Sample records for mixed-phase cloud microphysics

  1. On the Microphysical Representation of Observed Arctic Mixed-Phase Clouds

    E-Print Network [OSTI]

    Zuidema, Paquita

    On the Microphysical Representation of Observed Arctic Mixed-Phase Clouds Paquita Zuidema, Paul Lawson, Hugh Morrison U of Miami/SPEC, Inc. Boulder CO/NCAR #12;Arctic clouds are often: mixed-phase (ie. both ice + supercooled water) yet long-lasting (despite disequilibrium) #12;why? - are ice nuclei over

  2. FINAL REPORT: An Investigation of the Microphysical, Radiative, and Dynamical Properties of Mixed-Phase Clouds

    SciTech Connect (OSTI)

    Shupe, Matthew D

    2007-10-01T23:59:59.000Z

    This final report summarizes the major accomplishments and products resulting from a three-year grant funded by the DOE, Office of Science, Atmospheric Radiation Measurement Program titled: An Investigation of the Microphysical, Radiative, and Dynamical Properties of Mixed-Phase Clouds. Accomplishments are listed under the following subcategories: Mixed-phase cloud retrieval method development; Mixed-phase cloud characterization; ARM mixed-phase cloud retrieval review; and New ARM MICROBASE product. In addition, lists are provided of service to the Atmospheric Radiation Measurement Program, data products provided to the broader research community, and publications resulting from this grant.

  3. Microphysical Properties of Single and Mixed-Phase Arctic Clouds Derived from AERI Observations

    SciTech Connect (OSTI)

    Turner, David D.

    2003-06-01T23:59:59.000Z

    A novel new approach to retrieve cloud microphysical properties from mixed-phase clouds is presented. This algorithm retrieves cloud optical depth, ice fraction, and the effective size of the water and ice particles from ground-based, high-resolution infrared radiance observations. The theoretical basis is that the absorption coefficient of ice is stronger than that of liquid water from 10-13 mm, whereas liquid water is more absorbing than ice from 16-25 um. However, due to strong absorption in the rotational water vapor absorption band, the 16-25 um spectral region becomes opaque for significant water vapor burdens (i.e., for precipitable water vapor amounts over approximately 1 cm). The Arctic is characterized by its dry and cold atmosphere, as well as a preponderance of mixed-phase clouds, and thus this approach is applicable to Arctic clouds. Since this approach uses infrared observations, cloud properties are retrieved at night and during the long polar wintertime period. The analysis of the cloud properties retrieved during a 7 month period during the Surface Heat Budget of the Arctic (SHEBA) experiment demonstrates many interesting features. These results show a dependence of the optical depth on cloud phase, differences in the mode radius of the water droplets in liquid-only and mid-phase clouds, a lack of temperature dependence in the ice fraction for temperatures above 240 K, seasonal trends in the optical depth with the clouds being thinner in winter and becoming more optically thick in the late spring, and a seasonal trend in the effective size of the water droplets in liquid-only and mixed-phase clouds that is most likely related to aerosol concentration.

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

    SciTech Connect (OSTI)

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

    2007-12-14T23:59:59.000Z

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

  5. 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.

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

    SciTech Connect (OSTI)

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

    2007-09-30T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    Liu, X; Ghan, SJ; Xie, S

    2007-04-01T23:59:59.000Z

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

  8. 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.

  9. 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.

  10. 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.

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

    SciTech Connect (OSTI)

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

    2009-02-02T23:59:59.000Z

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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    E-Print Network [OSTI]

    Solomon, Amy

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

  17. Evaluation of Mixed-Phase Cloud Parameterizations in Short-Range Weather Forecasts with CAM3 and AM2 for Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

    Xie, S; Boyle, J; Klein, S; Liu, X; Ghan, S

    2007-06-01T23:59:59.000Z

    By making use of the in-situ data collected from the recent Atmospheric Radiation Measurement Mixed-Phase Arctic Cloud Experiment, we have tested the mixed-phase cloud parameterizations used in the two major U.S. climate models, the National Center for Atmospheric Research Community Atmosphere Model version 3 (CAM3) and the Geophysical Fluid Dynamics Laboratory climate model (AM2), under both the single-column modeling framework and the U.S. Department of Energy Climate Change Prediction Program-Atmospheric Radiation Measurement Parameterization Testbed. An improved and more physically based cloud microphysical scheme for CAM3 has been also tested. The single-column modeling tests were summarized in the second quarter 2007 Atmospheric Radiation Measurement metric report. In the current report, we document the performance of these microphysical schemes in short-range weather forecasts using the Climate Chagne Prediction Program Atmospheric Radiation Measurement Parameterizaiton Testbest strategy, in which we initialize CAM3 and AM2 with realistic atmospheric states from numerical weather prediction analyses for the period when Mixed-Phase Arctic Cloud Experiment was conducted.

  18. arm mixed-phase arctic: Topics by E-print Network

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

    surface energy budget. However, the treatment of mixed-phase clouds in most current climate models is crude because the detailed microphysical processes involved in mixed-phase...

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

    E-Print Network [OSTI]

    Shupe, Matthew

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

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

    SciTech Connect (OSTI)

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

    2005-03-18T23:59:59.000Z

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

  1. The dependence of ice microphysics on aerosol concentration in...

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

    The dependence of ice microphysics on aerosol concentration in arctic mixed-phase stratus clouds during ISDAC and M-PACE. The dependence of ice microphysics on aerosol...

  2. P2.11 AN ANNUAL CYCLE OF ARCTIC CLOUD MICROPHYSICS Matthew D. Shupe*

    E-Print Network [OSTI]

    Shupe, Matthew

    to classify cloud scenes as all- ice, all-liquid, mixed-phase, or precipitating so that the appropriate ice/snow-covered surfaces. Several studies have demonstrated the importance of specific cloud microphysical properties on cloud-radiation and ice-albedo feedback mechanisms; these in turn have bearing

  3. 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

  4. Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment

    SciTech Connect (OSTI)

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

    2005-03-18T23:59:59.000Z

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

  5. 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

  6. Retrievals of mixed-phase cloud properties during the National Polar-Orbiting Operational Environmental

    E-Print Network [OSTI]

    Liou, K. N.

    Retrievals of mixed-phase cloud properties during the National Polar-Orbiting Operational/Visible Infrared Imaging Radiometer Suite (VIIRS) to retrieve pixel-level mixed-phase cloud optical thicknesses Satellite Observations Validation Project (C3VP), were analyzed. The performance of the mixed-phase

  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. ARM - Field Campaign - Mixed-Phase Arctic Cloud 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- Polarization Diversity Lidar (PDL)govCampaignsMixed-Phase Arctic Cloud Experiment

  9. A Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform Clouds

    E-Print Network [OSTI]

    Eloranta, Edwin W.

    freezing in a mixed-phase stratiform cloud. Immersion freez- ing is represented using a parameterization, and the larger droplets nucleate into ice particles through the immersion freezing process. In mixed-phaseA Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform

  10. Parameterizations of Cloud Microphysics and Indirect Aerosol Effects

    SciTech Connect (OSTI)

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

    2014-05-19T23:59:59.000Z

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

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

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

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

  12. Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighandSWPA / SPRA / USACE625DataNeutrinoMissionMissionJenningsMixed-Phase

  13. 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.

  14. 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

  15. Parameterization of the Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds during the ISDAC Field Campaign

    SciTech Connect (OSTI)

    Korolev, A; Shashkov, A; Barker, H

    2012-03-06T23:59:59.000Z

    This report documents the history of attempts to directly measure cloud extinction, the current measurement device known as the Cloud Extinction Probe (CEP), specific problems with direct measurement of extinction coefficient, and the attempts made here to address these problems. Extinction coefficient is one of the fundamental microphysical parameters characterizing bulk properties of clouds. Knowledge of extinction coefficient is of crucial importance for radiative transfer calculations in weather prediction and climate models given that Earth's radiation budget (ERB) is modulated much by clouds. In order for a large-scale model to properly account for ERB and perturbations to it, it must ultimately be able to simulate cloud extinction coefficient well. In turn this requires adequate and simultaneous simulation of profiles of cloud water content and particle habit and size. Similarly, remote inference of cloud properties requires assumptions to be made about cloud phase and associated single-scattering properties, of which extinction coefficient is crucial. Hence, extinction coefficient plays an important role in both application and validation of methods for remote inference of cloud properties from data obtained from both satellite and surface sensors (e.g., Barker et al. 2008). While estimation of extinction coefficient within large-scale models is relatively straightforward for pure water droplets, thanks to Mie theory, mixed-phase and ice clouds still present problems. This is because of the myriad forms and sizes that crystals can achieve, each having their own unique extinction properties. For the foreseeable future, large-scale models will have to be content with diagnostic parametrization of crystal size and type. However, before they are able to provide satisfactory values needed for calculation of radiative transfer, they require the intermediate step of assigning single-scattering properties to particles. The most basic of these is extinction coefficient, yet it is rarely measured directly, and therefore verification of parametrizations is difficult. The obvious solution is to be able to measure microphysical properties and extinction at the same time and for the same volume. This is best done by in situ sampling by instruments mounted on either balloon or aircraft. The latter is the usual route and the one employed here. Yet the problem of actually measuring extinction coefficient directly for arbitrarily complicated particles still remains unsolved.

  16. 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

  17. 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.

  18. 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

  19. Atmospheric State, Cloud Microphysics and Radiative Flux

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

    Mace, Gerald

    Atmospheric thermodynamics, cloud properties, radiative fluxes and radiative heating rates for the ARM Southern Great Plains (SGP) site. The data represent a characterization of the physical state of the atmospheric column compiled on a five-minute temporal and 90m vertical grid. Sources for this information include raw measurements, cloud property and radiative retrievals, retrievals and derived variables from other third-party sources, and radiative calculations using the derived quantities.

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

    SciTech Connect (OSTI)

    Greg M. McFarquhar

    2010-02-22T23:59:59.000Z

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

  1. THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS AND ANVIL

    E-Print Network [OSTI]

    THE ROLE OF CLOUD MICROPHYSICS PARAMETERIZATION IN THE SIMULATION OF MESOSCALE CONVECTIVE SYSTEMS in the Simulation of Mesoscale Convective Systems and Anvil Clouds in the Tropical Western Pacific K. Van Weverberg1 cloud microphysics in the simulation of mesoscale convective systems (MCSs) in the tropical western

  2. Cloud optical and microphysical properties derived from ground-based and satellite sensors over

    E-Print Network [OSTI]

    Li, Zhanqing

    Cloud optical and microphysical properties derived from ground-based and satellite sensors over of cloud optical and microphysical properties were made at Taihu, a highly polluted site in the central Yangtze Delta region, during a research campaign from May 2008 to December 2009. Cloud optical depth (COD

  3. Using Surface Remote Sensors to Derive Radiative Characteristics of Mixed-Phase Clouds: An Example from M-PACE

    SciTech Connect (OSTI)

    de Boer, Gijs; Collins, William D.; Menon, Surabi; Long, Charles N.

    2011-12-02T23:59:59.000Z

    Measurements from ground-based cloud radar, high spectral resolution lidar and microwave radiometer are used in conjunction with a column version of the Rapid Radiative Transfer Model (RRTMG) and radiosonde measurements to derive the surface radiative properties under mixed-phase cloud conditions. These clouds were observed during the United States Department of Energy (US DOE) Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment (M-PACE) between September and November of 2004. In total, sixteen half hour time periods are reviewed due to their coincidence with radiosonde launches. Cloud liquid (ice) water paths are found to range between 11.0-366.4 (0.5-114.1) gm-2, and cloud physical thicknesses fall between 286-2075 m. Combined with temperature and hydrometeor size estimates, this information is used to calculate surface radiative flux densities using RRTMG, which are demonstrated to generally agree with measured flux densities from surface-based radiometric instrumentation. Errors in longwave flux density estimates are found to be largest for thin clouds, while shortwave flux density errors are generally largest for thicker clouds. A sensitivity study is performed to understand the impact of retrieval assumptions and uncertainties on derived surface radiation estimates. Cloud radiative forcing is calculated for all profiles, illustrating longwave dominance during this time of year, with net cloud forcing generally between 50 and 90 Wm-2.

  4. JP2.3 CLOUD RADIATIVE HEATING RATE FORCING FROM PROFILES OF RETRIEVED ARCTIC CLOUD MICROPHYSICS

    E-Print Network [OSTI]

    Shupe, Matthew

    JP2.3 CLOUD RADIATIVE HEATING RATE FORCING FROM PROFILES OF RETRIEVED ARCTIC CLOUD MICROPHYSICS surface. In 1997-1998, a large multi-agency effort made the Surface Heat Budget of the Arctic (SHEBA with the ice pack in the Beaufort and Chukchi Seas for one year. Surface-based remote sensors generated

  5. On the Microphysical Properties of Ice Clouds as Inferred from the Polarization of Electromagnetic Waves

    E-Print Network [OSTI]

    Cole, Benjamin

    2012-10-19T23:59:59.000Z

    Uncertainties associated with the microphysical and radiative properties of ice clouds remain an active research area because of the importance these clouds have in atmospheric radiative transfer problems and the energy balance of the Earth...

  6. On the Microphysical Properties of Ice Clouds as Inferred from the Polarization of Electromagnetic Waves 

    E-Print Network [OSTI]

    Cole, Benjamin

    2012-10-19T23:59:59.000Z

    Uncertainties associated with the microphysical and radiative properties of ice clouds remain an active research area because of the importance these clouds have in atmospheric radiative transfer problems and the energy balance of the Earth...

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

    SciTech Connect (OSTI)

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

    2012-09-28T23:59:59.000Z

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

  8. DOE/SC-ARM-P-07-006 Evaluation of Mixed-Phase Cloud Microphysics

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration wouldDECOMPOSITION OF CALCIUMCOSTDOENuclear1382 THEDOE0-354-1502 ARM63173006

  9. Microphysical Properties of Single and Mixed-Phase Arctic Clouds Derived from AERI Observations

    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 fromprocess usedGE ResearchersIndustrial| The

  10. Continuous Profiles of Cloud Microphysical Properties for the Fixed Atmospheric Radiation Measurement Sites

    SciTech Connect (OSTI)

    Jensen, M; Jensen, K

    2006-06-01T23:59:59.000Z

    The Atmospheric Radiation Measurement (ARM) Program defined a specific metric for the third quarter of Fiscal Year 2006 to produce and refine a one-year continuous time series of cloud microphysical properties based on cloud radar measurements for each of the fixed ARM sites. To accomplish this metric, we used a combination of recently developed algorithms that interpret radar reflectivity profiles, lidar backscatter profiles, and microwave brightness temperatures into the context of the underlying cloud microphysical structure.

  11. 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

  12. Indian Summer Monsoon Drought 2009: Role of Aerosol and Cloud Microphysics

    SciTech Connect (OSTI)

    Hazra, Anupam; Taraphdar, Sourav; Halder, Madhuparna; Pokhrel, S.; Chaudhari, H. S.; Salunke, K.; Mukhopadhyay, P.; Rao, S. A.

    2013-07-01T23:59:59.000Z

    Cloud dynamics played a fundamental role in defining Indian summer monsoon (ISM) rainfall during drought in 2009. The anomalously negative precipitation was consistent with cloud properties. Although, aerosols inhibited the growth of cloud effective radius in the background of sparse water vapor, their role is secondary. The primary role, however, is played by the interactive feedback between cloud microphysics and dynamics owing to reduced efficient cloud droplet growth, lesser latent heating release and shortage of water content. Cloud microphysical processes were instrumental for the occurrence of ISM drought 2009.

  13. 1 DECEMBER 1995 Validation of Satellite Retrievals of Cloud Microphysics and Liquid Water Path

    E-Print Network [OSTI]

    Han, Quingyuan

    1 DECEMBER 1995 Validation of Satellite Retrievals of Cloud Microphysics and Liquid Water Path Using Observations from FIRE 1, Introduction Q. HAN, * W. Rossow, t R. WELCH, * A. WHITE, * * AND J Cloud effective radii (r) and cloud liquid water path (LWP) are derived from ISCCP spatially sampled

  14. Quantifying uncertainties of cloud microphysical property retrievals with a perturbation method

    E-Print Network [OSTI]

    Ohta, Shigemi

    to their modification effects on global radiation balance and atmospheric water cycle. However, representation of clouds Radiation Measurement (ARM) facility, whose primary goal is to carry out long-term observations of cloudsQuantifying uncertainties of cloud microphysical property retrievals with a perturbation method

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

    SciTech Connect (OSTI)

    Bennartz, Ralf; Hamilton, Kevin P; Phillips, Vaughan T.J.; Wang, Yuqing; Brenguier, Jean-Louis

    2013-01-14T23:59:59.000Z

    The three top-level project goals are: -We proposed to develop, test, and run a new, physically based, scale-independent microphysical scheme for those cloud processes that most strongly affect greenhouse gas scenarios, i.e. warm cloud microphysics. In particular, we propsed to address cloud droplet activation, autoconversion, and accretion. -The new, unified scheme was proposed to be derived and tested using the University of Hawaii's IPRC Regional Atmospheric Model (iRAM). -The impact of the new parameterizations on climate change scenarios will be studied. In particular, the sensitivity of cloud response to climate forcing from increased greenhouse gas concentrations will be assessed.

  16. 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.

  17. 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.

  18. Microphysical and Dynamical Influences on Cirrus Cloud Optical Depth Distributions

    SciTech Connect (OSTI)

    Kay, J.; Baker, M.; Hegg, D.

    2005-03-18T23:59:59.000Z

    Cirrus cloud inhomogeneity occurs at scales greater than the cirrus radiative smoothing scale ({approx}100 m), but less than typical global climate model (GCM) resolutions ({approx}300 km). Therefore, calculating cirrus radiative impacts in GCMs requires an optical depth distribution parameterization. Radiative transfer calculations are sensitive to optical depth distribution assumptions (Fu et al. 2000; Carlin et al. 2002). Using raman lidar observations, we quantify cirrus timescales and optical depth distributions at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Lamont, OK (USA). We demonstrate the sensitivity of outgoing longwave radiation (OLR) calculations to assumed optical depth distributions and to the temporal resolution of optical depth measurements. Recent work has highlighted the importance of dynamics and nucleation for cirrus evolution (Haag and Karcher 2004; Karcher and Strom 2003). We need to understand the main controls on cirrus optical depth distributions to incorporate cirrus variability into model radiative transfer calculations. With an explicit ice microphysics parcel model, we aim to understand the influence of ice nucleation mechanism and imposed dynamics on cirrus optical depth distributions.

  19. A06: Analysis of GRAPE data The effects of anthropogenic aerosols on cloud microphysical properties.

    E-Print Network [OSTI]

    Oxford, University of

    the radiative balance of the atmosphere. This effect is known as the `first direct radiative forcing'[4 of this warming is to reduce the upward movement of moisture and in turn reduce the cloud cover[5]. This `semiA06: Analysis of GRAPE data The effects of anthropogenic aerosols on cloud microphysical properties

  20. Radiative and microphysical properties of Arctic stratus clouds from multiangle downwelling infrared radiances

    E-Print Network [OSTI]

    Shupe, Matthew

    climate is strongly influenced by an extensive and persistent pattern of cloud cover [Francis, 1997 properties can have significant effects on long- wave radiation, which dominates the radiation energy budgetRadiative and microphysical properties of Arctic stratus clouds from multiangle downwelling

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

    SciTech Connect (OSTI)

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

    2013-11-26T23:59:59.000Z

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

  2. Analysis of In situ Observations of Cloud Microphysics from M-PACE Final Report, DOE Grant Agreement No. DE-FG02-06ER64168

    SciTech Connect (OSTI)

    Michael R. Poellot

    2009-01-09T23:59:59.000Z

    This report summarizes the findings and accomplishments of work performed under DOE Grant Agreement No. DE-FG02-06ER64168. The focus of the work was the analysis of in situ observations collected by the University of North Dakota Citation research aircraft during the Mixed-Phase Arctic Cloud Experiment (M-PACE). This project was conducted in 2004 along the North Slope of Alaska. The objectives of the research were: to characterize certain microphysical properties of clouds sampled during M-PACE, including spatial variability, precipitation formation, ice multiplication; to examine instrument performance and certain data processing algorithms; and to collaborate with other M-PACE investigators on case study analyses. A summary of the findings of the first two objectives is given here in parts 1 and 2; full results are contained in reports listed in part 3 of this report. The collaborative efforts are described in the publications listed in part 3.

