hartanto; G. Heinrich; A. Huss; J. Huston; B. Jäger; M. Kado; A. Kardos; U. Klein; F. Krauss; A. Kruse; L. Lönnblad; G. Luisoni; Daniel Maître; P. Mastrolia; O. Mattelaer; J. Mazzitelli; E. Mirabella; P. Monni; G. Montagna; M. Moretti; P. Nadolsky; P. Nason; O. Nicrosini; C. Oleari; G. Ossola; S. Padhi; T. Peraro; F. Piccinini; S. Plätzer; S. Prestel; J. Pumplin; K. Rabbertz; Voica Radescu; L. Reina; C. Reuschle; J. Rojo; M. Schönherr; J. M. Smillie; J. F. von Soden-Fraunhofen; G. Soyez; R. Thorne; F. Tramontano; Z. Trocsanyi; D. Wackeroth; J. Winter; C-P. Yuan; V. Yundin; K. Zapp

    2014-05-05T23:59:59.000Z

    This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.

  5. Solar PV Manufacturing Cost Model Group: Installed Solar PV System Prices (Presentation)

    SciTech Connect (OSTI)

    Goodrich, A. C.; Woodhouse, M.; James, T.

    2011-02-01T23:59:59.000Z

    EERE's Solar Energy Technologies Program is charged with leading the Secretary's SunShot Initiative to reduce the cost of electricity from solar by 75% to be cost competitive with conventional energy sources without subsidy by the end of the decade. As part of this Initiative, the program has funded the National Renewable Energy Laboratory (NREL) to develop module manufacturing and solar PV system installation cost models to ensure that the program's cost reduction targets are carefully aligned with current and near term industry costs. The NREL cost analysis team has leveraged the laboratories' extensive experience in the areas of project finance and deployment, as well as industry partnerships, to develop cost models that mirror the project cost analysis tools used by project managers at leading U.S. installers. The cost models are constructed through a "bottoms-up" assessment of each major cost element, beginning with the system's bill of materials, labor requirements (type and hours) by component, site-specific charges, and soft costs. In addition to the relevant engineering, procurement, and construction costs, the models also consider all relevant costs to an installer, including labor burdens and overhead rates, supply chain costs, and overhead and materials inventory costs, and assume market-specific profits.

  6. The Magellan Final Report on Cloud Computing

    SciTech Connect (OSTI)

    ,; Coghlan, Susan; Yelick, Katherine

    2011-12-21T23:59:59.000Z

    The goal of Magellan, a project funded through the U.S. Department of Energy (DOE) Office of Advanced Scientific Computing Research (ASCR), was to investigate the potential role of cloud computing in addressing the computing needs for the DOE Office of Science (SC), particularly related to serving the needs of mid- range computing and future data-intensive computing workloads. A set of research questions was formed to probe various aspects of cloud computing from performance, usability, and cost. To address these questions, a distributed testbed infrastructure was deployed at the Argonne Leadership Computing Facility (ALCF) and the National Energy Research Scientific Computing Center (NERSC). The testbed was designed to be flexible and capable enough to explore a variety of computing models and hardware design points in order to understand the impact for various scientific applications. During the project, the testbed also served as a valuable resource to application scientists. Applications from a diverse set of projects such as MG-RAST (a metagenomics analysis server), the Joint Genome Institute, the STAR experiment at the Relativistic Heavy Ion Collider, and the Laser Interferometer Gravitational Wave Observatory (LIGO), were used by the Magellan project for benchmarking within the cloud, but the project teams were also able to accomplish important production science utilizing the Magellan cloud resources.

  7. Microphysical Properties of Clouds with Low Liquid Water Paths: An Update from Clouds with Low Optical (Water) Depth

    SciTech Connect (OSTI)

    Turner, D.D.; Flynn, C.; Long, C.; McFarlane, S.; Vogelmann, A.; Johnson, K.; Miller, M.; Chiu, C.; Marshak, A.; Wiscombe, W.; Clough, S.A.; Heck, P.; Minnis, P.; Liljegren, J.; Min, Q.; O'Hirok, W.; Wang, Z.

    2005-03-18T23:59:59.000Z

    Clouds play a critical role in the modulation of the radiative transfer in the atmosphere, and how clouds interact with radiation is one of the primary uncertainties in global climate models (GCMs). To reduce this uncertainty, the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program collects an immense amount of data from its Climate Research Facilities (CRFs); these data include observations of radiative fluxes, cloud properties from active and passive remote sensors, upper atmospheric soundings, and other observations. The program's goal is to use these coincident, longterm observations to improve the parameterization of radiative transfer in clear and cloudy atmospheres in GCMs.

  8. Study of Mechanisms of Aerosol Indirect Effects on Glaciated Clouds: Progress during the Project Final Technical Report

    SciTech Connect (OSTI)

    None

    2013-10-18T23:59:59.000Z

    This 3-year project has studied how aerosol pollution influences glaciated clouds. The tool applied has been an 'aerosol-cloud model'. It is a type of Cloud-System Resolving Model (CSRM) modified to include 2-moment bulk microphysics and 7 aerosol species, as described by Phillips et al. (2009, 2013). The study has been done by, first, improving the model and then performing sensitivity studies with validated simulations of a couple of observed cases from ARM. These are namely the Tropical Warm Pool International Cloud Experiment (TWP-ICE) over the tropical west Pacific and the Cloud and Land Surface Interaction Campaign (CLASIC) over Oklahoma. During the project, sensitivity tests with the model showed that in continental clouds, extra liquid aerosols (soluble aerosol material) from pollution inhibited warm rain processes for precipitation production. This promoted homogeneous freezing of cloud droplets and aerosols. Mass and number concentrations of cloud-ice particles were boosted. The mean sizes of cloud-ice particles were reduced by the pollution. Hence, the lifetime of glaciated clouds, especially ice-only clouds, was augmented due to inhibition of sedimentation and ice-ice aggregation. Latent heat released from extra homogeneous freezing invigorated convective updrafts, and raised their maximum cloud-tops, when aerosol pollution was included. In the particular cases simulated in the project, the aerosol indirect effect of glaciated clouds was twice than of (warm) water clouds. This was because glaciated clouds are higher in the troposphere than water clouds and have the first interaction with incoming solar radiation. Ice-only clouds caused solar cooling by becoming more extensive as a result of aerosol pollution. This 'lifetime indirect effect' of ice-only clouds was due to higher numbers of homogeneously nucleated ice crystals causing a reduction in their mean size, slowing the ice-crystal process of snow production and slowing sedimentation. In addition to the known indirect effects (glaciation, riming and thermodynamic), new indirect effects were discovered and quantified due to responses of sedimentation, aggregation and coalescence in glaciated clouds to changing aerosol conditions. In summary, the change in horizontal extent of the glaciated clouds ('lifetime indirect effects'), especially of ice-only clouds, was seen to be of higher importance in regulating aerosol indirect effects than changes in cloud properties ('cloud albedo indirect effects').

  9. 396 Journal of the Meteorological Society of Japan Vol. 60, No. 1 Cloud Clusters and Large-Scale Vertical Motions

    E-Print Network [OSTI]

    Houze Jr., Robert A.

    an important absorber and emitter of radiation. Radiative transfer models applied to tropical cloud shields, its net effect on the large-scale heat budget changes. As the cloud shield develops, the meso- scale, it is concluded that the mesoscale stratiform and radiative processes associated with the cloud shields

  10. Cloud climatology at the Southern Great Plains and the layer structure, drizzle, and atmospheric modes of continental stratus

    E-Print Network [OSTI]

    of cloud layers, an issue that is important in calculating both the radiative and the hydro- logic effects.5 years) cloud observations from the Atmospheric Radiation Measurements (ARM) program Southern Great in Global Climate Models (GCMs) remains a source of uncertainty in climate simulations. Cloud climatologies

  11. Zero modes' fusion ring and braid group representations for the extended chiral su(2) WZNW model

    E-Print Network [OSTI]

    P. Furlan; L. Hadjiivanov; I. Todorov

    2008-04-24T23:59:59.000Z

    The zero modes' Fock space for the extended chiral $su(2)$ WZNW model gives room to a realization of the Grothendieck fusion ring of representations of the restricted $U_q sl(2)$ quantum universal enveloping algebra (QUEA) at an even ($2h$-th) root of unity, and of its extension by the Lusztig operators. It is shown that expressing the Drinfeld images of canonical characters in terms of Chebyshev polynomials of the Casimir invariant $C$ allows a streamlined derivation of the characteristic equation of $C$ from the defining relations of the restricted QUEA. The properties of the fusion ring of the Lusztig's extension of the QUEA in the zero modes' Fock space are related to the braiding properties of correlation functions of primary fields of the extended $su(2)_{h-2}$ current algebra model.

  12. A Catalog of HI Clouds in the Large Magellanic Cloud

    E-Print Network [OSTI]

    S. Kim; E. Rosolowsky; Y. Lee; Y. Kim; Y. C. Jung; M. A. Dopita; B. G. Elmegreen; K. C. Freeman; R. J. Sault; M. J. Kesteven; D. McConnell; Y. -H. Chu

    2007-06-28T23:59:59.000Z

    A 21 cm neutral hydrogen interferometric survey of the Large Magellanic Cloud (LMC) combined with the Parkes multi-beam HI single-dish survey clearly shows that the HI gas is distributed in the form of clumps or clouds. The HI clouds and clumps have been identified using a thresholding method with three separate brightness temperature thresholds ($T_b$). Each catalog of HI cloud candidates shows a power law relationship between the sizes and the velocity dispersions of the clouds roughly following the Larson Law scaling $\\sigma_v \\propto R^{0.5}$, with steeper indices associated with dynamically hot regions. The clouds in each catalog have roughly constant virial parameters as a function mass suggesting that that the clouds are all in roughly the same dynamical state, but the values of the virial parameter are significantly larger than unity showing that turbulent motions dominate gravity in these clouds. The mass distribution of the clouds is a power law with differential indices between -1.6 and -2.0 for the three catalogs. In contrast, the distribution of mean surface densities is a log-normal distribution.

  13. Broken and inhomogeneous cloud impact on satellite cloud particle effective radius and cloudphase retrievals

    E-Print Network [OSTI]

    Stoffelen, Ad

    on the particle size distribution, height, and thermo- dynamic phase of clouds. Water and ice clouds have parameterizations is the global dis- tribution of cloud thermodynamic phase, i.e., whether a cloud is composed on satellitederived cloud particle effective radius (re) and cloud phase (CPH) for broken and overcast inhomogeneous

  14. The Formation of the Oort Cloud in Open Cluster Environments

    E-Print Network [OSTI]

    Nathan A. Kaib; Thomas Quinn

    2008-04-02T23:59:59.000Z

    We study the influence of an open cluster environment on the formation and current structure of the Oort cloud. To do this, we have run 19 different simulations of the formation of the Oort Cloud for 4.5 Gyrs. In each simulation, the solar system spends its first 100 Myrs in a different open cluster environment before transitioning to its current field environment. We find that, compared to forming in the field environment, the inner Oort Cloud is preferentially loaded with comets while the Sun resides in the open cluster and that most of this material remains locked in the interior of the cloud for the next 4.4 Gyrs. In addition, the outer Oort Cloud trapping efficiencies we observe in our simulations are lower than previous formation models by about a factor of 2, possibly implying an even more massive early planetesimal disk. Furthermore, some of our simulations reproduce the orbits of observed extended scattered disk objects, which may serve as an observational constraint on the Sun's early environment. Depending on the particular open cluster environment, the properties of the inner Oort Cloud and extended scattered disk can vary widely. On the other hand, the outer portions of the Oort Cloud in each of our simulations are all similar.

  15. Modeling and Analysis of CSP Systems (Fact Sheet), Thermal Systems Group: CSP Capabilities (TSG)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA /Ml'. William Hirst HirstModelingAssessing the Solar

  16. Working Group Reports Calibration of Radiation Codes Used in Climate Models:

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat is abigpresented in theWorkBusiness1: Model4:97

  17. Working Group Reports Summary of Single-Column Model Intensive Observation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat is abigpresented in theWorkBusiness1: Model4:97

  18. A confirmed location in the Galactic halo for the high-velocity cloud 'chain A'

    E-Print Network [OSTI]

    Hugo van Woerden; Ulrich J. Schwarz; Reynier F. Peletier; Bart P. Wakker; Peter M. W. Kalberla

    1999-07-08T23:59:59.000Z

    The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^6 solar masses.

  19. A confirmed location in the Galactic halo for the high-velocity cloud "chain A"

    E-Print Network [OSTI]

    Van Woerden, H; Peletier, R F; Wakker, B P; Kalberla, P M W; Woerden, Hugo van; Schwarz, Ulrich J.; Peletier, Reynier F.; Wakker, Bart P.; Kalberla, Peter M.W.

    1999-01-01T23:59:59.000Z

    The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^...

  20. On the Role of Massive Stars in the Support and Destruction of Giant Molecular Clouds

    E-Print Network [OSTI]

    Christopher D. Matzner

    2002-02-01T23:59:59.000Z

    We argue that massive stars are the dominant sources of energy for the turbulent motions within giant molecular clouds, and that the primary agent of feedback is the expansion of H II regions within the cloud volume. This conclusion is suggested by the low efficiency of star formation and corroborated by dynamical models of H II regions. We evaluate the turbulent energy input rate in clouds more massive than one third of a million solar masses, for which gravity does not significantly affect the expansion of H II regions. Such clouds achieve a balance between the decay of turbulent energy and its regeneration in H II regions; summed over clouds, the implied ionizing luminosity and star formation rate are roughly consistent with the Galactic total. H II regions also photoevaporate their clouds: we derive cloud destruction times somewhat shorter than those estimated by Williams and McKee. The upper mass limit for molecular clouds in the Milky Way may derive from the fact that larger clouds would destroy themselves in less than one crossing time. The conditions within starburst galaxies do not permit giant molecular clouds to be supported or destroyed by H II regions. This should lead to rapid cloud collapse and the efficient formation of massive star clusters, explaining some aspects of the starburst phenomenon.

