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Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
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1

The Mixed-Phase Arctic Cloud Experiment  

Science Conference Proceedings (OSTI)

The Mixed-Phase Arctic Cloud Experiment (M-PACE) was conducted from 27 September through 22 October 2004 over the Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) on the North Slope of Alaska. The ...

J. Verlinde; J. Y. Harrington; V. T. Yannuzzi; A. Avramov; S. Greenberg; S. J. Richardson; C. P. Bahrmann; G. M. McFarquhar; G. Zhang; N. Johnson; M. R. Poellot; J. H. Mather; D. D. Turner; E. W. Eloranta; D. C. Tobin; R. Holz; B. D. Zak; M. D. Ivey; A. J. Prenni; P. J. DeMott; J. S. Daniel; G. L. Kok; K. Sassen; D. Spangenberg; P. Minnis; T. P. Tooman; M. Shupe; A. J. Heymsfield; R. Schofield

2007-02-01T23:59:59.000Z

2

Vertical Motions in Arctic Mixed-Phase Stratiform Clouds  

Science Conference Proceedings (OSTI)

The characteristics of Arctic mixed-phase stratiform clouds and their relation to vertical air motions are examined using ground-based observations during the Mixed-Phase Arctic Cloud Experiment (MPACE) in Barrow, Alaska, during fall 2004. The ...

Matthew D. Shupe; Pavlos Kollias; P. Ola G. Persson; Greg M. McFarquhar

2008-04-01T23:59:59.000Z

3

Towards a Characterization of Arctic Mixed-Phase Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

Towards a Characterization of Arctic Mixed-Phase Clouds Towards a Characterization of Arctic Mixed-Phase Clouds Shupe, Matthew CIRES/NOAA/ETL Kollias, Pavlos Brookhaven National Laboratory Category: Cloud Properties Mixed-phase clouds play a unique role in the Arctic, where the delicate balance of phases in these clouds can have a profound impact on the surface radiation balance and various cloud-atmosphere-radiation-surface feedback processes. A better understanding of these clouds is clearly important and has been a recent objective of the ARM program. To this end, multiple sensors including radar, lidar, and temperature soundings, have been utilized in an automated cloud type classification scheme for clouds observed at the North Slope of Alaska site. The performance of this new algorithm at identifying mixed-phase cloud conditions is compared with an

4

Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment  

SciTech Connect

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.

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

2005-03-18T23:59:59.000Z

5

Microphysical Properties of Single and Mixed-Phase Arctic Clouds...  

NLE Websites -- All DOE Office Websites (Extended Search)

Abstract A novel new approach to retrieve cloud microphysical properties from mixed-phase clouds is presented. This algorithm retrieves cloud optical depth, ice fraction, and...

6

TOWARDS A CHARACTERIZATION OF ARCTIC MIXED-PHASE CLOUDS CIRES/NOAA/ETL  

E-Print Network (OSTI)

, radar-based retrieval methods. On average, mixed-phase cloud ice particle mean diameters increase fromTOWARDS A CHARACTERIZATION OF ARCTIC MIXED-PHASE CLOUDS Shupe, M. CIRES/NOAA/ETL Kollias, P Laboratory P.O. Box, Upton, NY www.bnl.gov ABSTRACT Mixed-phase clouds play a unique role in the Arctic

7

Influence of parameterized ice habit on simulated mixed phase Arctic clouds  

E-Print Network (OSTI)

Influence of parameterized ice habit on simulated mixed phase Arctic clouds Alexander Avramov1 12 February 2010. [1] The phase partitioning of cloud mass between liquid and ice in mixed phase clouds and its dependence on ambient ice nuclei (IN) concentrations and ice habit parameterizations

8

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

SciTech Connect

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.

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

9

Ice properties of single-layer stratocumulus during the Mixed-Phase Arctic Cloud Experiment  

E-Print Network (OSTI)

Ice properties of single-layer stratocumulus during the Mixed-Phase Arctic Cloud Experiment: 2 opportunity to study poorly understood ice formation processes in mixed-phase stratocumulus. Using, were not significant sources of ice based on parameterizations from existing studies. After surveying

10

Intercomparison of Bulk Cloud Microphysics Schemes in Mesoscale Simulations of Springtime Arctic Mixed-Phase Stratiform Clouds  

Science Conference Proceedings (OSTI)

A persistent, weakly forced, horizontally extensive mixed-phase boundary layer cloud observed on 4–5 May 1998 during the Surface Heat Budget of the Arctic Ocean (SHEBA)/First International Satellite Cloud Climatology Project (ISCCP) Regional ...

H. Morrison; J. O. Pinto

2006-07-01T23:59:59.000Z

11

Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity to Microphysics Parameterizations  

Science Conference Proceedings (OSTI)

Single-layer mixed-phase stratiform (MPS) Arctic clouds, which formed under conditions of large surface heat flux combined with general subsidence during a subperiod of the Atmospheric Radiation Measurement (ARM) Program’s Mixed-Phase Arctic ...

Yali Luo; Kuan-Man Xu; Hugh Morrison; Greg McFarquhar

2008-04-01T23:59:59.000Z

12

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

SciTech Connect

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.

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

2005-03-18T23:59:59.000Z

13

Simulating mixed-phase Arctic stratus clouds: Sensitivity to ice initiationmechanisms  

SciTech Connect

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.

Sednev, I.; Menon, S.; McFarquhar, G.

2009-04-10T23:59:59.000Z

14

Simulating mixed-phase Arctic stratus clouds: sensitivity to ice initiation mechanisms  

SciTech Connect

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.

Sednev, Igor; Sednev, I.; Menon, S.; McFarquhar, G.

2008-02-18T23:59:59.000Z

15

A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes  

Science Conference Proceedings (OSTI)

Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)–Arctic Cloud Experiment (ACE)/Surface Heat Budget of the Arctic ...

Ann M. Fridlind; Bastiaan van Diedenhoven; Andrew S. Ackerman; Alexander Avramov; Agnieszka Mrowiec; Hugh Morrison; Paquita Zuidema; Matthew D. Shupe

2012-01-01T23:59:59.000Z

16

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

SciTech Connect

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.

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

17

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

SciTech Connect

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.

Turner, David D.

2003-06-01T23:59:59.000Z

18

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

NLE Websites -- All DOE Office Websites (Extended Search)

as well as aggregates to precipitation fluxes and radar reflectivity. Observations of icewater drop size distributions, cloud phase, etc., allow us to constrain model...

19

Mesoscale Modeling of Springtime Arctic Mixed-Phase Stratiform Clouds Using a New Two-Moment Bulk Microphysics Scheme  

Science Conference Proceedings (OSTI)

A new two-moment bulk microphysics scheme is implemented into the polar version of the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) to simulate arctic mixed-phase boundary layer stratiform clouds observed during ...

H. Morrison; J. O. Pinto

2005-10-01T23:59:59.000Z

20

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

SciTech Connect

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.

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

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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)

simulation that is in the ice-phase. Note that the y-axis isradiative properties of ice and mixed-phase clouds. Quart.include liquid-phase only, ice-phase only, and mixed-phase.

Klein, Stephen A.

2009-01-01T23:59:59.000Z

22

8, 1175511819, 2008 mixed-phase Arctic  

E-Print Network (OSTI)

, process of ice phase initiation due to freezing of25 supercooled water in both saturatedACPD 8, 11755Ā­11819, 2008 Simulating mixed-phase Arctic stratus clouds I. Sednev et al. Title Page.0 License. Atmospheric Chemistry and Physics Discussions Simulating mixed-phase Arctic stratus clouds

Paris-Sud XI, UniversitƩ de

23

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

SciTech Connect

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.

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

2007-06-01T23:59:59.000Z

24

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

SciTech Connect

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.

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

2005-03-18T23:59:59.000Z

25

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

SciTech Connect

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.

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

2008-02-29T23:59:59.000Z

26

The Sensitivity of Springtime Arctic Mixed-Phase Stratocumulus Clouds to Surface Layer and Cloud-Top Inversion Layer Moisture Sources  

Science Conference Proceedings (OSTI)

In this study a series of idealized large eddy simulations is used to understand the relative impact of cloud top and subcloud layer sources of moisture on the microphysical-radiative-dynamical feedbacks in an Arctic mixed-phase stratocumulus (...

Amy Solomon; Matthew D. Shupe; Ola Persson; Hugh Morrison; Takanobu Yamaguchi; Peter M. Caldwell; Gijs de Boer

27

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

SciTech Connect

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.

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

28

Arctic mixed-phase cloud properties derived from surface-based sensors at SHEBA  

E-Print Network (OSTI)

Mixed-phase clouds are an understudied component of global cloudiness and are thus poorly represented in models at all scales, which typically partition cloud phase as a function of temperature. The proper partitioning of cloud phase is particularly important considering the unique radiative properties of liquid droplets and ice particles, the impact of phase on precipitation processes, and the sensitivity of phase

M. D. Shupe; S. Y. Matrosov; T. Uttal

2006-01-01T23:59:59.000Z

29

Small Cloud Particle Shapes in Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

The shapes of cloud particles with maximum dimensions Dmax between 35 and 60 ?m in mixed-phase clouds were studied using high-resolution particle images collected by a cloud particle imager (CPI) during the Mixed-Phase Arctic Cloud Experiment (M-...

Greg M. McFarquhar; Junshik Um; Robert Jackson

2013-05-01T23:59:59.000Z

30

Representation of Arctic Mixed-Phase clouds and the Wegener-Bergeron-Findeisen Process in Climate Models: Perspectives from a Cloud-Resolving Study  

SciTech Connect

Two types of Arctic mixed-phase clouds observed during the ISDAC and M-PACE field campaigns are simulated using a 3-dimensional cloud-resolving model (CRM) with size-resolved cloud microphysics. The modeled cloud properties agree reasonably well with aircraft measurements and surface-based retrievals. Cloud properties such as the probability density function (PDF) of vertical velocity (w), cloud liquid and ice, the regime of ice growth at the expense of liquid water (i.e., Wegener-Bergeron-Findeisen (WBF) process), and the inherent relationships among cloud properties/processes in the mixed-phase layers are examined to gain insights for improving the representation of the mixed-phase processes in General Circulation Models (GCMs). We find that, the WBF process only occurs in about 50% of the mixed-phase regime with the vast majority occurring in the downdrafts. In updrafts both liquid and ice grow simultaneously. But in GCMs, it is not necessary to treat the WBF process at the subgrid scale. Our CRM results produce a w distribution well represented by a Gaussian normal function, validating, at least for arctic clouds, the subgrid treatment used in GCMs. Our CRM results also support the assumption frequently used in GCMs that mixed phase clouds maintain water vapor very near liquid saturation. A Gamma function with a fixed variance does not accurately represent the subgrid variability of cloud liquid. The PDFs of cloud liquid and cloud ice can be fitted with Gamma functions, and a normal function can be used for total water, but the variance should not be fixed. The relationship between the ice depositional growth rate and cloud ice strongly depends on the capacitance of ice particles. The assumption for the capacitance of ice particles (e.g., 1.0 for spheres) used in GCMs could lead to a large deviation in ice depositional growth. At large sales, the maximum overlap assumption looks appropriate.

Fan, Jiwen; Ghan, Steven J.; Ovchinnikov, Mikhail; Liu, Xiaohong; Rasch, Philip J.; Korolev, Alexei

2011-09-20T23:59:59.000Z

31

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

SciTech Connect

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.

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

2009-02-27T23:59:59.000Z

32

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

SciTech Connect

Cloud and aerosol data acquired by the National Research Council of Canada (NRC) Convair-580 aircraft in, above, and below single-layer arctic stratocumulus cloud during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in April 2008 were used to test three aerosol indirect effects hypothesized to act in mixed-phase clouds: the riming indirect effect, the glaciation indirect effect, and the cold second indirect effect. The data showed a correlation of R= 0.75 between liquid drop number concentration, Nliq, inside cloud and ambient aerosol number concentration NPCASP below cloud. This, combined with increasing liquid water content LWC with height above cloud base and the nearly constant profile of Nliq, suggested that liquid drops were nucleated from aerosol at cloud base. No strong evidence of a riming indirect effect was observed, but a strong correlation of R = 0.69 between ice crystal number concentration Ni and NPCASP above cloud was noted. Increases in ice nuclei (IN) concentration with NPCASP above cloud combined with the subadiabatic LWC profiles suggest possible mixing of IN from cloud top consistent with the glaciation indirect effect. The higher Nice and lower effective radius rel for the more polluted ISDAC cases compared to data collected in cleaner single-layer stratocumulus conditions during the Mixed-Phase Arctic Cloud Experiment is consistent with the operation of the cold second indirect effect. However, more data in a wider variety of meteorological and surface conditions, with greater variations in aerosol forcing, are required to identify the dominant aerosol forcing mechanisms in mixed-phase arctic clouds.

Jackson, Robert C.; McFarquhar, Greg; Korolev, Alexei; Earle, Michael; Liu, Peter S.; Lawson, R. P.; Brooks, Sarah D.; Wolde, Mengistu; Laskin, Alexander; Freer, Matthew

2012-08-14T23:59:59.000Z

33

Simulating mixed-phase Arctic stratus clouds: sensitivity to ice initiation mechanisms  

E-Print Network (OSTI)

M. : Role of a parameterized ice-phase mi- crophysics in anof contact nucleation in ice phase initiation in clouds, J.simulated, process of ice phase initiation due to freezing

Sednev, I.

2008-01-01T23:59:59.000Z

34

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

SciTech Connect

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.

Korolev, A; Shashkov, A; Barker, H

2012-03-06T23:59:59.000Z

35

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

SciTech Connect

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.

Korolev, A; Shashkov, A; Barker, H

2012-03-06T23:59:59.000Z

36

A Potential Role for Immersion Freezing in Arctic Mixed-Phase Stratus  

NLE Websites -- All DOE Office Websites (Extended Search)

Potential Role for Immersion Freezing in Arctic Mixed-Phase Stratus Potential Role for Immersion Freezing in Arctic Mixed-Phase Stratus Gijs de Boer, Edwin W. Eloranta, Tempei Hashino, and Gregory J. Tripoli The University of Wisconsin - Madison (1) Introduction Ice formation appears to a dominant factor controlling the lifecycle of Arctic mixed-phase clouds. To date, our understanding of ice formation in these long-lasting cloud structures does not explain the formation of observed ice amounts. Particularly puzzling are observa-

37

Arctic Mixed-Phase Cloud Properties Derived from Surface-Based Sensors at SHEBA MATTHEW D. SHUPE AND SERGEY Y. MATROSOV  

E-Print Network (OSTI)

, 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

Shupe, Matthew

38

Autumnal Mixed-Phase Cloudy Boundary Layers in the Arctic  

Science Conference Proceedings (OSTI)

Two mixed-phase cloudy boundary layer events observed over the Arctic ice pack in autumn are extensively analyzed. The local dynamic and thermodynamic structure of the boundary layers is determined from aircraft measurements including analysis of ...

James O. Pinto

1998-06-01T23:59:59.000Z

39

Radiative Influences on Glaciation Time-Scales of Mixed-Phase Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

Radiative Influences on Glaciation Time-Scales of Mixed-Phase Clouds Radiative Influences on Glaciation Time-Scales of Mixed-Phase Clouds Harrington, Jerry The Pennsylvania State University Category: Modeling Mixed-phase stratus clouds are dominant in the Arctic during much of the year. These clouds typically have liquid tops that precipitate ice. Time scales for the complete glaciation of such clouds (the Bergeron process) are typically computed using the classical mass growth equations for crystals and liquid drops. However, mixed phase arctic stratus have significant infrared cooling and solar heating (during the warm season) rates that can affect the growth of water drops and ice crystals, and therefore the strength of the Bergeron process. To examine the influence of radiative heating and cooling on the Bergeron process, we incorporate a

40

Mixed phase clouds, cloud electrification and remote sensing.  

SciTech Connect

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.

Chylek, P. (Petr); Borel, C. C. (Christoph C.); Klett, James

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Comparison of Aircraft Observations with Mixed-Phase Cloud Simulations  

Science Conference Proceedings (OSTI)

In order to provide guidance for the further improvement of a mixed-phase cloud scheme being developed for use in an NWP model, comparisons of dynamical, thermodynamical, and microphysical variables between in situ aircraft data and model data ...

Paul A. Vaillancourt; André Tremblay; Stewart G. Cober; George A. Isaac

2003-04-01T23:59:59.000Z

42

Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing:  

NLE Websites -- All DOE Office Websites (Extended Search)

Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: An Example from M-PACE Title Using Surface Remote Sensors to Derive Mixed-Phase Cloud Radiative Forcing: An Example from M-PACE Publication Type Journal Article Year of Publication 2011 Authors de Boer, Gijs, William D. Collins, Surabi Menon, and Charles N. Long Journal Atmospheric Chemistry and Physics Volume 11 Start Page 11937 Pagination 11937-11949 Abstract 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.

43

Simulations of Arctic mixed-phase clouds using a new aerosol-linked ice nuclei parameterization in a prognostic ice prediction scheme.  

E-Print Network (OSTI)

??Despite the nearly universally-accepted notion that the Arctic is one of the most important areas to fully understand in the face of a changing global… (more)

Carpenter, James Michael

2013-01-01T23:59:59.000Z

44

A Focus On Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

The phase composition and microphysical structure of clouds define the manner in which they modulate atmospheric radiation and contribute to the hydrologic cycle. Issues regarding cloud phase partitioning and transformation come to bear directly ...

Matthew D. Shupe; John S. Daniel; Gijs de Boer; Edwin W. Eloranta; Pavlos Kollias; Edward P. Luke; Charles N. Long; David D. Turner; Johannes Verlinde

2008-10-01T23:59:59.000Z

45

Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra  

NLE Websites -- All DOE Office Websites (Extended Search)

Mixed-Phase Cloud Retrievals Using Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra M. D. Shupe, S. Y. Matrosov, and T. L. Schneider National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado P. Kollias Rosentiel School of Marine Atmospheric Sciences University of Miami Miami, Florida Introduction The radar Doppler spectrum contains a wealth of information on cloud microphysical properties. Typically, radar-based cloud retrievals use only the zeroth or first moments of the Doppler spectrum - reflectivity and mean Doppler velocity - to derive quantities such as cloud water content and particle characteristic size (e.g., Liou and Sassen 1994; Matrosov et al. 2002). When using only the moments of the Doppler spectrum, important spectral information can be lost, particularly when the spectrum is

46

A Potential Role for Immersion Freezing in Arctic Mixed-Phase Stratus Gijs de Boer,Edwin W.Eloranta,Tempei Hashino,and Gregory J.Tripoli  

E-Print Network (OSTI)

to a dominant factor controlling the lifecycle of Arctic mixed-phase clouds. To date, our understanding of ice Stratus from M-PACE Mixed-Phase Layer Ice Precipitation "Bursts" Time (UT) Altitude(km) Lidar backscatter. - Additionally, Shupe illustrated that ice water content and liquid water content seem to vary in phase with each

Eloranta, Edwin W.

47

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

SciTech Connect

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.

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

2011-01-31T23:59:59.000Z

48

Limitations of the Wegener–Bergeron–Findeisen Mechanism in the Evolution of Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

Phase transformation and precipitation formation in mixed-phase clouds are usually associated with the Wegener–Bergeron–Findeisen (WBF) process in which ice crystals grow at the expense of liquid droplets. The evolution of mixed-phase clouds, ...

Alexei Korolev

2007-09-01T23:59:59.000Z

49

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

NLE Websites -- All DOE Office Websites (Extended Search)

6 6 Evaluation of Mixed-Phase Cloud Microphysics Parameterizations with the NCAR Single Column Climate Model (SCAM) and ARM Observations Second Quarter 2007 ARM Metric Report April 2007 Xiaohong Liu and Steven J. Ghan Pacific Northwest National Laboratory Richland, Washington Shaocheng Xie Lawrence Livermore National Laboratory Livermore, California Work supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research X. Lui, S.J. Ghan, and S. Xie, DOE/SC-ARM/P-07-006 Summary 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

50

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

SciTech Connect

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.

Liu, X; Ghan, SJ; Xie, S

2007-04-01T23:59:59.000Z

51

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

SciTech Connect

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.

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

2007-12-14T23:59:59.000Z

52

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

E-Print Network (OSTI)

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

Solomon, Amy

53

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

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.

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

2007-09-30T23:59:59.000Z

54

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

E-Print Network (OSTI)

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

Eloranta, Edwin W.

55

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

NLE Websites -- All DOE Office Websites (Extended Search)

when >0C and only ice crystals when < -40C, between 0 and -40C, clouds can be of ice, water, or mixed-phase composition (Rauber and Tokay 1991; Cober et al. 2001). Cloud...

56

The Vertical Profile of Liquid and Ice Water Content in Midlatitude Mixed-Phase Altocumulus Clouds  

Science Conference Proceedings (OSTI)

The microphysical properties of mixed-phase altocumulus clouds are investigated using in situ airborne measurements acquired during the ninth Cloud Layer Experiment (CLEX-9) over a midlatitude location. Approximately ? of the sampled profiles are ...

Lawrence D. Carey; Jianguo Niu; Ping Yang; J. Adam Kankiewicz; Vincent E. Larson; Thomas H. Vonder Haar

2008-09-01T23:59:59.000Z

57

Statistical Analysis of Aerosol Effects on Simulated Mixed-Phase Clouds and Precipitation in the Alps  

Science Conference Proceedings (OSTI)

Increasing the aerosol number in warm-phase clouds is thought to decrease the rain formation rate, whereas the physical processes taking place in mixed-phase clouds are more uncertain. Increasing number concentrations of soluble aerosols may ...

Elias M. Zubler; Ulrike Lohmann; Daniel Lüthi; Christoph Schär; Andreas Muhlbauer

2011-07-01T23:59:59.000Z

58

An Arctic Springtime Mixed-Phase Cloudy Boundary Layer Observed during SHEBA  

Science Conference Proceedings (OSTI)

The microphysical characteristics, radiative impact, and life cycle of a long-lived, surface-based mixed-layer, mixed-phase cloud with an average temperature of approximately ?20°C are presented and discussed. The cloud was observed during the ...

P. Zuidema; B. Baker; Y. Han; J. Intrieri; J. Key; P. Lawson; S. Matrosov; M. Shupe; R. Stone; T. Uttal

2005-01-01T23:59:59.000Z

59

An Analytic Scaling Law for the Depositional Growth of Snow in Thin Mixed-Phase Layer Clouds  

Science Conference Proceedings (OSTI)

In various practical problems, such as assessing the threat of aircraft icing or calculating radiative transfer, it is important to know whether mixed-phase clouds contain significant liquid water content. Some mixed-phase clouds remain ...

Vincent E. Larson; Adam J. Smith

2009-09-01T23:59:59.000Z

60

Parameterization of Ice Cloud Radiative Properties and Its Application to the Potential Climatic Importance of Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

It is often assumed, in modeling and radiation budget simulation, that clouds below the cirrus level are entirely in the liquid phase. There is substantive evidence from observations that low and middle clouds are often of mixed phase. Using a ...

Zhian Sun; Keith P. Shine

1995-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Effects of Aerosol Solubility and Regeneration on Mixed-Phase Orographic Clouds and Precipitation  

Science Conference Proceedings (OSTI)

A detailed bin aerosol-microphysics scheme has been implemented into the Weather Research and Forecast Model to investigate the effects of aerosol solubility and regeneration on mixed-phase orographic clouds and precipitation. Two-dimensional ...

Lulin Xue; Amit Teller; Roy Rasmussen; Istvan Geresdi; Zaitao Pan; Xiaodong Liu

2012-06-01T23:59:59.000Z

62

Improvements of a Mixed-Phase Cloud Scheme Using Aircraft Observations  

Science Conference Proceedings (OSTI)

To improve the quality of forecasts of mixed-phase clouds in winter storms, some aspects of a cloud scheme are examined in detail. Modifications to the basic formalism and specification of selected parameters of the cloud model are studied, and ...

André Tremblay; Paul A. Vaillancourt; Stewart G. Cober; Anna Glazer; George A. Isaac

2003-04-01T23:59:59.000Z

63

Radiative Processes in Upper Tropospheric Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

The diffusional mass evolution of hydrometeors in upper tropospheric clouds for various radiative conditions in the cloud and for varying ambient moisture Supply is simulated using a time dependent microphysical model. Radiation can play an ...

Douglas A. Wesley; Stephen K. Cox

1988-11-01T23:59:59.000Z

64

Observed Microphysical Structure ofObserved Microphysical Structure of MidMid--Level, MixedLevel, Mixed--Phase CloudsPhase Clouds  

E-Print Network (OSTI)

Level, Mixed--Phase CloudsPhase Clouds DOD Center for Geosciences/ Atmospheric Research Colorado State understood, but they cover ~ 22% of globe. Mixed-Phase Structure of Clouds Unknown. 30% are mixed-phase --- i.e. contain both ice and liquid. We need to know ice structure for weather and climate forecasts, e

65

Observed Microphysical Structure of Midlevel, Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

This paper analyzes airborne measurements of six midlevel clouds observed over the Great Plains of the United States in late 1999 and early 2000 during the fifth of the Complex Layered-Cloud Experiments (CLEX-5). Data show that these innocuous-...

Robert P. Fleishauer; Vincent E. Larson; Thomas H. Vonder Haar

2002-06-01T23:59:59.000Z

66

Relative Humidity in Liquid, Mixed-Phase, and Ice Clouds  

Science Conference Proceedings (OSTI)

The results of in situ observations of the relative humidity in liquid, mixed, and ice clouds typically stratiform in nature and associated with mesoscale frontal systems at temperatures ?45°C < Ta < ?5°C are presented. The data were collected ...

Alexei Korolev; George A. Isaac

2006-11-01T23:59:59.000Z

67

Aerosol Influence on Mixed-Phase Clouds in CAM-Oslo  

Science Conference Proceedings (OSTI)

A new treatment of mixed-phase cloud microphysics has been implemented in the general circulation model, Community Atmosphere Model (CAM)-Oslo, which combines the NCAR CAM2.0.1 and a detailed aerosol module. The new treatment takes into account ...

Trude Storelvmo; Jón Egill Kristjįnsson; Ulrike Lohmann

2008-10-01T23:59:59.000Z

68

Parameterization of ice cloud radiative properties and its application to the potential climatic importance of mixed-phase clouds  

SciTech Connect

It is often assumed, in modeling and radiation budget simulation, that clouds below the cirrus level are entirely in the liquid phase. There is substantive evidence from observations that low and middle clouds are often of mixed phase. Using a light-scattering program for hexagonal crystals, the authors update a parameterization of the radiative properties of ice clouds from an earlier study and use the new parameterization to investigate the role of mixed-phase clouds in three areas: (i) the interpretation of ISCCP optical depth, (ii) the simulation of the earth radiation budget, and (iii) the sensitivity of a simple radiative-convective model to an increase in CO{sub 2}. In all cases, mixed-phase clouds are shown to have the potential to significantly modify the results obtained using liquid phase clouds. A precise quantification is not yet possible as the dependence of the fraction of ice and liquid water is mixed-phase clouds on atmospheric properties, and the way in which the ice and liquid water are mixed, are not known with sufficient detail. 43 refs., 17 figs., 2 tabs.

Sun, Z.; Shine, K.P. [Univ. of Reading (United Kingdom)] [Univ. of Reading (United Kingdom)

1995-07-01T23:59:59.000Z

69

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)

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

Zuidema, Paquita

70

Effects of ice number concentration on dynamics of a shallow mixed-phase stratiform cloud  

SciTech Connect

Previous modeling studies have shown a high sensitivity of simulated properties of mixed-phase clouds to ice number concentration, Ni, with many models losing their ability to maintain the liquid phase as Ni increases. Although models differ widely at what Ni the mixed-phase cloud becomes unstable, the transition from a mixed-phase to an ice only cloud in many cases occurs over a narrow range of ice concentration. To gain better understanding of this non-linear model behavior, in this study, we analyze simulations of a mixed-phase stratiform Artic cloud observed on 26 April 2008 during recent Indirect and Semi-Direct Aerosol Campaign (ISDAC). The BASE simulation, in which Ni is constrained to match the measured value, produces a long-lived cloud in a quasi steady state similar to that observed. The simulation without the ice (NO_ICE) produces a comparable but slightly thicker cloud because more moisture is kept in the mixed layer due to lack of precipitation. When Ni is quadrupled relative to BASE (HI_ICE), the cloud starts loosing liquid water almost immediately and the liquid water path is reduced by half in less than two hours. The changes in liquid water are accompanied by corresponding reduction in the radiative cooling of the layer and a slow down in the vertical mixing, confirming the important role of interactions among microphysics, radiation and dynamics in this type of clouds. Deviations of BASE and HI_ICE from NO_ICE are used to explore the linearity of the model response to variation in Ni. It is shown that at early stages, changes in liquid and ice water as well as in radiative cooling/heating rates are proportional to the Ni change, while changes in the vertical buoyancy flux are qualitatively different in HI_ICE compared to BASE. Thus, while the positive feedback between the liquid water path and radiative cooling of the cloud layer is essential for glaciation of the cloud at higher Ni, the non-linear (with respect to Ni) reduction in positive buoyancy flux within and below the liquid cloud layer emerges as the process that influences the initial response of the mixed layer dynamics to the appearance of ice and subsequently determines the sustainability of liquid water in the cloud in this case.

Ovchinnikov, Mikhail; Korolev, Alexei; Fan, Jiwen

2011-09-17T23:59:59.000Z

71

Sensitivity Studies of the Importance of Dust Ice Nuclei for the Indirect Aerosol Effect on Stratiform Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

New parameterizations of contact freezing and immersion freezing in stratiform mixed-phase clouds (with temperatures between 0° and ?35°C) for black carbon and mineral dust assumed to be composed of either kaolinite (simulation KAO) or ...

U. Lohmann; K. Diehl

2006-03-01T23:59:59.000Z

72

Estimation of Mixed-Phase Cloud Optical Depth and Position Using In Situ Radiation and Cloud Microphysical Measurements Obtained from a Tethered-Balloon Platform  

Science Conference Proceedings (OSTI)

Microphysical and radiative measurements in boundary layer mixed-phase clouds (MPCs), consisting of ice crystals and liquid droplets, have been analyzed. These cloud measurements were collected during a May–June 2008 tethered-balloon campaign in ...

M. Sikand; J. Koskulics; K. Stamnes; B. Hamre; J. J. Stamnes; R. P. Lawson

2013-01-01T23:59:59.000Z

73

Overview of Arctic Cloud and Radiation Characteristics  

Science Conference Proceedings (OSTI)

To provide a background for ARM's activities at the North Slope of Alaska/Adjacent Arctic Ocean sites, an overview is given of our current state of knowledge of Arctic cloud and radiation properties and processes. The authors describe the Arctic ...

Judith A. Curry; Julie L. Schramm; William B. Rossow; David Randall

1996-08-01T23:59:59.000Z

74

In Situ Aircraft Measurements of the Vertical Distribution of Liquid and Ice Water Content in Midlatitude Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

The vertical distribution of liquid and ice water content and their partitioning is studied using 34 cases of in situ measured microphysical properties in midlatitude mixed-phase clouds, with liquid water path ranging from near zero to ~248 g m?2, ...

Yoo-Jeong Noh; Curtis J. Seaman; Thomas H. Vonder Haar; Guosheng Liu

2013-01-01T23:59:59.000Z

75

A Scheme for Calculation of the Liquid Fraction in Mixed-Phase Stratiform Clouds in Large-Scale Models  

Science Conference Proceedings (OSTI)

A scheme for calculation of the liquid fraction fl in mixed-phase stratiform clouds has been developed for use in large-scale models. An advantage of the scheme, compared to the interpolation in temperature that is typically used, is that it ...

Leon D. Rotstayn; Brian F. Ryan; Jack J. Katzfey

2000-04-01T23:59:59.000Z

76

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

Science Conference Proceedings (OSTI)

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.

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

2012-09-28T23:59:59.000Z

77

Clouds at Arctic Atmospheric Observatories. Part II: Thermodynamic Phase Characteristics  

Science Conference Proceedings (OSTI)

Cloud phase defines many cloud properties and determines the ways in which clouds interact with other aspects of the climate system. The occurrence fraction and characteristics of clouds distinguished by their phase are examined at three Arctic ...

