Sample records for boundary layer clouds

  1. 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

  2. ARM - Field Campaign - Boundary Layer Cloud IOP

    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)8Li (59AJ76)ARM2,govCampaignsAircraftCloud

  3. 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

  4. Shipboard measurements of the cloud-capped marine boundary layer during FIRE/ASTEX

    SciTech Connect (OSTI)

    NONE

    1997-09-01T23:59:59.000Z

    Results are reported on measurements of the cloud-capped marine boundary layer during FIRE/ASTEX. A method was developed from the ASTEX dataset for measuring profiles of liquid water content, droplet size and concentration from cloud radar/microwave radiometer data in marine boundary layer clouds. Profiles were also determined from the first three moments of the Doppler spectrum measured in drizzle with the ETL cloud radar during ASTEX.

  5. Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics

    SciTech Connect (OSTI)

    Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav

    2013-10-01T23:59:59.000Z

    Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.

  6. Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization Schemes in Convection-Permitting Ensemble Forecasts using

    E-Print Network [OSTI]

    Xue, Ming

    uncertainty in how to include various processes (e.g., drop breakup and ice-phase categories 1 Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization In this study, the ability of several cloud microphysical and planetary boundary layer parameterization schemes

  7. 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.

  8. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

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

    Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.

    2015-03-01T23:59:59.000Z

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore »before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less

  9. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

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

    Zhou, Xiaoli [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Kollias, Pavlos [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Lewis, Ernie R. [Brookhaven National Lab., Upton, NY (United States). Biological, Environmental, and Climate Sciences Dept.

    2015-03-01T23:59:59.000Z

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)

  10. 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.

  11. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

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

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al

    2015-05-01T23:59:59.000Z

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmore »for concise representation in models. Values of the aerosol hygroscopicity parameter, ?, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.« less

  12. 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.

  13. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer: Analysis of Results from the ARM Mobile Facility Deployment to the Azores (2009/2010)

    SciTech Connect (OSTI)

    Wood, Robert [University of Washington, Dept of Atmos Sci

    2013-05-31T23:59:59.000Z

    The project focuses upon dataset analysis and synthesis of datasets from the AMF deployment entitled “Clouds, Aerosols, and Precipitation in the Marine Boundary Layer (CAP?MBL)” at Graciosa Island in the Azores. Wood is serving a PI for this AMF deployment.

  14. RACORO LONG-TERM, SYSTEMATIC AIRCRAFT OBSERVATIONS OF BOUNDARY LAYER CLOUDS

    E-Print Network [OSTI]

    ). This type of cloud is common globally, and the Earth's radiative energy balance is particularly sensitive the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid to do so, for United States Government purposes. BNL-91362-2010-CP #12;

  15. 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

  16. METEOROLOGY 130 Boundary Layer Meteorology

    E-Print Network [OSTI]

    Clements, Craig

    4) Turbulence Kinetic Energy · TKE budget and terms · Stability concepts · Richardson number 5) Measuring the Boundary Layer · Balloons · Radars · Sodars · Towers (micrometeorology) · Measuring Turbulence Time Series Analysis 8) Similarity Theory and Turbulence Closure 9) Surface Energy Budgets 10) Special

  17. THE MARTIAN ATMOSPHERIC BOUNDARY LAYER

    E-Print Network [OSTI]

    Spiga, Aymeric

    THE MARTIAN ATMOSPHERIC BOUNDARY LAYER A. Petrosyan,1 B. Galperin,2 S. E. Larsen,3 S. R. Lewis,4 A [Haberle et al., 1993a; Larsen et al., 2002; Hinson et al., 2008]. At night, convection is inhibited

  18. Boundary Layer Cloud Turbulence Characteristics

    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 Materials Find FindRewindParticleBorn on anJeffersonBound

  19. NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds

    E-Print Network [OSTI]

    NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds VINCENT E of boundary layer clouds have used a convenient but idealized longwave radiation formula for clouds in their large-eddy simulations (LESs). Under what conditions is this formula justified? Can it be extended

  20. Improving Subtropical Boundary Layer Cloudiness in the 2011 NCEP GFS

    SciTech Connect (OSTI)

    Fletcher, J. K.; Bretherton, Christopher S.; Xiao, Heng; Sun, Ruiyu N.; Han, J.

    2014-09-23T23:59:59.000Z

    The current operational version of National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) shows significant low cloud bias. These biases also appear in the Coupled Forecast System (CFS), which is developed from the GFS. These low cloud biases degrade seasonal and longer climate forecasts, particularly of short-wave cloud radiative forcing, and affect predicted sea surface temperature. Reducing this bias in the GFS will aid the development of future CFS versions and contributes to NCEP's goal of unified weather and climate modelling. Changes are made to the shallow convection and planetary boundary layer parameterisations to make them more consistent with current knowledge of these processes and to reduce the low cloud bias. These changes are tested in a single-column version of GFS and in global simulations with GFS coupled to a dynamical ocean model. In the single-column model, we focus on changing parameters that set the following: the strength of shallow cumulus lateral entrainment, the conversion of updraught liquid water to precipitation and grid-scale condensate, shallow cumulus cloud top, and the effect of shallow convection in stratocumulus environments. Results show that these changes improve the single-column simulations when compared to large eddy simulations, in particular through decreasing the precipitation efficiency of boundary layer clouds. These changes, combined with a few other model improvements, also reduce boundary layer cloud and albedo biases in global coupled simulations.

  1. Cyclone separator having boundary layer turbulence control

    DOE Patents [OSTI]

    Krishna, Coimbatore R. (Mt. Sinai, NY); Milau, Julius S. (Port Jefferson, NY)

    1985-01-01T23:59:59.000Z

    A cyclone separator including boundary layer turbulence control that is operable to prevent undue build-up of particulate material at selected critical areas on the separator walls, by selectively varying the fluid pressure at those areas to maintain the momentum of the vortex, thereby preventing particulate material from inducing turbulence in the boundary layer of the vortical fluid flow through the separator.

  2. ENTROPY BOUNDARY LAYERS FRANCK SUEUR

    E-Print Network [OSTI]

    Sueur, Franck

    on the boundary. These conditions are used in a reduction of the system. We construct BKW expansions at all order

  3. Energy transport using natural convection boundary layers

    SciTech Connect (OSTI)

    Anderson, R.

    1986-04-01T23:59:59.000Z

    Natural convection is one of the major modes of energy transport in passive solar buildings. There are two primary mechanisms for natural convection heat transport through an aperture between building zones: (1) bulk density differences created by temperature differences between zones; and (2) thermosyphon pumping created by natural convection boundary layers. The primary objective of the present study is to compare the characteristics of bulk density driven and boundary layer driven flow, and discuss some of the advantages associated with the use of natural convection boundary layers to transport energy in solar building applications.

  4. antarctic boundary layer: Topics by E-print Network

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

    Geosciences Websites Summary: Boundary Layer Meteorology (METR 5103) Spring 2014 Syllabus General information Fundamentals of the atmospheric boundary layer dynamics and...

  5. atmosperic boundary layer: Topics by E-print Network

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

    Geosciences Websites Summary: Boundary Layer Meteorology (METR 5103) Spring 2014 Syllabus General information Fundamentals of the atmospheric boundary layer dynamics and...

  6. Numerical Simulation of the Wave Bottom Boundary Layer

    E-Print Network [OSTI]

    Slinn, Donald

    boundary layer. Oscillatory boundary layers are examined using a high-resolution time-dependent threeNumerical Simulation of the Wave Bottom Boundary Layer Over a Smooth Surface. Part 1: Three for turbulent boundary layers that occur over a smooth bottom. Results indicate that turbulence levels

  7. Planetary Boundary Layer from AERI and MPL

    SciTech Connect (OSTI)

    Sawyer, Virginia

    2014-02-13T23:59:59.000Z

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  8. Planetary Boundary Layer from AERI and MPL

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

    Sawyer, Virginia

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  9. Turbulent Fluxes in Stably Stratified Boundary Layers

    E-Print Network [OSTI]

    L'vov, Victor S; Rudenko, Oleksii; 10.1088/0031-8949/2008/T132/014010

    2008-01-01T23:59:59.000Z

    We present an extended version of an invited talk given on the International Conference "Turbulent Mixing and Beyond". The dynamical and statistical description of stably stratified turbulent boundary layers with the important example of the stable atmospheric boundary layer in mind is addressed. Traditional approaches to this problem, based on the profiles of mean quantities, velocity second-order correlations, and dimensional estimates of the turbulent thermal flux run into a well known difficulty, predicting the suppression of turbulence at a small critical value of the Richardson number, in contradiction with observations. Phenomenological attempts to overcome this problem suffer from various theoretical inconsistencies. Here we present an approach taking into full account all the second-order statistics, which allows us to respect the conservation of total mechanical energy. The analysis culminates in an analytic solution of the profiles of all mean quantities and all second-order correlations removing t...

  10. Collaborative Research: ARM observations for the development and evaluation of models and parameterizations of cloudy boundary layers

    SciTech Connect (OSTI)

    Albrecht, Bruce,

    2013-07-12T23:59:59.000Z

    This is a collaborative project with Dr. Ping Zhu at Florida International University. It was designed to address key issues regarding the treatment of boundary layer cloud processes in climate models with UM’s research focusing on the analyses of ARM cloud radar observations from MMCR and WACR and FIU’s research focusing on numerical simulations of boundary layer clouds. This project capitalized on recent advancements in the ARM Millimeter Cloud Radar (MMCR) processing and the development of the WACR (at the SGP) to provide high temporal and spatial resolution Doppler cloud radar measurements for characterizing in-cloud turbulence, large-eddy circulations, and high resolution cloud structures of direct relevance to high resolution numerical modeling studies. The principal focus of the observational component of this collaborative study during this funding period was on stratocumulus clouds over the SGP site and fair-weather cumuli over the Nauru site. The statistical descriptions of the vertical velocity structures in continental stratocumulus clouds and in the Nauru shallow cumuli that are part of this study represents the most comprehensive observations of the vertical velocities in boundary layer clouds to date and were done in collaboration with Drs. Virendra Ghate and Pavlos Kollias.

  11. 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

  12. arctic boundary layer: Topics by E-print Network

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

    of many theoretical studies over the last forty years. (A Davies, Christopher 18 Tropical cyclone boundary layer shocks CERN Preprints Summary: This paper presents numerical...

  13. atmosphere boundary layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  14. atmospheric boundary layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  15. atmospheric boundary layers: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  16. Overcoming the Boundary Layer Turbulence at Dome C: Ground-Layer Adaptive Optics versus Tower

    E-Print Network [OSTI]

    Ashley, Michael C. B.

    Overcoming the Boundary Layer Turbulence at Dome C: Ground-Layer Adaptive Optics versus Tower T the boundary layer: mounting a telescope on a tower that physically puts it above the turbulent layer such a goal, two solutions can be proposed. The most intuitive one is to place a telescope on a tower

  17. 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

  18. The impact of explicit cloud boundary information on ice cloud microphysical property retrievals from infrared radiances

    E-Print Network [OSTI]

    Stephens, Graeme L.

    from infrared radiances Steven J. Cooper, Tristan S. L'Ecuyer, and Graeme L. Stephens Department inclusion of explicit cloud boundary information from complementary sensors as well as providing a suite of diagnostic tools for evaluating the dominant sources of uncertainty in all retrieved quantities. Errors

  19. Analytic Model of the Universal Structure of Turbulent Boundary Layers

    E-Print Network [OSTI]

    Victor S. L'vov; Itamar Procaccia; Oleksii Rudenko

    2006-06-21T23:59:59.000Z

    Turbulent boundary layers exhibit a universal structure which nevertheless is rather complex, being composed of a viscous sub-layer, a buffer zone, and a turbulent log-law region. In this letter we present a simple analytic model of turbulent boundary layers which culminates in explicit formulae for the profiles of the mean velocity, the kinetic energy and the Reynolds stress as a function of the distance from the wall. The resulting profiles are in close quantitative agreement with measurements over the entire structure of the boundary layer, without any need of re-fitting in the different zones.

  20. ARM: ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

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

    Coulter, Richard; Widener, Kevin; Bharadwaj, Nitin; Johnson, Karen; Martin, Timothy

    ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  1. Long-term Observations of the Convective Boundary Layer Using Insect Radar Returns at the SGP ARM Climate Research Facility

    SciTech Connect (OSTI)

    Chandra, A S; Kollias, P; Giangrande, S E; Klein, S A

    2009-08-20T23:59:59.000Z

    A long-term study of the turbulent structure of the convective boundary layer (CBL) at the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) Climate Research Facility is presented. Doppler velocity measurements from insects occupying the lowest 2 km of the boundary layer during summer months are used to map the vertical velocity component in the CBL. The observations cover four summer periods (2004-08) and are classified into cloudy and clear boundary layer conditions. Profiles of vertical velocity variance, skewness, and mass flux are estimated to study the daytime evolution of the convective boundary layer during these conditions. A conditional sampling method is applied to the original Doppler velocity dataset to extract coherent vertical velocity structures and to examine plume dimension and contribution to the turbulent transport. Overall, the derived turbulent statistics are consistent with previous aircraft and lidar observations. The observations provide unique insight into the daytime evolution of the convective boundary layer and the role of increased cloudiness in the turbulent budget of the subcloud layer. Coherent structures (plumes-thermals) are found to be responsible for more than 80% of the total turbulent transport resolved by the cloud radar system. The extended dataset is suitable for evaluating boundary layer parameterizations and testing large-eddy simulations (LESs) for a variety of surface and cloud conditions.

  2. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,

  3. Distributed boundary layer suction utilizing wing tip effects

    E-Print Network [OSTI]

    Edwards, Jay Thomas

    1962-01-01T23:59:59.000Z

    of this system to existing light aircraft would present no mechanical complications, either in the perforation of the wings or in the maintenance of the system. Recommendations for Other A lications 1. An investigation into the possibility of delaying... Means of Effecting Boundary Layer Control by Suction, " Aeronautical En ineerin Review, September, 1953. 17. Cornish, J. , "Practical High Lift Systems Using Distributed Boundary Layer Control, " Research Report $19, Miss. State College, 1958. 18...

  4. 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.

  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, 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.

  6. Comparison between active sensor and radiosonde cloud boundaries over the ARM Southern Great Plains site

    E-Print Network [OSTI]

    to test the strengths and limitations of cloud boundary retrievals from radiosonde profiles, 4 yearsComparison between active sensor and radiosonde cloud boundaries over the ARM Southern Great Plains radiosonde-based methods applied to 200 m resolution profiles obtained at the same site. The lidar

  7. THE SIMULATION OF FINE SCALE NOCTURNAL BOUNDARY LAYER MOTIONS WITH A MESO-SCALE ATMOSPHERIC MODEL

    SciTech Connect (OSTI)

    Werth, D.; Kurzeja, R.; Parker, M.

    2009-04-02T23:59:59.000Z

    A field project over the Atmospheric Radiation Measurement-Clouds and Radiation Testbed (ARM-CART) site during a period of several nights in September, 2007 was conducted to explore the evolution of the low-level jet (LLJ). Data was collected from a tower and a sodar and analyzed for turbulent behavior. To study the full range of nocturnal boundary layer (NBL) behavior, the Regional Atmospheric Modeling System (RAMS) was used to simulate the ARM-CART NBL field experiment and validated against the data collected from the site. This model was run at high resolution, and is ideal for calculating the interactions among the various motions within the boundary layer and their influence on the surface. The model reproduces adequately the synoptic situation and the formation and dissolution cycles of the low-level jet, although it suffers from insufficient cloud production and excessive nocturnal cooling. The authors suggest that observed heat flux data may further improve the realism of the simulations both in the cloud formation and in the jet characteristics. In a higher resolution simulation, the NBL experiences motion on a range of timescales as revealed by a wavelet analysis, and these are affected by the presence of the LLJ. The model can therefore be used to provide information on activity throughout the depth of the NBL.

  8. Distributed Roughness Receptivity in a Flat Plate Boundary Layer

    E-Print Network [OSTI]

    Kuester, Matthew Scott

    2014-04-18T23:59:59.000Z

    for the three different unit Reynolds num- ber test conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.4 Spanwise uniformity of boundary layer integral quantities at x = 870 mm for low unit Reynolds number test condition... with the distributed roughness configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.5 Differential pressure across the flat plate leading edge. . . . . . . . . . 25 3.6 Roughness patch (k = 1 mm), before windowing . . . . . . . . . . . . 27 3...

  9. Carbon transport in the bottom boundary layer. Final report

    SciTech Connect (OSTI)

    Agrawal, Y.C.

    1998-10-05T23:59:59.000Z

    This report summarizes the activities and findings from a field experiment devised to estimate the rates and mechanisms of transport of carbon across the continental shelves. The specific site chosen for the experiment was the mid-Atlantic Bight, a region off the North Carolina coast. The experiment involved a large contingent of scientists from many institutions. The specific component of the program was the transport of carbon in the bottom boundary layer. The postulate mechanisms of transport of carbon in the bottom boundary layer are: resuspension and advection, downward deposition, and accumulation. The high turbulence levels in the bottom boundary layer require the understanding of the coupling between turbulence and bottom sediments. The specific issues addressed in the work reported here were: (a) What is the sediment response to forcing by currents and waves? (b) What is the turbulence climate in the bottom boundary layer at this site? and (c) What is the rate at which settling leads to carbon sequestering in bottom sediments at offshore sites?

  10. On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

    SciTech Connect (OSTI)

    Kazil, J.; Feingold, G.; Wang, Hailong; Yamaguchi, T.

    2014-01-02T23:59:59.000Z

    The interaction between marine boundary layer cellular cloudiness and surface uxes of sensible and latent heat is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to conduct cloud-system-resolving simulations with interactive surface fluxes of sensible heat, latent heat, and of sea salt aerosol, and with a detailed representation of the interaction between aerosol particles and clouds. The mechanisms responsible for the temporal evolution and spatial distribution of the surface heat fluxes in the closed- and open-cell state are investigated and explained. It is found that the horizontal spatial structure of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of surface air temperature and water vapor, and, to a lesser degree, of the surface sensible and latent heat flux. The synchronized dynamics of the the open-cell state drives oscillations in surface air temperature, water vapor, and in the surface fluxes of sensible and latent heat, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are identified as good predictors of the spatial distribution of surface air temperature and sensible heat flux, but not of surface water vapor and latent heat flux. It is shown that by enhancing the surface sensible heat flux, the open-cell state creates conditions by which it is maintained. While the open-cell state under consideration is not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it also enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted conditions, this enhancement may replenish the aerosol needed for cloud formation, and hence contribute to the perpetuation of the open-cell state as well. Spatial homogenization of the surface fluxes is found to have only a small effect on cloud properties in the investigated cases. This indicates that sub-grid scale spatial variability in the surface flux of sensible and latent heat and of sea salt aerosol may not be required in large scale and global models to describe marine boundary layer cellular cloudiness.

  11. ARM - Field Campaign - Boundary Layer CO2 Using CW Lidar

    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)8Li (59AJ76)ARM2,govCampaignsAircraftCloud ODgovCampaignsBoundary

  12. Polymer Effects on Heat Transport in Laminar Boundary Layer Flow

    E-Print Network [OSTI]

    Roberto Benzi; Emily S. C. Ching; Vivien W. S. Chu

    2011-04-27T23:59:59.000Z

    We consider a laminar Blasius boundary-layer flow above a slightly heated horizontal plate and study the effect of polymer additives on the heat transport. We show that the action of the polymers can be understood as a space-dependent effective viscosity that first increases from the zero-shear value then decreases exponentially back to the zero-shear value as one moves away from the boundary. We find that with such an effective viscosity, both the horizontal and vertical velocities near the plate are decreased thus leading to an increase in the friction drag and a decrease in the heat transport in the flow.

  13. Examining A Hypersonic Turbulent Boundary Layer at Low Reynolds Number

    E-Print Network [OSTI]

    Semper, Michael Thomas

    2013-05-15T23:59:59.000Z

    z spanwise direction, m Greek Symbols boundary layer thickness, m displacement thickness, m ratio of speci c heats hotwire recovery ratio dynamic viscosity, Pa s density, kg=m3 hotwire overheat ratio, Twire=Tt momentum thickness, m... direct numerical simulation LDV laser doppler velocimetry LES large eddy simulation MTV molecular tagging velocimetry OHR overheat ratio (see ) PIV particle image velocimetry PLIF planar laser induced uorescence RANS Reynolds averaged Navier...

  14. Coupled wake boundary layer model of wind-farms

    E-Print Network [OSTI]

    Stevens, Richard J A M; Meneveau, Charles

    2014-01-01T23:59:59.000Z

    We present and test a coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake expansion/superposition approach with a top-down model for the overall wind-farm boundary layer structure. The wake expansion/superposition model captures the effect of turbine positioning, while the top-down portion adds the interaction between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model the wake expansion coefficient is required, while the top-down model requires an effective span-wise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective span-wise turbine spacing depends on turbine positioning and thus can be determined from the wake expansion...

  15. A case study of boundary layer ventilation by convection and coastal processes

    E-Print Network [OSTI]

    Dacre, Helen

    A case study of boundary layer ventilation by convection and coastal processes H. F. Dacre,1 S. L; published 12 September 2007. [1] It is often assumed that ventilation of the atmospheric boundary layer responsible for ventilation of the atmospheric boundary layer during a nonfrontal day that occurred on 9 May

  16. BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010

    E-Print Network [OSTI]

    BOUNDARY LAYER (BL) THERMAL EDDIES OVER A PINE FOREST FROM CARES 2010 Gunnar Senum and Stephen are three thermal eddies, about 250 meters wide, in the boundary layer. These thermal eddies are formed from the solar heating of the surface and help to form the boundary layer. The eddy updrafts are transporting

  17. Numerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples

    E-Print Network [OSTI]

    Slinn, Donald

    locations. Under conditions of oscillatory potential flow external to the boundary layer causedNumerical Simulations of the Wave Bottom Boundary Layer over Sand Ripples by Thomas Pierro A Thesis boundary layer are believed to play a major role in the re-suspension and transport of sediment, as well

  18. A new cloud and aerosol layer detection method based on micropulse lidar measurements

    E-Print Network [OSTI]

    Li, Zhanqing

    A new cloud and aerosol layer detection method based on micropulse lidar measurements Chuanfeng algorithm to detect aerosols and clouds based on micropulse lidar measurements. A semidiscretization is then introduced. Combined with empirical threshold values, we determine if the signal waves indicate clouds

  19. Thermographic analysis of turbulent non-isothermal water boundary layer

    E-Print Network [OSTI]

    Znamenskaya, Irina A

    2015-01-01T23:59:59.000Z

    The paper is devoted to the investigation of the turbulent water boundary layer in the jet mixing flows using high-speed infrared (IR) thermography. Two turbulent mixing processes were studied: a submerged water jet impinging on a flat surface and two intersecting jets in a round disc-shaped vessel. An infrared camera (FLIR Systems SC7700) was focused on the window transparent for IR radiation; it provided high-speed recordings of heat fluxes from a thin water layer close to the window. Temperature versus time curves at different points of water boundary layer near the wall surface were acquired using the IR camera with the recording frequency of 100 Hz. The time of recording varied from 3 till 20 min. The power spectra for the temperature fluctuations at different points on the hot-cold water mixing zone were calculated using the Fast Fourier Transform algorithm. The obtained spectral behavior was compared to the Kolmogorov "-5/3 spectrum" (a direct energy cascade) and the dual-cascade scenario predicted for...

  20. 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.

  1. Applications of Fourier analysis in homogenization and boundary layer

    E-Print Network [OSTI]

    Aleksanyan, Hayk; Sjölin, Per

    2012-01-01T23:59:59.000Z

    In this paper we prove convergence results for the boundary layer homogenization problem for solutions of partial differential system with rapidly oscillating Dirichlet data. Our method is based on analysis of oscillatory integrals. In the uniformly convex regime and smooth boundaries we prove pointwise as well as $L^p$ convergence results. Namely, we prove $|u_{\\e}(x)-u_0 (x)| \\leq C_{\\kappa} \\e^{(d-1)/2}\\frac{1}{d(x)^{\\kappa}}$, $\\forall x\\in D$, $ \\forall \\ \\kappa>d-1$, and for $1\\leq pboundary of $D$. In particular for $p=2$ our result relates to the recent result of D. G\\'{e}rarad-Varet and N. Masmoudi \\cite{GM}.

  2. Aerodynamic Models for Hurricanes III. Modeling hurricane boundary layer

    E-Print Network [OSTI]

    Leonov, Arkady I

    2008-01-01T23:59:59.000Z

    The third paper of the series (see previous ones in Refs.[1-2]) discusses basic physicalprocesses in the (quasi-) steady hurricane boundary layer (HBL), develops an approximate airflow model, establishes the HBL structure, and presents integral balance relations for dynamic and thermodynamic variables in HBL. Models of evaporation and condensation are developed, where the condensation is treated similarly to the slow combustion theory. A turbulent approximation for the lower sub-layer of HBL is applied to the sea-air interaction to establish the observed increase in angular momentum in the outer region of HBL.A closed set of balance relations has been obtained. Simple analytical solution of the set yields expressions for the basic dynamic variables - maximal tangential and radial velocities in hurricane, maximal vertical speed in eye wall, the affinity speed of hurricane travel, and the maximal temperature increase after condensation. Estimated values of the variables seem to be realistic. An attempt is also ...

