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

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...

2

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

3

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

4

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

5

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

6

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

7

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

8

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

9

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

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

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

12

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

SciTech Connect

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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...

20

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

42

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

43

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

44

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

45

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

46

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

47

Cloud Microphysics of the Giant Planets  

Science Conference Proceedings (OSTI)

The predominant cloud microphysical processes for the atmospheres of the giant planets are determined by a comparison of their characteristic time constants. These results are an extension of the earlier microphysical modeling by Rossow to other ...

Barbara E. Carlson; William B. Rossow; Glenn S. Orton

1988-07-01T23:59:59.000Z

48

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

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

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

57

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.

58

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

59

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...

60

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

62

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

63

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

64

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

65

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

66

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

67

Quantification of Cloud Microphysical Parameterization Uncertainty Using Radar Reflectivity  

Science Conference Proceedings (OSTI)

Uncertainty in cloud microphysical parameterization—a leading order contribution to numerical weather prediction error—is estimated using a Markov chain Monte Carlo (MCMC) algorithm. An inversion is performed on 10 microphysical parameters using ...

Marcus van Lier-Walqui; Tomislava Vukicevic; Derek J. Posselt

2012-11-01T23:59:59.000Z

68

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.

69

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...

70

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

71

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

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(DAP) - Evelyne Richard, Hans-Stefan Bauer * Aerosol and Cloud Microphysics (ACM) - Chairs: Susanne Crewell, Dave Turner, Stephen Mobbs ACM Scientific Questions * What...

72

Drizzle in Stratiform Boundary Layer Clouds. Part II: Microphysical Aspects  

Science Conference Proceedings (OSTI)

This is the second of two observational papers examining drizzle in stratiform boundary layer clouds. Part I details the vertical and horizontal structure of cloud and drizzle parameters, including some bulk microphysical variables. In this paper,...

R. Wood

2005-09-01T23:59:59.000Z

73

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

74

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

75

Posters Cloud Microphysical and Radiative Properties Measured  

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7 7 Posters Cloud Microphysical and Radiative Properties Measured by Combined Lidar, Radar, and Infrared Radiometer W. L. Eberhard and J. M. Intrieri National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado K. P. Chan and G. Feingold Cooperative Institute for Research in Environmental Sciences Boulder, Colorado also an order of magnitude smaller. These features make simple approximations in scattering calculations adequate for some applications, e.g., Eberhard (1993a). They also provide some unique capabilities, especially the technique described below for measuring drop sizes. One of the four IDP tasks is to characterize cloud signatures obtained by CO 2 lidar. For instance, our earlier work discovered that depolarization from ice particles was almost

76

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

77

Simulation of Cloud Microphysical and Chemical Processes Using a Multicomponent Framework. Part II: Microphysical Evolution of a Wintertime Orographic Cloud  

Science Conference Proceedings (OSTI)

A detailed microphysical model is used to simulate the formation of wintertime orographic clouds in a two-dimensional domain under steady-state conditions. Mass contents and number concentrations of both liquid- and ice-phase cloud particles are ...

Jen-Ping Chen; Dennis Lamb

1999-07-01T23:59:59.000Z

78

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

79

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

80

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

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

ProductsAtmospheric State, Cloud Microphysics & ProductsAtmospheric State, Cloud Microphysics & Radiative Flux Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Atmospheric State, Cloud Microphysics & Radiative Flux 1997.01.01 - 2010.12.31 Site(s) NSA SGP TWP General Description This data product contains atmospheric thermodynamics, cloud properties, radiative fluxes and radiative heating rates. The data represent a characterization of the physical state of the atmospheric column compiled on a five-minute temporal and 90m vertical grid. Sources for this information include raw measurements, cloud property and radiative retrievals, retrievals and derived variables from other third-party sources, and radiative calculations using the derived quantities.

82

Simulation of Cloud Microphysical and Chemical Processes Using a Multicomponent Framework. Part I: Description of the Microphysical Model  

Science Conference Proceedings (OSTI)

A detailed microphysical and chemical cloud model has been developed to investigate the redistribution of atmospheric trace substances through cloud processes. A multicomponent categorization scheme is used to group cloud particles into different ...

Jen-Ping Chen; Dennis Lamb

1994-09-01T23:59:59.000Z

83

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

84

Cirrus Cloud Ice Water Content Radar Algorithm Evaluation Using an Explicit Cloud Microphysical Model  

Science Conference Proceedings (OSTI)

A series of cirrus cloud simulations performed using a model with explicit cloud microphysics is applied to testing ice water content retrieval algorithms based on millimeter-wave radar reflectivity measurements. The simulated ice particle size ...