  3. 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

  4. Cloud top microphysics as a tool for precipitation measurements Daniel Rosenfeld, Hebrew University of Jerusalem, Jerusalem, Israel

    E-Print Network [OSTI]

    Daniel, Rosenfeld

    Cloud top microphysics as a tool for precipitation measurements Daniel Rosenfeld, Hebrew University typically comes from the cloud droplets and ice particles near the cloud tops, with little to the cloud top temperatures and its type, i.e., convective or stratiform. However, precipitation in clouds

  5. The Microbase Value-Added Product: A Baseline Retrieval of Cloud Microphysical Properties

    SciTech Connect (OSTI)

    Dunn, M; Johnson, K; Jensen, M

    2011-05-31T23:59:59.000Z

    This report describes the Atmospheric Radiation Measurement (ARM) Climate Research Facility baseline cloud microphysical properties (MICROBASE) value-added product (VAP). MICROBASE uses a combination of millimeter-wavelength cloud radar, microwave radiometer, and radiosonde observations to estimate the vertical profiles of the primary microphysical parameters of clouds including the liquid/ice water content and liquid/ice cloud particle effective radius. MICROBASE is a baseline algorithm designed to apply to most conditions and locations using a single set of parameterizations and a simple determination of water phase based on temperature. This document provides the user of this product with guidelines to assist in determining the accuracy of the product under certain conditions. Quality control flags are designed to identify outliers and indicate instances where the retrieval assumptions may not be met. The overall methodology is described in this report through a detailed description of the input variables, algorithms, and output products.

  6. Mixed-phase clouds, thin cirrus clouds, and OLR over the tropics: observations, retrievals, and radiative impacts

    E-Print Network [OSTI]

    Lee, Joonsuk

    2009-06-02T23:59:59.000Z

    to the inference of effective particle sizes and optical thicknesses are performed. Errors are calculated with respect to the assumption of a cloud containing solely liquid or ice phase particles. The analyses suggest that the effective particle size inferred for a...

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

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

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

  8. OAK 270 - The use of Lidar/radiometer (LIRAD) in the ARM program to obtain optical properties and microphysics of high and midlevel clouds

    SciTech Connect (OSTI)

    C.M.R. Platt; R.T. Austin; S.A. Young; and G.L. Stephens

    2002-12-13T23:59:59.000Z

    OAK 270 - The use of Lidar/Radiometer (LIRAD) in the ARM program to obtain optical properties and microphysics of high and midlevel clouds

  9. 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

  10. ISDAC Microphysics

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

    McFarquhar, Greg

    Best estimate of cloud microphysical parameters derived using data collected by the cloud microphysical probes installed on the National Research Council (NRC) of Canada Convair-580 during ISDAC. These files contain phase, liquid and ice crystal size distributions (Nw(D) and Ni(D) respectively), liquid water content (LWC), ice water content (IWC), extinction of liquid drops (bw), extinction of ice crystals (bi), effective radius of water drops (rew) and of ice crystals (rei) and median mass diameter of liquid drops (Dmml) and of ice crystals (Dmmi) at 30 second resolution.

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

    SciTech Connect (OSTI)

    Wang, Zhien

    2010-06-29T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    McFarquhar, Greg

    2012-09-19T23:59:59.000Z

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

  13. 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

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

    E-Print Network [OSTI]

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

    2013-01-01T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    J. O. Pinto, A.H. Lynch

    2005-12-14T23:59:59.000Z

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

  16. The microphysical effects of stochastic coalescence on an initially-steady, one-dimensional, adiabatic cloud

    E-Print Network [OSTI]

    Jorgensen, David Paul

    1974-01-01T23:59:59.000Z

    of the cumulus. Studies have indicated that the growth and subsequent fallout of precipita- tion interacts with the updraft, which in turn controls the growth of droplets (Mason, 1969). Indeed, as pointed out by Das (1969), precipitation formation can also... be specified by the following questions: (1) What is the role of condensation microphysics in cumulus dynamics, i. e. , what de- partures are expected if condensation in the updraft is computed directly from the physics of condensation on nuclei and droplets...

  17. 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

    The research presented here retrieves the cloud optical thickness and particle effective size of cirrus clouds using surface radiation measurements obtained during the Atmospheric Radiation Measurement (ARM) field campaign. The algorithm used...

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

    SciTech Connect (OSTI)

    Heymsfield, A.

    1997-09-01T23:59:59.000Z

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

  19. Black carbon radiative heating effects on cloud microphysics and implications for the aerosol indirect

    E-Print Network [OSTI]

    Nenes, Athanasios

    thought. 1. Introduction Black Carbon (BC) has important effects on climate, owing to its ability of Technology, Pasadena, California, 91125, USA Abstract. This work examines the effect of black carbon (BC) radiative heating on cloud droplet formation. Changes in cloud droplet concentration and cloud albedo due

  20. Ice cloud microphysics retrievals from millimeter radar and visible optical depth using an estimation theory approach

    E-Print Network [OSTI]

    Stephens, Graeme L.

    of the planet. These effects occur as a consequence of the way cloud particles scatter and absorb radiation, 0325); 1655 Global Change: Water cycles (1836); KEYWORDS: ice water content retrieval, cirrus cloud), 4335, doi:10.1029/2002JD002693, 2003. 1. Introduction [2] Clouds profoundly affect the radiation budget

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

    SciTech Connect (OSTI)

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

    2014-12-27T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

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

    2005-03-18T23:59:59.000Z

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

  3. 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...

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

    SciTech Connect (OSTI)

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

    2003-06-11T23:59:59.000Z

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

  5. FINAL REPORT FOR THE DOE/ARM PROJECT TITLED Representation of the Microphysical and Radiative Properties of Ice Clouds in SCMs and GCMs

    SciTech Connect (OSTI)

    Mitchell, David L.

    2005-08-08T23:59:59.000Z

    The broad goal of this research is to improve climate prediction through better representation of cirrus cloud microphysical and radiative properties in global climate models (GCMs). Clouds still represent the greatest source of uncertainty in climate prediction, and the representation of ice clouds is considerably more challenging than liquid water clouds. While about 40% of cloud condensate may be in the form of ice by some estimates, there have been no credible means of representing the ice particle size distribution and mass removal rates from ice clouds in GCMs. Both factors introduce large uncertainties regarding the global net flux, the latter factor alone producing a change of 10 W/m2 in the global net flux due to plausible changes in effective ice particle fallspeed. In addition, the radiative properties of ice crystals themselves are in question. This research provides GCMs with a credible means of representing the full (bimodal) ice particle size distribution (PSD) in ice clouds, including estimates of the small crystal (D < 65 microns) mode of the PSD. It also provides realistic estimates of mass sedimentation rates from ice clouds, which have a strong impact on their ice contents and radiative properties. This can be done through proper analysis of ice cloud microphysical data from ARM and other field campaigns. In addition, this research tests the ice cloud radiation treatment developed under two previous ARM projects by comparing it against laboratory measurements of ice cloud extinction efficiency and by comparing it with explicit theoretical calculations of ice crystal optical properties. The outcome of this project includes two PSD schemes for ice clouds; one appropriate for mid-latitude cirrus clouds and another for tropical anvil cirrus. Cloud temperature and ice water content (IWC) are the inputs for these PSD schemes, which are based on numerous PSD observations. The temperature dependence of the small crystal mode of the PSD for tropical anvils is opposite to that of mid-latitude cirrus, and this results in very different radiative properties for these two types of cirrus at temperatures less than about 50 C for a given ice water path. In addition, the representative PSD fall velocity is strongly influenced by the small crystal mode, and for temperatures less than 52 C, this fall velocity for mid-latitude cirrus is 2-8 times greater than for tropical anvil cirrus. Finally, the treatment of ice cloud optical properties was found to agree with laboratory measurements and exact theory within 15% for any given wavelength, PSD and ice particle shape. This treatment is analytical, formulated in terms of the PSD and ice particle shape properties. It thus provides the means for explicitly coupling the ice cloud microphysical and radiative properties, and can treat any combination of ice particle shape. It is very inexpensive regarding computer time. When these three deliverables were incorporated into the GCM at the National Center for Atmospheric Research (NCAR) under another project, it was found that the sunlight reflected and the amount of upwelling heat absorbed by cirrus clouds depended strongly on the PSD scheme used (i.e. mid-latitude or tropical anvil). This was largely due to the fall velocities associated with the two PSD schemes, although the PSD shape was also important.

  6. 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.

  7. In-Situ Microphysics from the MPACE IOP

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

    McFarquhar, Greg

    Best estimates of the size distributions of supercooled water droplets and ice crystals for mixed-phase clouds measured during M-PACE for spiral ascents/descents over Barrow and Oliktok Point, and for ramped ascents/descents between Barrow and Oliktok Point. Our best estimates of the bulk microphysical properties such as ice water content (IWC), liquid water content (LWC), effective radius of ice crystals defined following Fu (1996) (rei), effective radius of supercooled water droplets (rew), total ice crystal number concentration (Ni), total water droplet number concentration (Nw) and total condensed water content (CWC), are also provided. The quantities were derived from the FSSP, 1DC, 2DC, HVPS and the CVI. Note HVPS data are only available after 10 Oct 2004 and some procedures have been developed to account for the missing data.

  8. Collaborative Research: The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change

    SciTech Connect (OSTI)

    Dr. Kerry Emanuel; Michael J. Iacono

    2011-06-28T23:59:59.000Z

    Uncertainties in representing the atmospheric water cycle are major obstacles to an accurate prediction of future climate. This project focused on addressing some of these uncertainties by implementing new physics for convection and radiation into the NCAR climate model. To better understand and eventually better represent these processes, we modified CAM3.5 to use the convection and cloud schemes developed by the Massachusetts Institute of Technology (MIT) and the RRTMG rapid radiation code for global models developed by Atmospheric and Environmental Research, Inc. (AER). The impact of the new physics on the CAM3.5 simulation of convection on diurnal and intra-seasonal scales, intra-seasonal oscillations and the distribution of water vapor has been investigated. The effect of the MIT and AER physics also has been tested in the Weather Research and Forecasting (WRF) regional forecast model. It has been found that the application of the AER radiation and MIT convection produces significant improvements in the modeled diurnal cycle of convection, especially over land, in the NCAR climate model. However, both the standard CAM3.5 (hereinafter STD) and the modified CAM3.5 with the new physics (hereinafter MOD) are still unable to capture the proper spectrum and propagating characteristics of the intra-seasonal oscillations (ISOs). The new physics methods modify, but do not substantially improve, the distribution of upper tropospheric water vapor relative to satellite measurements.

  9. The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change

    SciTech Connect (OSTI)

    Emanuel, Kerry; Iacono, Michael J.

    2010-11-11T23:59:59.000Z

    Uncertainties in representing the atmospheric water cycle are major obstacles to the accurate prediction of future climate. This project focused on addressing some of these uncertainties by implementing new physics for convection and radiation into the NCAR Community Atmosphere Model (CAM). To better understand and eventually better represent these processes in this major national climate model, we modified CAM3.5 to use the convection and cloud schemes developed by the Massachusetts Institute of Technology (MIT) and the RRTMG rapid radiation code for global climate models developed by Atmospheric and Environmental Research, Inc. (AER). The impact of the new physics on the CAM3.5 simulation of convection on diurnal and intra-seasonal scales, on intra-seasonal oscillations and on the distribution of water vapor has been investigated. In addition, the MIT and AER physics packages have been incorporated and tested in combination within the Weather Research and Forecasting (WRF) regional forecast model for the purpose of evaluating and improving convective and radiative processes on time scales appropriate to weather simulations. It has been found that the application of the AER radiation and MIT convection produces significant improvements in the modeled diurnal cycle of convection, especially over land, in the NCAR climate model. However, both the standard CAM3.5 and the modified CAM3.5 with the new physics are unable to capture the proper spectrum and propagating characteristics of dynamical intra-seasonal oscillations such as the Madden-Julian Oscillation. In addition, it has been shown that the new physics methods modify, but do not substantially improve, the distribution of upper tropospheric water vapor in CAM as established through the comparison of modeled and observed satellite radiances. This suggests that continuing regional discrepancies in water vapor amounts in the climate model may not be solely related to convective or radiative processes. The major results of this project have been described in more detail in a journal article titled â??The Impacts of AER Radiation and MIT Convection on the Water Cycle Simulated by CAM3.5â?ť that will be submitted for publication during Fall 2010.

  10. 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

  11. The effect of ice crystal surface roughness on the retrieval of ice cloud microphysical and optical properties 

    E-Print Network [OSTI]

    Xie, Yu

    2007-09-17T23:59:59.000Z

    on the retrieval of ice cloud effective particle size, optical thickness and cloud-top temperature. Three particle surface conditions, smooth, moderately rough and deeply rough, are considered in the visible and near-infrared channels (0.65 and 3.75 Ă...

  12. The effect of ice crystal surface roughness on the retrieval of ice cloud microphysical and optical properties

    E-Print Network [OSTI]

    Xie, Yu

    2007-09-17T23:59:59.000Z

    The effect of the surface roughness of ice crystals is not routinely accounted for in current cloud retrieval algorithms that are based on pre-computed lookup libraries. In this study, we investigate the effect of ice crystal surface roughness...

  13. 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.

  14. 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.

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

    SciTech Connect (OSTI)

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

    2010-09-28T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

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

    2013-11-08T23:59:59.000Z

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

  17. Parameterizing Size Distribution in Ice Clouds

    SciTech Connect (OSTI)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

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

    2011-11-13T23:59:59.000Z

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

  19. Chapter Three Thermodynamics, Cloud Microphysics

    E-Print Network [OSTI]

    Xue, Ming

    ­lasting convection. Ice phase is currently not present in the model. The inclusion of it would in general change source and sink. However models without ice phase are still able to capture the essential dynamics systems such as mesoscale convective rainbands and squall lines, phase changes of water occur as mesoscale

  20. Chapter Three Thermodynamics, Cloud Microphysics

    E-Print Network [OSTI]

    Xue, Ming

    and the evaporative cooling induced downdraught plays a key role in organizing long-lasting convection. Ice phase. However models without ice phase are still able to capture the essential dynamics of some convective such as mesoscale convective rainbands and squall lines, phase changes of water occur as mesoscale and/or subgrid

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

    E-Print Network [OSTI]

    Li, Jun

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

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

    E-Print Network [OSTI]

    Gettelman, Andrew

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

  3. Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics

    E-Print Network [OSTI]

    He, Q.

    2011-01-01T23:59:59.000Z

    Controllable Spontaneous Magnetism in Nanoscale Mixed Phase2001). Chakhalian, J. et al. Magnetism at the interfacelocal nature of this magnetism. We find that the spontaneous

  4. A numerical model of aerosol scavenging: Part 1, Microphysics parameterization

    SciTech Connect (OSTI)

    Molenkamp, C.R.; Bradley, M.M.

    1991-09-01T23:59:59.000Z

    We have developed a three-dimensional numerical model (OCTET) to simulate the dynamics and microphysics of clouds and the transport, diffusion and precipitation scavenging of aerosol particles. In this paper we describe the cloud microphysics and scavenging parameterizations. The representation of cloud microphysics is a bulk- water parameterization which includes water vapor and five types of hydrometeors (cloud droplets, rain drops, ice crystals, snow, and graupel). A parallel parameterization represents the scavenging interactions between pollutant particles and hydrometeors including collection of particles because of condensation nucleation, Brownian and phoretic attachment, and inertial capture, resuspension because of evaporation and sublimation; and transfer interactions where particles collected by one type of hydrometeor are transferred to another type of freezing, melting, accretion, riming and autoconversion.

  5. Towards a Characterization of Arctic Mixed-Phase 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 Spin Transition in2, 2003Tool ofTopo II:7.1 7.0 8.04.2o

  6. Simulating Arctic mixed-phase clouds: Sensitivity to environmental

    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 and Media

  7. The Mixed Phase of Charged AdS Black holes

    E-Print Network [OSTI]

    Piyabut Burikham; Chatchai Promsiri

    2015-01-20T23:59:59.000Z

    We study the mixed phase of charged AdS black hole and radiation when the total energy is fixed below the threshold to produce a stable charged black hole branch. The coexistence conditions for the charged AdS black hole and radiation are derived for the generic case when radiation particles carry charge. The phase diagram of the mixed phase is demonstrated for both fixed potential and charge ensemble. In the dual gauge picture, they correspond to the mixed phase of quark-gluon plasma~(QGP) and hadron gas in the fixed chemical potential and density ensemble respectively. In the nuclei and heavy ion collisions at intermediate energies, the mixed phase of exotic QGP and hadron gas could be produced. The mixed phase will condensate and evaporate into the hadron gas as the fireball expands.

  8. Tellus (1989), 41A, 132-147 The effect of parameterized ice microphysics on the

    E-Print Network [OSTI]

    Zhang, Da-Lin

    Tellus (1989), 41A, 132-147 The effect of parameterized ice microphysics on the simulation and associated stratiform rainfall. In this paper, parameterized cloud ice and snow crystals are incorporated on a grid resolution of 25 km. With the inclusion of ice microphysics parameterization. the resolvable

  9. 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.

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

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

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

  11. Combined Retrieval, Microphysical Retrievals and Heating Rates

    SciTech Connect (OSTI)

    Feng, Zhe

    2013-02-22T23:59:59.000Z

    Microphysical retrievals and heating rates from the AMIE/Gan deployment using the PNNL Combined Retrieval.

  12. Combined Retrieval, Microphysical Retrievals and Heating Rates

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

    Feng, Zhe

    Microphysical retrievals and heating rates from the AMIE/Gan deployment using the PNNL Combined Retrieval.

  13. Atomic oxygen flux determined by mixed-phase Ag/Ag2O deposition...

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

    oxygen flux determined by mixed-phase AgAg2O deposition. Atomic oxygen flux determined by mixed-phase AgAg2O deposition. Abstract: The flux of atomic oxygen generated in a...

  14. Cloud Microphysics Spring 2013 **odd years?**

    E-Print Network [OSTI]

    electrification theories. Instructors: Sonia Kreidenweis, Professor, Department of Atmosphic Science Sue van den Heever, Assistant Professor, Department of Atmospheric Science Text(s): **Sonia and Sue, please complete

  15. Posters Cloud Microphysical and Radiative Properties Measured

    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 observations71 Posters117

  16. Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects

    SciTech Connect (OSTI)

    Wang, Yuan; Fan, Jiwen; Zhang, Renyi; Leung, Lai-Yung R.; Franklin, Charmaine N.

    2013-06-05T23:59:59.000Z

    To improve the microphysical parameterizations for simulations of the aerosol indirect effect (AIE) in regional and global climate models, a double-moment bulk microphysical scheme presently implemented in the Weather Research and Forecasting (WRF) model is modified and the results are compared against atmospheric observations and simulations produced by a spectral bin microphysical scheme (SBM). Rather than using prescribed aerosols as in the original bulk scheme (Bulk-OR), a prognostic doublemoment aerosol representation is introduced to predict both the aerosol number concentration and mass mixing ratio (Bulk-2M). The impacts of the parameterizations of diffusional growth and autoconversion and the selection of the embryonic raindrop radius on the performance of the bulk microphysical scheme are also evaluated. Sensitivity modeling experiments are performed for two distinct cloud regimes, maritime warm stratocumulus clouds (SC) over southeast Pacific Ocean from the VOCALS project and continental deep convective clouds (DCC) in the southeast of China from the Department of Energy/ARM Mobile Facility (DOE/AMF) - China field campaign. The results from Bulk-2M exhibit a much better agreement in the cloud number concentration and effective droplet radius in both the SC and DCC cases with those from SBM and field measurements than those from Bulk-OR. In the SC case particularly, Bulk-2M reproduces the observed drizzle precipitation, which is largely inhibited in Bulk-OR. Bulk-2M predicts enhanced precipitation and invigorated convection with increased aerosol loading in the DCC case, consistent with the SBM simulation, while Bulk-OR predicts the opposite behaviors. Sensitivity experiments using four different types of autoconversion schemes reveal that the autoconversion parameterization is crucial in determining the raindrop number, mass concentration, and drizzle formation for warm 2 stratocumulus clouds. An embryonic raindrop size of 40 ?m is determined as a more realistic setting in the autoconversion parameterization. The saturation adjustment employed in calculating condensation/evaporation in the bulk scheme is identified as the main factor responsible for the large discrepancies in predicting cloud water in the SC case, suggesting that an explicit calculation of diffusion growth with predicted supersaturation is necessary for further improvements of the bulk microphysics scheme. Lastly, a larger rain evaporation rate below cloud is found in the bulk scheme in comparison to the SBM simulation, which could contribute to a lower surface precipitation in the bulk scheme.

  17. Study of ice cloud properties using infrared spectral data

    E-Print Network [OSTI]

    Garrett, Kevin James

    2009-05-15T23:59:59.000Z

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

  18. Study of ice cloud properties using infrared spectral data 

    E-Print Network [OSTI]

    Garrett, Kevin James

    2009-05-15T23:59:59.000Z

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

  19. Boundary Circles of Mixed Phase Space, Hamiltonian Systems

    E-Print Network [OSTI]

    Or Alus; Shmuel Fishman; James D. Meiss

    2014-10-28T23:59:59.000Z

    The phase space of an area-preserving map typically contains infinitely many elliptic islands embedded in a chaotic sea. Orbits near the boundary of a chaotic region have been observed to stick for long times, strongly influencing their transport properties. The boundary is composed of invariant circles, called "Boundary circles." We investigate the distribution of rotation numbers of boundary circles for the Henon quadratic map and show that the probability of occurrence of small elements of their continued fraction expansions is larger than would be expected for a number chosen at random. However, large elements occur with probabilities distributed proportionally to the random case. These results have implications for models of transport in mixed phase space.