Matthew D. Shupe

2011-03-01T23:59:59.000Z

78

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

E-Print Network (OSTI)

ice nucleation parameterization slightly improves the model performance for low-level mixed-phase ice loss by enhancing ice-albedo feedbacks [Kay et al., 2008]. Arctic clouds are often mixed-phase (i-Direct Aerosol Campaign (ISDAC) and Mixed-Phase Arctic Cloud Experiment (M-PACE), which were conducted at its

79

Sensitivity Studies of Aerosol–Cloud Interactions in Mixed-Phase Orographic Precipitation  

Science Conference Proceedings (OSTI)

Anthropogenic aerosols serve as a source of both cloud condensation nuclei (CCN) and ice nuclei (IN) and affect microphysical properties of clouds. Increasing aerosol number concentration is assumed to retard the cloud droplet coalescence and the ...

Andreas Muhlbauer; Ulrike Lohmann

2009-09-01T23:59:59.000Z

80

Minimalist Model of Ice Microphysics in Mixed-phase Stratiform Clouds  

SciTech Connect

The question of whether persistent ice crystal precipitation from super cooled layer clouds can be explained by time-dependent, stochastic ice nucleation is explored using an approximate, analytical model, and a large-eddy simulation (LES) cloud model. The updraft velocity in the cloud defines an accumulation zone, where small ice particles cannot fall out until they are large enough, which will increase the residence time of ice particles in the cloud. Ice particles reach a quasi-steady state between growth by vapor deposition and fall speed at cloud base. The analytical model predicts that ice water content (wi) has a 2.5 power law relationship with ice number concentration ni. wi and ni from a LES cloud model with stochastic ice nucleation also confirm the 2.5 power law relationship. The prefactor of the power law is proportional to the ice nucleation rate, and therefore provides a quantitative link to observations of ice microphysical properties.

Yang, F.; Ovchinnikov, Mikhail; Shaw, Raymond A.

2013-07-28T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Dynamical and Microphysical Characteristics of Arctic Clouds during BASE  

Science Conference Proceedings (OSTI)

In this study, observations from aircraft, Doppler radar, and LANDSAT are used to better understand dynamical and microphysical characteristics of low-level Arctic clouds for climate change studies. Observations during the Beaufort and Arctic ...

I. Gultepe; G. Isaac; D. Hudak; R. Nissen; J. W. Strapp

2000-04-01T23:59:59.000Z

82

A Modeling Case Study of Mixed-Phase Clouds over the Southern Ocean and Tasmania  

Science Conference Proceedings (OSTI)

The cloud structure associated with two frontal passages over the Southern Ocean and Tasmania is investigated. The first event, during August 2006, is characterized by large quantities of supercooled liquid water and little ice. The second case, ...

Anthony E. Morrison; Steven T. Siems; Michael J. Manton; Alex Nazarov

2010-03-01T23:59:59.000Z

83

AMSU-B Observations of Mixed-Phase Clouds over Land  

Science Conference Proceedings (OSTI)

Measurements from passive microwave satellite instruments such as the Advanced Microwave Sounding Unit B (AMSU-B) are sensitive to both liquid and ice cloud particles. Radiative transfer modeling is exploited to simulate the response of the AMSU-...

M. N. Deeter; J. Vivekanandan

2005-01-01T23:59:59.000Z

84

A Dual-Wavelength Radar Method for Ice-Water Characterization in Mixed-Phase Clouds  

Science Conference Proceedings (OSTI)

A dual-wavelength method to differentiate supercooled water from ice and to measure mass content in each phase in cold stratiform clouds is proposed and discussed. The differential attenuation Ad, whose direct measurement is available with dual-...

Marielle Gosset; Henri Sauvageot

1992-10-01T23:59:59.000Z

85

Nighttime Cloud Detection Over the Arctic Using AVHRR Data  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Detection Over the Arctic Cloud Detection Over the Arctic Using AVHRR Data D. A. Spangenberg, D. R. Doelling, and V. Chakrapani Analytical Services & Materials, Inc. Hampton, Virginia P. Minnis National Aeronautics and Space Administration Hampton, Virginia T. Uttal National Oceanic and Atmospheric Administration Boulder, Colorado Introduction Clouds play an important role in the Arctic energy budget. The magnitude and significance of the radiative impact of polar clouds, however, are not well known. Polar nocturnal clouds are often warmer or at the same temperature as the background snow surface, complicating cloud detection. Also, these clouds tend to be thin, with lower emittances than clouds occurring during the summer. Using only the infrared (IR) channels of satellite data to characterize cloud amount and distribution in the Arctic is

86

Black carbon enrichment in atmospheric ice particle residuals observed in lower tropospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice crystals was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 ?m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 27% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC containing particles preferentially act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Daniel J.; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

87

Black carbon enrichment in atmospheric ice particle residuals observed in lower trophospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice particles was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 14% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC may act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Dan; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

88

Observed Relationships between Arctic Longwave Cloud Forcing and Cloud Parameters Using a Neural Network  

Science Conference Proceedings (OSTI)

A neural network technique is used to quantify relationships involved in cloud–radiation feedbacks based on observations from the Surface Heat Budget of the Arctic (SHEBA) project. Sensitivities of longwave cloud forcing (CFL) to cloud parameters ...

Yonghua Chen; Filipe Aires; Jennifer A. Francis; James R. Miller

2006-08-01T23:59:59.000Z

89

Deployment of a Tethered-Balloon System for Microphysics and Radiative Measurements in Mixed-Phase Clouds at Ny-Ålesund and South Pole  

Science Conference Proceedings (OSTI)

A tethered-balloon system capable of making microphysical and radiative measurements in clouds is described and examples of measurements in boundary layer stratus clouds in the Arctic and at the South Pole are presented. A 43-m3 helium-filled ...

R. Paul Lawson; Knut Stamnes; Jakob Stamnes; Pat Zmarzly; Jeff Koskuliks; Chris Roden; Qixu Mo; Michael Carrithers; Geoffrey L. Bland

2011-05-01T23:59:59.000Z

90

Relationships between Arctic Sea Ice and Clouds during Autumn  

Science Conference Proceedings (OSTI)

The connection between sea ice variability and cloud cover over the Arctic seas during autumn is investigated by analyzing the 40-yr ECMWF Re-Analysis (ERA-40) products and the Television and Infrared Observation Satellite (TIROS) Operational ...

Axel J. Schweiger; Ron W. Lindsay; Steve Vavrus; Jennifer A. Francis

2008-09-01T23:59:59.000Z

91

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

E-Print Network (OSTI)

M. : Role of a parameterized ice-phase micro- physics in anconcentration (N i ) for ice phase in experiments with icei L ?1 Table 8. Composite ice phase effective radius (R ei )

Sednev, I.

2009-01-01T23:59:59.000Z

92

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

E-Print Network (OSTI)

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

Sednev, I.

2009-01-01T23:59:59.000Z

93

Mixed-Phase Arctic Cloud Experiment (M-PACE): the Field Campaign  

DOE Data Explorer (OSTI)

This case study presents data from 27 Sep 2004 to 22 Oct 2004 and covers a region from 65N to 75N latitude and from 160W to 145W longitude.

94

Cirriform Rotor Cloud Observed on a Canadian Arctic Ice Cap  

Science Conference Proceedings (OSTI)

A thin rotor cloud was observed on the lee side of Penny Ice Cap in the Canadian Arctic on 21 April 1996. The cloud consisted of thin cirriform layers, so that its motion was clearly observed. By means of time-lapse camera photography, the ...

Hisashi Ozawa; Kumiko Goto-Azuma; Koyuru Iwanami; Roy M. Koerner

1998-06-01T23:59:59.000Z

95

On the Relationship between Thermodynamic Structure and Cloud Top, and Its Climate Significance in the Arctic  

Science Conference Proceedings (OSTI)

Cloud and thermodynamic characteristics from three Arctic observation sites are investigated to understand the collocation between low-level clouds and temperature inversions. A regime where cloud top was 100–200 m above the inversion base [cloud ...

Joseph Sedlar; Matthew D. Shupe; Michael Tjernström

2012-04-01T23:59:59.000Z

96

Arctic Ocean Radiative Fluxes and Cloud Forcing Estimated from the ISCCP C2 Cloud Dataset, 1983?1990  

Science Conference Proceedings (OSTI)

Radiative fluxes and cloud forcings for the ocean areas of the Arctic are computed from the monthly cloud product of the International Satellite Cloud Climatology Project (ISCCP) for 1983?90. Spatially averaged short-wave fluxes compare well with ...

Axel J. Schweiger; Jeffrey R. Key

1994-08-01T23:59:59.000Z

97

Influence of Humidified Aerosol on Lidar Depolarization Measurements below Ice-Precipitating Arctic Stratus  

Science Conference Proceedings (OSTI)

Lidar measurements obtained during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment under a mixed-phase stratus cloud that was lightly precipitating ice show a range of surprisingly low depolarization ratios (4%–23%), despite an ...

Bastiaan van Diedenhoven; Ann M. Fridlind; Andrew S. Ackerman

2011-10-01T23:59:59.000Z

98

Major Cloud Plumes in the Arctic and Their Relation to Fronts and Ice Movement  

Science Conference Proceedings (OSTI)

A study of the movement of orographic cloud plumes from one island to another in the Svalbard-Novaya Zemlya region of the Barents Sea revealed a close association with similar movements of arctic fronts. Strong northerly winds behind arctic ...

Robert W. Fett

1992-06-01T23:59:59.000Z

99

The Influence of Changes in Cloud Cover on Recent Surface Temperature Trends in the Arctic  

Science Conference Proceedings (OSTI)

A method is presented to assess the influence of changes in Arctic cloud cover on the surface temperature trend, allowing for a more robust diagnosis of causes for surface warming or cooling. Seasonal trends in satellite-derived Arctic surface ...

Yinghui Liu; Jeffrey R. Key; Xuanji Wang

2008-02-01T23:59:59.000Z

100

Simulation of Effects of Atmospheric Aerosols on Deep Turbulent Convective Clouds Using a Spectral Microphysics Mixed-Phase Cumulus Cloud Model. Part II: Sensitivity Study  

Science Conference Proceedings (OSTI)

Effects of different size distributions of cloud condensational nuclei (CCN) on the evolution of deep convective clouds under dry unstable continental thermodynamic conditions are investigated using the spectral microphysics Hebrew University ...

A. Khain; A. Pokrovsky

2004-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Simulation of Effects of Atmospheric Aerosols on Deep Turbulent Convective Clouds Using a Spectral Microphysics Mixed-Phase Cumulus Cloud Model. Part I: Model Description and Possible Applications  

Science Conference Proceedings (OSTI)

An updated version of the spectral (bin) microphysics cloud model developed at the Hebrew University of Jerusalem [the Hebrew University Cloud Model (HUCM)] is described. The model microphysics is based on the solution of the equation system for ...

A. Khain; A. Pokrovsky; M. Pinsky; A. Seifert; V. Phillips

2004-12-01T23:59:59.000Z

102

Observational and Theoretical Studies of Solar Radiation in Arctic Stratus Clouds  

Science Conference Proceedings (OSTI)

A series of clouds-radiation experiments was carried out in June 1980 in Arctic stratus clouds occurring over the Beaufort Sea using the NCAR Electra aircraft. This paper is an analysis of the hemispheric radiation fields obtained with Eppley ...

G. F. Herman; J. A. Curry

1984-01-01T23:59:59.000Z

103

Clouds at Arctic Atmospheric Observatories. Part I: Occurrence and Macrophysical Properties  

Science Conference Proceedings (OSTI)

Cloud observations over the past decade from six Arctic atmospheric observatories are investigated to derive estimates of cloud occurrence fraction, vertical distribution, persistence in time, diurnal cycle, and boundary statistics. Each ...

Matthew D. Shupe; Von P. Walden; Edwin Eloranta; Taneil Uttal; James R. Campbell; Sandra M. Starkweather; Masataka Shiobara

2011-03-01T23:59:59.000Z

104

Statistical Analysis of Forecasting Models across the North Slope of Alaska during the Mixed-Phase Arctic Clouds Experiment  

Science Conference Proceedings (OSTI)

The National Centers for Environmental Prediction’s (NCEP) Eta Model, the models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Aeronautics and Space Administration’s (NASA) Global Modeling and Assimilation ...

Victor T. Yannuzzi; Eugene E. Clothiaux; Jerry Y. Harrington; Johannes Verlinde

2009-12-01T23:59:59.000Z

105

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

SciTech Connect

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.

J. O. Pinto, A.H. Lynch

2005-12-14T23:59:59.000Z

106

Arctic Cloud Microphysics Retrievals from Surface-Based Remote Sensors at SHEBA  

Science Conference Proceedings (OSTI)

An operational suite of ground-based, remote sensing retrievals for producing cloud microphysical properties is described, assessed, and applied to 1 yr of observations in the Arctic. All measurements were made in support of the Surface Heat ...

Matthew D. Shupe; Taneil Uttal; Sergey Y. Matrosov

2005-10-01T23:59:59.000Z

107

Turbulence Structure of Arctic Stratus Clouds Derived from Measurements and Calculations  

Science Conference Proceedings (OSTI)

Results are presented from a detailed case study of an Arctic stratus cloud over the Fram Strait that is based on aircraft measurements and model calculations. The measurements have been performed during MIZEX 1984 (Marginal Ice Zone Experiment) ...

Jörg E. Finger; Peter Wendling

1990-06-01T23:59:59.000Z

108

Remote Sensing of Surface and Cloud Properties in the Arctic from AVHRR Measurements  

Science Conference Proceedings (OSTI)

Algorithms to retrieve cloud optical depth and effective radius in the Arctic using Advanced Very High Resolution Radiometer (AVHRR) data are developed, using a comprehensive radiative transfer model in which the atmosphere is coupled to the ...

W. Han; K. Stamnes; Dan Lubin

1999-07-01T23:59:59.000Z

109

Sensitivity of CAM5-Simulated Arctic Clouds and Radiation to Ice Nucleation Parameterization  

Science Conference Proceedings (OSTI)

Sensitivity of Arctic clouds and radiation in the Community Atmospheric Model, version 5, to the ice nucleation process is examined by testing a new physically based ice nucleation scheme that links the variation of ice nuclei (IN) number ...

Shaocheng Xie; Xiaohong Liu; Chuanfeng Zhao; Yuying Zhang

2013-08-01T23:59:59.000Z

110

ARM - Publications: Science Team Meeting Documents: An Arctic Springtime  

NLE Websites -- All DOE Office Websites (Extended Search)

An Arctic Springtime Mixed-Phase Cloudy Boundary Layer observed during An Arctic Springtime Mixed-Phase Cloudy Boundary Layer observed during SHEBA Zuidema, Paquita RSMAS/MPO University of Miami Han, Yong NASA Goddard Space Flight Center Intrieri, Janet NOAA/Environmental Technology Laboratory Key, Jeffrey Boston University Lawson, Paul SPEC Inc. Matrosov, Sergey NOAA/Environmental Technology Laboratory Shupe, Matthew CIRES/NOAA/ETL Uttal, Taneil NOAA/Environmental Technology Laboratory The microphysical characteristics, radiative impact, and lifecycle of a long-lived, surface-based mixed-layer, mixed-phase cloud with an average temperature of approximately -20 C are presented and discussed. The cloud was observed during the Surface Heat Budget of the Arctic experiment from May 1 through May 10, 1998. Vertically-resolved properties of the liquid

111

A Critical Examination of Satellite Cloud Retrieval from AVHRR in the Arctic Using SHEBA Data  

Science Conference Proceedings (OSTI)

This study examines the validity and limitations associated with retrieval of cloud optical depth ? and effective droplet size re in the Arctic from Advanced Very High Resolution Radiometer (AVHRR) channels 2 (0.725–1.10 ?m), 3 (3.55–3.93 ?m), ...

Xiaozhen Xiong; Dan Lubin; Wei Li; Knut Stamnes

2002-12-01T23:59:59.000Z

112

Distribution and Validation of Cloud Cover Derived from AVHRR Data Over the Arctic Ocean During the SHEBA Year  

NLE Websites -- All DOE Office Websites (Extended Search)

and Validation of Cloud Cover and Validation of Cloud Cover Derived from AVHRR Data Over the Arctic Ocean During the SHEBA Year P. Minnis National Aeronautics and Space Administration Langley Research Center Hampton, Virginia D. A. Spangenberg and V. Chakrapani Analytical Services and Materials, Inc. Hampton, Virginia Introduction Determination of cloud radiation interactions over large areas of the Arctic is possible only with the use of data from polar orbiting satellites. Cloud detection using satellite data is difficult in the Arctic due to the minimal contrast between clouds and the underlying snow surface in visible and infrared wavelengths. Polar clouds are frequently warmer or at the same brightness temperature as the background surface, complicating cloud detection. The brightness temperature differences between the

113

Indirect and Semi-Direct Aerosol Campaign: The Impact of Arctic Aerosols on Clouds  

SciTech Connect

A comprehensive dataset of microphysical and radiative properties of aerosols and clouds in the arctic boundary layer in the vicinity of Barrow, Alaska was collected in April 2008 during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) sponsored by the Department of Energy Atmospheric Radiation Measurement (ARM) and Atmospheric Science Programs. The primary aim of ISDAC was to examine indirect effects of aerosols on clouds that contain both liquid and ice water. The experiment utilized the ARM permanent observational facilities at the North Slope of Alaska (NSA) in Barrow. These include a cloud radar, a polarized micropulse lidar, and an atmospheric emitted radiance interferometer as well as instruments specially deployed for ISDAC measuring aerosol, ice fog, precipitation and spectral shortwave radiation. The National Research Council of Canada Convair-580 flew 27 sorties during ISDAC, collecting data using an unprecedented 42 cloud and aerosol instruments for more than 100 hours on 12 different days. Data were obtained above, below and within single-layer stratus on 8 April and 26 April 2008. These data enable a process-oriented understanding of how aerosols affect the microphysical and radiative properties of arctic clouds influenced by different surface conditions. Observations acquired on a heavily polluted day, 19 April 2008, are enhancing this understanding. Data acquired in cirrus on transit flights between Fairbanks and Barrow are improving our understanding of the performance of cloud probes in ice. Ultimately the ISDAC data will be used to improve the representation of cloud and aerosol processes in models covering a variety of spatial and temporal scales, and to determine the extent to which long-term surface-based measurements can provide retrievals of aerosols, clouds, precipitation and radiative heating in the Arctic.

McFarquhar, Greg; Ghan, Steven J.; Verlinde, J.; Korolev, Alexei; Strapp, J. Walter; Schmid, Beat; Tomlinson, Jason M.; Wolde, Mengistu; Brooks, Sarah D.; Cziczo, Daniel J.; Dubey, Manvendra K.; Fan, Jiwen; Flynn, Connor J.; Gultepe, Ismail; Hubbe, John M.; Gilles, Mary K.; Laskin, Alexander; Lawson, Paul; Leaitch, W. R.; Liu, Peter S.; Liu, Xiaohong; Lubin, Dan; Mazzoleni, Claudio; Macdonald, A. M.; Moffet, Ryan C.; Morrison, H.; Ovchinnikov, Mikhail; Shupe, Matthew D.; Turner, David D.; Xie, Shaocheng; Zelenyuk, Alla; Bae, Kenny; Freer, Matthew; Glen, Andrew

2011-02-01T23:59:59.000Z

114

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

SciTech Connect

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.

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

115

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

SciTech Connect

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.

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

116

Arctic Cloud Characteristics as Derived from MODIS, CALIPSO, and CloudSat  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectroradiometer (MODIS), Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP), and CloudSat Cloud Profiling Radar (CPR) set of sensors, all in the Afternoon Constellation (A-Train), has been regarded as among ...

Mark Aaron Chan; Josefino C. Comiso

2013-05-01T23:59:59.000Z

117

ARM - Field Campaign - FIRE-Arctic Cloud Experiment/SHEBA  

NLE Websites -- All DOE Office Websites (Extended Search)

g-meter, the Pilewskie Solar Spectral Flux Radiometer (SSFR), the NASA-GoddardU. of Wash. Spectral Scanning Radiometer, and the SPEC Inc. Cloud Particle Imager. This was the...

118

The 1990 Valentine's Day Arctic Outbreak. Part I: Mesoscale and Microscale Structure and Evolution of a Colorado Front Range Shallow Upslope Cloud  

Science Conference Proceedings (OSTI)

The mesoscale and microscale structure and evolution of a shallow, upslope cloud is described using observations obtained during the Winter Icing and Storms Project (WISP) and model stimulations. The upslope cloud formed within a shallow arctic ...

Roy M. Rasmussen; Ben C. Bernstein; Masataka Murakami; Greg Stossmeister; Jon Reisner; Boba Stankov

1995-07-01T23:59:59.000Z

119

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

Science Conference Proceedings (OSTI)

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.

Dana E. Veron

2012-04-09T23:59:59.000Z

120

Mixed-Phase Microphysics and Cloud Electrification  

Science Conference Proceedings (OSTI)

A number of experimental studies have shown that sublimating ice acquires negative charge and ice undergoing vapor deposition acquires positive charge. Microphysical calculations are performed to determine the diffusional state (i.e., sublimation ...

E. R. Williams; R. Zhang; J. Rydock

1991-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Short-Term Arctic Cloud Statistics at NSA from the Infrared Cloud...  

NLE Websites -- All DOE Office Websites (Extended Search)

J. A. Shaw and B. Thurairajah Department of Electrical and Computer Engineering Montana State University Bozeman, Montana Introduction The infrared cloud imager (ICI) is a...

122

ARM - Measurement - Cloud phase  

NLE Websites -- All DOE Office Websites (Extended Search)

property that captures the state o f the hydrometeors within a cloud (liquid, ice, or mixed-phase). This is distinct from cloud type that involves property descriptors...

123

ARM - PI Product - Cloud-Scale Vertical Velocity and Turbulent Dissipation  

NLE Websites -- All DOE Office Websites (Extended Search)

ProductsCloud-Scale Vertical Velocity and Turbulent ProductsCloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Site(s) NSA General Description 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

124

Arctic Stratus Cloud Properties and Radiative Forcing Derived from Ground-Based Data Collected at Barrow, Alaska  

Science Conference Proceedings (OSTI)

A record of single-layer and overcast low-level Arctic stratus cloud properties has been generated using data collected from May to September 2000 at the Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) (71.3°N, 156.6°W) site ...

Xiquan Dong; Gerald G. Mace

2003-02-01T23:59:59.000Z

125

Polar Stratospheric Cloud Observations in the 2006/07 Arctic Winter by Using an Improved Micropulse Lidar  

Science Conference Proceedings (OSTI)

The potential of a new improved version of micropulse lidar (MPL-4) on polar stratospheric cloud (PSC) detection is evaluated in the Arctic over Ny-Ålesund (79°N, 12°E), Norway. The campaign took place from January to February 2007 in the frame ...

Carmen Cordoba-Jabonero; Manuel Gil; Margarita Yela; Marion Maturilli; Roland Neuber

2009-10-01T23:59:59.000Z

126

Factors influencing the microphysics and radiative properties of liquid-dominated Arctic clouds: insight from observations of aerosol and clouds during ISDAC  

SciTech Connect

Aircraft measurements during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in April 2008 are used to investigate aerosol indirect effects in Arctic clouds. Two aerosol-cloud regimes are considered in this analysis: single-layer stratocumulus cloud with below-cloud aerosol concentrations (N{sub a}) below 300 cm{sup -3} on April 8 and April 26-27 (clean cases); and inhomogeneous layered cloud with N{sub a} > 500 cm{sup -3} below cloud base on April 19-20, concurrent with a biomass burning episode (polluted cases). Vertical profiles through cloud in each regime are used to determine average cloud microphysical and optical properties. Positive correlations between the cloud droplet effective radius (Re) and cloud optical depth ({tau}) are observed for both clean and polluted cases, which are characteristic of optically-thin, non-precipitating clouds. Average Re values for each case are {approx} 6.2 {mu}m, despite significantly higher droplet number concentrations (Nd) in the polluted cases. The apparent independence of Re and Nd simplifies the description of indirect effects, such that {tau} and the cloud albedo (A) can be described by relatively simple functions of the cloud liquid water path. Adiabatic cloud parcel model simulations show that the marked differences in Na between the regimes account largely for differences in droplet activation, but that the properties of precursor aerosol also play a role, particularly for polluted cases where competition for vapour amongst the more numerous particles limits activation to larger and/or more hygroscopic particles. The similarity of Re for clean and polluted cases is attributed to compensating droplet growth processes for different initial droplet size distributions.

Earle, Michael; Liu, Peter S.; Strapp, J. Walter; Zelenyuk, Alla; Imre, D.; McFarquhar, Greg; Shantz, Nicole C.; Leaitch, W. R.

2011-11-04T23:59:59.000Z

127

Q. J. R. Meteorol. Soc. (2006), 132, pp. 16931715 doi: 10.1256/qj.05.145 Evaluation of a large-eddy model simulation of a mixed-phase altocumulus  

E-Print Network (OSTI)

of mixed-phase clouds, the case shows the importance of using: (i) separate prognostic ice and liquid water-eddy model simulation of a mixed-phase altocumulus cloud using microwave radiometer, lidar and Doppler radar February 2006) SUMMARY Using the Met Office large-eddy model (LEM) we simulate a mixed-phase altocumulus

Hogan, Robin

128

Parameterizing Size Distribution in Ice Clouds  

SciTech Connect

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.

DeSlover, Daniel; Mitchell, David L.

2009-09-25T23:59:59.000Z

129

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

SciTech Connect

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.

Greg M. McFarquhar

2010-02-22T23:59:59.000Z

130

turner_poster.arctic_bbhrp.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

into different classes: "single-layer" and "double-layer" clouds of liquid-only, mixed-phase, and ice-only clouds. * A cloud layer is a vertically continuous region of the...

131

Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies  

E-Print Network (OSTI)

reduced rate of ice formation in mixed- phase Arctic cloudsincreases occur in phase with sea ice melt, potentiallyIce properties of single-layer stratocumulus during the Mixed-Phase

Quinn, P.K.

2008-01-01T23:59:59.000Z

132

Interannual Variations of Arctic Cloud Types in Relation to Sea Ice  

Science Conference Proceedings (OSTI)

Sea ice extent and thickness may be affected by cloud changes, and sea ice changes may in turn impart changes to cloud cover. Different types of clouds have different effects on sea ice. Visual cloud reports from land and ocean regions of the ...

Ryan Eastman; Stephen G. Warren

2010-08-01T23:59:59.000Z

133

Using A-Train Arctic cloud observations to constrain and improve...  

NLE Websites -- All DOE Office Websites (Extended Search)

radiation anomalies to the 2007 Arctic sea ice loss Jennifer E. Kay 1,2 Andrew Gettelman 1 , Tristan L'Ecuyer 2 ,Graeme Stephens 2 , and Chris O'Dell 2 1 National Center for...

134

The Influence of Solar Zenith Angle and Cloud Type on Cloud Radiative Forcing at the Surface in the Arctic  

Science Conference Proceedings (OSTI)

Measurements of the long- and shortwave incident radiation taken from the USCGC Polar Sea during a research cruise to the Northeast Water Polynya during the summer of 1993 are analyzed together with observations of cloud type and amount to ...

Peter J. Minnett

1999-01-01T23:59:59.000Z

135

Use of ARM/NSA Data to Validate and Improve the Remote Sensing Retrieval of Cloud and Surface Properties in the Arctic from AVHRR Data  

NLE Websites -- All DOE Office Websites (Extended Search)

ARM/NSA Data to Validate and Improve the ARM/NSA Data to Validate and Improve the Remote Sensing Retrieval of Cloud and Surface Properties in the Arctic from AVHRR Data X. Xiong QSS Group, Inc. National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service Office of Research and Applications Camp Springs, Maryland R. Storvold and C. Marty Geophysical Institute University of Alaska Fairbanks, Alaska K. H. Stamnes Stevens Institute of Technology Hoboken, New Jersey B. D. Zak Sandia National Laboratories Albuquerque, New Mexico Introduction Clouds in the Arctic have an important impact on the radiative energy balance. However, the effects of clouds still constitute one of the largest uncertainties in the study of climate change. Because the surface

136

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

E-Print Network (OSTI)

supersaturation in mixed-phase clouds is the saturation vapor pressure weighted by the proportions of ice to be in the liquid phase for clouds warmer than -35ĀŗC, and is assumed to be in the ice phase for cirrus clouds. The conversion of this detrained condensate from liquid phase into the ice phase in the mixed-phase clouds

Meskhidze, Nicholas

137

Aerosol Effects on Cloud Emissivity and Surface Longwave Heating in the Arctic  

Science Conference Proceedings (OSTI)

Increases in anthropogenic aerosols in the atmosphere tend to increase the reflectance of solar (shortwave) radiation from water clouds, which can lead to lower surface temperatures. Here an opposing effect whereby aerosols increase the longwave ...

Timothy J. Garrett; Lawrence F. Radke; Peter V. Hobbs

2002-02-01T23:59:59.000Z

138

Numerical Simulations of Observed Arctic Stratus Clouds Using a Second-Order Turbulence Closure Model  

Science Conference Proceedings (OSTI)

A high-resolution one-dimensional version of a second-order turbulence closure radiative-convective model, developed at Los Alamos National Laboratory, is used to simulate the interactions among turbulence, radiation, and bulk cloud parameters in ...

W. S. Smith; C-Y. J. Kao

1996-01-01T23:59:59.000Z

139

Evaluation of an AVHRR Cloud Detection and Classification Method over the Central Arctic Ocean  

Science Conference Proceedings (OSTI)

A cloud classification method that uses both multispectral and textural features with a maximum likelihood discriminator is applied to full-resolution AVHRR (Advanced Very High Resolution Radiometer) data from 100 NOAA polar-orbiter overpasses ...

Dan Lubin; Esther Morrow

1998-02-01T23:59:59.000Z

140

An Improved Parameterization for Simulating Arctic Cloud Amount in the CCSM3 Climate Model  

Science Conference Proceedings (OSTI)

A simple alternative parameterization for predicting cloud fraction in the Community Climate System Model, version 3 (CCSM3) global climate model is presented. This formula, dubbed “freeezedry,” is designed to alleviate the bias of excessive low ...

Steve Vavrus; Duane Waliser

2008-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

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

Science Conference Proceedings (OSTI)

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.

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

142

How Well Do Regional Climate Models Reproduce Radiation and Clouds in the Arctic? An Evaluation of ARCMIP Simulations  

Science Conference Proceedings (OSTI)

Downwelling radiation in six regional models from the Arctic Regional Climate Model Intercomparison (ARCMIP) project is systematically biased negative in comparison with observations from the Surface Heat Budget of the Arctic Ocean (SHEBA) ...

Michael Tjernström; Joseph Sedlar; Matthew D. Shupe

2008-09-01T23:59:59.000Z

143

Cloud Properties Working Group Break Out Session  

NLE Websites -- All DOE Office Websites (Extended Search)

(Kollias; Albecht) Q2: Growth of ice crystals in different environments: Ice initiation, ice growth regimes, precipitation formation, mixed-phase cloud lifecycle. (Korolev) Q3:...

144

ARM - Field Campaign - Fall 1997 Cloud IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

and with surface instruments. Cloud types of interest included single-layer liquid phase, ice-phase, and mixed-phase clouds, as well as multi-layered conditions. To some degree,...

145

Impact of cloud microphysics on squall line organization  

NLE Websites -- All DOE Office Websites (Extended Search)

of turbulent- microphysical interactions and impact on optical properties. * Mixed-phase and ice clouds. We will use microphysical retrievals and aircraft observations from...

146

Arctic Surface, Cloud, and Radiation Properties Based on the AVHRR Polar Pathfinder Dataset. Part I: Spatial and Temporal Characteristics  

Science Conference Proceedings (OSTI)

With broad spectral coverage and high spatial and temporal resolutions, satellite sensors can provide the data needed for the analysis of spatial and temporal variations of climate parameters in data-sparse regions such as the Arctic and ...

Xuanji Wang; Jeffrey R. Key

2005-07-01T23:59:59.000Z

147

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

E-Print Network (OSTI)

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

Shupe, Matthew

148

Optical Properties and Phase of Some Midlatitude, Midlevel Clouds in ECLIPS  

Science Conference Proceedings (OSTI)

Several cloud optical quantities were measured for the first time in midlevel, mixed-phase clouds. These included cloud infrared emittance and absorption coefficient (10–12 ?m), effective backscatter-to-extinction ratio, and lidar depolarization ...