Kenneth Sassen; Zhien Wang; Vitaly I. Khvorostyanov; Graeme L. Stephens; Angela Bennedetti

2002-06-01T23:59:59.000Z

85

Microphysical Structure and Evolution of a Central Sierra Nevada Orographic Cloud System  

Science Conference Proceedings (OSTI)

This paper describes complex microphysical interactions observed within an orographic cloud system over the central Sierra Nevada of California. Measurements of the physical structure and microphysical characteristics of this cloud system were ...

Robert M. Rauber

1992-01-01T23:59:59.000Z

86

Empirical relationship between entrainment rate and microphysics in cumulus clouds  

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Empirical Empirical relationship between entrainment rate and microphysics in cumulus clouds Chunsong Lu, 1,2 Shengjie Niu, 1 Yangang Liu, 2 and Andrew M. Vogelmann 2 Received 16 March 2013; accepted 3 April 2013; published 22 May 2013. [1] The relationships between fractional entrainment rate and key microphysical quantities (e.g., liquid water content, droplet number concentration, volume mean radius, and standard deviation of cloud droplet size distributions) in shallow cumuli are empirically examined using in situ aircraft observations from the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign over the Atmospheric Radiation Measurement Southern Great Plains site. The results show that the microphysical quantities examined generally exhibit strong relationships with

87

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

88

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

89

A Warm-Bin–Cold-Bulk Hybrid Cloud Microphysical Model  

Science Conference Proceedings (OSTI)

This study describes a newly developed bin–bulk hybrid cloud microphysical model named MSSG-Bin, which has been implemented in the Multi-Scale Simulator for the Geoenvironment (MSSG). In the hybrid approach, a spectral bin scheme is used for ...

Ryo Onishi; Keiko Takahashi

2012-05-01T23:59:59.000Z

90

Influence of Rain-Rate Initialization, Cloud Microphysics, and Cloud Torques on Hurricane Intensity  

Science Conference Proceedings (OSTI)

This study examines the impact of rain-rate initialization (RINIT), microphysical modifications, and cloud torques (in the context of angular momentum) on hurricane intensity forecasts using a mesoscale model [the Advanced Research Weather ...

S. Pattnaik; C. Inglish; T. N. Krishnamurti

2011-02-01T23:59:59.000Z

91

Numerical Simulation of Cloud–Clear Air Interfacial Mixing: Effects on Cloud Microphysics  

Science Conference Proceedings (OSTI)

This paper extends the previously published numerical study of Andrejczuk et al. on microscale cloud–clear air mixing. Herein, the primary interest is on microphysical transformations. First, a convergence study is performed—with well-resolved ...

Miroslaw Andrejczuk; Wojciech W. Grabowski; Szymon P. Malinowski; Piotr K. Smolarkiewicz

2006-12-01T23:59:59.000Z

92

The Sensitivity of Radiative Fluxes to Parameterized Cloud Microphysics  

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

Sensitivity of Radiative Fluxes to Sensitivity of Radiative Fluxes to Parameterized Cloud Microphysics S. F. Iacobellis and R. C. J. Somerville Scripps Institution of Oceanography University of California San Diego, California G. M. McFarquhar University of Illinois at Urbana-Champaign Urbana, Illinois D. L. Mitchell Desert Research Institute Las Vegas, Nevada Introduction We have used a single-column model (SCM) to examine the sensitivity of fundamental quantities such as atmospheric radiative heating rates and surface and top of atmosphere (TOA) radiative fluxes to various parameterizations of clouds and cloud microphysics. When an SCM, which consists of one isolated column of a global atmospheric model, is forced with observational estimates of horizontal advection terms, the parameterizations within the SCM produce time-dependent fields which can be

93

Sensitivity of Radiative Fluxes and Heating Rates to Cloud Microphysics  

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

Sensitivity of Radiative Fluxes and Heating Sensitivity of Radiative Fluxes and Heating Rates to Cloud Microphysics S. F. Iacobellis and R. C. J. Somerville Scripps Institution of Oceanography University of California, San Diego La Jolla, California G. M. McFarquhar University of Illinois at Urbana-Champaign Urbana, Illinois D. L. Mitchell Desert Research Institute Reno, Nevada Introduction A single-column model (SCM) is used to examine the sensitivity of basic quantities such as atmospheric radiative heating rates and surface and top of atmosphere (TOA) radiative fluxes to various parameter- izations of clouds and cloud microphysics. The SCM was run at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains (SGP), Tropical Western Pacific (TWP), and North Slope of Alaska (NSA) sites using forcing data derived from forecast products. The forecast

94

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

95

Satellite Determination of Stratus Cloud Microphysical Properties  

Science Conference Proceedings (OSTI)

Satellite measurements of liquid water path from SSM/I, broadband albedo from ERBE, and cloud characteristics from ISCCP are used to study stratus regions. An average cloud liquid water path of 0.120 ± 0.032 kg m?2 is derived by dividing the ...