  20. Modulation of mixed-phase titania photoluminescence by oxygen adsorption

    SciTech Connect (OSTI)

    Pallotti, D.; Orabona, E.; Amoruso, S.; Maddalena, P. [Dipartimento di Fisica, Universitá degli Studi di Napoli “Federico II,” Via Cintia, I-80126 Napoli (Italy); Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Lettieri, S., E-mail: stefano.lettieri@spin.cnr.it [Institute for Superconductors, Oxides and Innovative Materials and Devices, CNR-SPIN, U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy)

    2014-07-21T23:59:59.000Z

    We investigate the effect of oxygen (O{sub 2}) adsorption on photoluminescence properties of mixed-phase titania nanoparticle films deposited by femtosecond pulsed laser deposition, aiming to assess preliminary conclusions about the feasibility of opto-chemical sensing based on titania. We evidence that O{sub 2} produces opposite responses in rutile and anatase photoluminescence efficiency, highlighting interesting potentialities for future double-parametric optical sensing based on titania. The results evidence an important role of lattice oxygen atoms, suggesting that the standard Schottky barrier mechanism driving the response toward gas species in most used metal-oxide sensors (e.g., tin dioxide) is not the only active mechanism in titania.

  1. 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

  2. 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

  3. Investigation of Aerosol Indirect Effects using a Cumulus Microphysics Parameterization in a Regional Climate Model

    SciTech Connect (OSTI)

    Lim, Kyo-Sun; Fan, Jiwen; Leung, Lai-Yung R.; Ma, Po-Lun; Singh, Balwinder; Zhao, Chun; Zhang, Yang; Zhang, Guang; Song, Xiaoliang

    2014-01-29T23:59:59.000Z

    A new Zhang and McFarlane (ZM) cumulus scheme includes a two-moment cloud microphysics parameterization for convective clouds. This allows aerosol effects to be investigated more comprehensively by linking aerosols with microphysical processes in both stratiform clouds that are explicitly resolved and convective clouds that are parameterized in climate models. This new scheme is implemented in the Weather Research and Forecasting (WRF) model, which is coupled with the physics and aerosol packages from the Community Atmospheric Model version 5 (CAM5). A test case of July 2008 during the East Asian summer monsoon is selected to evaluate the performance of the new ZM scheme and to investigate aerosol effects on monsoon precipitation. The precipitation and radiative fluxes simulated by the new ZM scheme show a better agreement with observations compared to simulations with the original ZM scheme that does not include convective cloud microphysics and aerosol convective cloud interactions. Detailed analysis suggests that an increase in detrained cloud water and ice mass by the new ZM scheme is responsible for this improvement. To investigate precipitation response to increased anthropogenic aerosols, a sensitivity experiment is performed that mimics a clean environment by reducing the primary aerosols and anthropogenic emissions to 30% of that used in the control simulation of a polluted environment. The simulated surface precipitation is reduced by 9.8% from clean to polluted environment and the reduction is less significant when microphysics processes are excluded from the cumulus clouds. Ensemble experiments with ten members under each condition (i.e., clean and polluted) indicate similar response of the monsoon precipitation to increasing aerosols.

  4. In-Situ Microphysics from the RACORO IOP

    SciTech Connect (OSTI)

    McFarquhar, Greg

    2013-11-08T23:59:59.000Z

    These files were generated by Greg McFarquhar and Robert Jackson at the University of Illinois. Please contact mcfarq@atmos.uiuc.edu or rjackso2@atmos.uiuc.edu for more information or for assistance in interpreting the content of these files. We highly recommend that anyone wishing to use these files do so in a collaborative endeavor and we welcome queries and opportunities for collaboration. There are caveats associated with the use of the data which are difficult to thoroughly document and not all products for all time periods have been thoroughly examined. This is a value added data set of the best estimate of cloud microphysical parameters derived using data collected by the cloud microphysical probes installed on the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter during RACORO. These files contain best estimates of liquid size distributions N(D) in terms of droplet diameter D, liquid water content LWC, extinction of liquid drops beta, effective radius of cloud drops (re), total number concentration of droplets NT, and radar reflectivity factor Z at 1 second resolution.

  5. In-Situ Microphysics from the RACORO IOP

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

    McFarquhar, Greg

    These files were generated by Greg McFarquhar and Robert Jackson at the University of Illinois. Please contact mcfarq@atmos.uiuc.edu or rjackso2@atmos.uiuc.edu for more information or for assistance in interpreting the content of these files. We highly recommend that anyone wishing to use these files do so in a collaborative endeavor and we welcome queries and opportunities for collaboration. There are caveats associated with the use of the data which are difficult to thoroughly document and not all products for all time periods have been thoroughly examined. This is a value added data set of the best estimate of cloud microphysical parameters derived using data collected by the cloud microphysical probes installed on the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter during RACORO. These files contain best estimates of liquid size distributions N(D) in terms of droplet diameter D, liquid water content LWC, extinction of liquid drops beta, effective radius of cloud drops (re), total number concentration of droplets NT, and radar reflectivity factor Z at 1 second resolution.

  6. ARM - PI Product - ISDAC Microphysics

    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 Microphysics ARM Data Discovery Browse

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

    E-Print Network [OSTI]

    Stuart, Amy L.

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

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

    E-Print Network [OSTI]

    Gettelman, Andrew

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

  9. Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals

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

    Shupe, Matthew

    Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May 2008). These time periods will be expanded in a future submission.

  10. Simulating mixed-phase Arctic stratus clouds: Sensitivity to ice initiation mechanisms

    E-Print Network [OSTI]

    Sednev, I.

    2009-01-01T23:59:59.000Z

    parameterization in BRM scheme accounts for two general mech- anisms distinguishable according to the involvement of liquid phase in the ice

  11. Studying Mixed-Phased Clouds Using Ground-Based Active and Passive Remote Sensors

    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 InstagramStructure of All-Polymer. . ~0s ALAMOS SCIENTIFICStudyingStudying

  12. Radiative Influences on Glaciation Time-Scales of Mixed-Phase 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's PossibleRadiation Protection Radiation Protection Regulations: The FederalRadiativeRadiative

  13. Effects of aerosols on deep convective cumulus clouds

    E-Print Network [OSTI]

    Fan, Jiwen

    2009-05-15T23:59:59.000Z

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

  14. Cirrus Microphysical Properties from Stellar Aureole Measurements, Phase I

    SciTech Connect (OSTI)

    DeVore, J.G.; Kristl, J.A.; Rappaport, S.A

    2012-04-20T23:59:59.000Z

    While knowledge of the impact of aerosols on climate change has improved significantly due to the routine, ground-based, sun photometer measurements of aerosols made at AERONET sites world-wide, the impact of cirrus clouds remains much less certain because they occur high in the atmosphere and are more difficult to measure. This report documents work performed on a Phase I SBIR project to retrieve microphysical properties of cirrus ice crystals from stellar aureole imagery. The Phase I work demonstrates that (1) we have clearly measured stellar aureole profiles; (2) we can follow the aureole profiles out to ~1/4 degree from stars (~1/2 degree from Jupiter); (3) the stellar aureoles from cirrus have very distinctive profiles, being flat out to a critical angle, followed by a steep power-law decline with a slope of ~-3; (4) the profiles are well modeled using exponential size distributions; and (5) the critical angle in the profiles is ~0.12 degrees, (6) indicating that the corresponding critical size ranges from ~150 to ~200 microns. The stage has been set for a Phase II project (1) to proceed to validating the use of stellar aureole measurements for retrieving cirrus particle size distributions using comparisons with optical property retrievals from other, ground-based instruments and (2) to develop an instrument for the routine, automatic measurement of thin cirrus microphysical properties.

  15. Cloud a particle beam facility to investigate the influence of cosmic rays on clouds

    E-Print Network [OSTI]

    Kirkby, Jasper

    2001-01-01T23:59:59.000Z

    Palaeoclimatic data provide extensive evidence for solar forcing of the climate during the Holocene and the last ice age, but the underlying mechanism remains a mystery. However recent observations suggest that cosmic rays may play a key role. Satellite data have revealed a surprising correlation between cosmic ray intensity and the fraction of the Earth covered by low clouds \\cite{svensmark97,marsh}. Since the cosmic ray intensity is modulated by the solar wind, this may be an important clue to the long-sought mechanism for solar-climate variability. In order to test whether cosmic rays and clouds are causally linked and, if so, to understand the microphysical mechanisms, a novel experiment known as CLOUD\\footnotemark\\ has been proposed \\cite{cloud_proposal}--\\cite{cloud_addendum_2}. CLOUD proposes to investigate ion-aerosol-cloud microphysics under controlled laboratory conditions using a beam from a particle accelerator, which provides a precisely adjustable and measurable artificial source of cosmic rays....

  16. DRAFT, last update 5 January 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and

    E-Print Network [OSTI]

    Wood, Robert

    phase and ice processes. Respectively, the parameterization of these processes for GCMs is further away and aerosol parameterizations, but intense research efforts aimed at improving the realism of cloud lower than for the shallow clouds, as the deep clouds are much more complicated, because mixed phase

  17. Mixed-phase clouds, thin cirrus clouds, and OLR over the tropics: observations, retrievals, and radiative impacts 

    E-Print Network [OSTI]

    Lee, Joonsuk

    2009-06-02T23:59:59.000Z

    The tropics is a very important region in terms of earth’s radiation budget because the net radiative heating is largest in the tropics and that surplus energy is redistributed by the circulations of oceans and atmospheres. Moreover, a large number...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. On the microphysics of a hail-bearing cloud

    E-Print Network [OSTI]

    Smith, David Ray

    1973-01-01T23:59:59.000Z

    eq uation & (4. 1) 2 Since w ? "- bg, , quation (4. 1) i put into the finite- dz dz difference form; b. = -b. + j j for computational purposes. ni2 w. (4. 2) The snbcloud region is characterized by dry adiabatic cordi- ti ns so...

  3. ARM - PI Product - Atmospheric State, Cloud Microphysics & Radiative Flux

    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 : XDCnarrowbandheat fluxChinaNews :ProductsAerosol Retrievals from

  4. The Sensitivity of Radiative Fluxes to Parameterized Cloud Microphysics

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

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

  5. Impact of cloud microphysics on squall line organization

    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 School footballHydrogenIT |HotImpact of GeneratorImpact ofARM

  6. Sensitivity of Radiative Fluxes and Heating Rates to Cloud Microphysics

    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

  7. Fidelity of Analytic Drop Size Distributions in Drizzling Stratiform Clouds Based on Large-Eddy Simulations

    E-Print Network [OSTI]

    Kogan, Yefim L.; Kogan, Zena N.; Mechem, David B.

    2009-08-01T23:59:59.000Z

    Cloud microphysical parameterizations and retrievals rely heavily on knowledge of the shape of drop size distributions (DSDs). Many investigations assume that DSDs in the entire or partial drop size range may be approximated ...

  8. Aerosolcloudprecipitation interactions. Part 1. The nature and sources of cloud-active aerosols

    E-Print Network [OSTI]

    Rutledge, Steven

    Aerosol­cloud­precipitation interactions. Part 1. The nature and sources of cloud-active aerosols M Available online 13 March 2008 Keywords: aerosol precipitation CCN emissions clouds Atmospheric aerosol the chemical composition of aerosols, their microphysical properties, and the factors that enable them to act

  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. 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.

  11. Unraveling the origins of electromechanical response in mixed-phase Bismuth Ferrite

    SciTech Connect (OSTI)

    Vasudevan, Rama K [ORNL; Okatan, M. B. [University of New South Wales; Liu, Y. Y. [University of Washington, Seattle; Jesse, Stephen [ORNL; Yang, J.-C. [University of California, Berkeley; Liang, W. -I. [National Chiao Tung University, Hsinchu, Taiwan; Chu, Ying-Hao [National Chiao Tung University, Hsinchu, Taiwan; Li, J. Y. [University of Washington, Seattle; Kalinin, Sergei V [ORNL; Valanoor, Nagarajan V [ORNL

    2013-01-01T23:59:59.000Z

    The origin of giant electromechanical response in a mixed-phase rhombohedral-tetragonal BiFeO3 thin film is probed using sub-coercive scanning probe microscopy based multiple-harmonic measurements. Significant contributions to the strain arise from a second-order harmonic response localized at the phase boundaries. Strain and dissipation data, backed by thermodynamic calculations suggest that the source of the enhanced electromechanical response is the motion of phase boundaries. These findings elucidate the key role of labile phase boundaries, both natural and artificial, in achieving thin films with giant electromechanical properties.

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

    E-Print Network [OSTI]

    Hogan, Robin

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

  13. Z .Atmospheric Research 57 2001 5180 www.elsevier.comrlocateratmos

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    2 , depending on the ice habit. It is also shown that mixed-phase clouds are more sensitive; Radiation budget; Ice optical properties; Mixed phase ) Corresponding author. Tel.: q1-814-863-1584; fax: q1 for the parameterization of cloud optical properties in bulk and bin microphysical models. Implications for arctic cloudy

  14. Thermodynamically Anomalous Regions and Possible New Signals of Mixed Phase Formation

    E-Print Network [OSTI]

    K. A. Bugaev; A. I. Ivanytskyi; D. R. Oliinychenko; V. V. Sagun; I. N. Mishustin; D. H. Rischke; L. M. Satarov; G. M. Zinovjev

    2014-12-01T23:59:59.000Z

    Using an advanced version of the hadron resonance gas model we have found remarkable irregularities of relativistic heavy-ion collisions at chemical freeze-out. They include an abrupt change of the effective number of degrees of freedom at laboratory energies 8.9-11.6 AGeV and plateaus in the collision-energy dependence of the entropy per baryon, total pion number per baryon, and thermal pion number per baryon at laboratory energies 6.9-11.6 AGeV. Also at chemical freeze-out we observe a sharp peak in the dimensionless trace anomaly at laboratory energy 11.6 AGeV. On the basis of the generalized shock-adiabat model we demonstrate that these observations give evidence for the anomalous thermodynamic properties of the mixed phase at its boundary to the quark-gluon plasma. We argue that the trace anomaly peak and the local minimum of the generalized specific volume observed at a laboratory energy of 11.6 AGeV provide a signal for the formation of a mixed phase between the quark-gluon plasma and the hadron phase.

  15. High Cloud Properties from Three Years of MODIS Terra and Aqua Collection-4 Data over the Tropics

    E-Print Network [OSTI]

    Baum, Bryan A.

    High Cloud Properties from Three Years of MODIS Terra and Aqua Collection-4 Data over the Tropics) ABSTRACT This study surveys the optical and microphysical properties of high (ice) clouds over the Tropics on the gridded level-3 cloud products derived from the measurements acquired by the Moderate Resolution Imaging

  16. Evaluation of the aerosol indirect effect in marine stratocumulus clouds: Droplet number, size, liquid water path, and radiative impact

    E-Print Network [OSTI]

    Russell, Lynn

    Evaluation of the aerosol indirect effect in marine stratocumulus clouds: Droplet number, size stratocumulus clouds in the northeastern Pacific Ocean were analyzed to determine the effect of aerosol particles on cloud microphysical and radiative properties. Seven nighttime and two daytime cases were

  17. DISSERTATION THE EFFECTS OF RADIATIVE AND MICROPHYSICAL PROCESSES ON

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    model is coupled in a consistent fashion to the bulk microphysical parameterization of Walko et al. (1995), an explicit liquid bin microphysical model (e.g. Feingold et al. 1996a) and a mixed­phase that boundary layer stability is strongly dependent upon ice processes, illustrating that the rapid reduction

  18. Absence of Thermophoretic Flow in Relativistic Heavy-Ion Collisions as an Indicator for the Absence of a Mixed Phase

    E-Print Network [OSTI]

    Markus H. Thoma

    2002-04-30T23:59:59.000Z

    If a quark-gluon plasma is formed in relativistic heavy-ion collisions, there may or may not be a mixed phase of quarks, gluons and hadronic clusters when the critical temperature is reached in the expansion of the fireball. If there is a temperature gradient in the fireball, the hadronic clusters, embedded in the heat bath of quarks and gluons, are subjected to a thermophoretic force. It is shown that even for small temperature gradients and short lifetimes of the mixed phase, thermophoresis would lead to a flow essentially stronger than the observed one. The absence of this strong flow provides support for a rapid or sudden hadronization mechanism without a mixed phase.

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

    SciTech Connect (OSTI)

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

    2014-03-27T23:59:59.000Z

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

  20. Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases

    E-Print Network [OSTI]

    McGehee, Michael

    Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases Sean Sweetnam, Kenneth R. Graham,, Guy O. Ngongang Ndjawa, Thomas Heumuller offsets between the charge transport energy levels in different morphological phases of polymer

  1. High-performance solar-blind ultraviolet photodetector based on mixed-phase ZnMgO thin film

    SciTech Connect (OSTI)

    Fan, M. M. [Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, 130033 Changchun (China); Liu, K. W., E-mail: liukw@ciomp.ac.cn, E-mail: shendz@ciomp.ac.cn; Zhang, Z. Z.; Li, B. H.; Chen, X.; Zhao, D. X.; Shan, C. X.; Shen, D. Z., E-mail: liukw@ciomp.ac.cn, E-mail: shendz@ciomp.ac.cn [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, 130033 Changchun (China)

    2014-07-07T23:59:59.000Z

    High Mg content mixed-phase Zn{sub 0.38}Mg{sub 0.62}O was deposited on a-face sapphire by plasma-assisted molecular beam epitaxy, based on which a metal-semiconductor-metal solar-blind ultraviolet (UV) photodetector was fabricated. The dark current is only 0.25?pA at 5?V, which is much lower than that of the reported mixed-phase ZnMgO photodetectors. More interestingly, different from the other mixed-phase ZnMgO photodetectors containing two photoresponse bands, this device shows only one response peak and its ?3?dB cut-off wavelength is around 275?nm. At 10?V, the peak responsivity is as high as 1.664?A/W at 260?nm, corresponding to an internal gain of ?8. The internal gain is mainly ascribed to the interface states at the grain boundaries acting as trapping centers of photogenerated holes. In view of the advantages of mixed-phase ZnMgO photodetectors over single-phase ZnMgO photodetectors, including easy fabrication, high responsivity, and low dark current, our findings are anticipated to pave a new way for the development of ZnMgO solar-blind UV photodetectors.

  2. Ice nucleation and overseeding of ice in volcanic clouds A. J. Durant,1,2

    E-Print Network [OSTI]

    Rose, William I.

    that such ``overseeded'' volcanic clouds will exhibit enhanced ice crystal concentrations and smaller average ice crystal nucleation in volcanic plumes and clouds affects dynamics [Glaze et al., 1997; Herzog et al., 1998; Mastin- porting water to the stratosphere [Glaze et al., 1997] and these fluxes depend in part on the microphysics

  3. Environmental control of cloud-to-ground lightning polarity in severe storms

    E-Print Network [OSTI]

    Buffalo, Kurt Matthew

    2008-10-10T23:59:59.000Z

    polarity of severe storms by directly affecting their structural, dynamical, and microphysical properties, which in turn directly control cloud electrification and CG flash polarity. A more specific hypothesis, which has been supported by past............................................................................... 23 a. Thunderstorm electrification ................................................ 23 1) Charging mechanisms and typical charge structure ... 23 2) Cloud-to-ground lightning flash................................. 27 3...

  4. The Ability of MM5 to Simulate Ice Clouds: Systematic Comparison between Simulated and Measured Fluxes and Lidar/Radar Profiles at the

    E-Print Network [OSTI]

    Protat, Alain

    distribution are critical to the global radiative effect of ice clouds. One of the main uncertainties. To quantify the effect of these clouds onto climate and weather systems, their global coverage, altitude, tem effect. Both macrophysical and microphysical properties of ice clouds regulate this equilibrium

  5. Mapping strain modulated electronic structure perturbations in mixed phase bismuth ferrite thin films

    SciTech Connect (OSTI)

    Krishnan, P.S. Sanakara R.; Aguiar, Jeffery A.; Ramasse, Q. M.; Kepaptsoglou, D. M.; Liang, W. I.; Chu, Y. H.; Browning, Nigel D.; Munroe, Paul R.; Nagarajan, Valanoor

    2015-01-01T23:59:59.000Z

    Strain engineering of epitaxial ferroelectrics has emerged as a powerful method to tailor the electromechanical response of these materials, although the effect of strain at the atomic scale and the interplay between lattice displacements and electronic structure changes are not yet fully understood. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we systematically probe the role of epitaxial strain in mixed phase bismuth ferrite thin films. Electron energy loss O K and Fe L2,3 edge spectra acquired across the rhombohedral (R)-tetragonal (T) phase boundary reveal progressive, and systematic changes, in electronic structure going from one phase to the other. The comparison of the acquired spectra, with theoretical simulations using DFT, suggests a breakage in the structural symmetry across the boundary due to the simultaneous presence of increasing epitaxial strain and off- axial symmetry in the T phase. This implies that the imposed epitaxial strain plays a significant role in not only changing the crystal-field geometry, but also the bonding environment surrounding the central iron cation at the interface thus providing new insights and a possible link to understand how the imposed strain could perturb magnetic ordering in the T phase BFO.

  6. Microphysical/mesoscale aspects of nuclear winter and new directions in assessments

    SciTech Connect (OSTI)

    Knox, J.B.