  3. Delaying natural transition of a boundary layer using smooth steps

    E-Print Network [OSTI]

    Xu, Hui; Sherwin, Spencer J

    2015-01-01T23:59:59.000Z

    The boundary layer flow over a smooth forward-facing stepped plate is studied with particular emphasis on the delay of the transition to turbulence. The interaction between the Tollmien-Schlichting (T-S) waves and the base flow over a single/two forward facing smooth steps is conducted by linear analysis indicating the amplitude of the T-S waves are attenuated in the boundary layer over a single smooth plate. Furthermore, we show that two smooth forward facing steps give rise to a further reduction of the amplitude of the T-S waves. A direct numerical simulation (DNS) is performed for the two smooth forward steps correlating favourably with the linear analysis and showing that for the investigated parameters, the K-type transition is inhibited whereas the turbulence onset of the H-type transition is postponed albeit not suppressed. Transition is indeed delayed and drag reduced for both these transition scenarios suggesting smooth forward facing steps could be leveraged as a passive flow control strategy to de...

  4. Laminar-turbulent separatrix in a boundary layer flow

    E-Print Network [OSTI]

    Biau, Damien

    2013-01-01T23:59:59.000Z

    The transitional boundary layer flow over a flat plate is investigated. The boundary layer flow is known to develop unstable Tollmien-Schlichting waves above a critical value of the Reynolds number. However, it is also known that this transition can be observed for sub-critical Reynolds numbers. In that case, the basin of attraction of the laminar state coexists with the sustained turbulence. In this article, the trajectory on the separatrix between these two states is simulated. The state on the separatrix is independent from the initial condition and is dynamically connected to both the laminar flow and the turbulence. Such an edge state provides information regarding the basic features of the transitional flow. The solution takes the form of a low speed streak, flanked by two quasi-streamwise sinuous vortices. The shape of the streaks is close to that simulated with the linear optimal perturbation method. This solution is compared to existing results concerning streak breakdown. The simulations are realize...

  5. Vertical Velocities in Continental Boundary Layer Stratocumulus Clouds

    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 Maps1 - USAFof EnergyVendorwinsVenue andVertical

  6. ARM: 10-minute Raman Lidar: aerosol depolarization profiles and single layer cloud optical depths from first Turner algorithm

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

    Newsom, Rob; Goldsmith, John

    10-minute Raman Lidar: aerosol depolarization profiles and single layer cloud optical depths from first Turner algorithm

  7. Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary conditions

    E-Print Network [OSTI]

    Kudrolli, Arshad

    Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before

  8. Characterization of Oscillatory Boundary Layer over a Closely Packed Bed of

    E-Print Network [OSTI]

    Apte, Sourabh V.

    Characterization of Oscillatory Boundary Layer over a Closely Packed Bed of Sediment Particles Boundary Layer over a Closely Packed Bed of Sediment Particles Chaitanya D. Ghodke*, Joseph Skitka a detailed knowledge of the small amplitude oscillatory flow over the sediment layer near the sea bed. Fully

  9. Heat transport by laminar boundary layer flow with polymers

    E-Print Network [OSTI]

    Roberto Benzi; Emily S. C. Ching.; Vivien W. S. Chu

    2011-04-23T23:59:59.000Z

    Motivated by recent experimental observations, we consider a steady-state Prandtl-Blasius boundary layer flow with polymers above a slightly heated horizontal plate and study how the heat transport might be affected by the polymers. We discuss how a set of equations can be derived for the problem and how these equations can be solved numerically by an iterative scheme. By carrying out such a scheme, we find that the effect of the polymers is equivalent to producing a space-dependent effective viscosity that first increases from the zero-shear value at the plate then decreases rapidly back to the zero-shear value far from the plate. We further show that such an effective viscosity leads to an enhancement in the drag, which in turn leads to a reduction in heat transport.

  10. Primary, secondary instabilities and control of the rotating-disk boundary layer

    E-Print Network [OSTI]

    ;Typical 3D boundary layers rotating disk swept wing Common features: · crossflow component near the wall · inflection point · strong inviscid instability · secondary instabilities ; growth and saturation of crossflow

  11. Comparison of reflection boundary conditions for langevin equation modeling of convective boundary layer dispersion

    SciTech Connect (OSTI)

    Nasstrom, J.S.; Ermak, D.L.

    1997-04-01T23:59:59.000Z

    Lagrangian stochastic modeling based on the Langevin equation has been shown to be useful for simulating vertical dispersion of trace material in the convective boundary layer or CBL. This modeling approach can account for the effects of the long velocity correlation time scales, skewed vertical velocity distributions, and vertically inhomogeneous turbulent properties found in the CBL. It has been recognized that Langevin equation models assuming skewed but homogenous velocity statistics can capture the important aspects of diffusion from sources in the CBL, especially elevated sources. We compare three reflection boundary conditions using two different Langevin-equation-based numerical models for vertical dispersion in skewed, homogeneous turbulence. One model, described by Ermak and Nasstrom (1995) is based on a Langevin equation with a skewed random force and a linear deterministic force. The second model, used by Hurley and Physick (1993) is based on a Langevin equation with a Gaussian random force and a non-linear deterministic force. The reflection boundary conditions are all based on the approach described by Thompson and Montgomery (1994).

  12. TOWARDS A CLOUD CEILOMETER NETWORK REPORTING MIXING LAYER HEIGHT Wiel M.F. Wauben

    E-Print Network [OSTI]

    Wauben, Wiel

    profiles if the aerosol concentrations are not too low. Since aerosol is well mixed in the atmospheric in the backscatter profile (cf. Wauben et al., 2006). Sometimes, medium and low clouds can also be missed or falsely1 TOWARDS A CLOUD CEILOMETER NETWORK REPORTING MIXING LAYER HEIGHT Wiel M.F. Wauben 1 , Marijn de

  13. Evolution of Prolate Molecular Clouds at Hii Boundaries: II. Formation of BRCs of asymmetrical morphology

    E-Print Network [OSTI]

    Kinnear, T M; White, G J; Sugitani, K; Goodwin, S

    2015-01-01T23:59:59.000Z

    A systematic investigation on the evolution of a prolate cloud at an Hii boundary is conducted using Smoothed Particle Hydrodynamics (SPH) in order to understand the mechanism for a variety of irregular morphological structures found at the boundaries of various Hii regions. The prolate molecular clouds in this investigation are set with their semi-major axes at inclinations between 0 and 90 degrees to a plane parallel ionizing radiation flux. A set of 4 parameters, the number density n, the ratio of major to minor axis gamma, the inclination angle phi and the incident flux F_EUV, are used to define the initial state of the simulated clouds. The dependence of the evolution of a prolate cloud under Radiation Driven Implosion (RDI) on each of the four parameters is investigated. It is found that: i) in addition to the well studied standard type A, B or C Bright Rimmed Clouds (BRCs), many other types such as asymmetrical BRCs, filamentary structures and irregular horse-head structures could also be developed at ...

  14. Bottom boundary layer measurements in OMP. Final report

    SciTech Connect (OSTI)

    Gross, T.F. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Williams, A.J. [Woods Hole Oceanographic Inst., MA (United States)

    1998-11-01T23:59:59.000Z

    The main role of the Benthic Acoustic Stress Sensor (BASS) tripods within the Ocean Margins Program experiments was to detect and quantify organic carbon rich particle transport off the shelf. This requires measures of the turbulent boundary layer flow and bed stress, the physical forcing of the particle transport, as well as the concentration and type of particles which are being transported. The BASS tripods were deployed at sites 17 and 26. Data from site 26 were recovered spanning three periods: Feb. 2--April 6, May 13--June 27, June 28--Aug. 18. Site 17 was occupied Feb. 12--april 11. The BASS tripods were arrayed with five BASS sensors measuring detailed velocity parameters within four meters of the seabed. Velocity time series indicate a usually weak tidal flow which produces small bed stress by itself. On the occasions when a strong flow, probably the Gulf Stream, crosses the area, the bed shear stress increases dramatically to as much as 10 dyne cm{sup {minus}2}. This is competent to move unconsolidated sediments in the area. Other instruments from the tripods include: two conductivity/temperature sensor pairs, five WetStar fluorometers, thermistors, transmissometer, optical backscatterence sensors and a pressure sensor.

  15. EXPERIMENTAL STUDY OF COMBUSTION IN A TURBULENT BOUNDARY LAYER

    E-Print Network [OSTI]

    Cheng, R.K.

    2011-01-01T23:59:59.000Z

    evaporation, but the thermophoretic migration of particlesboundary layer due to thermophoretic motion and evaporation

  16. F/sub 2/ boundary layer measurement in a chemical laser slit nozzle flow

    SciTech Connect (OSTI)

    Spenser, D.J.; Durran, D.A.; Bixler, H.A.; Varwig, R.L.

    1983-02-01T23:59:59.000Z

    A sensitive F2 absorption diagnostic suitable for slit nozzle scanning was developed and applied to the measurement of an F2 boundary layer in an HF chemical laser flow. The F2 boundary layer profile was determined to be of exponential decay form with peak at the nozzle wall and of width approx. 1/3 the viscous boundary layer. The F2 concentration profile was displaced inwardly and slightly compressed by the H2 slit injection at the nozzle exit plane. The F2 profile apparently remains fairly intact in passing through the lasing zone.

  17. Design of a model propulsor for a boundary layer ingesting aircraft

    E-Print Network [OSTI]

    Grasch, Adam D. (Adam Davis)

    2013-01-01T23:59:59.000Z

    This thesis presents contributions to the analysis and design of propulsion simulators for 1:11 and 1:4 scale model wind tunnel investigations of an advanced civil transport aircraft with boundary layer ingestion (BLI). ...

  18. Boundary-Layer Receptivity to Three-Dimensional Roughness Arrays on a Swept-Wing

    E-Print Network [OSTI]

    Hunt, Lauren Elizabeth

    2012-02-14T23:59:59.000Z

    is required. This study uses detailed hotwire boundary-layer velocity scans to quantify the relationship between roughness height and initial disturbance amplitude. Naphthalene flow visualization provides insight into how transition changes as a result...

  19. Advances in the visualization and analysis of boundary layer flow in swimming fish

    E-Print Network [OSTI]

    Anderson, Erik J

    2005-01-01T23:59:59.000Z

    In biology, the importance of fluid drag, diffusion, and heat transfer both internally and externally, suggest the boundary layer as an important subject of investigation, however, the complexities of biological systems ...

  20. Stability Analysis for a Saline Boundary Layer Formed by Uniform Up ow Using Finite Elements

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    density in the deeper underground and high salt water density at the boundary layer), gravitation plays and Darcy's law. In this report we #12;rst give an overview of semi-analytical methods to analyse

  1. The hydrodynamic stability of crossflow vortices in the Bdewadt boundary layer

    E-Print Network [OSTI]

    The hydrodynamic stability of crossflow vortices in the Bödewadt boundary layer N. A. Culverhouse the critical Reynolds number. extends the laminar flow region. decreasing the magnitude of the crossflow

  2. Analysis and interpretation of tidal currents in the coastal boundary layer

    E-Print Network [OSTI]

    May, Paul Wesley, 1950-

    1979-01-01T23:59:59.000Z

    Concern with the impact of human activities on the coastal region of the world's oceans has elicited interest in the so-called "coastal boundary layer"-that band of water adjacent to the coast where ocean currents adjust ...

  3. The aerodynamic characteristics of an airfoil utilizing boundary layer and circulation control

    E-Print Network [OSTI]

    Boothe, Edward Milton

    1965-01-01T23:59:59.000Z

    THE AERODYNAMIC CHARACTERISTICS OF AN AIRFOIL UTILIZING BOUNDARY LAYER AND CIRCULATION CONTROL A Thesis By EDWARD MILTON BOOTHE Submitted to the Graduate College of the Texas ARM University in partial fulfillment of the requirements... . Wind Tunnel IV Auxiliary Equipment EXPERIMENTAL PROCEDURES . 13 Preliminary Tests 13 Measurement of Boundary Layer And Circulation Control Parameters 16 Wind Tunnel Tests of Airfoil Model. 19 Reduction of Experimental Results 20 V RESULTS...

  4. Design of an Instrumentation System for a Boundary Layer Transition Wing Glove Experiment 

    E-Print Network [OSTI]

    Williams, Thomas 1987-

    2012-08-23T23:59:59.000Z

    of Air * Complex Conjugate CF Crossflow CFD Computational Fluid Dynamics ! Skin Friction Coefficient cgr,n Group Velocity Measured by Sensor-n CN ASHRAE Clearness Factor for Solar Radiation ! Pressure Coefficient !" Specific Heat of Air... Test Engineer Acceleration due to Gravity G-III Gulfstream G-III Business Jet !" Crossflow Similarity Variable for the Falkner-Scan-Cooke Boundary Layer !"! Value of Crossflow Similarity Variable for the Falkner-Scan-Cooke Boundary Layer...

  5. 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

  6. EART 265 Lecture Notes: Boundary Layers We're interested here mainly in boundary layers relevant to planets, i.e. those of planetary atmo-

    E-Print Network [OSTI]

    Nimmo, Francis

    and the surface, thus mediating all interactions between the two. If we look back at the Navier-Stokes equations of a solid (or liquid in the case of gas ows) where diusion is non-negligible. It is characterized by strong then promotes mixing. Outside the boundary layer, uid often mixes only very slowly because turbulence

  7. 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

  8. Technical Tools for Boundary Layers and Applications to Heterogeneous Coefficients

    E-Print Network [OSTI]

    Sarkis, Marcus

    , Poland. This work was supported in part by the Polish Sciences Foundation under grant NN201006933. 2 energy in a thin layer and vice versa, how to control the energy of a discrete harmonic function

  9. Combustion-turbulence interaction in the turbulent boundary layer over a hot surface

    SciTech Connect (OSTI)

    Ng, T.T.; Cheng, R.K.; Robben, F.; Talbot, L.

    1982-01-01T23:59:59.000Z

    The turbulence-combustion interaction in a reacting turbulent boundary layer over a heated flat plate was studied. Ethylene/air mixture with equivalence ratio of 0.35 was used. The free stream velocity was 10.5 m/s and the wall temperature was 1250/sup 0/K. Combustion structures visualization was provided by high-speed schlieren photographs. Fluid density statistics were deduced from Rayleigh scattering intensity measurements. A single-component laser Doppler velocimetry system was used to obtain mean and root-mean-square velocity distributions, the Reynolds stress, the streamwise and the cross-stream turbulent kinetic energy diffusion, and the production of turbulent kinetic energy by Reynolds stress. The combustion process was dominated by large-scale turbulent structures of the boundary layer. Combustion causes expansion of the boundary layer. No overall self-similarity is observed in either the velocity or the density profiles. Velocity fluctuations were increased in part of the boundary layer and the Reynolds stress was reduced. The turbulent kinetic energy diffusion pattern was changed significantly and a modification of the boundary layer assumption will be needed when dealing with this problem analytically. 11 figures, 1 table.

  10. PLASMOID RELEASES IN THE HELIOSPHERIC CURRENT SHEET AND ASSOCIATED CORONAL HOLE BOUNDARY LAYER EVOLUTION

    SciTech Connect (OSTI)

    Foullon, C. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Lavraud, B.; Opitz, A.; Sauvaud, J.-A. [Institut de Recherche en Astrophysique et Planetologie (IRAP), Universite de Toulouse (UPS) and Centre National de la Recherche Scientifique, UMR 5277, Toulouse (France); Luhmann, J. G. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); Farrugia, C. J.; Simunac, K. D. C.; Galvin, A. B.; Kucharek, H.; Popecki, M. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Retino, A. [Laboratoire de Physique des Plasmas-CNRS, Observatoire de Saint-Maur, 4 avenue de Neptune, Saint-Maur-Des-Fosses, 94107 (France); Wardle, N. C.; Owen, C. J., E-mail: claire.foullon@warwick.ac.uk [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2011-08-10T23:59:59.000Z

    As the heliospheric current sheet (HCS) is corotating past STEREO-B, near-Earth spacecraft ACE, Wind and Cluster, and STEREO-A over more than three days between 2008 January 10 and 14, we observe various sections of (near-pressure-balanced) flux-rope- and magnetic-island-type plasmoids in the associated heliospheric plasma sheet (HPS). The plasmoids can qualify as slow interplanetary coronal mass ejections and are relatively low proton beta (<0.5) structures, with small length scales (an order of magnitude lower than typical magnetic cloud values) and low magnetic field strengths (2-8 nT). One of them, in particular, detected at STEREO-B, corresponds to the first reported evidence of a detached plasmoid in the HPS. The in situ signatures near Earth are associated with a long-decay X-ray flare and a slow small-scale streamer ejecta, observed remotely with white-light coronagraphs aboard STEREO-B and SOHO and tracked by triangulation. Before the arrival of the HPS, a coronal hole boundary layer (CHBL) is detected in situ. The multi-spacecraft observations indicate a CHBL stream corotating with the HCS but with a decreasing speed distribution suggestive of a localized or transient nature. While we may reasonably assume that an interaction between ejecta and CHBL provides the source of momentum for the slow ejecta's acceleration, the outstanding composition properties of the CHBL near Earth provide here circumstantial evidence that this interaction or possibly an earlier one, taking place during streamer swelling when the ejecta rises slowly, results in additional mixing processes.

  11. Observations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget along 208S

    E-Print Network [OSTI]

    Yuter, Sandra

    of cloud properties and drizzle statistics, and the effect of stratocumulus clouds on surface radiationObservations of Stratocumulus Clouds and Their Effect on the Eastern Pacific Surface Heat Budget gradients in boundary layer and cloud vertical structure, surface radiation and cloud radiative forcing

  12. 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

  13. F/sup 2/ boundary layer measurement in a chemical laser slit nozzle flow. Technical report

    SciTech Connect (OSTI)

    Spencer, D.J.; Durran, D.A.; Bixler, H.A.; Varwig, R.L.

    1983-02-15T23:59:59.000Z

    A sensitive F/sup 2/ absorption diagnostic suitable for slit nozzle scanning was developed and applied to the measurement of an F/sup 2/ boundary layer in an HF chemical laser flow. The F/sup 2/ boundary layer profile was determined to be of exponential decay form with peak at the nozzle wall and of width approx. 1/3 the viscous boundary layer. The F/sup 2/ concentration profile was displaced inwardly and slightly compressed by the H2 slit injection at the nozzle exit plane, which penetration profile followed the relation delta = 0.1(sq. root of x). The F/sup 2/ profile apparently remains fairly intact in passing through the lasing zone.

  14. 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

  15. Wind Energy-Related Atmospheric Boundary Layer Large-Eddy Simulation Using OpenFOAM: Preprint

    SciTech Connect (OSTI)

    Churchfield, M.J.; Vijayakumar, G.; Brasseur, J.G.; Moriarty, P.J.

    2010-08-01T23:59:59.000Z

    This paper develops and evaluates the performance of a large-eddy simulation (LES) solver in computing the atmospheric boundary layer (ABL) over flat terrain under a variety of stability conditions, ranging from shear driven (neutral stratification) to moderately convective (unstable stratification).

  16. ESTIMATING BEDROCK AND SURFACE LAYER BOUNDARIES AND CONFIDENCE INTERVALS IN ICE SHEET RADAR IMAGERY USING MCMC

    E-Print Network [OSTI]

    Menczer, Filippo

    ESTIMATING BEDROCK AND SURFACE LAYER BOUNDARIES AND CONFIDENCE INTERVALS IN ICE SHEET RADAR IMAGERY and Computing Indiana University Bloomington, Indiana USA ABSTRACT Climate models that predict polar ice sheet behavior require accurate measurements of the bedrock-ice and ice-air bound- aries in ground

  17. Sensitivity of Swept-Wing, Boundary-Layer Transition to Spanwise-Periodic Discrete Roughness Elements

    E-Print Network [OSTI]

    West, David Edward

    2014-12-12T23:59:59.000Z

    Micron-sized, spanwise-periodic, discrete roughness elements (DREs) were applied to and tested on a 30° swept-wing model in order to study their effects on boundary-layer transition in flight where stationary crossflow waves are the dominant...

  18. Wave-driven wind jets in the marine atmospheric boundary layer

    E-Print Network [OSTI]

    Reading, University of

    Wave-driven wind jets in the marine atmospheric boundary layer Kirsty E. Hanley Stephen E. Belcher;Abstract The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum can also be transferred upwards when long wavelength waves, characteristic of re- motely generated

  19. Behavior of Turbulent Structures within a Mach 5 Mechanically Distorted Boundary Layer

    E-Print Network [OSTI]

    Peltier, Scott Jacob

    2013-08-05T23:59:59.000Z

    field of incompressible boundary layer, taken from Adrian et al. (2000). ............................................................................... 138 Figure 6.15 Schematic of an individual hairpin vortex, describing the sweep and ejection... hairpin vortex, identifying the motions contributing to sweeps and ejections ....................................................................................... 235 Figure 7.46 Illustrations of the possible mechanisms contributing to the reduced...

  20. American Institute of Aeronautics and Astronautics Shock/Boundary Layer Interaction Effects of Transverse

    E-Print Network [OSTI]

    Texas at Arlington, University of

    of Transverse Jets in Crossflow over a Body of Revolution Dean A. Dickmann* Lockheed Martin Missiles and Fire 76019 Shock/boundary layer interaction present in transverse jets in supersonic crossflow alteres suggested a transverse jet in crossflow can be represented by a solid body of given length and shape

  1. Flowfield and wall pressure characteristics downstream of a boundary layer suction device.

    E-Print Network [OSTI]

    Tinney, Charles E.

    Flowfield and wall pressure characteristics downstream of a boundary layer suction device. Meagan A-dimensional slit can significantly reduce the fluctuating wall pressure immediately downstream of the suction slit momentum regions of the flow with the wall at the downstream edge of the suction slit. The third region

  2. Local and Bi-Global Stability Analysis of a Plasma Actuated Boundary Layer

    E-Print Network [OSTI]

    Roy, Subrata

    velocities ¯p Mean pressure ~u, ~v, ~w Disturbance flow velocities ~p Disturbance pressure u , v , w Complex disturbance flow velocities p Complex disturbance pressure u Freestream velocity up Induced velocity Complex spatial frequency in x Complex spatial frequency in z Complex temporal frequency 99% Boundary layer

  3. Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena: Katabatic winds and boundary layer convection

    E-Print Network [OSTI]

    Spiga, Aymeric

    Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena Keywords: Mesoscale meteorology Katabatic winds Boundary layer convection Comparative planetology a b s t r a c t Terrestrial and Martian atmospheres are both characterised by a large variety of mesoscale

  4. Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical Pacific marine boundary layer

    E-Print Network [OSTI]

    Russell, Lynn

    Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical in the remote subtropical Pacific marine boundary layer, J. Geophys. Res., 111, D02206, doi:10.1029/2004JD005694 the boundary layer via its action on the budgets of heat and water substance. A plausible consequence may

  5. Resuspension of Small Particles from Multilayer Deposits in Turbulent Boundary Layers

    E-Print Network [OSTI]

    F. Zhang; M. Reeks; M. Kissane; R. J. Perkins

    2012-06-09T23:59:59.000Z

    We present a hybrid stochastic model for the resuspension of micron-size particles from multilayer deposits in a fully-developed turbulent boundary layer. The rate of removal of particles from any given layer depends upon the rate of removal of particles from the layer above which acts as a source of uncovering and exposure of particles to the resuspending flow. The primary resuspension rate constant for an individual particle within a layer is based on the Rock'n'Roll (R'n'R) model using non-Gaussian statistics for the aerodynamic forces acting on the particles (Zhang et al., 2012). The coupled layer equations that describe multilayer resuspension of all the particles in each layer are based on the generic lattice model of Friess & Yadigaroglu (2001) which is extended here to include the influence of layer coverage and particle size distribution. We consider the influence of layer thickness on the resuspension along with the spread of adhesion within layers, and the statistics of non-Gaussian versus Gaussian removal forces including their timescale. Unlike its weak influence on long-term resuspension rates for monolayers, this timescale plays a crucial and influential role in multilayer resuspension. Finally we compare model predictions with those of a large-scale and a mesoscale resuspension test, STORM (Castelo et al., 1999) and BISE (Alloul-Marmor, 2002).

  6. Blockage of natural convection boundary layer flow in a multizone enclosure

    SciTech Connect (OSTI)

    Scott, D.; Anderson, R.; Figliola, R.S.