Paquita Zuidema; Dennis L. Hartmann

1995-06-01T23:59:59.000Z

96

A PDF-Based Microphysics Parameterization for Simulation of Drizzling Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

Formulating the contribution of subgrid-scale (SGS) variability to microphysical processes in boundary layer and deep convective cloud parameterizations is a challenging task because of the complexity of microphysical processes and the lack of ...

Anning Cheng; Kuan-Man Xu

2009-08-01T23:59:59.000Z

97

The Simulation of a Convective Cloud in a 3D Model with Explicit Microphysics. Part II: Dynamical and Microphysical Aspects of Cloud Merger  

Science Conference Proceedings (OSTI)

The development and merger of pairs of convective clouds in a shear-free environment were simulated in an explicit microphysical cloud model. The occurrence or nonoccurrence of updraft merger and the timing of merger depended critically on the ...

Yefim L. Kogan; Alan Shapiro

1996-09-01T23:59:59.000Z

98

Liquid and Ice Cloud Microphysics in the CSU General Circulation Model. Part 1: Model Description and Simulated Microphysical Processes  

Science Conference Proceedings (OSTI)

Microphysical processes responsible for the formation and dissipation of water and ice clouds have been incorporated into the Colorado State University General Circulation Model in order to 1) yield a more physically based representation of the ...

Laura D. Fowler; David A. Randall; Steven A. Rutledge

1996-03-01T23:59:59.000Z

99

In Situ Observations of Cirrus Cloud Microphysical Properties Using the Counterflow Virtual Impactor  

Science Conference Proceedings (OSTI)

This study presents a new technique for making in situ measurements of cirrus cloud microphysical properties. Sampling of cirrus clouds was performed using a counterflow virtual impactor (CVI). The CVI was used to sample cloud elements larger ...

K. B. Noone; K. J. Noone; J. Heintzenberg; J. Ström; J. A. Ogren

1993-06-01T23:59:59.000Z

100

A comparison of cloud microphysical quantities with forecasts from cloud prediction models  

SciTech Connect

Numerical weather prediction models (ECMWF, NCEP) are evaluated using ARM observational data collected at the Southern Great Plains (SGP) site. Cloud forecasts generated by the models are compared with cloud microphysical quantities, retrieved using a variety of parameterizations. Information gained from this comparison will be utilized during the FASTER project, as models are evaluated for their ability to reproduce fast physical processes detected in the observations. Here the model performance is quantified against the observations through a statistical analysis. Observations from remote sensing instruments (radar, lidar, radiometer and radiosonde) are used to derive the cloud microphysical quantities: ice water content, liquid water content, ice effective radius and liquid effective radius. Unfortunately, discrepancies in the derived quantities arise when different retrieval schemes are applied to the observations. The uncertainty inherent in retrieving the microphysical quantities using various retrievals is estimated from the range of output microphysical values. ARM microphysical retrieval schemes (Microbase, Mace) are examined along with the CloudNet retrieval processing of data from the ARM sites for this purpose. Through the interfacing of CloudNet and “ARM” processing schemes an ARMNET product is produced and employed as accepted observations in the assessment of cloud model predictions.

Dunn, M.; Jensen, M.; Hogan, R.; O’Connor, E.; Huang, D.

2010-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

102

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

103

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

104

Microphysical and Radar Observations of Seeded and Nonseeded Continental Cumulus Clouds  

Science Conference Proceedings (OSTI)

Controlled cloud seeding experiments were conducted near Bethlehem, South Africa during the summer of 1984–85. The experimental unit was the semi-isolated cumulus congestus cloud. Microphysical measurements were obtained by three instrumented ...

T. W. Krauss; R. T. Bruintjes; J. Verlinde

1987-05-01T23:59:59.000Z

105

Competition of Precipitation Particles in a Model with Parameterized Cloud Microphysics  

Science Conference Proceedings (OSTI)

The nonlinear open system cloud is analyzed in this basic study in the context of the theory of self-organization. Emphasis is placed on the microphysical processes of riming, accretion, and sedimentation in a supercooled cloud containing several ...

Ulrike Wacker

1995-07-01T23:59:59.000Z

106

Variability of Microphysical Parameters in High-Altitude Ice Clouds: Results of the Remote Sensing Method  

Science Conference Proceedings (OSTI)

The remote sensing method for retrieving vertical profiles of microphysical parameters in ice clouds from ground-based measurements taken by the Doppler radar and IR radiometer was applied to several cloud cases observed during different field ...