S. A. Young; C. M. R. Platt; R. T. Austin; G. R. Patterson

2000-02-01T23:59:59.000Z

149

Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties  

E-Print Network (OSTI)

ice nucleation in ice and mixed- phase clouds are: 1. WhatWhat is the phase, hygroscopicity, and warm and ice cloudmixed phase clouds, while cirrus clouds are composed of ice

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

150

Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

heated by the sun, produces rising columns of air in which the moisture condenses into tall fleecy white clouds At night, when the sky is clear, the earth cools to give those...

151

Synoptic sensitivities of subtropical clouds separating aerosol effects from meteorology  

E-Print Network (OSTI)

identi?ed as liquid, ice, mixed phase, or uncertain. Here wePhase Infrared Day Histogram Counts Cloud Fraction Liquid Cloud Fraction Iceice as well as the di?erent temperatures at which each phase

Mauger, Guillaume S.

2008-01-01T23:59:59.000Z

152

EVALUATING CLOUD RETRIEVAL ALGORITHMS WITH THE ARM BBHRP FRAMEWORK  

E-Print Network (OSTI)

of liquid, ice, and mixed-phase clouds have been processed in BBHRP for the ACRF Southern Great Plains (SGP, and phase of clouds above each ACRF site. Various approaches to retrieve the microphysical properties, including those from Microbase, the current `reference' retrieval approach in BBHRP. At the NSA, mixed-phase

153

Estimations of Cloud Optical Thickness from Ground-Based Measurements of Incoming Solar Radiation in the Arctic  

Science Conference Proceedings (OSTI)

A technique for evaluation of cloud optical thickness (plant-parallel, homogeneous layer) from ground-based measurements of incoming solar irradiance using a simple radiation model is introduced. The sensitivities of downward and upward fluxes of ...

E. Leontyeva; K. Stamnes

1994-04-01T23:59:59.000Z

154

Non-stoichiometric mixed-phase titania photocatalyst  

SciTech Connect

A mixed anatase-rutile phase, non-stoichiometric titania photocatalyst material is a highly reactive and is a UV and visible light responsive photocastalyst in the as-deposited condition (i.e. without the need for a subsequent thermal treatment). The mixed phase, non-stoichiometric titania thin film material is non-stoichiometric in terms of its oxygen content such that the thin film material shows a marked red-shift in photoresponse.

Chen, Le (Lakewood, CO); Gray, Kimberly A. (Evanston, IL); Graham, Michael E. (Evanston, IL)

2012-06-19T23:59:59.000Z

155

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

super-cooled liquid in them. If these clouds also contain ice, they are called mixed-phase clouds. Because mixed-phase clouds are particularly common in the Arctic and because...

156

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

SciTech Connect

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.

Michael R. Poellot

2009-01-09T23:59:59.000Z

157

Homogeneous Nucleation Rate for Highly Supercooled Cirrus Cloud Droplets  

Science Conference Proceedings (OSTI)

A mixed-phase hydrometer growth model has been applied to determining the nucleation mode and rate responsible for the glaciation of a highly supercooled liquid cloud studied jointly by ground-based polarization lidar and aircraft in situ probes. ...

Kenneth Sassen; Gregory C. Dodd

1988-04-01T23:59:59.000Z

158

A Method for Adaptive Habit Prediction in Bulk Microphysical Models. Part III: Applications and Studies within a Two-Dimensional Kinematic Model  

Science Conference Proceedings (OSTI)

Arctic mixed-phase clouds are ubiquitous, and the persistence of supercooled liquid is not well understood. Prior studies of mixed-phase clouds predict a single axis length assuming spherical particles or mass–dimensional relationships derived ...

Kara J. Sulia; Jerry Y. Harrington; Hugh Morrison

2013-10-01T23:59:59.000Z

159

Microsoft Word - wang_z.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Algorithms The Mixed-Phase Cloud Microphysical Property Retrieval Supercooled water with ice virga is a typical type of mixed-phase cloud in arctic, which can be generally...

160

DRAFT, Revised June 2012 Aerosol cloud-mediated radiative forcing: highly uncertain and  

E-Print Network (OSTI)

clouds is even lower than for the shallow clouds, as mixed phase and ice processes play an important role state of cloud and aerosol parameterizations, but intense research efforts aimed at improving. Respectively, the parameterization of these processes for GCMs is further away than for the low clouds

Daniel, Rosenfeld

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Observational Constraints on the Cloud Thermodynamic Phase in Midlatitude Storms CATHERINE M. NAUD  

E-Print Network (OSTI)

in the ice versus the liquid phase. Early prognostic cloud water parameterizations for stratiform clouds supercooled liquid water gradually gives way to ice in the mixed-phase regions of clouds are still poorlyObservational Constraints on the Cloud Thermodynamic Phase in Midlatitude Storms CATHERINE M. NAUD

162

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)

- 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

Stuart, Amy L.

163

The Retrieval of Stratus Cloud Droplet Effective Radius with Cloud Radars  

Science Conference Proceedings (OSTI)

In situ samples of cloud droplets by aircraft in Oklahoma in 1997, the Surface Heat Budget of the Arctic Ocean (SHEBA)/First ISCCP Regional Experiment (FIRE)-Arctic Cloud Experiment (ACE) in 1998, and various other locations around the world were ...

Shelby Frisch; Matthew Shupe; Irina Djalalova; Graham Feingold; Michael Poellot

2002-06-01T23:59:59.000Z

164

Thin Liquid Water Clouds: Their Importance and Our Challenge  

Science Conference Proceedings (OSTI)

Many of the clouds important to the Earth's energy balance, from the Tropics to the Arctic, contain small amounts of liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (...

D. D. Turner; A. M. Vogelmann; K. Johnson; M. Miller; R. T. Austin; J. C. Barnard; C. Flynn; C. Long; S. A. McFarlane; K. Cady-Pereira; S. A. Clough; J. C. Chiu; M. M. Khaiyer; J. Liljegren; B. Lin; P. Minnis; A. Marshak; S. Y. Matrosov; Q. Min; W. O'Hirok; Z. Wang; W. Wiscombe

2007-02-01T23:59:59.000Z

165

Arctic house  

E-Print Network (OSTI)

Currently available housing in the Arctic is limited to solutions that have been adapted from designs for less severe climates. This thesis has developed a new manner of residential construction designed specifically for ...

Turkel, Joel A. (Joel Abram), 1969-

1999-01-01T23:59:59.000Z

166

Multiparameter AVHRR-Derived Products for Arctic Climate Studies  

Science Conference Proceedings (OSTI)

Generation and sample applications of an integrated set of remotely sensed products for investigations of Arctic climate are described. Cloud fraction, ice surface temperature, surface albedo, downwelling radiative fluxes, ice motion vectors, and ...

Walter N. Meier; James A. Maslanik; Charles W. Fowler; Jeffrey R. Key

1997-01-01T23:59:59.000Z

167

Liquid-gas mixed phase in nuclear matter at finite temperature  

E-Print Network (OSTI)

We explore the geometrical structure of Liquid-gas (LG) mixed phase which is relevant to nuclear matter in the crust region of compact stars or supernovae. To get the equation of state (EOS) of the system, the Maxwell construction is found to be applicable to symmetric nuclear matter, where protons and neutrons behave simultaneously. For asymmetric nuclear matter, on the other hand, the phase equilibrium can be obtained by fully solving the Gibbs conditions since the components in the L and G phases are completely different. We also discuss the effects of surface and the Coulomb interaction on the mixed phase.

Toshiki Maruyama; Toshitaka Tatsumi

2010-09-07T23:59:59.000Z

168

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

E-Print Network (OSTI)

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

Wood, Robert

169

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

SciTech Connect

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.

Luke,E.; Kollias, P.

2007-08-06T23:59:59.000Z

170

Research Highlight  

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The Influence of Parameterized Ice Habit on Simulated Mixed-Phase Arctic Clouds Download a printable PDF Submitter: Harrington, J. Y., Pennsylvania State University Avramov, A.,...

171

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

change, with potentially dramatic consequences for the regional ecosystem. Arctic mixed-phase clouds, comprising both ice and supercooled liquid water, have been observed to...

172

Chemical and Physical Properties of Atmospheric Aerosols (a) A Case Study in the Unique Properties of Agricultural Aerosols (b) The Role of Chemical Composition in Ice Nucleation during the Arctic Spring  

E-Print Network (OSTI)

This study focuses on the analysis of atmospheric particles sampled from two different field campaigns: the field study at a cattle feeding facility in the summer from 2005 to 2008 and the Indirect and Semi-Direct Aerosol Campaign (ISDAC) in 2008. A ground site field study at a representative large cattle feeding facility in the Texas Panhandle was conducted to characterize the particle size distributions, hygroscopicity, and chemical composition of agricultural aerosols. Here, a first comprehensive dataset is reported for these physical and chemical properties of agricultural aerosols appropriate for use in a site-specific emission inventory. The emission rate and transport of the aerosols are also discussed. In addition, mixing ratios of total and gaseous ammonia were measured at the same field in 2007 and 2008. Measurements such as these provide a means to determine whether the fugitive dust emitted from a typical large feedlot represents a health concern for employees of the feeding operation and the nearby community. Detailed chemical composition of aircraft-sampled particles collected during ISDAC was studied. Filter samples were collected under a variety of conditions in and out of mixed phase and ice clouds in the Arctic. Specifically, particles were sampled from a mixed-phase cloud during a period of observed high concentrations of ice nuclei (IN), a biomass plume, and under relatively clean ambient conditions. Composition of particles was studied on a particle-by-particle basis using several microspectroscopy techniques. Based on the elemental composition analysis, more magnesium was found in Arctic cloud residues relative to ambient air. Likewise, based on the carbon speciation analysis, high IN samples contained coated inorganics, carbonate, and black or brown carbon particles. In the samples collected during a flight through a biomass burning plume, water-soluble organic carbon was the dominant overall composition. Due to their hygroscopic nature, these organics may preferably act as cloud condensation nuclei (CCN) rather than IN. Other ambient samples contained relatively higher fractions of organic and inorganic mixtures and less purely water-soluble organics than found in the biomass particles. The most likely source of inorganics would be sea salt. When present, sea salt may further enhance ice nucleation.

Moon, Seong-Gi

2010-05-01T23:59:59.000Z

173

The Arctic Lower Troposphere Observed Structure (ALTOS) Campaign  

SciTech Connect

The ALTOS campaign focuses on operating a tethered observing system for routine in situ sampling of low-level (< 2 km) Arctic clouds. It has been a long-term hope to fly tethered systems at Barrow, Alaska, but it is clear that the Federal Aviation Administration (FAA) will not permit in-cloud tether systems at Barrow, even if unmanned aerial vehicle (UAV) operations are allowed in the future. We have provided the scientific rationale for long-term, routine in situ measurements of cloud and aerosol properties in the Arctic. The existing restricted air space at Oliktok offers an opportunity to do so.

Verlinde, J

2010-10-18T23:59:59.000Z

174

Discrimination of Mixed- versus Ice-Phase Clouds Using Dual-Polarization Radar with Application to Detection of Aircraft Icing Regions  

Science Conference Proceedings (OSTI)

Dual-polarization radar measurements and in situ measurements of supercooled liquid water and ice particles within orographic cloud systems are used to develop probabilistic criteria for identifying mixed-phase versus ice-phase regions of sub-0°C ...

David M. Plummer; Sabine Göke; Robert M. Rauber; Larry Di Girolamo

2010-05-01T23:59:59.000Z

175

Microwave radiative transfer in the mixed-phase regions of tropical rainfall  

E-Print Network (OSTI)

Current physically-based Radiative Transfer Model (RTM) algorithms for estimating oceanic rain use a very simplified hydrometeor profile that ignores the mixed-phase regions (Wilheit et al., 1977). However, to estimate hydrometeor profiles more reasonably in the tropical precipitation regions, understanding of the brightness temperature (Tb) variations in the mixed-phase regions is essential. Further, establishing physical assumptions for microwave radiative transfer in the mixed-phase regions is necessary for quantifying and minimizing the uncertainties in the rainfall retrieval. Consequently, the objective of this study was to quantify uncertainties and to achieve a solid basis for improvement of the current rainfall retrieval, which is based on an RTM. To accomplish this, we examined data taken by the Convair-580 aircraft during the KWAJEX (Kwajalein Experiment). In order to calculate radiative transfer, the AMMR (Airborne Multi-channel Microwave Radiometer) data were combined with radiosonde data and aircraft microphysics data. Analyses were performed for the stratiform and convective rainfall regions respectively. In stratiform precipitation with a bright band, the main concern was to examine the needed physical assumptions for describing the abrupt change of Tb just below the freezing level. In the case of convective precipitation, the focus was to investigate the effective additional rain layer thickness corresponding to the super-cooled water layer above the freezing level. From the results, it was required to assume the bright-band (around 1/2 km below the FL) as having 2 times the absorption as the rain below to explain the Tb variation due to the phase change of hydrometeors. On the other hand, in the case of convective rainfall, it was suggested that approximately from 1/4km to 3km of super-cooled layer thickness should be considered to describe the additional hydrometeor layer due to the strong updrafts in the convective regions.

Jin, Kyoung-Wook

2001-01-01T23:59:59.000Z

176

Final measurement of $B^0_s$ mixing phase in the full CDF Run II data set  

E-Print Network (OSTI)

We report the final CDF measurement of the $B^0_s$ mixing phase, mean lifetime, and decay-width difference through the fit of the time evolution of flavor-tagged $B^0_s \\rightarrow J/\\psi \\phi$ decays. The measurement is based on the full data set of 1.96 TeV $p\\bar{p}$ collisions collected between February 2002 and September 2011 by the CDF experiment. The results are consistent with the standard model and other experimental determinations and are amongst the most precise to date.

Sabato Leo

2012-07-28T23:59:59.000Z

177

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

SciTech Connect

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.

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

178

Improved Airborne Hot-Wire Measurements of Ice Water Content in Clouds  

Science Conference Proceedings (OSTI)

Airborne measurements of ice water content (IWC) in both ice and mixed phase clouds remain one of the long standing problems in experimental cloud physics. For nearly three decades, IWC has been measured with the help of the Nevzorov hot-wire ...

A. Korolev; J. W. Strapp; G. A. Isaac; E. Emery

179

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

E-Print Network (OSTI)

and supersaturation in CAM. The new model is able to reproduce field observations of ice mass and mixed phase cloudGlobal simulations of ice nucleation and ice supersaturation with an improved cloud scheme; accepted 3 June 2010; published 28 September 2010. [1] A processbased treatment of ice supersaturation

Gettelman, Andrew

180

HIGH SPECTRAL RESOLUTION LIDAR EMULATION VIA DOPPLER CLOUD RADAR SPECTRUM PROCESSING AND ITS IMPLICATIONS FOR  

E-Print Network (OSTI)

targeting the liquid, and radar, the ice. Depolarization measurements can assist in resolving phase to identify liquid, ice, and mixed-phase clouds. __________ NOTICE: This manuscript has been authored IMPLICATIONS FOR CLOUD PHASE IDENTIFICATION E. Luke, P. Kollias, and M. Shupe Presented at the American

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

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)

the importance of these interactions and the dif- ficulty in parameterizing clouds due to the wide range prognostic variables for cloud liquid and ice mass, specification of the effective cloud particle size for treating radiative interactions, and limited treatment of mixed-phase processes. There are several

Gettelman, Andrew

182

Nonaqueous seeded growth of flower-like mixed-phase titania nanostructures for photocatalytic applications  

SciTech Connect

A nonaqueous seeded-grown synthesis of three-dimensional TiO{sub 2} nanostructures in the benzyl alcohol reaction system was reported. The synthesis was simple, high-yield, and requires no structural directing or capping agents. It could be largely accelerated by applying microwave heating. The TiO{sub 2} nanostructures had a unique flower-like morphology and high surface area. Furthermore, the structural analyses suggested that the nanostructures had a non-uniform distribution of crystalline phases, with the inner part rich in anatase and the outer part rich in rutile. After heat treatments, the mixed-phase TiO{sub 2} nanostructures exhibited high photocatalytic activities for the photodegradation of methylene blue as compared to Degussa P25. The high photoactivities may be associated with the high surface area and the synergistic effect resulting from the anisotropic mixed-phase nanostructures. The results demonstrate the uniqueness of the nonaqueous seeded growth and the potential of the TiO{sub 2} nanostructures for practical applications. - Graphical abstract: Flower-like TiO{sub 2} nanostructures synthesized by a nonaqueous seeded growth without using any structural directing or capping agents.

Hsu, Y.-C.; Lin, H.-C.; Chen, C.-H.; Liao, Y.-T. [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Yang, C.-M., E-mail: cmyang@mx.nthu.edu.t [Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2010-09-15T23:59:59.000Z

183

Toward an Explanation of the Annual Cycle of Cloudiness over the Arctic Ocean  

Science Conference Proceedings (OSTI)

The annual cycle of low cloud amount over the Arctic Ocean is examined using climatological data and a radiative-turbulent column model. Three hypotheses for the annual cycle are formulated, compared with climatological data for consistency, and ...

J. A. Beesley; R. E. Moritz

1999-02-01T23:59:59.000Z

184

Theory for Dual-Wavelength C02 Lidar Method to Distinguish Ice, Mixed-Phase, and Water Clouds  

Science Conference Proceedings (OSTI)

An analytical study shows that the ratio of backscatter from ice particles at two CO2 lidar wavelengths is substantially different from the ratio from water drops. This forms the basis for a new method to discriminate between ice, water, and ...

Wynn L. Eberhard

1995-02-01T23:59:59.000Z

185

The Arctic Haze Phenomenon  

Science Conference Proceedings (OSTI)

The arctic atmosphere is the repository for surprisingly high concentrations of pollutants throughout the winter months. The polluted air mass in question includes virtually all the atmosphere above the Arctic Circle and also two great lobes that ...

Glenn E. Shaw

1995-12-01T23:59:59.000Z

186

ARM - Field Campaign - Boundary Layer Cloud IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsBoundary Layer Cloud IOP govCampaignsBoundary Layer Cloud IOP Campaign Links Campaign Images Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Boundary Layer Cloud IOP 2005.07.11 - 2005.08.07 Lead Scientist : William Shaw For data sets, see below. Description Investigators from Pacific Northwest National Laboratory, in collaboration with scientists from a number of other institutions, carried out a month of intensive measurements at the ARM Climate Research Facility on the North Slope of Alaska in the summer of 2005. The purpose of these measurements was to determine how much the arctic land surface modifies the way low clouds reflect, absorb, and transmit solar and infrared radiation. This is an important problem because arctic clouds play a prominent role in

187

PowerPoint Presentation - No Slide Title  

NLE Websites -- All DOE Office Websites (Extended Search)

Arctic mixed-phase clouds: Arctic mixed-phase clouds: Sensitivity to ice initiation mechanisms Igor Sednev (isednev@lbl.gov) and Surabi Menon (smenon@lbl.gov) Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Motivation The impacts of Arctic mixed-phase clouds on climate in terms of changes in surface radiative budgets remain uncertain due to the complexities in representation of mixed-phase clouds. The environmental conditions that determine Arctic cloud properties need to be thoroughly analyzed to fully represent these clouds in climate models. To evaluate the impact of ice initiation mechanisms on cloud glaciation time and develop a simplified bulk microphysics scheme for use in GCMs we use a modified version of the GISS SCM initialized with data from the DOE Arctic

188

ARM - Publications: Science Team Meeting Documents: Clouds and radiation in  

NLE Websites -- All DOE Office Websites (Extended Search)

Clouds and radiation in the Arctic coastal system - effects of local Clouds and radiation in the Arctic coastal system - effects of local heterogeneity Key, Erica University of Miami, RSMAS Minnett, Peter University of Miami Improving our comprehension of the influence of clouds in the polar regions is important as a prerequisite to refining our understanding of the earth's climate system. Polar clouds modulate the radiative heat loss to space in the regions that serve as the heat sink of the climate system. The local feedbacks between cloud formation and changing surface albedo that result from the ice melting and refreezing cycle, and the small space scales over which significant gradients occur, render this a very complex system to study. Difficulties in making appropriate measurements in the harsh Arctic environment lead to sparse, if not absent information on the

189

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Weather and Forecasting During Mixed-Phase Arctic Weather and Forecasting During Mixed-Phase Arctic Cloud Experiment V.T. Yannuzzi, E. Clothiaux, H. Verlinde, and J. Harrington Department of Meteorology Pennsylvania State University Mont Alto, Pennsylvania Introduction and Important Events Prior to Mixed-Phase Arctic Cloud Experiment The Mixed-Phase Arctic Cloud Experiment (MPACE) was conducted across the North Slope of Alaska (NSA) during September 27-October 22, 2004. The experiment was funded by the Department of Energy (DOE)-Atmospheric Radiation Measurement (ARM) with the intention of increasing our knowledge about mixed-phase clouds in the arctic. In addition to radiosonde launches from four sites, lidar provided by the University of Wisconsin and the University of Alaska Fairbanks were used in

190

ARM - Publications: Science Team Meeting Documents  

NLE Websites -- All DOE Office Websites (Extended Search)

and spring mixed-phase clouds. This explicit model has been used to develop a parameterization of the Arctic low-level clouds such as clear-sky precipitation, ice fog and...

191

Storm Peak Lab Cloud Property Validation  

NLE Websites -- All DOE Office Websites (Extended Search)

Storm Peak Lab Cloud Storm Peak Lab Cloud Property Validation Experiment (STORMVEX) Operated by the Atmospheric Radiation Measurement (ARM) Climate Research Facility for the U.S. Department of Energy, the second ARM Mobile Facility (AMF2) begins its inaugural deployment November 2010 in Steamboat Springs, Colorado, for the Storm Peak Lab Cloud Property Validation Experiment, or STORMVEX. For six months, the comprehensive suite of AMF2 instruments will obtain measurements of cloud and aerosol properties at various sites below the heavily instrumented Storm Peak Lab, located on Mount Werner at an elevation of 3220 meters. The correlative data sets that will be created from AMF2 and Storm Peak Lab will equate to between 200 and 300 in situ aircraft flight hours in liquid, mixed phase, and precipitating

192

Factors Influencing Simulated Changes in Future Arctic Cloudiness  

Science Conference Proceedings (OSTI)

This study diagnoses the changes in Arctic clouds simulated by the Community Climate System Model version 3 (CCSM3) in a transient 2 × CO2 simulation. Four experiments—one fully coupled and three with prescribed SSTs and/or sea ice cover—are used ...

Stephen J. Vavrus; Uma S. Bhatt; Vladimir A. Alexeev

2011-09-01T23:59:59.000Z

193

Warming Trends in the Arctic from Clear Sky Satellite Observations  

Science Conference Proceedings (OSTI)

Satellite thermal infrared data on surface temperatures provide pan-Arctic coverage from 1981 to 2001 during cloud-free conditions and reveal large warming anomalies in the 1990s compared to the 1980s and regional variability in the trend. The ...

Josefino C. Comiso

2003-11-01T23:59:59.000Z

194

IC cloud: Enabling compositional cloud  

Science Conference Proceedings (OSTI)

Cloud computing has attracted great interest from both academic and industrial communities. Different paradigms, architectures and applications based on the concept of cloud have emerged. Although many of them have been quite successful, efforts are ... Keywords: Cloud computing, cloud elasticity, cloud service, compositional cloud, infrastructure as a service (IaaS)

Yi-Ke Guo; Li Guo

2011-08-01T23:59:59.000Z

195

Comparison of Airborne In Situ, Airborne Radar–Lidar, and Spaceborne Radar–Lidar Retrievals of Polar Ice Cloud Properties Sampled during the POLARCAT Campaign  

Science Conference Proceedings (OSTI)

This study illustrates the high potential of RALI, the French airborne radar–lidar instrument, for studying cloud processes and evaluating satellite products when satellite overpasses are available. For an Arctic nimbostratus ice cloud collected ...

Julien Delanoė; Alain Protat; Olivier Jourdan; Jacques Pelon; Mathieu Papazzoni; Régis Dupuy; Jean-Francois Gayet; Caroline Jouan

2013-01-01T23:59:59.000Z

196

NETL: Arctic Energy Office  

NLE Websites -- All DOE Office Websites (Extended Search)

The Arctic Energy Office image showing Alaska landscape Alaska North Slope Resources Alaska Unconventional Resources ChallengesShortages AEO Program Fact Sheet Alaskas fossil...

197

Thermodynamic phase profiles of optically thin midlatitude clouds and their relation to temperature  

E-Print Network (OSTI)

parameterizations of cloud phase in general circulation models. However, other aircraft campaigns and different in the Arctic. The relationship between ice phase occurrence and temperature only slightly changes between cloud interest, as they occur in a temperature range where cloud phase can either be liquid, ice, or mixed

198

Arctic Lower Troposphere Observed Structure (ALTOS)  

NLE Websites -- All DOE Office Websites (Extended Search)

Lower Troposphere Observed Structure (ALTOS) Lower Troposphere Observed Structure (ALTOS) will raise and lower a heavily instrumented tethered balloon system at regular intervals in the lower 2 kilometers of the atmosphere at Oliktok Point. Data obtained during the ALTOS campaign will provide a statistically significant set of observed in situ cloud properties for validating retrieval algorithms and help scientists reduce the uncertainty in the radiative forcing and heating rates on hourly time scales. The data will also help researchers gain a better understanding of the driving processes that control climate changes and determine the state of the Arctic climate system. Collaborators Science Team: The Pennsylvania State University, Stratton

199

The Impact of Polar Stratospheric Clouds on the Heating Rates of the Winter Polar Stratosphere  

Science Conference Proceedings (OSTI)

We have computed the perturbation to the infrared radiative heating rates of the lower stratosphere due to the occurrence of polar stratospheric clouds (PSCs) during the winter season in the Antarctic and Arctic regions. The calculations were ...

James B. Pollack; Christopher P. McKay

1985-02-01T23:59:59.000Z

200

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

E-Print Network (OSTI)

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

Harrington, Jerry Y.

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Two-moment Bulk Stratiform Cloud Microphysics in the Grid-point Atmospheric Model of IAP LASG (GAMIL)  

SciTech Connect

A two-moment bulk stratiform microphysics scheme, including recently developed physically-based droplet activation/ice nucleation parameterizations has been implemented into the Grid-point Atmospheric Model of IAP LASG (GAMIL) as an effort to enhance the model capability for studying aerosol indirect effects. Unlike the previous one-moment cloud microphysics scheme, the new scheme produces reasonable representation of cloud particle size and number concentration. This scheme captures the observed spatial variations in cloud droplet number concentrations. Simulated ice crystal number concentrations in cirrus clouds qualitatively agree with in-situ observations. The longwave and shortwave cloud forcing are in better agreement with observations. Sensitivity tests show that the column cloud droplet number concentrations calculated from two different droplet activation parameterizations are similar. However, ice crystal number concentration in mixed-phased clouds is sensitive to different heterogeneous freezing formulations. The simulation with high ice crystal number concentration in mixed-phase clouds has less liquid water path and weaker cloud forcing. Furthermore, ice crystal number concentration in cirrus clouds is sensitive to different ice nucleation parameterizations. Sensitivity tests also suggest that impact of pre-existing ice crystals on homogeneous freezing in old clouds should be taken into account.

Shi, Xiangjun; Wang, Bin; Liu, Xiaohong; Wang, Minghuai

2013-05-01T23:59:59.000Z

202

Arctic Solar | Open Energy Information  

Open Energy Info (EERE)

search Name Arctic Solar Place G"LLIVARE, Sweden Zip SE- 98228 Product manufacturers of PV modules References Arctic Solar1 LinkedIn Connections CrunchBase Profile No...

203

Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

This paper reviews the current knowledge of the climatological, structural, and organizational aspects of stratocumulus clouds and the physical processes controlling them. More of Earth’s surface is covered by stratocumulus clouds than by any ...

Robert Wood

2012-08-01T23:59:59.000Z

204

1  

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Case Study of Horizontal Variability in Arctic Cloud Case Study of Horizontal Variability in Arctic Cloud Microphysical Properties M. Poellot and D. Brown Department of Atmospheric Sciences University of North Dakota Grand Forks, North Dakota Overview The importance of arctic cloud properties to the surface radiative flux budget is well known, and accurate representation of these clouds is essential to proper modeling of the arctic environment. One of the interesting characteristics of arctic clouds is the prevalence of mixed phase cloud layers. In these mixed-phase clouds, the water content tends to dominate the radiative effects, causing them to act as all liquid clouds. Measurements have shown these clouds to be highly inhomogeneous in terms of ice and liquid water content. The horizontal dimension is important to proper interpretation of remotely sensed

205

The Effects of Clouds on Aerosol and Chemical Species Production and Distribution. Part III: Aerosol Model Description and Sensitivity Analysis  

Science Conference Proceedings (OSTI)

A modeling study of the effects of clouds on the evolution and redistribution of aerosol particles in the troposphere is presented. A two-mode, two-moment aerosol evolution model is coupled with a two-dimensional, mixed-phase, two-moment ...

Yiping Zhang; Sonia Kreidenweis; Gregory R. Taylor

1998-03-01T23:59:59.000Z

206

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

McFarquhar, G. Zhang, M.R. Poellot, P.J. DeMott, A.J. Prenni and A.J. Heymsfield, 2007: Ice properties of single-layer stratocumulus during the Mixed-Phase Arctic Cloud...

207

ARM - Technical Reports  

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747KB) McFarquhar, GM, and J Um 2012 Parameterization of the Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds during the ISDAC Field Campaign (PDF, 5.0MB) Korolev, A,...

208

Executive Summary  

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The Mixed-Phase Arctic Cloud Experiment (M-PACE) November 2005 Hans Verlinde Pennsylvania State University University Park, Pennsylvania Work supported by the U.S. Department of...

209

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

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5 5 Posters A One-Dimensional Radiative Convective Model with Detailed Cloud Microphysics J. Simmons, O. Lie-Svendsen, and K. Stamnes Geophysical Institute University of Alaska Fairbanks, Alaska The Arctic is a key element in determining the radiation budget of the earth. Within the polar regions, the net radiation (incoming solar radiation minus outgoing infrared radiation) is negative. To understand the role this energy deficit plays in the overall radiation budget, one must examine the prevalent atmospheric features of the Arctic. One such feature is a persistent layer of low-altitude, stratiform clouds found over the central Arctic predominantly from April to September (Tsay et al. 1984). These Arctic stratus clouds (ASC) modulate the earth's radiation budget

210

CONTENTS Developing Alaskan Arctic  

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Developing Alaskan Arctic Developing Alaskan Arctic Potential ...........................................1 Commentary ...................................2 NETL Develops Strategic Partnership with the Alaska Center for Energy and Power ...8 Deepwater and Ultra-Deepwater Produced Water Discharge ....10 Intelligent Production System for Ultra Deepwater with Short Hop Wireless Power and Wireless Data Transfer .........................................16 Snapshots ......................................19 CONTACTS Roy Long Technology Manager Ultra-Deepwater/Offshore 304-285-4479 roy.long@netl.doe.gov Ray Boswell Technology Manager Natural Gas Technology R&D 412-386-7614 ray.boswell@netl.doe.gov Eric Smistad Technology Manager Oil Technology R&D 281-494-2619 eric.smistad@netl.doe.gov

211

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

Science Conference Proceedings (OSTI)

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.