  1. Group effects on fuel NOx emissisons from coal

    E-Print Network [OSTI]

    Vadakkath, Anand Anakkara

    1991-01-01T23:59:59.000Z

    . 18 N to NO Conversion vs G Number via Volatiles . 55 56 19 N to NO Conversion vs G Number by Burn-out. . . 20 N to NO Conversion vs G Number by All Methods . 57 21 N to NO Conversion vs G number for Two Coal Diameters 60 Figure Page 22 N... Ratio of GC Rate to ISOC Rate versus G Number (Annamalai) 17 8 Group Combustion Model for a. Spherical Coal Cloud 20 9 Flow-chart for the Program 32 10 Experimental Set-up . 11 Water Cooled Collection System . 40 12 Connections for NOx Analyzer . 42...

  2. Cicada: Predictive Guarantees for Cloud Network Bandwidth

    E-Print Network [OSTI]

    LaCurts, Katrina

    2014-03-24T23:59:59.000Z

    In cloud-computing systems, network-bandwidth guarantees have been shown to improve predictability of application performance and cost. Most previous work on cloud-bandwidth guarantees has assumed that cloud tenants know ...

  3. Electron-Cloud Build-Up: Summary

    E-Print Network [OSTI]

    Furman, M.A.

    2007-01-01T23:59:59.000Z

    Properties In?uencing Electron Cloud Phenomena,” Appl. Surf.Dissipation of the Electron Cloud,” Proc. PAC03 (Portland,is no signi?cant electron-cloud under nominal operating

  4. Magellan: experiences from a Science Cloud

    E-Print Network [OSTI]

    Ramakrishnan, Lavanya

    2013-01-01T23:59:59.000Z

    2010. From Clusters To Clouds: xCAT 2 Is Out Of The Bag.Cost of Doing Science on the Cloud: The Montage Example. Incost of doing science on the cloud: the montage example. In

  5. The Cloud Computing and Other Variables

    E-Print Network [OSTI]

    Borjon-Kubota, Martha Estela

    2011-01-01T23:59:59.000Z

    12. Fragments in Six 13. Cloud Computing 14. Phase 15.Note 48. Devoured vi Cloud Computing and other Variables I.moment. Lasts hours. Cloud Computing Just there Over the

  6. The Magellan Final Report on Cloud Computing

    E-Print Network [OSTI]

    Coghlan, Susan

    2013-01-01T23:59:59.000Z

    4.3.1 Cloud Computing Attractive Features . 4.3.2A berkeley view of cloud computing. Technical Report UCB/matching computations on cloud computing platforms and hpc

  7. Impacts of anthropogenic aerosol and greenhouse gas emissions on clouds, convection, and precipitation as simulated by a super-parameterized global climate model /

    E-Print Network [OSTI]

    Kooperman, Gabriel J.

    2014-01-01T23:59:59.000Z

    2 coupled Community Earth System Model simulations. The meancoupled NCAR Community Earth System Model (CESM), which alsoPrediction using Earth System Models Program, the National

  8. Improvements in Near-Terminator and Nocturnal Cloud Masks using Satellite Imager Data over the Atmospheric Radiation Measurement Sites

    SciTech Connect (OSTI)

    Trepte, Q.Z.; Minnis, P.; Heck, P.W.; Palikonda, R.

    2005-03-18T23:59:59.000Z

    Cloud detection using satellite measurements presents a big challenge near the terminator where the visible (VIS; 0.65 {micro}m) channel becomes less reliable and the reflected solar component of the solar infrared 3.9-{micro}m channel reaches very low signal-to-noise ratio levels. As a result, clouds are underestimated near the terminator and at night over land and ocean in previous Atmospheric Radiation Measurement (ARM) Program cloud retrievals using Geostationary Operational Environmental Satellite (GOES) imager data. Cloud detection near the terminator has always been a challenge. For example, comparisons between the CLAVR-x (Clouds from Advanced Very High Resolution Radiometer [AVHRR]) cloud coverage and Geoscience Laser Altimeter System (GLAS) measurements north of 60{sup o}N indicate significant amounts of missing clouds from AVHRR because this part of the world was near the day/night terminator viewed by AVHRR. Comparisons between MODIS cloud products and GLAS at the same regions also shows the same difficulty in the MODIS cloud retrieval (Pavolonis and Heidinger 2005). Consistent detection of clouds at all times of day is needed to provide reliable cloud and radiation products for ARM and other research efforts involving the modeling of clouds and their interaction with the radiation budget. To minimize inconsistencies between daytime and nighttime retrievals, this paper develops an improved twilight and nighttime cloud mask using GOES-9, 10, and 12 imager data over the ARM sites and the continental United States (CONUS).

  9. Cloud of strings for radiating black holes in Lovelock gravity

    E-Print Network [OSTI]

    Sushant G. Ghosh; Sunil D. Maharaj

    2014-09-28T23:59:59.000Z

    We present exact spherically symmetric null dust solutions in the third order Lovelock gravity with a string cloud background in arbitrary $N$ dimensions,. This represents radiating black holes and generalizes the well known Vaidya solution to Lovelock gravity with a string cloud in the background. We also discuss the energy conditions and horizon structures, and explicitly bring out the effect of the string clouds on the horizon structure of black hole solutions for the higher dimensional general relativity and Einstein-Gauss-Bonnet theories. It turns out that the presence of the coupling constant of the Gauss-Bonnet terms and/or background string clouds completely changes the structure of the horizon and this may lead to a naked singularity. We recover known spherically symmetric radiating models as well as static black holes in the appropriate limits.

  10. Sunlight Changes Aerosols in Clouds | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sunlight Changes Aerosols in Clouds Sunlight Changes Aerosols in Clouds Released: October 20, 2011 Scientists show how sunlight alters optical, chemical properties of atmospheric...

  11. 3, 44614488, 2003 Cloud particle

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    effects. On one hand, clouds reflect the incoming solar radiation and thus cool the Earth significant effect on the radiation balance (Wielicki et al, 1996; Mitchell, 1989) due to two competing-Atmosphere system. On the other hand, clouds absorb longwave thermal radiation coming from the surface and then re

  12. Tropical Cloud Properties and Radiative Heating Profiles

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Mather, James

    We have generated a suite of products that includes merged soundings, cloud microphysics, and radiative fluxes and heating profiles. The cloud microphysics is strongly based on the ARM Microbase value added product (Miller et al., 2003). We have made a few changes to the microbase parameterizations to address issues we observed in our initial analysis of the tropical data. The merged sounding product is not directly related to the product developed by ARM but is similar in that it uses the microwave radiometer to scale the radiosonde column water vapor. The radiative fluxes also differ from the ARM BBHRP (Broadband Heating Rate Profile) product in terms of the radiative transfer model and the sampling interval.

  13. ROSAT Observations of Compact Groups of Galaxies

    E-Print Network [OSTI]

    P. Saracco; P. Ciliegi

    1994-12-15T23:59:59.000Z

    A search for X-ray emission from compact groups revealed detection from 8 out of the 12 HCG images extracted from the ROSAT public archive. For two of them the X-ray emission originates from galaxies in the group. On the contrary, three groups show an extended emission clearly caused by hot intracluster gas. A Raymond-Smith hot plasma model provides an excellent fit to the X-ray spectra. The estimated temperatures are distributed in a quite narrow range (from 0.73 to 0.92 keV) and are consistent, within the errors, with 0.9 keV. The luminosity ranging from 0.75 to $5.1\\cdot10^{42}$erg s$^{-1}$. The most relevant result is the low metal abundance surely detected in two of them and likely in a third that characterizes the hot gas cloud responsible for the X-ray emission. The data concerning the remaining 3 detected compact groups are not sufficient to discriminate with certainty between diffuse and/or point-like X-ray emission. However the results of the spectral analysis point to the presence of a hot gas again with low metal abundance.

  14. Cloud Remote Sensing with Sideways-Looks : Theory and First Results Using Multispectral Thermal Imager Data

    SciTech Connect (OSTI)

    Davis, A. B. (Anthony B.)

    2002-01-01T23:59:59.000Z

    In operational remote sensing, the implicit model for cloud geometry is a homogeneous plane-parallel slab of infinite horizontal extent. Each pixel is indeed processed as if it exchanged no radiant energy whatsoever with its neighbors. The shortcomings of this conceptual model have been well documented in the specialized literature but rarely mitigated. The worst-case scenario is probably high-resolution imagery where dense isolated clouds are visible, often both bright (reflective) and dark (transmissive) sides being apparent from the same satellite viewing angle: the low transmitted radiance could conceivably be interpreted in plane-parallel theory as no cloud at all. An alternative to the plane-parallel cloud model is introduced here that has the same appeal of being analytically tractable, at least in the diffusion limit: the spherical cloud. This new geometrical paradigm is applied to radiances from cumulus clouds captured by DOE's Multispectral Thermal Imager (MTI). Estimates of isolated cloud opacities are a necessary first step in correcting radiances from surface targets that are visible in the midst of a broken-cloud field. This type of advanced atmospheric correction is badly needed in remote sensing applications such as nonproliferation detection were waiting for a cloud-free look in the indefinite future is not a viable option.

  15. Microphysical Effects Determine Macrophysical Response for Aerosol Impacts on Deep Convective Clouds

    SciTech Connect (OSTI)

    Fan, Jiwen; Leung, Lai-Yung R.; Rosenfeld, Daniel; Chen, Qian; Li, Zhanqing; Zhang, Jinqiang; Yan, Hongru

    2013-11-26T23:59:59.000Z

    Deep convective clouds (DCCs) play a crucial role in the general circulation and energy and hydrological cycle of our climate system. Anthropogenic and natural aerosol particles can influence DCCs through changes in cloud properties, precipitation regimes, and radiation balance. Modeling studies have reported both invigoration and suppression of DCCs by aerosols, but none has fully quantified aerosol impacts on convection life cycle and radiative forcing. By conducting multiple month-long cloud-resolving simulations with spectral-bin cloud microphysics that capture the observed macro- and micro-physical properties of summer convective clouds in the tropics and mid-latitudes, this study provides the first comprehensive look at how aerosols affect cloud cover, cloud top height (CTH), and radiative forcing. Observations validate these simulation results. We find that microphysical aerosol effects contribute predominantly to increased cloud cover and CTH by inducing larger amount of smaller but longer lasting ice particles in the stratiform/anvils of DCCs with dynamical aerosol effects contributing at most ~ 1/4 of the total increase of cloud cover. The overall effect is a radiative warming in the atmosphere (3 to 5 W m-2) with strong surface cooling (-5 to -8 W m-2). Herein we clearly identified mechanisms more important than and additional to the invigoration effects hypothesized previously that explain the consistent signatures of increased cloud tops area and height by aerosols in DCCs revealed by observations.

  16. Cloud feedback studies with a physics grid

    SciTech Connect (OSTI)

    Dipankar, Anurag [Max Planck Institute for Meteorology Hamburg; Stevens, Bjorn [Max Planck Institute for Meteorology Hamburg

    2013-02-07T23:59:59.000Z

    During this project the investigators implemented a fully parallel version of dual-grid approach in main frame code ICON, implemented a fully conservative first-order interpolation scheme for horizontal remapping, integrated UCLA-LES micro-scale model into ICON to run parallely in selected columns, and did cloud feedback studies on aqua-planet setup to evaluate the classical parameterization on a small domain. The micro-scale model may be run in parallel with the classical parameterization, or it may be run on a "physics grid" independent of the dynamics grid.

  17. The dynamics and high-energy emission of conductive gas clouds in supernova-driven galactic superwinds

    E-Print Network [OSTI]

    A. Marcolini; D. K. Strickland; A. D'Ercole; T. M. Heckman; C. G. Hoopes

    2005-06-27T23:59:59.000Z

    In this paper we present high-resolution hydrodynamical models of warm ionized clouds embedded in a superwind, and compare the OVI and soft X-ray properties to the existing observational data. These models include thermal conduction, which we show plays an important role in shaping both the dynamics and radiative properties of the resulting wind/cloud interaction. Heat conduction stabilizes the cloud by inhibiting the growth of K-H and R-T instabilities, and also generates a shock wave at the cloud's surface that compresses the cloud. This dynamical behaviour influences the observable properties. We find that while OVI emission and absorption always arises in cloud material at the periphery of the cloud, most of the soft X-ray arises in the region between the wind bow shock and the cloud surface, and probes either wind or cloud material depending on the strength of conduction and the relative abundances of the wind with respect to the cloud. In general only a small fraction (thermal conduction, in particular in terms of the OVI-to-X-ray luminosity ratio, but cloud life times are uncomfortably short (thermal conductivity and found that even when we reduced conduction by a factor of 25 that the simulations retained the beneficial hydrodynamical stability and low O{\\sc vi}-to-X-ray luminosity ratio found in the Spitzer-level conductive models, while also having reduced evaporation rates.

  18. Observable consequences of cold clouds as dark matter

    E-Print Network [OSTI]

    E. Kerins; J. Binney; J. Silk

    2002-01-10T23:59:59.000Z

    Cold, dense clouds of gas have been proposed as baryonic candidates for the dark matter in Galactic haloes, and have also been invoked in the Galactic disc as an explanation for the excess faint sub-mm sources detected by SCUBA. Even if their dust-to-gas ratio is only a small percentage of that in conventional gas clouds, these dense systems would be opaque to visible radiation. This presents the possibility of detecting them by looking for occultations of background stars. We examine the possibility that the data sets of microlensing experiments searching for massive compact halo objects can also be used to search for occultation signatures by cold clouds. We compute the rate and timescale distribution of stellar transits by clouds in the Galactic disc and halo. We find that, for cloud parameters typically advocated by theoretical models, thousands of transit events should already exist within microlensing survey data sets. We examine the seasonal modulation in the rate caused by the Earth's orbital motion and find it provides an excellent probe of whether detected clouds are of disc or halo origin.

  19. Algebraic and group structure for bipartite three dimensional anisotropic Ising model on a non-local basis

    E-Print Network [OSTI]

    Francisco Delgado

    2014-10-28T23:59:59.000Z

    Entanglement is considered as a basic physical resource for modern quantum applications in Quantum Information and Quantum Computation theories. Interactions able to generate and sustain entanglement are subject to deep research in order to have understanding and control on it, based on specific physical systems. Atoms, ions or quantum dots are considered a key piece in quantum applications because is a basic piece of developments towards a scalable spin-based quantum computer through universal and basic quantum operations. Ising model is a type of interaction which generates and modi?es entanglement properties of quantum systems based on matter. In this work, a general anisotropic three dimensional Ising model including an inhomogeneous magnetic field is analyzed to obtain their evolution and then, their algebraic properties which are controlled through a set of physical parameters. Evolution denote remarkable group properties when is analyzed in a non local basis, in particular those related with entanglement. These properties give a fruitful arena for further quantum applications and their control.