    1986-02-01T23:59:59.000Z

    This paper reports the results of an experimental study that examines the transition between flow regimes, as a function of aperture size, in a two-zone enclosure with heated and cooled end walls. A constant heat flux boundary condition was maintained on one vertical end wall, and an isothermal cold temperature sink was maintained on the opposite vertical end wall. All of the remaining surfaces were highly insulated. The transition between the boundary layer driven regime and the bulk density driven regime was established as a function of the geometry of the aperture in the partition that separated the hot and cold zones. The results demonstrate that transition from the boundary layer driven regime to the bulk density driven regime is caused by blockage of the boundary layer flow, when the area of the flow aperture is reduced below a critical value. A simple flow model has been developed which predicts that the critical aperture area for the onset of flow blockage is directly proportional to the number of active heat transfer surfaces and inversely proportional to the Rayleigh number which characterizes the level of heating and cooling provided to the active heat transfer surfaces.

  7. Quasi-periodic oscillations as global hydrodynamic modes in the boundary layers of viscous accretion disks

    E-Print Network [OSTI]

    M. Hakan Erkut; Dimitrios Psaltis; M. Ali Alpar

    2008-07-28T23:59:59.000Z

    The observational characteristics of quasi-periodic oscillations (QPOs) from accreting neutron stars strongly indicate the oscillatory modes in the innermost regions of accretion disks as a likely source of the QPOs. The inner regions of accretion disks around neutron stars can harbor very high frequency modes related to the radial epicyclic frequency $\\kappa $. The degeneracy of $\\kappa $ with the orbital frequency $\\Omega $ is removed in a non-Keplerian boundary or transition zone near the magnetopause between the disk and the compact object. We show, by analyzing the global hydrodynamic modes of long wavelength in the boundary layers of viscous accretion disks, that the fastest growing mode frequencies are associated with frequency bands around $\\kappa $ and $\\kappa \\pm \\Omega $. The maximum growth rates are achieved near the radius where the orbital frequency $\\Omega $ is maximum. The global hydrodynamic parameters such as the surface density profile and the radial drift velocity determine which modes of free oscillations will grow at a given particular radius in the boundary layer. In accordance with the peak separation between kHz QPOs observed in neutron-star sources, the difference frequency between two consecutive bands of the fastest growing modes is always related to the spin frequency of the neutron star. This is a natural outcome of the boundary condition imposed by the rotating magnetosphere on the boundary region of the inner disk.

  8. 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

  9. Experimental investigation of sound generation by a protuberance in a laminar boundary layer

    SciTech Connect (OSTI)

    Kobayashi, M.; Asai, M.; Inasawa, A. [Department of Aerospace Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065 (Japan)

    2014-08-15T23:59:59.000Z

    Sound radiation from a two-dimensional protuberance glued on the wall in a laminar boundary layer was investigated experimentally at low Mach numbers. When the protuberance was as high as the boundary-layer thickness, a feedback-loop mechanism set in between protuberance-generated sound and Tollmien-Schlichting (T-S) waves generated by the leading-edge receptivity to the upstream-propagating sound. Although occurrence of a separation bubble immediately upstream of the protuberance played important roles in the evolution of instability waves into vortices interacting with the protuberance, the frequency of tonal vortex sound was determined by the selective amplification of T-S waves in the linear instability stage upstream of the separation bubble and was not affected by the instability of the separation bubble.

  10. Viscous boundary layers of radiation-dominated, relativistic jets. II. The free-streaming jet model

    E-Print Network [OSTI]

    Coughlin, Eric R

    2015-01-01T23:59:59.000Z

    We analyze the interaction of a radiation-dominated jet and its surroundings using the equations of radiation hydrodynamics in the viscous limit. In a previous paper we considered the two-stream scenario, which treats the jet and its surroundings as distinct media interacting through radiation viscous forces. Here we present an alternative boundary layer model, known as the free-streaming jet model -- where a narrow stream of fluid is injected into a static medium -- and present solutions where the flow is ultrarelativistic and the boundary layer is dominated by radiation. It is shown that these jets entrain material from their surroundings and that their cores have a lower density of scatterers and a harder spectrum of photons, leading to observational consequences for lines of sight that look "down the barrel of the jet." These jetted outflow models may be applicable to the jets produced during long gamma-ray bursts and super-Eddington phases of tidal disruption events.

  11. Viscous boundary layers of radiation-dominated, relativistic jets. I. The two-stream model

    E-Print Network [OSTI]

    Coughlin, Eric R

    2015-01-01T23:59:59.000Z

    Using the relativistic equations of radiation hydrodynamics in the viscous limit, we analyze the boundary layers that develop between radiation-dominated jets and their environments. In this paper we present the solution for the self-similar, 2-D, plane-parallel two-stream problem, wherein the jet and the ambient medium are considered to be separate, interacting fluids, and we compare our results to those of previous authors. (In a companion paper we investigate an alternative scenario, known as the free-streaming jet model.) Consistent with past findings, we show that the boundary layer that develops between the jet and its surroundings creates a region of low-density material. These models may be applicable to sources such as super-Eddington tidal disruption events and long gamma-ray bursts.

  12. Sangamon field experiments: observations of the diurnal evolution of the planetary boundary layer over land

    SciTech Connect (OSTI)

    Hicks, B.B.; Hess, G.D.; Wesely, M.L.; Yamada, T.; Frenzen, P.; Hart, R.L.; Sisterson, D.L.; Hess, P.E.; Kulhanek, F.C.; Lipschutz, R.C.; Zerbe, G.A.

    1981-09-01T23:59:59.000Z

    Two complementary experimental studies of the evolving structure of the lower 2 km of the atmosphere, conducted over farmlands in central Illinois during essentially the same mid-summer weeks of two successive years, are described. The first experiment (21 July - 13 August 1975) investigated the early morning break up of the nocturnal stable layer and the rapid growth of the mixed layer before noon; the second (16 to 30 July 1976) examined the decline of the mixed layer through the late afternoon and evening, and the formation and intensification of the ground-based inversion before midnight. Methods of observation and data reduction are summarized in some detail, and the data obtained in the form of hourly wind and temperature profiles, plus sufficient surface flux information to characterize the lower boundary conditions, are tabulated in a series of appendices. These results constitute complete data sets which may be used to test models of the diurnal evolution of the lower atmosphere.

  13. Variability of ozone in the marine boundary layer of the equatorial Pacific Ocean1 Xiao-Ming Hu1

    E-Print Network [OSTI]

    Thompson, Anne

    marine boundary layer of the Kwajalein Atoll, Republic of the Marshall Islands (latitude 8o 43'3 N al., 2000; Horowitz et al., 2003; Yang et13 al., 2005; von Glasow, 2008). Due to logistical

  14. An empirical model for the mean-velocity profiles of a turbulent boundary layer under the effects of surface curvature 

    E-Print Network [OSTI]

    Huynh, Long Quang

    1994-01-01T23:59:59.000Z

    An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature...

  15. An empirical model for the mean-velocity profiles of a turbulent boundary layer under the effects of surface curvature

    E-Print Network [OSTI]

    Huynh, Long Quang

    1994-01-01T23:59:59.000Z

    An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature...

  16. Prediction of continental shelf sediment transport using a theoretical model of the wave-current boundary layer

    E-Print Network [OSTI]

    Goud, Margaret R

    1987-01-01T23:59:59.000Z

    This thesis presents an application of the Grant-Madsen-Glenn bottom boundary layer model (Grant and Madsen, 1979; Glenn and Grant, 1987) to predictions of sediment transport on the continental shelf. The analysis is a ...

  17. Conditionally-Sampled Turbulent and Nonturbulent Measurements of Entropy Generation Rate in the Transition Region of Boundary Layers

    SciTech Connect (OSTI)

    D. M. McEligot; J. R. Wolf; K. P. Nolan; E. J. Walsh; R. J. Volino

    2006-05-01T23:59:59.000Z

    Conditionally-sampled boundary layer data for an accelerating transitional boundary layer have been analyzed to calculate the entropy generation rate in the transition region. By weighing the nondimensional dissipation coefficient for the laminar-conditioned-data and turbulent-conditioned-data with the intermittency factor the average entropy generation rate in the transition region can be determined and hence be compared to the time averaged data and correlations for steady laminar and turbulent flows. It is demonstrated that this method provides, for the first time, an accurate and detailed picture of the entropy generation rate during transition. The data used in this paper have been taken from detailed boundary layer measurements available in the literature. This paper provides, using an intermittency weighted approach, a methodology for predicting entropy generation in a transitional boundary layer.

  18. Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    Robert Popham; Rashid Sunyaev

    2000-04-03T23:59:59.000Z

    We present solutions for the structure of the boundary layer where the accretion disk meets the neutron star, which is expected to be the dominant source of high-energy radiation in low-mass X-ray binaries which contain weakly magnetized accreting neutron stars. We find that the main portion of the boundary layer gas is hot (> ~10^8 K), low in density, radially and vertically extended, and optically thick to scattering but optically thin to absorption. It will produce large X-ray luminosity by Comptonization. Energy is transported inward by viscosity, concentrating the energy dissipation in the dense, optically thick zone close to the stellar surface. We explore the dependence of the boundary layer structure on the mass accretion rate, the rotation rate of the star, the alpha viscosity parameter and the viscosity prescription. Radiation pressure is the dominant source of pressure in the boundary layer; the flux is close to the Eddington limiting flux even for luminosities well below (~0.01 times) L(Edd). At luminosities near L(Edd), the boundary layer expands radially, and has a radial extent larger than one stellar radius. Based on the temperatures and optical depths which characterize the boundary layer, we expect that Comptonization will produce a power-law spectrum at low source luminosities. At high luminosities, a Planckian spectrum will be produced in the dense region where most of the energy is released, and modified by Comptonization as the radiation propagates outward.

  19. An enriched finite element model with q-refinement for radiative boundary layers in glass cooling

    SciTech Connect (OSTI)

    Mohamed, M. Shadi [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Seaid, Mohammed; Trevelyan, Jon [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom)] [School of Engineering and Computing Sciences, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Laghrouche, Omar [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)] [Institute for Infrastructure and Environment, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2014-02-01T23:59:59.000Z

    Radiative cooling in glass manufacturing is simulated using the partition of unity finite element method. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary simplified P{sub 1} approximation for the radiation in non-grey semitransparent media. To integrate the coupled equations in time we consider a linearly implicit scheme in the finite element framework. A class of hyperbolic enrichment functions is proposed to resolve boundary layers near the enclosure walls. Using an industrial electromagnetic spectrum, the proposed method shows an immense reduction in the number of degrees of freedom required to achieve a certain accuracy compared to the conventional h-version finite element method. Furthermore the method shows a stable behaviour in treating the boundary layers which is shown by studying the solution close to the domain boundaries. The time integration choice is essential to implement a q-refinement procedure introduced in the current study. The enrichment is refined with respect to the steepness of the solution gradient near the domain boundary in the first few time steps and is shown to lead to a further significant reduction on top of what is already achieved with the enrichment. The performance of the proposed method is analysed for glass annealing in two enclosures where the simplified P{sub 1} approximation solution with the partition of unity method, the conventional finite element method and the finite difference method are compared to each other and to the full radiative heat transfer as well as the canonical Rosseland model.

  20. Numerical modeling of boundary layer flow under shoaling and breaking waves

    E-Print Network [OSTI]

    Pattipawaej, Olga Catherina

    1998-01-01T23:59:59.000Z

    is governed by the mass conservation equation 0U 0W ? + =0 0x 0" (2. 1) and the boundary layer approximation to the horizontal momentum equation DU 0U?0U 0 I 0U +U ?+ ? iv ? ?&utc& (2. 2) where D 0 0 0 ? = ? + U ? + W ?. Dt 0t 0z 0 (2. 3) In 2. 1 and 2... stresses. Following Kanetkar (1985), the governing equations 2. 11 and 2. 12 can be written to the first order of approximation as (3. 1) = cqql ? + ? cscsql ? ? ? ci? (3. 2) where the value of ci is found to be 0. 054 by setting production equal...

  1. The effect of tangential mass addition on the boundary layer velocity distribution of a flat plate at zero angle of attack

    E-Print Network [OSTI]

    Miller, Edward Peter

    1965-01-01T23:59:59.000Z

    . V . RESULTS AND DISCUSSION 16 18 20 21 24 Boundary Layer Conditions Downstream of Blowing Slot . Boundary Layer Conditions Upstream of Slot Accuracy of Data 24 40 47 VI. CONCLUSIONS AND RECOMMENDATIONS ~ 51 LITERATURE CITED 54 APPENDIX... of u with Distance Downstream of Slot max Velocity Profile of a Boundary Layer in the Presence of a Blowing Jet 32 7 ~ Comparison of Boundaries A, 8, C, in, Present Experiment with that of Carriere and Eichelbrenner's Results 37 Comparison...

  2. icBIE: A Boundary Integral Equation Program for an Ion Channel in Layered Membrane/Electrolyte Media

    E-Print Network [OSTI]

    Cai, Wei

    in this paper. The program uses a layered media Green's function of the P-B equation in order to accurately and Electromagnetics. External routines/libraries: OpenMP (http://openmp.org/wp/) Nature of problem: Electrostatic method: Boundary integral equation method and the layered media Green's function of the Poisson

  3. 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

  4. X-ray and EUV Spectroscopy of the Boundary Layer Emission of Nonmagnetic Cataclysmic Variables

    E-Print Network [OSTI]

    Christopher W. Mauche

    1997-09-11T23:59:59.000Z

    EUVE, ROSAT, and ASCA observations of the boundary layer emission of nonmagnetic cataclysmic variables (CVs) are reviewed. EUVE spectra reveal that the effective temperature of the soft component of high-Mdot nonmagnetic CVs is kT ~ 10-20 eV and that its luminosity is ~ 0.1-0.5 times the accretion disk luminosity. Although the EUV spectra are very complex and belie simple interpretation, the physical conditions of the boundary layer gas are constrained by emission lines of highly ionized Ne, Mg, Si, and Fe. ROSAT and ASCA spectra of the hard component of nonmagnetic CVs are satisfactorily but only phenomenologically described by multi-temperature thermal plasmas, and the constraints imposed on the physical conditions of this gas are limited by the relatively weak and blended lines. It is argued that significant progress in our understanding of the X-ray spectra of nonmagnetic CVs will come with future observations with XMM, AXAF, and Astro-E.

  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. A one-dimensional sectional model to simulate multicomponent aerosol dynamics in the marine boundary layer 1. Model description

    SciTech Connect (OSTI)

    Fitzgerald, J.W.; Hoppel, W.A. [Remote Sensing Division, Naval Research Laboratory, Washington, District of Columbia (United States)] [Remote Sensing Division, Naval Research Laboratory, Washington, District of Columbia (United States); Gelbard, F. [Modeling and Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico (United States)] [Modeling and Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico (United States)

    1998-07-01T23:59:59.000Z

    A one-dimensional, multicomponent sectional model has been developed to simulate the temporal and vertical variations of the aerosol size distribution and composition in the marine boundary layer (MBL). An important aspect of the model is its ability to handle the transport of aerosols in an atmosphere with humidity gradients with no numerical diffusion caused by the swelling and shrinking of the particles as they move through the humidity gradients. This is achieved by rewriting the aerosol general dynamical equation (GDE) in terms of dry radius thus transferring all variations in radius caused by temporal and spatial humidity variations to the rate coefficients appearing in the equations. The model then solves the new GDE in fixed dry size sections, with the humidity dependence of the processes now included in variable coefficients. This procedure also results in correct gradient transport. A limiting assumption is that the particles equilibrate instantaneously with the ambient water vapor. This assumption limits the maximum particle size which can be treated in the model to ambient (wet) radii less than about 30 {mu}m. All processes currently believed to be important in shaping the MBL size distribution are included in the current version of the model. These include generation of sea-salt aerosol at the ocean surface, nucleation of new particles, coagulation, growth due to condensation of gas-phase reaction products, growth due to sulfate formation during cloud processing, precipitation scavenging, surface deposition, turbulent mixing, gravitational settling, and exchange with the free troposphere. Simple gas-phase chemistry which includes the oxidation of dimethylsulfide and SO{sub 2} to sulfate is incorporated in the current version of the model. {copyright} 1998 American Geophysical Union

  7. Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

    E-Print Network [OSTI]

    Lundquist, Katherine Ann

    2010-01-01T23:59:59.000Z

    large-eddy simulations within mesoscale simulations for windEddy Simulation of a Mesoscale Convective Internal Boundary185, 1957. Pielke, R. , Mesoscale Meteorological Modeling,

  8. 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

  9. Turbulent flow over a house in a simulated hurricane boundary layer

    E-Print Network [OSTI]

    Taylor, Zachary; Gurka, Roi; Kopp, Gregory

    2009-01-01T23:59:59.000Z

    Every year hurricanes and other extreme wind storms cause billions of dollars in damage worldwide. For residential construction, such failures are usually associated with roofs, which see the largest aerodynamic loading. However, determining aerodynamic loads on different portions of North American houses is complicated by the lack of clear load paths and non-linear load sharing in wood frame roofs. This problem of fluid-structure interaction requires both wind tunnel testing and full-scale structural testing. A series of wind tunnel tests have been performed on a house in a simulated atmospheric boundary layer (ABL), with the resulting wind-induced pressures applied to the full-scale structure. The ABL was simulated for flow over open country terrain where both velocity and turbulence intensity profiles, as well as spectra, were matched with available full scale measurements for this type of terrain. The first set of measurements was 600 simultaneous surface pressure measurements over the entire house. A key...

  10. Photophoretic contribution to the transport of absorbing particles across combustion gas boundary layers

    SciTech Connect (OSTI)

    Castillo, J.L. (U.N.E.D., Madrid (Spain)); Mackowski, D.W.; Rosner, D.E. (Yale Univ., New Haven, CT (USA))

    1989-01-01T23:59:59.000Z

    Since radiation energy fluxes can be comparable to convective (Fourier) fluxes in large fossil-fuel-fired power stations and furnaces, the authors have examined particle drift (phoresis) induced by nonuniform photon-particle heating in a host gas. The authors analysis of the photophoretic velocity includes the important slipflow regime, and the numerical results show that photophoresis is a significant transport mechanism for micron-sized absorbing particles in high radiative transfer combustion environments, with equivalent photophoretic diffusivities (dimensionless photophoretic velocities) being as large as 10% of the better-known thermophoretic diffusivity (Rosner, 1980, 1985). Since previous experimental results (Rosner and Kim, 1984) demonstrated that thermophoresis causes over a 3-decade increase in particle deposition rates by convective diffusion, clearly, for small, absorbing particles, photophoresis will also be an important contributor to observed deposition rates. Accordingly, they present mass transfer coefficients for particle transport across laminar gaseous boundary layers, including both particle thermophoresis and photophoresis.

  11. Electron distributions observed with Langmuir waves in the plasma sheet boundary layer

    SciTech Connect (OSTI)

    Hwang, Junga [Solar and Space Weather Research Group, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Department of Astronomy and Space Science, University of Science and Technology, Daejeon (Korea, Republic of); Rha, Kicheol [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Seough, Jungjoon [Solar and Space Weather Research Group, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Yoon, Peter H. [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)

    2014-09-15T23:59:59.000Z

    The present paper investigates the Langmuir turbulence driven by counter-streaming electron beams and its plausible association with observed features in the Earth's plasma sheet boundary layer region. A one-dimensional electrostatic particle-in-cell simulation code is employed in order to simulate broadband electrostatic waves with characteristic frequency in the vicinity of the electron plasma frequency ?/?{sub pe}?1.0. The present simulation confirms that the broadband electrostatic waves may indeed be generated by the counter-streaming electron beams. It is also found that the observed feature associated with low energy electrons, namely quasi-symmetric velocity space plateaus, are replicated according to the present simulation. However, the present investigation only partially succeeds in generating the suprathermal tails such that the origin of observed quasi power-law energetic population formation remains outstanding.

  12. Pulsed Plasma with Synchronous Boundary Voltage for Rapid Atomic Layer Etching

    SciTech Connect (OSTI)

    Economou, Demetre J.; Donnelly, Vincent M.

    2014-05-13T23:59:59.000Z

    Atomic Layer ETching (ALET) of a solid with monolayer precision is a critical requirement for advancing nanoscience and nanotechnology. Current plasma etching techniques do not have the level of control or damage-free nature that is needed for patterning delicate sub-20 nm structures. In addition, conventional ALET, based on pulsed gases with long reactant adsorption and purging steps, is very slow. In this work, novel pulsed plasma methods with synchronous substrate and/or “boundary electrode” bias were developed for highly selective, rapid ALET. Pulsed plasma and tailored bias voltage waveforms provided controlled ion energy and narrow energy spread, which are critical for highly selective and damage-free etching. The broad goal of the project was to investigate the plasma science and engineering that will lead to rapid ALET with monolayer precision. A combined experimental-simulation study was employed to achieve this goal.

  13. Coupled Mesoscale-Large-Eddy Modeling of Realistic Stable Boundary Layer Turbulence

    E-Print Network [OSTI]

    Wang, Yao; Manuel, Lance

    2013-01-01T23:59:59.000Z

    Site-specific flow and turbulence information are needed for various practical applications, ranging from aerodynamic/aeroelastic modeling for wind turbine design to optical diffraction calculations. Even though highly desirable, collecting on-site meteorological measurements can be an expensive, time-consuming, and sometimes a challenging task. In this work, we propose a coupled mesoscale-large-eddy modeling framework to synthetically generate site-specific flow and turbulence data. The workhorses behind our framework are a state-of-the-art, open-source atmospheric model called the Weather Research and Forecasting (WRF) model and a tuning-free large-eddy simulation (LES) model. Using this coupled framework, we simulate a nighttime stable boundary layer (SBL) case from the well-known CASES-99 field campaign. One of the unique aspects of this work is the usage of a diverse range of observations for characterization and validation. The coupled models reproduce certain characteristics of observed low-level jets....

  14. 'Maximum' entropy production in self-organized plasma boundary layer: A thermodynamic discussion about turbulent heat transport

    SciTech Connect (OSTI)

    Yoshida, Z. [Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8561 (Japan); Mahajan, S. M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

    2008-03-15T23:59:59.000Z

    A thermodynamic model of a plasma boundary layer, characterized by enhanced temperature contrasts and ''maximum entropy production,'' is proposed. The system shows bifurcation if the heat flux entering through the inner boundary exceeds a critical value. The state with a larger temperature contrast (larger entropy production) sustains a self-organized flow. An inverse cascade of energy is proposed as the underlying physical mechanism for the realization of such a heat engine.

  15. A study of low-level wind and temperature profiles as a function of stability in the surface boundary layer

    E-Print Network [OSTI]

    Williams, Morgan Glenn

    1970-01-01T23:59:59.000Z

    A STUDY OF LOW-LEVEL WIND AND TEMPERATURE PROFILES AS A FUNCTION OF STABILITY IN THE SURFACE BOUNDARY LAYER A Thesis By Morgan Glenn Williams Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... and content by: . . jy ~( (Chairman of Committee) (lread of Dep. ent) ', ea'ocr) ~!A|I)~ Decemb. r 19 70 ABSTRACT A Study of I. ow-Level Wind and Temperature Profiles as a Function of Stability in the Surface Boundary Layer (December 1970) Morgan...

  16. Formation of Pillars at the Boundaries between HII Regions and Molecular Clouds

    SciTech Connect (OSTI)

    Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H

    2006-04-20T23:59:59.000Z

    We investigate numerically the hydrodynamic instability of an ionization front (IF) accelerating into a molecular cloud, with imposed initial perturbations of different amplitudes. When the initial amplitude is small, the imposed perturbation is completely stabilized and does not grow. When the initial perturbation amplitude is large enough, roughly the ratio of the initial amplitude to wavelength is greater than 0.02, portions of the IF temporarily separate from the molecular cloud surface, locally decreasing the ablation pressure. This causes the appearance of a large, warm HI region and triggers nonlinear dynamics of the IF. The local difference of the ablation pressure and acceleration enhances the appearance and growth of a multimode perturbation. The stabilization usually seen at the IF in the linear regimes does not work due to the mismatch of the modes of the perturbations at the cloud surface and in density in HII region above the cloud surface. Molecular pillars are observed in the late stages of the large amplitude perturbation case. The velocity gradient in the pillars is in reasonably good agreement with that observed in the Eagle Nebula. The initial perturbation is imposed in three different ways: in density, in incident photon number flux, and in the surface shape. All cases show both stabilization for a small initial perturbation and large growth of the second harmonic by increasing amplitude of the initial perturbation above a critical value.