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

2011-11-13T23:59:59.000Z

212

Microsoft PowerPoint - ARMST2006_mp.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Characterization of Arctic Characterization of Arctic Mixed-Phase Clouds Matthew D. Shupe a , Pavlos Kollias b , Ed Luke b a Cooperative Institute for Research in Environmental Sciences - University of Colorado and NOAA/ESRL/PSD and b Brookhaven National Laboratory, Atmospheric Science Division, Upton, NY Mixed-Phase Cloud Properties Cloud Occurrence. Mixed-phase clouds occur 45% +/- 10% of the time per year at the NSA site. There is a marked increase in mixed-phase cloudiness in the spring and fall transition seasons, mostly at heights below about 1 km. All mixed-phase cloud properties presented in this panel were derived from MMCR and MWR measurements at the NSA site for the time period of March 1998 through December 2004. The statistics in all plots cover this full time period. Microphysical

213

1 FEBRUARY 2004 603V A V R U S 2004 American Meteorological Society  

E-Print Network (OSTI)

to the parameterized treatment of mixed-phase microphysics. Simulated modern Arctic cloud fraction is insensitive to model biases in surface boundary conditions (SSTs and sea ice distribution), but the modeled Arctic impact on sea ice growth and the melting of snow and ice in Arctic regions (Maykut and Unter- steiner

Wisconsin at Madison, University of

214

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

ARM M-PACE Data Used to Evaluate and Improve Arctic Mixed-Phase Clouds ARM M-PACE Data Used to Evaluate and Improve Arctic Mixed-Phase Clouds Simulated in Climate Models Download a printable PDF Submitter: Xie, S., Lawrence Livermore National Laboratory Area of Research: General Circulation and Single Column Models/Parameterizations Working Group(s): Cloud Modeling Journal Reference: Xie, S, J Boyle, SA Klein, X Liu, and S Ghan. 2008. "Simulations of Arctic mixed-phase clouds in forecasts with CAM3 and AM2 for M-PACE." Journal of Geophysical Research 113, D04211, doi:10.1029/2007JD009225. Time-height cross sections of active remote sensing cloud layer (ARSCL) cloud frequency (a) and modeled cloud fraction (b) CAM3, (c) AM2, and (d) CAM3LIU at Barrow during M-PACE. The unit is %. Liquid fraction as a function of cloud height. (a) UND citation data, (b)

215

Arctic ice islands  

SciTech Connect

The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

1988-01-01T23:59:59.000Z

216

ARM - Publications: Science Team Meeting Documents  

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Evaluation of a Bulk Cloud Microphysics Model in Simulating Low-Level Evaluation of a Bulk Cloud Microphysics Model in Simulating Low-Level Arctic Mixed-Phase Clouds Using a New Single-Column Model Morison, H., Curry, J.A., and Mirocha, J., University of Colorado Eleventh Atmospheric Radiation Measurement (ARM) Science Team Meeting The MM5 NCAR/Penn State mixed-phase bulk microphysical parameterization is evaluated using a new single column model (ARCSCM) in the context of arctic low-level mixed-phase clouds. ARCSCM is developed from the Arctic Regional Climate System Model (ARCSyM). Three mixed-phase clouds over SHEBA in May 1998 are simulated using the MM5 parameterization. Liquid water path (LWP) is underpredicted by ~ 75% compared to observations for the two cases that have a significant ice content, while LWP is accurately predicted (within

217

Radiative Impacts on the Growth of a Population of Drops within Simulated Summertime Arctic Stratus  

Science Conference Proceedings (OSTI)

The impact of solar heating and infrared cooling on the growth of a population of drops is studied with two numerical modeling frameworks. An eddy-resolving model (ERM) simulation of Arctic stratus clouds is used to generate a dataset of 500 ...

Jerry Y. Harrington; Graham Feingold; William R. Cotton

2000-03-01T23:59:59.000Z

218

Cloud Chmabers  

NLE Websites -- All DOE Office Websites (Extended Search)

Video - (Requires Windows Media Player) Build your own cloud chamber - Instructions Project Contact: Tom Jordan Web Maintainer: qnet-webmaster@fnal.gov Last Update: May 31, 2011...

219

Why sequence arctic algae for alternative energy?  

NLE Websites -- All DOE Office Websites (Extended Search)

arctic algae for alternative energy? Five different protists representing different algal classes isolated from the Arctic Ocean are being investigated for adaptation to perennial...

220

Plant roots in arctic tundra  

DOE Data Explorer (OSTI)

A synthesis of the available literature on tundra root distribution and dynamics, and their role in key ecosystem processes in the Arctic.

Colleen Iversen, Victoria Sloan, Paddy Sullivan, Eugenie Euskirchen, Dave McGuire, Richard Norby, Anthony Walker, Jeff Warren, Stan Wullschleger,

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221

Cellular clouds  

Science Conference Proceedings (OSTI)

This paper progresses an analysis of what it means to be a cellular network operator and what form the ownership and control of future cellular networks may take. Alternative modes of ownership may allow for the creation of more flexible cellular networking ... Keywords: Cellular Cloud, Cellular network, Cloud Computing, Cognitive radio, DSA, LTE, MVNO, Services, Utility Cellular Network

Tim Forde; Linda Doyle

2013-03-01T23:59:59.000Z

222

NETL: Arctic Energy Office  

NLE Websites -- All DOE Office Websites (Extended Search)

Facts/Issues Facts/Issues Average South-Central natural gas consumption in 2005 was: 13.9% gas utility 20.0% power generation 54.3% industrial-LNG sales, oil refining, and fertilizer manufacturing 7.2% field operations 4.6% other Due to a lack of natural gas deliverability, the Cook Inlet fertilizer plant terminated operations in May 2008. LNG sales are increasingly curtailed during cold weather due to peak demand shortages. The LNG export license is up for renewal in 2011. Exploration must find new reserves on the order of 500 Bcf, and that will only solve the natural gas shortage until approximately 2019. Challenges Natural gas in the Arctic, until recently, has been largely overlooked. Little is known about the possible breadth of the Arctic storehouse of natural gas apart from the resource associated with the currently producing

223

Arctic Energy Office  

NLE Websites -- All DOE Office Websites (Extended Search)

O O G R A M FAC T S Strategic Center for Natural Gas & Oil CONTACTS Joel Lindstrom Arctic Energy Office National Energy Technology Laboratory 420 L Street, Suite 305 Anchorage, Alaska 99501 907-271-3618 joel.lindstrom@contr.netl.doe.gov Albert B. Yost II Sr. Management Technical Advisor Strategic Center for Natural Gas & Oil National Energy Technology Laboratory 3610 Collins Ferry Road Morgantown, WV 26507-0880 304-285-4479 albert.yost@netl.doe.gov

224

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

How Aerosols Affect Cloud Properties in Arctic Mixed-Phase Stratocumulus How Aerosols Affect Cloud Properties in Arctic Mixed-Phase Stratocumulus Download a printable PDF Submitter: McFarquhar, G., University of Illinois, Urbana Area of Research: Cloud-Aerosol-Precipitation Interactions Working Group(s): Cloud-Aerosol-Precipitation Interactions Journal Reference: Jackson RC, GM McFarquhar, AV Korolev, ME Earle, PS Liu, RP Lawson, S Brooks, M Wolde, A Laskin, and M Freer. 2012. "The dependence of ice microphysics on aerosol concentration in arctic mixed-phase stratus clouds during ISDAC and M-PACE." Journal of Geophysical Research - Atmospheres, 117, D15207, doi:10.1029/2012JD017668. Cloud mean ice crystal concentration Nice(D ā‰„ 50 micrometers) versus mean aerosol concentration (NPCASP) above cloud for all 41 vertical profiles

225

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Performance of Forecasting Models Across the North Slope of Alaska Performance of Forecasting Models Across the North Slope of Alaska During the Mixed-Phase Arctic Cloud Experiment Victor Yannuzzi, Eugene Clothiaux, Johannes Verlinde and Jerry Harrington The Pennsylvania State University Introduction The Mixed-Phase Arctic Cloud Experiment (MPACE) was conducted across the North Slope of Alaska (NSA) from September 27 through October 22, 2004. The experiment was funded by the Department of Energy (DOE)-Atmospheric Radiation Measurement (ARM) program to study the microphysics, radiative properties, thermodynamics, and life cycle of mixed-phase clouds in the Arctic. A focused set of observation stations and soundings were in place across the NSA (figure 1) where conditions could be expected to produce low-level mixed-phase clouds on

226

Evaluating cloud retrieval algorithms with the ARM BBHRP framework  

SciTech Connect

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.

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

227

Microsoft PowerPoint - ARMST2009.shupeposter.ppt [Compatibility Mode]  

NLE Websites -- All DOE Office Websites (Extended Search)

Spring and Fall Arctic Mixed-Phase Clouds: Spring and Fall Arctic Mixed-Phase Clouds: Perspectives from the surface during ISDAC and MPACE Matthew Shupe a , David Turner b , Ed Eloranta b , Pavlos Kollias c p a CIRES - University of Colorado and NOAA/ESRL, b University of Wisconsin- Madison, c McGill University Summary Cloud Boundaries -Cloud top identified using radar, cloud base identified using high spectral resolution lidar or ceilometer. Phase Classification Uses phase specific signatures from radar lidar microwave radiometer and radiosonde measurements (Shupe GRL 2007) Retrieval Methods Analysis involves 6 weeks of single-layer, stratiform, mixed-phase cloud observations from the NSA site during MPACE (Sept-Nov 2004) and ISDAC (April-May 2008) ļ¶ Similar structure and processes occur in Arctic stratiform

228

Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells (Poster)  

DOE Green Energy (OSTI)

By combining SKPM and AFM, they have developed a method to measure the local V{sub oc} distribution in mixed-phase solar cells. The results clearly show the nanocrystalline aggregation. The V{sub oc} is smaller in the nanocrystalline aggregates than in the surrounding amorphous matrix, and the transition from the low to high V{sub oc} is a gradual change. Although there are some lateral charge redistributions, a clear distinction between the amorphous and nanocrystalline regions has been observed. The current SKPM results and previous C-AFM results provide extra support for the two-diode model for explaining the carrier transport in the mixed-phase solar cells.

Jiang, C.-S.; Moutinho, H. R.; Al-Jassim, M. M.; Kazmerski, L. L.; Yan, B.; Yang, J.; Guha, S.

2006-05-01T23:59:59.000Z

229

The influence of ice nucleation mode and ice vapor growth on simulation of  

NLE Websites -- All DOE Office Websites (Extended Search)

The influence of ice nucleation mode and ice vapor growth on simulation of The influence of ice nucleation mode and ice vapor growth on simulation of arctic mixed-phase clouds Avramov, Alexander The Pennsylvania State University Category: Modeling Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic . 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. Previous studies have suggested that this longevity may be due to a paucity of ice nucleating aerosols (ice nuclei, or IN) in the Arctic. Such studies have shown that small changes in IN concentrations can cause large changes in the amount of liquid water within a mixed-phase stratus deck. We use the Regional

230

1  

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Continuous Flow Ice Thermal Diffusion Chamber Continuous Flow Ice Thermal Diffusion Chamber Measurements of Ice Nuclei in the Arctic A.J. Prenni, P.J. DeMott, and S.M. Kreidenweis Department of Atmospheric Science, Colorado State University Fort Collins, Colorado D.C. Rogers National Center for Atmospheric Research EOL/RAF Broomfield, Colorado Introduction Mixed-phase stratus clouds are ubiquitous in the Arctic and play an important role in climate in this region. However, climate and regional models have generally proven unsuccessful at simulating arctic cloudiness, particularly during the colder months. Specifically, models tend to under-predict the amount of liquid water in mixed-phase clouds. This is problematic because cloud phase can greatly impact the radiative budget. The Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted from late

231

Cloud computing beyond objects: seeding the cloud  

Science Conference Proceedings (OSTI)

Cloud computing is an emerging computing milieu which dynamically enables scalable and virtually unlimited resources. This panel will discuss emerging tools, skills and technologies that will ""seed the cloud"" - enabling improved interoperability, security, ... Keywords: cloud computing, skills, technologies, tools

Steven Fraser; Robert Biddle; Scott Jordan; Kate Keahey; Bob Marcus; E. Michael Maximilien; Dave Thomas

2009-10-01T23:59:59.000Z

232

Distribution of Local Open-Circuit Voltage on Amorphous and Nanocrystalline Mixed-Phase Si:H and SiGe:H Solar Cells: Preprint  

DOE Green Energy (OSTI)

Local open-circuit voltage (Voc) distributions on amorphous and nanocrystalline mixed-phase silicon solar cells were measured using a scanning Kelvin probe microscope (SKPM) on the p layer of an n-i-p structure without the top ITO contact. During the measurement, the sample was illuminated with a laser beam that was used for the atomic force microscopy (AFM). Therefore, the surface potential measured by SKPM is the sum of the local Voc and the difference in workfunction between the p layer and the AFM tip. Comparing the SKPM and AFM images, we find that nanocrystallites aggregate in the amorphous matrix with an aggregation size of {approx}0.5 ..mu..m in diameter, where many nanometer-size grains are clustered. The Voc distribution shows valleys in the nanocrystalline aggregation area. The transition from low to high Voc regions is a gradual change within a distance of about 1 ..mu..m. The minimum Voc value in the nanocrystalline clusters in the mixed-phase region is larger than the Voc of a nc-Si:H single-phase solar cell. These results could be due to lateral photo-charge redistribution between the two phases. We have also carried out local Voc measurements on mixed-phase SiGe:H alloy solar cells. The magnitudes of Voc in the amorphous and nanocrystalline regions are consistent with the J-V measurements.

Jiang, C.-S.; Moutinho, H. R.; Al-Jassim, M. M.; Kazmerski, L. L.; Yan, B.; Owens, J. M.; Yang, J.; Guha, S.

2006-05-01T23:59:59.000Z

233

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Minimalist Approach to Modeling Complex Arctic Clouds Minimalist Approach to Modeling Complex Arctic Clouds Download a printable PDF Submitter: Shaw, R. A., Michigan Technological University - Physics Department Area of Research: Cloud-Aerosol-Precipitation Interactions Working Group(s): Cloud Life Cycle Journal Reference: Yang F, M Ovchinnikov, and RV Shaw. 2013. "Minimalist model of ice microphysics in mixed-phase stratiform clouds." Geophysical Research Letters, 40(14), doi:10.1002/grl.50700. Nordic winter landscape. Mixed-phase stratiform clouds are common features in the Arctic environment. They contain a mix of ice and "supercooled" water that, despite the freezing temperatures, remains in liquid form. Scientists aren't sure why these clouds exist in the Arctic for long periods of time, even while steadily losing ice particles through precipitation.

234

Quantifying the Impact of Dust on Heterogeneous Ice Generation in Midlevel Supercooled Stratiform Clouds  

Science Conference Proceedings (OSTI)

Dust aerosols have been regarded as effective ice nuclei (IN), but large uncertainties regarding their efficiencies remain. Here, four years of collocated CALIPSO and CloudSat measurements are used to quantify the impact of dust on heterogeneous ice generation in midlevel supercooled stratiform clouds (MSSCs) over the ‘dust belt’. The results show that the dusty MSSCs have an up to 20% higher mixed-phase cloud occurrence, up to 8 dBZ higher mean maximum Ze (Ze_max), and up to 11.5 g/m2 higher ice water path (IWP) than similar MSSCs under background aerosol conditions. Assuming similar ice growth and fallout history in similar MSSCs, the significant differences in Ze_max between dusty and non-dusty MSSCs reflect ice particle number concentration differences. Therefore, observed Ze_max differences indicate that dust could enhance ice particle concentration in MSSCs by a factor of 2 to 6 at temperatures colder than ?12°C. The enhancements are strongly dependent on the cloud top temperature, large dust particle concentration and chemical compositions. These results imply an important role of dust particles in modifying mixed-phase cloud properties globally.

Zhang, Damao; Wang, Zhien; Heymsfield, Andrew J.; Fan, Jiwen; Liu, Dong; Zhao, Ming

2012-09-26T23:59:59.000Z

235

Review of science issues, deployment strategy, and status for the ARM north slope of Alaska-Adjacent Arctic Ocean climate research site  

SciTech Connect

Recent climate modeling results point to the Arctic as a region that is particularly sensitive to global climate change. The Arctic warming predicted by the models to result from the expected doubling of atmospheric carbon dioxide is two to three times the predicted mean global warming, and considerably greater than the warming predicted for the Antarctic. The North Slope of Alaska-Adjacent Arctic Ocean (NSA-AAO) Cloud and Radiation Testbed (CART) site of the Atmospheric Radiation Measurement (ARM) Program is designed to collect data on temperature-ice-albedo and water vapor-cloud-radiation feedbacks, which are believed to be important to the predicted enhanced warming in the Arctic. The most important scientific issues of Arctic, as well as global, significance to be addressed at the NSA-AAO CART site are discussed, and a brief overview of the current approach toward, and status of, site development is provided. ARM radiometric and remote sensing instrumentation is already deployed and taking data in the perennial Arctic ice pack as part of the SHEBA (Surface Heat Budget of the Arctic ocean) experiment. In parallel with ARM`s participation in SHEBA, the NSA-AAO facility near Barrow was formally dedicated on 1 July 1997 and began routine data collection early in 1998. This schedule permits the US Department of Energy`s ARM Program, NASA`s Arctic Cloud program, and the SHEBA program (funded primarily by the National Science Foundation and the Office of Naval Research) to be mutually supportive. In addition, location of the NSA-AAO Barrow facility on National Oceanic and Atmospheric Administration land immediately adjacent to its Climate Monitoring and Diagnostic Laboratory Barrow Observatory includes NOAA in this major interagency Arctic collaboration.

Stamnes, K. [Univ. of Alaska, Fairbanks, AK (United States). Geophysical Inst.; Ellingson, R.G. [Univ. of Maryland, College Park, MD (United States). Dept. of Meteorology; Curry, J.A. [Univ. of Colorado, Boulder, CO (United States). Dept. of Aerospace and Engineering Sciences; Walsh, J.E. [Univ. of Illinois, Urbana, IL (United States). Dept. of Atmospheric Sciences; Zak, B.D. [Sandia National Labs., Albuquerque, NM (United States)

1999-01-01T23:59:59.000Z

236

Springtime Visibility in the Arctic  

Science Conference Proceedings (OSTI)

Since the Ptarmigan flights in the 1950s, the springtime visibility reduction in the Arctic has been identified with pollution aerosol. However, observed values of the dry aerosol extinction coefficient are too small to explain the observed ...

F. G. Meyer; J. A. Curry; C. A. Brock; L. F. Radke

1991-03-01T23:59:59.000Z

237

Synoptically Driven Arctic Winter States  

Science Conference Proceedings (OSTI)

The dense network of the Surface Heat Budget of the Arctic (SHEBA) observations is used to assess relationships between winter surface and atmospheric variables as the SHEBA site came under the influence of cyclonic and anticyclonic atmospheric ...

Kirstie Stramler; Anthony D. Del Genio; William B. Rossow

2011-03-01T23:59:59.000Z

238

Introduction  

NLE Websites -- All DOE Office Websites (Extended Search)

Mixed-phase clouds, such as those found in the Arctic have presented quite a challenge to the modeling com- munity. Without modification, models have struggled to maintain the delicate balance between liquid and ice that must exist in order to maintain these clouds for ex- tended time periods, as they are observed in the atmo- sphere. In conjunction with the ARM Cloud Modeling

239

Arctic Sea ice model sensitivities.  

SciTech Connect

Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana Stefanova

2010-12-01T23:59:59.000Z

240

A 22-Year Dataset of Surface Longwave Fluxes in the Arctic  

NLE Websites -- All DOE Office Websites (Extended Search)

22-Year Dataset of Surface Longwave Fluxes 22-Year Dataset of Surface Longwave Fluxes in the Arctic J. Francis and J. Secora Institute of Marine and Coastal Sciences Rutgers University New Brunswick, New Jersey Abstract Downwelling longwave fluxes (DLFs) over the Arctic surface have been generated from 22.5 years of radiances and retrievals from the TIROS (television and infrared observation satellite) operational vertical sounder (TOVS). The flux retrieval algorithm has been validated and improved using surface- based radiation and cloud observations from the Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) site in Barrow, Alaska, and from the Surface Heat Balance of the Arctic (SHEBA) field program (1997-98) in the Beaufort Sea. The DLF product is presented on a 100 x

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Understanding Ice Formation in Arctic Mixed-Phase Boundary-Layer Clouds Understanding Ice Formation in Arctic Mixed-Phase Boundary-Layer Clouds During ISDAC Download a printable PDF Submitter: Ackerman, A., NASA - Goddard Institute for Space Studies Fridlind, A. M., NASA - Goddard Institute for Space Studies Area of Research: Cloud Distributions/Characterizations Working Group(s): Cloud-Aerosol-Precipitation Interactions Journal Reference: Avramov A, AS Ackerman, AM Fridlind, B van Diedenhoven, G Botta, K Aydin, J Verlinde, KV Alexei, W Strapp, GM McFarquhar, R Jackson, SD Brooks, A Glen, and M Wolde. 2011. "Towards ice formation closure in Arctic mixed-phase boundary layer clouds during ISDAC." Journal of Geophysical Research - Atmospheres, 116, D00T08, doi:10.1029/2011JD015910. Ice number size distributions as simulated (dendrites in red, aggregates in

242

Cloud Computing Operations Research  

Science Conference Proceedings (OSTI)

This paper argues that the cloud computing industry faces many decision problems where operations research OR could add tremendous value. To this end, we provide an OR perspective on cloud computing in three ways. First, we compare the cloud computing ... Keywords: cloud IT, cloud computing, green IT, operations research, supply chain

Ilyas Iyoob, Emrah Zarifoglu, A. B. Dieker

2013-06-01T23:59:59.000Z

243

Cloud Condensation Nuclei  

Science Conference Proceedings (OSTI)

The state of knowledge of the particles upon which liquid droplets condense to form atmospheric water clouds is presented. The realization of cloud condensation nuclei (CCN) as a distinct aerosol subset originated with the cloud microphysical ...

James G. Hudson

1993-04-01T23:59:59.000Z

244

Forecasting of Supercooled Clouds  

Science Conference Proceedings (OSTI)

Using parameterizations of cloud microphysics, a technique to forecast supercooled cloud events is suggested. This technique can be coupled on the mesoscale with a prognostic equation for cloud water to improve aircraft icing forecasts. The ...

André Tremblay; Anna Glazer; Wanda Szyrmer; George Isaac; Isztar Zawadzki

1995-07-01T23:59:59.000Z

245

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Remote Sensing and In-Situ Observations of Remote Sensing and In-Situ Observations of Arctic Mixed-Phase and Cirrus Clouds Acquired During Mixed-Phase Arctic Cloud Experiment: Atmospheric Radiation Measurement Uninhabited Aerospace Vehicle Participation G.M. McFarquhar, M. Freer, and J. Um University of Illinois Urbana, IL R. McCoy and W. Bolton Sandia National Laboratories Livermore, CA Introduction The Atmospheric Radiation Monitor (ARM) uninhabited aerospace vehicle (UAV) program aims to develop measurement techniques and instruments suitable for a new class of high altitude, long endurance UAVs while supporting the climate community with valuable data sets. Using the Scaled Composites Proteus aircraft, ARM UAV participated in Mixed-Phase Arctic Cloud Experiment (M-PACE), obtaining unique data to help understand the interaction of clouds with solar and infrared

246

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud-Top Humidity Inversions and the Maintenance of Arctic Mixed-Phase Cloud-Top Humidity Inversions and the Maintenance of Arctic Mixed-Phase Stratocumulus Submitter: Solomon, A., NOAA/ESRL/Physical Sciences Division Shupe, M., University of Colorado Area of Research: Cloud Distributions/Characterizations Working Group(s): Cloud Life Cycle Journal Reference: Solomon A, MD Shupe, O Persson, and H Morrison. 2011. "Moisture and dynamical interactions maintaining decoupled Arctic mixed-phase stratocumulus in the presence of a humidity inversion." Atmospheric Chemistry and Physics, 11, doi:10.5194/acp-11-10127-2011. Soundings of mid-day decoupled stratocumulus at Barrow, Alaska. (A) Measured 17:34Z 8 April 2008 at (71.33N,156.61W). (B) 50-m LES simulation 20Z 8 April 2008 at (71.33N,156.91W). Gray shading marks the extent of the

247

Polar Cloud and Surface Classification Using AVHRR Imagery: An Intercomparison of Methods  

Science Conference Proceedings (OSTI)

Six Advanced Very High-Resolution Radiometer local area coverage (AVHPR LAC) arctic scenes are classified into ten classes. These include water, solid sea ice, broken sea ice, snow-covered mountains, snow-free land, and five cloud types. Three ...

R. M. Welch; S. K. Sengupta; A. K. Goroch; P. Rabindra; N. Rangaraj; M. S. Navar

1992-05-01T23:59:59.000Z

248

Stratocumulus Cloud Field Reflected Fluxes: The Effect of Cloud Shape  

Science Conference Proceedings (OSTI)

Reflected fluxes are calculated for stratocumulus cloud fields as a function of sky cover, cloud aspect ratio, and cloud shape. Cloud liquid water volume is held invariant as cloud shape is varied so that the results can be utilized more ...

R. M. Welch; B. A. Wielicki

1984-11-01T23:59:59.000Z

249

The Necklace around the Arctic Arctic indigenous peoples  

E-Print Network (OSTI)

national choir). #12;The economies of the Arctic settlements invariably involve fish, oil or gas: natural in the 1002 area. This work was undertaken by a private exploration firm and funded by a group of oil exploration apparently began abruptly in A.D. 793 with an attack on Lindesfarne, an island off the NE

250

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Arctic Mixed-phase Clouds Persist with Little Help from the Local Surface Arctic Mixed-phase Clouds Persist with Little Help from the Local Surface Download a printable PDF Submitter: Shupe, M., University of Colorado Area of Research: Cloud Processes Working Group(s): Cloud Life Cycle, Cloud-Aerosol-Precipitation Interactions Journal Reference: Shupe MD, OG Persson, IM Brooks, M Tjernstrom, J Sedlar, T Mauritsen, S Sjogren, and C Leck. 2013. "Cloud and boundary layer interactions over the Arctic sea ice in late summer." Atmospheric Chemistry and Physics, 13, doi:10.5194/acp-13-9379-2013. Figure 1. Normalized profiles of (a) vertical velocity skewness and (b) variance, (c) turbulent dissipation rate, and (d) potential temperature. Black curves are all data, while red and green are for decoupled and coupled cases, respectively. Normalization is relative to the cloud top

251

Glossary Term - Cloud Chamber  

NLE Websites -- All DOE Office Websites (Extended Search)

Ceres Previous Term (Ceres) Glossary Main Index Next Term (Composition of the Earth's Atmosphere) Composition of the
Earth's Atmosphere Cloud Chamber A cloud chamber showing the...

252

Short-Term Climatic Variability of the Arctic  

Science Conference Proceedings (OSTI)

The circulation of the Arctic atmosphere undergoes large fluctuations about its monthly and annual means. The statistics of Arctic sea level pressure and temperature are evaluated in order to place Arctic atmospheric variability into the context ...

John E. Walsh; William L. Chapman

1990-02-01T23:59:59.000Z

253

Latitudinal distribution of the recent Arctic warming  

Science Conference Proceedings (OSTI)

Increasing Arctic temperature, disappearance of Arctic sea ice, melting of the Greenland ice sheet, sea level rise, increasing strength of Atlantic hurricanes are these impending climate catastrophes supported by observations? Are the recent data really unprecedented during the observational records? Our analysis of Arctic temperature records shows that the Arctic and temperatures in the 1930s and 1940s were almost as high as they are today. We argue that the current warming of the Arctic region is affected more by the multi-decadal climate variability than by an increasing concentration of carbon dioxide. Unfortunately, none of the existing coupled Atmosphere-Ocean General Circulation Models used in the IPCC 2007 cIimate change assessment is able to reproduce neither the observed 20th century Arctic cIimate variability nor the latitudinal distribution of the warming.

Chylek, Petr [Los Alamos National Laboratory; Lesins, Glen K [DALLHOUSIE UNIV.; Wang, Muyin [UNIV OF WASHINGTON

2010-12-08T23:59:59.000Z

254

Potential Oil Production from the Coastal Plain of the Arctic ...  

U.S. Energy Information Administration (EIA)

1. Overview of the Arctic National Wildlife Refuge. Background. The Arctic National Wildlife Refuge (ANWR) 1002 Area of the Alaska North Slope represents an area ...

255

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Characterization of Mixed-Phase Clouds During Characterization of Mixed-Phase Clouds During Mixed-Phase Arctic Cloud Experiment from Satellite, Ground-Based, and In-Situ Data D.A. Spangenberg Analytical Services & Materials, Inc. Hampton, Virginia P. Minnis National Aeronautics and Space Agency - Langley Research Center Hampton, Virginia S. Sun-Mack Science Applications International Corporation Hampton, Virginia M.D. Shupe Cooperative Institute for Research in Environmental Science, National Oceanic and Atmospheric Administration - Physical Sciences Division Boulder, Colorado M.R. Poellot University of North Dakota Grand Forks, North Dakota Introduction Stratiform clouds containing mainly liquid at their tops with increasing amounts of ice deep inside the cloud commonly occur over the Arctic. The ice crystals usually grow large enough to fall from the

256

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Simulating Mixed-Phase Clouds: Sensitivity to Ice Initiation Simulating Mixed-Phase Clouds: Sensitivity to Ice Initiation Download a printable PDF Submitter: Sednev, I., Lawrence Berkeley National Laboratory Menon, S., Lawrence Berkeley National Laboratory McFarquhar, G., University of Illinois, Urbana Area of Research: General Circulation and Single Column Models/Parameterizations Working Group(s): Cloud Modeling Journal Reference: I Sednev, S Menon, and G McFarquhar. 2008. "Simulating mixed-phase Arctic stratus clouds: Sensitivity to ice initiation mechanisms." Atmospheric Chemistry and Physics Discussion 8: 11755-11819. The vertical structure and radiative properties of persistent low-level Arctic clouds depend on their microphysics, and thus, estimation of the relative significance of the microphysical processes that occur in these

257

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Evaluation of a New Mixed-Phase Cloud Microphysics Parameterization with Evaluation of a New Mixed-Phase Cloud Microphysics Parameterization with SCAM, CAPT Forecasts and M-PACE Observations Download a printable PDF Submitter: Liu, X., University of Wyoming Area of Research: General Circulation and Single Column Models/Parameterizations Working Group(s): Cloud Modeling Journal Reference: Liu, X, S Xie, and SJ Ghan. 2007. "Evaluation of a new mixed-Phase cloud microphysics parameterization with the NCAR single column climate model (SCAM) and ARM M-PACE observations." Geophysical Research Letters 34, L23712, doi:10.1029/2007GL031446. Xie, S, J Boyle, SA Klein, X Liu and S Ghan. 2008. "Simulations of arctic mixed-phase clouds in forecasts with CAM3 and AM2 for M-PACE." Journal of Geophysical Research, in press.

258

The ecology of Arctic cod (Boreogadus saida) and interactions with seabirds, seals, and whales in the Canadian Arctic.  

E-Print Network (OSTI)

??This thesis investigates the foraging of Arctic cod (Boreogadus saida) and its predators during the summer in the Canadian Arctic. Findings included the identification of… (more)

Matley, Jordan

2012-01-01T23:59:59.000Z

259

Global Circuit Model with Clouds  

Science Conference Proceedings (OSTI)

Cloud data from the International Satellite Cloud Climatology Project (ISCCP) database have been introduced into the global circuit model developed by Tinsley and Zhou. Using the cloud-top pressure data and cloud type information, the authors ...

Limin Zhou; Brian A. Tinsley

2010-04-01T23:59:59.000Z

260

Arctic Inversion Strength in Climate Models  

Science Conference Proceedings (OSTI)

Recent work indicates that climate models have a positive bias in the strength of the wintertime low-level temperature inversion over the high-latitude Northern Hemisphere. It has been argued this bias leads to underestimates of the Arctic’s ...

Brian Medeiros; Clara Deser; Robert A. Tomas; Jennifer E. Kay

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Testing ice microphysics parameterizations in the NCAR Community Atmospheric Model Version 3 using Tropical Warm Pool–International Cloud Experiment data  

SciTech Connect

Cloud properties have been simulated with a new double-moment microphysics scheme under the framework of the single column version of NCAR CAM3. For comparisons, the same simulation was made with the standard single-moment microphysics scheme of CAM3. Results from both simulations were compared favorably with observations during the Tropical Warm Pool- International Cloud Experiment by US Department of Energy Atmospheric Radiation Program in terms of the temporal variation and vertical distribution of cloud fraction and cloud condensate. Major differences between the two simulations are in the magnitude and distribution of ice water content within the mixed-phase cloud during the monsoon period, though the total frozen water (snow plus ice) content is similar. The ice mass content in the mixed-phase cloud from the new scheme is larger than that from the standard scheme, and extends 2 km further downward, which are closer to observations. The dependence of the frozen water mass fraction in total condensate on temperature from the new scheme is also closer to available observations. Outgoing longwave radiation (OLR) at the top of the atmosphere (TOA) from the simulation with the new scheme is in general larger than that with the standard scheme, while the surface downward longwave radiation is similar. Sensitivity tests suggest that different treatments of the ice effective radius contribute significantly to the difference in the TOA OLR in addition to cloud water path. The deep convection process affects both TOA OLR and surface downward longwave radiation. The over-frequently-triggered deep convention process in the model is not the only mechanism for the excess middle and high level clouds. Further evaluation especially for ice cloud properties based on in-situ data is needed.