    1985-06-01T23:59:59.000Z

    Recent results of model studies and sensitivity tests have shown the degree to which the intensity and duration of ''nuclear winter'' depends on the mass of soot and dust suspended, its optical properties, its vertical distribution in the atmosphere, and the residence time. The soot from urban fires is viewed as evolving during its dispersion from the early fire induced plumes, to cloud scale systems, to the mesoscale and larger systems. Micro-physical processes are perceived as operating within these systems in a manner to enhance removal from the troposphere, and to alter the verical distribution of the soot or its subsequent, aging or evolving aerosol. Relevant observations and studies of these processes are presented and discussed. Critical inputs to the climate simulation models may well be altered significantly by these process effects, many of which are in need of better definition. Appropriate research needs to be initiated to address and better define these microphysical/mesoscale processes of potential importance in the altered atmospheric system after a major nuclear exchange. 11 refs., 2 figs.

  7. Tropical Cloud Properties and Radiative Heating Profiles

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

    Mather, James

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

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

    SciTech Connect (OSTI)

    Lee, In Young

    1993-09-01T23:59:59.000Z

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

  9. The Diurnal Cycle of Clouds and Precipitation along the Sierra Madre Occidental Observed during NAME-2004: Implications for Warm Season Precipitation Estimation

    E-Print Network [OSTI]

    Rutledge, Steven

    . Ground-based precipitation retrievals from the NAME Event Rain Gauge Network (NERN) and Colorado State University­National Center for Atmospheric Research (CSU­NCAR) version 2 radar composites over the southern due to changes in the depth and vigor of shallow clouds and mixed-phase cloud depths

  10. Microphysical effects determine macrophysical response for aerosol impacts on deep

    E-Print Network [OSTI]

    Li, Zhanqing

    cloud cover, cloud top height, and radiative forcing. We found that although the widely accepted theory. The thermodynamic invigoration effect contrib- utes up to 27% of total increase in cloud cover. The overall aerosol by aerosols that drives the dramatic increase in cloud cover, cloud top height, and cloud thickness

  11. Investigation of the photoactivity of pristine and mixed phase N-doped titania under visible and solar irradiation

    SciTech Connect (OSTI)

    Das, Barnali [Solar and Energy Materials Laboratory, Department of Energy, Tezpur University, Tezpur, Assam 784028 (India); Nair, Ranjith G. [Solar and Energy Materials Laboratory, Department of Energy, Tezpur University, Tezpur, Assam 784028 (India); Department of Physics, National Institute of Technology-Silchar, Silchar, Assam 788010 (India); Rajbongshi, Bijumani [Solar and Energy Materials Laboratory, Department of Energy, Tezpur University, Tezpur, Assam 784028 (India); Samdarshi, S.K., E-mail: drsksamdarshi@rediffmail.com [Solar and Energy Materials Laboratory, Department of Energy, Tezpur University, Tezpur, Assam 784028 (India)

    2013-09-15T23:59:59.000Z

    Nitrogen doped titania nano-particles were synthesized by sol–gel method with an aim to investigate the impact of doping in titanium matrix and the titania phases on their photocatalytic activity under visible and solar irradiation. The structural, optical and chemical characterization of the prepared materials were done using X-ray diffraction analysis, scanning electron microscopy, UV–visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, and Fourier transform infrared spectroscopy. The samples were calcined at different temperatures (200 °C–600 °C) to obtain different phases. All the samples showed red-shift in the visible region attributable to the doping of nitrogen in the titania matrix. The samples calcined at low temperatures showed high photocatalytic activity compared to the high temperature samples. The enhancement in the visible light activity may be attributed to the large amount of nitrogen present in the surface region of the catalyst and reduced carrier recombination. Among the high temperature samples the high activity may be due to the presence of mixed phase as well. - Highlights: • Pristine and mixed phases of N doped titania synthesized at different temperatures. • High visible light photoactivity exhibited by pristine rutile phase and mixed phase. • Role of surface N in rutile and matrix embedded N in other samples corroborated.

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

    E-Print Network [OSTI]

    Sillman, Sanford

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

  13. Effects of Ocean Ecosystem on Marine Aerosol-Cloud Interaction

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

    Meskhidze, Nicholas; Nenes, Athanasios

    2010-01-01T23:59:59.000Z

    Using satellite data for the surface ocean, aerosol optical depth (AOD), and cloud microphysical parameters, we show that statistically significant positive correlations exist between ocean ecosystem productivity, the abundance of submicron aerosols, and cloud microphysical properties over different parts of the remote oceans. The correlation coefficient for remotely sensed surface chlorophyllaconcentration ([Chl-a]) and liquid cloud effective radii over productive areas of the oceans varies between?0.2and?0.6. Special attention is given to identifying (and addressing) problems from correlation analysis used in the previous studies that can lead to erroneous conclusions. A new approach (using the difference between retrieved AOD and predicted seamore »salt aerosol optical depth,AODdiff) is developed to explore causal links between ocean physical and biological systems and the abundance of cloud condensation nuclei (CCN) in the remote marine atmosphere. We have found that over multiple time periods, 550?nmAODdiff(sensitive to accumulation mode aerosol, which is the prime contributor to CCN) correlates well with [Chl-a] over the productive waters of the Southern Ocean. Since [Chl-a] can be used as a proxy of ocean biological productivity, our analysis demonstrates the role of ocean ecology in contributing CCN, thus shaping the microphysical properties of low-level marine clouds.« less

  14. Adaptive low Mach number simulations of nuclear flame microphysics

    E-Print Network [OSTI]

    Bell, John B.

    Adaptive low Mach number simulations of nuclear flame microphysics J. B. Bell, M. S. Day, C. A of nuclear flames in Type Ia su- pernovae. This model is based on a low Mach number formulation nuclear burning. The formulation presented here generalizes low Mach number models used in combustion

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

    E-Print Network [OSTI]

    Vogel, Jonathan 1988-

    2012-08-21T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Vogel, Jonathan 1988-

    2012-08-21T23:59:59.000Z

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

  17. Climate implications of carbonaceous aerosols: An aerosol microphysical study using the GISS/MATRIX climate model

    E-Print Network [OSTI]

    Bauer, Susanne E.

    2010-01-01T23:59:59.000Z

    and R. Ruedy, Matrix (multiconfiguration aerosol tracker ofmixing state): An aerosol microphysical module for globalAn investigative review, Aerosol Sci. Technol. , Vol. 40,

  18. The Separate Physics and Dynamics Experiment (SPADE) framework for determining resolution awareness: A case study of microphysics

    SciTech Connect (OSTI)

    Gustafson, William I.; Ma, Po-Lun; Xiao, Heng; Singh, Balwinder; Rasch, Philip J.; Fast, Jerome D.

    2013-08-29T23:59:59.000Z

    The ability to use multi-resolution dynamical cores for weather and climate modeling is pushing the atmospheric community towards developing scale aware or, more specifically, resolution aware parameterizations that will function properly across a range of grid spacings. Determining the resolution dependence of specific model parameterizations is difficult due to strong resolution dependencies in many pieces of the model. This study presents the Separate Physics and Dynamics Experiment (SPADE) framework that can be used to isolate the resolution dependent behavior of specific parameterizations without conflating resolution dependencies from other portions of the model. To demonstrate the SPADE framework, the resolution dependence of the Morrison microphysics from the Weather Research and Forecasting model and the Morrison-Gettelman microphysics from the Community Atmosphere Model are compared for grid spacings spanning the cloud modeling gray zone. It is shown that the Morrison scheme has stronger resolution dependence than Morrison-Gettelman, and that the ability of Morrison-Gettelman to use partial cloud fractions is not the primary reason for this difference. This study also discusses how to frame the issue of resolution dependence, the meaning of which has often been assumed, but not clearly expressed in the atmospheric modeling community. It is proposed that parameterization resolution dependence can be expressed in terms of "resolution dependence of the first type," RA1, which implies that the parameterization behavior converges towards observations with increasing resolution, or as "resolution dependence of the second type," RA2, which requires that the parameterization reproduces the same behavior across a range of grid spacings when compared at a given coarser resolution. RA2 behavior is considered the ideal, but brings with it serious implications due to limitations of parameterizations to accurately estimate reality with coarse grid spacing. The type of resolution awareness developers should target in their development depends upon the particular modeler’s application.

  19. ARM - Field Campaign - Rain Microphysics Study with Disdrometer and

    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- Polarization DiversityPolarization Radar govCampaignsRain Microphysics Study with

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

    SciTech Connect (OSTI)

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

    2013-05-25T23:59:59.000Z

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

  1. 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.

  2. A forward microphysical model to predict the size-distribution parameters of laboratory generated (mimic)

    E-Print Network [OSTI]

    Oxford, University of

    A forward microphysical model to predict the size- distribution parameters of laboratory generated Interactions ­ Condensational Growth and Coagulation, Submitted for Indian Aerosol Science and Technology Microphysical Model for the UTLS (FAMMUS) is applied to predict the size-distribution parameters of laboratory

  3. 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.

  4. aerosol microphysical characteristics: Topics by E-print Network

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

    in radiative flux calculations Engineering Websites Summary: the regional and global climate through its indirect effects by serving as cloud condensation nuclei 4 retrieving...

  5. 9.7 Studies of Arctic Mixed-Phase Clouds from SHEBA/FIRE/ACE: May 1-10 Case Study , J. Intrieri

    E-Print Network [OSTI]

    Zuidema, Paquita

    the measured surface infrared flux, especially during the winter months (Intrieri and Shupe, 2002). Other to characterize. Measurements from surface-based remote sensors hold the promise of com- prehensive documentation measurements encourage confidence in the surface sen- sor evaluation. 2. Data and Method 2.1 Data Table 1 and 2

  6. Intercomparison and Evaluation of Global Aerosol Microphysical Properties among AeroCom Models of a Range of Complexity

    SciTech Connect (OSTI)

    Mann, G. W.; Carslaw, K. S.; Reddington, C. L.; Pringle, K. J.; Schulz, M.; Asmi, A.; Spracklen, D. V.; Ridley, D. A.; Woodhouse, M. T.; Lee, L. A.; Zhang, Kai; Ghan, Steven J.; Easter, Richard C.; Liu, Xiaohong; Stier, P.; Lee, Y. H.; Adams, P. J.; Tost, H.; Lelieveld, J.; Bauer, S.; Tsigaridis, Kostas; van Noije, T.; Strunk, A.; Vignati, E.; Bellouin, N.; Dalvi, M.; Johnson, C. E.; Bergman, T.; Kokkola, H.; Von Salzen, Knut; Yu, Fangqun; Luo, Gan; Petzold, A.; Heintzenberg, J.; Clarke, A. D.; Ogren, J. A.; Gras, J.; Baltensperger, Urs; Kaminski, U.; Jennings, S. G.; O'Dowd, C. D.; Harrison, R. M.; Beddows, D. C.; Kulmala, M.; Viisanen, Y.; Ulevicius, V.; Mihalopoulos, Nikos; Zdimal, V.; Fiebig, M.; Hansson, H. C.; Swietlicki, E.; Henzing, J. S.

    2014-05-13T23:59:59.000Z

    Many of the next generation of global climate models will include aerosol schemes which explicitly simulate the microphysical processes that determine the particle size distribution. These models enable aerosol optical properties and cloud condensation nuclei (CCN) concentrations to be determined by fundamental aerosol processes, which should lead to a more physically based simulation of aerosol direct and indirect radiative forcings. This study examines the global variation in particle size distribution simulated by twelve global aerosol microphysics models to quantify model diversity and to identify any common biases against observations. Evaluation against size distribution measurements from a new European network of aerosol supersites shows that the mean model agrees quite well with the observations at many sites on the annual mean, but there are some seasonal biases common to many sites. In particular, at many of these European sites, the accumulation mode number concentration is biased low during winter and Aitken mode concentrations tend to be overestimated in winter and underestimated in summer. At high northern latitudes, the models strongly underpredict Aitken and accumulation particle concentrations compared to the measurements, consistent with previous studies that have highlighted the poor performance of global aerosol models in the Arctic. In the marine boundary layer, the models capture the observed meridional variation in the size distribution, which is dominated by the Aitken mode at high latitudes, with an increasing concentration of accumulation particles with decreasing latitude. Considering vertical profiles, the models reproduce the observed peak in total particle concentrations in the upper troposphere due to new particle formation, although modelled peak concentrations tend to be biased high over Europe. Overall, the results suggest that most global aerosol microphysics models simulate the global variation of the particle size distribution with a good degree of skill, but some models are in poor agreement with the observations. Further work is required to better constrain size-resolved primary and secondary particle number sources, and an improved understanding of nucleation and growth (e.g. the role of nitrate and secondary organics) will improve the fidelity of simulated particle size distributions.

  7. Sensitivity of the Mueller matrix to the optical and microphysical properties of cirrus clouds

    E-Print Network [OSTI]

    Lawless, Ryan Lee

    2006-10-30T23:59:59.000Z

    by considering four different incident polarization states. The sensitivity of these elements is observed by comparing different ice crystal habits, effective sizes, and optical depth. The Mueller elements are strongly dependent on habit. The three habits...

  8. Posters A One-Dimensional Radiative Convective Model with Detailed Cloud Microphysics

    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 observations71 Posters A5

  9. Use of In Situ Observations to Characterize Cloud Microphysical and Radiative Properties: Application to Climate Studies

    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 SpinPrinceton PlasmaAfternoon4. Uranium purchasedUrbanHerbivores -Use of

  10. Modification and Application of a New Method for Retrieving Water-Cloud Microphysics Vertical Profile

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

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

  11. Overview of the COPS Aerosol and Cloud Microphysics (ACM) Subgroup Activities

    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 for RenewableSpeedingBiomass and BiofuelsOversight Board TheOverview of the ARM/FIRECOPS

  12. Cloud Effects on Radiative Heating Rate Profiles over Darwin using ARM and A-train Radar/Lidar Observations

    SciTech Connect (OSTI)

    Thorsen, Tyler J.; Fu, Qiang; Comstock, Jennifer M.

    2013-06-11T23:59:59.000Z

    Observations of clouds from the ground-based U.S. Department of Energy Atmospheric Radiation Measurement program (ARM) and satellite-based A-train are used to compute cloud radiative forcing profiles over the ARM Darwin, Australia site. Cloud properties are obtained from both radar (the ARM Millimeter Cloud Radar (MMCR) and the CloudSat satellite in the A-train) and lidar (the ARM Micropulse lidar (MPL) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite in the A-train) observations. Cloud microphysical properties are taken from combined radar and lidar retrievals for ice clouds and radar only or lidar only retrievals for liquid clouds. Large, statistically significant differences of up to 1.43 K/day exist between the mean ARM and A-train net cloud radiative forcing profiles. The majority of the difference in cloud radiative forcing profiles is shown to be due to a large difference in the cloud fraction above 12 km. Above this altitude the A-train cloud fraction is significantly larger because more clouds are detected by CALIPSO than by the ground-based MPL. It is shown that the MPL is unable to observe as many high clouds as CALIPSO due to being more frequently attenuated and a poorer sensitivity even in otherwise clear-sky conditions. After accounting for cloud fraction differences and instrument sampling differences due to viewing platform we determined that differences in cloud radiative forcing due to the retrieved ice cloud properties is relatively small. This study demonstrates that A-train observations are better suited for the calculation cloud radiative forcing profiles. In addition, we find that it is necessary to supplement CloudSat with CALIPSO observations to obtain accurate cloud radiative forcing profiles since a large portion of clouds at Darwin are detected by CALIPSO only.

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

    SciTech Connect (OSTI)

    Lohmann,U.; Schwartz, S. E.

    2008-03-02T23:59:59.000Z

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

  14. AEROSOL, CLOUDS, AND CLIMATE CHANGE

    SciTech Connect (OSTI)

    SCHWARTZ, S.E.

    2005-09-01T23:59:59.000Z

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

  15. ATMOSPHERIC ELSEVIER AtmosphericResearch 38 (1995) 2942

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    parameterization Part I: the single-moment scheme R.L. Walko, W.R. Cotton *, M.P. Meyers, J.Y. Harrington Colorado 1994 Abstract A new cloud microphysical parameterization is described. Features of this new scheme; the use of a heat budget equation for hydrometeor classes, allowing heat storage and mixed phase hydrome

  16. Atmos. Chem. Phys., 14, 1041110430, 2014 www.atmos-chem-phys.net/14/10411/2014/

    E-Print Network [OSTI]

    Pierce, Jeffrey

    -nucleation-theory-based parameterization of heterogeneous ice nucleation (Hoose et al., 2010) in the Community Atmospheric Model version 5 nucleation than that of soot in mixed-phase clouds. The new parameterizations implemented in CAM5 induce more significant aerosol indirect effects than the de- fault parameterization. 1 Introduction Ice microphysical

  17. Nondegenerate parametric generation of 2.2-mJ, few-cycle 2.05-?m pulses using a mixed phase matching scheme

    SciTech Connect (OSTI)

    Xu, Guibao; Wandel, Scott F.; Jovanovic, Igor, E-mail: ijovanovic@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-02-15T23:59:59.000Z

    We describe the production of 2.2-mJ, ?6 optical-cycle-long mid-infrared laser pulses with a carrier wavelength of 2.05 ?m in a two-stage ?-BaB{sub 2}O{sub 4} nondegenerate optical parametric amplifier design with a mixed phase matching scheme, which is pumped by a standard Ti:sapphire chirped-pulse amplification system. It is demonstrated that relatively high pulse energies, short pulse durations, high stability, and excellent beam profiles can be obtained using this simple approach, even without the use of optical parametric chirped-pulse amplification.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. On the microphysical foundations of rate-and-state friction Thibaut Putelat,a,c

    E-Print Network [OSTI]

    Dawes, Jon

    -and-state formulation of dry friction is well established as a phenomenological yet quantitative description of dry in the evolution of frictional stick-slip processes. This overturned the classical idea of Coulomb frictionOn the microphysical foundations of rate-and-state friction Thibaut Putelat,a,c , Jonathan H. P

  7. Cloud Computing og availability

    E-Print Network [OSTI]

    Christensen, Henrik Bćrbak

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

  8. 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 ...

  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. Study of particulate matter formation and evolution in near-field aircraft plumes using a one-dimensional microphysical model

    E-Print Network [OSTI]

    Zhang, Jianye, S.M. Massachusetts Institute of Technology

    2007-01-01T23:59:59.000Z

    Environmental concerns have led to a growing effort to investigate and characterize the particulate matter (PM) emissions from aircraft engines. This thesis presents a one-dimensional microphysics and chemical kinetics ...

  11. 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

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

    SciTech Connect (OSTI)

    None

    2013-10-18T23:59:59.000Z

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

  13. Aerosol Impacts on California Winter Clouds and Precipitation during CalWater 2011: Local Pollution versus Long-Range Transported Dust

    SciTech Connect (OSTI)

    Fan, Jiwen; Leung, Lai-Yung R.; DeMott, Paul J.; Comstock, Jennifer M.; Singh, Balwinder; Rosenfeld, Daniel; Tomlinson, Jason M.; White, Allen B.; Prather, Kimberly; Minnis, Patrick; Ayers, J. K.; Min, Qilong

    2014-01-03T23:59:59.000Z

    Mineral dust aerosols often observed over California in winter and spring, associated with long-range transport from Asia and Sahara, have been linked to enhanced precipitation based on observations. Local anthropogenic pollution, on the other hand, was shown in previous observational and modeling studies to reduce precipitation. Here we incorporate recent developments in ice nucleation parameterizations to link aerosols with ice crystal formation in a spectral-bin cloud microphysical model coupled with the Weather Research and Forecasting (WRF) model, to examine the relative and combined impacts of dust and local pollution particles on cloud properties and precipitation type and intensity. Simulations are carried out for two cloud cases with contrasting meteorology and cloud dynamics that occurred on February 16 (FEB16) and March 02 (MAR02) from the CalWater 2011 field campaign. In both cases, observations show the presence of dust and biological particles in a relative pristine environment. The simulated cloud microphysical properties and precipitation show reasonable agreement with aircraft and surface measurements. Model sensitivity experiments indicate that in the pristine environment, the dust and biological aerosol layers increase the accumulated precipitation by 10-20% from the Central Valley to the Sierra Nevada Mountains for both FEB16 and MAR02 due to a ~40% increase in snow formation, validating the observational hypothesis. Model results show that local pollution increases precipitation over the windward slope of the mountains by few percent due to increased snow formation when dust is present but reduces precipitation by 5-8% if dust is removed on FEB16. The effects of local pollution on cloud microphysics and precipitation strongly depend on meteorology including the strength of the Sierra Barrier Jet, and cloud dynamics. This study further underscores the importance of the interactions between local pollution, dust, and environmental conditions for assessing aerosol effects on cold season precipitation in California.

  14. ARM - PI Product - In-Situ Microphysics from the MPACE 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 for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDAC Microphysics ARM Data Discovery

  15. ARM - PI Product - In-Situ Microphysics from the RACORO 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 for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDCnarrowbandheatProductsISDAC Microphysics ARM Data

  16. 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

  17. Comparison of Simulated and Observed Continental Tropical Anvil Clouds and Their Radiative Heating Profiles

    SciTech Connect (OSTI)

    Powell, Scott W.; Houze, R.; Kumar, Anil; McFarlane, Sally A.