  17. Acidbase chemical reaction model for nucleation rates in the polluted atmospheric boundary layer

    E-Print Network [OSTI]

    June 18, 2012) Climate models show that particles formed by nucleation can affect cloud cover and, therefore, the earth's radiation budget. Measurements worldwide show that nucleation rates in the atmo be a significant source of condensation nuclei (2) and cloud condensation nuclei (CCN) (3). The cloud albedo effect

  18. OBSERVATIONS AND PARAMETERIZATION OF BOUNDARY LAYER STRUCTURES AND CLOUDS AT THE ARM TWP NAURU SITE

    E-Print Network [OSTI]

    .S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United-time winds observed at Nauru are very steady from the East during the entire observing period. An excellent of the island) from satellite estimates and the temperature, moisture, and wind observations from the Nauru site

  19. Posters Triggering of Boundary Layer Cumulus Clouds Over a Heterogeneous Surface

    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's Possible forPortsmouth/Paducah Project Office PressPostdoctoraldecadal observations71971173137355

  20. Local Correlations and Multi-Fractal Behaviour in Marine Boundary Layer Cloud Dynamics

    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 82981-1cnHigh SchoolIn12electron 9 5Let usNucleartearing mode flows andPress) |Local

  1. Simulation of Post-Frontal Boundary Layers Observed During the ARM 2000 Cloud IOP

    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 Secretary Moniz9Morgan McCorkle Communications andin

  2. Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to

    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 Secretary Moniz is TakingDepartmentSensitivities of SCMs to

  3. Wind profile above the surface boundary layer S.-E. Gryning (1), E. Batchvarova (2) and B. Brmmer (3)

    E-Print Network [OSTI]

    Wind profile above the surface boundary layer S.-E. Gryning (1), E. Batchvarova (2) and B. Brümmer in predictions of the wind profile in the lowest hundreds me- ters of the atmosphere, being connected to the general increase in height of structures such as bridges, high houses and wind turbines. The hub height

  4. Evolution and lifetimes of flow topology in a turbulent boundary layer G. E. Elsinga and I. Marusic

    E-Print Network [OSTI]

    Marusic, Ivan

    -similar forms of fluid flow and heat-mass transfer in turbulent boundary layer flow of a nanofluid Phys. Fluids that are coherent in time and space, commonly referred to as eddies or coherent structures.1 They are fundamental remain regarding the dynamics and time scales of these coherent motions. In this study we provide a first

  5. Boundary-Layer Meteorol (2009) 132:129149 DOI 10.1007/s10546-009-9380-8

    E-Print Network [OSTI]

    Porté-Agel, Fernando

    2009-01-01T23:59:59.000Z

    deficit and the turbulence intensity, which are important factors affecting turbine power generation by Vermeer et al. (2003). Detailed understanding of the turbulent properties of turbine wakes under different-Tunnel Investigation of Wind-Turbine Wakes: Boundary-Layer Turbulence Effects Leonardo P. Chamorro · Fernando Porté

  6. DOI 10.1007/s10546-005-9005-9 Boundary-Layer Meteorology (2006) 119: 135157 Springer 2006

    E-Print Network [OSTI]

    and to the thermal internal boundary-layer formation. The strong coastal and orographic influences sensing systems such as lidars use aerosols as tracers, with the optical power measured by a lidar proportional to the aerosol content of the atmosphere. The lidar signal shows strong backscattering within

  7. DOI 10.1007/s10546-005-7772-y Boundary-Layer Meteorology (2006) 118: 477501 Springer 2006

    E-Print Network [OSTI]

    Ribes, Aurélien

    2006-01-01T23:59:59.000Z

    radial velocity measurements on a 6-km radius area in the lowest 3 km of the troposphere. Thus the urban effects appear to be negligible. Keywords: Atmospheric boundary layer, Doppler lidar, Numerical the Marseille area are compared to the Doppler lidar data, for which the spatial res- olution is comparable

  8. Nature of the Mesoscale Boundary Layer Height and Water Vapor Variability Observed 14 June 2002 during the IHOP_2002 Campaign

    E-Print Network [OSTI]

    Guichard, Francoise

    Nature of the Mesoscale Boundary Layer Height and Water Vapor Variability Observed 14 June 2002, Boulder, Colorado (Manuscript received 4 September 2007, in final form 23 June 2008) ABSTRACT Mesoscale at the mesoscale, with the spatial pattern and the magnitude of the variability changing from day to day. On 14

  9. Two-equation model computations of high-speed (ma=2.25, 7.2), turbulent boundary layers

    E-Print Network [OSTI]

    Arasanipalai, Sriram Sharan

    2009-05-15T23:59:59.000Z

    of the Boussinesq coefficient (Cu) and turbulenttransport coefficients (sigmak; sigmaE; sigma; sigma*) on the boundary layer ow is examined. Further,the performance of a new model with realizability-based correction to Cu and corresponding modifications to sigma...

  10. Boundary-Layer Meteorol (2010) 134:157180 DOI 10.1007/s10546-009-9433-z

    E-Print Network [OSTI]

    Gentine, Pierre

    2010-01-01T23:59:59.000Z

    forcing is dependent on the heat storage and diffusion as well as on the coupling of the soil of surface state variables to the frequency of the forcing is analyzed. Keywords Diurnal cycle · Ground heat cycle of temperature and heat-flux profiles in a coupled land- surface and atmospheric boundary layer

  11. Boundary Layer Convergence Induced by Strong Winds across a Midlatitude THOMAS KILPATRICK, NIKLAS SCHNEIDER, AND BO QIU

    E-Print Network [OSTI]

    Qiu, Bo

    Boundary Layer Convergence Induced by Strong Winds across a Midlatitude SST Front* THOMAS in an idealized, dry, two- dimensional configuration, for winds crossing from cold to warm SST and from warm to cold SST. For strong cross-front winds, O(10 m s21 ), changes in the turbulent mixing and MABL depth

  12. ANGULAR MOMENTUM TRANSPORT BY ACOUSTIC MODES GENERATED IN THE BOUNDARY LAYER. II. MAGNETOHYDRODYNAMIC SIMULATIONS

    SciTech Connect (OSTI)

    Belyaev, Mikhail A.; Rafikov, Roman R.; Stone, James M., E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States)

    2013-06-10T23:59:59.000Z

    We perform global unstratified three-dimensional magnetohydrodynamic simulations of an astrophysical boundary layer (BL)-an interface region between an accretion disk and a weakly magnetized accreting object such as a white dwarf-with the goal of understanding the effects of magnetic field on the BL. We use cylindrical coordinates with an isothermal equation of state and investigate a number of initial field geometries including toroidal, vertical, and vertical with zero net flux. Our initial setup consists of a Keplerian disk attached to a non-rotating star. In a previous work, we found that in hydrodynamical simulations, sound waves excited by shear in the BL were able to efficiently transport angular momentum and drive mass accretion onto the star. Here we confirm that in MHD simulations, waves serve as an efficient means of angular momentum transport in the vicinity of the BL, despite the magnetorotational instability (MRI) operating in the disk. In particular, the angular momentum current due to waves is at times larger than the angular momentum current due to MRI. Our results suggest that angular momentum transport in the BL and its vicinity is a global phenomenon occurring through dissipation of waves and shocks. This point of view is quite different from the standard picture of transport by a local anomalous turbulent viscosity. In addition to angular momentum transport, we also study magnetic field amplification within the BL. We find that the field is indeed amplified in the BL, but only by a factor of a few, and remains subthermal.

  13. Stability and Turbulence in the Atmospheric Boundary Layer: A Comparison of Remote Sensing and Tower Observations

    SciTech Connect (OSTI)

    Friedrich, K.; Lundquist, J. K.; Aitken, M.; Kalina, E. A.; Marshall, R. F.

    2012-01-01T23:59:59.000Z

    When monitoring winds and atmospheric stability for wind energy applications, remote sensing instruments present some advantages to in-situ instrumentation such as larger vertical extent, in some cases easy installation and maintenance, measurements of vertical humidity profiles throughout the boundary layer, and no restrictions on prevailing wind directions. In this study, we compare remote sensing devices, Windcube lidar and microwave radiometer, to meteorological in-situ tower measurements to demonstrate the accuracy of these measurements and to assess the utility of the remote sensing instruments in overcoming tower limitations. We compare temperature and wind observations, as well as calculations of Brunt-Vaisala frequency and Richardson numbers for the instrument deployment period in May-June 2011 at the U.S. Department of Energy National Renewable Energy Laboratory's National Wind Technology Center near Boulder, Colorado. The study reveals that a lidar and radiometer measure wind and temperature with the same accuracy as tower instruments, while also providing advantages for monitoring stability and turbulence. We demonstrate that the atmospheric stability is determined more accurately when the liquid-water mixing ratio derived from the vertical humidity profile is considered under moist-adiabatic conditions.

  14. Retrieval of Urban Boundary Layer Structures from Doppler Lidar Data. Part I: Accuracy Assessment

    SciTech Connect (OSTI)

    Xia, Quanxin; Lin, Ching Long; Calhoun, Ron; Newsom, Rob K.

    2008-01-01T23:59:59.000Z

    Two coherent Doppler lidars from the US Army Research Laboratory (ARL) and Arizona State University (ASU) were deployed in the Joint Urban 2003 atmospheric dispersion field experiment (JU2003) held in Oklahoma City. The dual lidar data are used to evaluate the accuracy of the four-dimensional variational data assimilation (4DVAR) method and identify the coherent flow structures in the urban boundary layer. The objectives of the study are three-fold. The first objective is to examine the effect of eddy viscosity models on the quality of retrieved velocity data. The second objective is to determine the fidelity of single-lidar 4DVAR and evaluate the difference between single- and dual-lidar retrievals. The third objective is to correlate the retrieved flow structures with the ground building data. It is found that the approach of treating eddy viscosity as part of control variables yields better results than the approach of prescribing viscosity. The ARL single-lidar 4DVAR is able to retrieve radial velocity fields with an accuracy of 98% in the along-beam direction and 80-90% in the cross-beam direction. For the dual-lidar 4DVAR, the accuracy of retrieved radial velocity in the ARL cross-beam direction improves to 90-94%. By using the dual-lidar retrieved data as a reference, the single-lidar 4DVAR is able to recover fluctuating velocity fields with 70-80% accuracy in the along-beam direction and 60-70% accuracy in the cross-beam direction. Large-scale convective roll structures are found in the vicinity of downtown airpark and parks. Vortical structures are identified near the business district. Strong updrafts and downdrafts are also found above a cluster of restaurants.

  15. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOE Patents [OSTI]

    Farrington, Robert B. (Golden, CO); Anderson, Ren (Broomfield, CO)

    2001-01-01T23:59:59.000Z

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  16. MOMENTUM AND THERMAL BOUNDARY-LAYER THICKNESS IN A STAGNATION FLOW CHEMICAL VAPOR DEPOSITION REACTOR

    E-Print Network [OSTI]

    Dandy, David

    REACTOR DAVID S. DANDY AND JUNGHEUM YUN Department of Chemical Engineering Colorado State University Fort deposition pedestal reactors. Expressions for the velocity and temperature profiles within the boundary

  17. MEMS Pressure Sensor Array for Aeroacoustic Analysis of the Turbulent Boundary Layer

    E-Print Network [OSTI]

    White, Robert D.

    holes Density of air c Speed of sound µ Viscosity of air 1 Density of diaphragm (Polysilicon) E1 Modulus of elasticity of diaphragm 1 Poisson's ratio of diaphragm t2 Thickness of Parylene-C layer 2 Density of Parylene-C layer E2 Modulus of elasticity of Parylene-C layer Research Assistant, Department

  18. Friction of a slider on a granular layer: Non-monotonic thickness dependence and effect of boundary conditions

    E-Print Network [OSTI]

    Saloome Siavoshi; Ashish V. Orpe; Arshad Kudrolli

    2005-12-22T23:59:59.000Z

    We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value which depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the grains with fluorescence imaging in a regime where the liquid has no significant effect on the measured friction. The shear profiles obtained as a function of depth show decrease in slip near the sliding surface as the layer thickness is increased. We propose that the friction depends on the degree of grain confinement relative to the sliding surfaces.

  19. Cloud properties and associated radiative heating rates in the tropical western Pacific

    E-Print Network [OSTI]

    Cloud properties and associated radiative heating rates in the tropical western Pacific James H set of atmospheric remote sensing instruments at sites around the world, including three radiative fluxes and heating rates. Maxima in cloud occurrence are found in the boundary layer and the upper

  20. Hygroscopic growth of submicron and supermicron aerosols in the marine boundary layer

    E-Print Network [OSTI]

    balance and climate directly through absorption and scattering of the incoming solar radiation and indirectly through modification of cloud properties [Intergovernmental Panel on Climate Change, 2007 behaviors of the dynamic and complex atmospheric aerosol consisting of particles with a wide range of sizes

  1. Seismic and gravitational studies of melting in the mantle's thermal boundary layers

    E-Print Network [OSTI]

    Van Ark, Emily M

    2007-01-01T23:59:59.000Z

    This thesis presents three studies which apply geophysical tools to the task of better understanding mantle melting phenomena at the upper and lower boundaries of the mantle. The first study uses seafloor bathymetry and ...

  2. The Effects of Step Excrescences on Swept-Wing Boundary-Layer Transition

    E-Print Network [OSTI]

    Duncan, Jr., Glen T.

    2014-08-12T23:59:59.000Z

    flutter and handling-quality clearance flight proved the new test article is safe for the flight-testing experiments. Pressure measurements are compared with computational results, infrared thermography is used to globally detect boundary...

  3. Establishment of a research facility for investigating the effects of unsteady inlet flow, pressure gradient and curvature on boundary layer development, wake development and heat transfer

    E-Print Network [OSTI]

    Pardivala, Darayus Noshir

    1991-01-01T23:59:59.000Z

    ESTABLISHMENT OF A RESEARCH FACILITY FOR INVESTIGATING THE EFFECTS OF UNSTEADY INLET FLOW) PRESSURE GRADIENT AND CURVATURE ON BOUNDARY LAYER DEVELOPMENT) %'AKE DEVELOPMENT AND HEAT TRANSFER A Thesis by DARAYUS NOSHIR PARDIVALA Submitted... THE EFFECTS OF UNSTEADY INLET FLOW, PRESSURE GRADIENT AND CURVATURE ON BOUNDARY LAYER DEVELOPMENT, WAKE DEVELOPMENT AND HEAT TRANSFER A Thesis by DARAYUS NOSHIR PARDIVALA Approved as to style and content by: Taher Schobeiri (Chair of Committee) Gerald...

  4. On the use of a nascent delta function in radiative-transfer calculations for multi-layer media subject to Fresnel boundary

    E-Print Network [OSTI]

    Siewert, Charles E.

    subject to Fresnel boundary and interface conditions R.D.M. Garcia a,Ã, C.E. Siewert b a Instituto de: Radiative transfer Nascent delta function Fresnel conditions Discrete-ordinates method a b s t r a c in a plane-parallel, multi-layer medium subject to Fresnel boundary and interface conditions. As a result

  5. 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.

  6. MEMS Pressure Sensor Array for Aeroacoustic Analysis of the Turbulent Boundary Layer

    E-Print Network [OSTI]

    White, Robert D.

    vent holes Cc Center­to­center spacing of vent holes Density of air c Speed of sound µ Viscosity of air 1 Density of diaphragm (Polysilicon) E1 Modulus of elasticity of diaphragm 1 Poisson's ratio Density of Parylene-C layer E2 Modulus of elasticity of Parylene-C layer 2 Poisson's ratio of Parylene

  7. 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.

  8. On the thermodynamic boundary conditions of a solidifying mushy layer with outflow

    E-Print Network [OSTI]

    Rees Jones, David W.; Worster, M. Grae

    2014-11-27T23:59:59.000Z

    –207. Thermodynamic boundary conditions with outflow 11 Beckermann, C. & Wang, C.Y. 1995 Multiphase/-scale modeling of alloy solidification. In Annual Reviews of Heat Transfer (ed. C. L. Tien), vol. 6, pp. 115–198. Begell House. Conroy, D. & Worster, M. G. 2006 Mush...

  9. Use of shear-stress-sensitive, temperature-insensitive liquid crystals for hypersonic boundary-layer transition detection

    SciTech Connect (OSTI)

    Aeschliman, D.P.; Croll, R.H.; Kuntz, D.W.

    1997-04-01T23:59:59.000Z

    The use of shear-stress-sensitive, temperature-insensitive (SSS/TI) liquid crystals (LCs) has been evaluated as a boundary-layer transition detection technique for hypersonic flows. Experiments were conducted at Mach 8 in the Sandia National Laboratories Hypersonic Wind Tunnel using a flat plate model at near zero-degree angle of attack over the freestream unit Reynolds number range 1.2-5.8x10{sup 6}/ft. Standard 35mm color photography and Super VHS color video were used to record LC color changes due to varying surface shear stress during the transition process for a range of commercial SSS liquid crystals. Visual transition data were compared to an established method using calorimetric surface heat-transfer measurements to evaluate the LC technique. It is concluded that the use of SSS/TI LCs can be an inexpensive, safe, and easy to use boundary-layer transition detection method for hypersonic flows. However, a valid interpretation of the visual records requires careful attention to illumination intensity levels and uniformity, lighting and viewing angles, some prior understanding of the general character of the flow, and the selection of the appropriate liquid crystal for the particular flow conditions.

  10. Wake Turbulence of Two NREL 5-MW Wind Turbines Immersed in a Neutral Atmospheric Boundary-Layer Flow

    E-Print Network [OSTI]

    Bashioum, Jessica L; Schmitz, Sven; Duque, Earl P N

    2013-01-01T23:59:59.000Z

    The fluid dynamics video considers an array of two NREL 5-MW turbines separated by seven rotor diameters in a neutral atmospheric boundary layer (ABL). The neutral atmospheric boundary-layer flow data were obtained from a precursor ABL simulation using a Large-Eddy Simulation (LES) framework within OpenFOAM. The mean wind speed at hub height is 8m/s, and the surface roughness is 0.2m. The actuator line method (ALM) is used to model the wind turbine blades by means of body forces added to the momentum equation. The fluid dynamics video shows the root and tip vortices emanating from the blades from various viewpoints. The vortices become unstable and break down into large-scale turbulent structures. As the wakes of the wind turbines advect further downstream, smaller-scale turbulence is generated. It is apparent that vortices generated by the blades of the downstream wind turbine break down faster due to increased turbulence levels generated by the wake of the upstream wind turbine.

  11. A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer

    SciTech Connect (OSTI)

    Mak, J. E.; Su, L.; Guenther, Alex B.; Karl, Thomas G.

    2013-10-16T23:59:59.000Z

    The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary 5 layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/800 OD tube 150m in length. The inlet ram air pressure is used to flow sampled air through the 10 tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect 15 from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  12. Modeling feedbacks between a boreal forest and the planetary boundary layer

    E-Print Network [OSTI]

    observations at the stand scale (e.g., flux towers) and those at larger scales, e.g., airborne or satellite on the atmospheric surface layer by 21% for latent energy, 64% for air temperature, and 44% for water mixing ratio to the biosphere through the surface energy balance. The response of the terrestrial biosphere to climate

  13. The Effects of Step Excrescences on Swept-Wing Boundary-Layer Transition 

    E-Print Network [OSTI]

    Duncan, Jr., Glen T.

    2014-08-12T23:59:59.000Z

    of an unswept model of similar 2-D pressure gradient. The crossflow instability is believed to dominate the transition process up to the critical step height, while the shear-layer instability dominates after the critical step height. The critical step height...

  14. Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions

    E-Print Network [OSTI]

    T. S. Wood; M. E. McIntyre

    2007-09-10T23:59:59.000Z

    High-latitude laminar confinement of the Sun's interior magnetic field is shown to be possible, as originally proposed by Gough and McIntyre (1998) but contrary to a recent claim by Brun and Zahn (A&A 2006). Mean downwelling as weak as 2x10^-6cm/s -- gyroscopically pumped by turbulent stresses in the overlying convection zone and/or tachocline -- can hold the field in advective-diffusive balance within a confinement layer of thickness scale ~ 1.5Mm ~ 0.002 x (solar radius) while transmitting a retrograde torque to the Ferraro-constrained interior. The confinement layer sits at the base of the high-latitude tachocline, near the top of the radiative envelope and just above the `tachopause' marking the top of the helium settling layer. A family of exact, laminar, frictionless, axisymmetric confinement-layer solutions is obtained for uniform downwelling in the limit of strong rotation and stratification. A scale analysis shows that the flow is dynamically stable and the assumption of laminar flow realistic. The solution remains valid for downwelling values of the order of 10^-5cm/s but not much larger. This suggests that the confinement layer may be unable to accept a much larger mass throughput. Such a restriction would imply an upper limit on possible internal field strengths, perhaps of the order of hundreds of gauss, and would have implications also for ventilation and lithium burning. The solutions have interesting chirality properties not mentioned in the paper owing to space restrictions, but described at http://www.atmos-dynamics.damtp.cam.ac.uk/people/mem/papers/SQBO/solarfigure.html

  15. Boundary Layer The U.S. Department of Energy's Atmospheric Radiation

    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 Materials Find FindRewindParticleBorn on anJeffersonBound Boundary

  16. Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging

    E-Print Network [OSTI]

    R. Capozza; A. Vanossi; A. Benassi; E. Tosatti

    2014-12-22T23:59:59.000Z

    Electrical charging of parallel plates confining a model ionic liquid down to nanoscale distances yields a variety of charge-induced changes in the structural features of the confined film. That includes even-odd switching of the structural layering and charging-induced solidification and melting, with important changes of local ordering between and within layers, and of squeezout behavior. By means of molecular dynamics simulations, we explore this variety of phenomena in the simplest charged Lennard-Jones coarse-grained model including or excluding the effect a neutral tail giving an anisotropic shape to one of the model ions. Using these models and open conditions permitting the flow of ions in and out of the interplate gap, we simulate the liquid squeezout to obtain the distance dependent structure and forces between the plates during their adiabatic appraoch under load. Simulations at fixed applied force illustrate an effective electrical pumping of the ionic liquid, from a thick nearly solid film that withstands the interplate pressure for high plate charge to complete squeezout following melting near zero charge. Effective enthalpy curves obtained by integration of interplate forces versus distance show the local minima that correspond to layering, and predict the switching between one minimum and another under squeezing and charging.

  17. 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.

  18. 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

  19. Stress concentration near stiff inclusions: validation of rigid inclusion model and boundary layers by means of photoelasticity

    E-Print Network [OSTI]

    Diego Misseroni; Francesco Dal Corso; Summer Shahzad; Davide Bigoni

    2014-04-03T23:59:59.000Z

    Photoelasticity is employed to investigate the stress state near stiff rectangular and rhombohedral inclusions embedded in a 'soft' elastic plate. Results show that the singular stress field predicted by the linear elastic solution for the rigid inclusion model can be generated in reality, with great accuracy, within a material. In particular, experiments: (i.) agree with the fact that the singularity is lower for obtuse than for acute inclusion angles; (ii.) show that the singularity is stronger in Mode II than in Mode I (differently from a notch); (iii.) validate the model of rigid quadrilateral inclusion; (iv.) for thin inclusions, show the presence of boundary layers deeply influencing the stress field, so that the limit case of rigid line inclusion is obtained in strong dependence on the inclusion's shape. The introduced experimental methodology opens the possibility of enhancing the design of thin reinforcements and of analyzing complex situations involving interaction between inclusions and defects.

  20. Ice at the Interface: Atmosphere-Ice-Ocean Boundary Layer Processes and Their Role in Polar Change---Workshop Report

    SciTech Connect (OSTI)

    Hunke, Elizabeth C. [Los Alamos National Laboratory

    2012-07-23T23:59:59.000Z

    The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.

  1. Influence of surface heating on the boundary layer stability of flows with favorable pressure gradients

    E-Print Network [OSTI]

    Landrum, David Brian

    1986-01-01T23:59:59.000Z

    $ of its chord heated to about 1. 5 times the adiabatic temperature. Compared to the adiabatic case, the nose heating slightly delayed the initial amplification of disturbances and significantly incr eased the transition length. A vertical traverse... . . . . 10 Fig. 3 Neutral stability cur ve f' or a typical boundar y layer velocity profile 13 Fig. 4a Falkner-Skan velocity profiles with wall heating, 8 0. 0 18 Fig. 4b Falkner-Skan temperature profiles, B=O. O 19 Fig. 5a Falkner-Skan velocity prof...

  2. An investigation of the diabatic wind profile in the atmospheric boundary layer

    E-Print Network [OSTI]

    O'Brien, James Joseph

    1964-01-01T23:59:59.000Z

    in the study; in particular, thanks are extended to Mr. B. Jesse Eckalkamp for his assistance, Mrs. Linda Alexander for typing the final copy, and Mrs. Maxine Pulaski for drafting the figures. The National Space and Aeronautics Administration must...; and the potential temperature at the surface, 8 . After M & 0, the scale 0 length is derived from these quantities by letting Ue be used in place of r /o and H/pc be used in the place of H. since 8 varies little 0 P in the layer concerned, it may be regarded as a...

  3. CHASER proposes to revolutionize our understanding of the interactions of aerosols with clouds by making the first global survey of the fundamental physical entity linking them

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    understanding of weather and climate. The Intergovernmental Panel on Climate Change (IPCC) and the Decadal of the boundary layer air) simultaneously, allowing their effects to be distinguished. Changes in the behavior cloud solar reflectance for a constant liquid water path (Twomey 1977) if the clouds are not optically

  4. Boundary layer (shear-band) in frustrated viscoplastic flows T. CHEVALIER, S. RODTS, X. CHATEAU, J. BOUJLEL, M. MAILLARD, P. COUSSOT

    E-Print Network [OSTI]

    Boyer, Edmond

    (paints, mortars, concrete, drilling fluids) in food industry and cooking (purees, sauces, dough stress fluids give rise to a boundary layer, which takes the form of a liquid region of uniform stress fluids such as concentrated colloids, emul- sions, foams, are jammed systems which behave as liq

  5. TRANSPORT OF HEAT, WATER VAPOR AND CARBON DOXIDE BY LONG PERIOD EDDIES IN THE STABLE BOUNDARY LAYER

    SciTech Connect (OSTI)

    Kurzeja, R.