Wang, Weiguo; Liu, Xiaohong; Xie, Shaocheng; Boyle, James; McFarlane, Sally A.

2009-07-23T23:59:59.000Z

262

Cloud Computing Forum & Workshop II  

Science Conference Proceedings (OSTI)

Cloud Computing Forum & Workshop II. Purpose: On May 20, 2010, NIST hosted the first Cloud Computing Forum & Workshop. ...

2013-08-07T23:59:59.000Z

263

ISCCP Cloud Algorithm Intercomparison  

Science Conference Proceedings (OSTI)

The International Satellite Cloud Climatology Project (ISCCP) will provide a uniform global climatology of satellite-measured radiances and derive an experimental climatology of cloud radiative properties from these radiances. A pilot study to ...

W. B. Rossow; F. Mosher; E. Kinsella; A. Arking; M. Desbois; E. Harrison; P. Minnis; E. Ruprecht; G. Seze; C. Simmer; E. Smith

1985-09-01T23:59:59.000Z

264

Automated cloud resource orchestration  

Science Conference Proceedings (OSTI)

Realizing Infrastructure-as-a-Service (IaaS) cloud requires a control platform for orchestrating the provisioning, configuration, management and decommissioning of a distributed set of diverse cloud resources (i.e., compute, storage, network) serving ...

Changbin Liu / Boon Thau Loo

2012-01-01T23:59:59.000Z

265

ARM - Measurement - Cloud type  

NLE Websites -- All DOE Office Websites (Extended Search)

type ARM Data Discovery Browse Data Comments? We would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud type Cloud type such as...

266

Entrainment in Cumulus Clouds  

Science Conference Proceedings (OSTI)

Entrainment of dry air into cumulus clouds influences the development of the clouds in a major way. The many aspects of the entrainment process are examined in this paper by critically reviewing the literature from the time when investigations ...

Alan M. Blyth

1993-04-01T23:59:59.000Z

267

Clouds in Tropical Cyclones  

Science Conference Proceedings (OSTI)

Clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere. Convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts. Within ...

Robert A. Houze Jr.

2010-02-01T23:59:59.000Z

268

North Australian Cloud Lines  

Science Conference Proceedings (OSTI)

A satellite classification and climatology of propagating mesoscale cloud fines in northern Australia is presented. These cloud fines range from long, narrow lines of shallow convection to extensive deep convective squall lines with mesoscale ...

W. Drosdowsky; G. J. Holland

1987-11-01T23:59:59.000Z

269

Clouds in Tropical Cyclones  

Science Conference Proceedings (OSTI)

Clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere. Convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts. Within the ...

Robert A. Houze Jr.

2010-02-01T23:59:59.000Z

270

Phenomenological Description of Tropical Clouds Using CloudSat Cloud Classification  

Science Conference Proceedings (OSTI)

Two years of tropical oceanic cloud observations are analyzed using the operational CloudSat cloud classification product and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar. Relationships are examined between ...

Ali Behrangi; Terry Kubar; Bjorn Lambrigtsen

2012-10-01T23:59:59.000Z

271

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

Science Conference Proceedings (OSTI)

This study proposes a novel technique for computing cloud feedbacks using histograms of cloud fraction as a joint function of cloud-top pressure (CTP) and optical depth (?). These histograms were generated by the International Satellite Cloud ...

Mark D. Zelinka; Stephen A. Klein; Dennis L. Hartmann

2012-06-01T23:59:59.000Z

272

Cloud Computing at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Computing Energy Efficient Computing Exascale Computing Performance & Monitoring Tools Petascale Initiative Science Gateway Development Storage and IO Technologies Testbeds...

273

Research Highlights Sorted by Submitter  

NLE Websites -- All DOE Office Websites (Extended Search)

Submitter Submitter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A Ackerman, A. Buffering of Ice Crystal Number Concentration to Ice Nucleus Abundance above Arctic Stratus ARM To Be or Not To Be Liquid? The Challenge of Arctic Mixed-Phase Cloud Modeling ARM Tropical Rain Clouds Still a Challenge to Cloud-Resolving Models ARM ASR Understanding Ice Formation in Arctic Mixed-Phase Boundary-Layer Clouds During ISDAC ARM Ackerman, T. P. Progress in Understanding Water Vapor's Role in Models ARM Quantifying the Magnitude of Anomalous Solar Absorption ARM Shortwave Absorption in Tropical Clouds ARM Structure of Cirrus Properties and its Coupling with the State of the Large-Scale Atmosphere ARM The k-Distribution Method for a SW Radiative Transfer Model ARM Ahlgrimm, M.

274

Rope Cloud over Land  

Science Conference Proceedings (OSTI)

Satellite imagery is used to document several rope clouds over the southeastern Unites States. Surface and upper-air data are examined for one of the rope clouds and possible reasons for the development and maintenance of this type cloud line are ...

Von S. Woods

1983-03-01T23:59:59.000Z

275

User Centric Community Clouds  

Science Conference Proceedings (OSTI)

With the evolution in cloud technologies, users are becoming acquainted with seamless service provision. Nevertheless, clouds are not a user centric technology, and users become completely dependent on service providers. We propose a novel concept for ... Keywords: Cloud infrastructure, Identity management, User-centric systems

Joćo Paulo Barraca; Alfredo Matos; Rui L. Aguiar

2011-05-01T23:59:59.000Z

276

One-Particle Spectral Function and Local Density of States in a Phenomenological Mixed-Phase Model for High-Temperature Superconductors  

SciTech Connect

The dynamical properties of a recently introduced phenomenological model for high-temperature superconductors are investigated. In the clean limit, it was observed that none of the homogeneous or striped states that are induced by the model at low temperatures can reproduce the recent angle-resolved photoemission results for La{sub 2-x}Sr{sub x}CuO{sub 4} [Yoshida et al., Phys. Rev. Lett. 91, 027001 (2003)], which show a signal with two branches in the underdoped regime. On the other hand, upon including quenched disorder in the model and breaking the homogeneous state into 'patches' that are locally either superconducting or antiferromagnetic, the two-branch spectra can be reproduced. In this picture, the nodal regions are caused by d-wave superconducting clusters. Studying the density of states (DOS), a pseudogap is observed, caused by the mixture of the gapped antiferromagnetic state and a d-wave superconductor. The local DOS can be interpreted using a mixed-phase picture, similar to what is observed in tunneling experiments. It is concluded that a simple phenomenological model for cuprates can capture several of the one-particle features observed in the underdoped regime of these materials.

Mayr, Matthias [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Alvarez, Gonzalo [ORNL; Moreo, Adriana [ORNL; Dagotto, Elbio R [ORNL

2006-01-01T23:59:59.000Z

277

Turbulent molecular clouds  

E-Print Network (OSTI)

Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds trying to confront the two approaches wherever possible. After a broad presentation of the cold interstellar medium and molecular clouds, we emphasize the dynamical processes with special focus to turbulence and its impact on cloud evolution. We then review our knowledge of the velocity, density and magnetic fields. We end by openings towards new chemistry models and the links between molecular cloud structure and star--formation rates.

Hennebelle, Patrick

2012-01-01T23:59:59.000Z

278

Cloud displays for mobile users in a display cloud  

Science Conference Proceedings (OSTI)

The display cloud model allows users to select local and remote programmable displays, and add them to a user specific cloud display where the user can arrange them freely. On a cloud display, the abstraction representing remote graphical content is ... Keywords: cloud displays, display clouds, ubiquitous displays

Lars Tiede; John Markus Bjųrndalen; Otto J. Anshus

2013-02-01T23:59:59.000Z

279

Cloud Properties Working Group Low Clouds Update  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Properties Working Group Cloud Properties Working Group Low Clouds Update Low Clouds Update Jennifer Comstock Jennifer Comstock Dave Turner Dave Turner Andy Andy Vogelmann Vogelmann Instruments Instruments 90/150 GHz microwave radiometer 90/150 GHz microwave radiometer Deployed during COPS AMF Deployed during COPS AMF Exploring calibration w/ DPR ( Exploring calibration w/ DPR ( Crewell Crewell & & L L ƶ ƶ hnert hnert ) ) See COPS Breakout, Wednesday evening See COPS Breakout, Wednesday evening 183 GHz (GVR) deployed at the NSA 183 GHz (GVR) deployed at the NSA Neural network algorithm to retrieve PWV & LWP (Maria Neural network algorithm to retrieve PWV & LWP (Maria Cadeddu Cadeddu ) ) Potential VAP candidate (RPWG) Potential VAP candidate (RPWG)

280

Storm Studies in the Arctic (STAR)  

Science Conference Proceedings (OSTI)

The Storm Studies in the Arctic (STAR) network (2007–2010) conducted a major meteorological field project from 10 October–30 November 2007 and in February 2008, focused on southern Baffin Island, Nunavut, Canada—a region that experiences intense ...

John Hanesiak; Ronald Stewart; David Barber; George Liu; Justin Gilligan; Danielle Desjardins; Robyn Dyck; Shannon Fargey; Klaus Hochheim; Rebekah Martin; Peter Taylor; Sumita Biswas; Mark Gordon; Marna Albarran Melzer; Kent Moore; Robert Field; Carling Hay; Shunli Zhang; Gordon McBean; Walter Strapp; David Hudak; John Scott; Mengistu Wolde; Ron Goodson; Edward Hudson; Gabrielle Gascon; Heather Greene; William Henson; Alex Laplante

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Arctic Ocean circulation patterns revealed by GRACE  

Science Conference Proceedings (OSTI)

Measurements of ocean bottom pressure (OBP) anomalies from the satellite mission GRACE, complemented by information from two ocean models, are used to investigate the variations and distribution of the Arctic Ocean mass from 2002 through 2011. The ...

Cecilia Peralta-Ferriz; James H. Morison; John M. Wallace; Jennifer A. Bonin; Jinlun Zhang

282

Recovery mechanisms of Arctic summer sea ice  

E-Print Network (OSTI)

[1] We examine the recovery of Arctic sea ice from prescribed ice?free summer conditions in simulations of 21st century climate in an atmosphere–ocean general circulation model. We find that ice extent recovers typically within two years. The excess oceanic heat that had built up during the ice?free summer is rapidly returned to the atmosphere during the following autumn and winter, and then leaves the Arctic partly through increased longwave emission at the top of the atmosphere and partly through reduced atmospheric heat advection from lower latitudes. Oceanic heat transport does not contribute significantly to the loss of the excess heat. Our results suggest that anomalous loss of Arctic sea ice during asinglesummerisreversible,astheice–albedo feedback is alleviated by large?scale recovery mechanisms. Hence, hysteretic threshold behavior (or a “tipping point”) is unlikely to occur during the decline of Arctic summer sea?

unknown authors

2011-01-01T23:59:59.000Z

283

Derivation of Seasonal Cloud Properties at ARM-NSA from Multispectral MODIS Data  

NLE Websites -- All DOE Office Websites (Extended Search)

Derivation of Seasonal Cloud Properties at ARM-NSA Derivation of Seasonal Cloud Properties at ARM-NSA from Multispectral MODIS Data D. A. Spangenberg Analytical Services and Materials, Inc. Hampton, Virginia P. Minnis National Aeronautics and Space Administration Langley Research Center Hampton, Virginia T. Uttal National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado Q. Z. Trepte and S. S.-Mack Science Applications International Corporation Hampton, Virginia Introduction Improving climate model predictions over earth's Polar Regions requires a complete knowledge of polar cloud microphysics. Over the Arctic, there is minimal contrast between the clouds and background snow surface observed in satellite data, especially for visible wavelengths. This makes it difficult to

284

BNL | Cloud Lifecycle Infrastructure  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Life Cycle Infrastructure Cloud Life Cycle Infrastructure An important component of any long-term atmospheric measurement program is the quality control and maintenance of the datastreams from instrument systems. Further, the raw measurements from atmospheric remote sensing instrumentation are not directly useable by the majority of the scientific community. These raw measurements must be interpreted and converted to geophysical quantities that can be more readily used by a greater number of scientists to address important questions regarding the Earth's climate system. The cloud life cycle infrastructure group at BNL is led by Dr. Michael Jensen and is responsible for the development and production of cloud-related value-added products (VAPs). The cloud life cycle infrastructure group also provides mentorships for the millimeter cloud

285

BNL | Cloud Lifecycle Research  

NLE Websites -- All DOE Office Websites (Extended Search)

to be one of the major sources of uncertainty in numerical simulations of climate and weather. Improvement of the representation of clouds in numerical models requires fundamental...

286

Dispersion of Cloud Droplet Size Distributions, Cloud Parameterization...  

NLE Websites -- All DOE Office Websites (Extended Search)

National Laboratory Upton, New York Introduction Most studies of the effect of aerosols on cloud radiative properties have considered only changes in the cloud droplet...

287

Cloud Classification Before Luke Howard  

Science Conference Proceedings (OSTI)

A brief outline of the history of cloud painting prior to the first cloud classification schemes of Luke Howard and Lamarck is presented. It is shown that European painters had accurately represented most of the different cloud forms between ...

Stanely David Gedzelman

1989-04-01T23:59:59.000Z

288

Radar Reflectivity of Cumulus Clouds  

Science Conference Proceedings (OSTI)

The relationships between the radar reflectivity factor Z and significant physical cloud parameters are studied from a dataset collected with an instrumented aircraft in non- or very weakly precipitating warm clouds. The cloud droplet populations ...

Henri Sauvageot; Jilani Omar

1987-06-01T23:59:59.000Z

289

ORNL DAAC, Arctic Tundra Flux Data, February 2002  

NLE Websites -- All DOE Office Websites (Extended Search)

atmospheric fluxes in the Arctic tundra are now available on-line. The newly released data set "Arctic Tundra Flux Study in the Kuparuk River Basin (Alaska), 1994-1996" contains...

290

Is A Sleeping Climate Giant Stirring in the Arctic?  

NLE Websites -- All DOE Office Websites (Extended Search)

Is A Sleeping Climate Giant Stirring in the Arctic? Print E-mail Is a sleeping climate giant stirring in the arctic? Wednesday, June 12, 2013 Featured by NASA a member of the U.S....

291

Development of a Regional Climate Model of the Western Arctic  

Science Conference Proceedings (OSTI)

An Arctic region climate system model has been developed to simulate coupled interactions among the atmosphere, sea ice, ocean, and land surface of the western Arctic. The atmospheric formulation is based upon the NCAR regional climate model ...

Amanda H. Lynch; William L. Chapman; John E. Walsh; Gunter Weller

1995-06-01T23:59:59.000Z

292

Arctic Climate Change as Manifest in Cyclone Behavior  

Science Conference Proceedings (OSTI)

The Arctic region has exhibited dramatic changes in recent times. Many of these are intimately tied up with synoptic activity, but little research has been undertaken on how the characteristics of Arctic cyclones have changed. This paper presents ...

Ian Simmonds; Craig Burke; Kevin Keay

2008-11-01T23:59:59.000Z

293

Comments on “Current GCMs' Unrealistic Negative Feedback in the Arctic”  

Science Conference Proceedings (OSTI)

In contrast to prior studies showing a positive lapse-rate feedback associated with the Arctic inversion, Boé et al. reported that strong present-day Arctic temperature inversions are associated with stronger negative longwave feedbacks and thus ...

Felix Pithan; Thorsten Mauritsen

2013-10-01T23:59:59.000Z

294

Comments on “Current GCMs’ Unrealistic Negative Feedback in the Arctic”  

Science Conference Proceedings (OSTI)

Contrasting our expectation of a positive lapse-rate feedback associated with the Arctic inversion, Boé et al. (2009) report that strong present-day Arctic temperature inversions are associated with stronger negative longwave feedbacks and thus ...

Felix Pithan; Thorsten Mauritsen

295

Tuktoyaktuk : responsive strategies for a new Arctic urbanism  

E-Print Network (OSTI)

The Canadian Arctic is facing a set of compounding crises that will drastically impact the future of its coastal frontier. At a time when climate change is having a detrimental impact on the Arctic landscape, Northern ...

Ritchot, Pamela (Pamela Rae)

2011-01-01T23:59:59.000Z

296

The Western Arctic Linkage Experiment (WALE): Overview and Synthesis  

Science Conference Proceedings (OSTI)

The primary goal of the Western Arctic Linkage Experiment (WALE) was to better understand uncertainties of simulated hydrologic and ecosystem dynamics of the western Arctic in the context of 1) uncertainties in the data available to drive the ...

A. D. McGuire; J. E. Walsh; J. S. Kimball; J. S. Clein; S. E. Euskirchen; S. Drobot; U. C. Herzfeld; J. Maslanik; R. B. Lammers; M. A. Rawlins; C. J. Vorosmarty; T. S. Rupp; W. Wu; M. Calef

2008-06-01T23:59:59.000Z

297

The Arctic Ocean Response to the North Atlantic Oscillation  

Science Conference Proceedings (OSTI)

The climatically sensitive zone of the Arctic Ocean lies squarely within the domain of the North Atlantic oscillation (NAO), one of the most robust recurrent modes of atmospheric behavior. However, the specific response of the Arctic to annual ...

R. R. Dickson; T. J. Osborn; J. W. Hurrell; J. Meincke; J. Blindheim; B. Adlandsvik; T. Vinje; G. Alekseev; W. Maslowski

2000-08-01T23:59:59.000Z

298

Cloud Computing Forum & Workshop IV  

Science Conference Proceedings (OSTI)

Cloud Computing Forum & Workshop IV. ... NIST announces the Cloud Computing Forum & Workshop IV to be held on November 2, 3 and 4, 2011. ...

2013-08-07T23:59:59.000Z

299

BNL | Aerosol, Cloud, Precipitation Interactions  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud-Aerosol-Precipitation Interactions Cloud-Aerosol-Precipitation Interactions Atmospheric aerosols exert important "indirect effects" on clouds and climate by serving as cloud condensation nuclei (CCN) and ice nuclei that affect cloud radiative and microphysical properties. For example, an increase in CCN increases the number concentration of droplets enhances cloud albedo, and suppresses precipitation that alters cloud coverage and lifetime. However, in the case of moist and strong convective clouds, increasing aerosols may increase precipitation and enhance storm development. Although aerosol-induced indirect effects on climate are believed to have a significant impact on global climate change, estimating their impact continues to be one of the most uncertain climate forcings.

300

Cirrus Cloud Properties from a Cloud-Resolving Model Simulation Compared to Cloud Radar Observations  

Science Conference Proceedings (OSTI)

Cloud radar data collected at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains site were used to evaluate the properties of cirrus clouds that occurred in a cloud-resolving model (CRM) simulation of the 29-day summer ...

Yali Luo; Steven K. Krueger; Gerald G. Mace; Kuan-Man Xu

2003-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Studying Clouds and Aerosols with Lidar Depolarization Ratio and Backscatter Relationships  

E-Print Network (OSTI)

This dissertation consists of three parts, each devoted to a particular issue of significant importance for CALIPSO lidar observation of depolarization ratio (delta) and backscatter (gamma?) to improve current understanding of the microphysical properties of clouds and aerosols. The relationships between depolarization ratio and backscatter allow us to retrieve particle thermodynamic phase and shape and/or orientation of aerosols and clouds. The first part is devoted to the investigation of the relationships between lidar backscatter and the corresponding depolarization ratio for different cloud classifications and aerosol types. For each cloud and aerosol types, layer-averaged backscatter and backscattering depolarization ratio from the CALIPSO measurements are discussed. The present results demonstrate the unique capabilities of the CALIPSO lidar instrument for determining cloud phase and aerosols subtypes. In the second part, we evaluate the MODIS IR cloud phase with the CALIPSO cloud products. The three possible misclassifications of MODIS IR cloud phasealgorithm, which are studied by Nasiri and Kahn (2008) with radiative transfer modeling, are tested by comparing between MODIS IR phase and CALIOP observations. The current results support their hypotheses, which is that the MODIS phase algorithm may tend to classify thin cirrus clouds as water clouds or mixed phase clouds or unknown, and classify midlevel and/or mid-temperature clouds as mixed or unknown phase. In the third part, we present a comparison of mineral dust aerosol retrievals from two instruments, MODIS and CALIPSO lidar. And, we implement and evaluate a new mineral dust detection algorithm based on the analysis of thin dust radiative signature. In comparison, three commonly used visible and IR mineral dust detection algorithms, including BTD procedure, D parameter method, and multi-channel image algorithm, are evaluated with CALIPSO aerosol classification. The comparison reveals that those dust detection algorithms are not effective for optically thin dust layers, but for thick dust storm. The new algorithm using discriminant analysis with CALIPSO observation is much better in detecting thin dust layer of optical thickness between 0.1 and 2.

Cho, Hyoun-Myoung

2011-12-01T23:59:59.000Z

302

CONTRIBUTED Green Cloud Computing  

E-Print Network (OSTI)

widely dis- cussed, the shift in energy usage in a cloud computing model has received little attention cloud computing services typically operate. We consider energy consumption models of the transport of energy per bit also allows the results to be easily scaled to any usage level. We consider both public

Tucker, Rod

303

Cryptographic cloud storage  

Science Conference Proceedings (OSTI)

We consider the problem of building a secure cloud storage service on top of a public cloud infrastructure where the service provider is not completely trusted by the customer. We describe, at a high level, several architectures that combine recent and ...

Seny Kamara; Kristin Lauter

2010-01-01T23:59:59.000Z

304

ARM - Measurement - Cloud extinction  

NLE Websites -- All DOE Office Websites (Extended Search)

extinction extinction ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud extinction The removal of radiant energy from an incident beam by the process of cloud absorption and/or scattering. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments NEPHELOMETER : Nephelometer Field Campaign Instruments CEP : Cloud Extinction Probe CLDAEROSMICRO : Cloud and Aerosol Microphysical Properties EC-CONVAIR580-BULK : Environment Canada Convair 580 Bulk Parameters

305

Simulating Future Changes in Arctic and Subarctic Vegetation  

Science Conference Proceedings (OSTI)

The Arctic is a sensitive system undergoing dramatic changes related to recent warming trends. Vegetation dynamics—increases in the quantity of green vegetation and a northward migration of trees into the arctic tundra—are a component of ... Keywords: Arctic, biogeography, boreal forest, climate change, forest migration, shrub encroachment, subarctic, tundra, vegetation dynamics models

Howard E. Epstein; Jed O. Kaplan; Heike Lischke; Qin Yu

2007-07-01T23:59:59.000Z

306

ARM - 2005 ARM Science Team Meeting  

NLE Websites -- All DOE Office Websites (Extended Search)

on Climate Change (IPCC) AR4 9:15 a.m. - 10:00 a.m. Jerry Harrington: Arctic Mixed-Phase Clouds and Ice Nuclei - A Delicate Balance 10:00 a.m. - 10:45 a.m. Michael...

307

Arctic Methane, Hydrates, and Global Climate  

NLE Websites -- All DOE Office Websites (Extended Search)

Arctic Methane, Hydrates, and Global Climate Arctic Methane, Hydrates, and Global Climate Speaker(s): Matthew T. Reagan Date: March 17, 2010 - 12:00pm Location: 90-3122 Paleooceanographic evidence has been used to postulate that methane may have had a significant role in regulating past climate. However, the behavior of contemporary permafrost deposits and oceanic methane hydrate deposits subjected to rapid temperature changes, like those now occurring in the arctic and those predicted under future climate change scenarios, has only recently been investigated. A recent expedition to the west coast of Spitsbergen discovered substantial methane gas plumes exiting the seafloor at depths that correspond to the upper limit of the receding gas hydrate stability zone. It has been suggested that these plumes may be the

308

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Putting the Pieces Together Putting the Pieces Together Download a printable PDF Submitter: Fan, J., Pacific Northwest National Laboratory Area of Research: Cloud Distributions/Characterizations Working Group(s): Cloud Life Cycle Journal Reference: Fan J, S Ghan, M Ovchinnikov, X Liu, P Rasch, and A Korolev. 2011. "Representation of arctic mixed-phase clouds and the Wegener-Bergeron-Findeisen process in climate models: Perspectives from a cloud-resolving study." Journal of Geophysical Research - Atmospheres, 116, D00T07, doi:10.1029/2010JD015375. PNNL's Arctic mixed-phase cloud research was augmented with field observations from the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) in Northern Alaska. Photo courtesy of A. Korolev, Environment Canada. Vertical cross sections of (a) the vertical velocity (the contour lines)

309

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Contrasting Properties of Single-Layer and Multi-Layer Contrasting Properties of Single-Layer and Multi-Layer Arctic Stratus Sampled During the Mixed-Phase Cloud Experiment G. Zhang and G.M. McFarquhar University of Illinois Urbana, Illinois J. Verlinde The Pennsylvania State University University Park, Pennsylvania M. Poellot University of North Dakota Grand Forks, North Dakota A. Heymsfield National Center for Atmospheric Research Boulder, Colorado Introduction The microphysical properties of both single-layer and multi-layer Arctic boundary layer stratus sampled during Mixed-Phase Cloud Experiment (M-PACE) are studied. In situ measurements are used to determine how cloud properties, such as phase, size distribution and shape of cloud particles, vary as a function of normalized cloud altitude (Z

310

Cloud Computing Forensic Science Workshop  

Science Conference Proceedings (OSTI)

Cloud Computing Forensic Science Workshop. Purpose: The New Frontiers in IT and Measurement Science Rapid advances ...

2013-09-05T23:59:59.000Z

311

A marketplace for cloud resources  

Science Conference Proceedings (OSTI)

Cloud computing is an emerging paradigm aimed to offer users pay-per-use computing resources, while leaving the burden of managing the computing infrastructure to the cloud provider. We present a new programming and pricing model that gives the cloud ... Keywords: cloud computing, iaas, large-scale scheduling, pricing models, worst-case execution time

Thomas A. Henzinger; Anmol V. Singh; Vasu Singh; Thomas Wies; Damien Zufferey

2010-10-01T23:59:59.000Z

312

The Arctic and Subarctic Ocean Flux of Potential Vorticity and the Arctic Ocean Circulation  

Science Conference Proceedings (OSTI)

According to observations, the Arctic Ocean circulation beneath a shallow thermocline can be schematized by cyclonic rim currents along shelves and over ridges. In each deep basin, the circulation is also believed to be cyclonic. This circulation ...

Jiayan Yang

2005-12-01T23:59:59.000Z

313

CDIAC Cloud Data Sets  

NLE Websites -- All DOE Office Websites (Extended Search)

Period of Record A Gridded Climatology of Clouds over Land (1971-1996) and Ocean (1954-2008) from Surface Observations Worldwide (CDIAC NDP-026E) C.J. Hahn and S.G. Warren...

314

3. New Cloud Climatology  

NLE Websites -- All DOE Office Websites (Extended Search)

New Cloud Climatology New Cloud Climatology Computed for the summers (May-Au- gust) 2000 through 2004 (Berg and Kassianov 2008). Uses ARSCL VAP, Total Sky Imager, and radar wind profiler. * * Initial Evaluation of the Cumulus Potential Scheme at the ACRF SGP Site Larry Berg, William Gustafson, and Evgueni Kassianov Pacific Northwest National Laboratory 1. Motivation Shallow clouds are poorly predicted by current global and regional scale models. A new parameterization has been devel- oped that links the boundary-layer turbu- lence and the shallow clouds. 2. The CuP Parameterization The Cumulus Potential (CuP) param- eterization uses Probability Density Functions (PDFs) of temperature and moisture to represent the subgrid scale

315

ISCCP Cloud Data Products  

Science Conference Proceedings (OSTI)

The operational data collection phase of the International Satellite Cloud Climatology Project (ISCCP) began in July 1983. Since then, visible and infrared images from an international network of weather satellites have been routinely processed ...

William B. Rossow; Robert A. Schiffer

1991-01-01T23:59:59.000Z

316

Cloud Transmissivities for Canada  

Science Conference Proceedings (OSTI)

Transmissivities are determined for different cloud types using nine years of hourly irradiance measurements under overcast skies at six Canadian stations. Values for individual stations and for pooled data using irradiances uncorrected for ...

J. A. Davies; M. Abdel-Wahab; J. E. Howard

1985-03-01T23:59:59.000Z

317

Arctic Energy Technology Development Laboratory  

DOE Green Energy (OSTI)

The Arctic Energy Technology Development Laboratory was created by the University of Alaska Fairbanks in response to a congressionally mandated funding opportunity through the U.S. Department of Energy (DOE), specifically to encourage research partnerships between the university, the Alaskan energy industry, and the DOE. The enabling legislation permitted research in a broad variety of topics particularly of interest to Alaska, including providing more efficient and economical electrical power generation in rural villages, as well as research in coal, oil, and gas. The contract was managed as a cooperative research agreement, with active project monitoring and management from the DOE. In the eight years of this partnership, approximately 30 projects were funded and completed. These projects, which were selected using an industry panel of Alaskan energy industry engineers and managers, cover a wide range of topics, such as diesel engine efficiency, fuel cells, coal combustion, methane gas hydrates, heavy oil recovery, and water issues associated with ice road construction in the oil fields of the North Slope. Each project was managed as a separate DOE contract, and the final technical report for each completed project is included with this final report. The intent of this process was to address the energy research needs of Alaska and to develop research capability at the university. As such, the intent from the beginning of this process was to encourage development of partnerships and skills that would permit a transition to direct competitive funding opportunities managed from funding sources. This project has succeeded at both the individual project level and at the institutional development level, as many of the researchers at the university are currently submitting proposals to funding agencies, with some success.

Sukumar Bandopadhyay; Charles Chamberlin; Robert Chaney; Gang Chen; Godwin Chukwu; James Clough; Steve Colt; Anthony Covescek; Robert Crosby; Abhijit Dandekar; Paul Decker; Brandon Galloway; Rajive Ganguli; Catherine Hanks; Rich Haut; Kristie Hilton; Larry Hinzman; Gwen Holdman; Kristie Holland; Robert Hunter; Ron Johnson; Thomas Johnson; Doug Kame; Mikhail Kaneveskly; Tristan Kenny; Santanu Khataniar; Abhijeet Kulkami; Peter Lehman; Mary Beth Leigh; Jenn-Tai Liang; Michael Lilly; Chuen-Sen Lin; Paul Martin; Pete McGrail; Dan Miller; Debasmita Misra; Nagendra Nagabhushana; David Ogbe; Amanda Osborne; Antoinette Owen; Sharish Patil; Rocky Reifenstuhl; Doug Reynolds; Eric Robertson; Todd Schaef; Jack Schmid; Yuri Shur; Arion Tussing; Jack Walker; Katey Walter; Shannon Watson; Daniel White; Gregory White; Mark White; Richard Wies; Tom Williams; Dennis Witmer; Craig Wollard; Tao Zhu

2008-12-31T23:59:59.000Z

318

Edward Luke | BNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Edward Luke Edward Luke Advanced Applications Engineer Education Rensselaer Polytechnic Institute, B.S., Electrical Engineering Membership American Geophysical Union Areas of Interest Remote sensing of the atmosphere Cloud property retrieval algorithms Computational intelligence Pattern recognition Data fusion Radar meteorology Climate modeling Parallel/GPU computing Experience Developed a range of novel techniques for observing the microphysics and dynamics of clouds and precipitation using millimeter wavelength radars, particularly their Doppler spectra, with an emphasis on improving our detailed observational capabilities of cloud-precipitation mixtures and the formation of precipitation within cloud, including drizzling stratocumulus and Arctic mixed-phase clouds. Created algorithms for the classification of cloud types and

319

Marine Cloud Brightening  

Science Conference Proceedings (OSTI)

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could - subject to satisfactory resolution of technical and scientific problems identified herein - have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seedparticle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

Latham, John; Bower, Keith; Choularton, Tom; Coe, H.; Connolly, P.; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Philip J.; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Robert

2012-09-07T23:59:59.000Z

320

Development of Exhibit on Arctic Climate Change Called The Arctic: A Friend Acting Strangely Exhibition  

SciTech Connect

The exhibition, The Arctic: A Friend Acting Strangely, was developed at the Smithsonian Institution’s National Museum of Natural History (NMNH) as a part of the museum’s Forces of Change exhibit series on global change. It opened to the public in Spring 2006, in conjunction with another Forces of Change exhibit on the Earth’s atmosphere called Change Is in the Air. The exhibit was a 2000 square-foot presentation that explored the forces and consequences of the changing Arctic as documented by scientists and native residents alike. Native peoples of the Arctic have always lived with year-to-year fluctuations in weather and ice conditions. In recent decades, they have witnessed that the climate has become unpredictable, the land and sea unfamiliar. An elder in Arctic Canada recently described the weather as uggianaqtuq —an Inuit word that can suggest strange, unexpected behavior, sometimes described as that of “a friend acting strangely.” Scientists too have been documenting dramatic changes in the Arctic. Air temperatures have warmed over most—though not all—of the Arctic since the 1950s; Arctic precipitation may have increased by as much as 8%; seasonal melting of the Greenland Ice Sheet has increased on average by 16% since 1979; polar-orbiting satellites have measured a 15¬–20% decline in sea ice extent since the 1970s; aircraft reconnaissance and ship observations show a steady decrease in sea ice since the 1950s. In response to this warming, plant distributions have begun to shift and animals are changing their migration routes. Some of these changes may have beneficial effects while others may bring hardship or have costly implications. And, many scientists consider arctic change to be a ‘bell-weather’ for large-scale changes in other regions of the world. The exhibition included text, photos artifacts, hands-on interactives and other exhibitry that illustrated the changes being documented by indigenous people and scientists alike.