    2012-09-06T23:59:59.000Z

    Vertically pointing millimeter-wavelength radar observations of anvil clouds extending from mesoscale convective systems (MCSs) that pass over an Atmospheric Radiation Measurement Program (ARM) field site in Niamey, Niger, are compared to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model using six different microphysical schemes. The radar data provide the statistical distribution of the radar reflectivity values as a function of height and anvil thickness. These statistics are compared to the statistics of the modeled anvil cloud reflectivity at all altitudes. Requiring the model to be statistically accurate at all altitudes is a stringent test of the model performance. The typical vertical profile of radiative heating in the anvil clouds is computed from the radar observations. Variability of anvil structures from the different microphysical schemes provides an estimate of the inherent uncertainty in anvil radiative heating profiles. All schemes underestimate the optical thickness of thin anvils and cirrus, resulting in a bias of excessive net anvil heating in all of the simulations.

  18. A New WRF-Chem Treatment for Studying Regional Scale Impacts of Cloud-Aerosol Interactions in Parameterized Cumuli

    SciTech Connect (OSTI)

    Berg, Larry K.; Shrivastava, ManishKumar B.; Easter, Richard C.; Fast, Jerome D.; Chapman, Elaine G.; Liu, Ying

    2015-01-01T23:59:59.000Z

    A new treatment of cloud-aerosol interactions within parameterized shallow and deep convection has been implemented in WRF-Chem that can be used to better understand the aerosol lifecycle over regional to synoptic scales. The modifications to the model to represent cloud-aerosol interactions include treatment of the cloud dropletnumber mixing ratio; key cloud microphysical and macrophysical parameters (including the updraft fractional area, updraft and downdraft mass fluxes, and entrainment) averaged over the population of shallow clouds, or a single deep convective cloud; and vertical transport, activation/resuspension, aqueous chemistry, and wet removal of aerosol and trace gases in warm clouds. Thesechanges have been implemented in both the WRF-Chem chemistry packages as well as the Kain-Fritsch cumulus parameterization that has been modified to better represent shallow convective clouds. Preliminary testing of the modified WRF-Chem has been completed using observations from the Cumulus Humilis Aerosol Processing Study (CHAPS) as well as a high-resolution simulation that does not include parameterized convection. The simulation results are used to investigate the impact of cloud-aerosol interactions on the regional scale transport of black carbon (BC), organic aerosol (OA), and sulfate aerosol. Based on the simulations presented here, changes in the column integrated BC can be as large as -50% when cloud-aerosol interactions are considered (due largely to wet removal), or as large as +35% for sulfate in non-precipitating conditions due to the sulfate production in the parameterized clouds. The modifications to WRF-Chem version 3.2.1 are found to account for changes in the cloud drop number concentration (CDNC) and changes in the chemical composition of cloud-drop residuals in a way that is consistent with observations collected during CHAPS. Efforts are currently underway to port the changes described here to WRF-Chem version 3.5, and it is anticipated that they will be included in a future public release of WRF-Chem.

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

    E-Print Network [OSTI]

    Wang, Chenxi

    2013-07-25T23:59:59.000Z

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

  20. Cloud Microphysical and Radiative Properties Derived from MODIS, VIRS, AVHRR, and GMS Data Over the Tropical Western Pacific

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

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

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

    SciTech Connect (OSTI)

    Dudhia, Jimy

    2013-03-12T23:59:59.000Z

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

  2. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

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

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-27T23:59:59.000Z

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore »scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  3. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

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

    Lu, Chunsong [Nanjing Univ. of Information Science and Technology (China). Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters; Chinese Acadamy of Sciences, Beijing (China); Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.; Liu, Yangang [Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.; Niu, Shengjie [Nanjing Univ. of Information Science and Technology (China). Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters; Endo, Satoshi [Brookhaven National Laboratory (BNL), Upton, NY (United States). Biological, Environmental and Climate Science Dept.

    2014-12-27T23:59:59.000Z

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  4. 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

  5. Semidirect Dynamical and Radiative Impact of North African Dust Transport on Lower Tropospheric Clouds over the Subtropical North Atlantic in CESM 1.0

    SciTech Connect (OSTI)

    DeFlorio, Mike; Ghan, Steven J.; Singh, Balwinder; Miller, Arthur J.; Cayan, Dan; Russell, Lynn M.; Somerville, Richard C.

    2014-07-16T23:59:59.000Z

    This study uses a century length pre-industrial climate simulation by the Community Earth System Model (CESM 1.0) to explore statistical relationships between dust, clouds and atmospheric circulation, and to suggest a dynamical, rather than microphysical, mechanism linking subtropical North Atlantic lower tropospheric cloud cover with North African dust transport. The length of the run allows us to account for interannual variability of dust emissions and transport downstream of North Africa in the model. CESM’s mean climatology and probability distribution of aerosol optical depth in this region agrees well with available AERONET observations. In addition, CESM shows strong seasonal cycles of dust burden and lower tropospheric cloud fraction, with maximum values occurring during boreal summer, when a strong correlation between these two variables exists downstream of North Africa over the subtropical North Atlantic. Calculations of Estimated Inversion Strength (EIS) and composites of EIS on high and low downstream North Africa dust months during boreal summer reveal that dust is likely increasing inversion strength over this region due to both solar absorption and reflection. We find no evidence for a microphysical link between dust and lower tropospheric clouds in this region. These results yield new insight over an extensive period of time into the complex relationship between North African dust and lower tropospheric clouds over the open ocean, which has previously been hindered by spatiotemporal constraints of observations. Our findings lay a framework for future analyses using sub-monthly data over regions with different underlying dynamics.

  6. 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

  7. 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

  8. Parameterization of Infrared Absorption in Midlatitude Cirrus Clouds

    SciTech Connect (OSTI)

    Sassen, Kenneth; Wang, Zhien; Platt, C.M.R.; Comstock, Jennifer M.

    2003-01-01T23:59:59.000Z

    Employing a new approach based on combined Raman lidar and millimeter-wave radar measurements and a parameterization of the infrared absorption coefficient {sigma}{sub a}(km{sup -1}) in terms of retrieved cloud microphysics, we derive a statistical relation between {sigma}{sub a} and cirrus cloud temperature. The relations {sigma}{sub a} = 0.3949 + 5.3886 x 10{sup -3} T + 1.526 x 10{sup -5} T{sup 2} for ambient temperature (T,{sup o}C), and {sigma}{sub a} = 0.2896 + 3.409 x 10{sup -3} T{sub m} for midcloud temperature (T{sub m}, {sup o}C), are found using a second order polynomial fit. Comparison with two {sigma}{sub a} versus T{sub m} relations obtained primarily from midlatitude cirrus using the combined lidar/infrared radiometer (LIRAD) approach reveals significant differences. However, we show that this reflects both the previous convention used in curve fitting (i. e., {sigma}{sub a} {yields} 0 at {approx} 80 C), and the types of clouds included in the datasets. Without such constraints, convergence is found in the three independent remote sensing datasets within the range of conditions considered valid for cirrus (i.e., cloud optical depth {approx} 3.0 and T{sub m} < {approx}20 C). Hence for completeness we also provide reanalyzed parameterizations for a visible extinction coefficient {sigma}{sub a} versus T{sub m} relation for midlatitude cirrus, and a data sample involving cirrus that evolved into midlevel altostratus clouds with higher optical depths.

  9. 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.

  10. DEVELOPMENT OF IMPROVED TECHNIQUES FOR SATELLITE REMOTE SENSING OF CLOUDS AND RADIATION USING ARM DATA, FINAL REPORT

    SciTech Connect (OSTI)

    Minnis, Patrick [NASA Langley Research Center, Hampton, VA

    2013-06-28T23:59:59.000Z

    During the period, March 1997 – February 2006, the Principal Investigator and his research team co-authored 47 peer-reviewed papers and presented, at least, 138 papers at conferences, meetings, and workshops that were supported either in whole or in part by this agreement. We developed a state-of-the-art satellite cloud processing system that generates cloud properties over the Atmospheric Radiation (ARM) surface sites and surrounding domains in near-real time and outputs the results on the world wide web in image and digital formats. When the products are quality controlled, they are sent to the ARM archive for further dissemination. These products and raw satellite images can be accessed at http://cloudsgate2.larc.nasa.gov/cgi-bin/site/showdoc?docid=4&cmd=field-experiment-homepage&exp=ARM and are used by many in the ARM science community. The algorithms used in this system to generate cloud properties were validated and improved by the research conducted under this agreement. The team supported, at least, 11 ARM-related or supported field experiments by providing near-real time satellite imagery, cloud products, model results, and interactive analyses for mission planning, execution, and post-experiment scientific analyses. Comparisons of cloud properties derived from satellite, aircraft, and surface measurements were used to evaluate uncertainties in the cloud properties. Multiple-angle satellite retrievals were used to determine the influence of cloud structural and microphysical properties on the exiting radiation field.

  11. 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...

  12. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

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

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; et al

    2012-02-01T23:59:59.000Z

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently undermore »review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.« less

  13. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

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

    Baumgardner, Darrel [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico). Centro de Ciencias de la Atmosfera; Kok, Greg [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico). Centro de Ciencias de la Atmosfera; Avallone, L. [Univ. of Colorado, Boulder, CO (United States); Bansemer, A. [National Center for Atmospheric Research, Boulder, CO (United States); Borrmann, S. [Univ. of Maine (Germany); Brown, P. [Met Office, Exeter (United Kingdom); Bundke, U. [Univ. of Frankfurt (Germany); Chuang, P. Y. [Univ. of California, Santa Cruz, CA (United States); Cziczo, D. [Massachusetts Institute of Technology, Cambridge, MA (United States); Field, P. [Met Office, Exeter (United Kingdom); Gallagher, M. [Univ. of Manchester (United Kingdom); Gayet, J. -F. [CNRS/Univ. Blaise Pascal, Clermont-Ferrand (France). Lab. de Meteorologie Physique; Heymsfield, A. [National Center for Atmospheric Research, Boulder, CO (United States); Korolev, A. [Environment Canada (Canada). Cloud Physics and Severe Weather Research Section; Kraemer, M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung Stratosphaere; McFarquhar, G. [Univ. of Illinois at Urbana-Champaign, IL (United States); Mertes, S. [Leibniz Inst. for Tropospheric Research, Leipzig (Germany); Moehler, O. [Karlsruhe Institute of Technology (Germany); Lance, S. [Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences, Climate Diagnostics Center; National Oceanic and Atmospheric Administration, Boulder, CO (United States); Lawson, P. [SPEC, Inc., Boulder, CO (United States); Petters, M. D. [North Carolina State Univ., Raleigh, NC (United States); Pratt, K. [Purdue Univ., West Lafayette, IN (United States); Roberts, G. [Scripps Oceanographic Inst., La Jolla, CA (United States); Rogers, D. [National Center for Atmospheric Research, Boulder, CO (United States); Stetzer, O. [ETH, Zurich (Switzerland). Inst. for Atmospheric and Climate Science; Stith, J. [National Center for Atmospheric Research, Boulder, CO (United States); Strapp, W. [Environment Canada (Canada). Cloud Physics and Severe Weather Research Section; Twohy, C. [Oregon State Univ., Corvallis, OR (United States); Wendisch, M. [Leipzig Univ. (Germany). LIM

    2012-02-01T23:59:59.000Z

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently under review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.

  14. 3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds

    E-Print Network [OSTI]

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

    2012-01-01T23:59:59.000Z

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

  15. 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

  16. 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

  17. Thunderstorm characteristics of cloud-to-ground lightning at the Kennedy Space Center, Florida: a study of lightning initiation signatures as indicated by Doppler radar

    E-Print Network [OSTI]

    Gremillion, Michael Shane

    1998-01-01T23:59:59.000Z

    , except for 1806-1824 UTC 58 29 Same as Fig. 27, except for 1830-1847 UTC 59 30 Radar echo tops for all categories of storms 95 31 Scatter diagram of mixed-phase reflectivity lapse rate and maximum reflectivity at the freezing level for all storms... Mexico. Taylor (1978) also found the center of activity to be associated with the supercooled cloud layer between the regions of ? 5'C and ? 20'C. One theory of thunderstorm electrification supports the idea of an ice-related precipitation...

  18. 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

  19. The Ability of MM5 to Simulate Ice Clouds: Systematic Comparison between Simulated and Measured Fluxes and Lidar/Radar Profiles at SIRTA Atmospheric Observatory

    SciTech Connect (OSTI)

    Chiriaco, M.; Vautard, R.; Chepfer, H.; Haeffelin, M.; Wanherdrick, Y.; Morille, Y.; Protat, A.; Dudhia, J.

    2005-03-18T23:59:59.000Z

    Ice clouds play a major role in the radiative energy budget of the Earth-atmosphere system (Liou 1986). Their radiative effect is governed primarily by the equilibrium between their albedo and greenhouse effects. Both macrophysical and microphysical properties of ice clouds regulate this equilibrium. For quantifying the effect of these clouds onto climate and weather systems, they must be properly characterized in atmospheric models. In this paper we use remote-sensing measurements from the SIRTA ground based atmospheric observatory (Site Instrumental de Recherche par Teledetection Atmospherique, http://sirta.lmd.polytechnique.fr). Lidar and radar observations taken over 18 months are used, in order to gain statistical confidence in the model evaluation. Along this period of time, 62 days are selected for study because they contain parts of ice clouds. We use the ''model to observations'' approach by simulating lidar and radar signals from MM5 outputs. Other more classical variables such as shortwave and longwave radiative fluxes are also used. Four microphysical schemes, among which that proposed by Reisner et al. (1998) with original or modified parameterizations of particle terminal fall velocities (Zurovac-Jevtic and Zhang 2003, Heymsfield and Donner 1990), and the simplified Dudhia (1989) scheme are evaluated in this study.

  20. 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...

  1. 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.

  2. 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

  3. A General Analysis of Direct Dark Matter Detection: From Microphysics to Observational Signatures

    E-Print Network [OSTI]

    Dent, James B; Newstead, Jayden L; Sabharwal, Subir

    2015-01-01T23:59:59.000Z

    Beginning with a set of simplified models for spin-0, spin-$\\half$, and spin-1 dark matter candidates using completely general Lorentz invariant and renormalizable Lagrangians, we derive the full set of non-relativistic operators and nuclear matrix elements relevant for direct detection of dark matter, and use these to calculate rates and recoil spectra for scattering on various target nuclei. This allows us to explore what high energy physics constraints might be obtainable from direct detection experiments, what degeneracies exist, which operators are ubiquitous and which are unlikely or sub-dominant. We find that there are operators which are common to all spins as well operators which are unique to spin-$\\half$ and spin-1 and elucidate two new operators which have not been previously considered. In addition we demonstrate how recoil energy spectra can distinguish fundamental microphysics if multiple target nuclei are used. Our work provides a complete roadmap for taking generic fundamental dark matter the...

  4. 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...

  5. 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...

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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...

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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

  18. Microphysics and dynamics of the Gamma-Ray Burst GRB 121024A

    E-Print Network [OSTI]

    Varela, K; Greiner, J; Schady, P; Elliott, J; Sudilovsky, V; Krühler, T; Bolmer, J; Knust, F; Agurto, C; Azagra, F; Belloche, A; Bertoldi, F; De Breuck, C; Delvaux, C; Filgas, R; Graham, J; Guelbenzu, A Nicuesa; Kann, D A; Klose, S; Menten, K M; Rau, A; Rossi, A; Schmidl, S; Schuller, F; Schweyer, T; Tanga, M; Weiss, A; Wiseman, P; Wyrowski, F

    2015-01-01T23:59:59.000Z

    Using multi-epoch broad-band observations of the GRB 121024A afterglow, we measure the three characteristic break frequencies of the synchrotron spectrum. We use 6 epochs of combined XRT and GROND data to constrain the temporal slope, the dust extinction and the spectral slope with high accuracy. Two further epochs of combined data from XRT, GROND, APEX, CARMA and EVLA are used to set constraints on the break frequencies and therefore on the micro-physical and dynamical parameters. The XRT and GROND light curves show a simultaneous break at around 42 ks. No spectral evolution is observed between the afterglow SEDs before and after the break. As a result, the crossing of the synchrotron cooling break is not suitable as an explanation for the break in the light curve. The multi-wavelength data give us a unique opportunity to discern between two plausible scenarios explaining the break: the end of energy injection and a jet break. The observations are explained by two possible scenarios, a jet break and an energ...

  19. A General Analysis of Direct Dark Matter Detection: From Microphysics to Observational Signatures

    E-Print Network [OSTI]

    James B. Dent; Lawrence M. Krauss; Jayden L. Newstead; Subir Sabharwal

    2015-05-12T23:59:59.000Z

    Beginning with a set of simplified models for spin-0, spin-$\\half$, and spin-1 dark matter candidates using completely general Lorentz invariant and renormalizable Lagrangians, we derive the full set of non-relativistic operators and nuclear matrix elements relevant for direct detection of dark matter, and use these to calculate rates and recoil spectra for scattering on various target nuclei. This allows us to explore what high energy physics constraints might be obtainable from direct detection experiments, what degeneracies exist, which operators are ubiquitous and which are unlikely or sub-dominant. We find that there are operators which are common to all spins as well operators which are unique to spin-$\\half$ and spin-1 and elucidate two new operators which have not been previously considered. In addition we demonstrate how recoil energy spectra can distinguish fundamental microphysics if multiple target nuclei are used. Our work provides a complete roadmap for taking generic fundamental dark matter theories and calculating rates in direct detection experiments. This provides a useful guide for experimentalists designing experiments and theorists developing new dark matter models.

  20. Midlatitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Jensen, MP; Petersen, WA; Del Genio, AD; Giangrande, SE; Heymsfield, A; Heymsfield, G; Hou, AY; Kollias, P; Orr, B; Rutledge, SA; Schwaller, MR; Zipser, E

    2010-04-01T23:59:59.000Z

    Convective processes play a critical role in the Earth’s energy balance through the redistribution of heat and moisture in the atmosphere and subsequent impacts on the hydrologic cycle. Global observation and accurate representation of these processes in numerical models is vital to improving our current understanding and future simulations of Earth’s climate system. Despite improvements in computing power, current operational weather and global climate models are unable to resolve the natural temporal and spatial scales that are associated with convective and stratiform precipitation processes; therefore, they must turn to parameterization schemes to represent these processes. In turn, the physical basis for these parameterization schemes needs to be evaluated for general application under a variety of atmospheric conditions. Analogously, space-based remote sensing algorithms designed to retrieve related cloud and precipitation information for use in hydrological, climate, and numerical weather prediction applications often rely on physical “parameterizations” that reliably translate indirectly related instrument measurements to the physical quantity of interest (e.g., precipitation rate). Importantly, both spaceborne retrieval algorithms and model convective parameterization schemes traditionally rely on field campaign data sets as a basis for evaluating and improving the physics of their respective approaches. The Midlatitude Continental Convective Clouds Experiment (MC3E) will take place in central Oklahoma during the April–May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration’s (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that have never before been available. Several different components of convective cloud and precipitation processes tangible to both the convective parameterization and precipitation retrieval algorithm problem are targeted, such as preconvective environment and convective initiation, updraft/downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, spatial and temporal variability of precipitation, influence on the environment and radiation, and a detailed description of the large-scale forcing.

  1. 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...

  2. Chapter 3: Evaluating the impacts of carbonaceous aerosols on clouds and climate

    SciTech Connect (OSTI)

    Menon, Surabi; Del Genio, Anthony D.