    2010-07-26T23:59:59.000Z

    The vertical transport of heat and trace chemicals for a night in April has been studied with a wavelet analysis and conventional one-hour averages. It was found that for the night of April 20, 2009, turbulent kinetic energy, heat and trace chemicals were transported directed downward from the jet core. The most significant periods for this transport were less than 5 minutes and greater than one hour with intermittent transport taking place in the 5 min to 1 hour time frame. The nocturnal boundary layer is characterized by turbulent intermittency, long period oscillations, and a slow approach to equilibrium, (Mahrt, 1999). Although turbulence is usually maintained by surface friction, downward transport from low-level jets can also play an important role in turbulence maintenance and in the transport of scalars, Mahrt (1999), Banta et al. (2006). The eddy covariance flux measurement technique assumes continuous turbulence which is unusual in the stable boundary because significant flux transport occurs via turbulent eddies whose periods are long compared with the averaging time (Goulden et al., 1996). Systematic error in eddy flux measurements is attributed mainly to the neglect of long period eddies. Banta et al. (2006) noted that observations of turbulence below the low level jet suggested that while upward transport of turbulence kinetic energy (TKE) is common, downward transport from the jet can also occur. They found that in the CASES 99 experiments that turbulence scaled well with the strength of the low-level jet, and that surface cooling was more important than surface roughness. Because nocturnal turbulence is intermittent and non-stationary, the appropriate averaging time for calculation of TKE and EC fluxes is not obvious. Wavelet analysis is, thus, a more suitable analysis tool than conventional Fourier analysis.

  6. Horizontal-Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Yelena L.; Banta, Robert M.; Kelley, Neil D.; Jonkman, Bonnie J.; Tucker, Sara C.; Newsom, Rob K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--has been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA’s High Resolution Doppler Lidar (HRDL), which have been shown to be numerically equivalent to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance ?u2 were computed from HRDL measurements of the line-of-sight (LOS) velocity using a technique described in Banta, et al. (2002). The technique was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. It then describes several series of averaging tests that produced the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal velocity variance ?u2. The results show high correlation (0.71-0.97) of the mean U and average wind speed measured by sodar and in-situ instruments, independent of sampling strategies and averaging procedures. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging techniques.

  7. Dynamics and energetics of the cloudy boundary layer in simulations of off-ice flow in the marginal ice zone

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    kinetic energy even in the present case where very strong surface heat fluxes occur. Ice-phase. Inclusion of the ice phase significantly affected the radiative budget as compared to purely liquid clouds, illustrating the importance of ice-phase­radiative couplings for accurate simulations of arctic clouds

  8. Boundary Layer Lubrication

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

    refinement of scuffing model to include all classes of materials, especially ceramics and thin-film coatings. Redesign and refine the x-ray accessible tribometer for in-situ study...

  9. Boundary-Layer Meteorol (2012) 143:324 DOI 10.1007/s10546-011-9674-5

    E-Print Network [OSTI]

    Fairall · Chris Williams · Tom Ayers · Alan Brewer · Simon P. de Szoeke · Virendra Ghate Received: 9 and their influence on radiative processes (Stephens et al. 1990). Shipboard cloud studies over the ocean off

  10. Mars Exploration Rover (MER) Panoramic Camera (Pancam) Twilight Image Analysis for Determination of Planetary Boundary Layer and Dust Particle Size Parameters

    E-Print Network [OSTI]

    Grounds, Stephanie Beth

    2012-02-14T23:59:59.000Z

    to take surface-based measurements to offer support for dust and boundary layer measurements made from remote sensors (Lemmon et al., 2004a). Mars has different atmospheric characteristics from those on Earth. For example, the solar constant for Mars... is approximately 44% of the value for Earth (varying by approximately 20%), and the temperature ranges on Mars (- 125?C to +25?C) slightly ____________ This thesis follows the style of the Journal of Geophysical Research. 2 overlap those on Earth (- 80?C...

  11. 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.

  12. Nitrogen Oxides in the Nocturnal Boundary Layer: Chemistry of Nitrous Acid (HONO) and the Nitrate Radical (N03)

    SciTech Connect (OSTI)

    Jochen Stutz

    2005-05-24T23:59:59.000Z

    Summary Chemical processes occurring at night in the lowest part of the urban atmosphere, the so called nocturnal boundary layer (NBL), can influence the composition of the atmosphere during the night as well as the following day. They may impact the budgets of some of the most important pollutants, such as ozone and nitrogen oxides, as well as influence size and composition of particular matter. Few studies have thus far concentrated on the nocturnal chemistry of the urban NBL, most likely due to the strong influence of vertical transport and mixing, which requires the measurement of trace gas profiles instead of simple point observations. Motivated by our lack of observations and understanding of nocturnal chemistry, the focus of this project was the study of the vertical distribution of trace gases and the altitude dependence of nocturnal chemistry under polluted conditions through field observations and modeling studies. The analysis of three field experiments (TEXAQS, Houston, 2000; Phoenix Sunrise Ozone Experiment, 2001; NAPOX, Boston, 2002), two of which were performed in this project, showed that ozone concentrations typically increase with height in the lowest 150m, while NO2 typically decreases. NO3, the dominant nocturnal radical species, showed much higher concentrations in the upper part of the NBL, and was often not present at the ground. With the help of a one-dimensional chemical transport model, developed in this project, we found that the interaction of ground emissions of NOx and hydrocarbons, together with their vertical transport, is responsible for the vertical profiles. The dominant chemical reactions influencing ozone, NO2 and NO3 are the reaction of ozone and NO3 with freshly emitted NO. Sensitivity studies with our model showed that the magnitude of the trace gas gradients depend both on the emission rates and the vertical stability of the NBL. Observations and model analysis clearly show that nocturnal chemistry in urban areas is altitude dependent. Measurements at one altitude, for example at the ground, where most air quality monitoring stations are located, are not representative for the rest of the NBL. Our model also revealed that radical chemistry is, in general, altitude dependent at night. We distinguish three regions: an unreactive, NO rich, ground layer; an upper, O3 and NO3 dominated layer, and a reactive mixing layer, where RO2 radicals are mixed from aloft with NO from the ground. In this reactive layer an active radical chemistry and elevated OH radical levels can be found. The downward transport of N2O5 and HO2NO2, followed by their thermal decay, was also identified as a radical source in this layer. Our observations also gave insight into the formation of HONO in the NBL. Based on our field experiments we were able to show that the NO2 to HONO conversion was relative humidity dependent. While this fact was well known, we found that it is most likely the uptake of HONO onto surfaces which is R.H. dependent, rather than the NO2 to HONO conversion. This finding led to the proposal of a new NO2 to HONO conversion mechanism, which is based on solid physical chemical principles. Noteworthy is also the observation of enhanced NO2 to HONO conversion during a dust storm event in Phoenix. The final activity in our project investigated the influence of the urban canopy, i.e. building walls and surfaces, on nocturnal chemistry. For the first time the surface area of a city was determined based on a Geographical Information System database of the city of Santa Monica. The surface to volume areas found in this study showed that, in the 2 lower part of the NBL, buildings provide a much larger surface area than the aerosol. In addition, buildings take up a considerable amount of the volume near the ground. The expansion of our model and sensitivity studies based on the Santa Monica data revealed that the surface area of buildings considerably influences HONO levels in urban areas. The volume reduction leads to a decrease of O3 and an increase of NO2 near the ground due to the stronger impact o

  13. Isolating Effects of Water Table Dynamics, Terrain, and Soil Moisture Heterogeneity on the Atmospheric Boundary Layer Using Coupled Models

    E-Print Network [OSTI]

    Rihani, Jehan

    2010-01-01T23:59:59.000Z

    boundary conditions of wind, potential temperature, andvariables such as winds, potential temperature, rainfall,variables such as wind speed, potential temperature, and

  14. Satellite Remote Sensing of Mid-level Clouds

    E-Print Network [OSTI]

    Jin, Hongchun 1980-

    2012-11-07T23:59:59.000Z

    algorithm is evaluated using the CALIPSO cloud phase products for single-layer, heterogeneous, and multi-layer scenes. The AIRS phase algorithm has excellent performance (>90%) in detecting ice clouds compared to the CALIPSO ice clouds. It is capable...

  15. Horizontal Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Y. L.; Banta, R. M.; Kelley, N. D.; Jonkman, B. J.; Tucker, S. C.; Newsom, R. K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--have been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA's high-resolution Doppler lidar (HRDL), which have been shown to be approximately equal to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance {sigma}2u were computed from HRDL measurements of the line-of-sight (LOS) velocity using a method described by Banta et al., which uses an elevation (vertical slice) scanning technique. The method was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. The results for the mean U and mean wind speed measured by sodar and in situ instruments for all nights of LLLJP show high correlation (0.71-0.97), independent of sampling strategies and averaging procedures, and correlation coefficients consistently >0.9 for four high-wind nights, when the low-level jet speeds exceeded 15 m s{sup -1} at some time during the night. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging parameters. Several series of averaging tests are described, to find the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal-velocity variance {sigma}{sup 2}{sub u}. Because of the nonstationarity of the SBL data, the best results were obtained when the velocity data were first averaged over intervals of 1 min, and then further averaged over 3-15 consecutive 1-min intervals, with best results for the 10- and 15-min averaging periods. For these cases, correlation coefficients exceeded 0.9. As a part of the analysis, Eulerian integral time scales ({tau}) were estimated for the four high-wind nights. Time series of {tau} through each night indicated erratic behavior consistent with the nonstationarity. Histograms of {tau} showed a mode at 4-5 s, but frequent occurrences of larger {tau} values, mostly between 10 and 100 s.

  16. Boundary-Layer Meteorol (2010) 134:223242 DOI 10.1007/s10546-009-9440-0

    E-Print Network [OSTI]

    Katul, Gabriel

    2010-01-01T23:59:59.000Z

    ). However, even though longwave radiation effects on an evolving NBL have been the subject of a number-sky conditions, which is the subject here. Atmospheric emissivity varies with cloud cover and concentration emissivity in modelling the radiative properties of the NBL especially for clear-sky conditions. Keywords

  17. The chemistry of OH and HO2 radicals in the boundary layer over the tropical Atlantic Ocean

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    fore passing near to the Canary Islands on its way to Capepassing close to the Canary Islands before approaching CapePolarstern north of the Canary Islands. Significant boundary

  18. Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets

    E-Print Network [OSTI]

    Schlegel, Fabrice

    Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in ...

  19. Measurement of Boundary-Layer Temperature Profiles by a Scanning 5-MM Radiometer During the 1999 Winter NSA/AAO Radiometer Exp

    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 82981-1cnHighand Retrievals from a NewCuneo Matthew1, 20121 H( 7 Be,Boundary-Layer

  20. Jupiter as an exoplanet: UV to NIR transmission spectrum reveals hazes, a Na layer and possibly stratospheric H2O-ice clouds

    E-Print Network [OSTI]

    Montañes-Rodriguez, P; Palle, E; Lopez-Puertas, M; Garcia-Melendo, E

    2015-01-01T23:59:59.000Z

    Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. But the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here we show the UV-VIS-IR transmission spectrum of Jupiter, as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter's shadow i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere, and strong absorption features from CH4. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H2O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore...

  1. Effect of unsteady wake passing frequency on boundary layer transition on the concave surface of a curved plate

    E-Print Network [OSTI]

    Read, Robert Kevin

    1997-01-01T23:59:59.000Z

    frequencies. The periodic unsteady flow is generated utilizing an unsteady flow research facility with a rotating cascade of rods positioned upstream of the curved plate. The inlet velocity is measured using a X-wire hot-film probe while the unsteady boundary...

  2. 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.

  3. Development and testing of an aerosol/stratus cloud parameterization scheme for middle and high latitudes. Year 3 technical progress report, November 1, 1996--August 31, 1997

    SciTech Connect (OSTI)

    Kreidenweis, S.M.; Cotton, W.R.

    1997-09-02T23:59:59.000Z

    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 net radiative forcing of clouds varies strongly with latitude. Poleward of 30 degrees in both hemispheres, low-level clouds create a net cooling effect corresponding to radiative divergences of {minus}50 to {minus}100 W/m{sup 2}. It is likely that a combination of fogs, boundary-layer stratocumulus, and stratus clouds are the main contributors to this forcing. Models of the response of the microphysical and radiative properties of clouds to changes in aerosol abundance, for a variety of large-scale meteorological forcings, are important additions to GCMs used for the study of the role of Arctic systems in global climate. The overall objective of this research is 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 parameterization is to be designed for ultimate use in GCM simulations as a tool in understanding the role of CCN, IN, and Arctic clouds in radiation budgets. Several versions of the CSU RAMS (Regional Atmospheric Modeling System) will be used during the course of this work. The parameterizations developed in this research are intended for application in 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.

  4. Detailed study of the influence of surface misorientation on the density of Anti-Phase Boundaries in 3C-SiC layers grown on (001) silicon

    SciTech Connect (OSTI)

    Jiao, S. [Universite Francois Rabelais, Tours, Laboratoire de Microelectronique de Puissance, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours Cedex 2 (France); Centre de Recherche sur l'Hetero-Epitaxie et ses Applications CNRS-UPR10, rue Bernard Gregory, 06560 Valbonne (France); Zielinski, M.; Chassagne, T. [NOVASiC, Savoie Technolac, Arche Bat 4, BP 267, 73375 Le Bourget du Lac Cedex (France); Roy, S. [Saint Gobain recherche, 39 Quai Lucien Lefranc 93300 Aubervilliers cedex (France); Michaud, J. F.; Alquier, D. [Universite Francois Rabelais, Tours, Laboratoire de Microelectronique de Puissance, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours Cedex 2 (France); Portail, M. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications CNRS-UPR10, rue Bernard Gregory, 06560 Valbonne (France)

    2010-11-01T23:59:59.000Z

    In this work we investigated the influence of the Si substrate misorientation and 3C-SiC film thickness on the density of Anti-Phase Boundaries, in order to better understand the mechanism of antiphase domain annihilation. The two highlights in our work are the utilization of [001] orientated Si on-axis wafer with spherical dimples, which gave us access to a continuum of off-cut angles (0 deg. to {approx}11 deg.) and directions, and the deposition of elongated silicon islands on the surface of 3C-SiC epilayers, which improved the detection of APDs by analysis of Scanning Electron Microscopy images. We found that for a given layer thickness the relative surface occupation of one domain increases with the off-cut angle value, leading to single domain film up to a certain angle. This critical value is reduced as the film is thickened.

  5. 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.

  6. Interface boundary conditions for dynamic magnetization and spin wave dynamics in a ferromagnetic layer with the interface Dzyaloshinskii-Moriya interaction

    SciTech Connect (OSTI)

    Kostylev, M. [School of Physics, M013, University of Western Australia, Crawley, Perth 6009, Western Australia (Australia)

    2014-06-21T23:59:59.000Z

    In this work, we derive the interface exchange boundary conditions for the classical linear dynamics of magnetization in ferromagnetic layers with the interface Dzyaloshinskii-Moriya interaction (IDMI). We show that IDMI leads to pinning of dynamic magnetization at the interface. An unusual peculiarity of the IDMI-based pinning is that its scales as the spin-wave wave number. We incorporate these boundary conditions into an existing numerical model for the dynamics of the Damon-Eshbach spin wave in ferromagnetic films. IDMI affects the dispersion and the frequency non-reciprocity of the travelling Damon-Eshbach spin wave. For a broad range of film thicknesses L and wave numbers, the results of the numerical simulations of the spin wave dispersion are in a good agreement with a simple analytical expression, which shows that the contribution of IDMI to the dispersion scales as 1/L, similarly to the effect of other types of interfacial anisotropy. Suggestions to experimentalists how to detect the presence of IDMI in a spin wave experiment are given.

  7. 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.

  8. 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.

  9. Polluting of Winter Convective Clouds upon Transition from Ocean Inland Over Central California: Contrasting Case Studies

    SciTech Connect (OSTI)

    Rosenfeld, Daniel; Chemke, Rei; Prather, Kimberly; Suski, Kaitlyn; Comstock, Jennifer M.; Schmid, Beat; Tomlinson, Jason M.; Jonsson, Haf

    2014-01-01T23:59:59.000Z

    In-situ aircraft measurements of aerosol chemical and cloud microphysical properties were conducted during the CalWater campaign in February and March 2011 over the Sierra Nevada Mountains and the coastal waters of central California. The main objective was to elucidate the impacts of aerosol properties on clouds and precipitation forming processes. In order to accomplish this, we compared contrasting cases of clouds that ingested aerosols from different sources. The results showed that clouds containing pristine oceanic air had low cloud drop concentrations and started to develop rain 500 m above their base. This occurred both over the ocean and over the Sierra Nevada, mainly in the early morning when the radiatively cooled stable continental boundary layer was decoupled from the cloud base. Supercooled rain dominated the precipitation that formed in growing convective clouds in the pristine air, up to the -21°C isotherm level. A contrasting situation was documented in the afternoon over the foothills of the Sierra Nevada, when the clouds ingested high pollution aerosol concentrations produced in the Central Valley. This led to slow growth of the cloud drop effective radius with height and suppressed and even prevented the initiation of warm rain while contributing to the development of ice hydrometeors in the form of graupel. Our results show that cloud condensation and ice nuclei were the limiting factors that controlled warm rain and ice processes, respectively, while the unpolluted clouds in the same air mass produced precipitation quite efficiently. These findings provide the motivation for deeper investigations into the nature of the aerosols seeding clouds.

  10. Large Amplitude Spatial and Temporal Gradients in Atmospheric Boundary Layer CO2 Mole Fractions Detected With a Tower-Based Network in the U.S. Upper Midwest

    SciTech Connect (OSTI)

    Miles, Natasha; Richardson, S. J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, A.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

    2012-02-21T23:59:59.000Z

    This study presents observations of atmospheric CO{sub 2} mole fraction from a nine-tower, regional network deployed during the North American Carbon Program's Mid-Continent Intensive during 2007-2009. Within this network in a largely agricultural area, mean atmospheric CO{sub 2} gradients were strongly correlated with both ground-based inventory data and estimates from satellite remote sensing. The average seasonal drawdown for corn-dominated sites (35 ppm) is significantly larger than has been observed at other continental boundary layer sites. Observed growing-season median CO{sub 2} gradients are strongly dependent on local flux. The gradients between cross-vegetation site-pairs, for example, average 2.0 ppm/100 km, four times larger than the similar-vegetation site-pair average. Daily-timescale gradients are as large as 5.5 ppm/100 km, but dominated by advection rather than local flux. Flooding in 2008 led to a region-wide 23 week delay in growing-season minima. The observations show that regional-scale CO{sub 2} mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO{sub 2}.

  11. 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.

  12. Clouds, Aerosols and Precipitation in the Marine Boundary Layer (CAP-MBL) AMF Deployment Graciosa Island, Azores, NE Atlantic Ocean May 2009-December 2010

    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 NationalCommitteeof3 the Marine the

  13. Boundary streaming with Navier boundary condition Jin-Han Xiea)

    E-Print Network [OSTI]

    Vanneste, Jacques

    is the fluid's kinematic shear viscosity and is the wave's angular frequency. In water, and for frequencies applications involving high-frequency acoustic waves over a solid boundary, the Stokes boundary-layer thickness to travelling and standing waves shows that the boundary slip respectively increases and decreases the streaming

  14. 8, 88178846, 2008 Observed boundary-

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 8817­8846, 2008 Observed boundary- layer/mesoscale impacts on Saharan dust J. H. Marsham et and Enviroment, University of Leeds, Leeds, UK 2 Institut f¨ur Meteorologie und Klimaforschung, Universit@env.leeds.ac.uk) 8817 #12;ACPD 8, 8817­8846, 2008 Observed boundary- layer/mesoscale impacts on Saharan dust J. H

  15. An annual cycle of Arctic cloud characteristics observed by radar and lidar at SHEBA

    E-Print Network [OSTI]

    Shupe, Matthew

    distribution of cloud boundary heights, and occurrence of liquid phase in clouds are determined from radar-observed clouds containing liquid was 73% for the year. The least amount of liquid water phase was observed during-detected clouds. Liquid was distributed in a combination of all-liquid and mixed phase clouds, and was detected

  16. A Near-Global Climatology of Single-Layer and Overlapped Clouds and Their Optical Properties Retrieved from Terra/MODIS Data Using a New Algorithm

    E-Print Network [OSTI]

    Li, Zhanqing

    Retrieved from Terra/MODIS Data Using a New Algorithm FU-LUNG CHANG Earth System Science Interdisciplinary Center, University of Maryland, College Park, College Park, Maryland ZHANQING LI Earth System Science) trapping longwave radiation in the earth­atmosphere system. Unlike many low clouds that have a cooling

  17. 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.

  18. Cloud Property Retrieval Products for Graciosa Island, Azores

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

    Dong, Xiquan

    The motivation for developing this product was to use the Dong et al. 1998 method to retrieve cloud microphysical properties, such as cloud droplet effective radius, cloud droplets number concentration, and optical thickness. These retrieved properties have been used to validate the satellite retrieval, and evaluate the climate simulations and reanalyses. We had been using this method to retrieve cloud microphysical properties over ARM SGP and NSA sites. We also modified the method for the AMF at Shouxian, China and some IOPs, e.g. ARM IOP at SGP in March, 2000. The ARSCL data from ARM data archive over the SGP and NSA have been used to determine the cloud boundary and cloud phase. For these ARM permanent sites, the ARSCL data was developed based on MMCR measurements, however, there were no data available at the Azores field campaign. We followed the steps to generate this derived product and also include the MPLCMASK cloud retrievals to determine the most accurate cloud boundaries, including the thin cirrus clouds that WACR may under-detect. We use these as input to retrieve the cloud microphysical properties. Due to the different temporal resolutions of the derived cloud boundary heights product and the cloud properties product, we submit them as two separate netcdf files.

  19. 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.

  20. Temperature inversion on the surface of externally heated optically thick multigrain dust clouds

    E-Print Network [OSTI]

    Dejan Vinkovic

    2006-12-01T23:59:59.000Z

    It was recently discovered that the temperature in the surface layer of externally heated optically thick gray dust clouds increases with the optical depth for some distance from the surface, as opposed to the normal decrease in temperature with distance in the rest of the cloud. This temperature inversion is a result of efficient absorption of diffuse flux from the cloud interior by the surface dust exposed to the external radiation. A micron or bigger size grains experience this effect when the external flux is of stellar spectrum. We explore what happens to the effect when dust is a mixture of grain sizes (multigrain). Two possible boundary conditions are considered: i) a constant external flux without constrains on the dust temperature, and ii) the maximum dust temperature set to the sublimation temperature. We find that the first condition allows small grains to completely suppress the temperature inversion of big grains if the overall opacity is dominated by small grains. The second condition enables big grains to maintain the inversion even when they are a minor contributor to the opacity. In reality, the choice of boundary condition depends on the dust dynamics. When applied to the physics of protoplanetary disks, the temperature inversion leads to a previously unrecognized disk structure where optically thin dust can exist inside the dust destruction radius of an optically thick disk. We conclude that the transition between the dusty disk and the gaseous inner clearing is not a sharp edge, but rather a large optically thin region.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Oscillatory flow across an irregular boundary Geno Pawlak

    E-Print Network [OSTI]

    Pawlak, Geno

    ; KEYWORDS: eddies, tidal mixing, rough boundary, oscillatory flow, residual currents, wave boundary layers 1Oscillatory flow across an irregular boundary Geno Pawlak Department of Ocean and Resources. Introduction [2] Oscillatory flow past a rough boundary is a prevalent feature in a number of oceanographic

  7. 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

  8. Using Doppler spectra to separate hydrometeor populations and analyze ice precipitation in multilayered mixed-phase clouds

    SciTech Connect (OSTI)

    Rambukkange, Mahlon P.; Verlinde, J.; Eloranta, E. W.; Flynn, Connor J.; Clothiaux, Eugene E.

    2011-01-31T23:59:59.000Z

    Multimodality of cloud radar Doppler spectra is used to partition cloud particle phases and to separate distinct ice populations in the radar sample volume, thereby facilitating analysis of individual ice showers in multilayered mixed-phase clouds. A 35-GHz cloud radar located at Barrow, Alaska, during the Mixed-Phase Arctic Cloud Experiment collected the Doppler spectra. Data from a pair of collocated depolarization lidars confirmed the presence of two liquid cloud layers reported in this study. Surprisingly, both of these cloud layers were embedded in ice precipitation yet maintained their liquid. Our spectral separation of the ice precipitation yielded two distinct ice populations: ice initiated within the two liquid cloud layers and ice precipitation formed in higher cloud layers. Comparisons of ice fall velocity versus radar reflectivity relationships derived for distinct showers reveal that a single relationship might not properly represent the ice showers during this period.