Stauffer, Barbara W.

2006-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

FORMATION OF MASSIVE MOLECULAR CLOUD CORES BY CLOUD-CLOUD COLLISION  

SciTech Connect

Recent observations of molecular clouds around rich massive star clusters including NGC 3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by cloud-cloud collision. We find that the massive molecular cloud cores have large effective Jeans mass owing to the enhancement of the magnetic field strength by shock compression and turbulence in the compressed layer. Our results predict that massive molecular cloud cores formed by the cloud-cloud collision are filamentary and threaded by magnetic fields perpendicular to the filament.

Inoue, Tsuyoshi [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa 252-5258 (Japan); Fukui, Yasuo, E-mail: inouety@phys.aoyama.ac.jp [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

2013-09-10T23:59:59.000Z

322

Snow Depth on Arctic Sea Ice  

Science Conference Proceedings (OSTI)

Snow depth and density were measured at Soviet drifting stations on multiyear Arctic sea ice. Measurements were made daily at fixed stakes at the weather station and once- or thrice-monthly at 10-m intervals on a line beginning about 500 m from ...

Stephen G. Warren; Ignatius G. Rigor; Norbert Untersteiner; Vladimir F. Radionov; Nikolay N. Bryazgin; Yevgeniy I. Aleksandrov; Roger Colony

1999-06-01T23:59:59.000Z

323

Arctic Sea Ice Albedo from AVHRR  

Science Conference Proceedings (OSTI)

The seasonal cycle of surface albedo of sea ice in the Arctic is estimated from measurements made with the Advanced Very High Resolution Radiometer (AVHRR) on the polar-orbiting satellites NOAA-10 and NOAA-11. The albedos of 145 200-km-square ...

R. W. Lindsay; D. A. Rothrock

1994-11-01T23:59:59.000Z

324

The FGGE Arctic Data Buoy Program  

Science Conference Proceedings (OSTI)

An array of about 20 drifting data buoys was established in the Arctic Ocean during the early months of 1979. The position of each buoy and the surface pressure and temperature are measured several times daily. The program expands our capability ...

A. S. Thorndike

1980-12-01T23:59:59.000Z

325

NOAAINMFS Developments Arctic Marine Research Contracts Awarded  

E-Print Network (OSTI)

on tunal porpoise, and the economic and biolog- August 1977 pacts of gas and oil exploration pre- dict the probable ecological impacts of oil and gas development on Alaska's outer continental mammals, and birds, and smaller organisms which oc- cupy the two Arctic coastal areas prior to oil and gas

326

Surface Heat Budget of the Arctic Ocean  

Science Conference Proceedings (OSTI)

A summary is presented of the Surface Heat Budget of the Arctic Ocean (SHEBA) project, with a focus on the field experiment that was conducted from October 1997 to October 1998. The primary objective of the field work was to collectocean, ice, ...

Taneil Uttal; Judith A. Curry; Miles G. Mcphee; Donald K. Perovich; Richard E. Moritz; James A. Maslanik; Peter S. Guest; Harry L. Stern; James A. Moore; Rene Turenne; Andreas Heiberg; Mark C. Serreze; Donald P. Wylie; Ola G. Persson; Clayton A. Paulson; Christopher Halle; James H. Morison; Patricia A. Wheeler; Alexander Makshtas; Harold Welch; Matthew D. Shupe; Janet M. Intrieri; Knut Stamnes; Ronald W. Lindsey; Robert Pinkel; W. Scott Pegau; Timothy P. Stanton; Thomas C. Grenfeld

2002-02-01T23:59:59.000Z

327

Cirrus Clouds. Part I: A Cirrus Cloud Model  

Science Conference Proceedings (OSTI)

A two-dimensional (x, z), time-dependent, numerical cloud model is developed for the purpose of investigating the role of various physical processes involved in the maintenance of cirriform clouds. In addition to accounting for dynamic and ...

David O'C. Starr; Stephen K. Cox

1985-12-01T23:59:59.000Z

328

On the Use of Cloud Forcing to Estimate Cloud Feedback  

Science Conference Proceedings (OSTI)

Uncertainty in cloud feedback is the leading cause of discrepancy in model predictions of climate change. The use of observed or model-simulated radiative fluxes to diagnose the effect of clouds on climate sensitivity requires an accurate ...

Brian J. Soden; Anthony J. Broccoli; Richard S. Hemler

2004-10-01T23:59:59.000Z

329

Microsoft PowerPoint - ARM STM_Shree_Mar08  

NLE Websites -- All DOE Office Websites (Extended Search)

Small Ice Crystals Small Ice Crystals In Arctic Cirrus Clouds ABSTRACT ABSTRACT Measurement of small ice crystals (D < 60 Āµm) remains an unsolved and controversial issue in the cloud physics community. Concentrations of small ice crystals are hard to measure due to shattering of crystals at probe inlets. However, these small ice crystals alter cirrus cloud radiative properties and may affect the cirrus cloud feedback in global climate models. To facilitate better estimation of small ice crystal concentrations in cirrus clouds, a new ground- based remote sensing technique has been used in combination with in situ aircraft measurements. That is, data from the Mixed-Phase Arctic Cloud Experiment (M-PACE) conducted at Barrow on the north slope of Alaska (Fall 2004) is being used to develop an Arctic

330

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Use of In-Situ Observations of Arctic Clouds to Use of In-Situ Observations of Arctic Clouds to Understand Impacts of Mixed-Phase Clouds on Single- Scattering Properties: Applications to Climate Models G. M. McFarquhar and G. Zhang University of Illinois Department of Atmospheric Sciences Urbana, Illinois S. Cober Clouds Physics Research Division Meteorological Service of Canada Downsview, Ontario Introduction Complex feedback mechanisms involving sea ice, snow cover, and clouds must be better understood and characterized before large disagreements between general circulation model (GCM) simulations of Arctic conditions can be reduced and future predictions of climate change refined. Observations obtained during the First International Satellite Cloud Climatology Project (ISCCP) Regional

331

Comparisons of CCN with Supercooled Clouds  

Science Conference Proceedings (OSTI)

More than 140 supercooled clouds were compared with corresponding out-of-cloud cloud condensation nuclei (CCN) measurements. In spite of significant differences in altitude, temperature, distances from cloud base, updraft velocity (W), ...

James G. Hudson; Stephen Noble; Vandana Jha

2010-09-01T23:59:59.000Z

332

Effects of CCN Concentrations on Stratus Clouds  

Science Conference Proceedings (OSTI)

Comparisons between cloud-base CCN concentrations and cloud droplet concentrations in stratus clouds over San Diego and 100 km out to sea showed a positive correlation. The supersaturation in these clouds, as derived from the matching of the CCN ...

James G. Hudson

1983-02-01T23:59:59.000Z

333

Microsoft PowerPoint - arm_poster_luo2007  

NLE Websites -- All DOE Office Websites (Extended Search)

Ā§ Ā§ Vertical Profiles of Microphysical Properties Ā§ Vertically Integrated Water Contents Ā§ Surface Downward Radiative Fluxes Mixed-phase Arctic Clouds Simulated by a Cloud-resolving Model: Comparison with Aircraft Observations and Sensitivity to Microphysics Parameterization Yali Luo 1,2 , Kuan-Man Xu 2 , Hugh Morrison 3 , Greg McFarquhar 4 1 National Institute of Aerospace; 2 NASA Langley Research Center; 3 National Center for Atmospheric Research; 4 University of Illinois at Urbana-Champaign Objectives Ā§ To evaluate the ability of a cloud-resolving model (CRM) to simulate mixed-phase stratiform (MPS) Arctic clouds; Ā§ To explore the sensitivity of the CRM simulated MPS to microphysics parameterization. Case and Evaluation Data Ā§ Case Description: In the period 9-14 October, 2004,

334

ETSI CLOUD - initial standardization requirements for cloud services  

Science Conference Proceedings (OSTI)

While the technological basis for cloud services is relatively mature, the development of the market is still at an early stage. There is considerable potential, but also a number of widely held concerns which are inhibiting mainstream adoption of cloud ... Keywords: ETSI, cloud services, standardization

Karsten Oberle; Mike Fisher

2010-08-01T23:59:59.000Z

335

More Observations of Small Funnel Clouds and Other Tubular Clouds  

Science Conference Proceedings (OSTI)

In this brief contribution, photographic documentation is provided of a variety of small, tubular-shaped clouds and of a small funnel cloud pendant from a convective cloud that appears to have been modified by flow over high-altitude mountains in ...

Howard B. Bluestein

2005-12-01T23:59:59.000Z

336

Observations of Cloud-Top Entrainment in Marine Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

Measurements of the thermodynamic and dynamic properties of entrainment events in marine stratocumulus are used to explain why cloud-top entrainment instability may not lead to the breakup of the clouds and to define the role of cloud-top ...

Qing Wang; Bruce A. Albrecht

1994-06-01T23:59:59.000Z

337

The Magellan Final Report on Cloud Computing  

E-Print Network (OSTI)

resources. 1. Finding Tropical Cyclones on a Cloud Computing2010 2. Finding Tropical Cyclones on Clouds, D. Hasenkamp

Coghlan, Susan

2013-01-01T23:59:59.000Z

338

Internet ware cloud computing :Challenges  

E-Print Network (OSTI)

After decades of engineering development and infrastructural investment, Internet connections have become commodity product in many countries, and Internet scale "cloud computing" has started to compete with traditional software business through its technological advantages and economy of scale. Cloud computing is a promising enabling technology of Internet ware Cloud Computing is termed as the next big thing in the modern corporate world. Apart from the present day software and technologies, cloud computing will have a growing impact on enterprise IT and business activities in many large organizations. This paper provides an insight to cloud computing, its impacts and discusses various issues that business organizations face while implementing cloud computing. Further, it recommends various strategies that organizations need to adopt while migrating to cloud computing. The purpose of this paper is to develop an understanding of cloud computing in the modern world and its impact on organizations and businesse...

Qamar, S; Singh, Mrityunjay

2010-01-01T23:59:59.000Z

339

Mechanisms of Banner Cloud Formation  

Science Conference Proceedings (OSTI)

Banner clouds are clouds in the lee of steep mountains or sharp ridges. Their formation has previously been hypothesized as due to three different mechanisms: (i) vertical uplift in a lee vortex (which has a horizontal axis), (ii) adiabatic ...

Matthias Voigt; Volkmar Wirth

2013-11-01T23:59:59.000Z

340

Remote Sensing of Cloud Parameters  

Science Conference Proceedings (OSTI)

Day and night mapping of the global distributions of the horizontal cloud covers and the corresponding cloud-top pressure levels are derived from the same set of infrared radiance data used to retrieve clear-column temperature profiles. General ...

Moustafa T. Chahine

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

A Computer for the Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

Computer for the Clouds A Computer for the Clouds August 1, 2008 By PHILIP E. ROSS Columnist IEEE Spectrum: Inside Technology In May an IBM-built supercomputer called Roadrunner...

342

Supersaturation Intermittency in Turbulent Clouds  

Science Conference Proceedings (OSTI)

It is hypothesized that bursts of high supersaturation are produced in turbulent, convective clouds through interactions between cloud droplets and the small-scale structure of atmospheric turbulence. This hypothesis is based on the observation ...

Raymond A. Shaw

2000-10-01T23:59:59.000Z

343

Ash cloud aviation advisories  

SciTech Connect

During the recent (12--22 June 1991) Mount Pinatubo volcano eruptions, the US Air Force Global Weather Central (AFGWC) requested assistance of the US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) in creating volcanic ash cloud aviation advisories for the region of the Philippine Islands. Through application of its three-dimensional material transport and diffusion models using AFGWC meteorological analysis and forecast wind fields ARAC developed extensive analysis and 12-hourly forecast ash cloud position advisories extending to 48 hours for a period of five days. The advisories consisted of ``relative`` ash cloud concentrations in ten layers (surface-5,000 feet, 5,000--10,000 feet and every 10,000 feet to 90,000 feet). The ash was represented as a log-normal size distribution of 10--200 {mu}m diameter solid particles. Size-dependent ``ashfall`` was simulated over time as the eruption clouds dispersed. Except for an internal experimental attempt to model one of the Mount Redoubt, Alaska, eruptions (12/89), ARAC had no prior experience in modeling volcanic eruption ash hazards. For the cataclysmic eruption of 15--16 June, the complex three-dimensional atmospheric structure of the region produced dramatically divergent ash cloud patterns. The large eruptions (> 7--10 km) produced ash plume clouds with strong westward transport over the South China Sea, Southeast Asia, India and beyond. The low-level eruptions (< 7 km) and quasi-steady-state venting produced a plume which generally dispersed to the north and east throughout the support period. Modeling the sequence of eruptions presented a unique challenge. Although the initial approach proved viable, further refinement is necessary and possible. A distinct need exists to quantify eruptions consistently such that ``relative`` ash concentrations relate to specific aviation hazard categories.

Sullivan, T.J.; Ellis, J.S. [Lawrence Livermore National Lab., CA (United States); Schalk, W.W.; Nasstrom, J.S. [EG and G, Inc., Pleasanton, CA (United States)

1992-06-25T23:59:59.000Z

344

NIST Cloud Computing Related Publications  

Science Conference Proceedings (OSTI)

... Challenging Security Requirements for US Government Cloud Computing Adoption", December 2012 C. Dabrowski and K. Mills, "VM Leakage and ...

2013-07-31T23:59:59.000Z

345

Polyethylene Pipe Failure in the Arctic - Programmaster.org  

Science Conference Proceedings (OSTI)

In the current study, a new high density polyethylene (HDPE) pipe in the Arctic region of ... Heat Tint Effects on General Corrosion Resistance of Stainless Steels .

346

Potential Oil Production from the Coastal Plain of the Arctic...  

U.S. Energy Information Administration (EIA) Indexed Site

2. Analysis Discussion Resource Assessment The USGS most recent assessment of oil and gas resources of ANWR Coastal Plain (The Oil and Gas Resource Potential of the Arctic...

347

Potential Oil Production from the Coastal Plain of the Arctic...  

U.S. Energy Information Administration (EIA) Indexed Site

Potential Oil Production from the Coastal Plain of the Arctic National Wildlife Refuge: Updated Assessment Glossary ANILCA: Alaska National Interest Lands Conservation Act ANS:...

348

Contract RBAC in cloud computing  

Science Conference Proceedings (OSTI)

Cloud computing is a fast growing field, which is arguably a new computing paradigm. In cloud computing, computing resources are provided as services over the Internet and users can access resources based on their payments. The issue of access control ... Keywords: Cloud computing, Contract, Contract RBAC, Datacenter, RBAC

Hsing-Chung (Jack) Chen, Marsha Anjanette Violetta, Cheng-Ying Yang

2013-11-01T23:59:59.000Z

349

Improving Utilization of Infrastructure Clouds  

Science Conference Proceedings (OSTI)

A key advantage of infrastructure-as-a-service (IaaS) clouds is providing users on-demand access to resources. To provide on-demand access, however, cloud providers must either significantly overprovision their infrastructure (and pay a high price for ... Keywords: Cloud Computing, Infrastructure-as-a-Service, High Throughput Computing

Paul Marshall; Kate Keahey; Tim Freeman

2011-05-01T23:59:59.000Z

350

Parameterizing Vertically Coherent Cloud Distributions  

Science Conference Proceedings (OSTI)

A parameterization for specifying subgrid-scale cloud distributions in atmospheric models is developed. The fractional area of a grid-scale column in which clouds from two levels overlap (i.e., the cloud overlap probability) is described in terms ...

John W. Bergman; Philip J. Rasch

2002-07-01T23:59:59.000Z

351

Climate-derived tensions in Arctic security.  

Science Conference Proceedings (OSTI)

Globally, there is no lack of security threats. Many of them demand priority engagement and there can never be adequate resources to address all threats. In this context, climate is just another aspect of global security and the Arctic just another region. In light of physical and budgetary constraints, new security needs must be integrated and prioritized with existing ones. This discussion approaches the security impacts of climate from that perspective, starting with the broad security picture and establishing how climate may affect it. This method provides a different view from one that starts with climate and projects it, in isolation, as the source of a hypothetical security burden. That said, the Arctic does appear to present high-priority security challenges. Uncertainty in the timing of an ice-free Arctic affects how quickly it will become a security priority. Uncertainty in the emergent extreme and variable weather conditions will determine the difficulty (cost) of maintaining adequate security (order) in the area. The resolution of sovereignty boundaries affects the ability to enforce security measures, and the U.S. will most probably need a military presence to back-up negotiated sovereignty agreements. Without additional global warming, technology already allows the Arctic to become a strategic link in the global supply chain, possibly with northern Russia as its main hub. Additionally, the multinational corporations reaping the economic bounty may affect security tensions more than nation-states themselves. Countries will depend ever more heavily on the global supply chains. China has particular needs to protect its trade flows. In matters of security, nation-state and multinational-corporate interests will become heavily intertwined.

Backus, George A.; Strickland, James Hassler

2008-09-01T23:59:59.000Z

352

Spatial and Temporal Variability of Aerosol Particles in Arctic Spring  

SciTech Connect

The objective of this work is to investigate the variability in the particle number concentration that may affect climate change assessment for Arctic regions. The Indirect and Semi-Direct Aerosol Campaign (ISDAC) was conducted in April 2008, in the vicinities of Fairbanks and Barrow, Alaska. Measurements of particle number concentrations and size distributions were conducted using a Passive Cavity Aerosol Spectrometer Probe (PCASP-100X) mounted under the Convair-580 aircraft wing. Total number concentration of particles (Na) with diameters in the range 0.12-3 ?m was determined for polluted and clean air masses during times when the air was free of clouds and/or precipitation. Variability in Na was considered for both vertical profiles and constant altitude (horizontal) flight legs. This variability can have important implications for estimates of particle properties used in global climate model (GCM) simulations. When aerosol particle layers were encountered, Na rapidly increased from 25 cm-3 up to 550 cm-3 within relatively clean air masses, and reached up to 2200 cm-3 within polluted air masses, dominated by biomass burning pollution. When averaging Na over different distance scales, it was found that Na=140 cm-3 represent an average value for the majority of the encountered clean cases; while Na=720 cm-3 is a mean for polluted cases dominated by biomass burning plumes. These estimates, however, would not capture the details of particle layers encountered during most of the flights. Average aerosol particle characteristics can be difficult to interpret, especially during polluted cases, due to small-scale spatial and temporal variability.

Shantz, Nicole C.; Gultepe, Ismail; Liu, Peter; Earle, Michael; Zelenyuk, Alla

2012-10-01T23:59:59.000Z

353

A Smooth Cloud Model  

Science Conference Proceedings (OSTI)

In this paper a large-eddy “smooth” cloud (SC) model will be presented with smooth implying that the entire model converges under a Newton-based solution procedure or that time scales within the SC model are being resolved. Besides ensuring that ...

J. M. Reisner; C. A. Jeffery

2009-06-01T23:59:59.000Z

354

Cumulus Cloud Properties Derived Using Landsat Satellite Data  

Science Conference Proceedings (OSTI)

Landsat Multispectral Scanner (MSS) digital data are used to remotely sense cumulus cloud properties such as cloud fraction and cloud reflectance, along with the distribution of cloud number and cloud fraction as a function of cloud size. The ...

Bruce A. Wielicki; Ronald M. Welch

1986-03-01T23:59:59.000Z

355

Session Papers North Slope of Alaska and Adjacent Arctic Ocean...  

NLE Websites -- All DOE Office Websites (Extended Search)

over the NSAAAO throughout the year, it is well positioned to address these issues. Ice Phase Clouds Ice phase clouds are important globally, not just regionally. However, at...

356

The convective structures associated with cloud-to-ground lightning in TOGA COARE Mesoscale Convective Systems  

E-Print Network (OSTI)

The TOGA COARE experiment was carried out in the western Pacific warm pool region from November 1992 through February 1993. Data from TOGA COARE provide the opportunity for comprehensive studies of tropical oceanic convection. This study seeks to understand more about the structures of tropical mesoscale convective systems in relation to their lightning activity and cold cloud area. The properties of convective cores within the MCSs, as well as their infrared (IR) cloud top temperatures are related to cloud-to-ground lightning. IR and lightning time histories for each case are compared, and the cases ranked by mean flashes per 10000 km2. For selected cases, radar/lightning overlays and vertical profiles of maximum radar reflectivities (VPRRs) are shown in order to describe the convective structures of cells that produced lightning, and also cells that did not produce lightning. IR cloud-top temperature and lightning histories indicate the highly variable nature of the TOGA COARE MCSs. Some MCSs which have very cold cloud-top temperatures have little or no lightning. When a system did produce lightning, more flashes generally occurred during its growth phase. Overall, IR measurements seem to be a poor indicator of lightning due to the lack of a clear relationship between the size of cold cloud-top area and cloud-to-ground flashes. The overall flash rates of the TOGA COARE MCSs support previous work which showed that tropical oceanic convection has an order of magnitude less cloud-to-ground lightning than continental convection. In fact, the highest flash rate for the 13 cases was less than the weakest continental case in a Texas MCS study (Toracinta et al. 1995). Examination of individual VPRR and of all convective VPRR from the 13 cases indicate a pronounced difference between lightning producing and non-lightning producing cells. Lightning producing convective cells have higher radar reflectivity in the 5.0- 8.0 km layer, and a slower decrease with height, both observations indicating larger ice particles in the mixed phase region between 00 C and-200 C.

Restivo, Michael Edward

1995-01-01T23:59:59.000Z

357

Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications  

E-Print Network (OSTI)

or phase space. In this work we con- sider the trajectory of sea ice in the ice thickness phase space. We175 Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications Geophysical Is the Trajectory of Arctic Sea Ice? Harry L. Stern and Ronald W. Lindsay Polar Science Center, Applied Physics

Lindsay, Ron

358

Near-Inertial Wave Propagation in the Western Arctic  

Science Conference Proceedings (OSTI)

From October 1997 through October 1998, the Surface Heat Budget of the Arctic (SHEBA) ice camp drifted across the western Arctic Ocean, from the central Canada Basin over the Northwind Ridge and across the Chukchi Cap. During much of this period, ...

Robert Pinkel

2005-05-01T23:59:59.000Z

359

Forecast Calls for Better Models: Examining the Core  

NLE Websites -- All DOE Office Websites (Extended Search)

Forecast Calls for Better Models: Examining the Core Forecast Calls for Better Models: Examining the Core Components of Arctic Clouds to Clear Their Influence on Climate For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight Predicting how atmospheric aerosols influence cloud formation and the resulting feedback to climate is a challenge that limits the accuracy of atmospheric models. This is especially true in the Arctic, where mixed-phase (both ice- and liquid-based) clouds are frequently observed, but the processes that determine their composition are poorly understood. To obtain a closer look at what makes up Arctic clouds, scientists characterized cloud droplets and ice crystals collected at the North Slope of Alaska as part of the Indirect and Semi-Direct Aerosol Campaign (ISDAC) field study

360

Semantic-based web service discovery and chaining for building an Arctic spatial data infrastructure  

Science Conference Proceedings (OSTI)

Increasing interests in a global environment and climate change have led to studies focused on the changes in the multinational Arctic region. To facilitate Arctic research, a spatial data infrastructure (SDI), where Arctic data, information, and services ... Keywords: Arctic, Crawler, Hydrology, Knowledge base, Ontology, SDI, Semantic, Service chain

W. Li; C. Yang; D. Nebert; R. Raskin; P. Houser; H. Wu; Z. Li

2011-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Statistical cloud coverage as a function of cloud optical thickness  

Science Conference Proceedings (OSTI)

The time-averaged, daylight fractional statistical cloud coverages as a function of cloud optical thickness and selected values of cloud transmission were determined for various geographic areas using D1 data from the International Satellite Cloud Climatology Project (ISCCP). The regions of interest chosen for this report are: global earth, global sea, global land, global coast, and the six 30{degree}-latitude bands over sea, over land, and over coast with longitude 0{degree}--360{degree}. This statistical information is deduced from data determined from satellite measurements of terrestrial, atmospheric and cloud properties by the International Satellite Cloud Climatology Project. In particular the results are based on the ISCCP D1 data base.

Brower, K.L.

1998-07-01T23:59:59.000Z

362

Hupmobile cloud chamber parameters  

SciTech Connect

The accompanying table lists the presently selected parameters for the twelve cloud chambers. The chambers are numbered consecutively from 4 through 15 as they are lined up in the bunker. The lowest number is closest to the source. All except the first chamber have some thin metal filters to attenuate the flux and harden the spectrum. Cloud chambers 10, 12, and 14 are shielded by a collimator with about 200 pinholes in it. The flux in these chambers is attenuated by the ratio of the pinhole area to total beam area which is a factor of 50. Various gases and gas pressures are used to obtain suitable track lengths and interaction cross sections. Neon, argon, and krypton are used to obtain photo electrons. Hydrogen is used to obtain Compton electrons.

Hansen, N. E.

1967-09-28T23:59:59.000Z

363

An Automated Cirrus Cloud Detection Method for a Ground-Based Cloud Image  

Science Conference Proceedings (OSTI)

Cloud detection is a basic research for achieving cloud-cover state and other cloud characteristics. Because of the influence of sunlight, the brightness of sky background on the ground-based cloud image is usually nonuniform, which increases the ...

Jun Yang; Weitao Lu; Ying Ma; Wen Yao

2012-04-01T23:59:59.000Z

364

A Cloud-Resolving Model with an Adaptive Vertical Grid for Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

Accurate cloud-resolving model simulations of cloud cover and cloud water content for boundary layer clouds are difficult to achieve without vertical grid spacing well below 100 m, especially for inversion-topped stratocumulus. The need for fine ...

Roger Marchand; Thomas Ackerman

2011-05-01T23:59:59.000Z

365

Preliminary definition of Barstow standard cloud model  

DOE Green Energy (OSTI)

The motion of cloud shadows across a collector field for a central receiver solar power plant can affect the design of such a facility. Cloud models were developed to be used for basis of design in technology areas. The first effect, that of the temperature gradient, is simulated by postulating the worst case cloud situation. The cyclic effects require realistic cloud shadow time histories for simulation. Cloud shadow models were developed to determine probable cloud type, the cloud area and shape, cloud velocity and cloud-to-cloud spacing. The probability of cloud occurrence is estimated. A collector field computer program is run to determine the effect of cloud variables on collector field power delivery capability. Recommendation of cloud models to be used for basis of design are then made.

None

1978-04-05T23:59:59.000Z

366

CloudCast: Cloud Computing for Short-Term Weather Forecasts  

Science Conference Proceedings (OSTI)

CloudCast provides clients with personalized short-term weather forecasts based on their current location using cloud services

Dilip Kumar Krishnappa; David Irwin; Eric Lyons; Michael Zink

2013-01-01T23:59:59.000Z

367

Cumulus Clouds and Reflected Sunlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Cumulus Clouds and Reflected Sunlight Cumulus Clouds and Reflected Sunlight from Landsat ETM+ G. Wen and L. Oreopoulos National Aeronautics and Space Administration Goddard Space Flight Center University of Maryland Baltimore County Joint Center of Earth System Technology Greenbelt, Maryland R. F. Cahalan and S. C. Tsay National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt, Maryland Introduction Cumulus clouds attenuate solar radiation casting shows on the ground. Cumulus clouds can also enhance solar radiation in the clear region nearby. The enhancement of down-welling solar radiation has been observed at the ground level in the clear region near cumulus clouds (Mims and Frederick 1994). The additional diffuse radiation source from cumulus clouds makes the clear gaps appear to be

368

Size of Cloud from Shadow  

NLE Websites -- All DOE Office Websites (Extended Search)

Size of Cloud from Shadow Size of Cloud from Shadow Name: mike Status: other Grade: other Location: N/A Country: USA Date: Summer 2011 Question: I see a cloud and I see its shadow in a field - knowing high sun angles - is there a way of telling how far away the cloud is or how big? - I am thinking if the shadow is 30' wide and the sun is at 2:00 pm- ? Replies: Hi Mike, Try this, draw a small circle representing the Sun. Somewhere below this circle and maybe to the right, draw an oblong, make this oblong bigger than the circle. Now connect the leftmost edge of the circle with the leftmost edge of the oblong with a straight line. Do the same for the rightmost edges. The oblong now represent the shadow of a cloud on the ground, and the lines represent the rays of the sun passing along the edges of the cloud.

369

ARM - Measurement - Total cloud water  

NLE Websites -- All DOE Office Websites (Extended Search)

cloud water cloud water ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Total cloud water The total concentration (mass/vol) of ice and liquid water particles in a cloud; this includes condensed water content (CWC). Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. External Instruments NCEPGFS : National Centers for Environment Prediction Global Forecast System Field Campaign Instruments CSI : Cloud Spectrometer and Impactor PDI : Phase Doppler Interferometer

370

ARM - Measurement - Cloud droplet size  

NLE Websites -- All DOE Office Websites (Extended Search)

droplet size droplet size ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud droplet size Linear size (e.g. radius or diameter) of a cloud particle Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. Field Campaign Instruments CPI : Cloud Particle Imager CVI-AIR : Counterflow Virtual Impactor MIRAI : JAMSTEC Research Vessel Mirai PDI : Phase Doppler Interferometer UAV-PROTEUS-MICRO : Proteus Cloud Microphysics Instruments SPEC-CPI : Stratton Park Engineering Company - Cloud particle imager

371

Total aerosol effect: forcing or radiative flux perturbation?  

E-Print Network (OSTI)

heterogeneous ice nucleation in mixed-phase clouds, Environ.interactions with mixed-phase and ice clouds can be comparedice nuclei for the indirect aerosol effect on stratiform mixed-phase

Lohmann, Ulrike

2010-01-01T23:59:59.000Z

372

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

E-Print Network (OSTI)

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

Stoffelen, Ad

373

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Lidar-Based Retrievals of the Microphysical Properties of Lidar-Based Retrievals of the Microphysical Properties of Mixed-Phase Arctic Stratus Clouds and Precipitation G. de Boer and E. Eloranta The University of Wisconsin Madison, Wisconsin Abstract The University of Wisconsin Arctic High Spectral Resolution Lidar has acquired months of continuous measurements in two high Arctic locations. These measurements have been combined with those taken by a National Oceanic and Atmospheric Administration - Environmental Technological Laboratory millimeter wave cloud radar to establish a long-range data set of cloud microphysical property retrievals. These properties include effective particle size, number density, and water content. Examples from this data set for arctic stratus are reviewed here, along with the methodology used in the retrievals.