Sergey Y. Matrosov

1997-06-01T23:59:59.000Z

107

A Binned Approach to Cloud-Droplet Riming Implemented in a Bulk Microphysics Model  

Science Conference Proceedings (OSTI)

This paper presents the development and application of a binned approach to cloud-droplet riming within a bulk microphysics model. This approach provides a more realistic representation of collision–coalescence that occurs between ice and cloud ...

Stephen M. Saleeby; William R. Cotton

2008-02-01T23:59:59.000Z

108

An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds  

Science Conference Proceedings (OSTI)

The large horizontal extent, with its location in the cold upper troposphere, and ice composition make cirrus clouds important modulators of the Earth's radiation budget and climate. Cirrus cloud microphysical properties are difficult to measure ...

Jennifer M. Comstock; Sally A. McFarlane; Robert d'Entremont; Daniel DeSlover; David D. Turner; Gerald G. Mace; Sergey Y. Matrosov; Matthew D. Shupe; Patrick Minnis; David Mitchell; Kenneth Sassen; Zhien Wang

2007-02-01T23:59:59.000Z

109

Microphysical and Radiative Effects of Ice Clouds on Tropical Equilibrium States: A Two-Dimensional Cloud-Resolving Modeling Study  

Science Conference Proceedings (OSTI)

The microphysical and radiative effects of ice clouds on tropical equilibrium states are investigated based on three two-dimensional cloud-resolving simulations imposed by zero vertical velocity and time-invariant zonal wind and sea surface ...

Fan Ping; Zhexian Luo; Xiaofan Li

2007-07-01T23:59:59.000Z

110

In Situ Observations of the Microphysical Properties of Wave, Cirrus, and Anvil Clouds. Part I: Wave Clouds  

Science Conference Proceedings (OSTI)

The microphysical properties of wave clouds based on data collected during 17 missions flown by a Learjet research aircraft are presented and discussed. This extensive dataset expands upon previous aircraft studies of wave clouds and introduces ...

Brad A. Baker; R. Paul Lawson

2006-12-01T23:59:59.000Z

111

In Situ Observations of the Microphysical Properties of Wave, Cirrus, and Anvil Clouds. Part II: Cirrus Clouds  

Science Conference Proceedings (OSTI)

A Learjet research aircraft was used to collect microphysical data, including cloud particle imager (CPI) measurements of ice particle size and shape, in 22 midlatitude cirrus clouds. The dataset was collected while the aircraft flew 104 ...

R. Paul Lawson; Brad Baker; Bryan Pilson; Qixu Mo

2006-12-01T23:59:59.000Z

112

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

113

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

SciTech Connect

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

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

2013-07-01T23:59:59.000Z

114

Retrieval of Thermal and Microphysical Variables in Observed Convective Storms. Part II: Sensitivity of Cloud Processes to Variation of the Microphysical Parameterization  

Science Conference Proceedings (OSTI)

The hydrometeor content and thermal fields in a thunderstorm are estimated from a three-dimensional kinematic cloud model employing Doppler wind fields and parameterized microphysical processes. The sensitivity of the cloud model calculations to ...

Conrad L. Ziegler

1988-03-01T23:59:59.000Z

115

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

116

Implementation of the Daytime Cloud Optical and Microphysical Properties Algorithm (DCOMP) in PATMOS-x  

Science Conference Proceedings (OSTI)

This paper describes the daytime cloud optical and microphysical properties (DCOMP) retrieval for the Pathfinder Atmosphere’s Extended (PATMOS-x) climate dataset. Within PATMOS-x, DCOMP is applied to observations from the Advanced Very High ...

Andi Walther; Andrew K. Heidinger

2012-07-01T23:59:59.000Z

117

Modeling of Stratocumulus Cloud Layers in a Large Eddy Simulation Model with Explicit Microphysics  

Science Conference Proceedings (OSTI)

A new large eddy simulation (LES) stratocumulus cloud model with an explicit formulation of micro-physical processes has been developed, and the results from three large eddy simulations are presented to illustrate the effects of the ...

Y. L. Kogan; M. P. Khairoutdinov; D. K. Lilly; Z. N. Kogan; Qingfu Liu

1995-08-01T23:59:59.000Z

118

Probing Finescale Dynamics and Microphysics of Clouds with Helicopter-Borne Measurements  

Science Conference Proceedings (OSTI)

Helicopter-based measurements provide an opportunity for probing the finescale dynamics and microphysics of clouds simultaneously in space and time. Due to the low true air speed compared with research aircraft, a helicopter allows for ...

Holger Siebert; Katrin Lehmann; Manfred Wendisch; Harald Franke; Rolf Maser; Dieter Schell; Ewe Wei Saw; Raymond A. Shaw

2006-12-01T23:59:59.000Z

119

Mesoscale Organization and Cloud Microphysics in a Bay of Bengal Depression  

Science Conference Proceedings (OSTI)

Airborne radar and cloud microphysical data were obtained throughout a monsoon depression observed over the Bay of Bengal on 3–8 July 1979 during the Summer Monsoon Experiment of the Global Atmospheric Research Programme. The precipitation in the ...