  9. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Why are mixed-phase altocumulus clouds poorly predicted by

    E-Print Network [OSTI]

    Hogan, Robin

    ., 2012] means they are a significant contributor to the cloud radiative effect. The liquid layer at cloud et al., 2003] and is effective at reflecting solar radiation in- cident on the cloud. Correctly of radiative transfer. The liquid-over-ice vertical structure of mixed-phase clouds [Hobbs and Rangno, 1985

  10. Boundary layer response to wind gusts

    E-Print Network [OSTI]

    Morland, Bruce Thomas

    1968-01-01T23:59:59.000Z

    . and Mrs. Sruce T'. garland. Ths author took his gachslcr cf Science degree frns Arlington Stats College in lp66. He worked briefly fcr X, lug&secs~ought dircraft in ths airlcads group ior the p g Crusader. While working ca his Meeter ef Science degree...

  11. Convective Instability of a Boundary Layer with

    E-Print Network [OSTI]

    Conrad, Clint

    proportional to the integral over the depth of the lithosphere of the 19 #12;ratio of thermal buoyancy. Such instabilities are driven by the negative thermal buoyancy of the cold lithosphere and retarded largely for driving convective downwelling. For non-Newtonian viscosity with power law exponent n and temperature

  12. Stability of Small Viscosity Noncharacteristic Boundary Layers

    E-Print Network [OSTI]

    Métivier, Guy

    . . . . . . . . . . . . . . . . . . . 17 1.3.2 The mixed Cauchy-problem . . . . . . . . . . . . . . . 17 1.4 BKW expansions

  13. Stability of Small Viscosity Noncharacteristic Boundary Layers

    E-Print Network [OSTI]

    Métivier, Guy

    . . . . . . . . . . . . . . . . . . . 17 1.3.2 The mixed Cauchy­problem . . . . . . . . . . . . . . . 17 1.4 BKW expansions

  14. Thunderstorm influence on boundary layer winds

    E-Print Network [OSTI]

    Schmidt, Jill Marie

    1986-01-01T23:59:59.000Z

    of this research was to develop a conceptual model of selected pre-storm ambient conditions as a function of the strength of a thunderstorm's outflow. The time of maximum rainfall during the thunderstorm in relation to the time of maximum outflow was a... selected for study from well-defined Code 3 cells (thunderstorms). The results indicated that two conceptual models were necessary to describe the pre-storm ambient conditions that led to thunderstorm development and outflow. One model contained...

  15. Boundary Layer Lubrication Mechanisms | 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't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity Concerns inStudy1

  16. Boundary Layer Lubrication Mechanisms | 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't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity Concerns

  17. Boundary Layer Lubrication | 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't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity

  18. Boundary Layer Lubrication | 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't Your Destiny: The FutureCommentsEnergyandapproximatelyBoostingand Capacity2009 DOE Hydrogen

  19. ARM - Measurement - Planetary boundary layer height

    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 for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowband upwelling irradiancenumber concentration

  20. Cloud Computing og availability

    E-Print Network [OSTI]

    Christensen, Henrik Bærbak

    Cloud Computing og availability Projekt i pålidelighed Henrik Lavdal - 20010210 Søren 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

  1. 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 ...

  2. TRACKING DYNAMIC BOUNDARIES BY EVOLVING Tingting Jiang

    E-Print Network [OSTI]

    Tingting Jiang

    range of applications. An example in image processing is the analysis of image sequences taken might track the boundary of a forest fire. Other applications include tracking spills of oil or poisonous gas, or clouds and weather patterns. In this dissertation, the author describes a new tracking

  3. MAE Seminar Series Boundary Closures for

    E-Print Network [OSTI]

    Krovi, Venkat

    ) boundary layer stability and transition. 206 Furnas Hall Thursday, April 8th, 2010 11:00 am ­ 12:00 pmMAE Seminar Series Boundary Closures for ESWENO Schemes Mark H. Carpenter, Ph.D. Computational AeroSciences Branch NASA Langley Research Center Abstract Energy Stable Weighted Essentially Non--Oscillatory (ESWENO

  4. 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

  5. Analysis of the Tropical Tropopause Layer Cirrus in CALIPSO and MLS Data - A Water Perspective

    E-Print Network [OSTI]

    Wang, Tao

    2012-07-16T23:59:59.000Z

    Two mechanisms appear to be primarily responsible for the formation of cirrus clouds in Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. Here we propose to identify TTL cirrus clouds by analyzing...

  6. 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

  7. The GCM Oriented Calipso Cloud Product (CALIPSO-GOCCP) H. Chepfer(1)

    E-Print Network [OSTI]

    Dufresne, Jean-Louis

    ;2 Abstract. This paper presents the GCM-Oriented Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Cloud Product (CALIPSO-GOCCP) designed to evaluate the cloudiness simulated by General the effects of viewing geometry, sensors' sensitivity and vertical overlap of cloud layers. For this purpose

  8. Profiling-as-a-Service in Multi-Tenant Cloud Computing Environments

    E-Print Network [OSTI]

    Zhang, Junshan

    of cloud computing by collaboratively detecting and filtering unwanted traffic towards cloud instances. I networks, e.g., building normal and anomalous network behavior profiles [9], [10], detecting traffic, understand and profile network traffic at multiple layers in the multi-tenant cloud computing environment

  9. Aerosol--cloud drop concentration closure in warm cumulus W. C. Conant,1

    E-Print Network [OSTI]

    Jimenez, Jose-Luis

    layer aerosol's effect on cloud microphysics throughout the lowest 1 km of cloud depth. Onboard the radiation balance and hydrological cycle, they are called indirect effects of aerosol on climate, or 4Aerosol--cloud drop concentration closure in warm cumulus W. C. Conant,1 T. M. VanReken,2 T. A

  10. Estimate of the global distribution of stratiform supercooled liquid water clouds using the LITE lidar

    E-Print Network [OSTI]

    Hogan, Robin

    them to generally have a greater effect on the net radiative fluxes than any ice clouds in the profileEstimate of the global distribution of stratiform supercooled liquid water clouds using the LITE layers that have a much larger radiative impact than ice clouds of the same water content because

  11. ARM Cloud Retrieval Ensemble Data Set (ACRED)

    SciTech Connect (OSTI)

    Zhao, C; Xie, S; Klein, SA; McCoy, R; Comstock, JM; Delanoë, J; Deng, M; Dunn, M; Hogan, RJ; Jensen, MP; Mace, GG; McFarlane, SA; O’Connor, EJ; Protat, A; Shupe, MD; Turner, D; Wang, Z

    2011-09-12T23:59:59.000Z

    This document describes a new Atmospheric Radiation Measurement (ARM) data set, the ARM Cloud Retrieval Ensemble Data Set (ACRED), which is created by assembling nine existing ground-based cloud retrievals of ARM measurements from different cloud retrieval algorithms. The current version of ACRED includes an hourly average of nine ground-based retrievals with vertical resolution of 45 m for 512 layers. The techniques used for the nine cloud retrievals are briefly described in this document. This document also outlines the ACRED data availability, variables, and the nine retrieval products. Technical details about the generation of ACRED, such as the methods used for time average and vertical re-grid, are also provided.

  12. Clouds and the Faint Young Sun Paradox

    E-Print Network [OSTI]

    Goldblatt, Colin

    2011-01-01T23:59:59.000Z

    We investigate the role which clouds could play in resolving the Faint Young Sun Paradox (FYSP). Lower solar luminosity in the past means that less energy was absorbed on Earth (a forcing of -50 Wm-2 during the late Archean), but geological evidence points to the Earth being at least as warm as it is today, with only very occasional glaciations. We perform radiative calculations on a single global mean atmospheric column. We select a nominal set of three layered, randomly overlapping clouds, which are both consistent with observed cloud climatologies and reproduce the observed global mean energy budget of Earth. By varying the fraction, thickness, height and particle size of these clouds we conduct a wide exploration of how changed clouds could affect climate, thus constraining how clouds could contribute to resolving the FYSP. Low clouds reflect sunlight but have little greenhouse effect. Removing them entirely gives a~forcing of +25 Wm-2 whilst more modest reduction in their efficacy gives a forcing of +10 ...

  13. Turn-key Raman lidar for profiling atmospheric water vapor, clouds, and aerosols at the US Southern Great Plains Climate Study Site

    SciTech Connect (OSTI)

    Goldsmith, J.E.M.; Blair, F.H.; Bisson, S.E.

    1997-12-31T23:59:59.000Z

    There are clearly identified scientific requirements for continuous profiling of atmospheric water vapor at the Department of Energy, Atmospheric Radiation Measurement program, Southern Great Plains CART (Cloud and Radiation Testbed) site in northern Oklahoma. Research conducted at several laboratories has demonstrated the suitability of Raman lidar for providing measurements that are an excellent match to those requirements. We have developed and installed a ruggedized Raman lidar system that resides permanently at the CART site, and that is computer automated to eliminate the requirements for operator interaction. In addition to the design goal of profiling water vapor through most of the troposphere during nighttime and through the boundary layer during daytime, the lidar provides quantitative characterizations of aerosols and clouds, including depolarization measurements for particle phase studies.

  14. Anomalous magnetosheath properties during Earth passage of an interplanetary magnetic cloud

    SciTech Connect (OSTI)

    Farrugia, C.J. [Univ. of Malta, Msida (Malta)] [Univ. of Malta, Msida (Malta); Erkaev, N.V. [Russian Academy of Sciences, Krasnoyarsk (Russian Federation)] [Russian Academy of Sciences, Krasnoyarsk (Russian Federation); Burlaga, L.F. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)] [and others] [NASA Goddard Space Flight Center, Greenbelt, MD (United States); and others

    1995-10-01T23:59:59.000Z

    In this work the authors present a model for the behavior of the magnetosheath during the passage of the earth thru an interplanetary magnetic cloud. They study the variation of plasma flow and field values as a result of this encounter. The unique feature of such encounters is that they present substantial changes in the solar wind conditions along the bow shock and magnetopause for periods of 1 to 2 days. The mach number upstream of the bow shock can be as low as 3, compared to normal value of 8 to 10. The mach number and magnetic shear across the magnetopause have a major impact on the magnetosheath properties. The authors use the encounter of January 14-15, 1988, as a basis for their model, and apply ideal MHD equations, by means of a boundary layer technique, to study changes in field and plasma flow patterns.

  15. 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

  16. atmospheric layers: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  17. atmospheric superficial layer: Topics by E-print Network

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

    Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current...

  18. 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

  19. 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

  20. 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 ³delayed² 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.

  1. 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.

  2. 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.

  3. Young stars and clouds in Camelopardalis

    E-Print Network [OSTI]

    V. Straizys; V. Laugalys

    2008-11-18T23:59:59.000Z

    Star formation in the Local spiral arm in the direction of the Galactic longitudes 132--158 deg is reviewed. Recent star-forming activity in this Milky Way direction is evidenced by the presence here of the Cam OB1 association and dense dust and molecular clouds containing H$\\alpha$ emission stars, young irregular variables and infrared stellar objects. The clouds of the Local arm concentrate in two layers at 150-300 pc and at about 900 pc from the Sun. The Perseus arm objects in this direction are at a distance of about 2 kpc.

  4. How do A-train Sensors Intercompare in the Retrieval of Above-Cloud Aerosol Optical Depth? A Case Study-based Assessment

    SciTech Connect (OSTI)

    Jethva, H. T.; Torres, O.; Waquet, F.; Chand, Duli; Hu, Yong X.

    2014-01-16T23:59:59.000Z

    We inter-compare the above-cloud aerosol optical depth (ACAOD) of biomass burning plumes retrieved from different A-train sensors, i.e., MODIS, CALIOP, POLDER, and OMI. These sensors have shown independent capabilities to detect and retrieve aerosol loading above marine boundary layer clouds--a kind of situation often found over the Southeast Atlantic Ocean during dry burning season. A systematic one-to-one comparison reveals that, in general, all passive sensors and CALIOP-based research methods derive comparable ACAOD with differences mostly within 0.2 over homogeneous cloud fields. The 532-nm ACAOD retrieved by CALIOP operational algorithm is largely underestimated; however, it’s 1064-nm AOD when converted to 500 nm shows closer agreement to the passive sensors. Given the different types of sensor measurements processed with different algorithms, the close agreement between them is encouraging. Due to lack of adequate direct measurements above cloud, the validation of satellite-based ACAOD retrievals remains an open challenge. The inter-satellite comparison, however, can be useful for the relative evaluation and consistency check.

  5. A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 slicing

    E-Print Network [OSTI]

    Sheridan, Jennifer

    A comparison of cloud top heights computed from airborne lidar and MAS radiance data using CO2 in assessing the accuracy of the CO2-slicing cloud height algorithm. Infrared measurements of upwelling which included various single- layer and multilayer cloud conditions. Overall, the CO2-slicing method

  6. Finite element analysis of shells with layers

    E-Print Network [OSTI]

    Hiller, Jean-François, 1974-

    2002-01-01T23:59:59.000Z

    It is well established that thin shell structures frequently feature narrow bands of strain concentration and localized displacement irregularities referred to as boundary and internal layers. It is crucial to capture these ...

  7. 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.

  8. 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

  9. 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

  10. The Giant Molecular Cloud Environments of Infrared Dark Clouds

    E-Print Network [OSTI]

    Hernandez, Audra K

    2015-01-01T23:59:59.000Z

    We study the GMC environments surrounding 10 IRDCs, based on 13CO molecular line emission from the Galactic Ring Survey. Using a range of physical scales, we measure the physical properties of the IRDCs and their surrounding molecular material extending out to radii, R, of 30pc. By comparing different methods for defining cloud boundaries and for deriving mass surface densities, Sigma, and velocity dispersions, sigma, we settled on a preferred "CE,tau,G" method of "Connected Extraction" in position-velocity space along with Gaussian fitting to opacity-corrected line profiles for velocity dispersion and mass estimation. We examine how cloud definition affects measurements of the magnitude and direction of line of sight velocity gradients and velocity dispersions, including the associated dependencies on size scale. CE,tau,G-defined IRDCs and GMCs show velocity gradient versus size relations that scale approximately as dv_0/ds~s^(-1/2) and velocity dispersion versus size relations sigma~s^(1/2), which are consi...

  11. 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

  12. 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...

  13. 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.

  14. 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.

  15. 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

  16. 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...

  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. 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

  19. 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

  20. 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

  1. A High Resolution Hydrometer Phase Classifier Based on Analysis of Cloud Radar Doppler Spectra.

    SciTech Connect (OSTI)

    Luke,E.; Kollias, P.

    2007-08-06T23:59:59.000Z

    The lifecycle and radiative properties of clouds are highly sensitive to the phase of their hydrometeors (i.e., liquid or ice). Knowledge of cloud phase is essential for specifying the optical properties of clouds, or else, large errors can be introduced in the calculation of the cloud radiative fluxes. Current parameterizations of cloud water partition in liquid and ice based on temperature are characterized by large uncertainty (Curry et al., 1996; Hobbs and Rangno, 1998; Intriery et al., 2002). This is particularly important in high geographical latitudes and temperature ranges where both liquid droplets and ice crystal phases can exist (mixed-phase cloud). The mixture of phases has a large effect on cloud radiative properties, and the parameterization of mixed-phase clouds has a large impact on climate simulations (e.g., Gregory and Morris, 1996). Furthermore, the presence of both ice and liquid affects the macroscopic properties of clouds, including their propensity to precipitate. Despite their importance, mixed-phase clouds are severely understudied compared to the arguably simpler single-phase clouds. In-situ measurements in mixed-phase clouds are hindered due to aircraft icing, difficulties distinguishing hydrometeor phase, and discrepancies in methods for deriving physical quantities (Wendisch et al. 1996, Lawson et al. 2001). Satellite-based retrievals of cloud phase in high latitudes are often hindered by the highly reflecting ice-covered ground and persistent temperature inversions. From the ground, the retrieval of mixed-phase cloud properties has been the subject of extensive research over the past 20 years using polarization lidars (e.g., Sassen et al. 1990), dual radar wavelengths (e.g., Gosset and Sauvageot 1992; Sekelsky and McIntosh, 1996), and recently radar Doppler spectra (Shupe et al. 2004). Millimeter-wavelength radars have substantially improved our ability to observe non-precipitating clouds (Kollias et al., 2007) due to their excellent sensitivity that enables the detection of thin cloud layers and their ability to penetrate several non-precipitating cloud layers. However, in mixed-phase clouds conditions, the observed Doppler moments are dominated by the highly reflecting ice crystals and thus can not be used to identify the cloud phase. This limits our ability to identify the spatial distribution of cloud phase and our ability to identify the conditions under which mixed-phase clouds form.

  2. 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

  3. At this meeting: Oral presentation: Cloud Properties From (A)ATSR (Caroline Poulsen)

    E-Print Network [OSTI]

    Oxford, University of

    sensors including radars, an infrared and microwave sounder unit, and microwave radiometer integrated vertically over each layer separated by cloud base. This strategy makes it possible to evaluate. Recent progress in satellite sensor technology, exempli- fied by hyperspectral sounders and cloud

  4. 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...

  5. 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

  6. 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

  7. 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

  8. 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

  9. Constructing a Merged Cloud-Precipitation Radar Dataset for Tropical Convective Clouds during the DYNAMO/AMIE Experiment at Addu Atoll

    SciTech Connect (OSTI)

    Feng, Zhe; McFarlane, Sally A.; Schumacher, Courtney; Ellis, Scott; Comstock, Jennifer M.; Bharadwaj, Nitin

    2014-05-16T23:59:59.000Z

    To improve understanding of the convective processes key to the Madden-Julian-Oscillation (MJO) initiation, the Dynamics of the MJO (DYNAMO) and Atmospheric Radiation Measurement MJO Investigation Experiment (AMIE) collected four months of observations from three radars, the S-band Polarization Radar (S-Pol), the C-band Shared Mobile Atmospheric Research & Teaching Radar (SMART-R), and Ka-band Zenith Radar (KAZR) on Addu Atoll in the tropical Indian Ocean. This study compares the measurements from the S-Pol and SMART-R to those from the more sensitive KAZR in order to characterize the hydrometeor detection capabilities of the two scanning precipitation radars. Frequency comparisons for precipitating convective clouds and non-precipitating high clouds agree much better than non-precipitating low clouds for both scanning radars due to issues in ground clutter. On average, SMART-R underestimates convective and high cloud tops by 0.3 to 1.1 km, while S-Pol underestimates cloud tops by less than 0.4 km for these cloud types. S-Pol shows excellent dynamic range in detecting various types of clouds and therefore its data are well suited for characterizing the evolution of the 3D cloud structures, complementing the profiling KAZR measurements. For detecting non-precipitating low clouds and thin cirrus clouds, KAZR remains the most reliable instrument. However, KAZR is attenuated in heavy precipitation and underestimates cloud top height due to rainfall attenuation 4.3% of the time during DYNAMO/AMIE. An empirical method to correct the KAZR cloud top heights is described, and a merged radar dataset is produced to provide improved cloud boundary estimates, microphysics and radiative heating retrievals.

  10. PROPAGATION OF ALFVN WAVES AT THE PLASMA SHEET BOUNDARY Robert L. Lysak and Yan Song

    E-Print Network [OSTI]

    Lysak, Bob

    PROPAGATION OF ALFVÃ?N WAVES AT THE PLASMA SHEET BOUNDARY LAYER Robert L. Lysak and Yan Song School conversion or by localized plasma flows in the tail. The generation and propagation of these waves is studied nonlinear MHD simulations of wave propagation at the boundary layer. INTRODUCTION Recent observations from

  11. Momentum and heat fluxes in a turbulent air flow over a wet, smooth boundary

    E-Print Network [OSTI]

    Rice, Warren

    1958-01-01T23:59:59.000Z

    Idealized sketch, of boundary layer flow regions................ .............45 Figure 2 Schematic diagram of wind tunnel. . . . 46 Figure 3 Photograph of wind tunnel............ .. 47 Figure 4 Photograph of wind tunnel............ .. 47 Figure 5... mechanism and probe.................. .. 49 Figure 9 Distances of interest in the momentum and thermal boundary layers ............ 50 Figure 10 A typical velocity and temperature profile comparison .................. .. 51 Figure 1 1 Variation...

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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...

  17. A Climatology of Midlatitude Continental Clouds from the ARM SGP Central Facility. Part II: Cloud Fraction and Surface Radiative Forcing

    E-Print Network [OSTI]

    Dong, Xiquan

    at the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility and for single-layered low (0­3 km), middle (3­6 km), and high clouds ( 6 km) using ARM SCF ground-based paired-looking standard precision spectral pyranometers and precision infrared radiometer measurements with uncertainties

  18. Running Boundary Condition

    E-Print Network [OSTI]

    Satoshi Ohya; Makoto Sakamoto; Motoi Tachibana

    2013-01-28T23:59:59.000Z

    In this paper we argue that boundary condition may run with energy scale. As an illustrative example, we consider one-dimensional quantum mechanics for a spinless particle that freely propagates in the bulk yet interacts only at the origin. In this setting we find the renormalization group flow of U(2) family of boundary conditions exactly. We show that the well-known scale-independent subfamily of boundary conditions are realized as fixed points. We also discuss the duality between two distinct boundary conditions from the renormalization group point of view. Generalizations to conformal mechanics and quantum graph are also discussed.

  19. 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...

  20. 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.

  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. 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

  3. 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

  4. 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.

  5. Characterization of melting level clouds over the tropical western pacific warm pool

    SciTech Connect (OSTI)

    Jensen, M.; Johnson, K.; Billings, J.; Troyan, D.; Long, C.; Comstock, J.

    2010-03-15T23:59:59.000Z

    A cursory examination of historical ARSCL data indicates a common cloud feature in the tropics are thin detrainment shelves (Attendant Shelf Clouds, or ASCs) near the melting level (see figure for example). We use the ARSCL product to identify ASCs by defining them as cloud layers with bases above 4 km, a corresponding top below 6 km, and a thickness of less than 1 km. In order to prevent biases in determination of the diurnal cycle of cloud occurrence, we require that both the MMCR and MPL are operating well. In this study we use a total of 55 months of data collected over 14 years of deployments at the Manus, Nauru, and Darwin ARM sites in the Tropical Western Pacific to define the frequency of occurrence (~ 14% of the time) and diurnal cycle of these clouds, along with the atmospheric thermodynamic profile. We further investigate the horizontal extent, cloud radiative forcing, and cloud particle phase through a series of “golden cases” where there is a general absence of additional cloud types in the column and nearby deep convection. These cases indicate that the clouds can cover horizontal areas on the order of a GCM gridbox, have significant (but not always) cloud radiative forcing, and may be composed of liquid or ice water.

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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.

  13. SGP and TWP (Manus) Ice Cloud Vertical Velocities

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

    Kalesse, Heike

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  14. Jupiter's Great Red Spot and zonal winds as a self-consistent, one-layer, quasigeostrophic flow

    E-Print Network [OSTI]

    Marcus, Philip S.

    -value calculations in which the weather layer starts at rest produce oscillatory east-west winds. Like the Jovian stratified with respect to thermal convection. The layer's top boundary is the tropo- pause which acts boundary is the top of an underlying convective zone. Because the layer's stratification (Brunt

  15. GEOPHYSICAL RESEARCH LETTERS, VOL. 28, NO. 13, PAGES 2609-2612, JULY 1, 2001 The death of an altocumulus cloud

    E-Print Network [OSTI]

    relatively few reports of in-situ altocumulus measurements (exceptions in- clude Hobbs and Rangno [1985 of a mid-level cloud that was measured during the Complex Layered Cloud Experiments (CLEX). The budget reasons. First, altocumuli impede pilots' visibility and thereby hamper military operations (Fleishauer et

  16. An Atmospheric Radiation Measurement Value-Added Product to Retrieve Optically Thin Cloud Visible Optical Depth using Micropulse Lidar

    SciTech Connect (OSTI)

    Lo, C; Comstock, JM; Flynn, C

    2006-10-01T23:59:59.000Z

    The purpose of the Micropulse Lidar (MPL) Cloud Optical Depth (MPLCOD) Value-Added Product (VAP) is to retrieve the visible (short-wave) cloud optical depth for optically thin clouds using MPL. The advantage of using the MPL to derive optical depth is that lidar is able to detect optically thin cloud layers that may not be detected by millimeter cloud radar or radiometric techniques. The disadvantage of using lidar to derive optical depth is that the lidar signal becomes attenuation limited when ? approaches 3 (this value can vary depending on instrument specifications). As a result, the lidar will not detect optically thin clouds if an optically thick cloud obstructs the lidar beam.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Boundaries and Topological Algorithms

    E-Print Network [OSTI]

    Fleck, Margaret Morrison

    1988-09-01T23:59:59.000Z

    This thesis develops a model for the topological structure of situations. In this model, the topological structure of space is altered by the presence or absence of boundaries, such as those at the edges of objects. ...

  2. 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...