374

Droplet Number Prediction in the NCAR Community Atmosphere Model Steven Ghan Pacific Northwest National Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Semi-Direct Aerosol Campaign: Semi-Direct Aerosol Campaign: The Influence of Arctic Aerosol on Clouds G. McFarquhar, S. Ghan, J. Verlinde, B. Schmid, J. Tomlinson, J. Hubbe, D. Ronfeld, S. Brooks, D. Collins, D. Cziczo, M. Dubey, M. Gilles, I. Gultepe, G. Kok, A. Korolev, A. Laskin, P. Lawson, P. Liu, C. Mazzoleni, A. Macdonald, R. Moffet, W. Strapp, M. Wolde, A. Zelenyuk, C. Flynn, D. Lubin, M. Shupe, D. Turner M. Ovchinnikov, S. Xie, H. Morrison & A. Soloman Key Issues 1. How do properties of arctic aerosol in April differ from those measured in October during the Mixed Phase Arctic Cloud Experiment (M-PACE)? 2. To what extent do different properties of arctic aerosol during April produce differences in cloud microphysical and macrophysical properties and the surface energy balance?

375

TC_CLOUD_REGIME.cdr  

NLE Websites -- All DOE Office Websites (Extended Search)

Tropical cloud properties as a function of regime Regimes? Monsoon versus Break * Different synoptic vertical velocity profiles - Changes convective inhibition, corresponding...

376

Service Availability in Cloud Computing.  

E-Print Network (OSTI)

?? Cloud computing provides access to on-demand computing resources and storage space, whereby applications and data are hosted with data centers managed by third parties,… (more)

Adegoke, Adekunle

2013-01-01T23:59:59.000Z

377

China Total Cloud Amount Trends  

NLE Websites -- All DOE Office Websites (Extended Search)

Trends in Total Cloud Amount Over China DOI: 10.3334CDIACcli.008 data Data image Graphics Investigator Dale P. Kaiser Carbon Dioxide Information Analysis Center, Environmental...

378

Microsoft PowerPoint - ARMST2007_mp.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Motions in Arctic Mixed-Phase Stratus Motions in Arctic Mixed-Phase Stratus Matthew D. Shupe a , Pavlos Kollias b , Ola Persson a , Ed Luke b Greg McFarquhar c , Michael Poellot d , Edwin Eloranta e a CIRES - University of Colorado and NOAA/ESRL/PSD, b Brookhaven National Laboratory, c University of Illinois, d University of North Dakota, e University of Wisonsin Mixed-Phase Cloud Properties Air Motions from Doppler Spectra Funded by: ARM Grant DE-FG02-05ER63965 Summary A Conceptual Model relating air motions and microphysics A Doppler Spectrum Small liquid droplets trace vertical air motions Liquid Droplets Ice Particles Correction for spectral broadening W Aircraft comparisons during M-PACE Vertical velocity (W) and turbulent dissipation rates (Īµ). Retrieval data are mean (symbol) and middle 90% of data (line)

379

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Cloud Properties and Heating Cloud Properties and Heating Rates in Tropical Cloud Systems Jennifer Comstock and Sally McFarlane Pacific Northwest National Laboratory Alain Protat Centre for Australian Weather and Climate Research Motivation Cloud properties retrievals Cloud process understanding Cloud Radiative forcing and heating rates Model evaluation on many scales (LES, CRM, SCM...) Quantified uncertainties are needed... 2 Retrieval Algorithm Evaluation within CPWG Past intercomparisons CLOWD - Clouds with Low Optical Water Depths (Turner et al. 2007) Ice Clouds - (Comstock et al. 2007) One retrieval does not fit all Present algorithm evaluation BBHRP Ice Cloud Retrievals at SGP - Microbase (Dunn, Jensen, Mace, Marchand) Arctic mixed phase clouds - BBHRP (Shupe, Turner) CLOWD - BBHRP Pt. Reyes AMF deployment

380

Cloud Microphysical Relationships in California Marine Stratus  

Science Conference Proceedings (OSTI)

Cloud microphysical measurements off the southern California coast are presented and compared with in situ airborne measurements of cloud condensation nuclei (CCN) spectra. Large-scale variations in cloud droplet concentrations were due to CCN ...

James G. Hudson; Gunilla Svensson

1995-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Statistical Description of Radiation Transfer in Clouds  

Science Conference Proceedings (OSTI)

The statistical characteristics of simulated cloud fields constructed based on Poisson point fluxes are studied. The input parameters of mathematical models of cloudiness include the cloud fraction and the mean horizontal size of clouds ...

Georgi A. Titov

1990-01-01T23:59:59.000Z

382

Radiative Effects of Cloud-Type Variations  

Science Conference Proceedings (OSTI)

Radiative flux changes induced by the occurrence of different cloud types are investigated using International Satellite Cloud Climatology Project cloud data and a refined radiative transfer model from National Aeronautics and Space ...

Ting Chen; William B. Rossow; Yuanchong Zhang

2000-01-01T23:59:59.000Z

383

CALIPSO/CALIOP Cloud Phase Discrimination Algorithm  

Science Conference Proceedings (OSTI)

The current cloud thermodynamic phase discrimination by Cloud-Aerosol Lidar Pathfinder Satellite Observations (CALIPSO) is based on the depolarization of backscattered light measured by its lidar [Cloud-Aerosol Lidar with Orthogonal Polarization (...

Yongxiang Hu; David Winker; Mark Vaughan; Bing Lin; Ali Omar; Charles Trepte; David Flittner; Ping Yang; Shaima L. Nasiri; Bryan Baum; Robert Holz; Wenbo Sun; Zhaoyan Liu; Zhien Wang; Stuart Young; Knut Stamnes; Jianping Huang; Ralph Kuehn

2009-11-01T23:59:59.000Z

384

The Visualization of Cloud Droplet Spectra  

Science Conference Proceedings (OSTI)

This paper draws attention to the use of readily available, wire cage graphics for inspecting cloud droplet spectra measured using a Forward Light-Scattering Spectrometer Probe. The high resolution cloud droplet spectra from two different clouds ...

Robert R. Czys

1989-02-01T23:59:59.000Z

385

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

386

Simulation of Arctic Clouds in Climate Models | U.S. DOE Office...  

NLE Websites -- All DOE Office Websites (Extended Search)

News In the News In Focus Presentations & Testimony Recovery Act About Organization Budget Field Offices Federal Advisory Committees History Scientific and Technical...

387

NIST Joint Cloud and Big Data Workshop  

Science Conference Proceedings (OSTI)

NIST Joint Cloud and Big Data Workshop. Purpose: ... The second and third days of the workshop focused on the intersection of Cloud and Big Data. ...

2013-01-31T23:59:59.000Z

388

6.1 Cloud Management Broker  

Science Conference Proceedings (OSTI)

... the cloud-management-broker programming or human interface, and ... broker notifies cloud-user with error specifics or ... Transient errors can be retried ...

2010-11-02T23:59:59.000Z

389

Radiative Effects of Cloud Inhomogeneity and  

NLE Websites -- All DOE Office Websites (Extended Search)

cloud-overlap assumptions and optical property approximations (Del Genio et al. 1996; Fowler and Randall 1996; Liang and Wang 1997). While GCMs require convection and cloud...

390

Cloud Computing Towards Technological Convergence  

Science Conference Proceedings (OSTI)

With the popularization and improvement of social and industrial IT development, information appears to explosively increase, and people put much higher expectations on the services of computing, communication and network. Today's public communication ... Keywords: Architectural Strategies, Cloud Computing, Cloud Environments, Communication Network, Computing, Convergence

P. Sasikala

2011-10-01T23:59:59.000Z

391

Enabling cloud interoperability with COMPSs  

Science Conference Proceedings (OSTI)

The advent of Cloud computing has given to researchers the ability to access resources that satisfy their growing needs, which could not be satisfied by traditional computing resources such as PCs and locally managed clusters. On the other side, such ... Keywords: PaaS, cloud computing, data mining, parallel programming models

Fabrizio Marozzo; Francesc Lordan; Roger Rafanell; Daniele Lezzi; Domenico Talia; Rosa M. Badia

2012-08-01T23:59:59.000Z

392

ARM - Measurement - Cloud base height  

NLE Websites -- All DOE Office Websites (Extended Search)

base height base height ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud base height For a given cloud or cloud layer, the lowest level of the atmosphere where cloud properties are detectable. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments BLC : Belfort Laser Ceilometer MPL : Micropulse Lidar MWRP : Microwave Radiometer Profiler RL : Raman Lidar VCEIL : Vaisala Ceilometer External Instruments NOAASURF : NOAA Surface Meteorology Data, collected by NWS and NCDC

393

ARM - Measurement - Cloud ice particle  

NLE Websites -- All DOE Office Websites (Extended Search)

ice particle ice particle ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud ice particle Particles made of ice found in clouds. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments MET : Surface Meteorological Instrumentation Field Campaign Instruments REPLICATOR : Balloon-borne Ice Crystal Replicator CPI : Cloud Particle Imager CVI-AIR : Counterflow Virtual Impactor LEARJET : Lear Jet PARTIMG : Particle imager UAV-PROTEUS-MICRO : Proteus Cloud Microphysics Instruments

394

TWP Island Cloud Trail Studies  

NLE Websites -- All DOE Office Websites (Extended Search)

Pacific Island Cloud Trail Studies Pacific Island Cloud Trail Studies W. M. Porch Los Alamos National Laboratory Los Alamos, New Mexico S. Winiecki University of Chicago Chicago, Illinois Introduction Images and surface temperature measurements from the U.S. Department of Energy (DOE) Multi- spectral Thermal Imaging (MTI) satellite are combined with geostationary meteorological satellite (GMS) images during 2000 and 2001 to better understand cloud trail formation characteristics from the Atmospheric Radiation Measurement (ARM) Tropical Western Pacific (TWP) site. Figure 1 shows a comparison on two consecutive days in December 2000. The day for which a cloud trail developed was more moist and cooler at the altitude the cloud developed (about 600 m) and there was very little

395

ARM - Measurement - Cloud condensation nuclei  

NLE Websites -- All DOE Office Websites (Extended Search)

condensation nuclei condensation nuclei ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud condensation nuclei Small particles (typically 0.0002 mm, or 1/100 th the size of a cloud droplet) about which cloud droplets coalesce. Categories Aerosols, Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CCN : Cloud Condensation Nuclei Particle Counter Field Campaign Instruments AOS : Aerosol Observing System

396

Cloud Computing: Exploring the scope  

E-Print Network (OSTI)

Cloud computing refers a paradigm shift to overall IT solutions while raising the accessibility, scalability and effectiveness through its enabling technologies. However, migrated cloud platforms and services cost benefits as well as performances are neither clear nor summarized. Globalization and the recessionary economic times have not only raised the bar of a better IT delivery models but also have given access to technology enabled services via internet. Cloud computing has vast potential in terms of lean Retail methodologies that can minimize the operational cost by using the third party based IT capabilities, as a service. It will not only increase the ROI but will also help in lowering the total cost of ownership. In this paper we have tried to compare the cloud computing cost benefits with the actual premise cost which an organization incurs normally. However, in spite of the cost benefits, many IT professional believe that the latest model i.e. "cloud computing" has risks and security concerns. This ...

Pandey, Abhinav; Tandon, Ankit; Maurya, Brajesh Kr; Kushwaha, Upendra

2010-01-01T23:59:59.000Z

397

Zenith Radiance Retrieval of Cloud Properties  

NLE Websites -- All DOE Office Websites (Extended Search)

retrievals of cloud properties retrievals of cloud properties from the AMF/COPS campaign Preliminary retrievals of cloud properties from the AMF/COPS campaign Christine Chiu, UMBC/JCET Alexander Marshak, GSFC Yuri Knyazikhin, Boston University Warren Wiscombe, GSFC Christine Chiu, UMBC/JCET Alexander Marshak, GSFC Yuri Knyazikhin, Boston University Warren Wiscombe, GSFC The cloud optical properties of interest are: The cloud optical properties of interest are: * Cloud optical depth Ļ„ - the great unknown * Radiative cloud fraction * Cloud effective drop size, r eff * Cloud optical depth Ļ„ - the great unknown * Radiative cloud fraction * Cloud effective drop size, r eff Ļ„ = 3 2 LWP r eff r eff in Ī¼m, LWP in g/m 2 The 2-ch narrow-field-of-view radiometer (2NFOV) The 2-ch narrow-field-of-view radiometer

398

Potential Oil Production from the Coastal Plain of the Arctic...  

U.S. Energy Information Administration (EIA) Indexed Site

Potential Oil Production from the Coastal Plain of the Arctic National Wildlife Refuge: Updated Assessment 3. Summary The 1.5 million-acre coastal plain of the 19 million-acre...

399

Arctic Precipitation and Evaporation: Model Results and Observational Estimates  

Science Conference Proceedings (OSTI)

Observational estimates of precipitation and evaporation over the Arctic Ocean and its terrestrial watersheds are compared with corresponding values from the climate model simulations of the Atmospheric Model Intercomparison Project (AMIP). ...

John E. Walsh; Vladimir Kattsov; Diane Portis; Valentin Meleshko

1998-01-01T23:59:59.000Z

400

Arctic Tropospheric Winds Derived from TOVS Satellite Retrievals  

Science Conference Proceedings (OSTI)

Accurate three-dimensional wind fields are essential for diagnosing a variety of important climate processes in the Arctic, such as the advection and deposition of heat and moisture, changes in circulation features, and transport of trace ...

Jennifer A. Francis; Elias Hunter; Cheng-Zhi Zou

2005-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

AMOC: Acoustic monitoring of the ocean climate of the Arctic  

Science Conference Proceedings (OSTI)

The overall objective of AMOC is to develop and design an acoustic system for long?term monitoring of the ocean temperature and ice thickness in the Arctic Ocean including the Fram Strait

Ola M. Johannessen; AMOC Group

1999-01-01T23:59:59.000Z

402

Twenty-First-Century Arctic Climate Change in CCSM4  

Science Conference Proceedings (OSTI)

The authors summarize the twenty-first-century Arctic climate simulated by NCAR’s Community Climate System Model, version 4 (CCSM4). Under a strong radiative forcing scenario, the model simulates a much warmer, wetter, cloudier, and stormier ...

Stephen J. Vavrus; Marika M. Holland; Alexandra Jahn; David A. Bailey; Benjamin A. Blazey

2012-04-01T23:59:59.000Z

403

Statistical Characterization of Arctic Polar-Night Jet Oscillation Events  

Science Conference Proceedings (OSTI)

A novel diagnostic tool is presented, based on polar-cap temperature anomalies, for visualizing daily variability of the Arctic stratospheric polar vortex over multiple decades. This visualization illustrates the ubiquity of extended-time-scale ...

Peter Hitchcock; Theodore G. Shepherd; Gloria L. Manney

2013-03-01T23:59:59.000Z

404

Regional Variations of Moist Static Energy Flux into the Arctic  

Science Conference Proceedings (OSTI)

The authors investigate the climmological heating of the Arctic by the atmospheric moist static energy (MSE) flux from lower latitudes based on 25 years (November 1964–1989) of the GFDL dataset. During the five month winter period (NDJFM) the ...

James E. Overland; Philip Turet; Abraham H. Oort

1996-01-01T23:59:59.000Z

405

Stratospheric Forcing of Surface Climate in the Arctic Oscillation  

Science Conference Proceedings (OSTI)

Diagnostic results are presented indicating that during the Arctic oscillation surface climate variations are directly forced by changes in the strength of the stratospheric polar vortex. To be specific, large-scale potential vorticity anomalies ...

Robert X. Black

2002-02-01T23:59:59.000Z

406

Intensification of Geostrophic Currents in the Canada Basin, Arctic Ocean  

Science Conference Proceedings (OSTI)

Continuous sampling of upper-ocean hydrographic data in the Canada Basin from various sources spanning from 2003 through 2011 provides an unprecedented opportunity to observe changes occurring in a major feature of the Arctic Ocean. In a 112-km-...

Miles G. McPhee

2013-05-01T23:59:59.000Z

407

Design options for an Arctic-class LNG carrier  

SciTech Connect

Melville Shipping Ltd., with Petro-Canada's Arctic pilot project, is designing the first commercial LNG system for year-round operations in the Canadian Arctic. Economical adaptation to the region will be maximized by the design combination of current icebreaking and LNG-transport technologies, with special concentration on the ship's hull form, hull structure and materials, LNG-containment system, and propulsion and transmission systems.

Dick, R.A.; Laskov, V.; Wainwright, J.

1979-01-01T23:59:59.000Z

408

Research Highlight  

NLE Websites -- All DOE Office Websites (Extended Search)

Ice Heating Up Cold Clouds Ice Heating Up Cold Clouds Download a printable PDF Submitter: Ovchinnikov, M., Pacific Northwest National Laboratory Area of Research: Cloud Distributions/Characterizations Working Group(s): Cloud-Aerosol-Precipitation Interactions Journal Reference: Ovchinnikov M, A Korolev, and J Fan. 2011. "Effects of ice number concentration on dynamics of a shallow mixed-phase stratiform cloud." Journal of Geophysical Research - Atmospheres, 116, D00T06, doi:10.1029/2011JD015888. The mighty cloud ice crystal appears deceptively delicate but has the power to tip the balance between ice and water in Arctic clouds. This image of an ice crystal was obtained from a Cloud Particle Imager during ISDAC. The imager was mounted on aircraft flying through clouds at a speed of 100 m/s.

409

Discussion of Intelligent Cloud Computing System  

Science Conference Proceedings (OSTI)

Cloud Computing System (CCS) aims to power the next generation data centers and enables application service providers to lease data center capabilities for deploying applications depending on user Quality of Service (QoS) requirements. Huge investments ... Keywords: cloud computing system, intelligent cloud computing system, data warehouse, cloud computing management information system

Yu Hua Zhang; Jian Zhang; Wei Hua Zhang

2010-10-01T23:59:59.000Z

410

Cloud Droplet Size Distributions in Low-Level Stratiform Clouds  

Science Conference Proceedings (OSTI)

A database of stratus cloud droplet (diameter <50 ?m) size distribution parameters, derived from in situ data reported in the existing literature, was created, facilitating intercomparison among datasets and quantifying typical values and their ...

Natasha L. Miles; Johannes Verlinde; Eugene E. Clothiaux

2000-01-01T23:59:59.000Z

411

AIRS Subpixel Cloud Characterization Using MODIS Cloud Products  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) measurements from the Earth Observing System's (EOS's) Aqua satellite enable improved global monitoring of the distribution of clouds. MODIS is ...

Jun Li; W. Paul Menzel; Fengying Sun; Timothy J. Schmit; James Gurka

2004-08-01T23:59:59.000Z

412

Icebergs in the clouds: the other risks of cloud computing  

Science Conference Proceedings (OSTI)

Cloud computing is appealing from management and efficiency perspectives, but brings risks both known and unknown. Well-known and hotly-debated information security risks, due to software vulnerabilities, insider attacks, and side-channels for example, ...

Bryan Ford

2012-06-01T23:59:59.000Z

413

The Role of Cloud Top Entrainment in Cumulus Clouds  

Science Conference Proceedings (OSTI)

The entrainment process and its resultant effects on the microphysics and dynamics within cumuli are not yet clearly understood. This research was undertaken to discover the role which cloud top plays in the entrainment process and to determine ...

Joey F. Boatman; August H. Auer Jr.

1983-06-01T23:59:59.000Z

414

Millimeter Wave Cloud Radar (MMCR) Handbook  

SciTech Connect

The millimeter cloud radar (MMCR) systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities.

KB Widener; K Johnson

2005-01-30T23:59:59.000Z

415

Ocean Heat Transport as a Cause for Model Uncertainty in Projected Arctic Warming  

Science Conference Proceedings (OSTI)

The Arctic climate is governed by complex interactions and feedback mechanisms between the atmosphere, ocean, and solar radiation. One of its characteristic features, the Arctic sea ice, is very vulnerable to anthropogenically caused warming. ...

Irina Mahlstein; Reto Knutti

2011-03-01T23:59:59.000Z

416

An Investigation of an Arctic Front with a Vertically Nested Mesoscale Model  

Science Conference Proceedings (OSTI)

A vertically mesoscale regional numerical weather prediction model is used to simulate an arctic front. The front was observed during the Arctic Cyclone Expedition of 1984. The regional model employs a unique vertical nesting scheme in which the ...

William T. Thompson; Stephen D. Burk

1991-02-01T23:59:59.000Z

417

Mechanisms of Decadal Arctic Climate Variability in the Community Climate System Model, Version 2 (CCSM2)  

Science Conference Proceedings (OSTI)

Several mechanisms have been proposed to explain natural climate variability in the Arctic. These include processes related to the influence of the North Atlantic Oscillation/Arctic Oscillation (NAO/AO), anticyclonic/cyclonic regimes, changes in ...

Hugues Goosse; Marika M. Holland

2005-09-01T23:59:59.000Z

418

The Norwegian IPY–THORPEX: Polar Lows and Arctic Fronts during the 2008 Andųya Campaign  

Science Conference Proceedings (OSTI)

From a weather forecasting perspective, the Arctic poses particular challenges for mainly two reasons: 1) The observational data are sparse and 2) the weather phenomena responsible for severe weather, such as polar lows, Arctic fronts, and orographic ...

J. E. Kristjįnsson; I. Barstad; T. Aspelien; I. Fųre; Ų. Godųy; Ų. Hov; E. Irvine; T. Iversen; E. Kolstad; T. E. Nordeng; H. McInnes; R. Randriamampianina; J. Reuder; Ų. Saetra; M. Shapiro; T. Spengler; H. Ólafsson

2011-11-01T23:59:59.000Z

419

The Effects of Different Climate Input Datasets on Simulated Carbon Dynamics in the Western Arctic  

Science Conference Proceedings (OSTI)

As part of the Western Arctic Linkage Experiment (WALE), simulations of carbon dynamics in the western Arctic (WALE region) were conducted during two recent decades by driving the Terrestrial Ecosystem Model (TEM) with three alternative climate ...

Joy Clein; A. David McGuire; Eugenie S. Euskirchen; Monika Calef

2007-08-01T23:59:59.000Z

420

Do General Circulation Models Underestimate the Natural Variability in the Arctic Climate?  

Science Conference Proceedings (OSTI)

The authors examine the natural variability of the arctic climate system simulated by two very different models: the Geophysical Fluid Dynamics Laboratory (GFDL) global climate model, and an area-averaged model of the arctic atmosphere–sea ice–...

D. S. Battisti; C. M. Bitz; R. E. Moritz

1997-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

DOE/SC-ARM-10-034 The Arctic Lower Troposphere Observed  

NLE Websites -- All DOE Office Websites (Extended Search)

since the late 1960s. Inter-model scatter in projected Arctic temperatures is also an order of magnitude larger in the Arctic than in mid- latitudes. Current climate models do...

422

ARM - Field Campaign - Cloud IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsCloud IOP govCampaignsCloud IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Cloud IOP 1998.04.27 - 1998.05.17 Lead Scientist : Gerald Mace For data sets, see below. Summary Monday, April 27, 1998 IOP Opening Activities: Heavy rain (nearly 2.5" since 12Z 4/26/98) at the central facility (CF) dominated the first day of the Cloud Physics/Single Column Model IOP and limited the daily activities. A 1430 GMT sonde launch commenced the 3-hour sonde launch schedule at the CF and 4 boundary facilities (BFs). Scientists/Instrumentation on Site: Citation: Has arrived and is located at the Ponca City Airport. No flights are currently planned. Flights are tentatively planned for stratus sampling when precipitation ends.

423

Clouds, Aerosols and Precipitation in  

NLE Websites -- All DOE Office Websites (Extended Search)

the Marine Boundary Layer (CAP-MBL) Graciosa Island, Azores, NE Atlantic Ocean Graciosa Island, Azores, NE Atlantic Ocean May 2009-December 2010 May 2009-December 2010 Rob Wood, University of Washington Rob Wood, University of Washington AMF Deployment Team Thanks to Mark Miller: AMF Site Scientist Mark Miller: AMF Site Scientist Kim Nitschke: AMF Site Manager CAP-MBL Proposal Team Importance of Low-Clouds for Climate Imperative that we understand the processes controlling the formation, maintenance and dissipation of low clouds in order to formation, maintenance and dissipation of low clouds in order to improve their representation in climate models. Which clouds matter for climate sensitivity? Cli t F db k

424

NIST Cloud Computing Standards Roadmap  

Science Conference Proceedings (OSTI)

... in this clause is a natural extension to the ... which take advantage of the homogeneity and power of cloud ... such as WS-I) and grid standards (such as ...

2013-08-07T23:59:59.000Z

425

Fractal Statistics of Cloud Fields  

Science Conference Proceedings (OSTI)

Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) data, with 80 and 30 m spatial resolution, respectively, have been employed to study the spatial structure of boundary-layer and intertropical convergence zone (ITCZ) clouds. The ...

Robert F. Cahalan; Joachim H. Joseph

1989-02-01T23:59:59.000Z

426

Cloud Cover and Climate Sensitivity  

Science Conference Proceedings (OSTI)

This study discusses how the sensitivity of climate may be affected by the variation of cloud cover based on the results from numerical experiments with a highly simplified, three-dimensional model of the atmospheric general circulation. The ...

Richard T. Wetherald; Syukuro Manabe

1980-07-01T23:59:59.000Z

427

Cloud computing for dynamic systems  

Science Conference Proceedings (OSTI)

Cloud computing is a fast emerging model for enabling dynamic on-demand computing and IT-based services. It promotes dynamic properties and characteristics such as scalability, agility, flexibility, virtualised and distributed on-demand computing. However, ...

Khaled Sabry

2011-11-01T23:59:59.000Z

428

Breaking the Cloud Parameterization Deadlock  

Science Conference Proceedings (OSTI)

A key factor limiting the reliability of simulations of anthropogenic climate change is the inability to accurately represent the various effects of clouds on climate. Despite the best efforts of the community, the problem has resisted solution ...

David Randall; Marat Khairoutdinov; Akio Arakawa; Wojciech Grabowski

2003-11-01T23:59:59.000Z

429

The Hercules-Aquila Cloud  

E-Print Network (OSTI)

We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of about 40 degrees and extends above and below the Galactic plane by at least 50 degrees. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila Cloud is related to the bulge or thick disk. More likely, this is a new structural component of the Galaxy that passes through the disk. The Cloud stretches about 80 degrees in longitude. Its heliocentric distance lies between 10 and 20 kpc so that the extent of the Cloud in projection is roughly 20 kpc by 15 kpc. It has an absolute magnitude of -13 and its stellar population appears to be comparable to, but somewhat more metal-rich than, M92.

Belokurov, V; Bell, E F; Irwin, M J; Hewett, P C; Koposov, S; Rockosi, C M; Gilmore, G; Zucker, D B; Fellhauer, M; Wilkinson, M I; Bramich, D M; Vidrih, S; Rix, H W; Beers, T C; Schneider, D P; Barentine, J C; Brewington, H; Brinkmann, J; Harvanek, M; Krzesķnski, J; Long, D; Pan, K; Snedden, S A; Malanushenko, O; Malanushenko, V

2007-01-01T23:59:59.000Z

430

The Hercules-Aquila Cloud  

E-Print Network (OSTI)

We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of about 40 degrees and extends above and below the Galactic plane by at least 50 degrees. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila Cloud is related to the bulge or thick disk. More likely, this is a new structural component of the Galaxy that passes through the disk. The Cloud stretches about 80 degrees in longitude. Its heliocentric distance lies between 10 and 20 kpc so that the extent of the Cloud in projection is roughly 20 kpc by 15 kpc. It has an absolute magnitude of -13 and its stellar population appears to be comparable to, but somewhat more metal-rich than, M92.

V. Belokurov; N. W. Evans; E. F. Bell; M. J. Irwin; P. C. Hewett; S. Koposov; C. M. Rockosi; G. Gilmore; D. B. Zucker; M. Fellhauer; M. I. Wilkinson; D. M. Bramich; S. Vidrih; H. -W. Rix; T. C. Beers; D. P. Schneider; J. C. Barentine; H. Brewington; J. Brinkmann; M. Harvanek; J. Krzesinski; D. Long; K. Pan; S. A. Snedden; O. Malanushenko; V. Malanushenko

2007-01-27T23:59:59.000Z

431

Microsoft Word - fridland_a.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

Field Measurements and Numerical Simulations to Field Measurements and Numerical Simulations to Constrain Mechanisms of Ice Formation During the Mixed-Phase Arctic Cloud Experiment Intensive Operational Period A. Fridlind and A. Ackerman National Aeronautics and Space Administration - Goddard Institute for Space Studies New York, New York Introduction Mechanisms of ice formation in supercooled clouds that are too warm to allow the homogeneous nucleation of water remain poorly constrained by measurements (e.g., Cotton and Field 2002). Ice mass and number concentrations have long been thought to exceed what can be quantitatively explained by simultaneous measurements of ice nuclei (e.g., Koenig 1963; Beard 1992). In late 2004 at the Atmospheric Radiation Measurement program's North Slope of Alaska site, the Mixed-Phase Arctic

432

Comparison of an Experimental NOAA AVHRR Cloud Dataset with Other Observed and Forecast Cloud Datasets  

Science Conference Proceedings (OSTI)

CLAVR [cloud from AVHRR (Advanced Very High Resolution Radiometer)] is a global cloud dataset under development at NOAA/NESDIS (National Environmental Satellite, Data, and Information Service). Total cloud amount from two experimental cases, 9 ...

Yu-Tai Hou; Kenneth A. Campana; Kenneth E. Mitchell; Shi-Keng Yang; Larry L. Stowe

1993-12-01T23:59:59.000Z

433

ISCCP Cloud Properties Associated with Standard Cloud Types Identified in Individual Surface Observations  

Science Conference Proceedings (OSTI)

Individual surface weather observations from land stations and ships are compared with individual cloud retrievals of the International Satellite Cloud Climatology Project (ISCCP), stage C1, for an 8-yr period (1983–91) to relate cloud optical ...

Carole J. Hahn; William B. Rossow; Stephen G. Warren

2001-01-01T23:59:59.000Z

434

Biogeography of Tropical Montane Cloud Forests. Part II: Mapping of Orographic Cloud Immersion  

Science Conference Proceedings (OSTI)

This study details two unique methods to quantify cloud-immersion statistics for tropical montane cloud forests (TMCFs). The first technique uses a new algorithm for determining cloud-base height using Moderate Resolution Imaging ...

Udaysankar S. Nair; Salvi Asefi; Ronald M. Welch; D. K. Ray; Robert O. Lawton; Vani Starry Manoharan; Mark Mulligan; Tom L. Sever; Daniel Irwin; J. Alan Pounds

2008-08-01T23:59:59.000Z

435

Cloud-Resolving Simulation of Low-Cloud Feedback to an Increase in Sea Surface Temperature  

Science Conference Proceedings (OSTI)

This study investigates the physical mechanisms of the low cloud feedback through cloud-resolving simulations of cloud-radiative equilibrium response to an increase in sea surface temperature (SST). Six pairs of perturbed and control simulations ...

Kuan-Man Xu; Anning Cheng; Minghua Zhang

2010-03-01T23:59:59.000Z

436

Aircraft Microphysical Documentation from Cloud Base to Anvils of Hailstorm Feeder Clouds in Argentina  

Science Conference Proceedings (OSTI)

Documentation during January and February 2000 of the structure of severe convective storms in Mendoza, Argentina, with a cloud-physics jet aircraft penetrating the major feeder clouds from cloud base to the ?45°C isotherm level is reported. ...

Daniel Rosenfeld; William L. Woodley; Terrence W. Krauss; Viktor Makitov

2006-09-01T23:59:59.000Z

437

Biogeography of Tropical Montane Cloud Forests. Part I: Remote Sensing of Cloud-Base Heights  

Science Conference Proceedings (OSTI)

Cloud-base heights over tropical montane cloud forests are determined using Moderate Resolution Imaging Spectroradiometer (MODIS) cloud products and National Centers for Environmental Prediction global tropospheric final analysis (FNL) fields. ...

Ronald M. Welch; Salvi Asefi; Jian Zeng; Udaysankar S. Nair; Qingyuan Han; Robert O. Lawton; Deepak K. Ray; Vani Starry Manoharan

2008-04-01T23:59:59.000Z

438

The Experimental Cloud Lidar Pilot Study (ECLIPS) for Cloud—Radiation Research  

Science Conference Proceedings (OSTI)

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 ...