  20. The B and W Owners Group program for microstructural characterization and radiation embrittlement modelling of Linde 80 reactor vessel welds

    SciTech Connect (OSTI)

    Pavinich, W.A. [Grove Engineering, Knoxville, TN (United States); Harbison, L.S. [B and W Nuclear Technologies, Lynchburg, VA (United States)

    1996-12-31T23:59:59.000Z

    The Babcock and Wilcox Owners Group (B and WOG) is embrittlement of Linde 80 reactor vessel welds from a micro-mechanical viewpoint. Previous work that focused on characterizing the large microstructural features indicated that a large portion of the bulk copper content is in precipitate/inclusion/carbide form. This result indicates that copper in solid solution is considerably less than the bulk composition. Field-ion microscope atom probe investigations on unirradiated weld metals with bulk copper contents ranging from 0.22 to 0.38 wt%, also indicate significant amount of copper are tied up in precipitate/inclusion/carbide form. This results is significant since the bulk copper content (which includes both copper in solid solution and copper contained in precipitates, inclusions, and carbides) is used in Regulatory Guide 1.99, Revision 2 to determine radiation damage. This paper reviews these results. Existing radiation embrittlement models superpose the changes in yield strength due to defect clusters and copper-rich precipitates induced by neutron irradiation. Low-copper Linde 80 welds display little or no increase in the 41 joule (30 ft-lb) transition temperature as a result of neutron irradiation which indicates that precipitation is the dominant component of radiation embrittlement for Linde 80 welds. Future work will include further microstructural characterizations of Linde 80 reactor vessel welds and applying the existing radiation embrittlement models to Linde 80 welds. This paper describes the detailed plans for future work.

  1. Platform for Hybrid Cloud Technical White Paper

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Platform for Hybrid Cloud Technical White Paper Published: September 2013 (updated) Applies to: SQL Server and Windows Azure Summary: Cloud computing brings a new paradigm shift in computing in the cloud with greater scale and flexibility. Microsoft SQL Server runs very well in the cloud environment

  2. Cloud Computing An enterprise perspective Raghavan Subramanian

    E-Print Network [OSTI]

    Rajamani, Sriram K.

    Cloud Computing ­ An enterprise perspective Raghavan Subramanian Infosys Technologies Limited #12;2Infosys Confidential Overview of cloud computing? Cloud computing* Computing in which dynamically scalable of cloud computing 1. On-demand self-service 2. Ubiquitous network access 3. Location independent resource

  3. IBM Software Solution Brief Safeguarding the cloud

    E-Print Network [OSTI]

    IBM Software Solution Brief Safeguarding the cloud with IBM Security solutions Maintain visibility and control with proven security solutions for public, private and hybrid clouds Highlights Address cloud internal and external users, data, applications and workloads as they move to and from the cloud Regain

  4. 7, 1711717146, 2007 Dependence of cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 7, 17117­17146, 2007 Dependence of cloud fraction and cloud height on temperature T. Wagner et a Creative Commons License. Atmospheric Chemistry and Physics Discussions Dependence of cloud fraction and cloud top height on surface temperature derived from spectrally resolved UV/vis satellite observations T

  5. Cloud Data Management (CDM) Yunpeng Chai

    E-Print Network [OSTI]

    /W performance / Parallelism No/ Simple SQL operations 12 /26 Survey of CDM Cloud Storage: Architecture: Master#12;Cloud Data Management (CDM) Yunpeng Chai 2 /26 Outline Motivation of CDM Survey of CDM IBM SUR Cloud China Mobile National Health Care #12;9 /26 Outline Motivation of CDM Survey of CDM IBM SUR Cloud

  6. 6, 43414373, 2006 Cloud-borne aerosol

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Discussions Impact of cloud-borne aerosol representation on aerosol direct and indirect effects S. J. Ghan of aerosols employ a variety of rep- resentations of such cloud-borne particles. Here we use a global aerosol- ulated aerosol, cloud and radiation fields to various approximations to the representa- tion of cloud

  7. Vision: Cloud-Powered Sight for All Showing the Cloud What You See

    E-Print Network [OSTI]

    Zhong, Lin

    Vision: Cloud-Powered Sight for All Showing the Cloud What You See Paramvir Bahl Matthai Philipose argue that for computers to do more for us, we need to show the cloud what we see and embrace cloud General Terms Algorithms, Design, Human Factors, Languages, Performance, Security Keywords Camera, cloud

  8. CLOUD, DRIZZLE, AND TURBULENCE OBSERVATIONS IN MARINE STRATOCUMULUS CLOUDS IN THE AZORES

    E-Print Network [OSTI]

    CLOUD, DRIZZLE, AND TURBULENCE OBSERVATIONS IN MARINE STRATOCUMULUS CLOUDS IN THE AZORES Jasmine at the Azores provided a unique, long-term record (May 2009 to December 2010) of cloud observations in a regime dominated by low-level stratiform clouds. First, a comprehensive cloud classification scheme that utilizes

  9. Cloud Futures Workshop 2010 Cloud Computing Support for Massively Social Gaming Alexandru Iosup

    E-Print Network [OSTI]

    Iosup, Alexandru

    1 Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming Alexandru Iosup Pierre (Vrije U.). Cloud Computing Support for Massively Social Gaming (Rain for the Thirsty) #12;Cloud Futures Workshop 2010 ­ Cloud Computing Support for Massively Social Gaming 2 Intermezzo: Tips on how

  10. Changes in Cloud Cover and Cloud Types Over the Ocean from Surface

    E-Print Network [OSTI]

    Hochberg, Michael

    Total cloud cover 54 68 Clear sky (frequency) 22 3 #12;Low Clouds & Solar Radiation Low clouds scatterChanges in Cloud Cover and Cloud Types Over the Ocean from Surface Observations, 1954-2008 Ryan This produces a weak net warming effect in the atmosphere, since more radiation comes in, and less goes out

  11. Decomposing aerosol cloud radiative effects into cloud cover, liquid water path and Twomey components

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Decomposing aerosol cloud radiative effects into cloud cover, liquid water path and Twomey interactions radiative effects, i.e., the cloud cover, liquid water path (LWP) and cloud drop radius (Twomey negative radiative forcing on the global scale, mainly due to the cloud cover effect. © 2013 Elsevier B

  12. A Survey of Changes in Cloud Cover and Cloud Types over Land from Surface Observations, 197196

    E-Print Network [OSTI]

    Hochberg, Michael

    of their effects on solar radiation, terrestrial radiation, and precipitation. These effects depend on cloud height, and the season of the year and time of day. The effect of clouds on the earth's radiation budget, the "cloud to be a useful classification in studies of cloud processes (Houze 1993). The climatic effects of clouds further

  13. CHEMICAL SIGNATURE OF A MAJOR MERGER IN THE EARLY FORMATION OF THE SMALL MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory, Mitaka-shi, Tokyo 181-8588 (Japan); Bekki, Kenji [School of Physics, University of New South Wales, Sydney 2052, NSW (Australia)], E-mail: taku.tsujimoto@nao.ac.jp

    2009-08-01T23:59:59.000Z

    The formation history of the Small Magellanic Cloud (SMC) is unraveled based on the results of our new chemical evolution models constructed for the SMC, highlighting the observed anomaly in the age-metallicity relation for star clusters in the SMC. We first propose that evidence of a major merger is imprinted in the age-metallicity relation as a dip in [Fe/H]. Our models predict that the major merger with a mass ratio of 1:1 to 1:4 occurred at {approx}7.5 Gyr ago, with a good reproduction of the abundance distribution function of field stars in the SMC. Furthermore, our models predict a relatively large scatter in [Mg/Fe] for -1.4 {<=} [Fe/H] {<=} -1.1 as a reflection of a looping feature resulting from the temporally inverse progress of chemical enrichment, which can be tested against future observational results. Given that the observed velocity dispersion ({approx}30 km s{sup -1}) of the SMC is much smaller than that ({approx}160 km s{sup -1}) of the Galactic halo, our finding strongly implies that the predicted merger event happened in a small group environment that was far from the Galaxy and contained a number of small gas-rich dwarfs comparable to the SMC. This theoretical view is extensively discussed in the framework that considers a connection with the formation history of the Large Magellanic Cloud.

  14. Theoretical Modelling of Magnetic Refrigeration Materials A PhD studentship is available in the Warwick Theory Group on a theoretical/computational PhD project

    E-Print Network [OSTI]

    Low, Robert

    Theoretical Modelling of Magnetic Refrigeration Materials A PhD studentship is available in the Warwick Theory Group on a theoretical/computational PhD project on the modelling of magnetic refrigeration or air, or for very low temperatures, helium. Therefore, magnetic refrigeration is environmentally

  15. Next generation aerosol-cloud microphysics for advanced high-resolution climate predictions

    SciTech Connect (OSTI)

    Bennartz, Ralf; Hamilton, Kevin P; Phillips, Vaughan T.J.; Wang, Yuqing; Brenguier, Jean-Louis

    2013-01-14T23:59:59.000Z

    The three top-level project goals are: -We proposed to develop, test, and run a new, physically based, scale-independent microphysical scheme for those cloud processes that most strongly affect greenhouse gas scenarios, i.e. warm cloud microphysics. In particular, we propsed to address cloud droplet activation, autoconversion, and accretion. -The new, unified scheme was proposed to be derived and tested using the University of Hawaii's IPRC Regional Atmospheric Model (iRAM). -The impact of the new parameterizations on climate change scenarios will be studied. In particular, the sensitivity of cloud response to climate forcing from increased greenhouse gas concentrations will be assessed.

  16. Mixed phase clouds, cloud electrification and remote sensing.

    SciTech Connect (OSTI)

    Chylek, P. (Petr); Borel, C. C. (Christoph C.); Klett, James

    2004-01-01T23:59:59.000Z

    Most of hypothesis trying to explain charge separation in thunderstorm clouds require presence of ice and supercooled water. Thus the existence of ice or at least mixed phase regions near cloud tops should be a necessary (but not a sufficient) condition for development of lightning. We show that multispectral satellite based instruments, like the DOE MTI (Multispectral Thermal Imager) or NASA MODIS (Moderate Resolution Imaging Spectroradiometer), using the near infrared and visible spectral bands are able to distinguish between water, ice and mixed phase cloud regions. An analysis of the MTI images of mixed phase clouds - with spatial resolution of about 20 m - shows regions of pure water, pure ice as well as regions of water/ice mixtures. We suggest that multispectral satellite instruments may be useful for a short time forecast of lightning probabilities.

  17. A complex network approach to cloud computing

    E-Print Network [OSTI]

    Travieso, Gonzalo; Bruno, Odemir Martinez; Costa, Luciano da Fontoura

    2015-01-01T23:59:59.000Z

    Cloud computing has become an important means to speed up computing. One problem influencing heavily the performance of such systems is the choice of nodes as servers responsible for executing the users' tasks. In this article we report how complex networks can be used to model such a problem. More specifically, we investigate the performance of the processing respectively to cloud systems underlain by Erdos-Renyi and Barabasi-Albert topology containing two servers. Cloud networks involving two communities not necessarily of the same size are also considered in our analysis. The performance of each configuration is quantified in terms of two indices: the cost of communication between the user and the nearest server, and the balance of the distribution of tasks between the two servers. Regarding the latter index, the ER topology provides better performance than the BA case for smaller average degrees and opposite behavior for larger average degrees. With respect to the cost, smaller values are found in the BA ...

  18. Outflow Driven Turbulence in Molecular Clouds

    E-Print Network [OSTI]

    Jonathan J. Carroll; Adam Frank; Eric G. Blackman; Andrew J. Cunningham; Alice C. Quillen

    2008-05-30T23:59:59.000Z

    In this paper we explore the relationship between protostellar outflows and turbulence in molecular clouds. Using 3-D numerical simulations we focus on the hydrodynamics of multiple outflows interacting within a parsec scale volume. We explore the extent to which transient outflows injecting directed energy and momentum into a sub-volume of a molecular cloud can be converted into random turbulent motions. We show that turbulence can readily be sustained by these interactions and show that it is possible to broadly characterize an effective driving scale of the outflows. We compare the velocity spectrum obtained in our studies to that of isotropically forced hydrodynamic turbulence finding that in outflow driven turbulence a power law is indeed achieved. However we find a steeper spectrum (beta ~ 3) is obtained in outflow driven turbulence models than in isotropically forced simulations (beta ~ 2). We discuss possible physical mechanisms responsible for these results as well and their implications for turbulence in molecular clouds where outflows will act in concert with other processes such as gravitational collapse.

  19. Cloud structure and composition of Jupiter's troposphere from 5-{\\mu}m Cassini VIMS spectroscopy

    E-Print Network [OSTI]

    Giles, Rohini S; Irwin, Patrick G J

    2015-01-01T23:59:59.000Z

    Jupiter's tropospheric composition and cloud structure are studied using Cassini VIMS 4.5-5.1 {\\mu}m thermal emission spectra from the 2000-2001 flyby. We make use of both nadir and limb darkening observations on the planet's nightside, and compare these with dayside observations. Although there is significant spatial variability in the 5-{\\mu}m brightness temperatures, the shape of the spectra remain very similar across the planet, suggesting the presence of a spectrally-flat, spatially inhomogeneous cloud deck. We find that a simple cloud model consisting of a single, compact cloud is able to reproduce both nightside and dayside spectra, subject to the following constraints: (i) the cloud base is located at pressures of 1.2 bar or lower; (ii) the cloud particles are highly scattering; (iii) the cloud is sufficiently spectrally flat. Using this cloud model, we search for global variability in the cloud opacity and the phosphine deep volume mixing ratio. We find that the vast majority of the 5-{\\mu}m inhomoge...