    2007-09-03T23:59:59.000Z

    Any attempt to reconcile observed surface temperature changes within the last 150 years to changes simulated by climate models that include various atmospheric forcings is sensitive to the changes attributed to aerosols and aerosol-cloud-climate interactions, which are the main contributors that may well balance the positive forcings associated with greenhouse gases, absorbing aerosols, ozone related changes, etc. These aerosol effects on climate, from various modeling studies discussed in Menon (2004), range from +0.8 to -2.4 W m{sup -2}, with an implied value of -1.0 W m{sup -2} (range from -0.5 to -4.5 W m{sup -2}) for the aerosol indirect effects. Quantifying the contribution of aerosols and aerosol-cloud interactions remain complicated for several reasons some of which are related to aerosol distributions and some to the processes used to represent their effects on clouds. Aerosol effects on low lying marine stratocumulus clouds that cover much of the Earth's surface (about 70%) have been the focus of most of prior aerosol-cloud interaction effect simulations. Since cumulus clouds (shallow and deep convective) are short lived and cover about 15 to 20% of the Earth's surface, they are not usually considered as radiatively important. However, the large amount of latent heat released from convective towers, and corresponding changes in precipitation, especially in biomass regions due to convective heating effects (Graf et al. 2004), suggest that these cloud systems and aerosol effects on them, must be examined more closely. The radiative heating effects for mature deep convective systems can account for 10-30% of maximum latent heating effects and thus cannot be ignored (Jensen and Del Genio 2003). The first study that isolated the sensitivity of cumulus clouds to aerosols was from Nober et al. (2003) who found a reduction in precipitation in biomass burning regions and shifts in circulation patterns. Aerosol effects on convection have been included in other models as well (cf. Jacobson, 2002) but the relative impacts on convective and stratiform processes were not separated. Other changes to atmospheric stability and thermodynamical quantities due to aerosol absorption are also known to be important in modifying cloud macro/micro properties. Linkages between convection and boreal biomass burning can also impact the upper troposphere and lower stratosphere, radiation and cloud microphysical properties via transport of tropospheric aerosols to the lower stratosphere during extreme convection (Fromm and Servranckx 2003). Relevant questions regarding the impact of biomass aerosols on convective cloud properties include the effects of vertical transport of aerosols, spatial and temporal distribution of rainfall, vertical shift in latent heat release, phase shift of precipitation, circulation and their impacts on radiation. Over land surfaces, a decrease in surface shortwave radiation ({approx} 3-6 W m{sup -2} per decade) has been observed between 1960 to 1990, whereas, increases of 0.4 K in land temperature during the same period that occurred have resulted in speculations that evaporation and precipitation should also have decreased (Wild et al. 2004). However, precipitation records for the same period over land do not indicate any significant trend (Beck et al. 2005). The changes in precipitation are thought to be related to increased moisture advection from the oceans (Wild et al. 2004), which may well have some contributions from aerosol-radiation-convection coupling that could modify circulation patterns and hence moisture advection in specific regions. Other important aspects of aerosol effects, besides the direct, semi-direct, microphysical and thermodynamical impacts include alteration of surface albedos, especially snow and ice covered surfaces, due to absorbing aerosols. These effects are uncertain (Jacobson, 2004) but may produce as much as 0.3 W m{sup -2} forcing in the Northern hemisphere that could contribute to melting of ice and permafrost and change in the length of the season (e.g. early arrival of Spring

  3. 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...

  4. 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.

  5. 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...

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. Stratocumulus Clouds ROBERT WOOD

    E-Print Network [OSTI]

    Wood, Robert

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

  16. 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

  17. 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...

  18. 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

  19. 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

  20. Assessment of Uncertainty in Cloud Radiative Effects and Heating Rates through Retrieval Algorithm Differences: Analysis using 3-years of ARM data at Darwin, Australia

    SciTech Connect (OSTI)

    Comstock, Jennifer M.; Protat, Alain; McFarlane, Sally A.; Delanoe, Julien; Deng, Min

    2013-05-22T23:59:59.000Z

    Ground-based radar and lidar observations obtained at the Department of Energy’s Atmospheric Radiation Measurement Program’s Tropical Western Pacific site located in Darwin, Australia are used to retrieve ice cloud properties in anvil and cirrus clouds. Cloud microphysical properties derived from four different retrieval algorithms (two radar-lidar and two radar only algorithms) are compared by examining mean profiles and probability density functions of effective radius (Re), ice water content (IWC), extinction, ice number concentration, ice crystal fall speed, and vertical air velocity. Retrieval algorithm uncertainty is quantified using radiative flux closure exercises. The effect of uncertainty in retrieved quantities on the cloud radiative effect and radiative heating rates are presented. Our analysis shows that IWC compares well among algorithms, but Re shows significant discrepancies, which is attributed primarily to assumptions of particle shape. Uncertainty in Re and IWC translates into sometimes-large differences in cloud radiative effect (CRE) though the majority of cases have a CRE difference of roughly 10 W m-2 on average. These differences, which we believe are primarily driven by the uncertainty in Re, can cause up to 2 K/day difference in the radiative heating rates between algorithms.

  1. 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.

  2. Ensemble Kalman Filter Analyses of the 2930 May 2004 Oklahoma Tornadic Thunderstorm Using One-and Two-Moment Bulk Microphysics Schemes,

    E-Print Network [OSTI]

    Xue, Ming

    (KOUN), is used to assess the quality of the analysis. Analyzed reflectivity and radial velocity Surveillance Radar-1988 Doppler (WSR-88D) are assimilated and a po- larimetric WSR-88D in Norman, Oklahoma- fluence the evolution of convective systems, yet many complex microphysical processes and their effects

  3. Aerosol-cloud Interactions from Urban, Regional, to Global Scales

    E-Print Network [OSTI]

    Wang, Yuan

    2013-07-30T23:59:59.000Z

    the physical mechanism for the precipitation and lightning enhancement in the Guangzhou megacity area, showing more efficient mixed phase processes and intensified convection under the polluted aerosol condition. Sensitivity modeling experiments...

  4. 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

  5. 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

  6. 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 ...

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Effects of the microphysical Equation of State in the mergers of magnetized Neutron Stars With Neutrino Cooling

    E-Print Network [OSTI]

    Palenzuela, C; Neilsen, D; Lehner, L; Caballero, O L; O'Connor, E; Anderson, M

    2015-01-01T23:59:59.000Z

    We study the merger of binary neutron stars using different realistic, microphysical nuclear equations of state, as well as incorporating magnetic field and neutrino cooling effects. In particular, we concentrate on the influence of the equation of state on the gravitational wave signature and also on its role, in combination with cooling and electromagnetic effects, in determining the properties of the hypermassive neutron star resulting from the merger, the production of neutrinos, and the characteristics of ejecta from the system. The ejecta we find are consistent with other recent studies that find soft equations of state produce more ejecta than stiffer equations of state. Moreover, the degree of neutron richness increases for softer equations of state. In light of reported kilonova observations (associated to GRB~130603B and GRB~060614) and the discovery of relatively low abundances of heavy, radioactive elements in deep sea deposits (with respect to possible production via supernovae), we speculate tha...

  13. 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...

  14. Global Distribution and Climate Forcing of Marine Organic Aerosol - Part 2: Effects on Cloud Properties and Radiative Forcing

    SciTech Connect (OSTI)

    Gantt, Brett; Xu, Jun; Meskhidze, N.; Zhang, Yang; Nenes, Athanasios; Ghan, Steven J.; Liu, Xiaohong; Easter, Richard C.; Zaveri, Rahul A.

    2012-07-25T23:59:59.000Z

    A series of simulations with the Community Atmosphere Model version 5 (CAM5) with a 7-mode Modal Aerosol Model were conducted to assess the changes in cloud microphysical properties and radiative forcing resulting from marine organic aerosols. Model simulations show that the anthropogenic aerosol indirect forcing (AIF) predicted by CAM5 is decreased in absolute magnitude by up to 0.09 Wm{sup -2} (7 %) when marine organic aerosols are included. Changes in the AIF from marine organic aerosols are associated with small global increases in low-level incloud droplet number concentration and liquid water path of 1.3 cm{sup -3} (1.5 %) and 0.22 gm{sup -2} (0.5 %), respectively. Areas especially sensitive to changes in cloud properties due to marine organic aerosol include the Southern Ocean, North Pacific Ocean, and North Atlantic Ocean, all of which are characterized by high marine organic emission rates. As climate models are particularly sensitive to the background aerosol concentration, this small but non-negligible change in the AIF due to marine organic aerosols provides a notable link for ocean-ecosystem marine low-level cloud interactions and may be a candidate for consideration in future earth system models.

  15. 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

  16. 3022 VOLUME 130M O N T H L Y W E A T H E R R E V I E W 2002 American Meteorological Society

    E-Print Network [OSTI]

    Wang, Yuqing

    -rain-only cloud microphysics scheme (WMRN) and two mixed-ice- phase cloud microphysics schemes, one of which has. Part II: Model Refinements and Sensitivity to Cloud Microphysics Parameterization* YUQING WANG, the use of explicit cloud microphysics becomes more and more attractive with cumulus parameterization

  17. Atmospheric aerosol microphysics: Formation, characterization, and interaction. Progress report, September 1, 1991--February 28, 1994

    SciTech Connect (OSTI)

    Marlow, W.H.

    1994-12-31T23:59:59.000Z

    This project conducts theoretical and computational studies of the physical transformation processes of aerosols which underlie their atmospheric formation, interaction, transport, and removal and derives results that contribute to improved capabilities for modelling aerosol physical and chemical evolution in support of the environmental component of the National Energy Strategy. The subject of study is submicrometer aerosol particles with primary focus upon the ultrafine fraction. This report summarizes technical progress during the first two and one-half years of the project. Results of calculations of equilibrium vapor pressures over adhering pairs of 50, 100, and 200 nm particles are reported showing substantial depression of equilibrium vapor pressure relative to isolated spheres. Calculations are given of collective, long-range intermolecular energies for irregular particles to be used for growth rate calculations for realistic particles. Molecular dynamic simulations of thermal collisions of small clusters with each other and with single atoms are presented as a function of cluster size in the range from 1 to 8 atoms. Calculations of aerosol condensation in which vapor depletion and heating effects are taken into account for atmospheric cloud nucleation modelling are reported.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Laboratory Investigation of Contact Freezing and the Aerosol to Ice Crystal Transformation Process

    SciTech Connect (OSTI)

    Shaw, Raymond A. [Michigan Technological University

    2014-10-28T23:59:59.000Z

    This project has been focused on the following objectives: 1. Investigations of the physical processes governing immersion versus contact nucleation, specifically surface-induced crystallization; 2. Development of a quadrupole particle trap with full thermodynamic control over the temperature range 0 to –40 °C and precisely controlled water vapor saturation ratios for continuous, single-particle measurement of the aerosol to ice crystal transformation process for realistic ice nuclei; 3. Understanding the role of ice nucleation in determining the microphysical properties of mixed-phase clouds, within a framework that allows bridging between laboratory and field measurements.

  13. The Mid-Latitude Continental Convective Clouds Experiment (MC3E)

    SciTech Connect (OSTI)

    Petersen,W.; Jensen,M.; Genio, A. D.; Giangrande, S.; Heymsfield, A.; Heymsfield, G.; Hou, A.; Kollias, P.; Orr, B.; Rutledge, S.; Schwaller, M.; Zipser, E.

    2010-03-15T23:59:59.000Z

    The Midlatitude Continental Convective Cloud Experiment (MC3E) will take place in central Oklahoma during the April-May 2011 period. The experiment is a collaborative effort between the U.S. Department of Energy Atmospheric Radition Measurement Program and the National Aeronautics and Space Administration's (NASA) Global Precipitation Measurement (GPM) mission Ground Validation program. The Intensive Observation Period leverages the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal is to provide the most complete characterization of convective cloud systems, precipitation and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall observations over land that have never before been available. Several different components of convective processes tangible to the convective parameterization problem are targeted such as, pre-convective environment and convective initiation, updraft / downdraft dynamics, condensate transport and detrainment, precipitation and cloud microphysics, influence on the environment and radiation and a detailed description of the large-scale forcing. MC3E will use a new multi-scale observing strategy with the participation of a network of distributed sensors (both passive and active). The approach is to document in 3-D not only the full spectrum of precipitation rates, but also clouds, winds and moisture in an attempt to provide a holistic view of convective clouds and their feedback with the environment. A goal is to measure cloud and precipitation transitions and environmental quantities that are important for satellite retrieval algorithms, convective parameterization in large-scale models and cloud-resolving model simulations. This will be accomplished through the deployment of several different elements that complement the existing (and soon to become available) ARM facilities: a network of radiosonde stations, NASA scanning multi-frequency/parameter radar systems at three different frequencies (Ka/Ku/S), high-altitude remote sensing and in situ aircraft, wind profilers and a network of surface disdrometers. In addition to these special MC3E instruments, there will be important new instrumentation deployed by DOE at the ARM site including: 3 networked scanning X-band radar systems, a C-band scanning radar, a dual wavelength (Ka/W) scanning cloud radar, a Doppler lidar and upgraded vertically pointing millimeter cloud radar (MMCR) and micropulse lidar (MPL).To fully describe the properties of precipitating cloud systems, both in situ and remote sensing airborne observations are necessary. The NASA GPM-funded University of North Dakota (UND) Citation will provide in situ observations of precipitation-sized particles, ice freezing nuclei and aerosol concentrations. As a complement to the UND Citation's in situ observations, the NASA ER-2 will provide a high altitude satellite simulator platform that carrying a Ka/Ku band radar and passive microwave radiometers (10-183 GHZ).

  14. 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

  15. 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

  16. Effects of the microphysical Equation of State in the mergers of magnetized Neutron Stars With Neutrino Cooling

    E-Print Network [OSTI]

    C. Palenzuela; S. L. Liebling; D. Neilsen; L. Lehner; O. L. Caballero; E. O'Connor; M. Anderson

    2015-05-07T23:59:59.000Z

    We study the merger of binary neutron stars using different realistic, microphysical nuclear equations of state, as well as incorporating magnetic field and neutrino cooling effects. In particular, we concentrate on the influence of the equation of state on the gravitational wave signature and also on its role, in combination with cooling and electromagnetic effects, in determining the properties of the hypermassive neutron star resulting from the merger, the production of neutrinos, and the characteristics of ejecta from the system. The ejecta we find are consistent with other recent studies that find soft equations of state produce more ejecta than stiffer equations of state. Moreover, the degree of neutron richness increases for softer equations of state. In light of reported kilonova observations (associated to GRB~130603B and GRB~060614) and the discovery of relatively low abundances of heavy, radioactive elements in deep sea deposits (with respect to possible production via supernovae), we speculate that a soft EoS might be preferred---because of its significant production of sufficiently neutron rich ejecta---if such events are driven by binary neutron star mergers. We also find that realistic magnetic field strengths, obtained with a sub-grid model tuned to capture magnetic amplification via the Kelvin-Helmholtz instability at merger, are generally too weak to affect the gravitational wave signature post-merger within a time scale of $\\approx 10$~ms but can have subtle effects on the post-merger dynamics.

  17. Dynamical evolution of neutrino--cooled accretion disks: detailed microphysics, lepton-driven convection, and global energetics

    E-Print Network [OSTI]

    William H. Lee; Enrico Ramirez-Ruiz; Dany Page

    2005-06-06T23:59:59.000Z

    We present a detailed, two dimensional numerical study of the microphysical conditions and dynamical evolution of accretion disks around black holes when neutrino emission is the main source of cooling. Such structures are likely to form after the gravitational collapse of massive rotating stellar cores, or the coalescence of two compact objects in a binary (e.g., the Hulse--Taylor system). The physical composition is determined self consistently by considering two regimes: neutrino--opaque and neutrino--transparent, with a detailed equation of state which takes into account neutronization, nuclear statistical equilibrium of a gas of free nucleons and alpha particles, blackbody radiation and a relativistic Fermi gas of arbitrary degeneracy. Various neutrino emission processes are considered, with electron/positron capture onto free nucleons providing the dominant contribution to the cooling rate. We find that important temporal and spatial scales, related to the optically thin/optically thick transition are present in the disk, and manifest themselves clearly in the energy output in neutrinos. This transition produces an inversion of the lepton gradient in the innermost regions of the flow which drives convective motions, and affects the density and disk scale height radial profiles. The electron fraction remains low in the region close to the black hole, and if preserved in an outflow, could give rise to heavy element nucleosynthesis. Our specific initial conditions arise from the binary merger context, and so we explore the implications of our results for the production of gamma ray bursts.

  18. 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

  19. 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, ...

  20. Development of a Detailed Microphysics Cirrus Model Tracking Aerosol Particles' Histories for Interpretation of the Recent INCA Campaign

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    radiation; the mag- nitude of this effect is controlled by their vertical struc- ture and particularly- tude of this effect. The net effect of these processes can lead to negative but also positive radiative Project (ISCCP) Re- gional Experiment (FIRE), the Subsonic Aircraft Con- trail and Cloud Effects Special

  1. 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...

  2. 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 ...

  3. 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...

  4. 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 ...

  5. 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

  6. 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

  7. 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

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

    E-Print Network [OSTI]

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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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...

  19. Interactive physically-based cloud simulation

    E-Print Network [OSTI]

    Overby, Derek Robert

    2002-01-01T23:59:59.000Z

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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Cloud Security: Issues and Concerns Pierangela Samarati*

    E-Print Network [OSTI]

    Samarati, Pierangela

    1 Cloud Security: Issues and Concerns Authors Pierangela Samarati* Universitŕ degli Studi di Milano, Italy sabrina.decapitani@unimi.it Keywords cloud security confidentiality integrity availability secure data storage and processing Summary The cloud has emerged as a successful computing paradigm

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    SciTech Connect (OSTI)

    Westwater, Edgeworth

    2011-05-06T23:59:59.000Z

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of this contract, we participated in another ARM-sponsored experiment at the NSA during February-March 2007. This experiment is called the Radiative Heating in Underexplored Bands Campaign (RHUBC) and the GSR was operated successfully for the duration of the campaign. One of the principal goals of the experiment was to provide retrievals of water vapor during PWV amounts less than 2 mm and to compare GSR data with ARM radiometers and radiosondes. A secondary goal was to compare the radiometric response of the microwave and millimeter wavelength radiometers to water and ice clouds. In this final report, we will include the separate progress reports for each of the three years of the project and follow with a section on major accomplishments of the project.

  14. 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.

  15. Journal of Quantitative Spectroscopy & Radiative Transfer 7980 (2003) 11711188

    E-Print Network [OSTI]

    Baum, Bryan A.

    .elsevier.com/locate/jqsrt The spectral signature of mixed-phase clouds composed of non-spherical ice crystals and spherical liquid and ice particles may be present. This is typically known as a "mixed-phase" cloud condition the bulk scattering properties of mixed-phase clouds by a linear weighting of the contributions of ice

  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. 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...

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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...

  17. 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 ...

  18. 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

  19. 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...

  20. 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,

  1. 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

  2. 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

  3. 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—

  4. 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...

  5. Electron Cloud Effects in Accelerators

    SciTech Connect (OSTI)

    Furman, M.A.

    2012-11-30T23:59:59.000Z

    Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  6. ARM - Lesson Plans: Making 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: National5Sales for4,645 3,625govInstrumentstdmadap Documentation TDMADAP : XDC documentationBarrow, Alaska OutreachMaking Clouds Outreach Home

  7. Sandia Energy - Cloud Computing Services

    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 Scienceand RequirementsCoatings Initiated at PNNL's Sequim BayCaptureCloud Computing Services

  8. CloneCloud: Boosting Mobile Device Applications Through Cloud Clone Execution

    E-Print Network [OSTI]

    Chun, Byung-Gon; Maniatis, Petros; Naik, Mayur

    2010-01-01T23:59:59.000Z

    Mobile applications are becoming increasingly ubiquitous and provide ever richer functionality on mobile devices. At the same time, such devices often enjoy strong connectivity with more powerful machines ranging from laptops and desktops to commercial clouds. This paper presents the design and implementation of CloneCloud, a system that automatically transforms mobile applications to benefit from the cloud. The system is a flexible application partitioner and execution runtime that enables unmodified mobile applications running in an application-level virtual machine to seamlessly off-load part of their execution from mobile devices onto device clones operating in a computational cloud. CloneCloud uses a combination of static analysis and dynamic profiling to optimally and automatically partition an application so that it migrates, executes in the cloud, and re-integrates computation in a fine-grained manner that makes efficient use of resources. Our evaluation shows that CloneCloud can achieve up to 21.2x s...

  9. Public Cloud B CarbonEmission

    E-Print Network [OSTI]

    Buyya, Rajkumar

    Sensors, Demand Prediction Power Capping, Green Software Services such as energy-efficient scientific) Request a Cloud service 4) Allocate service 5) Request service allocation 3) Request energy efficiency information Green Offer Directory 2) Request any `Green Offer' Routers Internet Green Broker #12;Cloud

  10. The CloudNets Network Virtualization Architecture

    E-Print Network [OSTI]

    Schmid, Stefan

    Nets Network Virtualization Architecture Johannes Grassler jgrassler@inet.tu-berlin.de 05. Februar, 2014 Johannes Grassler jgrassler@inet.tu-berlin.de The CloudNets Network Virtualization Architecture #12;..... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . ..... . .... . .... . Johannes Grassler jgrassler@inet.tu-berlin.de The CloudNets Network Virtualization Architecture #12

  11. 7, 80878111, 2007 Influence of cloud top

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 7, 8087­8111, 2007 Influence of cloud top variability on radiative transfer Richter, Barfus top variability from radar measurements on 3-D radiative transfer F. Richter 1 , K. Barfus 1 , F. H.richter@awi.de) 8087 #12;ACPD 7, 8087­8111, 2007 Influence of cloud top variability on radiative transfer Richter

  12. Verifiable Resource Accounting for Cloud Computing Services

    E-Print Network [OSTI]

    Maniatis, Petros

    Verifiable Resource Accounting for Cloud Computing Services Vyas Sekar Intel Labs Petros Maniatis Intel Labs ABSTRACT Cloud computing offers users the potential to reduce operating and capital expenses cause providers to incorrectly attribute resource consumption to customers or im- plicitly bear

  13. Compression of Antiproton Clouds for Antihydrogen Trapping

    E-Print Network [OSTI]

    G. B. Andresen; W. Bertsche; P. D. Bowe; C. C. Bray; E. Butler; C. L. Cesar; S. Chapman; M. Charlton; J. Fajans; M. C. Fujiwara; R. Funakoshi; D. R. Gill; J. S. Hangst; W. N. Hardy; R. S. Hayano; M. E. Hayden; R. Hydomako; M. J. Jenkins; L. V. Jorgensen; L. Kurchaninov; R. Lambo; N. Madsen; P. Nolan; K. Olchanski; A. Olin; A. Povilus; P. Pusa; F. Robicheaux; E. Sarid; S. Seif El Nasr; D. M. Silveira; J. W. Storey; R. I. Thompson; D. P. van der Werf; J. S. Wurtele; Y. Yamazaki

    2008-06-30T23:59:59.000Z

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile and its relation to that of the electron plasma.