Robert A. Houze Jr.; Dean D. Churchill

1987-07-01T23:59:59.000Z

120

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Retrieval of Vertical Profiles of Cirrus Cloud Microphysical Parameters from Doppler Radar and Infrared Radiometer Measurements  

Science Conference Proceedings (OSTI)

This paper describes a new method to retrieve vertical profiles of the parameters of cirrus cloud microphysics that are important for the estimation of climatic feedback. These parameters are the particle characteristic size and ice mass content. ...

S. Y. Matrosov; B. W. Orr; R. A. Kropfli; J. B. Snider

1994-05-01T23:59:59.000Z

122

The Role of Background Cloud Microphysics in the Radiative Formation of Ship Tracks  

Science Conference Proceedings (OSTI)

The authors investigate the extent to which the contrast brightness of ship tracks, that is, the relative change in observed solar reflectance, in visible and near-infrared imagery can be explained by the microphysics of the background cloud in ...

S. Platnick; P. A. Durkee; K. Nielsen; J. P. Taylor; S.-C. Tsay; M. D. King; R. J. Ferek; P. V. Hobbs; J. W. Rottman

2000-08-01T23:59:59.000Z

123

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

124

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

125

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

126

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

127

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

128

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

129

Microphysical and Dynamical Influences on Cirrus Cloud Optical Depth Distributions  

SciTech Connect

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

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

2005-03-18T23:59:59.000Z

130

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

131

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

132

Obtaining Best Estimates for the Microphysical and Radiative Properties of Tropical Ice Clouds from TWP-ICE In Situ Microphysical Observations  

Science Conference Proceedings (OSTI)

Best estimates of the bulk microphysical and radiative properties (ice water content, visible extinction, effective radius, and total concentration) are derived for three case studies of tropical ice clouds sampled during the Tropical Warm Pool ...

A. Protat; G. M. McFarquhar; J. Um; J. Delanoė

2011-04-01T23:59:59.000Z

133

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

134

Sensitivity of Simulated Global Climate to Perturbations in Low Cloud Microphysical Properties. Part II: Spatially Localized Perturbations  

Science Conference Proceedings (OSTI)

The sensitivity of the global climate to spatially localized (20°–70°N) perturbations in the microphysical properties of low clouds is investigated using a general circulation model coupled to a mixed layer ocean with fixed cloud distributions. ...

C-T. Chen; V. Ramaswamy

1996-11-01T23:59:59.000Z

135

Nucleation Processes in Deep Convection Simulated by a Cloud-System-Resolving Model with Double-Moment Bulk Microphysics  

Science Conference Proceedings (OSTI)

A novel type of limited double-moment scheme for bulk microphysics is presented here for cloud-system-resolving models (CSRMs). It predicts the average size of cloud droplets and crystals, which is important for representing the radiative impact ...

Vaughan T. J. Philips; Leo J. Donner; Stephen T. Garner

2007-03-01T23:59:59.000Z

136

Liquid and Ice Cloud Microphysics in the CSU General Circulation Model. Part III: Sensitivity to Modeling Assumptions  

Science Conference Proceedings (OSTI)

The inclusion of cloud microphysical processes in general circulation models makes it possible to study the multiple interactions among clouds, the hydrological cycle, and radiation. The gaps between the temporal and spatial scales at which such ...

Laura D. Fowler; David A. Randall

1996-03-01T23:59:59.000Z

137

Microphysical Effects of Wintertime Cloud Seeding with Silver Iodide over the Rocky Mountains. Part I: Experimental Design and Instrumentation  

Science Conference Proceedings (OSTI)

A series of winter orographic cloud seeding experiments is described in which the seeding agent and associated changes in cloud microphysics are monitored to within 300 m of the target areas (Montana and Colorado), and at the surface (Colorado ...

Arlin B. Super; Bruce A. Boe; Edmond W. Holroyd III; James A. Heimbach Jr.

1988-10-01T23:59:59.000Z

138

Cloud microphysical properties retrieved from downwelling infrared radiance measurements made at Eureka, Nunavut, Canada (2006-2009)  

Science Conference Proceedings (OSTI)

The radiative properties of clouds are related to cloud microphysical and optical properties, including water path, optical depth, particle size, and thermodynamic phase. Ground-based observations provide high quality, long-term, continuous ...