  20. A novel approach for introducing cloud spatial structure into cloud radiative transfer parameterizations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Dong; Liu, Yangang

    2014-12-01T23:59:59.000Z

    Subgrid-scale variability is one of the main reasons why parameterizations are needed in large-scale models. Although some parameterizations started to address the issue of subgrid variability by introducing a subgrid probability distribution function for relevant quantities, the spatial structure has been typically ignored and thus the subgrid-scale interactions cannot be accounted for physically. Here we present a new statistical-physics-like approach whereby the spatial autocorrelation function can be used to physically capture the net effects of subgrid cloud interaction with radiation. The new approach is able to faithfully reproduce the Monte Carlo 3D simulation results with several orders less computational cost,more »allowing for more realistic representation of cloud radiation interactions in large-scale models.« less

  1. A novel approach for introducing cloud spatial structure into cloud radiative transfer parameterizations

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, Dong [Brookhaven National Laboratory (BNL), Upton, NY (United States); Liu, Yangang [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2014-12-01T23:59:59.000Z

    Subgrid-scale variability is one of the main reasons why parameterizations are needed in large-scale models. Although some parameterizations started to address the issue of subgrid variability by introducing a subgrid probability distribution function for relevant quantities, the spatial structure has been typically ignored and thus the subgrid-scale interactions cannot be accounted for physically. Here we present a new statistical-physics-like approach whereby the spatial autocorrelation function can be used to physically capture the net effects of subgrid cloud interaction with radiation. The new approach is able to faithfully reproduce the Monte Carlo 3D simulation results with several orders less computational cost, allowing for more realistic representation of cloud radiation interactions in large-scale models.

  2. Global circulation as the main source of cloud activity on Titan

    E-Print Network [OSTI]

    Rodriguez, Sébastien; Rannou, Pascal; Tobie, Gabriel; Baines, Kevin H; Barnes, Jason W; Griffith, Caitlin A; Hirtzig, Mathieu; Pitman, Karly M; Sotin, Christophe; Brown, Robert H; Buratti, Bonnie J; Clark, Roger N; Nicholson, Phil D; 10.1038/NATURE08014

    2009-01-01T23:59:59.000Z

    Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole, resulting from the subsidence and condensation of ethane-rich air into the colder troposphere. General circulation models predict that this distribution should change with the seasons on a 15-year timescale, and that clouds should develop under certain circumstances at temperate latitudes (~40\\degree) in the winter hemisphere. The models, however, have hitherto been poorly constrained and their long-term predictions have not yet been observationally verified. Here we report that the global spatial cloud coverage on Titan is in general agreement with the models, confirming that cloud activity is mainly controlled by the global circ...

  3. Impossibility of secure cloud quantum computing for classical client

    E-Print Network [OSTI]

    Tomoyuki Morimae; Takeshi Koshiba

    2014-07-07T23:59:59.000Z

    The first generation quantum computer will be implemented in the cloud style, since only few groups will be able to access such an expensive and high-maintenance machine. How the privacy of the client can be protected in such a cloud quantum computing? It was theoretically shown [A. Broadbent, J. F. Fitzsimons, and E. Kashefi, Proceedings of the 50th Annual IEEE Symposium on Foundation of Computer Science, 517 (2009)], and experimentally demonstrated [S. Barz, E. Kashefi, A. Broadbent, J. F. Fitzsimons, A. Zeilinger, and P. Walther, Science {\\bf335}, 303 (2012)] that a client who can generate randomly-rotated single qubit states can delegate her quantum computing to a remote quantum server without leaking any privacy. The generation of a single qubit state is not too much burden for the client, and therefore we can say that "almost classical client" can enjoy the secure cloud quantum computing. However, isn't is possible to realize a secure cloud quantum computing for a client who is completely free from any quantum technology? Here we show that perfectly-secure cloud quantum computing is impossible for a completely classical client unless classical computing can simulate quantum computing, or a breakthrough is brought in classical cryptography.

  4. Aerosol-cloud radiative effects from passive satellite instruments Mar%n de Graaf

    E-Print Network [OSTI]

    Graaf, Martin de

    Graaf Global annual mean Earth's energy budget for March 2000 ­ May 2004 (Wm2) [Trenberth et al. 2009 Satellite measurements of absorbing aerosols Reflectance Difference Method Cloud modelling Results Outlook] Global energy budget #12;Absorbing Aerosol Workshop, 15 October2013, Leipzig Aerosol effects over clouds

  5. Author's personal copy Estimates of radiation over clouds and dust aerosols

    E-Print Network [OSTI]

    Baum, Bryan A.

    and clouds are computed for the community radiative transfer model (CRTM) that is a flagship effort, and for ultimately improving the assessment of the Earth's radiant energy budget. Clouds and aerosols are usually field measured by satellite sensors Contents lists available at ScienceDirect journal homepage: www

  6. BUILDING ROOF SEGMENTATION AND RECONSTRUCTION FROM LIDAR POINT CLOUDS USING CLUSTERING TECHNIQUES

    E-Print Network [OSTI]

    Shan, Jie

    BUILDING ROOF SEGMENTATION AND RECONSTRUCTION FROM LIDAR POINT CLOUDS USING CLUSTERING TECHNIQUES presents an approach to creating a polyhedral model of building roof from LiDAR point clouds using. The normal vectors are then clustered together to determine the principal directions of the roof planes

  7. GROUND-BASED CLOUD IMAGES AND SKY RADIANCES IN THE VISIBLE AND NEAR INFRARED REGION FROM

    E-Print Network [OSTI]

    Shields, Janet

    the atmospheric heating rates as well as the amount of solar radiation including biologically effective UV preliminary comparisons with model calculations and cloud cover data both from another type of sky imager data are of specific importance to study the role of clouds on the radiation balance of the earth

  8. Inconsistencies between satellite estimates of longwave cloud forcing and dynamical fields from reanalyses

    E-Print Network [OSTI]

    Allan, Richard P.

    of cloud cover. We argue that monthly mean clear-sky outgoing longwave radiation (OLRc) measurements] The greenhouse effect of cloud may be quantified as the difference between outgoing longwave radiation (OLR longwave radiative effect is made which is directly comparable with standard climate model diagnostics

  9. Gamma-Ray Emission From Crushed Clouds in Supernova Remnants

    SciTech Connect (OSTI)

    Uchiyama, Yasunobu; Blandford, Roger D.; Funk, Stefan; /SLAC; Tajima, Hiroyasu; /Nagoya U., Solar-Terrestrial Environ. Lab.; Tanaka, Takaaki; /KIPAC, Menlo Park; ,

    2010-10-27T23:59:59.000Z

    It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of {pi}{sup 0}-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.

  10. Cloud Computing and Validation of Expandable In Silico Livers

    E-Print Network [OSTI]

    Ropella, Glen EP; Hunt, C Anthony

    2010-01-01T23:59:59.000Z

    benefit analysis of cloud computing versus desktop grids.as: Ropella and Hunt: Cloud computing and validation ofCloud computing and validation of expandable in silico

  11. Cloud Occurrence Frequency at the Barrow, Alaska, ARM Climate Research Facility for 2008 Third Quarter 2009 ARM and Climate Change Prediction Program Metric Report

    SciTech Connect (OSTI)

    M Jensen; K Johnson; JH Mather

    2009-07-14T23:59:59.000Z

    Clouds represent a critical component of the Earth’s atmospheric energy balance as a result of their interactions with solar and terrestrial radiation and a redistribution of heat through convective processes and latent heating. Despite their importance, clouds and the processes that control their development, evolution and lifecycle remain poorly understood. Consequently, the simulation of clouds and their associated feedbacks is a primary source of inter-model differences in equilibrium climate sensitivity. An important step in improving the representation of cloud process simulations is an improved high-resolution observational data set of the cloud systems including their time evolution. The first order quantity needed to understand the important role of clouds is the height of cloud occurrence and how it changes as a function of time. To this end, the Atmospheric Radiation Measurement (ARM) Climate Research Facilities (ACRF) suite of instrumentation has been developed to make the observations required to improve the representation of cloud systems in atmospheric models.

  12. Title: Networking the Cloud: Enabling Enterprise Computing and Storage Cloud computing has been changing how enterprises run and manage their IT systems. Cloud

    E-Print Network [OSTI]

    Title: Networking the Cloud: Enabling Enterprise Computing and Storage Abstract: Cloud computing has been changing how enterprises run and manage their IT systems. Cloud computing platforms provide introduction on Cloud Computing. We propose a Virtual Cloud Pool abstraction to logically unify cloud

  13. Arctic Mixed-Phase Cloud Properties Derived from Surface-Based Sensors at SHEBA MATTHEW D. SHUPE AND SERGEY Y. MATROSOV

    E-Print Network [OSTI]

    Shupe, Matthew

    , cloud-top liquid layer from which ice particles formed and fell, although deep, multilayered mixed-phase. These values are all larger than those found in single-phase ice clouds at SHEBA. Vertically resolved cloud phases can coexist is in question. A re- view of model parameterizations shows the lower tem- perature

  14. Evolution of non-uniformly seeded warm clouds in idealized turbulent conditions This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Falkovich, Gregory

    clouds containing only the liquid phase, which are one of the most important in their effect on radiation to condensation and collisions and droplet loss due to fallout. The model accounts for the effects of cloud forcing by anthropogenic aerosols is their effect on clouds, referred to as the aerosol indirect effect [1

  15. The Temperature of Interstellar Clouds from Turbulent Heating

    E-Print Network [OSTI]

    Liubin Pan; Paolo Padoan

    2008-10-22T23:59:59.000Z

    To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the dimension of the most dissipative structures. By comparing the model with the probability distribution of the turbulent dissipation rate in a simulation of supersonic and super-Alfvenic turbulence, we find a best-fit value of d=1.64. We apply this intermittency model to the computation of the mass-weighted probability distribution of the gas temperature of molecular clouds, high-mass star-forming cores, and cold diffuse HI clouds. Our main results are: i) The mean gas temperature in molecular clouds can be explained as the effect of turbulent heating alone, while cosmic ray heating may dominate only in regions where the turbulent heating is low; ii) The mean gas temperature in high-mass star-forming cores with typical FWHM of ~6 km/s (corresponding to a 1D rms velocity of 2.5 km/s) may be completely controlled by turbulent heating, which predicts a mean value of approximately 36 K, two to three times larger than the mean gas temperature in the absence of turbulent heating; iii) The intermittency of the turbulent heating can generate enough hot regions in cold diffuse HI clouds to explain the observed CH+ abundance, if the rms velocity on a scale of 1 pc is at least 3 km/s, in agreement with previous results based on incompressible turbulence. Because of its importance in the thermal balance of molecular clouds and high-mass star-forming cores, the process of turbulent heating may be central in setting the characteristic stellar mass and in regulating molecular chemical reactions.

  16. Cluster analysis of cloud properties : a method for diagnosing cloud-climate feedbacks

    E-Print Network [OSTI]

    Gordon, Neil D.

    2008-01-01T23:59:59.000Z

    represent cloud effects on gridbox mean visible radiationclouds and the resulting effect on the balance of radiationrepresent cloud effects on grid-box-mean visible radiation

  17. Phenomenological implications of the nucleon's meson cloud

    E-Print Network [OSTI]

    T. J. Hobbs

    2015-05-29T23:59:59.000Z

    The long-distance structure of the interacting nucleon receives important contributions from its couplings to light hadronic degrees of freedom -- a light meson cloud -- while an analogous nonperturbative mechanism is expected to generate an intrinsic charm (IC) component to the proton wavefunction. We investigate both possibilities, keeping for the former a special eye to improving the theoretical understanding of the pion-nucleon vertex in light of proposed measurements. Regarding the latter possibility of IC, we highlight recent results obtained by a global QCD analysis of the light-front model proposed in Hobbs et al. (Phys Rev D 89:074008, 2014).

  18. Genetic refinement of cloud-masking algorithms for the multi-spectral thermal imager (MTI)

    SciTech Connect (OSTI)

    Hirsch, K. L. (Karen L.); Davis, A. B. (Anthony B.); Harvey, N. R. (Neal R.); Rohde, C. A. (Charles A.); Brumby, Steven P.

    2001-01-01T23:59:59.000Z

    The Multi-spectral Thermal Imager (MTI) is a high-performance remote-sensing satellite designed, owned and operated by the U.S. Department of Energy, with a dual mission in environmental studies and in nonproliferation. It has enhanced spatial and radiometric resolutions and state-of-the-art calibration capabilities. This instrumental development puts a new burden on retrieval algorithm developers to pass this accuracy on to the inferred geophysical parameters. In particular, the atmospheric correction scheme assumes the intervening atmosphere will be modeled as a plane-parallel horizontally-homogeneous medium. A single dense-enough cloud in view of the ground target can easily offset reality from the calculations, hence the need for a reliable cloud-masking algorithm. Pixel-scale cloud detection relies on the simple facts that clouds are generally whiter, brighter, and colder than the ground below; spatially, dense clouds are generally large on some scale. This is a good basis for searching multispectral datacubes for cloud signatures. However, the resulting cloud mask can be very sensitive to the choice of thresholds in whiteness, brightness, temperature, and connectivity. We have used a genetic algorithm trained on (MODIS Airborne Simulator-based) simulated MTI data to design a cloud-mask. Its performance is compared quantitatively to hand-drawn training data and to the EOS/Terra MODIS cloud mask.

  19. Tropical Warm Pool International Cloud Experiment (TWP-ICE): Cloud and Rain Characteristics in the Australian Monsoon

    SciTech Connect (OSTI)

    PT May; C Jakob; JH Mather

    2004-05-30T23:59:59.000Z

    The impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool – International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them. The experiment is a collaboration between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program, the Bureau of Meteorology (BoM), the National Aeronautics and Space Administration (NASA), the European Commission DG RTD-1.2, and several United States, Australian, Canadian, and European Universities. This experiment will be undertaken over a 4-week period in early 2006. January and February corresponds to the wet phase of the Australia monsoon. This season has been selected because, despite Darwin’s coastal location, the convection that occurs over and near Darwin at this time is largely of maritime origin with a large fetch over water. Based on previous experiments, the convection appears typical of maritime convection with widespread convection that has complex organization, but is not as deep or as intense as continental or coastal convection. Therefore, it is expected that the convection and cloud characteristics will be representative of conditions typical for wide areas of the tropics.

  20. Tropical and Subtropical Cloud Transitions in Weather and Climate Prediction Models: The GCSS/WGNE Pacific Cross-Section Intercomparison (GPCI)

    E-Print Network [OSTI]

    Randall, David A.