  3. ARM - Field Campaign - Complex Layered Cloud Experiment (CLEX)

    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)8LigovCampaignsCLEX-5 CampaignSP2 Deployment at StormVEx

  4. Intrusive gravity currents in two-layer

    E-Print Network [OSTI]

    Flynn, Morris R.

    Intrusive gravity currents in two-layer stratified media Morris R. Flynn & Paul F. Linden Dept.avalanche.org/pictures #12;· `Microbursts' pose a non-trivial threat to airplane safety Introduction Impacts on human health;· Whereas gravity currents travel along a solid boundary, intrusive gravity currents or intrusions propagate

  5. 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

  6. 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

  7. 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.

  8. Numerical simulations of the stratified oceanic bottom boundary layer

    E-Print Network [OSTI]

    Taylor, John R.

    2008-01-01T23:59:59.000Z

    approximation that the mean wave energy and the backgroundfound that only 6% of the wave energy was re?ected back fromfound that the internal wave energy spec- trum in the outer

  9. Supersonic turbulent boundary layers with periodic mechanical non-equilibrium 

    E-Print Network [OSTI]

    Ekoto, Isaac Wesley

    2007-04-25T23:59:59.000Z

    questions have been raised. The fundamental questions this dissertation addressed are: (1) What are the effects of wall topology with sharp versus blunt leading edges? and (2) Is it possible that a further reduction of turbulent scales can occur if surface...

  10. EXPERIMENTAL STUDY OF COMBUSTION IN A TURBULENT BOUNDARY LAYER

    E-Print Network [OSTI]

    Cheng, R.K.

    2011-01-01T23:59:59.000Z

    States Section of the Combustion Institute, Stanford, CA,Cheng, R. K. , "Catalyzed Combustion of H2/ Air Mixtures inWorkshop on Catalytic Combustion, Asheville, North Carolina,

  11. A Note on the Intermediate Region in Turbulent Boundary Layers

    E-Print Network [OSTI]

    G. I. Barenblatt; A. J. Chorin; V. M. Prostokishin

    2000-02-16T23:59:59.000Z

    We demonstrate that the processing of the experimental data for the average velocity profiles obtained by J. M. \\"Osterlund (www.mesh.kth.se/$\\sim$jens/zpg/) presented in [1] was incorrect. Properly processed these data lead to the opposite conclusion: they confirm the Reynolds-number-dependent scaling law and disprove the conclusion that the flow in the intermediate (`overlap') region is Reynolds-number-independent.

  12. DIRECT SIMULATION OF SPATIALLY EVOLVING COMPRESSIBLE TURBULENT BOUNDARY LAYERS

    E-Print Network [OSTI]

    Erlebacher, Gordon

    of the cold wall condition used in Ref. 6, and, other differences. The computational method used in this study compressible flows because of the interest in designing high speed vehicles and the associated propulsion on temperature. Under the adiabatic conditions of the experiment, the temperature increases as the wall

  13. Control of the Transitional Boundary Layer Brandt A. Belson

    E-Print Network [OSTI]

    Rowley, Clarence W.

    in the presence of unmodeled disturbances. Next, we focus on a specific type of actuator, the single dielectric barrier discharge (SDBD) plasma actuator. An array of these plasma actuators is oriented to produce stream such that the controllers perform well when applied to the experiment. Lastly, we also simulate the plasma actuators

  14. THERMOPHORESIS OF PARTICLES IN A HEATED BOUNDARY LAYER

    E-Print Network [OSTI]

    Talbot, L.

    2012-01-01T23:59:59.000Z

    I (f) X Fig. 6 Reduced thermophoretic force as a function offrom the plate surface by thermophoretic forces. causing aseveral theories for the thermophoretic force. It was found

  15. absorbing boundary layers: Topics by E-print Network

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

    limits: (a) Pr>1, Pr1 and (b) Pr>>1. These two theoretical predictions are in excellent agreement with the results of our direct numerical simulations for Pr4.38 (water) and...

  16. IMPACT OF BOUNDARY-LAYER CUTTING ON FREE-SURFACE

    E-Print Network [OSTI]

    California at San Diego, University of

    height ~ 1 m · Overall height ~ 5.5 m E Flow conditionerE Flow conditioner F NozzleF Nozzle G Liquid

  17. ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure

    E-Print Network [OSTI]

    McHenry, Matt

    force coefficient for fluid c speed of sound in water C integration constant Em Young's modulus of cupular matrix F stimulus frequency Fb buoyant force Fe elastic force Fm inertial force Fa acceleration

  18. The effect of tangential blowing on boundary-layer profiles

    E-Print Network [OSTI]

    Olson, Milford Eugene

    1967-01-01T23:59:59.000Z

    downstream of the slot. The width of the slot was set at 0. 013, 0. 033, and 0. 0415 inches. The blowing rates were varied to give a jet velocity of approximately 0, 163, 246, and 2 /5 feet per s cond. Results of the data are presented in graphical...; Blowing Rate Symbols B) B2 B 3 Cl C 2 C 3 D V (fps) J 163 246 2 75 163 246 275 163 Bjowing Rale (ft /sec) . 3 0. 0418 0. 0630 0. 0705 0. 1061 0. 1600 0. 1790 0. 1333 D D 3 246 275 0. 2013 0. 2250 A theory which expressed a...

  19. Experimental and theoretical study of turbulent oscillatory boundary layers

    E-Print Network [OSTI]

    Yuan, Jing, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Sediment transport is of crucial importance to engineering projects in coastal regions, so it is of primary interest in coastal engineering. The driving forces for sediment transport are mostly determined by the hydrodynamics ...

  20. Supersonic turbulent boundary layers with periodic mechanical non-equilibrium

    E-Print Network [OSTI]

    Ekoto, Isaac Wesley

    2007-04-25T23:59:59.000Z

    questions have been raised. The fundamental questions this dissertation addressed are: (1) What are the effects of wall topology with sharp versus blunt leading edges? and (2) Is it possible that a further reduction of turbulent scales can occur if surface...

  1. Thermal boundary layer development in dispersed flow film boiling

    E-Print Network [OSTI]

    Hull, Lawrence M.

    1982-01-01T23:59:59.000Z

    Dispersed flow film boiling consists of a dispersion of droplets which are carried over a very hot surface by their vapor. This process occurs in cryogenic equipment and wet steam turbines. It is also of interest in the ...

  2. Linear Stability Analysis of a Boundary Layer with Plasma Actuators

    E-Print Network [OSTI]

    Roy, Subrata

    in the ith direction p Pressure ¯ui Mean flow velocity in the ith direction ¯p Mean pressure ~ui Disturbance flow velocity in the ith direction ~p Disturbance pressure ui Complex 1D disturbance flow velocity Complex spatial frequency in x1 Complex spatial frequency in x3 Complex temporal frequency cp Complex

  3. DIFFUSION OF A CHEMICAL SPECIES THROUGH A VISCOUS BOUNDARY LAYER

    E-Print Network [OSTI]

    Keller, J.

    2011-01-01T23:59:59.000Z

    2.3 Evaluation of a Coal Gasification Atmosphere. . -iv-a highly cor- rosive coal gasification mixture. It is shown2.3 Evaluation of a Coal Gasification Atmosphere The purpose

  4. Boundary layer ingesting inlet design for a silent aircraft

    E-Print Network [OSTI]

    Freuler, Patrick N., 1980-

    2005-01-01T23:59:59.000Z

    (cont.) common nacelle, L/D ratios between 2.5 and 3.0, fan face to throat area ratios above 1.06, and offsets lower than 11%. Curvature ahead of the inlet should be avoided as well as bifurcations inside the duct. Inlet ...

  5. Interaction between surface and atmosphere in a convective boundary layer /

    E-Print Network [OSTI]

    Garai, Anirban

    2013-01-01T23:59:59.000Z

    resulting in constant wind, and potential temperature andatmospheric wind speed, direction and potential temperatureatmospheric profiles (wind speed, potential temperature),

  6. Large-Scale Streamwise Turbulent Structures in Hypersonic Boundary Layers

    E-Print Network [OSTI]

    English, Benjamin L.

    2013-04-22T23:59:59.000Z

    13 Before and after example of pre-processed images........................... 27 14 Average velocity and TKE comparison ............................................ 37 15 Reynolds shear stress comparison... 19 Instantaneous velocity field comparison at ? ..................... 42 20 Instantaneous velocity field comparison at ? ..................... 44 21 Instantaneous velocity field comparison at ? ..................... 45...

  7. OFFSHORE BOUNDARY-LAYER MODELLING H. Bergstrm1

    E-Print Network [OSTI]

    currently be incorporated into a wind farm design tool. The offshore thermal stratification climate is also investigated. 1 INTRODUCTION Mapping the offshore wind climate, it is important to take into account both land contribute to a complex wind field, and affect the wind also at large offshore distances. Spatial variations

  8. ARM - Field Campaign - 2013 Lower Atmospheric Boundary Layer Experiment

    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)8Li (59AJ76)ARM2, 2006 [FacilityMission Under52 NEAQS (New7

  9. ARM - Field Campaign - Lower Atmospheric Boundary Layer Experiment

    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

  10. ARM - PI Product - Planetary Boundary Layer from AERI and MPL

    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 for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDAC

  11. A dual mass flux framework for boundary layer convection

    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,generation high-performanceA dual mass

  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. Spectrum of local boundary operators from boundary form factor bootstrap

    E-Print Network [OSTI]

    M. Szots; G. Takacs

    2007-03-26T23:59:59.000Z

    Using the recently introduced boundary form factor bootstrap equations, we map the complete space of their solutions for the boundary version of the scaling Lee-Yang model and sinh-Gordon theory. We show that the complete space of solutions, graded by the ultraviolet behaviour of the form factors can be brought into correspondence with the spectrum of local boundary operators expected from boundary conformal field theory, which is a major evidence for the correctness of the boundary form factor bootstrap framework.

  14. Transgressing the Boundaries: An Afterword

    E-Print Network [OSTI]

    Sokal, Alan

    the Boundaries: Toward a Transformative Hermeneutics of Quantum Gravity'', which appeared in Social Text #46

  15. Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem

    SciTech Connect (OSTI)

    Dana E. Veron

    2012-04-09T23:59:59.000Z

    This project had two primary goals: (1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and (2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, climatology of cloud properties was developed at the ARM CART sites, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed in the final report.

  16. 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

  17. Discovery of a luminous white dwarf in a young star cluster in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Rebecca A. W. Elson; Steinn Sigurdsson; Jarrod Hurley; Melvyn B. Davies; Gerard F. Gilmore

    1998-03-19T23:59:59.000Z

    We have identified a candidate 1-2 x 10^5 year old luminous white dwarf in NGC 1818, a young star cluster in the Large Magellanic Cloud. This discovery strongly constrains the boundary mass M_c at which stars stop forming neutron stars and start forming white dwarfs, to M_c > 7.6 Msun.

  18. 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

  19. 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 ...

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Wavelet analysis study of microbubble drag reduction in a boundary channel flow 

    E-Print Network [OSTI]

    Zhen, Ling

    2006-04-12T23:59:59.000Z

    Particle Image Velocimetry (PIV) and pressure measurement techniques were performed to investigate the drag reduction due to microbubble injection in the boundary layer of a fully developed turbulent channel flow. ...

  6. Preprint of the paper "A General Formulation based on the Boundary Element Method for the Analysis

    E-Print Network [OSTI]

    Colominas, Ignasi

    cost) to the analysis of large grounding systems in electrical substations. In this paper we present a new Boundary Element formulation for substation grounding systems embedded in layered soils of the substation site. Obviously, from a technical (and

  7. Friction and Diapycnal Mixing at a Slope: Boundary Control of Potential Vorticity

    E-Print Network [OSTI]

    Benthuysen, Jessica

    Although atmospheric forcing by wind stress or buoyancy flux is known to change the ocean’s potential vorticity (PV) at the surface, less is understood about PV modification in the bottom boundary layer. The adjustment of ...

  8. Interface dynamics for layered structures

    E-Print Network [OSTI]

    Takao Ohta; David Jasnow

    1997-07-17T23:59:59.000Z

    We investigate dynamics of large scale and slow deformations of layered structures. Starting from the respective model equations for a non-conserved system, a conserved system and a binary fluid, we derive the interface equations which are a coupled set of equations for deformations of the boundaries of each domain. A further reduction of the degrees of freedom is possible for a non-conserved system such that internal motion of each domain is adiabatically eliminated. The resulting equation of motion contains only the displacement of the center of gravity of domains, which is equivalent to the phase variable of a periodic structure. Thus our formulation automatically includes the phase dynamics of layered structures. In a conserved system and a binary fluid, however, the internal motion of domains turns out to be a slow variable in the long wavelength limit because of concentration conservation. Therefore a reduced description only involving the phase variable is not generally justified.

  9. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15T23:59:59.000Z

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  10. Condition Number Estimates for Combined Potential Boundary Integral

    E-Print Network [OSTI]

    Langdon, Stephen

    Condition Number Estimates for Combined Potential Boundary Integral Operators in Acoustic parameter. Of independent interest we also obtain upper and lower bounds on the norms of two oscillatory integral operators, namely the classical acoustic single- and double-layer potential operators. 1

  11. Condition Number Estimates for Combined Potential Boundary Integral

    E-Print Network [OSTI]

    Langdon, Stephen

    Condition Number Estimates for Combined Potential Boundary Integral Operators in Acoustic parameter. Of independent interest we first obtain upper and lower bounds on the norms of two oscillatory integral operators, namely the classical acoustic single- and double-layer potential operators. 1

  12. 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...

  13. 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

  14. Gas-surface interaction and boundary conditions for the Boltzmann equation

    E-Print Network [OSTI]

    Mieussens, Luc

    Gas-surface interaction and boundary conditions for the Boltzmann equation St´ephane Brull, Pierre Equation. The interaction between the wall atoms and the gas molecules within a thin surface layer of the gas in the bulk flow. Boundary conditions are formally derived from this model by using classical

  15. Boundary transfer matrices and boundary quantum KZ equations

    E-Print Network [OSTI]

    Bart Vlaar

    2014-10-31T23:59:59.000Z

    A simple relation between inhomogeneous transfer matrices and boundary quantum KZ equations is exhibited for quantum integrable systems with reflecting boundary conditions, analogous to an observation by Gaudin for periodic systems. Thus the boundary quantum KZ equations receive a new motivation. We also derive the commutativity of Sklyanin's boundary transfer matrices by merely imposing appropriate reflection equations, i.e. without using the conditions of crossing symmetry and unitarity of the R-matrix.

  16. A new twist on Stokes' second problem: Partial penetration of nonlinearity in sheared viscoelastic layers

    E-Print Network [OSTI]

    Forest, M. Gregory

    viscoelastic layer to an oscillating boundary, greater than the gap-loading limit of typical shear rheometers oscillatory shear driving con- ditions on the mucus layer. Very little evidence is available on the details extend our previous studies [3­5] of viscoelas- tic layers under oscillatory driving conditions

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Cold Water Vapor in the Barnard 5 Molecular Cloud

    E-Print Network [OSTI]

    Wirström, E S; Persson, C M; Buckle, J V; Cordiner, M A; Takakuwa, S

    2014-01-01T23:59:59.000Z

    After more than 30 years of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds, however, there is only one region where cold (~10 K) water vapor has been detected - L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work -- likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 1_10 - 1_01) at 556.9360 GHz toward two positions in the cold molecular cloud Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  13. 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.

  14. 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.

  15. Application of Stochastic Radiative Transfer Theory to the ARM Cloud-Radiative Parameterization Problem

    SciTech Connect (OSTI)

    Veron, Dana E

    2009-03-12T23:59:59.000Z

    This project had two primary goals: 1) development of stochastic radiative transfer as a parameterization that could be employed in an AGCM environment, and 2) exploration of the stochastic approach as a means for representing shortwave radiative transfer through mixed-phase layer clouds. To achieve these goals, an analysis of the performance of the stochastic approach was performed, a simple stochastic cloud-radiation parameterization for an AGCM was developed and tested, a statistical description of Arctic mixed phase clouds was developed and the appropriateness of stochastic approach for representing radiative transfer through mixed-phase clouds was assessed. Significant progress has been made in all of these areas and is detailed below.

  16. 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

  17. A fast multipole boundary element method for 3D multi-domain acoustic scattering problems based on the BurtonMiller formulation

    E-Print Network [OSTI]

    Liu, Yijun

    A fast multipole boundary element method for 3D multi-domain acoustic scattering problems based: Received 9 August 2011 Accepted 30 November 2011 Keywords: Boundary element method Fast multipole method Acoustics Multi-domain Multi-layered Effective moment computations a b s t r a c t A fast multipole boundary

  18. Retrieval of optical and microphysical properties of ice clouds using Atmospheric Radiation Measurement (ARM) data

    E-Print Network [OSTI]

    Kinney, Jacqueline Anne

    2005-11-01T23:59:59.000Z

    is based on a method proposed by Yang et al. (2005). The research examines single-layer ice clouds in the midlatitude and polar regions. The retrieved information in the midlatitudes is then verified using retrievals from the Moderate-resolution Imaging...

  19. 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

  20. 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

  1. 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, ...

  2. Photovoltaic devices comprising zinc stannate buffer layer and method for making

    DOE Patents [OSTI]

    Wu, Xuanzhi (Golden, CO); Sheldon, Peter (Lakewood, CO); Coutts, Timothy J. (Lakewood, CO)

    2001-01-01T23:59:59.000Z

    A photovoltaic device has a buffer layer zinc stannate Zn.sub.2 SnO.sub.4 disposed between the semiconductor junction structure and the transparent conducting oxide (TCO) layer to prevent formation of localized junctions with the TCO through a thin window semiconductor layer, to prevent shunting through etched grain boundaries of semiconductors, and to relieve stresses and improve adhesion between these layers.

  3. Dynamical evolution of supernova remnants breaking through molecular clouds

    E-Print Network [OSTI]

    Cho, Wankee; Koo, Bon-Chul

    2015-01-01T23:59:59.000Z

    We carry out three-dimensional hydrodynamic simulations of the supernova remnants (SNRs) produced inside molecular clouds (MCs) near their surface using the HLL code (Harten et al. 1983). We explore the dynamical evolution and the X-ray morphology of SNRs after breaking through the MC surface for ranges of the explosion depths below the surface and the density ratios of the clouds to the intercloud media (ICM). We find that if an SNR breaks out through an MC surface in its Sedov stage, the outermost dense shell of the remnant is divided into several layers. The divided layers are subject to the Rayleigh-Taylor instability and fragmented. On the other hand, if an SNR breaks through an MC after the remnant enters the snowplow phase, the radiative shell is not divided to layers. We also compare the predictions of previous analytic solutions for the expansion of SNRs in stratified media with our onedimensional simulations. Moreover, we produce synthetic X-ray surface brightness in order to research the center-bri...

  4. Geometry of Weak Stability Boundaries

    E-Print Network [OSTI]

    Edward Belbruno; Marian Gidea; Francesco Topputo

    2012-04-06T23:59:59.000Z

    The notion of a weak stability boundary has been successfully used to design low energy trajectories from the Earth to the Moon. The structure of this boundary has been investigated in a number of studies, where partial results have been obtained. We propose a generalization of the weak stability boundary. We prove analytically that, in the context of the planar circular restricted three-body problem, under certain conditions on the mass ratio of the primaries and on the energy, the weak stability boundary about the heavier primary coincides with a branch of the global stable manifold of the Lyapunov orbit about one of the Lagrange points.

  5. 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.

  6. A simplex model for layered niche networks

    E-Print Network [OSTI]

    P. Fraundorf

    2007-03-06T23:59:59.000Z

    The standing crop of correlations in metazoan communities may be assessed by an inventory of niche structures focused inward and outward from the physical boundaries of skin (self), gene-pool (family), and meme-pool (culture). We consider tracking the progression from three and four correlation layers in many animal communities, to five of six layers for the shared adaptation of most humans, with an attention-slice model that maps the niche-layer focus of individuals onto the 6-variable space of a 5-simplex. The measure puts questions about the effect, on culture and species, of policy and natural events into a common context, and may help explore the impact of electronically-mediated codes on community health.

  7. 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...

  8. Prospects for Simulating Macromolecular Surfactant Chemistry at the Ocean-Atmosphere Boundary

    SciTech Connect (OSTI)

    Elliott, S.; Burrows, Susannah M.; Deal, C.; Liu, Xiaohong; Long, M.; Ogunro, O.; Russell, Lynn M.; Wingenter, O.

    2014-05-01T23:59:59.000Z

    Biogenic lipids and polymers are surveyed for their ability to adsorb at the water-air interfaces associated with bubbles, marine microlayers and particles in the overlying boundary layer. Representative ocean biogeochemical regimes are defined in order to estimate local concentrations for the major macromolecular classes. Surfactant equilibria and maximum excess are then derived based on a network of model compounds. Relative local coverage and upward mass transport follow directly, and specific chemical structures can be placed into regional rank order. Lipids and denatured protein-like polymers dominate at the selected locations. The assigned monolayer phase states are variable, whether assessed along bubbles or at the atmospheric spray droplet perimeter. Since oceanic film compositions prove to be irregular, effects on gas and organic transfer are expected to exhibit geographic dependence as well. Moreover, the core arguments extend across the sea-air interface into aerosol-cloud systems. Fundamental nascent chemical properties including mass to carbon ratio and density depend strongly on the geochemical state of source waters. High surface pressures may suppress the Kelvin effect, and marine organic hygroscopicities are almost entirely unconstrained. While bubble adsorption provides a well-known means for transporting lipidic or proteinaceous material into sea spray, the same cannot be said of polysaccharides. Carbohydrates tend to be strongly hydrophilic so that their excess carbon mass is low despite stacked polymeric geometries. Since sugars are abundant in the marine aerosol, gel-based mechanisms may be required to achieve uplift. Uncertainties in the surfactant logic distill to a global scale dearth of information regarding two dimensional kinetics and equilibria. Nonetheless simulations are recommended, to initiate the process of systems level quantification.

  9. 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 ...

  10. 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...

  11. 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 ...

  12. Evidence for Cloud Disruption in the L/T Dwarf Transition

    E-Print Network [OSTI]

    Adam J. Burgasser; Mark S. Marley; Andrew S. Ackerman; Didier Saumon; Katharina Lodders; Conard C. Dahn; Hugh C. Harris; J. Davy Kirkpatrick

    2002-05-03T23:59:59.000Z

    Clouds of metal-bearing condensates play a critical role in shaping the emergent spectral energy distributions of the coolest classes of low-mass stars and brown dwarfs, L and T dwarfs. Because condensate clouds in planetary atmospheres show distinct horizontal structure, we have explored a model for partly cloudy atmospheres in brown dwarfs. Our model successfully reproduces the colors and magnitudes of both L and T dwarfs for the first time, including the unexpected brightning of the early- and mid-type T dwarfs at J-band, provided that clouds are rapidly removed from the photosphere at T_eff ~ 1200 K. The clearing of cloud layers also explains the surprising persistence and strengthening of gaseous FeH bands in early- and mid-type T dwarfs. The breakup of cloud layers is likely driven by convection in the troposphere, analogous to phenomena observed on Jupiter. Our results demonstrate that planetary-like atmospheric dynamics must be considered when examining the evolution of free-floating brown dwarfs.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  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. Cell boundary fault detection system

    DOE Patents [OSTI]

    Archer, Charles Jens (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian Edward (Rochester, MN)

    2011-04-19T23:59:59.000Z

    An apparatus and program product determine a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  7. Recursion Relation for Boundary Contribution

    E-Print Network [OSTI]

    Qingjun Jin; Bo Feng

    2015-05-01T23:59:59.000Z

    It is well known that under a BCFW-deformation, there is a boundary contribution when the amplitude scales as O(1) or worse. We show that boundary contributions have a similar recursion relation as scattering amplitude. Just like the BCFW recursion relation, where scattering amplitudes are expressed as the products of two on-shell sub-amplitudes (plus possible boundary contributions), our new recursion relation expresses boundary contributions as products of sub-amplitudes and boundary contributions with less legs, plus yet another possible boundary contribution. In other words, the complete scattering amplitude, including boundary contributions, can be obtained by multiple steps of recursions, unless the boundary contributions are still non-zero when all possible deformations are exploited. We demonstrate this algorithm by several examples. Especially, we show that for standard model like renormalizable theory in 4D, i.e., the theory including only gauge boson, fermions and scalars, the complete amplitude can always be computed by at most four recursive steps using our algorithm.

  8. Photonic layered media

    DOE Patents [OSTI]

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

  9. 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.

  10. 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...

  11. Turbulence structure of the surface layer Boun 2247-03D TURBULENCE STRUCTURE OF THE UNSTABLE ATMOSPHERIC

    E-Print Network [OSTI]

    Moncrieff, John B.

    to the creation of emerging TEAL structures to the power passing down the Richardson cascade in the outer layer-Obukhov similarity, self-organizing systems 1. Introduction In convective boundary layers the structureTurbulence structure of the surface layer Boun 2247-03D TURBULENCE STRUCTURE OF THE UNSTABLE

  12. Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow

    E-Print Network [OSTI]

    Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow to be an important effect for the formation of ripples and the dynamics of the boundary layer above a predominantly), Formation of a sandy near-bed transport layer from a fine-grained bed under oscillatory flow, J. Geophys

  13. 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...