Christopher J. Cox; David D. Turner; Penny M. Rowe; Matthew D. Shupe; Von P. Walden

139

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

E-Print Network (OSTI)

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

Xue, Ming

140

Simulation of microphysical structure associated with tropical cloud clusters using mesoscale model and comparison with TRMM observations  

Science Conference Proceedings (OSTI)

An attempt has been made in the present study to examine the microphysical structure of a non-squall Tropical Cloud Cluster (TCC). Three-dimensional model simulations of cloud microphysical structure associated with a non-squall TCC occurred on 26 October ...

S. Abhilash; K. Mohankumar; S. Das

2008-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

142

The Role of Cloud Microphysics Parameterization in the Simulation of Mesoscale Convective System Clouds and Precipitation in the Tropical Western Pacific  

Science Conference Proceedings (OSTI)

This paper presents a detailed analysis of convection-permitting cloud simulations, aimed at increasing the understanding of the role of parameterized cloud microphysics in the simulation of mesoscale convective systems (MCSs) in the tropical ...

K. Van Weverberg; A. M. Vogelmann; W. Lin; E. P. Luke; A. Cialella; P. Minnis; M. Khaiyer; E. R. Boer; M. P. Jensen

2013-04-01T23:59:59.000Z

143

Microphysics of Premonsoon and Monsoon Clouds as Seen from In Situ Measurements during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX)  

Science Conference Proceedings (OSTI)

Analysis of the microphysical structure of deep convective clouds using in situ measurements during the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) over the Indian peninsular region is presented. It is shown that ...

Thara V. Prabha; A. Khain; R. S. Maheshkumar; G. Pandithurai; J. R. Kulkarni; M. Konwar; B. N. Goswami

2011-09-01T23:59:59.000Z

144

Soot microphysical effects on liquid clouds, a multi-model investigation  

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

Soot microphysical effects on liquid clouds, a multi-model investigation Soot microphysical effects on liquid clouds, a multi-model investigation Title Soot microphysical effects on liquid clouds, a multi-model investigation Publication Type Journal Article Year of Publication 2011 Authors Koch, Dorothy M., Yves Balkanski, Susanne E. Bauer, Richard C. Easter, Sylvaine Ferrachat, Steven J. Ghan, Corinna Hoose, Trond Iversen, Alf KirkevĆ„g, Jon E. KristjĆ”nsson, Xiaohong Liu, Ulrike Lohmann, Surabi Menon, Johannes Quaas, Michael Schulz, Ƙyvind Seland, Toshihiko Takemura, and N. Yan Journal Atmospheric Chemistry and Physics Volume 11 Pagination 1051-1064 Abstract We use global models to explore the microphysical effects of carbonaceous aerosols on liquid clouds. Although absorption of solar radiation by soot warms the atmosphere, soot may cause climate cooling due to its contribution to cloud condensation nuclei (CCN) and therefore cloud brightness. Six global models conducted three soot experiments; four of the models had detailed aerosol microphysical schemes. The average cloud radiative response to biofuel soot (black and organic carbon), including both indirect and semi-direct effects, is -0.11 Wm-2, comparable in size but opposite in sign to the respective direct effect. In a more idealized fossil fuel black carbon experiment, some models calculated a positive cloud response because soot provides a deposition sink for sulfuric and nitric acids and secondary organics, decreasing nucleation and evolution of viable CCN. Biofuel soot particles were also typically assumed to be larger and more hygroscopic than for fossil fuel soot and therefore caused more negative forcing, as also found in previous studies. Diesel soot (black and organic carbon) experiments had relatively smaller cloud impacts with five of the models <Ā±0.06 Wm-2 from clouds. The results are subject to the caveats that variability among models, and regional and interrannual variability for each model, are large. This comparison together with previously published results stresses the need to further constrain aerosol microphysical schemes. The non-linearities resulting from the competition of opposing effects on the CCN population make it difficult to extrapolate from idealized experiments to likely impacts of realistic potential emission changes.

145

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

SciTech Connect

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

Dunn, M; Johnson, K; Jensen, M

2011-05-31T23:59:59.000Z

146

Microphysical Effects of Seeding Wintertime Stratiform Clouds Near the Sierra Nevada Mountains  

Science Conference Proceedings (OSTI)

The microphysical consequences of seeding stratiform clouds near the Sierra Nevada Mountains are examined. Airborne seeding was conducted with droppable AgI flares released every 250 m and with dry ice pellets released at a rate of 0.1 g m?1 into ...