    , Paris, France e Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia, Canada f, Melbourne, Victoria, Australia i Monash University, Melbourne, Victoria, Australia j Department of Earth for the season June­July­August

  1. Studies of 3D-cloud optical depth from small to very large values, and of the radiation and remote sensing impacts of larger-drop clustering

    SciTech Connect (OSTI)

    None

    2007-05-04T23:59:59.000Z

    We have basically completed all the goals stated in the previous proposal and published or submitted journal papers thereon, the only exception being First-Principles Monte Carlo which has taken more time than expected. We finally finished the comprehensive book on 3D cloud radiative transfer (edited by Marshak and Davis and published by Springer), with many contributions by ARM scientists; this book was highlighted in the 2005 ARM Annual Report. We have also completed (for now) our pioneering work on new models of cloud drop clustering based on ARM aircraft FSSP data, with applications both to radiative transfer and to rainfall. This clustering work was highlighted in the FY07 “Our Changing Planet” (annual report of the US Climate Change Science Program). Our group published 22 papers, one book, and 5 chapters in that book, during this proposal period. All are listed at the end of this section. Below, we give brief highlights of some of those papers.

  2. Dust takes detour on ice-cloud journey | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dust takes detour on ice-cloud journey Dust takes detour on ice-cloud journey Pollution-coated particles bypass ice formation, but influence clouds Cirrus clouds are composed of...

  3. Group X

    SciTech Connect (OSTI)

    Fields, Susannah

    2007-08-16T23:59:59.000Z

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  4. The Dynamical Structure and Evolution of Giant Molecular Clouds

    E-Print Network [OSTI]

    Christopher F. McKee

    1999-01-26T23:59:59.000Z

    Giant molecular clouds (GMCs) are the sites of star formation in the Galaxy. Many of their properties can be understood in terms of a model in which the GMCs and the star-forming clumps within them are in approximate pressure equilibrium, with turbulent motions treated as a separate pressure component.

  5. Monday, March 13, 2006 MARS: CORE TO CLOUDS

    E-Print Network [OSTI]

    Rathbun, Julie A.

    with current orbital configurations. We run the model for five years with a northern water ice cap then release Core [#1500] We present new melting data in the system Fe-Ni-S at Martian core pressures, using multi. Clouds, Cap, and Consequences: Outflow Events and Mars Hesperian Climate [#1484] We focus on how outflows

  6. Pricing of Service in Clouds: Optimal Response and Strategic Interactions

    E-Print Network [OSTI]

    Urgaonkar, Bhuvan

    . INTRODUCTION Cloud providers and consumers encounter a variety of pric- ing models devised to disincentivize.g., a data center procuring power from an electric utility based on tiered [10] or peak-based [5] pricing (we and paying the data center rather than an electric utility for provisioned power [9]). Ta- ble 1 presents

  7. Compact High Velocity Clouds

    E-Print Network [OSTI]

    Robert Braun

    2000-09-01T23:59:59.000Z

    We summarize the observed properties of the CHVC population, which provide strong evidence for source distances in the range 200-1000 kpc. At these distances, the population corresponds to strongly dark-matter dominated sub-dwarf galaxies still accreting onto the more massive Local Group systems. Recent searches for faint associated stellar populations have revealed red-giant candidates for which follow-up spectroscopy is scheduled. A sensitive HI survey for CHVC counterparts in the NGC 628 galaxy group has allowed tentative detection of 40 candidates, for which confirming observations have been approved. Many open issues should be resolved by observational programs within the coming years.

  8. 3D cloud detection and tracking system for solar forecast using multiple sky imagers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Peng, Zhenzhou; Yu, Dantong; Huang, Dong; Heiser, John; Yoo, Shinjae; Kalb, Paul

    2015-08-01T23:59:59.000Z

    We propose a system for forecasting short-term solar irradiance based on multiple total sky imagers (TSIs). The system utilizes a novel method of identifying and tracking clouds in three-dimensional space and an innovative pipeline for forecasting surface solar irradiance based on the image features of clouds. First, we develop a supervised classifier to detect clouds at the pixel level and output cloud mask. In the next step, we design intelligent algorithms to estimate the block-wise base height and motion of each cloud layer based on images from multiple TSIs. This information is then applied to stitch images together into largermore »views, which are then used for solar forecasting. We examine the system’s ability to track clouds under various cloud conditions and investigate different irradiance forecast models at various sites. We confirm that this system can 1) robustly detect clouds and track layers, and 2) extract the significant global and local features for obtaining stable irradiance forecasts with short forecast horizons from the obtained images. Finally, we vet our forecasting system at the 32-megawatt Long Island Solar Farm (LISF). Compared with the persistent model, our system achieves at least a 26% improvement for all irradiance forecasts between one and fifteen minutes.« less

  9. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    ScienceCinema (OSTI)

    Norris, Joe [Scripps Institution of Oceanography, University of California, San Diego, California, USA

    2010-09-01T23:59:59.000Z

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  10. Cloud Feedbacks on Climate: A Challenging Scientific Problem

    SciTech Connect (OSTI)

    Norris, Joel (Scripps Institution of Oceanography, UC San Diego) [Scripps Institution of Oceanography, UC San Diego

    2010-05-10T23:59:59.000Z

    One reason it has been difficult to develop suitable social and economic policies to address global climate change is that projected global warming during the coming century has a large uncertainty range. The primary physical cause of this large uncertainty range is lack of understanding of the magnitude and even sign of cloud feedbacks on the climate system. If Earth's cloudiness responded to global warming by reflecting more solar radiation back to space or allowing more terrestrial radiation to be emitted to space, this would mitigate the warming produced by increased anthropogenic greenhouse gases. Contrastingly, a cloud response that reduced solar reflection or terrestrial emission would exacerbate anthropogenic greenhouse warming. It is likely that a mixture of responses will occur depending on cloud type and meteorological regime, and at present, we do not know what the net effect will be. This presentation will explain why cloud feedbacks have been a challenging scientific problem from the perspective of theory, modeling, and observations. Recent research results on observed multidecadal cloud-atmosphere-ocean variability over the Pacific Ocean will also be shown, along with suggestions for future research.

  11. Simulating Electron Clouds in Heavy-Ion Accelerators

    SciTech Connect (OSTI)

    Cohen, R.H.; Friedman, A.; Kireeff Covo, M.; Lund, S.M.; Molvik,A.W.; Bieniosek, F.M.; Seidl, P.A.; Vay, J-L.; Stoltz, P.; Veitzer, S.

    2005-04-07T23:59:59.000Z

    Contaminating clouds of electrons are a concern for most accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly-, weakly-, and un-magnetized. They describe their approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. They present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at Lawrence Berkeley National Laboratory, in which the machine can be flooded with electrons released by impact of the ion beam and an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrates the ability of the large-timestep mover to accurately calculate the instability.

  12. Socially Optimal Pricing of Cloud Computing Resources

    E-Print Network [OSTI]

    Menache, Ishai

    The cloud computing paradigm offers easily accessible computing resources of variable size and capabilities. We consider a cloud-computing facility that provides simultaneous service to a heterogeneous, time-varying ...

  13. AN INVESTIGATION ON THE MORPHOLOGICAL EVOLUTION OF BRIGHT-RIMMED CLOUDS

    SciTech Connect (OSTI)

    Miao Jingqi [Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NR (United Kingdom); White, Glenn J. [Centre for Earth, Planetary, Space and Astronomical Research, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Thompson, M. A. [School of Physics Astronomy and Maths, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Nelson, Richard P. [School of Mathematical Sciences, Queen Mary College, University of London, Mile End Road, London E1 4NS (United Kingdom)], E-mail: J.Miao@kent.ac.uk

    2009-02-10T23:59:59.000Z

    A new radiative driven implosion (RDI) model based on smoothed particle hydrodynamics technique is developed and applied to investigate the morphological evolutions of molecular clouds under the effect of ionizing radiation. This model self-consistently includes the self-gravity of the cloud in the hydrodynamical evolution, the UV radiation component in the radiation transferring equations, the relevant heating and cooling mechanisms in the energy evolution, and a comprehensive chemical network. The simulation results reveal that under the effect of ionizing radiation, a molecular cloud may evolve through different evolutionary sequences. Depending on its initial gravitational state, the evolution of a molecular cloud does not necessarily follow a complete morphological evolution sequence from type A{yields}B{yields}C, as described by previous RDI models. When confronted with observations, the simulation results provide satisfactory physical explanations for a series of puzzles derived from bright-rimmed clouds observations. The consistency of the modeling results with observations shows that the self-gravity of a molecular cloud should not be neglected in any investigation on the dynamical evolution of molecular clouds when they are exposed to ionizing radiation.

  14. An Investigation on the Morphological Evolution of Bright-Rimmed Clouds

    E-Print Network [OSTI]

    J. Miao; G. J. White; M. A. Thompson; R. P. Nelson

    2008-10-15T23:59:59.000Z

    A new Radiative Driven Implosion (RDI) model based on Smoothed Particle Hydrodynamics (SPH) technique is developed and applied to investigate the morphological evolutions of molecular clouds under the effect of ionising radiation. This model self-consistently includes the self-gravity of the cloud in the hydrodynamical evolution, the UV radiation component in the radiation transfer equations, the relevant heating and cooling mechanisms in the energy evolution and a comprehensive chemical network. The simulation results reveal that under the effect of ionising radiation, a molecular cloud may evolve through different evolutionary sequences. Dependent on its initial gravitational state, the evolution of a molecular cloud does not necessarily follow a complete morphological evolution sequence from type A to B to C, as described by previous RDI models. When confronted with observations, the simulation results provide satisfactory physical explanations for a series of puzzles derived from Bright-Rimmed Clouds (BRCs) observations. The consistency of the modelling results with observations shows that the self-gravity of a molecular cloud should not be neglected in any investigation on the dynamical evolution of molecular clouds when they are exposed to ionising radiation.

  15. SCANNING CLOUD RADAR OBSERVATIONS AT AZORES: PRELIMINARY 3D CLOUD PRODUCTS

    E-Print Network [OSTI]

    SCANNING CLOUD RADAR OBSERVATIONS AT AZORES: PRELIMINARY 3D CLOUD PRODUCTS P. Kollias, I. Jo, A, NY www.bnl.gov ABSTRACT The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers

  16. Cloud-Top Temperatures for Precipitating Winter Clouds JAY W. HANNA

    E-Print Network [OSTI]

    Schultz, David

    1 Cloud-Top Temperatures for Precipitating Winter Clouds JAY W. HANNA NOAA/NESDIS Satellite of satellite-derived cloud-top brightness temperatures from GOES longwave infrared (channel 4) satellite data, rain, freezing rain, and sleet. The distributions of cloud-top brightness temperatures were constructed

  17. Cloud networking and communications Cloud computing is having an important impact on

    E-Print Network [OSTI]

    Boutaba, Raouf

    Editorial Cloud networking and communications Cloud computing is having an important impact attention has been devoted to system aspects of Cloud computing. More recently, however, the focus is shifting towards Cloud net- working and communications with evolutionary and revo- lutionary propositions

  18. Cloud seeding as a technique for studying aerosol-cloud interactions in marine stratocumulus

    E-Print Network [OSTI]

    Miami, University of

    Cloud seeding as a technique for studying aerosol-cloud interactions in marine stratocumulus hygroscopic aerosols were introduced into a solid marine stratocumulus cloud (200 m thick) by burning hygroscopic flares mounted on an aircraft. The cloud microphysical response in two parallel seeding plumes

  19. The Cloud Adoption Toolkit: Supporting Cloud Adoption Decisions in the Enterprise

    E-Print Network [OSTI]

    Sommerville, Ian

    1 The Cloud Adoption Toolkit: Supporting Cloud Adoption Decisions in the Enterprise Ali Khajeh-Hosseini, David Greenwood, James W. Smith, Ian Sommerville Cloud Computing Co-laboratory, School of Computer Science University of St Andrews, UK {akh, dsg22, jws7, ifs}@cs.st-andrews.ac.uk Abstract Cloud computing

  20. CLOUD COMPUTING AND INFORMATION POLICY 1 Cloud Computing and Information Policy

    E-Print Network [OSTI]

    Lin, Jimmy

    CLOUD COMPUTING AND INFORMATION POLICY 1 Cloud Computing and Information Policy: Computing in a Policy Cloud? Forthcoming in the Journal of Information Technology and Politics, 5(3). Paul T. Jaeger University of Maryland Jimmy Lin University of Maryland Justin M. Grimes University of Maryland #12;CLOUD

  1. HPI Cloud Symposium ,Operating The Cloud` 25.09.2013, Hasso-Plattner-Institut, Auditorium Building

    E-Print Network [OSTI]

    Weske, Mathias

    Agenda HPI Cloud Symposium ,Operating The Cloud` 25.09.2013, Hasso-Plattner-Institut, Auditorium Building 09:30h Registration 10:00h Opening Prof. Dr. Christoph Meinel, HPI Potsdam 10:30h Cloud-RAID: Eine Methode zur Bereitstellung zuverlässiger Speicherressourcen in Öffentlichen Clouds Maxim Schnajkin, HPI

  2. Cloud Verifier: Verifiable Auditing Service for IaaS Clouds Joshua Schiffman

    E-Print Network [OSTI]

    Jaeger, Trent

    Cloud Verifier: Verifiable Auditing Service for IaaS Clouds Joshua Schiffman Security Architecture University Park, PA, USA yus138,hvijay,tjaeger@cse.psu.edu Abstract--Cloud computing has commoditized compute paradigm, its adoption has been stymied by cloud platform's lack of trans- parency, which leaves customers

  3. From mini-clouds to Cloud Computing Boris Mejias, Peter Van Roy

    E-Print Network [OSTI]

    Bonaventure, Olivier

    From mini-clouds to Cloud Computing Boris Mej´ias, Peter Van Roy Universit´e catholique de Louvain ­ Belgium {boris.mejias|peter.vanroy}@uclouvain.be Abstract Cloud computing has many definitions with different views within industry and academia, but everybody agrees on that cloud computing is the way

  4. AnonymousCloud: A Data Ownership Privacy Provider Framework in Cloud Computing

    E-Print Network [OSTI]

    Hamlen, Kevin W.

    AnonymousCloud: A Data Ownership Privacy Provider Framework in Cloud Computing Safwan Mahmud Khan their computation results are ultimately delivered. To provide this data ownership privacy, the cloud's distributed-anonymity; authentication; cloud computing; in- formation security; privacy; Tor I. INTRODUCTION Revolutionary advances

  5. Leveraging Platform Basic Services in Cloud Application Platforms for the Development of Cloud

    E-Print Network [OSTI]

    Simons, Anthony J. H.