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. Cloud Security: Issues and Concerns Pierangela Samarati*

    E-Print Network [OSTI]

    Samarati, Pierangela

    1 Cloud Security: Issues and Concerns Authors Pierangela Samarati* Università 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Vacuum Structure and Boundary Renormalization Group

    E-Print Network [OSTI]

    M. Asorey; J. M. Munoz-Castaneda

    2007-12-28T23:59:59.000Z

    The vacuum structure is probed by boundary conditions. The behaviour of thermodynamical quantities like free energy, boundary entropy and entanglement entropy under the boundary renormalization group flow are analysed in 2D conformal field theories. The results show that whereas vacuum energy and boundary entropy turn out to be very sensitive to boundary conditions, the vacuum entanglement entropy is independent of boundary properties when the boundary of the entanglement domain does not overlap the boundary of the physical space. In all cases the second law of thermodynamics holds along the boundary renormalization group flow.

  6. Fine-scale Horizontal Structure of Arctic Mixed-Phase Clouds.

    SciTech Connect (OSTI)

    Rambukkange,M.; Verlinde, J.; Elorante, E.; Luke, E.; Kollias, P.; Shupe, M.

    2006-07-10T23:59:59.000Z

    Recent in situ observations in stratiform clouds suggest that mixed phase regimes, here defined as limited cloud volumes containing both liquid and solid water, are constrained to narrow layers (order 100 m) separating all-liquid and fully glaciated volumes (Hallett and Viddaurre, 2005). The Department of Energy Atmospheric Radiation Measurement Program's (DOE-ARM, Ackerman and Stokes, 2003) North Slope of Alaska (NSA) ARM Climate Research Facility (ACRF) recently started collecting routine measurement of radar Doppler velocity power spectra from the Millimeter Cloud Radar (MMCR). Shupe et al. (2004) showed that Doppler spectra has potential to separate the contributions to the total reflectivity of the liquid and solid water in the radar volume, and thus to investigate further Hallett and Viddaurre's findings. The Mixed-Phase Arctic Cloud Experiment (MPACE) was conducted along the NSA to investigate the properties of Arctic mixed phase clouds (Verlinde et al., 2006). We present surface based remote sensing data from MPACE to discuss the fine-scale structure of the mixed-phase clouds observed during this experiment.

  7. ON THE ACOUSTIC SINGLE LAYER POTENTIAL: STABILIZATION AND FOURIER ANALYSIS

    E-Print Network [OSTI]

    Buffa, Annalisa

    ON THE ACOUSTIC SINGLE LAYER POTENTIAL: STABILIZATION AND FOURIER ANALYSIS A. BUFFA AND S. SAUTER in the stability and convergence estimates attains its minumum. Key words. Acoustic scattering, Galerkin boundary discretizations for the Helmholtz problem suffer from the pollution effect, i.e., the constants in the Galerkin

  8. Electric Field in a Double Layer and the Imparted Momentum

    SciTech Connect (OSTI)

    Fruchtman, A. [Holon Academic Institute of Technology, 52 Golomb Street, Holon 58102 (Israel)

    2006-02-17T23:59:59.000Z

    It is shown that the net momentum delivered by the large electric field inside a one-dimensional double layer is zero. This is demonstrated through an analysis of the momentum balance in the double layer at the boundary between the ionosphere and the aurora cavity. For the recently observed double layer in a current-free plasma expanding along a divergent magnetic field, an analysis of the evolution of the radially averaged variables shows that the increase of plasma thrust results from the magnetic-field pressure balancing the plasma pressure in the direction of acceleration, rather than from electrostatic pressure.

  9. 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

  10. 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.

  11. Layered plasma polymer composite membranes

    DOE Patents [OSTI]

    Babcock, W.C.

    1994-10-11T23:59:59.000Z

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  12. Boundary Waters Canoe Area (Minnesota)

    Broader source: Energy.gov [DOE]

    The Boundary Waters Canoe Area occupies a large section of northern Minnesota, and is preserved as a primitive wilderness area. Construction and new development is prohibited. A map of the...

  13. Cross-Layer Attack and Defense in Cognitive Radio Networks Wenkai Wang and Yan (Lindsay) Sun

    E-Print Network [OSTI]

    Sun, Yan Lindsay

    Cross-Layer Attack and Defense in Cognitive Radio Networks Wenkai Wang and Yan (Lindsay) Sun ECE research on security issues in cognitive radio networks mainly focuses on attack and defense in individual network layers. However, the attackers do not necessarily restrict themselves within the boundaries

  14. The viscosity structure of the D00 layer of the Earth's mantle inferred

    E-Print Network [OSTI]

    The viscosity structure of the D00 layer of the Earth's mantle inferred from the analysis layer Core­mantle boundary Viscosity Maxwell body a b s t r a c t The viscosity structure of the D00-diurnal to 18.6 years tidal deformations combined with model viscosity­depth profiles corresponding to a range

  15. Changing the Structure Boundary Geometry

    SciTech Connect (OSTI)

    Karasev, Viktor; Dzlieva, Elena; Ivanov, Artyom [St.-Petersburg State University, Physics Faculty, Ulianovskaya 1, Peterhof, St. Petersburg, 198504 (Russian Federation)

    2008-09-07T23:59:59.000Z

    Analysis of previously obtained results shows that hexagonal crystal lattice is the dominant type of ordering, in particular, in striated glow discharges. We explore the possibility for changing the dust distribution in horizontal cross sections of relatively highly ordered structures in a glow-discharge. Presuming that boundary geometry can affect dust distribution, we used cylindrical coolers held at 0 deg. C and placed against a striation containing a structure, to change the geometry of its outer boundary. By varying the number of coolers, their positions, and their separations from the tube wall, azimuthally asymmetric thermophoretic forces can be used to form polygonal boundaries and vary the angles between their segments (in a horizontal cross section). The corner in the structure's boundary of 60 deg. stimulates formation of hexagonal cells. The structure between the supported parallel boundaries is also characterized by stable hexagonal ordering. We found that a single linear boundary segment does not give rise to any sizable domain, but generates a lattice extending from the boundary (without edge defects). A square lattice can be formed by setting the angle equal to 90 deg. . However, angles of 45 deg. and 135 deg. turned out easier to form. Square lattice was created by forming a near-135 deg. corner with four coolers. It was noted that no grain ordering is observed in the region adjacent to corners of angles smaller than 30 deg. , which do not promote ordering into cells of any shape. Thus, manipulation of a structure boundary can be used to change dust distribution, create structures free of the ubiquitous edge defects that destroy orientation order, and probably change the crystal lattice type.

  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. Strain tensors in layer systems by precision ion channeling measurements

    SciTech Connect (OSTI)

    Trinkaus, H.; Buca, D.; Hollaender, B.; Minamisawa, R. A.; Mantl, S. [Institute of Bio- and Nanosystems (IBN 1) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hartmann, J. M. [CEA-LETI, MINATEC, 17 Rue des Martyrs, F-38054 Grenoble, Cedex 9 (France)

    2010-06-15T23:59:59.000Z

    A powerful method for analyzing general strain states in layer systems is the measurement of changes in the ion channeling directions. We present a systematic derivation and compilation of the required relations between the strain induced angle changes and the components of the strain tensor for general crystalline layer systems of reduced symmetry compared to the basic (cubic) crystal. It is shown that, for the evaluation of channeling measurements, virtually all layers of interest may be described as being 'pseudo-orthorhombic'. The commonly assumed boundary conditions and the effects of surface misorientations on them are discussed. Asymmetric strain relaxation in layers of reduced symmetry is attributed to a restriction in the slip system of the dislocations inducing it. The results are applied to {l_brace}110{r_brace}SiGe/Si layer systems.

  18. Layered Cathode Materials

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

    Layered Cathode Materials presented by Michael Thackeray Chemical Sciences and Engineering Division, Argonne Annual Merit Review DOE Vehicle Technologies Program Washington, D.C....

  19. A bridging technique to analyze the influence of boundary conditions on instability patterns

    SciTech Connect (OSTI)

    Hu Heng, E-mail: huheng@whu.edu.c [School of Civil Engineering, Wuhan University, 8 South Road of East Lake, 430072 Wuhan (China); Damil, Noureddine, E-mail: noureddine.damil@gmail.co [Laboratoire de Calcul Scientifique en Mecanique, Faculte des Sciences Ben M'Sik, Universite Hassan II Mohammedia-Casablanca, Sidi Othman, Casablanca (Morocco); Potier-Ferry, Michel, E-mail: michel.potierferry@univ-metz.f [Laboratoire d'Etude des Microstructures et de Mecanique des Materiaux, LEM3, UMR CNRS 7239, Universite Paul Verlaine-Metz, Ile du Saulcy, 57045 Metz Cedex 01 (France)

    2011-05-10T23:59:59.000Z

    In this paper, we present a new numerical technique that permits to analyse the effect of boundary conditions on the appearance of instability patterns. Envelope equations of Landau-Ginzburg type are classically used to predict pattern formation, but it is not easy to associate boundary conditions for these macroscopic models. Indeed, envelope equations ignore boundary layers that can be important, for instance in cases where the instability starts first near the boundary. In this work, the full model is considered close to the boundary, an envelope equation in the core and they are bridged by the Arlequin method . Simulation results are presented for the problem of buckling of long beams lying on a non-linear elastic foundation.

  20. Layering as Optimization Decomposition 3-1 Layering as OptimizationLayering as Optimization

    E-Print Network [OSTI]

    Fan, Xingzhe

    1 Layering as Optimization Decomposition 3-1 Layering as OptimizationLayering as Optimization DecompositionDecomposition Layering as Optimization Decomposition 3-2 CONTENTSCONTENTS Introduction (Marta;2 Layering as Optimization Decomposition 3-3 Layering as Optimization Decomposition Introduction By Marta

  1. Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging LIDAR.

    SciTech Connect (OSTI)

    Love, Steven P.; Davis, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Tellier, L. L. (Larry L.); Ho, Cheng,

    2002-01-01T23:59:59.000Z

    At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data oti various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

  2. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA)

    1994-01-01T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  3. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06T23:59:59.000Z

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  4. Radiative Energy Balance in the Tropical Tropopause Layer: An Investigation with ARM Data

    SciTech Connect (OSTI)

    Fu, Qiang

    2013-10-22T23:59:59.000Z

    The overall objective of this project is to use the ARM observational data to improve our understanding of cloud-radiation effects in the tropical tropopause layer (TTL), which is crucial for improving the simulation and prediction of climate and climate change. In last four and half years, we have been concentrating on (i) performing the comparison of the ice cloud properties from the ground-based lidar observations with those from the satellite CALIPSO lidar observations at the ARM TWP sites; (ii) analyzing TTL cirrus and its relation to the tropical planetary waves; (iii) calculating the radiative heating rates using retrieved cloud microphysical properties by combining the ground-based lidar and radar observations at the ARM TWP sites and comparing the results with those using cloud properties retrieved from CloudSat and CALIPSO observations; (iv) comparing macrophysical properties of tropical cirrus clouds from the CALIPSO satellite and from ground-based micropulse and Raman lidar observations; (v) improving the parameterization of optical properties of cirrus clouds with small effective ice particle sizes; and (vi) evaluating the enhanced maximum warming in the tropical upper troposphere simulated by the GCMs. The main results of our research efforts are reported in the 12 referred journal publications that acknowledge the DOE Grant No. DE-FG02-09ER64769.

  5. Multiple layer insulation cover

    DOE Patents [OSTI]

    Farrell, James J. (Livingston Manor, NY); Donohoe, Anthony J. (Ovid, NY)

    1981-11-03T23:59:59.000Z

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  6. Ozone Depletion: Part 2 Antarctic Ozone Hole: Each spring, the ozone layer thins over the poles.

    E-Print Network [OSTI]

    Schofield, Jeremy

    Ozone Depletion: Part 2 Antarctic Ozone Hole: Each spring, the ozone layer thins over the poles breaks down before sunlight returns: smaller ozone hole { Formation of polar stratospheric clouds (PSC #3; Photo-initiation reactions: Cl 2 h#23; ! 2Cl HOCl h#23; ! OH + Cl #3; Rapid destruction of ozone

  7. Title: Ontario Greenbelt Boundary File Data Creator /

    E-Print Network [OSTI]

    Greenbelt Act 2005. Data contains three shapefiles: Greenbelt Designated Areas, Outer Boundary and River

  8. Computer Modeling of Transport of Oxidizing Species in Grain Boundaries during Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2014-06-01T23:59:59.000Z

    Zirconium (Zr) based alloys are widely used as the cladding materials in light-water reactors. The water-side corrosion of these alloys degrades their structural integrity and poses serious safety concerns. During the Zr corrosion process, a thin Zr oxide (ZrO2) layer forms on the alloy surface and serves as a barrier layer for further corrosion. The majority of the oxide has the monoclinic phase. At the transition region between the oxide and the metal, the oxide contains a thin layer of stabilized tetragonal phase. It is found that the texture of the tetragonal layer determines the protectiveness of the oxide for corrosion. The transport of oxidizing species, such as anion defects, cation defects, and electron through the tetragonal oxide layer could be the rate limiting step of the corrosion. The defect diffusion can be affected by the growing stresses and microstructures such as grain boundaries and dislocations. In this work molecular dynamics simulations are used to investigate the anion and cation diffusion in bulk and at grain boundaries in tetragonal ZrO2. The results show that defect diffusion at grain boundaries is complex and the behavior strongly depends on the grain boundary type. For most of the grain boundaries studied the defect diffusion are much slower than in the bulk, implying that grain boundaries may not be fast defect transport paths during corrosion. The connection between the modeling results and published experimental work will also be discussed. This work is funded by the Laboratory Directed Research and Development (LDRD) program at Idaho National Laboratory.

  9. 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...

  10. Energy and water vapor transport across a simplified cloud-clear air interface

    E-Print Network [OSTI]

    Gallana, Luca; De Santi, Francesca; Iovieno, Michele; Tordella, Daniela

    2015-01-01T23:59:59.000Z

    We consider a simplified physics of the could interface where condensation, evaporation and radiation are neglected and momentum, thermal energy and water vapor transport is represented in terms of the Boussinesq model coupled to a passive scalar transport equation for the vapor. The interface is modeled as a layer separating two isotropic turbulent regions with different kinetic energy and vapor concentration. In particular, we focus on the small scale part of the inertial range as well as on the dissipative range of scales which are important to the micro-physics of warm clouds. We have numerically investigated stably stratified interfaces by locally perturbing at an initial instant the standard temperature lapse rate at the cloud interface and then observing the temporal evolution of the system. When the buoyancy term becomes of the same order of the inertial one, we observe a spatial redistribution of the kinetic energy which produce a concomitant pit of kinetic energy within the mixing layer. In this sit...

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. ICE AND DUST IN THE PRESTELLAR DARK CLOUD LYNDS 183: PREPLANETARY MATTER AT THE LOWEST TEMPERATURES

    SciTech Connect (OSTI)

    Whittet, D. C. B.; Poteet, C. A.; Bajaj, V. M.; Horne, D. [Department of Physics, Applied Physics and Astronomy and New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Chiar, J. E. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Pagani, L. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, 61 Av. de l'Observatoire, F-75014 Paris (France); Shenoy, S. S. [SOFIA Science Center, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (United States); Adamson, A. J. [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile)

    2013-09-10T23:59:59.000Z

    Dust grains are nucleation centers and catalysts for the growth of icy mantles in quiescent interstellar clouds, the products of which may accumulate into preplanetary matter when new stars and solar systems form within the clouds. In this paper, we present the first spectroscopic detections of silicate dust and the molecular ices H{sub 2}O, CO, and CO{sub 2} in the vicinity of the prestellar core L183 (L134N). An infrared photometric survey of the cloud was used to identify reddened background stars, and we present spectra covering solid-state absorption features in the wavelength range 2-20 {mu}m for nine of them. The mean composition of the ices in the best-studied line of sight (toward J15542044-0254073) is H{sub 2}O:CO:CO{sub 2} Almost-Equal-To 100:40:24. The ices are amorphous in structure, indicating that they have been maintained at low temperature ({approx}< 15 K) since formation. The ice column density N(H{sub 2}O) correlates with reddening by dust, exhibiting a threshold effect that corresponds to the transition from unmantled grains in the outer layers of the cloud to ice-mantled grains within, analogous to that observed in other dark clouds. A comparison of results for L183 and the Taurus and IC 5146 dark clouds suggests common behavior, with mantles first appearing in each case at a dust column corresponding to a peak optical depth {tau}{sub 9.7} = 0.15 {+-} 0.03 in the silicate feature. Our results support a previous conclusion that the color excess E{sub J-K} does not obey a simple linear correlation with the total dust column in lines of sight that intercept dense clouds. The most likely explanation is a systematic change in the optical properties of the dust as the density increases.

  19. 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

  20. 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

  1. 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

  2. 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

  3. The Design of a Community Science Cloud: The Open Science Data Cloud Perspective

    E-Print Network [OSTI]

    Grossman, Robert

    The Design of a Community Science Cloud: The Open Science Data Cloud Perspective Robert L. Grossman, Matthew Greenway, Allison P. Heath, Ray Powell, Rafael D. Suarez, Walt Wells, and Kevin White University Abstract--In this paper we describe the design, and implemen- tation of the Open Science Data Cloud

  4. From Grid to private Clouds, to interClouds. Project Team

    E-Print Network [OSTI]

    Vialle, Stéphane

    24/10/2011 1 From Grid to private Clouds, to interClouds. AlGorille Project Team An overviewGorille INRIA Project Team October 21, 2011 I Premise of Grid ComputingI Premise of Grid Computing... From Grid to private Clouds, to inter

  5. LETTER The incidence and implications of clouds for cloud forest plant water relations

    E-Print Network [OSTI]

    Goldsmith, Greg

    , the montane forest experienced higher precipi- tation, cloud cover and leaf wetting events of longer duration for an improved understanding of clouds and their effects on cloud forest plant functioning. As summarised below (VPD) and photosynthetically active radiation. In turn, this decreases plant water demand. The suppres

  6. Variations in Cloud Cover and Cloud Types over the Ocean from Surface Observations, 19542008

    E-Print Network [OSTI]

    Hochberg, Michael

    ). MSC therefore have a cooling ef- fect on climate [negative cloud radiative effect (CRE)]. Randall et in climate, affecting both radiation fluxes and latent heat fluxes, but the various cloud types affect marine. By contrast, high (cirriform) clouds are thinner and colder, so their longwave effect dominates, giving them

  7. Measurements of grain boundary properties in nanocrystalline ceramics

    SciTech Connect (OSTI)

    Chiang, Y.M.; Smyth, I.P.; Terwilliger, C.D. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering); Petuskey, W.T. (Arizona State Univ., Tempe, AZ (USA). Dept. of Chemistry); Eastman, J.A. (Argonne National Lab., IL (USA))

    1990-11-01T23:59:59.000Z

    The advent of nanocrystalline ceramics prepared by a variety of solution-chemical and vapor deposition methods offers a unique opportunity for the determination grain boundary properties by bulk'' thermodynamic methods. In this paper we discuss results from two types of measurements on model nanocrystalline ceramics. The first is a solution thermodynamic measurement of the activity of nanocrystalline SiC in polycarbosilane-derived silicon carbide fibers (Nicalon). Structural studies have shown that Nicalon consists of well-ordered cubic ({beta} or 3C polytype) SiC grains separated by a very thin grain boundary layer (<1 nm thick) containing the oxygen. The physical properties and chemical reactivity of these fibers are distinctly different from that of bulk silicon carbide. Direct measurement of the alloy composition and analysis of the microstructure has allowed the dissolution reaction to be identified and a lower limit for the SiC activity in the nanocrystalline form to be determined. A second method of measuring grain boundary properties we have investigated for nanocrystalline Si and TiO{sub 2} is high temperature calorimetry. In appropriate samples the grain boundary enthalpy can be measured through the heat evolved during grain growth. Preliminary results on nanocrystalline Si prepared by the recrystallization of amorphous evaporated films and on TiO{sub 2} condensed from the vapor phase are discussed. 29 refs., 3 figs., 1 tab.

  8. Assessing Cloud Spatial and Vertical Distribution with Infrared Cloud Analyzer

    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 DocumentationProductsAlternativeOperational Management »EnergyHubs | DepartmentCloud Spatial

  9. Are nanophase grain boundaries anomalous?

    SciTech Connect (OSTI)

    Stern, E.A.; Siegel, R.W.; Newville, M.; Sanders, P.G.; Haskel, D. [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States)] [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States); [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); [Materials Science and Engineering Department, Northwestern University, Evanston, Illinois 60208 (United States)

    1995-11-20T23:59:59.000Z

    The grain boundary regions of nanophase Cu metal are investigated using the x-ray absorption fine structure (XAFS) technique. Typical samples made by standard techniques need to be greatly thinned if measured in transmission in order to eliminate experimental artifacts which erroneously lower the apparent coordination number. To avoid this problem the samples were measured by the total electron yield technique. The results indicate a grain boundary structure which, on the average, is similar to that in conventional polycrystalline Cu, contrary to previous XAFS measurements made in transmission which indicated a lower coordination number. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

  10. Compliant layer chucking surface

    DOE Patents [OSTI]

    Blaedel, Kenneth L. (Dublin, CA); Spence, Paul A. (Pleasanton, CA); Thompson, Samuel L. (Pleasanton, CA)

    2004-12-28T23:59:59.000Z

    A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

  11. Shoring up Infrastructure Weaknesses with Hybrid Cloud Storage

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Shoring up Infrastructure Weaknesses with Hybrid Cloud Storage #12;2StorSimple White Pages: Shoring Up Infrastructure Weaknesses with Hybrid Cloud Storage Table of Contents The Hybrid Cloud Context for IT Managers ............................................................. 3 The Bottleneck of Managing Storage

  12. A cloud-assisted design for autonomous driving

    E-Print Network [OSTI]

    Suresh Kumar, Swarun

    This paper presents Carcel, a cloud-assisted system for autonomous driving. Carcel enables the cloud to have access to sensor data from autonomous vehicles as well as the roadside infrastructure. The cloud assists autonomous ...

  13. Aneka Cloud Application Platform and Its Integration with Windows Azure

    E-Print Network [OSTI]

    Melbourne, University of

    scheduling, and energy efficient resource utilization. The Aneka Cloud Application platform, together. Ltd., Melbourne, Victoria, Australia 2 Cloud Computing and Distributed Systems (CLOUDS) Laboratory, Department of Computer Science and Software Engineering, The University of Melbourne, Australia Abstract

  14. Fair-weather clouds hold dirty secret | EMSL

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

    Fair-weather clouds hold dirty secret Fair-weather clouds hold dirty secret Released: May 05, 2013 New study reveals particles that seed small-scale clouds over Oklahoma Air...

  15. E-Cloud Build-up in Grooved Chambers

    E-Print Network [OSTI]

    Venturini, Marco

    2007-01-01T23:59:59.000Z

    and F. Zimmermann, ”LC e-Cloud Activities at CERN”, talkal. , Simulations of the Electron Cloud for Vari- ous Con?E-CLOUD BUILD-UP IN GROOVED CHAMBERS ? M. Venturini † LBNL,

  16. Building Dynamic Computing Infrastructures over Distributed Clouds Pierre Riteau

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Building Dynamic Computing Infrastructures over Distributed Clouds Pierre Riteau University--The emergence of cloud computing infrastructures brings new ways to build and manage computing systems objectives. First, leveraging virtualization and cloud computing infrastruc- tures to build distributed large

  17. 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

  18. Consistent cloud computing storage as the basis for distributed applications

    E-Print Network [OSTI]

    Anderson, James William

    2011-01-01T23:59:59.000Z

    Messaging in Cloud Computing . . . . . . . . . .7 1.4Eucalyptus Open—Source Cloud—Computing System. In C'C&#http://www.eweek.com/c/a/Cloud-Computing/Amazons—Head—Start—

  19. 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.

  20. Thermal convection in a spherical shell with melting/freezing at either or both of its boundaries

    E-Print Network [OSTI]

    Deguen, Renaud

    2013-01-01T23:59:59.000Z

    In a number of geophysical or planetological settings (Earth's inner core, a silicate mantle crystallizing from a magma ocean, or an ice shell surrounding a deep water ocean) a convecting crystalline layer is in contact with a layer of its melt. Allowing for melting/freezing at one or both of the boundaries of the solid layer is likely to affect the pattern of convection in the layer. We study here the onset of thermal convection in a viscous spherical shell with dynamically induced melting/freezing at either or both of its boundaries. It is shown that the behavior of each interface depends on the value of a dimensional number P, which is the ratio of a melting/freezing timescale over a viscous relaxation timescale. A small value of P corresponds to permeable boundary conditions, while a large value of P corresponds to impermeable boundary conditions. The linear stability analysis predicts a significant effect of semi-permeable boundaries when the number P characterizing either of the boundary is small enough...