Ronald E. Stewart; John D. Marwitz

1982-06-01T23:59:59.000Z

147

Aerosol Impacts on Clouds and Precipitation in Eastern China: Results from Bin and Bulk Microphysics  

Science Conference Proceedings (OSTI)

Using the Weather Research and Forecasting (WRF) model coupled with a 3 spectral-bin microphysics ('SBM') and measurements from the Atmospheric Radiation 4 Measurement (ARM) Mobile Facility field campaign in China (AMF-China), the authors 5 examine aerosol indirect effects (AIE) in the typical cloud regimes of the warm and cold 6 seasons in Southeast China: deep convective clouds (DCC) and stratus clouds (SC), 7 respectively. Comparisons with a two-moment bulk microphysics ('Bulk') are performed 8 to gain insights for improving bulk schemes in estimating AIE in weather and climate 9 simulations. For the first time, measurements of aerosol and cloud properties acquired in 10 China are used to evaluate model simulations to better understand AIE in China. It is 11 found that changes in cloud condensation nuclei (CCN) concentration significantly 12 change the timing of storms, the spatial and temporal distributions of precipitation, the 13 frequency distribution of precipitation rate, as well as cloud base and top heights for the 14 DCC, but not for the SC. CCN increase cloud droplet number (Nc) and mass 15 concentrations, decrease raindrop number concentration (Nr), and delay the onset of 16 precipitation. It is indicated much higher Nc and the opposite CCN effects on convection 17 and heavy rain with Bulk compared to SBM stem from the fixed CCN prescribed in Bulk. 18 CCN have a significant effect on ice microphysical properties with SBM but not Bulk 19 and different condensation/deposition freezing parameterizations employed could be the 20 main reason. This study provided insights to further improve the bulk scheme to better 21 account for aerosol-cloud interactions in regional and global climate simulations, which 22 will be the focus for a follow-on paper.

Fan, Jiwen; Leung, Lai-Yung R.; Li, Zhanqing; Morrison, H.; Chen, Hongbin; Zhou, Yuquan; Qian, Yun; Wang, Yuan

2012-01-19T23:59:59.000Z

148

Understanding the Importance of Microphysics and Macrophysics for Warm Rain in Marine Low Clouds. Part I: Satellite Observations  

Science Conference Proceedings (OSTI)

The importance of macrophysical variables [cloud thickness, liquid water path (LWP)] and microphysical variables (effective radius re, effective droplet concentration Neff) on warm drizzle intensity and frequency across the tropics and subtropics ...

Terence L. Kubar; Dennis L. Hartmann; Robert Wood

2009-10-01T23:59:59.000Z

149

Understanding the Relationships between Lightning, Cloud Microphysics, and Airborne Radar-Derived Storm Structure during Hurricane Karl (2010)  

Science Conference Proceedings (OSTI)

This study explores relationships between lightning, cloud microphysics, and tropical cyclone (TC) storm structure in Hurricane Karl (16 September 2010) using data collected by the NASA DC-8 and Global Hawk (GH) aircraft during NASA’s Genesis and ...

Brad Reinhart; Henry Fuelberg; Richard Blakeslee; Douglas Mach; Andrew Heymsfield; Aaron Bansemer; Stephen L. Durden; Simone Tanelli; Gerald Heymsfield; Bjorn Lambrigtsen

150

Use of Cloud Model Microphysics for Passive Microwave-Based Precipitation Retrieval: Significance of Consistency between Model and Measurement Manifolds  

Science Conference Proceedings (OSTI)

Precipitation estimation from passive microwave radiometry based on physically based profile retrieval algorithms must be aided by a microphysical generator providing structure information on the lower portions of the cloud, consistent with the ...

Giulia Panegrossi; Stefano Dietrich; Frank S. Marzano; Alberto Mugnai; Eric A. Smith; Xuwu Xiang; Gregory J. Tripoli; Pao K. Wang; J. P. V. Poiares Baptista

1998-05-01T23:59:59.000Z

151

Rain Production in Convective Clouds As Simulated in an Axisymmetric Model with Detailed Microphysics. Part I: Description of the Model  

Science Conference Proceedings (OSTI)

A hydrodynamic nonhydrostatic anelastic numerical model of an axisymmetric convective cloud is described in which the microphysical processes are treated in detail for different species of hydrometeors: drops. ice crystals, graupel, and snow ...

Tamir Reisin; Zev Levin; Shalva Tzivion

1996-02-01T23:59:59.000Z

152

A New Double-Moment Microphysics Parameterization for Application in Cloud and Climate Models. Part I: Description  

Science Conference Proceedings (OSTI)

A new double-moment bulk microphysics scheme predicting the number concentrations and mixing ratios of four hydrometeor species (droplets, cloud ice, rain, snow) is described. New physically based parameterizations are developed for simulating ...

H. Morrison; J. A. Curry; V. I. Khvorostyanov

2005-06-01T23:59:59.000Z

153

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

154

Retrieval of Cloud Microphysical Properties from MODIS and AIRS  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) measurements from the NASA Earth Observing System Aqua satellite enable global monitoring of the distribution of clouds during day and night. ...