    Leveraging Platform Basic Services in Cloud Application Platforms for the Development of Cloud.Simons@dcs.shef.ac.uk Abstract-- Cloud application platforms gain popularity and have the potential to alter the way service based cloud applications are developed involving utilisation of platform basic services. A platform

  6. Development and testing of an aerosol/stratus cloud parameterization scheme for middle and high latitudes. Final technical progress report, November 1, 1994--October 31, 1998

    SciTech Connect (OSTI)

    Kreidenweis, S.M.; Cotton, W.R.

    1999-05-20T23:59:59.000Z

    At the present time, general circulation models (GCMs) poorly represent clouds, to the extent that they cannot be relied upon to simulate the climatic effects of increasing concentrations of greenhouse gases, or of anthropogenic perturbations to concentrations of cloud condensation nuclei (CCN) or ice nuclei (IN). The long-term objective of this research was the development of an aerosol/cloud microphysics parameterization of mixed-phase stratus and boundary-layer clouds which responds to variations in CCN and IN. The work plan was to perform simulations of these cloud systems to gain understanding of their dynamics and microphysics, especially how aerosols affect cloud development and properties, that cold then be used to guide parameterizations. Several versions of the CSU RAMS (Regional Atmospheric Modeling System), modified to treat Arctic clouds, have been used during the course of this work. The authors also developed a new modeling system, the Trajectory Ensemble Model, to perform detailed chemical and microphysical simulations off-line from the host LES model. The increased understanding of the cloud systems investigated in this research can be applied to a single-column cloud model, designed as an adaptive grid model which can interface into a GCM vertical grid through distinct layers of the troposphere where the presence of layer clouds is expected.

  7. Carbon Chemistry in interstellar clouds

    E-Print Network [OSTI]

    Maryvonne Gerin; David Fosse; Evelyne Roueff

    2002-12-03T23:59:59.000Z

    We discuss new developments of interstellar chemistry, with particular emphasis on the carbon chemistry. We confirm that carbon chains and cycles are ubiquitous in the ISM and closely chemically related to ea ch other, and to carbon. Investigation of the carbon budget in shielded and UV illuminated gas shows that the inventory of interstellar molecules is not complete and more complex molecules with 4 or more carbon atoms must be present. Finally we discuss the consequences for the evolution of clouds and conclude that the ubiquitous presence of carbon chains and cycles is not a necessary consequence of a very young age for interstellar clouds.

  8. Changes in high cloud conditions

    E-Print Network [OSTI]

    Himebrook, Richard Frank

    1974-01-01T23:59:59.000Z

    ). When the effect of unknowns is added to the data (Figs. 3(a) and 3(b), p, 21), the period with most high-cloud cover seems to alter- nate back and forth almost monthly, The average, global, solar radiation (Fig. 3(c), p. 21) depicts a decrease from... radiation, per cent possible sunshine, and average sky cover. The increases in high-cloud cover occurred in areas with the following characteristics: strong upper-air flow; frequent jet ' aircraft traffic; coverage of less than half the sky; late...

  9. Use of airs and modis thermal infrared channels to retrieve ice cloud properties

    E-Print Network [OSTI]

    Yost, Christopher Rogers

    2007-04-25T23:59:59.000Z

    In this study, we use thermal infrared channels to retrieve the optical thickness and effective particle radius of ice clouds. A physical model is used in conjunction with Atmospheric Infrared Sounder (AIRS) temperature and water vapor profiles...

  10. Use of airs and modis thermal infrared channels to retrieve ice cloud properties 

    E-Print Network [OSTI]

    Yost, Christopher Rogers

    2007-04-25T23:59:59.000Z

    In this study, we use thermal infrared channels to retrieve the optical thickness and effective particle radius of ice clouds. A physical model is used in conjunction with Atmospheric Infrared Sounder (AIRS) temperature and water vapor profiles...

  11. THE SMITH CLOUD: HIGH-VELOCITY ACCRETION AND DARK MATTER CONFINEMENT

    SciTech Connect (OSTI)

    Nichols, M.; Bland-Hawthorn, J., E-mail: m.nichols@physics.usyd.edu.a [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

    2009-12-20T23:59:59.000Z

    The Smith Cloud is a massive system of metal-poor neutral and ionized gas (M{sub gas} approx> 2 x 10{sup 6} M{sub sun}) that is presently moving at high velocity (V{sub GSR}approx 300 km s{sup -1}) with respect to the Galaxy at a distance of 12 kpc from the Sun. The kinematics of the cloud's cometary tail indicates that the gas is in the process of accretion onto the Galaxy, as first discussed by Lockman et al. Here, we re-investigate the cloud's orbit by considering the possibility that the cloud is confined by a dark matter halo. This is required for the cloud to survive its passage through the Galactic corona. We consider three possible models for the dark matter halo (Navarro-Frenk-White (NFW), Einasto, and Burkert) including the effects of tidal disruption and ram pressure stripping during the cloud's infall onto and passage through the Galactic disk. For the NFW and Einasto dark matter models, we are able to determine reasonable initial conditions for the Smith Cloud, although this is only marginally possible with the Burkert model. For all three models, the progenitor had an initial (gas+dark matter) mass that was an order-of-magnitude higher than inferred today. In agreement with Lockman et al., the cloud appears to have punched through the disk approx70 Myr ago. For our most successful models, the baryon-to-dark matter ratio is fairly constant during an orbital period but drops by a factor of 2-5 after transiting the disk. The cloud appears to have only marginally survived its transit and is unlikely to retain its integrity during the next transit approx 30 Myr from now.

  12. Microsoft Private Cloud Title of document

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Microsoft Private Cloud Title of document 1 1 Microsoft Private Cloud A Comparative Look at Functionality, Benefits, and Economics November2012 #12;Microsoft Private Cloud Title of document 2 2 Copyright Information © 2012 Microsoft Corporation. All rights reserved. This document is provided "as-is." Information

  13. Performance Engineering for Cloud Computing John Murphy

    E-Print Network [OSTI]

    Murphy, John

    Performance Engineering for Cloud Computing John Murphy Lero ­ The Irish Software Engineering.Murphy@ucd.ie Abstract. Cloud computing potentially solves some of the major challenges in the engineering of large efficient operation. This paper argues that cloud computing is an area where performance engineering must

  14. Level Set Implementations on Unstructured Point Cloud

    E-Print Network [OSTI]

    Duncan, James S.

    Level Set Implementations on Unstructured Point Cloud by HO, Hon Pong A Thesis Submitted;Level Set Implementations on Unstructured Point Cloud by HO, Hon Pong This is to certify that I have implementations on unstructured point cloud 15 3.1 Level set initialization

  15. Cloud Security: Issues and Concerns Pierangela Samarati*

    E-Print Network [OSTI]

    Samarati, Pierangela

    1 Cloud Security: Issues and Concerns Authors Pierangela Samarati* Universitŕ degli Studi di Milano, Italy sabrina.decapitani@unimi.it Keywords cloud security confidentiality integrity availability secure data storage and processing Summary The cloud has emerged as a successful computing paradigm

  16. Cloud Computing: Centralization and Data Sovereignty

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Cloud Computing: Centralization and Data Sovereignty Primavera De Filippi, Smari McCarthy Abstract: Cloud computing can be defined as the provision of computing resources on-demand over and elasticity of costs, problems arise concerning the collection of personal information in the Cloud

  17. Optimizing Offloading Strategies in Mobile Cloud Computing

    E-Print Network [OSTI]

    Hyytiä, Esa

    Optimizing Offloading Strategies in Mobile Cloud Computing Esa Hyyti¨a Department of Communications Abstract--We consider a dynamic offloading problem arising in the context of mobile cloud computing (MCC consider the task assignment problem arising in the context of the mobile cloud computing (MCC). In MCC

  18. CONTROLLING DATA IN THE CLOUD: OUTSOURCING COMPUTATION

    E-Print Network [OSTI]

    Zou, Cliff C.

    #12;CONTROLLING DATA IN THE CLOUD: OUTSOURCING COMPUTATION WITHOUT OUTSOURCING CONTROL Paper By Laboratories Of America 2009 ACM WORKSHOP ON CLOUD COMPUTING SECURITY (CCSW 2009) Presented By Talal Basaif CAP that will arise later · New directions to solve some issues #12;INTRODUCTION · Cloud computing is one of desirable

  19. Towards a Ubiquitous Cloud Computing Infrastructure

    E-Print Network [OSTI]

    van der Merwe, Kobus

    Towards a Ubiquitous Cloud Computing Infrastructure Jacobus Van der Merwe, K.K. Ramakrishnan of a number of cloud computing use cases. We specifically consider cloudbursting and follow-the-sun and focus that are also network service providers. I. INTRODUCTION Cloud computing is rapidly gaining acceptance

  20. Cloud Computing: Legal Issues in Centralized Architectures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Cloud Computing: Legal Issues in Centralized Architectures Primavera DE FILIPPI1 , Smari McCARTHY2, Reykjavik, 101, Iceland - Email: smari@gmail.com Abstract: Cloud computing can be defined as the provision they can access their data and the extent to which parties can exploit it. Keywords: Cloud Computing

  1. The Radiative Role of Free Tropospheric Aerosols and Marine Clouds over the Central North Atlantic

    SciTech Connect (OSTI)

    Mazzoleni, Claudio [Michigan Technological University; Kumar, Sumit [Michigan Technological University; Wright, Kendra [Michigan Technological University; Kramer, Louisa [Michigan Technological University; Mazzoleni, Lynn [Michigan Technological University; Owen, Robert [Michigan Technological University; Helmig, Detlev [University of Colorado at Boulder

    2014-12-09T23:59:59.000Z

    The scientific scope of the project was to exploit the unique location of the Pico Mountain Observatory (PMO) located in the summit caldera of the Pico Volcano in Pico Island in the Azores, for atmospheric studies. The observatory, located at 2225m a.s.l., typically samples free tropospheric aerosols laying above the marine low-level clouds and long-range transported from North America. The broad purpose of this research was to provide the scientific community with a better understanding of fundamental physical processes governing the effects of aerosols on radiative forcing and climate; with the ultimate goal of improving our abilities to understand past climate and to predict future changes through numerical models. The project was 'exploratory' in nature, with the plan to demonstrate the feasibility of deploying for the first time, an extensive aerosol research package at PMO. One of the primary activities was to test the deployment of these instruments at the site, to collect data during the 2012 summer season, and to further develop the infrastructure and the knowledge for performing novel research at PMO in follow-up longer-term aerosol-cloud studies. In the future, PMO could provide an elevated research outpost to support the renewed DOE effort in the Azores that was intensified in 2013 with the opening of the new sea-level ARM-DOE Eastern North Atlantic permanent facility at Graciosa Island. During the project period, extensive new data sets were collected for the planned 2012 season. Thanks to other synergistic activities and opportunities, data collection was then successfully extended to 2013 and 2014. Highlights of the scientific findings during this project include: a) biomass burning contribute significantly to the aerosol loading in the North Atlantic free troposphere; however, long-range transported black carbon concentrations decreased substantially in the last decade. b) Single black carbon particles – analyzed off-line at the electron microscope – were often very compacted, suggesting cloud processing and exhibiting different optical properties from fresh emissions. In addition, black carbon was found to be sometimes mixed with mineral dust, affecting its optical properties and potential forcing. c) Some aerosols collected at PMO acted as ice nuclei, potentially contributing to cirrus cloud formation during their transport in the upper free troposphere. Identified good ice nuclei were often mineral dust particles. d) The free tropospheric aerosols studied at PMO have relevance to low level marine clouds due, for example, to synoptic subsidence entraining free tropospheric aerosols into the marine boundary layer. This has potentially large consequences on cloud condensation nuclei concentrations and compositions in the marine boundary layer; therefore, having an effect on the marine stratus clouds, with potentially important repercussions on the radiative forcing. The scientific products of this project currently include contributions to two papers published in the Nature Publishing group (Nature Communications and Scientific Reports), one paper under revision for Atmospheric Chemistry and Physics, one in review in Geophysical Research Letters and one recently submitted to Atmospheric Chemistry and Physics Discussion. In addition, four manuscripts are in advanced state of preparation. Finally, twenty-eight presentations were given at international conferences, workshops and seminars.

  2. How might a statistical cloud scheme be coupled to a mass-flux convection scheme?

    SciTech Connect (OSTI)

    Klein, Stephen A.; Pincus, Robert; Hannay, Cecile; Xu, Kuan-man

    2004-09-27T23:59:59.000Z

    The coupling of statistical cloud schemes with mass-flux convection schemes is addressed. Source terms representing the impact of convection are derived within the framework of prognostic equations for the width and asymmetry of the probability distribution function of total water mixing ratio. The accuracy of these source terms is quantified by examining output from a cloud resolving model simulation of deep convection. Practical suggestions for inclusion of these source terms in large-scale models are offered.

  3. Geosci. Model Dev., 6, 12751298, 2013 www.geosci-model-dev.net/6/1275/2013/

    E-Print Network [OSTI]

    Boyer, Edmond

    for the 3-D cloud-resolving mesoscale model Meso-NH with application to idealized cases M. Leriche, J-dimensional cloud resolv- ing mesoscale model. This module includes gaseous- and aqueous-phase chemical reactions

  4. What Goes Up Must Come Down: The Lifecycle of Convective Clouds (492nd Brookhaven Lecture)

    SciTech Connect (OSTI)

    Jensen, Michael [BNL Environmental Sciences

    2014-02-19T23:59:59.000Z

    Some clouds look like cotton balls and others like anvils. Some bring rain, some snow and sleet, and others, just shade. But, whether big and billowy or dark and stormy, clouds affect far more than the weather each day. Armed with measurements of clouds’ updrafts and downdrafts—which resemble airflow in a convection oven—and many other atmospheric interactions, scientists from Brookhaven Lab and other institutions around the world are developing models that are crucial for understanding Earth’s climate and forecasting future climate change. During his lecture, Dr. Jensen provides an overview of the importance of clouds in the Earth’s climate system before explaining how convective clouds form, grow, and dissipate. His discussion includes findings from the Midlatitude Continental Convective Clouds Experiment (MC3E), a major collaborative experiment between U.S. Department of Energy (DOE) and NASA scientists to document precipitation, clouds, winds, and moisture in 3-D for a holistic view of convective clouds and their environment.