  14. CLOUD COMPUTING INFRASTRUCTURE AND OPERATIONS PROGRAM

    E-Print Network [OSTI]

    Schaefer, Marcus

    theory and best practices, Cloud operations analytics, globally-responsive architecture, functional of Cloud infrastructures Best practices for building Infrastructure as a Service (IaaS), with an emphasis-distributed, responsive web application capable of massive scale with operational performance metrics. DePaul University

  15. Privacy in the Cloud Computing Era

    E-Print Network [OSTI]

    Narasayya, Vivek

    Privacy in the Cloud Computing Era A Microsoft Perspective November 2009 #12;The information information presented after the date of publication. This white paper is for informational purposes only. Microsoft Corp. · One Microsoft Way · Redmond, WA 98052-6399 · USA #12;Contents Cloud Computing and Privacy

  16. Cloud-integrated Storage What & Why 2StoreSimple White Pages: Shoring Up Infrastructure Weaknesses with Cloud Storage

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Cloud-integrated Storage ­ What & Why #12;2StoreSimple White Pages: Shoring Up Infrastructure Weaknesses with Cloud Storage Overview..........................................................................................................3 Enterprise-class storage platform

  17. 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: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t zManufacturing:DOE NationalCommitteeof3

  18. Magnetic Fields in Molecular Cloud Cores

    E-Print Network [OSTI]

    Shantanu Basu

    2004-10-22T23:59:59.000Z

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

  19. 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 ...

  20. ARM - Midlatitude Continental Convective Clouds

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

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

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

  1. Securely Managing Cryptographic Keys used within a Cloud Environment

    E-Print Network [OSTI]

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

  2. Proximity Graphs for Defining Surfaces over Point Clouds

    E-Print Network [OSTI]

    Behnke, Sven

    over Point Clouds Gabriel Zachmann University of Bonn Germany Jan Klein University of Paderborn Germany

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

    E-Print Network [OSTI]

    Graaf, Martin de

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

  4. CLOUD PHYSICS From aerosol-limited to invigoration

    E-Print Network [OSTI]

    Napp, Nils

    CLOUD PHYSICS From aerosol-limited to invigoration of warm convective clouds Ilan Koren,1 * Guy Dagan,1 Orit Altaratz1 Among all cloud-aerosol interactions, the invigoration effect is the most elusive. Most of the studies that do suggest this effect link it to deep convective clouds with a warm base

  5. Fault-Tolerant and Reliable Computation in Cloud Computing

    E-Print Network [OSTI]

    Deng, Jing

    Fault-Tolerant and Reliable Computation in Cloud Computing Jing Deng Scott C.-H. Huang Yunghsiang S, Taipei, 106 Taiwan. § Intelligent Automation, Inc., Rockville, MD, USA. Abstract-- Cloud computing of scientific computation in cloud computing. We investigate a cloud selection strategy to decompose the matrix

  6. How Mobility Increases Mobile Cloud Computing Processing Capacity

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    How Mobility Increases Mobile Cloud Computing Processing Capacity Anh-Dung Nguyen, Patrick S--In this paper, we address a important and still unanswered question in mobile cloud computing "how mobility the resilience of mobile cloud computing services. Keywords--Mobile cloud computing, mobility, quality of service

  7. IBM Tivoli Cloud Computing: Technical Enablement for IBM Business Partners

    E-Print Network [OSTI]

    IBM Tivoli Cloud Computing: Technical Enablement for IBM Business Partners Cloud computing is a key part of driving greater alignment between business and IT. IBM Service Management and Cloud Computing to the IBM technical community. IBM Cloud Computing Business Partner Technical Enablement Offering

  8. Cloud Condensation Nuclei (CCN) Analysis of Biogenic Secondary Organic Aerosol

    E-Print Network [OSTI]

    Collins, Gary S.

    Cloud Condensation Nuclei (CCN) Analysis of Biogenic Secondary Organic Aerosol Rachel L. Atlas1' gas-phase emissions and the aerosols they form (figure 6), including a cloud condensation nuclei Cloud condensation nuclei (CCN) are particles which water vapor condenses onto to form cloud droplets

  9. Precipitation scavenging, dry deposition, and resuspension. Volume 1: precipitation scavenging

    SciTech Connect (OSTI)

    Pruppacher, H.R.; Semonin, R.G.; Slinn, W.G.N.

    1983-01-01T23:59:59.000Z

    Papers are presented under the headings: cloud studies, precipitation chemistry, plume studies, gas scavenging, microphysics and models.

  10. The Experimental Cloud Lidar Pilot Study (ECLIPS) for cloud-radiation research

    SciTech Connect (OSTI)

    Platt, C.M.; Young, S.A. [Division of Atmospheric Research, Victoria (Australia)] [Division of Atmospheric Research, Victoria (Australia); Carswell, A.I.; Pal, S.R. [York Univ., North York, Ontario (Canada)] [York Univ., North York, Ontario (Canada); McCormick, M.P.; Winker, D.M. [NASA Langley Research Center, Hampton, VA (United States)] [NASA Langley Research Center, Hampton, VA (United States); DelGuasta, M.; Stefanutti, L. [Institute Ricerca Onde Elettromagnetiche, Florence (Italy)] [Institute Ricerca Onde Elettromagnetiche, Florence (Italy); Eberhard, W.L.; Hardesty, M. [NOAA Environmental Technology Lab., Boulder, CO (United States)] [and others] [NOAA Environmental Technology Lab., Boulder, CO (United States); and others

    1994-09-01T23:59:59.000Z

    The Experimental Cloud Lidar Pilot Study (ECLIPS) was initiated to obtain statistics on cloud-base height, extinction, optical depth, cloud brokenness, and surface fluxes. Two observational phases have taken place, in October-December 1989 and April-July 1991, with intensive 30-day periods selected within the two time intervals. Data are being archived at NASA Langley Research Center, and, once there, are readily available to the international scientific community. 43 refs., 13 figs., 4 tabs.

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

    E-Print Network [OSTI]

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

  12. Generated using version 3.0 of the official AMS LATEX template Computing and Partitioning Cloud Feedbacks using Cloud1

    E-Print Network [OSTI]

    Hartmann, Dennis

    Generated using version 3.0 of the official AMS LATEX template Computing and Partitioning Cloud Feedbacks using Cloud1 Property Histograms.2 Part II: Attribution to the Nature of Cloud Changes3 Mark D-103 Livermore, CA 94551 E-mail: zelinka1@llnl.gov 1 #12;ABSTRACT7 Cloud radiative kernels

  13. IEEE TRANSACTIONS ON CLOUD COMPUTING, VOL. XX, NO. X, XXXX 1 Cloud Federations in the Sky: Formation Game

    E-Print Network [OSTI]

    Grosu, Daniel

    IEEE TRANSACTIONS ON CLOUD COMPUTING, VOL. XX, NO. X, XXXX 1 Cloud Federations in the Sky federation, virtual machine, game theory. 1 INTRODUCTION CLOUDS are large-scale distributed computing sys (VM) instances. Cloud computing systems' ability to provide on de- mand access to always-on computing

  14. Retrievals of Cloud Fraction and Cloud Albedo from Surface-based Shortwave Radiation Measurements: A Comparison of 16 Year Measurements

    SciTech Connect (OSTI)

    Xie, Yu; Liu, Yangang; Long, Charles N.; Min, Qilong

    2014-07-27T23:59:59.000Z

    Ground-based radiation measurements have been widely conducted to gain information on clouds and the surface radiation budget; here several different techniques for retrieving cloud fraction (Long2006, Min2008 and XL2013) and cloud albedo (Min2008, Liu2011 and XL2013) from ground-based shortwave broadband and spectral radiation measurements are examined, and sixteen years of retrievals collected at the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site are compared. The comparison shows overall good agreement between the retrievals of both cloud fraction and cloud albedo, with noted differences however. The Long2006 and Min2008 cloud fractions are greater on average than the XL2013 values. Compared to Min2008 and Liu2011, the XL2013 retrieval of cloud albedo tends to be greater for thin clouds but smaller for thick clouds, with the differences decreasing with increasing cloud fraction. Further analysis reveals that the approaches that retrieve cloud fraction and cloud albedo separately may suffer from mutual contamination of errors in retrieved cloud fraction and cloud albedo. Potential influences of cloud absorption, land-surface albedo, cloud structure, and measurement instruments are explored.

  15. Development of an aerosol microphysical module: Aerosol Two-dimensional bin module for foRmation and Aging Simulation (ATRAS)

    SciTech Connect (OSTI)

    Matsui, H.; Koike, Makoto; Kondo, Yutaka; Fast, Jerome D.; Takigawa, M.

    2014-09-30T23:59:59.000Z

    Number concentrations, size distributions, and mixing states of aerosols are essential parameters for accurate estimation of aerosol direct and indirect effects. In this study, we developed an aerosol module, designated Aerosol Two-dimensional bin module for foRmation and Aging Simulation (ATRAS), that can represent these parameters explicitly by considering new particle formation (NPF), black carbon (BC) aging, and secondary organic aerosol (SOA) processes. A two-dimensional bin representation is used for particles with dry diameters from 40 nm to 10 µm to resolve both aerosol size (12 bins) and BC mixing state (10 bins) for a total of 120 bins. The particles with diameters from 1 to 40 nm are resolved using an additional 8 size bins to calculate NPF. The ATRAS module was implemented in the WRF-chem model and applied to examine the sensitivity of simulated mass, number, size distributions, and optical and radiative parameters of aerosols to NPF, BC aging and SOA processes over East Asia during the spring of 2009. BC absorption enhancement by coating materials was about 50% over East Asia during the spring, and the contribution of SOA processes to the absorption enhancement was estimated to be 10 – 20% over northern East Asia and 20 – 35% over southern East Asia. A clear north-south contrast was also found between the impacts of NPF and SOA processes on cloud condensation nuclei (CCN) concentrations: NPF increased CCN concentrations at higher supersaturations (smaller particles) over northern East Asia, whereas SOA increased CCN concentrations at lower supersaturations (larger particles) over southern East Asia. Application of ATRAS to East Asia also showed that the impact of each process on each optical and radiative parameter depended strongly on the process and the parameter in question. The module can be used in the future as a benchmark model to evaluate the accuracy of simpler aerosol models and examine interactions between NPF, BC aging, and SOA processes under different meteorological conditions and emissions.

  16. Pre-Cloud Aerosol, Cloud Droplet Concentration, and Cloud Condensation Nuclei from the VAMOS Ocean-Cloud-Atmosphere Land Study (VOCALS) Field Campaign First Quarter 2010 ASR Program Metric Report

    SciTech Connect (OSTI)

    Kleinman, LI; Springston, SR; Daum, PH; Lee, Y-N; Sedlacek, AJ; Senum, G; Wang, J

    2011-08-31T23:59:59.000Z

    In this, the first of a series of Program Metric Reports, we (1) describe archived data from the DOE G-1 aircraft, (2) illustrate several relations between sub-cloud aerosol, CCN, and cloud droplets pertinent to determining the effects of pollutant sources on cloud properties, and (3) post to the data archive an Excel spreadsheet that contains cloud and corresponding sub-cloud data.

  17. 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.

  18. EVENT CLOUDS : lighter than air architectural structures

    E-Print Network [OSTI]

    Peydro Duclos, Ignacio

    2014-01-01T23:59:59.000Z

    EVENT CLOUD is a versatile covering system that allows events to happen independently to weather conditions. It consists of a lighter than air pneumatic structure, filled either with helium or hot air, that covers spaces ...

  19. Uranus at equinox: Cloud morphology and dynamics

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

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

  20. Enabling Scalable Cloud Computing | Argonne Leadership Computing...

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

    Enabling Scalable Cloud Computing Event Sponsor: Mathematics and Computer Science Division Start Date: Apr 9 2015 - 11:00am BuildingRoom: Building 240Room 4301 Location: Argonne...

  1. Factors shaping the future of Cloud Computing

    E-Print Network [OSTI]

    Francis, Steven (Steven Douglas)

    2011-01-01T23:59:59.000Z

    Many different forces are currently shaping the future of the Cloud Computing Market. End user demand and end user investment in existing technology are important drivers. Vendor innovation and competitive strategy are ...

  2. QER- Comment of Cloud Peak Energy Inc

    Broader source: Energy.gov [DOE]

    Dear Ms Pickett Please find attached comments from Cloud Peak Energy as input to the Department of Energy’s Quadrennial Energy Review. If possible I would appreciate a confirmation that this email has been received Thank you.

  3. HPC CLOUD APPLIED TO LATTICE OPTIMIZATION

    SciTech Connect (OSTI)

    Sun, Changchun; Nishimura, Hiroshi; James, Susan; Song, Kai; Muriki, Krishna; Qin, Yong

    2011-03-18T23:59:59.000Z

    As Cloud services gain in popularity for enterprise use, vendors are now turning their focus towards providing cloud services suitable for scientific computing. Recently, Amazon Elastic Compute Cloud (EC2) introduced the new Cluster Compute Instances (CCI), a new instance type specifically designed for High Performance Computing (HPC) applications. At Berkeley Lab, the physicists at the Advanced Light Source (ALS) have been running Lattice Optimization on a local cluster, but the queue wait time and the flexibility to request compute resources when needed are not ideal for rapid development work. To explore alternatives, for the first time we investigate running the Lattice Optimization application on Amazon's new CCI to demonstrate the feasibility and trade-offs of using public cloud services for science.

  4. Exploiting weather forecast data for cloud detection 

    E-Print Network [OSTI]

    Mackie, Shona

    2009-01-01T23:59:59.000Z

    Accurate, fast detection of clouds in satellite imagery has many applications, for example Numerical Weather Prediction (NWP) and climate studies of both the atmosphere and of the Earth’s surface temperature. Most ...

  5. Aircraft induced cirrus cloud First year report

    E-Print Network [OSTI]

    Oxford, University of

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

  6. Ignition of Aluminum Particles and Clouds

    SciTech Connect (OSTI)

    Kuhl, A L; Boiko, V M

    2010-04-07T23:59:59.000Z

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

  7. The arc cloud complex: a case study

    E-Print Network [OSTI]

    Miller, Robert Loren

    1984-01-01T23:59:59.000Z

    THE ARC CLOUD COMPLEX: A CASE STUDY A Thesis by ROBERT LOREN MILLER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1984 Major Subject...: Meteorology THE ARC CLOUD COMPLEX; A CASE STUDY A Thesis by ROBERT LOREN MILLER Approved as to style and content by: Kenneth C. Brundidge (Chairman of Committee) Walter K. Henry (Member) Marshall ~ Mcparland (Member) James R. Scog s (Head...

  8. The Energy Efficiency Potential of Cloud-Based Software: A U.S. Case Study

    E-Print Network [OSTI]

    Masanet, Eric

    2014-01-01T23:59:59.000Z

    Technology:  Can  Cloud  Computing  Enable  Carbon  environment/resources/Can_Cloud_Computing_Enable_Carbon_AbatTechnology:  Can  Cloud  Computing  Enable  Carbon  

  9. Fate of Acids in Clouds 1. Combination with bases dissolved in clouds: acids neutralized

    E-Print Network [OSTI]

    Schofield, Jeremy

    problems. E#11;ects of Acid Rain 1. Vegetation: SO 2 is toxic to plants #15; Leaves damaged below pH 3 rain { Athens and Rome cathedrals and statues: pollution leads to acid rain #15; SteelFate of Acids in Clouds 1. Combination with bases dissolved in clouds: acids neutralized NH 3 (g

  10. Cloud water contents and hydrometeor sizes during the FIRE Arctic Clouds Experiment

    E-Print Network [OSTI]

    Shupe, Matthew

    of radiometers at an ice station frozen into the drifting ice pack of the Arctic Ocean. The NASA/FIRE Arctic- dependent water contents and hydrometeor sizes for all-ice and all-liquid clouds. For the spring and early summer period, all-ice cloud retrievals showed a mean particle diameter of about 60 m and ice water

  11. X-1 ROEBELING ET AL.: SEVIRI & AVHRR CLOUD PROPERTY RETRIEVALS Cloud property retrievals for climate monitoring

    E-Print Network [OSTI]

    Stoffelen, Ad

    Generation (METEOSAT-8) and the Advanced Very High Resolution Radiometer (AVHRR) onboard the National Oceanic a consistent and high quality dataset of SEVIRI and AVHRR retrieved cloud properties for climate research studies. Clouds strongly modulate the energy balance of the Earth and its atmosphere through

  12. CloudCmp: Shopping for a Cloud Made Easy Ang Li Xiaowei Yang

    E-Print Network [OSTI]

    Zhang, Ming

    benchmarking results on three representative cloud providers. These results show that the performance and costs interfaces, and benchmarks the performance and costs of these services. It then expresses an applicationCmp and highlight the main technical chal- lenges. CloudCmp includes a set of benchmarking tools that compare

  13. Aircraft Observations of Sub-cloud Aerosol and Convective Cloud Physical Properties

    E-Print Network [OSTI]

    Axisa, Duncan

    2011-02-22T23:59:59.000Z

    This research focuses on aircraft observational studies of aerosol-cloud interactions in cumulus clouds. The data were collected in the summer of 2004, the spring of 2007 and the mid-winter and spring of 2008 in Texas, central Saudi Arabia...

  14. The Radiative, Cloud, and Thermodynamic Properties of the Major Tropical Western Pacific Cloud Regimes

    E-Print Network [OSTI]

    Jakob, Christian

    's surface. Other effects include the release and consumption of latent heat related to phase changes in the tropical western Pacific (TWP). A cluster analysis is applied to 2 yr of daytime-only data from the International Satellite Cloud Climatology Project (ISCCP) to identify four major cloud regimes in the TWP region

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

    E-Print Network [OSTI]

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

    2015-01-01T23:59:59.000Z

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

  16. advanced analytical simulation: Topics by E-print Network

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

    in Drizzling Stratiform Clouds Based on Large-Eddy Simulations University of Kansas - KU ScholarWorks Summary: Cloud microphysical parameterizations and retrievals...

  17. Triggered star formation in the Magellanic Clouds

    E-Print Network [OSTI]

    B. G. Elmegreen; J. Palous; Kenji Bekki

    2006-01-01T23:59:59.000Z

    Abstract. We discuss how tidal interaction between the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the Galaxy triggers galaxy-wide star formation in the Clouds for the last ? 0.2 Gyr based on our chemodynamical simulations on the Clouds. Our simulations demonstrate that the tidal interaction induces the formation of asymmetric spiral arms with high gas densities and consequently triggers star formation within the arms in the LMC. Star formation rate in the present LMC is significantly enhanced just above the eastern edge of the LMC’s stellar bar owing to the tidal interaction. The location of the enhanced star formation is very similar to the observed location of 30 Doradus, which suggests that the formation of 30 Doradus is closely associated with the last Magellanic collision about 0.2 Gyr ago. The tidal interaction can dramatically compress gas initially within the outer part of the SMC so that new stars can be formed from the gas to become intergalactic young stars in the inter-Cloud region (e.g., the Magellanic Bridge). The metallicity distribution function of the newly formed stars in the Magellanic Bridge has a peak of [Fe/H] ? ?0.8, which is significantly lower than the stellar metallicity of the SMC.

  18. Study of Electron Cloud for MEIC

    SciTech Connect (OSTI)

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

    2011-09-01T23:59:59.000Z

    The Medium Energy Electron Ion Collider (MEIC) at Jefferson Lab has been envisioned as a future high energy particle accelerator beyond the 12 GeV upgrade of the existing Continuous Electron Beam Accelerator Facility (CEBAF). Synchrotron radiation from the closely spaced proton bunches in MEIC can generate photoelectrons inside the vacuum chamber and cause secondary emission due to multipacting in the presence of beam's electric field. This phenomenon can lead to fast build up of electron density, known as electron cloud effect - resulting into beam instability coupled to multi-bunches in addition to a single bunch. For MEIC, the estimated threshold value of the electron-cloud density is approximately 5 x 10{sup 12} m{sup -3}. In this paper, we would like to report the self-consistent simulation studies of electron cloud formation for MEIC. The code has been benchmarked against the published data of electron cloud effects observed in LHC. Our first simulations predict increase of electron clouds with the increase of repetition rate. The detailed simulations are under progress and will be reported.