C. M. Platt; S. A. Young; A. I. Carswell; S. R. Pal; M. P. McCormick; D. M. Winker; M. DelGuasta; L. Stefanutti; W. L. Eberhard; M. Hardesty; P. H. Flamant; R. Valentin; B. Forgan; G. G. Gimmestad; H. Jäger; S. S. Khmelevtsov; I. Kolev; B. Kaprieolev; Da-ren Lu; K. Sassen; V. S. Shamanaev; O. Uchino; Y. Mizuno; U. Wandinger; C. Weitkamp; A. Ansmann; C. Wooldridge

1994-09-01T23:59:59.000Z

439

Estimation of Cloud Physical Parameters from Airborne Solar Spectral Reflectance Measurements for Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

A new method is proposed to retrieve various cloud physical parameters of water clouds from the solar-flux reflectances at four wavelengths measured by using the airborne Multi-channel Cloud Pyranometer (MCP) system. The MCP system was designed ...

Shoji Asano; Masataka Shiobara; Akihiro Uchiyama

1995-10-01T23:59:59.000Z

440

Kinetics of Cloud Drop Formation and Its Parameterization for Cloud and Climate Models  

Science Conference Proceedings (OSTI)

To study the kinetics of drop nucleation in clouds, the integro–differential equation for integral water supersaturation in cloud is derived and analyzed. Solving the supersaturation equation with an algebraic form of the cloud condensation ...

Vitaly I. Khvorostyanov; Judith A. Curry

2008-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Eggs Show Arctic Mercury Cycling May Be Linked to Ice Cover  

Science Conference Proceedings (OSTI)

... cycling of mercury in the Arctic biosphere. Credit: D. Roseneau, US Fish and Wildlife Service View hi-resolution image. ...

2011-01-20T23:59:59.000Z

442

An Improved Cloud Classification Algorithm Based on the SGP CART...  

NLE Websites -- All DOE Office Websites (Extended Search)

studies which need to group clouds according to cloud types, but also provides necessary information to implement different retrieval algorithms to generate integrated cloud...

443

Cloud-state-dependent Sampling in AIRS Observations based on CloudSat Cloud Classification  

Science Conference Proceedings (OSTI)

The precision, accuracy, and potential sampling biases of temperature (T) and water vapor (q) vertical profiles obtained by satellite infrared sounding instruments are highly cloud-state dependent and poorly quantified. We describe progress ...

Qing Yue; Eric J. Fetzer; Brian H. Kahn; Sun Wong; Gerald Manipon; Alexandre Guillaume; Brian Wilson

444

Modeling the subsurface thermal impact of Arctic thaw lakes in a warming climate  

Science Conference Proceedings (OSTI)

Warming air temperatures in the Arctic are modifying the rates of thermokarst processes along Alaska's Arctic Coastal Plain. The Arctic Coastal Plain is dominated by thaw lakes. These kilometer-scale lakes are the most visible surface features in the ... Keywords: MATLAB, Numerical model, Permafrost, Thaw lakes, Thermal model

N. Matell; R. S. Anderson; I. Overeem; C. Wobus; F. E. Urban; G. D. Clow

2013-04-01T23:59:59.000Z

445

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

E-Print Network (OSTI)

In this study, it is hypothesized that the mesoscale environment can indirectly control the cloud-to-ground (CG) lightning 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 observational and laboratory charging studies, suggests that broad, strong updrafts and associated large liquid water contents in severe storms lead to enhanced positive charging of graupel and hail via the noninductive charging mechanism, the generation of an inverted charge structure, and increased positive CG lightning production. The corollary is that environmental conditions favoring these kinematic and microphysical characteristics should support severe storms generating an anomalously high (> 25%) percentage of positive CG lightning (i.e., positive storms), while environmental conditions relatively less favorable should sustain storms characterized by a typical (? 25%) percentage of positive CG lightning (i.e., negative storms). Forty-eight inflow proximity soundings were analyzed to characterize the environments of nine distinct mesoscale regions of severe storms (four positive and five negative) on six days during May – June 2002 over the central United States. This analysis clearly demonstrated significant and systematic differences in the mesoscale environments of positive and negative storms, which were consistent with the stated hypothesis. When compared to negative storms, positive storms occurred in environments associated with a drier low to midtroposphere, higher cloud base height, smaller warm cloud depth, stronger conditional instability, larger 0-3 km AGL wind shear, stronger 0-2 km AGL storm-relative wind speed, and larger buoyancy in the mixed-phase zone, at a statistically significant level. Differences in the warm cloud depth of positive and negative storms were by far the most dramatic, suggesting an important role for this parameter in controlling CG lightning polarity. Subjective visual inspection of radar imagery revealed no strong relationship between convective mode and CG lightning polarity, and also illustrated that positive and negative severe storms can be equally intense.

Buffalo, Kurt Matthew

2007-12-01T23:59:59.000Z

446

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

E-Print Network (OSTI)

In this study, it is hypothesized that the mesoscale environment can indirectly control the cloud-to-ground (CG) lightning 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 observational and laboratory charging studies, suggests that broad, strong updrafts and associated large liquid water contents in severe storms lead to enhanced positive charging of graupel and hail via the noninductive charging mechanism, the generation of an inverted charge structure, and increased positive CG lightning production. The corollary is that environmental conditions favoring these kinematic and microphysical characteristics should support severe storms generating an anomalously high (> 25%) percentage of positive CG lightning (i.e., positive storms), while environmental conditions relatively less favorable should sustain storms characterized by a typical (? 25%) percentage of positive CG lightning (i.e., negative storms). Forty-eight inflow proximity soundings were analyzed to characterize the environments of nine distinct mesoscale regions of severe storms (four positive and five negative) on six days during May - June 2002 over the central United States. This analysis clearly demonstrated significant and systematic differences in the mesoscale environments of positive and negative storms, which were consistent with the stated hypothesis. When compared to negative storms, positive storms occurred in environments associated with a drier low to midtroposphere, higher cloud base height, smaller warm cloud depth, stronger conditional instability, larger 0-3 km AGL wind shear, stronger 0-2 km AGL storm-relative wind speed, and larger buoyancy in the mixed-phase zone, at a statistically significant level. Differences in the warm cloud depth of positive and negative storms were by far the most dramatic, suggesting an important role for this parameter in controlling CG lightning polarity. Subjective visual inspection of radar imagery revealed no strong relationship between convective mode and CG lightning polarity, and also illustrated that positive and negative severe storms can be equally intense.

Buffalo, Kurt Matthew

2007-12-01T23:59:59.000Z

447

Preliminary Geospatial Analysis of Arctic Ocean Hydrocarbon Resources  

SciTech Connect

Ice coverage of the Arctic Ocean is predicted to become thinner and to cover less area with time. The combination of more ice-free waters for exploration and navigation, along with increasing demand for hydrocarbons and improvements in technologies for the discovery and exploitation of new hydrocarbon resources have focused attention on the hydrocarbon potential of the Arctic Basin and its margins. The purpose of this document is to 1) summarize results of a review of published hydrocarbon resources in the Arctic, including both conventional oil and gas and methane hydrates and 2) develop a set of digital maps of the hydrocarbon potential of the Arctic Ocean. These maps can be combined with predictions of ice-free areas to enable estimates of the likely regions and sequence of hydrocarbon production development in the Arctic. In this report, conventional oil and gas resources are explicitly linked with potential gas hydrate resources. This has not been attempted previously and is particularly powerful as the likelihood of gas production from marine gas hydrates increases. Available or planned infrastructure, such as pipelines, combined with the geospatial distribution of hydrocarbons is a very strong determinant of the temporal-spatial development of Arctic hydrocarbon resources. Significant unknowns decrease the certainty of predictions for development of hydrocarbon resources. These include: 1) Areas in the Russian Arctic that are poorly mapped, 2) Disputed ownership: primarily the Lomonosov Ridge, 3) Lack of detailed information on gas hydrate distribution, and 4) Technical risk associated with the ability to extract methane gas from gas hydrates. Logistics may control areas of exploration more than hydrocarbon potential. Accessibility, established ownership, and leasing of exploration blocks may trump quality of source rock, reservoir, and size of target. With this in mind, the main areas that are likely to be explored first are the Bering Strait and Chukchi Sea, in spite of the fact that these areas do not have highest potential for future hydrocarbon reserves. Opportunities for improving the mapping and assessment of Arctic hydrocarbon resources include: 1) Refining hydrocarbon potential on a basin-by-basin basis, 2) Developing more realistic and detailed distribution of gas hydrate, and 3) Assessing the likely future scenarios for development of infrastructure and their interaction with hydrocarbon potential. It would also be useful to develop a more sophisticated approach to merging conventional and gas hydrate resource potential that considers the technical uncertainty associated with exploitation of gas hydrate resources. Taken together, additional work in these areas could significantly improve our understanding of the exploitation of Arctic hydrocarbons as ice-free areas increase in the future.

Long, Philip E.; Wurstner, Signe K.; Sullivan, E. C.; Schaef, Herbert T.; Bradley, Donald J.

2008-10-01T23:59:59.000Z

448

Evaluation of Arctic Broadband Surface Radiation Measurements  

Science Conference Proceedings (OSTI)

The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that rotate sensors and shading devices that track the sun. High quality measurements require striking a balance between locating sensors in a pristine undisturbed location free of artificial blockage (such as buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data include solar tracker malfunctions, rime/frost/snow deposition on the instruments and operational problems due to limited operator access in extreme weather conditions. In this study, a comparison is made between the global and component sum (direct [vertical component] + diffuse) shortwave measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both shortwave and longwave measurements. Solutions to these operational problems are proposed that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols.

Matsui, N.; Long, Charles N.; Augustine, J. A.; Halliwell, D.; Uttal, Taneil; Longenecker, D.; Niebergale, J.; Wendell, J.; Albee, R.

2012-02-24T23:59:59.000Z

449

ARM - Field Campaign - Arctic Winter Water Vapor IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsArctic Winter Water Vapor IOP govCampaignsArctic Winter Water Vapor IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Arctic Winter Water Vapor IOP 2004.03.09 - 2004.04.09 Lead Scientist : Ed Westwater Data Availability http://www.etl.noaa.gov/programs/2004/wviop/data will contain quicklooks of all of the data. For data sets, see below. Summary During the IOP, the Ground-based Scanning Radiometer of NOAA/ETL, and the ARM MicroWave Radiometer and Microwave Profiler, yielded excellent data over a range of conditions. In all, angular-scanned and calibrated radiometric data from 22.345 to 380 GHz were taken. The Precipitable Water Vapor varied about an order of magnitude from 1 to 10 mm, and surface temperatures varied from about -10 to -40 deg. Celcius. Vaisala RS90

450

Carbon Dioxide and Climate: Mechanisms of Changes in Cloud  

Science Conference Proceedings (OSTI)

Changes in cloud distribution may provide a major feedback on climate change. General circulation model simulations show an upward shift of high cloud and a general reduction of free-tropospheric cloud when climate warms. The shift of high cloud ...

J. F. B. Mitchell; W. J. Ingram

1992-01-01T23:59:59.000Z

451

A Critical Review of the Australian Experience in Cloud Seeding  

Science Conference Proceedings (OSTI)

From 1947 to 1994 a number of cloud-seeding experiments were done in Australia based on the static cloud-seeding hypothesis. A critical analysis of these successive cloud-seeding experiments, coupled with microphysical observations of the clouds, ...

Brian F. Ryan; Warren D. King

1997-02-01T23:59:59.000Z

452

Evaluation of AIRS cloud thermodynamic phase determination with CALIPSO  

Science Conference Proceedings (OSTI)

The Atmospheric Infrared Sounder (AIRS) infrared-based cloud thermodynamic phase retrievals are evaluated using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) cloud thermodynamic phase. The AIRS cloud phase is ...

Hongchun Jin; Shaima L. Nasiri

453

Influence of Cloud Condensation Nuclei on Orographic Snowfall  

Science Conference Proceedings (OSTI)

Pollution aerosols acting as cloud condensation nuclei (CCN) have the potential to alter warm rain clouds via the aerosol first and second indirect effects in which they modify the cloud droplet population, cloud lifetime and size, rainfall ...

Stephen M. Saleeby; William R. Cotton; Douglas Lowenthal; Randolph D. Borys; Melanie A. Wetzel

2009-05-01T23:59:59.000Z

454

Arctic Oil and Natural Gas Potential Philip Budzik U.S. Energy Information Administration  

Gasoline and Diesel Fuel Update (EIA)

Arctic Oil and Natural Gas Potential Arctic Oil and Natural Gas Potential Philip Budzik U.S. Energy Information Administration Office of Integrated Analysis and Forecasting Oil and Gas Division October, 2009 Introduction The Arctic is defined as the Northern hemisphere region located north of the Arctic Circle, the circle of latitude where sunlight is uniquely present or absent for 24 continuous hours on the summer and winter solstices, respectively. The Arctic Circle spans the globe at 66.56Ā° (66Ā°34') north latitude (Figure 1). 1 The Arctic could hold about 22 percent of the world's undiscovered conventional oil and natural gas resources. The prospects for Arctic oil and natural gas production are discussed taking into consideration the nature of the resources, the cost of developing them, and the

455

ARM - Measurement - Cloud optical depth  

NLE Websites -- All DOE Office Websites (Extended Search)

optical depth optical depth ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud optical depth Amount of light cloud droplets or ice particles prevent from passing through a column of atmosphere. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. External Instruments GOES : Geostationary Operational Environmental Satellites Field Campaign Instruments EC-CONVAIR580-BULK : Environment Canada Convair 580 Bulk Parameters GOES : Geostationary Operational Environmental Satellites

456

Ice in Clouds Experiment–Layer Clouds. Part II: Testing Characteristics of Heterogeneous Ice Formation in Lee Wave Clouds  

Science Conference Proceedings (OSTI)

Heterogeneous ice nucleation is a source of uncertainty in models that represent ice clouds. The primary goal of the Ice in Clouds Experiment–Layer Clouds (ICE-L) field campaign was to determine if a link can be demonstrated between ice ...

P. R. Field; A. J. Heymsfield; B. J. Shipway; P. J. DeMott; K. A. Pratt; D. C. Rogers; J. Stith; K. A. Prather

2012-03-01T23:59:59.000Z

457

Cloud Detection with MODIS. Part II: Validation  

Science Conference Proceedings (OSTI)

An assessment of the performance of the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask algorithm for Terra and Aqua satellites is presented. The MODIS cloud mask algorithm output is compared with lidar observations from ground [...

S. A. Ackerman; R. E. Holz; R. Frey; E. W. Eloranta; B. C. Maddux; M. McGill

2008-07-01T23:59:59.000Z

458

Cloud Color and Ocean Radiant Heating  

Science Conference Proceedings (OSTI)

It is well recognized that clouds regulate the flux of solar radiation reaching the sea surface. Clouds also affect the spectral distribution of incident irradiance. Observations of spectral and total incident solar irradiance made from the ...

David A. Siegel; Toby K. Westberry; J. Carter Ohlmann

1999-04-01T23:59:59.000Z

459

Near-Global Observations of Low Clouds  

Science Conference Proceedings (OSTI)

This paper analyzes several near-global datasets of low cloud cover, including the the International Satellite Cloud Climatology Project (ISCCP) satellite observations, C. J. Hahn et al. surface-derived observations, and the National Centers for ...

Bryan C. Weare

2000-04-01T23:59:59.000Z

460

Analytical Solutions for Cloud-Drop Concentration  

Science Conference Proceedings (OSTI)

This note compares and evaluates the analytical solutions of Squires and Twomey for cloud droplet concentration. Either solution is likely to be fairly accurate (±30%) when the slope parameter (?) of the cloud condensation nuclei distribution is ...

David B. Johnson

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Comparison of ISCCP and Other Cloud Amounts  

Science Conference Proceedings (OSTI)

A new 8-year global cloud climatology has been produced by the International Satellite Cloud Climatology Project (ISCCP) that provides information every 3 h at 280-km spatial resolution covering the period from July 1983 through June 1991. If ...

William B. Rossow; Alison W. Walker; Leonid C. Garder

1993-12-01T23:59:59.000Z

462

ARM - Field Campaign - Spring Cloud IOP  

NLE Websites -- All DOE Office Websites (Extended Search)

govCampaignsSpring Cloud IOP govCampaignsSpring Cloud IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Spring Cloud IOP 2000.03.01 - 2000.03.26 Lead Scientist : Gerald Mace For data sets, see below. Summary The Atmospheric Radiation Measurement (ARM) Program conducted a Cloud Intensive Operational Period (IOP) in March 2000 that was the first-ever effort to document the 3-dimensional cloud field from observational data. Prior numerical studies of solar radiation propagation through the atmosphere in the presence of clouds have been limited by the necessity to use theoretical representations of clouds. Three-dimensional representations of actual clouds and their microphysical properties, such as the distribution of ice and water, had previously not been possible

463

Ground-based Microwave Cloud Tomography  

NLE Websites -- All DOE Office Websites (Extended Search)

Microwave Cloud Tomography Microwave Cloud Tomography Experiment, SGP, May 15-June 15, 2009 Lead Scientist Dong Huang, BNL Co-Investigators Al Gasiewski, UC Boulder Maria Cadeddu, ANL Warren Wiscombe, BNL Radiation Processes Working Group March 30, 2009 multiple radiometers All good cloud radiation modelers should close their airplane window shades so as not to be corrupted by the spectacle of real 3D clouds. - Roger Davies In case you forget to do this, you see 3/30/2009 ARM RPWG 2 Effects of cloud structure on radiation 3/30/2009 ARM RPWG 3 Typical climate model - Cloud fraction & mean water content - Horizontally uniform clouds, no side radiation - Assumption on overlap Courtesy of Bernhard Mayer Cloud structure important to radiation - Cumulus (Benner & Evans 2001, Pincus et al. 2005), deep convection (DiGiuseppe &

464

Entrainment and Detrainment in Cumulus Clouds  

Science Conference Proceedings (OSTI)

Vertical redistribution of air and its properties inside convective clouds can be studied by standard thermodynamic analyses (Paluch and saturation point diagrams) if the clouds are nonprecipitating and ice free. It is shown from such analysis ...

Gregory R. Taylor; Marcia B. Baker

1991-01-01T23:59:59.000Z

465

Tropical Thermostats and Low Cloud Cover  

Science Conference Proceedings (OSTI)

The ability of subtropical stratus low cloud cover to moderate or amplify the tropical response to climate forcing such as increased CO2 is considered. Cloud radiative forcing over the subtropics is parameterized using an empirical relation ...

R. L. Miller

1997-03-01T23:59:59.000Z

466

Cloud Condensation Nuclei and Ship Tracks  

Science Conference Proceedings (OSTI)

Enhancements of droplet concentrations in clouds affected by four ships were fairly accurately predicted from ship emission factors and plume and background cloud condensation nucleus (CCN) spectra. Ship exhausts thus accounted for the increased ...

James G. Hudson; Timothy J. Garrett; Peter V. Hobbs; Scott R. Strader; Yonghong Xie; Seong Soo Yum

2000-08-01T23:59:59.000Z

467

Global Cloud Climatologies: A Historical Review  

Science Conference Proceedings (OSTI)

Accurate global cloud information is required for many climate studies, particularly for validation of climate model simulations. This paper reviews the cloud climatologies currently available, identifying and attempting to explain the ...

N. A. Hughes

1984-05-01T23:59:59.000Z

468

The Tropical Warm Pool International Cloud Experiment  

Science Conference Proceedings (OSTI)

A comprehensive dataset describing tropical cloud systems and their environmental setting and impacts has been collected during the Tropical Warm Pool International Cloud Experiment (TWP-ICE) and Aerosol and Chemical Transport in Tropical ...

Peter T. May; James H. Mather; Geraint Vaughan; Keith N. Bower; Christian Jakob; Greg M. McFarquhar; Gerald G. Mace

2008-05-01T23:59:59.000Z

469

Simultaneous Occurrence of Different Cloud Types  

Science Conference Proceedings (OSTI)

Cloud observations from land stations and from ships in the ocean are used to investigate the frequency of observation and the co-occurrence of different cloud types, and the geographical and seasonal variations of these co-occurrences. Ground-...

Stephen G. Warren; Carole J. Hahn; Julius London

1985-07-01T23:59:59.000Z

470

Radar and Radiation Properties of Ice Clouds  

Science Conference Proceedings (OSTI)

The authors derive relations of the equivalent radar reflectivity Ze and extinction coefficient ? of ice clouds and confirm the theory by in situ aircraft observations during the First International Satellite Cloud Climatology Project Regional ...

David Atlas; Sergey Y. Matrosov; Andrew J. Heymsfield; Ming-Dah Chou; David B. Wolff

1995-11-01T23:59:59.000Z

471

Scale Localization of Cloud Particle Clustering Statistics  

Science Conference Proceedings (OSTI)

Recent work has examined the spatial distribution of droplets within a cloud. Experimentally, most studies analyze interevent times from static probes flown linearly through a cloud, allowing the spatial information to be conveyed through a time ...

Michael L. Larsen

2012-11-01T23:59:59.000Z

472

Cloud Particle Phase Determination with the AVHRR  

Science Conference Proceedings (OSTI)

An accurate determination of cloud particle phase is required for the retrieval of other cloud properties from satellite and for radiative flux calculations in climate models. The physical principles underlying phase determination using the ...

Jeffrey R. Key; Janet M. Intrieri

2000-10-01T23:59:59.000Z

473

Aquaplanets, Climate Sensitivity, and Low Clouds  

Science Conference Proceedings (OSTI)

Cloud effects have repeatedly been pointed out as the leading source of uncertainty in projections of future climate, yet clouds remain poorly understood and simulated in climate models. Aquaplanets provide a simplified framework for comparing ...

Brian Medeiros; Bjorn Stevens; Isaac M. Held; Ming Zhao; David L. Williamson; Jerry G. Olson; Christopher S. Bretherton

2008-10-01T23:59:59.000Z

474

Satellite Remote Sensing of Multiple Cloud Layers  

Science Conference Proceedings (OSTI)

The goals of the current study are threefold: 1) to present a multispectral, multiresolution (MSMR) methodology for analysis of scenes containing multiple cloud layers; 2) to apply the MSMR method to two multilevel cloud scenes recorded by the ...

B.A. Baum; T. Uttal; M. Poellot; T.P. Ackerman; J.M. Alvarez; J. Intrieri; D.O'C. Starr; J. Titlow; V. Tovinkere; E. Clothiaux

1995-12-01T23:59:59.000Z

475

Precipitation and Cloud Structure in Midlatitude Cyclones  

Science Conference Proceedings (OSTI)

Composite mean fields and probability distribution functions (PDFs) of rain rate, cloud type and cover, cloud-top temperature, surface wind velocity, and water vapor path (WVP) are constructed using satellite observations of midlatitude cyclones ...

Paul R. Field; Robert Wood

2007-01-01T23:59:59.000Z

476

Cloud Optical Thickness Estimation from Irradiance Measurements  

Science Conference Proceedings (OSTI)

Radiative transfer algorithms are developed to estimate the optical thickness of clouds using an irradiance detector located above, deep within, and beneath a cloud. Both monodirectional and diffuse illumination cases are considered. For each ...

H. C. Yi; N. J. McCormick; R. Sanchez

1990-11-01T23:59:59.000Z

477

Does Mixing Promote Cloud Droplet Growth?  

Science Conference Proceedings (OSTI)

A systematic examination of cloud droplet size spectra from the Cooperative Convective Precipitation Experiment (CCOPE) reveals no tendency for an increase in the maximum droplet size with increasing dilution or cloud age.

Ilga R. Paluch; Charles A. Knight

1986-09-01T23:59:59.000Z

478

Thin Cloud Length Scales Using CALIPSO and CloudSat Data  

E-Print Network (OSTI)

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 the study of these clouds. Using one of these joint cloud products, 2B-GEOPROF-Lidar, and a post-processing algorithm designed to find horizontally continuous thin clouds within the cloud product, the locations, length scales, and vertical distributions by length of thin clouds are determined. It is found that thin clouds vary in length from a few km to over 2900 km and tend to be longer in the tropical upper troposphere than lower in the atmosphere and at higher latitudes. In the upper troposphere between 0° and 40°N, over 20% of all thin cloud measurements in the 2B-GEOPROF-Lidar product are contributed by thin clouds that are longer than 500 km. In fact, in this latitude range, over 65% of all thin cloud measurements are contributed by clouds longer than 100 km. Also, thin cloud length and frequency differ between the four seasons in the year of data used here.

Solbrig, Jeremy E.

2009-08-01T23:59:59.000Z

479

SPACE4CLOUD: a tool for system performance and costevaluation of cloud systems  

Science Conference Proceedings (OSTI)

Cloud Computing is assuming a relevant role in the world of web applications and web services. Cloud technologies allow to build dynamic systems which are able to adapt their performance to workload fluctuations delegating to the Cloud Provider the intensive ... Keywords: cloud computing, model-driven software development, performance prediction

Davide Franceschelli; Danilo Ardagna; Michele Ciavotta; Elisabetta Di Nitto

2013-04-01T23:59:59.000Z

480

Standards Acceleration to Jumpstart Adoption of Cloud ...  

Science Conference Proceedings (OSTI)

... Standards Acceleration to Jumpstart Adoption of Cloud Computing (SAJACC). The goal of the SAJACC initiative is to drive ...

2013-07-02T23:59:59.000Z

Note: This page contains sample records for the topic "arctic mixed-phase cloud" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Cloud Application Architectures: Building Applications and Infrastructure in the Cloud  

Science Conference Proceedings (OSTI)

Much is said about the advantages and risks of cloud computing, but how do you actually create a web application for this environment or migrate existing applications to it? With this book, you'll learn the programming and system administration skills ...

George Reese

2009-04-01T23:59:59.000Z

482

When Clouds become Green: the Green Open Cloud Architecture  

E-Print Network (OSTI)

. They differ from Grids as explained in [2] and can be part of the next-generation data centers with ensl to the requirements of distributed applications. Cloud systems provide on-demand computing power and storage, so of the electric cost of a virtual machine in Section 2. Section 3 outlines the architecture and the components

Paris-Sud XI, UniversitƩ de

483

Vertical Mixing in Clear Air and Clouds  

Science Conference Proceedings (OSTI)

The realization that clouds are diluted by the entrainment of dry air from outside the cloud boundaries began more than 40 years ago. Cloud-top entrainment was first clearly recognized by Squires in 1958. Warner and Squires showed that the ...

James W. Telford; Steven K. Chai

1993-04-01T23:59:59.000Z

484

Cloud service selection based on variability modeling  

Science Conference Proceedings (OSTI)

The selection among Cloud services is a recent problem in research and practice. The diversity of decision-relevant criteria, configurability of Cloud services and the need to involve human decision-makers require holistic support through models, methodologies ... Keywords: cloud service selection, decision-making, feature modeling, variability modeling

Erik Wittern; Jörn Kuhlenkamp; Michael Menzel

2012-11-01T23:59:59.000Z

485

The CloudBrowser web application framework  

Science Conference Proceedings (OSTI)

CloudBrowser is a web application framework that supports the development of rich Internet applications whose entire user interface and application logic resides on the server, while all client/server communication is provided by the framework. CloudBrowser ... Keywords: ajax, cloud applications, paas, remote display, server-centric, web application framework

Brian McDaniel; Godmar Back

2012-10-01T23:59:59.000Z

486

Efficient Mushroom Cloud Simulation on GPU  

Science Conference Proceedings (OSTI)

In this paper, we present a method to simulate the Mushroom Cloud efficient on GPU using advanced particle system, and our particle system is a state-preserving simulation system. We provide the visual-only model of Mushroom Cloud and we divide the Mushroom ... Keywords: Floating Point Textures, GPU (Graphics Processing Unit), Mushroom Cloud simulation, particle system, state-preserving simulation

Xingquan Cai; Jinhong Li; Zhitong Su

2008-06-01T23:59:59.000Z

487

Cloud-Cover Distributions and Correlations  

Science Conference Proceedings (OSTI)

Observations of cloud cover (in oktas or tenths) by ground-based observers have been studied to investigate the distribution of cloud-cover amounts and the correlation of cloud cover in time and space. The correlation between observations at the ...

P. A. Jones

1992-07-01T23:59:59.000Z

488

Large scale data analytics on clouds  

Science Conference Proceedings (OSTI)

We summarize important overall issues affecting use of clouds to support Data Science. We describe the mapping of different applications to HPCC and Cloud systems and the architecture that support data analytics that is interoperable between these architectures. Keywords: clouds, data science, exascale, hpcc, iterative mapreduce, mapreduce, mpi, programming paradigms

Geoffrey C. Fox

2012-10-01T23:59:59.000Z

489

Adaptive resource configuration for Cloud infrastructure management  

Science Conference Proceedings (OSTI)

To guarantee the vision of Cloud Computing QoS goals between the Cloud provider and the customer have to be dynamically met. This so-called Service Level Agreement (SLA) enactment should involve little human-based interaction in order to guarantee the ... Keywords: Autonomic Computing, Case-Based Reasoning, Cloud Computing, Knowledge management, Resource management, Rule-based system

Michael Maurer; Ivona Brandic; Rizos Sakellariou

2013-02-01T23:59:59.000Z

490

Arctic Ocean Warming Contributes to Reduced Polar Ice Cap  

Science Conference Proceedings (OSTI)

Analysis of modern and historical observations demonstrates that the temperature of the intermediate-depth (150–900 m) Atlantic water (AW) of the Arctic Ocean has increased in recent decades. The AW warming has been uneven in time; a local 1°C ...

Igor V. Polyakov; Leonid A. Timokhov; Vladimir A. Alexeev; Sheldon Bacon; Igor A. Dmitrenko; Louis Fortier; Ivan E. Frolov; Jean-Claude Gascard; Edmond Hansen; Vladimir V. Ivanov; Seymour Laxon; Cecilie Mauritzen; Don Perovich; Koji Shimada; Harper L. Simmons; Vladimir T. Sokolov; Michael Steele; John Toole

2010-12-01T23:59:59.000Z

491

Interannual variability of arctic landfast ice between 1976 and 2007  

Science Conference Proceedings (OSTI)

Analysis of weekly sea ice charts produced by the U.S. National Ice Center from 1976 to 2007 indicates large interannual variations in the averaged winter landfast ice extent around the Arctic Basin. During the 32-year period of the record, ...

Yanling Yu; Harry Stern; Charles Fowler; Florence Fetterer; James Maslanik

492

On the circulation of Atlantic Water in the Arctic Ocean  

Science Conference Proceedings (OSTI)

An idealized eddy-resolving numerical model and an analytic three-layer model are used to develop ideas about what controls the circulation of Atlantic Water in the Arctic Ocean. The numerical model is forced with a surface heat flux, uniform ...

Michael A. Spall

493

Observation of Ice Crystal Formation in Lower Arctic Atmosphere  

Science Conference Proceedings (OSTI)

Clear sky ice crystals or diamond dust displays are observed in polar regions, both remote and populated; when the temperature falls to ?20°C and where abundant sources of water vapor are present. In remote areas of the Arctic, these ice crystals ...

Takeshi Ohtake; Kolf Jayaweera; Ken-Ichi Sakurai

1982-12-01T23:59:59.000Z

494

Hafnium isotopes in Arctic Ocean water Bettina Zimmermann a  

E-Print Network (OSTI)

-GEOMAR, 24148 Kiel, Germany d Laboratory for Isotope Geology, Swedish Museum of Natural History, Box 50007, SEHafnium isotopes in Arctic Ocean water Bettina Zimmermann a , Don Porcelli b,*, Martin Frank c-104 05 Stockholm, Sweden e Department of Geology, Wayne State University, Detroit, MI 48202, USA f

Baskaran, Mark

495

The Water and Energy Budget of the Arctic Atmosphere  

Science Conference Proceedings (OSTI)

The Arctic plays a major role in the global circulation, and its water and energy budget is not as well explored as that in other regions of the world. The aim of this study is to calculate the climatological mean water and energy fluxes ...

Tido Semmler; Daniela Jacob; K. Heinke Schlünzen; Ralf Podzun

2005-07-01T23:59:59.000Z

496

The Gravity Wave–Arctic Stratospheric Vortex Interaction  

Science Conference Proceedings (OSTI)

Four hundred and twenty-two nights of stratospheric gravity wave observations were obtained with a Rayleigh lidar in the High Arctic at Eureka (80°N, 86°W) during six wintertime measurement campaigns between 1992/93 and 1997/98. The measurements ...

Thomas J. Duck; James A. Whiteway; Allan I. Carswell

2001-12-01T23:59:59.000Z

497

Estimation of Heat and Mass Fluxes Over Arctic Leads  

Science Conference Proceedings (OSTI)

Recent work on the turbulent transfer of scalar quantities following a step increase in