  5. Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud II: A Parameter Study

    E-Print Network [OSTI]

    Takahiro Kudoh; Shantanu Basu

    2006-01-04T23:59:59.000Z

    We use numerical simulations to study the effect of nonlinear MHD waves in a stratified, self-gravitating molecular cloud that is bounded by a hot and tenuous external medium. In a previous paper, we had shown the details of a standard model and studied the effect of varying the dimensionless amplitude. In this paper, we present the results of varying two other important free parameters: beta_0, the initial ratio of gas to magnetic pressure at the cloud midplane, and the dimensionless frequency of driving. Furthermore, we present the case of a temporally random driving force. Our results demonstrate that a very important consideration for the actual level of turbulent support against gravity is the ratio of driving wavelength lambda_0 to the the size of the initial non-turbulent cloud; maximum cloud expansion is achieved when this ratio is close to unity. The best consistency with the observational correlation of magnetic field strength, turbulent line width, and density is achieved by cloud models with beta_0 approx 1. We also calculate the spatial power spectra of the turbulent clouds, and show that significant power is developed on scales larger than the scale length H_0 of the initial cloud, even if the input wavelength of turbulence lambda_0 approx H_0. The cloud stratification and resulting increase of Alfven speed toward the cloud edge allows for a transfer of energy to wavelengths significantly larger than lambda_0. This explains why the relevant time scale for turbulent dissipation is the crossing time over the cloud scale rather than the crossing time over the driving scale.

  6. Cloud Seeding By: Julie Walter

    E-Print Network [OSTI]

    Toohey, Darin W.

    , smoke, that then are cooled because of the high altitudes. As the water or condensation nuclei cool more pushed up enough the warm air that is filled with moisture should reach an optimum cooling point-based Western Weather Consultants, whose company supplied Vail Resorts with the cloud seeding generators

  7. Cloud and Autonomic Computing Center

    E-Print Network [OSTI]

    Gelfond, Michael

    boundary layers and wind turbine aerodynamics Siva Parameswarn, Ph.D. Professor in the Department vehicles » Wake development behind wind turbines PHYSICS Ismael Regis de Farias Jr., Ph.D. Associate in cloud environments » Intelligent data management & understanding » Automated web service composition

  8. Using Surface Remote Sensors to Derive Radiative Characteristics of Mixed-Phase Clouds: An Example from M-PACE

    SciTech Connect (OSTI)

    de Boer, Gijs; Collins, William D.; Menon, Surabi; Long, Charles N.

    2011-12-02T23:59:59.000Z

    Measurements from ground-based cloud radar, high spectral resolution lidar and microwave radiometer are used in conjunction with a column version of the Rapid Radiative Transfer Model (RRTMG) and radiosonde measurements to derive the surface radiative properties under mixed-phase cloud conditions. These clouds were observed during the United States Department of Energy (US DOE) Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment (M-PACE) between September and November of 2004. In total, sixteen half hour time periods are reviewed due to their coincidence with radiosonde launches. Cloud liquid (ice) water paths are found to range between 11.0-366.4 (0.5-114.1) gm-2, and cloud physical thicknesses fall between 286-2075 m. Combined with temperature and hydrometeor size estimates, this information is used to calculate surface radiative flux densities using RRTMG, which are demonstrated to generally agree with measured flux densities from surface-based radiometric instrumentation. Errors in longwave flux density estimates are found to be largest for thin clouds, while shortwave flux density errors are generally largest for thicker clouds. A sensitivity study is performed to understand the impact of retrieval assumptions and uncertainties on derived surface radiation estimates. Cloud radiative forcing is calculated for all profiles, illustrating longwave dominance during this time of year, with net cloud forcing generally between 50 and 90 Wm-2.

  9. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

    SciTech Connect (OSTI)

    Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying

    2015-01-01T23:59:59.000Z

    A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they will be included in a future public release of WRF-Chem.

  10. A Comparison of Multiscale Variations of Decade-long Cloud Fractions from Six Different Platforms over the Southern Great Plains in the United States

    SciTech Connect (OSTI)

    Wu, Wei; Liu, Yangang; Jensen, Michael; Toto, Tami; Foster, Michael J.; Long, Charles N.

    2014-03-27T23:59:59.000Z

    This study investigates 1997-2011 observationally based cloud fraction estimates from different platforms over the Southern Great Plains, United States, including three ground-based estimates and three satellite-based estimates at multiple temporal and spatial scales. They are: 1) the Active Remotely Sensed Clouds Locations (ARSCL); 2) the Total Sky Imager (TSI); 3) the Radiative Flux Analysis (RFA); 4) Geostationary Operational Environmental Satellite (GOES); 5) the International Satellite Cloud Climatology Project (ISCCP); and 6) Advanced Very High Resolution Radiometer Pathfinder Atmospheres Extended (PATMOS-x). A substantial disagreement is evident among different estimates, especially for ISCCP and ARSCL with statistically significant larger cloud fractions than the other estimates. For example, ISCCP and ARSCL mean cloud fractions in January are ~21% and 8% larger than the average from all the other estimates, respectively. Three estimates (ISCCP, ARSCL, GOES) exhibit an 8%-10% overall increase in the annually averaged cloud fractions from 1998 to 2009; the other three estimates (TSI, RFA, and PATMOS-x) exhibit no significant tendency of increase in this decade. Monthly cloud fractions from all the estimates exhibit Gaussian-like distributions while the distributions of daily cloud fractions are dependent on spatial scales. Investigations of high-resolution cloud fractions reveal that the differences stem from the inconsistent definitions of cloud fraction. Findings from this study suggest caution when using observationally based cloud fraction estimates for climate studies, highlighting that the consistency in defining cloud fraction between models and observations is crucial for studying the Earth’s climate.

  11. Refinement, Validation and Application of Cloud-Radiation Parameterization in a GCM

    SciTech Connect (OSTI)

    Dr. Graeme L. Stephens

    2009-04-30T23:59:59.000Z

    The research performed under this award was conducted along 3 related fronts: (1) Refinement and assessment of parameterizations of sub-grid scale radiative transport in GCMs. (2) Diagnostic studies that use ARM observations of clouds and convection in an effort to understand the effects of moist convection on its environment, including how convection influences clouds and radiation. This aspect focuses on developing and testing methodologies designed to use ARM data more effectively for use in atmospheric models, both at the cloud resolving model scale and the global climate model scale. (3) Use (1) and (2) in combination with both models and observations of varying complexity to study key radiation feedback Our work toward these objectives thus involved three corresponding efforts. First, novel diagnostic techniques were developed and applied to ARM observations to understand and characterize the effects of moist convection on the dynamical and thermodynamical environment in which it occurs. Second, an in house GCM radiative transfer algorithm (BUGSrad) was employed along with an optimal estimation cloud retrieval algorithm to evaluate the ability to reproduce cloudy-sky radiative flux observations. Assessments using a range of GCMs with various moist convective parameterizations to evaluate the fidelity with which the parameterizations reproduce key observable features of the environment were also started in the final year of this award. The third study area involved the study of cloud radiation feedbacks and we examined these in both cloud resolving and global climate models.

  12. The Role of Gravity Waves in the Formation and Organization of Clouds during TWPICE

    SciTech Connect (OSTI)

    Reeder, Michael J. [Monash University; Lane, Todd P. [University of Melbourne; Hankinson, Mai Chi Nguyen [Monash University

    2013-09-27T23:59:59.000Z

    All convective clouds emit gravity waves. While it is certain that convectively-generated waves play important parts in determining the climate, their precise roles remain uncertain and their effects are not (generally) represented in climate models. The work described here focuses mostly on observations and modeling of convectively-generated gravity waves, using the intensive observations from the DoE-sponsored Tropical Warm Pool International Cloud Experiment (TWP-ICE), which took place in Darwin, from 17 January to 13 February 2006. Among other things, the research has implications the part played by convectively-generated gravity waves in the formation of cirrus, in the initiation and organization of further convection, and in the subgrid-scale momentum transport and associated large-scale stresses imposed on the troposphere and stratosphere. The analysis shows two groups of inertia-gravity waves are detected: group L in the middle stratosphere during the suppressed monsoon period, and group S in the lower stratosphere during the monsoon break period. Waves belonging to group L propagate to the south-east with a mean intrinsic period of 35 h, and have vertical and horizontal wavelengths of about 5-6 km and 3000-6000 km, respectively. Ray tracing calculations indicate that these waves originate from a deep convective region near Indonesia. Waves belonging to group S propagate to the south-south-east with an intrinsic period, vertical wavelength and horizontal wavelength of about 45 h, 2 km and 2000-4000 km, respectively. These waves are shown to be associated with shallow convection in the oceanic area within about 1000 km of Darwin. The intrinsic periods of high-frequency waves are estimated to be between 20-40 minutes. The high-frequency wave activity in the stratosphere, defined by mass-weighted variance of the vertical motion of the sonde, has a maximum following the afternoon local convection indicating that these waves are generated by local convection. The wave activity is strongest in the lower stratosphere below 22 km and, during the suppressed monsoon period, is modulated with a 3-4-day period. The concentration of the wave activity in the lower stratosphere is consistent with the properties of the environment in which these waves propagate, whereas its 3-4-day modulation is explained by the variation of the convection activity in the TWP-ICE domain. At low rainfall intensity the wave activity increases as rainfall intensity increases. At high values of rainfall intensity, however, the wave activity associated with deep convective clouds is independent of the rainfall intensity. The convection and gravity waves observed during TWP-ICE are simulated with the Weather Research and Forecasting (WRF) Model. These simulations are compared with radiosonde observations described above and are used to determine some of the properties of convectively generated gravity waves. The gravity waves appear to be well simulated by the model. The model is used to explore the relationships between the convection, the gravity waves and cirrus.

  13. Presentations by the Nizkorodov group members -1 Presentations by the Nizkorodov Group Students and Postdoctoral Researchers

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    the group his/her name is shown in green · If the presenting author is a postdoctoral researcher fromUCI International Workshop, January 2014, Laguna Beach, California, USA H.J. Lee, P. Aiona, A. Laskin, J. Laskin, S dissolved in cloud and fog waters 41. 2012 AirUCI International Workshop, January 2012, Laguna Beach

  14. Oval BA (and the Great Red Spot) extend down to a supersolar water cloud layer in Jupiter's atmosphere

    E-Print Network [OSTI]

    Marcus, Philip S.

    Oval BA (and the Great Red Spot) extend down to a supersolar water cloud layer in Jupiter in Jupiter's troposphere, with stable layers near cloud bases [4,6,7]. We use these two results to determine horizontal band in Fig. 2 shows that vortex- model derived static stability (white bars) is consistent

  15. Simulating mixed-phase Arctic stratus clouds: Sensitivity to ice initiationmechanisms

    SciTech Connect (OSTI)

    Sednev, I.; Menon, S.; McFarquhar, G.

    2009-04-10T23:59:59.000Z

    The importance of Arctic mixed-phase clouds on radiation and the Arctic climate is well known. However, the development of mixed-phase cloud parameterization for use in large scale models is limited by lack of both related observations and numerical studies using multidimensional models with advanced microphysics that provide the basis for understanding the relative importance of different microphysical processes that take place in mixed-phase clouds. To improve the representation of mixed-phase cloud processes in the GISS GCM we use the GISS single-column model coupled to a bin resolved microphysics (BRM) scheme that was specially designed to simulate mixed-phase clouds and aerosol-cloud interactions. Using this model with the microphysical measurements obtained from the DOE ARM Mixed-Phase Arctic Cloud Experiment (MPACE) campaign in October 2004 at the North Slope of Alaska, we investigate the effect of ice initiation processes and Bergeron-Findeisen process (BFP) on glaciation time and longevity of single-layer stratiform mixed-phase clouds. We focus on observations taken during October 9th-10th, which indicated the presence of a single-layer mixed-phase clouds. We performed several sets of 12-hour simulations to examine model sensitivity to different ice initiation mechanisms and evaluate model output (hydrometeors concentrations, contents, effective radii, precipitation fluxes, and radar reflectivity) against measurements from the MPACE Intensive Observing Period. Overall, the model qualitatively simulates ice crystal concentration and hydrometeors content, but it fails to predict quantitatively the effective radii of ice particles and their vertical profiles. In particular, the ice effective radii are overestimated by at least 50%. However, using the same definition as used for observations, the effective radii simulated and that observed were more comparable. We find that for the single-layer stratiform mixed-phase clouds simulated, process of ice phase initiation due to freezing of supercooled water in both saturated and subsaturated (w.r.t. water) environments is as important as primary ice crystal origination from water vapor. We also find that the BFP is a process mainly responsible for the rates of glaciation of simulated clouds. These glaciation rates cannot be adequately represented by a water-ice saturation adjustment scheme that only depends on temperature and liquid and solid hydrometeors contents as is widely used in bulk microphysics schemes and are better represented by processes that also account for supersaturation changes as the hydrometeors grow.

  16. Simulating mixed-phase Arctic stratus clouds: sensitivity to ice initiation mechanisms

    SciTech Connect (OSTI)

    Sednev, Igor; Sednev, I.; Menon, S.; McFarquhar, G.

    2008-02-18T23:59:59.000Z

    The importance of Arctic mixed-phase clouds on radiation and the Arctic climate is well known. However, the development of mixed-phase cloud parameterization for use in large scale models is limited by lack of both related observations and numerical studies using multidimensional models with advanced microphysics that provide the basis for understanding the relative importance of different microphysical processes that take place in mixed-phase clouds. To improve the representation of mixed-phase cloud processes in the GISS GCM we use the GISS single-column model coupled to a bin resolved microphysics (BRM) scheme that was specially designed to simulate mixed-phase clouds and aerosol-cloud interactions. Using this model with the microphysical measurements obtained from the DOE ARM Mixed-Phase Arctic Cloud Experiment (MPACE) campaign in October 2004 at the North Slope of Alaska, we investigate the effect of ice initiation processes and Bergeron-Findeisen process (BFP) on glaciation time and longevity of single-layer stratiform mixed-phase clouds. We focus on observations taken during 9th-10th October, which indicated the presence of a single-layer mixed-phase clouds. We performed several sets of 12-h simulations to examine model sensitivity to different ice initiation mechanisms and evaluate model output (hydrometeors concentrations, contents, effective radii, precipitation fluxes, and radar reflectivity) against measurements from the MPACE Intensive Observing Period. Overall, the model qualitatively simulates ice crystal concentration and hydrometeors content, but it fails to predict quantitatively the effective radii of ice particles and their vertical profiles. In particular, the ice effective radii are overestimated by at least 50%. However, using the same definition as used for observations, the effective radii simulated and that observed were more comparable. We find that for the single-layer stratiform mixed-phase clouds simulated, process of ice phase initiation due to freezing of supercooled water in both saturated and undersaturated (w.r.t. water) environments is as important as primary ice crystal origination from water vapor. We also find that the BFP is a process mainly responsible for the rates of glaciation of simulated clouds. These glaciation rates cannot be adequately represented by a water-ice saturation adjustment scheme that only depends on temperature and liquid and solid hydrometeors contents as is widely used in bulk microphysics schemes and are better represented by processes that also account for supersaturation changes as the hydrometeors grow.