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

    E-Print Network [OSTI]

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

  20. Electron Cloud observation in the LHC

    E-Print Network [OSTI]

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

    2011-01-01T23:59:59.000Z

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

  1. High-velocity clouds: a diverse phenomenon

    E-Print Network [OSTI]

    B. P. Wakker

    2001-09-13T23:59:59.000Z

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

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

    E-Print Network [OSTI]

    Muńoz, Francesc

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

  3. CO and IRAS detection of an intermediate-velocity cloud

    SciTech Connect (OSTI)

    Desert, F.X.; Bazell, D.; Blitz, L. (Paris Observatoire, Meudon (France) Space Telescope Science Institute, Baltimore, MD (USA) Maryland Univ., College Park (USA))

    1990-06-01T23:59:59.000Z

    In the course of a radio survey of high-Galactic-latitude clouds, CO emission was detected at the position l = 210.8 deg and b = 63.1 deg with an LSR velocity of -39 km/sec. This molecular cloud constitutes the third one with an unusually large absolute velocity at these latitudes, as compared with the 5.4-km/sec cloud-to-cloud velocity dispersion of the high-latitude molecular clouds. The position is coincident with an H I intermediate-velocity cloud (GHL 11, Verschuur H, OLM 268) and the IR-excess cloud 306 in the list by Desert et al. (1988). This cloud is clearly detected at all four IRAS wavelengths and has warmer colors than the local ISM. 27 refs.

  4. Cloud computing and its implications for organizational design and performance

    E-Print Network [OSTI]

    Farahani Rad, Ali

    2013-01-01T23:59:59.000Z

    Cloud computing has been at the center of attention for a while now. This attention is directed towards different aspects of this concept which concern different stakeholders from IT companies to cloud adopters to simple ...

  5. The study of cirrus clouds using airborne and satellite data 

    E-Print Network [OSTI]

    Meyer, Kerry Glynne

    2004-09-30T23:59:59.000Z

    (AVIRIS) and the Moderate-resolution Infrared Spectroradiometer (MODIS), scientists now have an unprecedented ability to study cirrus clouds. To aid in the understanding of such clouds, a significant study of cirrus radiative properties has been undertaken...

  6. Cloud computing adoption model for governments and large enterprises

    E-Print Network [OSTI]

    Trivedi, Hrishikesh

    2013-01-01T23:59:59.000Z

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

  7. Cloud computing : implications for enterprise software vendors (ESV)

    E-Print Network [OSTI]

    Francis, Leonard, S.M. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    'Cloud computing', is a broad concept and in general is a term used for internet-based computing resources that are in an unspecified remote location or locations and that are flexible and fungible. Clouds provide a wide ...

  8. Transition to cloud computing in healthcare information systems

    E-Print Network [OSTI]

    Ren, Haiying, S.M. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    This thesis is a study on the adoption of cloud computing in healthcare information technology industry. It provides a guideline for people who are trying to bring cloud computing into healthcare information systems through ...

  9. A Survey on Approaches for Interoperability and Portability of Cloud Computing Services

    E-Print Network [OSTI]

    Petrakis, Euripides G.M.

    A Survey on Approaches for Interoperability and Portability of Cloud Computing Services Kostas.sotiriadis, petrakis}@intelligence.tuc.gr Keywords: Cloud computing, cloud interoperability, cloud portability Abstract: Over the recent years, the rapid development of Cloud Computing has driven to a large market of cloud

  10. TGRS-2010-00092.R1 1 Abstract--Cloud properties were retrieved by applying the

    E-Print Network [OSTI]

    Dong, Xiquan

    cover (~59%) is divided equally between liquid and ice clouds. Global mean cloud effective heights , respectively, for liquid clouds and 8.3 km, 12.7, 52.2 µm, and 230 gm-2 for ice clouds. Cloud droplet effective radiation processes requires determination of cloud property distributions and the radiation budget

  11. 2012 MELLANOX TECHNOLOGIES 1 The Interconnect is the Cloud

    E-Print Network [OSTI]

    Schuster, Assaf

    IT costs from CAPEX to OPEX IT Efficiency and Business Agility Hybrid Cloud Compute and Storage Resource

  12. Information Security Management System for Microsoft's Cloud Infrastructure

    E-Print Network [OSTI]

    Chaudhuri, Surajit

    Information Security Management System for Microsoft's Cloud Infrastructure Online Services ......................................................................................................................................................................................1 Information Security Management System.......................................................................................................................7 Information Security Management Forum

  13. Intrinsic Shapes of Molecular Cloud Cores

    E-Print Network [OSTI]

    C. E. Jones; Shantanu Basu; John Dubinski

    2001-01-08T23:59:59.000Z

    We conduct an analysis of the shapes of molecular cloud cores using recently compiled catalogs of observed axis ratios of individual cores mapped in ammonia or through optical selection. We apply both analytical and statistical techniques to deproject the observed axis ratios in order to determine the true distribution of cloud core shapes. We find that neither pure oblate nor pure prolate cores can account for the observed distribution of core shapes. Intrinsically triaxial cores produce distributions which agree with observations. The best-fit triaxial distribution contains cores which are more nearly oblate than prolate.

  14. 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.

  15. LIDAR, Point Clouds, and their Archaeological Applications

    SciTech Connect (OSTI)

    White, Devin A [ORNL

    2013-01-01T23:59:59.000Z

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

  16. Radion clouds around evaporating black holes

    E-Print Network [OSTI]

    J. R. Morris

    2009-09-03T23:59:59.000Z

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

  17. Dynamics of Finite Dust Clouds in a Magnetized Anodic Plasma

    SciTech Connect (OSTI)

    Piel, A.; Pilch, I.; Trottenberg, T. [Institute for Experimental and Applied Physics, Christian-Albrechts University, D-24098 Kiel (Germany); Koepke, M. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26505-6315 (United States)

    2008-09-07T23:59:59.000Z

    The response to an external modulation voltage of small dust clouds confined in an anodic plasma is studied. Dust density waves are excited when the cloud is larger than a wavelength, whereas a sloshing and stretching motion is found for smaller clouds. The wave dispersion shows similarities with waveguide modes.

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

    E-Print Network [OSTI]

    California at San Diego, University of

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

  19. Cloud Storage Standards Overview and Research Ideas Brainstorm

    E-Print Network [OSTI]

    Cloud Storage Standards Overview and Research Ideas Brainstorm Mark Carlson, SNIA TC and Sun Chair, SNIA Cloud Storage TWG CMU SDI Lecture ­ 12th November 2009 #12;Insert tutorial title in footer © 2009 Storage Networking Industry Association.All Rights Reserved. Abstract ! Cloud Storage is a new business

  20. A Survey of Mobile Cloud Computing Applications: Perspectives and Challenges

    E-Print Network [OSTI]

    Chen, Ing-Ray

    operating systems, configure computation environment, and develop software. The cloud provides a powerful from the marriage of powerful yet affordable mobile devices and cloud computing. In this paper we in the cloud. So users simply use the applications without concerning system configuration prob- lems

  1. 8, 42674308, 2008 3-D retrieval of cloud

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ACPD 8, 4267­4308, 2008 3-D retrieval of cloud particle profiles T. Zinner et al. Title Page.0 License. Atmospheric Chemistry and Physics Discussions Remote sensing of cloud sides of deep convection: towards a three-dimensional retrieval of cloud particle size profiles T. Zinner 1,2 , A. Marshak 1 , S

  2. CLOUD COVER REPORTING BIAS AT MAJOR AIRPORTS Richard Perez

    E-Print Network [OSTI]

    Perez, Richard R.

    CLOUD COVER REPORTING BIAS AT MAJOR AIRPORTS Richard Perez Joshua A. Bonaventura-Sparagna & Marek Kmiecik ASRC, SUNY, Albany, NY Ray George & David Renné NREL, Golden, CO ABSTRACT Cloud cover has been generated all or in part from cloud cover measurements [1,2]. This paper presents evidence

  3. Process-based Management of Cloud Computing Infrastructure

    E-Print Network [OSTI]

    Krause, Rolf

    Process-based Management of Cloud Computing Infrastructure Background Cloud Computing with minimal management effort. Examples of modern cloud computing solutions include (but are not limited to is an emerging computing capability that provides an abstraction between the computing resource and its

  4. Authorized Private Keyword Search over Encrypted Data in Cloud Computing

    E-Print Network [OSTI]

    Hou, Y. Thomas

    Authorized Private Keyword Search over Encrypted Data in Cloud Computing Ming Li, Shucheng Yu, Ning,ncao,wjlou}@ece.wpi.edu Dept. of CS, University of Arkansas at Little Rock, email: sxyu1@ualr.edu Abstract--In cloud computing In recent years, cloud computing is gaining much mo- mentum in the IT industry. Especially, we have seen

  5. Socially Optimal Pricing of Cloud Computing Resources Ishai Menache

    E-Print Network [OSTI]

    Shimkin, Nahum

    Socially Optimal Pricing of Cloud Computing Resources Ishai Menache Microsoft Research New England The cloud computing paradigm offers easily accessible com- puting resources of variable size and capabilities. We con- sider a cloud-computing facility that provides simultaneous service to a heterogeneous

  6. Special Publication 500-293 US Government Cloud Computing

    E-Print Network [OSTI]

    Special Publication 500-293 (Draft) US Government Cloud Computing Technology Roadmap Volume I Release 1.0 (Draft) High-Priority Requirements to Further USG Agency Cloud Computing Adoption Lee Badger Sokol, Jin Tong, Fred Whiteside and Dawn Leaf NIST Cloud Computing Program Information Technology

  7. Fuzzy Keyword Search over Encrypted Data in Cloud Computing

    E-Print Network [OSTI]

    Hou, Y. Thomas

    Fuzzy Keyword Search over Encrypted Data in Cloud Computing Jin Li, Qian Wang, Cong Wang, Ning Cao}@ece.wpi.edu Abstract--As Cloud Computing becomes prevalent, more and more sensitive information are being centralized in Cloud Computing as it greatly affects system usability, rendering user searching experiences very

  8. Special Publication 500-293 US Government Cloud Computing

    E-Print Network [OSTI]

    Special Publication 500-293 (Draft) US Government Cloud Computing Technology Roadmap Volume II and Dawn Leaf NIST Cloud Computing Program Information Technology Laboratory #12;This page left Publication 500-293 (Draft) US Government Cloud Computing Technology Roadmap Volume II Release 1.0 (Draft

  9. Coordination of Cloud Computing and Smart Power Grids

    E-Print Network [OSTI]

    Mohsenian-Rad, Hamed

    Coordination of Cloud Computing and Smart Power Grids Amir-Hamed Mohsenian-Rad and Alberto Leon.mohsenian.rad, alberto.leongarcia}@utoronto.ca Abstract--The emergence of cloud computing has established a trend towards increasing the load at locations where they are built. However, data centers and cloud computing also provide

  10. Controlling Data in the Cloud: Outsourcing Computation without Outsourcing Control

    E-Print Network [OSTI]

    Controlling Data in the Cloud: Outsourcing Computation without Outsourcing Control Richard Chow.fujitsu.com ABSTRACT Cloud computing is clearly one of today's most enticing technology areas due, at least in part, there are significant, persistent concerns about cloud computing that are impeding momentum and will eventually

  11. Adaptive Fault Tolerance in Real Time Cloud Computing Sheheryar Malik

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Adaptive Fault Tolerance in Real Time Cloud Computing Sheheryar Malik Research Team OASIS INRIA.huet@inria.fr Abstract -- With the increasing demand and benefits of cloud computing infrastructure, real time computing can be performed on cloud infrastructure. A real time system can take advantage of intensive computing

  12. Toward Secure and Dependable Storage Services in Cloud Computing

    E-Print Network [OSTI]

    Hou, Y. Thomas

    Toward Secure and Dependable Storage Services in Cloud Computing Cong Wang, Student Member, IEEE lightweight communication and computation cost. The auditing result not only ensures strong cloud storage, dependable distributed storage, error localization, data dynamics, cloud computing. Ç 1 INTRODUCTION SEVERAL

  13. Introduction to the IEEE Transactions on Cloud Computing

    E-Print Network [OSTI]

    Buyya, Rajkumar

    Introduction to the IEEE Transactions on Cloud Computing Rajkumar Buyya Welcome to the IEEE Transactions on Cloud Computing (TCC). It is my privilege and honor to serve as the inaugural Editor-in-Chief of TCC. I would like to thank the IEEE and the world-wide Cloud Computing community for giving me

  14. Efficient and Secure Data Storage Operations for Mobile Cloud Computing

    E-Print Network [OSTI]

    Efficient and Secure Data Storage Operations for Mobile Cloud Computing Zhibin Zhou and Dijiang Huang {zhibin.zhou,dijiang}@asu.edu Arizona State University Abstract--Cloud computing is a promising. With the development of wireless access technologies, cloud computing is expected to expand to mobile environments

  15. An Approach for Security Evaluation and Analysis in Cloud Computing

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    An Approach for Security Evaluation and Analysis in Cloud Computing T. Probst1,2 , E. Alata1,3 , M for security evaluation and analysis in cloud computing environments. The objective is to provide an automated way to evaluate the efficiency of security mechanisms aiming at protecting the cloud computing

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

    E-Print Network [OSTI]

    Lumsdaine, Andrew

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

  17. Summertime Arctic Clouds observed during SHEBA Paquita Zuidema

    E-Print Network [OSTI]

    Zuidema, Paquita

    understanding the underlying cloud processes (that impact the cloud optical depth). With the goal in mind consistently southerly and warm.The ice melt rate was directly measured to be 2.3-2.5 cm/day from gauges). The responsive surface melting during July suggests not only a high Sun angle,but also low cloud optical depths

  18. CLOUD DROPLET NUCLEATION AND ITS CONNECTION TO AEROSOL PROPERTIES

    E-Print Network [OSTI]

    of the uncertainty of the indirect effect arises from incomplete ability to describe changes in cloud properties. Keywords - Climate. aerosols. clouds, radiation INTRODUcnON In recent years awareness has increased of enhancement of scanering of radiation by aerosols in clear (cloud-free) air; a portion of the scattered

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

    E-Print Network [OSTI]

    Reiners, Peter W.

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

  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

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

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

    SciTech Connect (OSTI)

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

    2014-12-27T23:59:59.000Z

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

  2. Analysis of Cloud-resolving Simulations of a Tropical Mesoscale Convective System Observed during TWP-ICE: Vertical Fluxes and Draft Properties in Convective and Stratiform Regions

    SciTech Connect (OSTI)

    Mrowiec, Agnieszka A.; Rio, Catherine; Fridlind, Ann; Ackerman, Andrew; Del Genio, Anthony D.; Pauluis, Olivier; Varble, Adam; Fan, Jiwen

    2012-10-02T23:59:59.000Z

    We analyze three cloud-resolving model simulations of a strong convective event observed during the TWP-ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large-scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ~10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ~0.5 independent of species, and the ratio of downdraft to updraft mass flux is ~0.5-0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ~10% (graupel) to ~90% (cloud ice). These findings may lead to improved convection parameterizations.

  3. Separating real and apparent effects of cloud, humidity, and dynamics on aerosol optical thickness near cloud edges

    E-Print Network [OSTI]

    Li, Zhanqing

    have reported correlations between AOT and cloud cover, pointing to potential cloud contamination of Energy's Atmospheric Radiation Measurement Program. It was found that aerosol humidification effects can explain about one fourth of the correlation between the cloud cover and AOT. New particle genesis

  4. Argonne's Magellan Cloud Computing Research Project

    ScienceCinema (OSTI)

    Beckman, Pete

    2013-04-19T23:59:59.000Z

    Pete Beckman, head of Argonne's Leadership Computing Facility (ALCF), discusses the Department of Energy's new $32-million Magellan project, which designed to test how cloud computing can be used for scientific research. More information: http://www.anl.gov/Media_Center/News/2009/news091014a.html

  5. Workshop on Distributed Cloud Computing Dresden, Germany

    E-Print Network [OSTI]

    Schmid, Stefan

    DCC 2013 Workshop on Distributed Cloud Computing Dresden, Germany December 9-12, 2013 (Submission Pan Hui, HKUST, Hong Kong Wolfgang Kellerer, TU Munich, Germany Ruben Montero, Uni Complutense de Waterloo, Canada Marco Canini, T-Labs & TU Berlin, Germany Paolo Costa, MSR & Imperial College, UK Xiaoming

  6. Laser transmissionbackscattering through inhomogeneous cirrus clouds

    E-Print Network [OSTI]

    Takano, Yoshihide

    of the transmission and backscattering of high-energy laser beams. The 2D extinction-coefficient and mean effective of cirrus clouds by use of the Advanced Very High Resolution Radiometer on board National Oceanic and backscattering of high-energy laser beams in realistic atmospheres. The results of laser direct transmission

  7. The Magellan Final Report on Cloud Computing

    SciTech Connect (OSTI)

    ,; Coghlan, Susan; Yelick, Katherine

    2011-12-21T23:59:59.000Z

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

  8. The Pion Cloud: Insights into Hadron Structure

    E-Print Network [OSTI]

    A. W. Thomas

    2007-11-14T23:59:59.000Z

    Modern nuclear theory presents a fascinating study in contrasting approaches to the structure of hadrons and nuclei. Nowhere is this more apparent than in the treatment of the pion cloud. As this discussion really begins with Yukawa, it is entirely appropriate that this invited lecture at the Yukawa Institute in Kyoto should deal with the issue.

  9. Proof of Concept: Cloud Condensation Nucleus Counter

    E-Print Network [OSTI]

    Delene, David J.

    North Dakota project. The solid circle is the mean value, the horizontal line is the 50th percentile Price High Price #12;Research Applications · One commercially available cloud condensation nuclei (CCN) counter. · Available since 2002 · Sold over 100 Units, Mostly Labs · Price is Approximately $70

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

    SciTech Connect (OSTI)

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

    2009-03-05T23:59:59.000Z

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

  11. Properties of High-Redshift Lyman Alpha Clouds II. Statistical Properties of the Clouds

    E-Print Network [OSTI]

    William H. Press; George B. Rybicki

    1993-03-29T23:59:59.000Z

    Curve of growth analysis, applied to the Lyman series absorption ratios deduced in our previous paper, yields a measurement of the logarithmic slope of distribution of \\Lya\\ clouds in column density $N$. The observed exponential distribution of the clouds' equivalent widths $W$ is then shown to require a broad distribution of velocity parameters $b$, extending up to 80 km s$^{-1}$. We show how the exponential itself emerges in a natural way. An absolute normalization for the differential distribution of cloud numbers in $z$, $N$, and $b$ is obtained. By detailed analysis of absorption fluctuations along the line of sight we are able to put upper limits on the cloud-cloud correlation function $\\xi$ on several megaparsec length scales. We show that observed $b$ values, if thermal, are incompatible, in several different ways, with the hypothesis of equilibrium heating and ionization by a background UV flux. Either a significant component of $b$ is due to bulk motion (which we argue against on several grounds), or else the clouds are out of equilibrium, and hotter than is implied by their ionization state, a situation which could be indicative of recent adiabatic collapse.

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

    E-Print Network [OSTI]

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

    2015-01-28T23:59:59.000Z

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

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

    E-Print Network [OSTI]

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

    2014-01-01T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    Rudkevich, Aleksandr; Goldis, Evgeniy

    2012-12-02T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

    Wang, Minghuai; Penner, Joyce E.

    2010-06-21T23:59:59.000Z

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

  16. Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud

    E-Print Network [OSTI]

    T. Kudoh; S. Basu

    2003-06-23T23:59:59.000Z

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

  17. ARM - Field Campaign - Remote Cloud Sensing (RCS) Field Evaluation

    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- Polarization DiversityPolarization Radar govCampaignsRain Microphysics Study

  18. ARM - Field Campaign - Remote Cloud Sensing (RCS) Field Evaluation

    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- Polarization DiversityPolarization Radar govCampaignsRain Microphysics

  19. Dust Emission from the Perseus Molecular Cloud

    E-Print Network [OSTI]

    S. Schnee; J. Li; A. A. Goodman; A. I. Sargent

    2008-05-27T23:59:59.000Z

    Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular cloud. We show that the emission from transiently heated very small grains and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivities for colder grains. This variable emissivity can not be explained by temperature gradients along the line of sight or by noise in the emission maps, but is consistent with grain growth in the higher density and lower temperature regions. By accounting for the variations in the dust emissivity and VSG emission, we are able to map the temperature and column density of a nearby molecular cloud with better accuracy than has previously been possible.

  20. MAGIC: Marine ARM GPCI Investigation of Clouds

    SciTech Connect (OSTI)

    Lewis, ER; Wiscombe, WJ; Albrecht, BA; Bland, GL; Flagg, CN; Klein, SA; Kollias, P; Mace, G; Reynolds, RM; Schwartz, SE; Siebesma, AP; Teixeira, J; Wood, R; Zhang, M

    2012-10-03T23:59:59.000Z

    The second Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF2) will be deployed aboard the Horizon Lines cargo container ship merchant vessel (M/V) Spirit for MAGIC, the Marine ARM GPCI1 Investigation of Clouds. The Spirit will traverse the route between Los Angeles, California, and Honolulu, Hawaii, from October 2012 through September 2013 (except for a few months in the middle of this time period when the ship will be in dry dock). During this field campaign, AMF2 will observe and characterize the properties of clouds and precipitation, aerosols, and atmospheric radiation; standard meteorological and oceanographic variables; and atmospheric structure. There will also be two intensive observational periods (IOPs), one in January 2013 and one in July 2013, during which more detailed measurements of the atmospheric structure will be made.