  17. 8, 601686, 2008 Modelling Cirrus

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ), but the global effect is still uncertain. The formation and evolution of cirrus clouds depends in a complex way). Cirrus clouds modulate the Earth's radiation budget signifi- cantly. It is assumed that (thin) cirrusACPD 8, 601­686, 2008 Modelling Cirrus Clouds ­ Part 1 P. Spichtinger and K. Gierens Title Page

  18. UNDERSTANDING TRENDS ASSOCIATED WITH CLOUDS IN IRRADIATED EXOPLANETS

    SciTech Connect (OSTI)

    Heng, Kevin [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Demory, Brice-Olivier, E-mail: kevin.heng@csh.unibe.ch, E-mail: demory@mit.edu [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2013-11-10T23:59:59.000Z

    Unlike previously explored relationships between the properties of hot Jovian atmospheres, the geometric albedo and the incident stellar flux do not exhibit a clear correlation, as revealed by our re-analysis of Q0-Q14 Kepler data. If the albedo is primarily associated with the presence of clouds in these irradiated atmospheres, a holistic modeling approach needs to relate the following properties: the strength of stellar irradiation (and hence the strength and depth of atmospheric circulation), the geometric albedo (which controls both the fraction of starlight absorbed and the pressure level at which it is predominantly absorbed), and the properties of the embedded cloud particles (which determine the albedo). The anticipated diversity in cloud properties renders any correlation between the geometric albedo and the stellar flux weak and characterized by considerable scatter. In the limit of vertically uniform populations of scatterers and absorbers, we use an analytical model and scaling relations to relate the temperature-pressure profile of an irradiated atmosphere and the photon deposition layer and to estimate whether a cloud particle will be lofted by atmospheric circulation. We derive an analytical formula for computing the albedo spectrum in terms of the cloud properties, which we compare to the measured albedo spectrum of HD 189733b by Evans et al. Furthermore, we show that whether an optical phase curve is flat or sinusoidal depends on whether the particles are small or large as defined by the Knudsen number. This may be an explanation for why Kepler-7b exhibits evidence for the longitudinal variation in abundance of condensates, while Kepler-12b shows no evidence for the presence of condensates despite the incident stellar flux being similar for both exoplanets. We include an 'observer's cookbook' for deciphering various scenarios associated with the optical phase curve, the peak offset of the infrared phase curve, and the geometric albedo.

  19. Adler, R. F., H.-Y. M. Yeh, N. Prasad, W.-K. Tao, and J. Simpson, 1991: Microwave simulations of a tropical rainfall system with a three-dimensional cloud model. J.

    E-Print Network [OSTI]

    Jiang, Haiyan

    : Vertical motion characteristics of tropical cyclones determined with airborne Doppler radial velocity. J­953. Amayenc, P., M. Marzoug, and J. Testud, 1993: Analysis of crossbeam resolution effects in rainfall rate, 1999: On the effect of the melting layer on microwave emission of clouds over the ocean. J. Atmos. Sci

  20. Why do Particle Clouds Generate Electric Charges?

    E-Print Network [OSTI]

    T. Pähtz; H. J. Herrmann; T. Shinbrot

    2015-03-16T23:59:59.000Z

    Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cause devastating explosions in food, drug and coal processing industries. Despite the wide-ranging importance of granular charging in both nature and industry, even the simplest aspects of its causes remain elusive, because it is difficult to understand how inert grains in contact with little more than other inert grains can generate the large charges observed. Here, we present a simple yet predictive explanation for the charging of granular materials in collisional flows. We argue from very basic considerations that charge transfer can be expected in collisions of identical dielectric grains in the presence of an electric field, and we confirm the model's predictions using discrete-element simulations and a tabletop granular experiment.

  1. Geometric Algorithms for Modeling, Motion, and Animation (GAMMA): Collision Detection Videos from the University of North Carolina GAMMA Research Group

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Physically based modeling simulations depend highly on the physical interaction between objects in a scene. Complex physics engines require fast, accurate, and robust proximity queries to maintain a realistic simulation at interactive rates. We couple our proximity query research with physically based modeling to ensure that our packages provide the capabilities of today's physics engines.[Copied from http://www.cs.unc.edu/~geom/collide/index.shtml

  2. While much of the effort to combat climate change impacts addresses the roles of the cryosphere, forests and Earth's oceans, less is known about the role of clouds. Prof Dr Pier Siebesma of the Royal

    E-Print Network [OSTI]

    Haak, Hein

    climate models to represent cloud processes and their effect on the radiative energy balance. The premise Watching the skies Could you explain the workings of cloud feedback and the effect climate change has had that clouds reflect up to 70 per cent of the incoming solar radiation whereas the sea's surface only reflects

  3. Formation and Collapse of Nonaxisymmetric Protostellar Cores in Planar Magnetic Molecular Clouds

    E-Print Network [OSTI]

    Shantanu Basu; Glenn E. Ciolek

    2004-03-31T23:59:59.000Z

    We extend our earlier work on ambipolar diffusion induced formation of protostellar cores in isothermal sheet-like magnetic interstellar clouds, by studying nonaxisymmetric collapse for the physically interesting regime of magnetically critical and supercritical model clouds ($\\mui \\geq 1$, where $\\mui$ is the initial mass-to-magnetic flux ratio in units of the critical value for gravitational collapse). Cores that form in model simulations are effectively triaxial, with shapes that are typically closer to being oblate, rather than prolate. Infall velocities in the critical model ($\\mui = 1$) are subsonic; in contrast, a supercritical model ($\\mui = 2$) has extended supersonic infall that may be excluded by observations. For the magnetically critical model, ambipolar diffusion forms cores that are supercritical ($\\muc > 1$) and embedded within subcritical envelopes ($\\muenv < 1$). Cores in our models have density profiles that eventually merge into a near-uniform background, which is suggestive of observed properties of cloud cores.

  4. Group Analysis Jean Daunizeau

    E-Print Network [OSTI]

    Daunizeau, Jean

    ) is measurement error True response magnitude is fixed 111 Xy Fixed effect #12;Random effects-sphericity modelling Examples Power and efficiency: summary Overview #12;Group analysis: fixed versus random effects Two RFX methods: Holmes & Friston (HF) approach non-sphericity modelling Examples Power

  5. Aneka: A Software Platform for .NET-based Cloud Computing

    E-Print Network [OSTI]

    Vecchiola, Christian; Buyya, Rajkumar

    2009-01-01T23:59:59.000Z

    Aneka is a platform for deploying Clouds developing applications on top of it. It provides a runtime environment and a set of APIs that allow developers to build .NET applications that leverage their computation on either public or private clouds. One of the key features of Aneka is the ability of supporting multiple programming models that are ways of expressing the execution logic of applications by using specific abstractions. This is accomplished by creating a customizable and extensible service oriented runtime environment represented by a collection of software containers connected together. By leveraging on these architecture advanced services including resource reservation, persistence, storage management, security, and performance monitoring have been implemented. On top of this infrastructure different programming models can be plugged to provide support for different scenarios as demonstrated by the engineering, life science, and industry applications.

  6. Analysis of cloud layer structure in Shouxian, China using RS92 radiosonde aided by 95 GHz cloud radar

    E-Print Network [OSTI]

    Li, Zhanqing

    Analysis of cloud layer structure in Shouxian, China using RS92 radiosonde aided by 95 GHz cloud to analyze cloud vertical structure over this area by taking advantage of the first direct measurements of cloud vertical layers from the 95 GHz radar. Singlelayer, twolayer, and threelayer clouds account for 28

  7. In Proceedings of APSEC 2010 Cloud Workshop, Sydney, Australia, 30th An Analysis of The Cloud Computing Security Problem

    E-Print Network [OSTI]

    Grundy, John

    of The Cloud Computing Security Problem Mohamed Al Morsy, John Grundy and Ingo Müller Computer Science to adopt IT without upfront investment. Despite the potential gains achieved from the cloud computing solution. Keywords: cloud computing; cloud computing security; cloud computing security management. I

  8. April 12, 2014: The Era of Cloud Computing is coming Headline: The Era of Cloud Computing is coming

    E-Print Network [OSTI]

    Buyya, Rajkumar

    April 12, 2014: The Era of Cloud Computing is coming #12;Headline: The Era of Cloud Computing of Cloud Computing at a seminar in MANIT and RGPV on Saturday. Inset headline: This is the right time to build a career in Cloud Computing Article: Prof. Rajkumar Buyya gave guidance to students about Cloud

  9. After the definition of Cloud Computing ... What has NIST done in the Cloud space lately? What's next?

    E-Print Network [OSTI]

    After the definition of Cloud Computing ... What has NIST done in the Cloud space lately? What Publication SP 500-292: Cloud Computing Reference Architecture. This document takes the NIST definition of Cloud Computing a step further by expanding the definition into a logical representation of the cloud

  10. Generated using version 3.0 of the official AMS LATEX template Computing and Partitioning Cloud Feedbacks using Cloud1

    E-Print Network [OSTI]

    Hartmann, Dennis

    by adjusting the change in cloud radiative forcing for non-cloud22 related effects as in Soden et al. (2008 planet, the global and annual mean effect40 of clouds at the top of atmosphere (TOA) is to increase Feedbacks using Cloud1 Property Histograms.2 Part I: Cloud Radiative Kernels3 Mark D. Zelinka Department

  11. Influence of Cloud-Top Height and Geometric Thickness on a MODIS Infrared-Based Ice Cloud Retrieval

    E-Print Network [OSTI]

    Baum, Bryan A.

    of the net cloud radiative forc- ing of these clouds requires a global, diurnal climatology, which can most and temporal scales. In this study, the sensitivity of an infrared-based ice cloud retrieval to effective cloud temperature is investigated, with a focus on the effects of cloud-top height and geometric thickness

  12. Statistical representation of clouds in climate models

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary900 SpecialNanoparticulateEmissions Targetson6

  13. CLOUD MODELING CHALLENGES FOR CLIMATE CHANGE SIMULATION

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C o . C l a r k CCLEAN ENERGY JOBS AND

  14. The LANL Cloud-Aerosol Model

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in the Earth's Lower Mantle Print It is nowThe K-25The

  15. CHARACTERIZATION OF CLOUDS IN TITAN'S TROPICAL ATMOSPHERE

    SciTech Connect (OSTI)

    Griffith, Caitlin A.; Penteado, Paulo [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85719 (United States); Rodriguez, Sebastien [Laboratoire AIM, Universite Paris 7/CNRS/CEA-Saclay, DSM/IRFU/SAp (France); Le Mouelic, Stephane [Laboratoire de Planetologie et Geodynamique, CNRS, UMR-6112, Universite de Nantes, 44000 Nantes (France); Baines, Kevin H.; Buratti, Bonnie; Sotin, Christophe [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Clark, Roger [U.S. Geological Survey, Denver, CO 80225 (United States); Nicholson, Phil [Department of Astronomy, Cornell University, Ithaca, NY (United States); Jaumann, Ralf [Institute of Planetary Exploration, Deutsche Zentrum, fuer Luft- und Raumfahrt (Germany)

    2009-09-10T23:59:59.000Z

    Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere. Radiative transfer analyses indicate similarities between summer polar and tropical methane clouds. Like their southern counterparts, tropical clouds consist of particles exceeding 5 {mu}m. They display discrete structures suggestive of convective cumuli. They prevail at a specific latitude band between 8 deg. - 20 deg. S, indicative of a circulation origin and the beginning of a circulation turnover. Yet, unlike the high latitude clouds that often reach 45 km altitude, these discrete tropical clouds, so far, remain capped to altitudes below 26 km. Such low convective clouds are consistent with the highly stable atmospheric conditions measured at the Huygens landing site. Their characteristics suggest that Titan's tropical atmosphere has a dry climate unlike the south polar atmosphere, and despite the numerous washes that carve the tropical landscape.

  16. Group Interaction Prompted by a Simple Assessed Open Learner Model that can be Optionally Released to Peers

    E-Print Network [OSTI]

    Bull, Susan

    to which these findings may be transferable to other settings. 1 Introduction Open learner models (OLM introduces OLMlets, a simple OLM to help users identify their learning needs. Based on UMPTEEN [4], OLMlets of OLMs. The aim in this paper is to provide an indication of what can be achieved with a simple OLM

  17. Dark Clouds on the Horizon: Using Cloud Storage as Attack Vector and Online Slack Space

    E-Print Network [OSTI]

    Dark Clouds on the Horizon: Using Cloud Storage as Attack Vector and Online Slack Space Martin this as online slack space. We conclude by discussing security improvements for mod- ern online storage services protocol. With the advent of cloud computing and the shared usage of resources, these centralized storage

  18. To Cloud or Not to Cloud: A Mobile Device Perspective on Energy Consumption of Applications

    E-Print Network [OSTI]

    Namboodiri, Vinod

    To Cloud or Not to Cloud: A Mobile Device Perspective on Energy Consumption of Applications Vinod important criteria might be the energy consumed by the applications they run. The goal of this work is to characterize under what scenarios cloud-based applications would be relatively more energy-efficient for users

  19. Aircraft Microphysical Documentation from Cloud Base to Anvils of Hailstorm Feeder Clouds in Argentina

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    in Argentina DANIEL ROSENFELD The Hebrew University of Jerusalem, Jerusalem, Israel WILLIAM L. WOODLEY Woodley, Argentina, with a cloud-physics jet aircraft penetrating the major feeder clouds from cloud base to the 45°C. Introduction The province of Mendoza in western Argentina (32°S, 68°W), which is known worldwide for its wine

  20. Investigating the Radiative Impact Clouds Using Retrieved Properties to Classify Cloud Type

    E-Print Network [OSTI]

    Hogan, Robin

    of Reading, RG6 6AL, UK Abstract. Active remote sensing allows cloud properties such as ice and liquid water remote sensing, Cloud categorization, Cloud properties, Radiative impact. PACS: 92.60. Vb. INTRODUCTION in a radiation scheme which can simulate the radiation budget and heating rates throughout the atmospheric