Jun Li; Hung-Lung Huang; Chian-Yi Liu; Ping Yang; Timothy J. Schmit; Heli Wei; Elisabeth Weisz; Li Guan; W. Paul Menzel

2005-10-01T23:59:59.000Z

155

A Global Determination of Cloud Microphysics with AVHRR Remote Sensing  

Science Conference Proceedings (OSTI)

An algorithm is developed for determining the cloud optical thickness and effective particle radius simultaneously on a global scale using Advanced Very High Resolution Radiometer (AVHRR) multispectral radiance data. In the algorithm, the ...

Kazuaki Kawamoto; Teruyuki Nakajima; Takashi Y. Nakajima

2001-05-01T23:59:59.000Z

156

A Balloon-Borne Continuous Cloud Particle Replicator for Measuring Vertical Profiles of Cloud Microphysical Properties: Instrument Design, Performance, and Collection Efficiency Analysis  

Science Conference Proceedings (OSTI)

The performance of a balloon-borne Formvar replicator that measures continuous profiles of cloud microphysical properties is investigated. The replicator measures the small particles (<100-?m diameter) that are undetectable or poorly resolved by ...

Larry M. Miloshevich; Andrew J. Heymsfield

1997-08-01T23:59:59.000Z

157

Characteristics of Correlation Statistics between Droplet Radius and Optical Thickness of Warm Clouds Simulated by a Three-Dimensional Regional-Scale Spectral Bin Microphysics Cloud Model  

Science Conference Proceedings (OSTI)

Three-dimensional downscaling simulations using a spectral bin microphysics (SBM) model were conducted to investigate the effects of aerosol amount and dynamical stabilities of the atmosphere on the correlation statistics between cloud droplet ...

Yousuke Sato; Kentaroh Suzuki; Takamichi Iguchi; In-Jin Choi; Hiroyuki Kadowaki; Teruyuki Nakajima

2012-02-01T23:59:59.000Z

158

An Investigation of Ice Production Mechanisms in Small Cumuliform Clouds Using a 3D Model with Explicit Microphysics. Part II: Case Study of New Mexico Cumulus Clouds  

Science Conference Proceedings (OSTI)

A new 3D model with explicit liquid- and ice-phase microphysics and a detailed treatment of ice nucleation and multiplication processes is applied to study ice formation and evolution in cumulus clouds. Simulation results are compared with in ...

Mikhail Ovtchinnikov; Yefim L. Kogan; Alan M. Blyth

2000-09-01T23:59:59.000Z

159

Microphysics of Venusian Clouds in Rising Tropical Air  

Science Conference Proceedings (OSTI)

As the global distribution of Venusian H2SO4–H2O clouds is strongly related to the global circulation of H2SO4 governed by wind transport and sedimentation of droplets, the circulation of H2SO4 in the Tropics was studied by simultaneously solving ...

Takeshi Imamura; George L. Hashimoto

2001-12-01T23:59:59.000Z

160

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

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

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

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

Use of In Situ Observations to Characterize Use of In Situ Observations to Characterize Cloud Microphysical and Radiative Properties: Application to Climate Studies G. M. McFarquhar and T. Nousiainen Department of Atmospheric Sciences University of Illinois Urbana, Illinois M. S. Timlin, S. F. Iacobellis, and R. C. J. Somerville Scripps Institution of Oceanography La Jolla, California Introduction Cloud radiative feedback is the most important effect determining climate response to human activity. Ice clouds reflect solar radiation and absorb thermal emission from the ground and the lower atmosphere and emit infrared radiation to space. The representation of these processes in models affects future climate predictions and there is much uncertainty in the representation of these processes. The size and

162

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

163

The Characteristics and Distribution of Cloud Water over the Mountains of Northern Colorado during Wintertime Storms. Part II: Spatial Distribution and Microphysical Characteristics  

Science Conference Proceedings (OSTI)

The Physical and microphysical structure of the supercooled water fields in wintertime storms over the Park Range of the northern Colorado Rocky Mountains is examined using aircraft and ground-based measurements. Cloud top, cloud base, and zones ...

Robert M. Rauber; Lewis O. Grant

1986-04-01T23:59:59.000Z

164

Evaluating the Performance of Planetary Boundary Layer and Cloud Microphysical Parameterization Schemes in Convection-Permitting Ensemble Forecasts using Synthetic GOES-13 Satellite Observations  

Science Conference Proceedings (OSTI)

In this study, the ability of several cloud microphysical and planetary boundary layer parameterization schemes to accurately simulate cloud characteristics within 4-km-grid-spacing ensemble forecasts over the contiguous U.S. was evaluated through ...

Rebecca Cintineo; Jason A. Otkin; Ming Xue; Fanyou Kong

165

The Simulation of a Convective Cloud in a 3-D Model With Explicit Microphysics. Part I: Model Description and Sensitivity Experiments  

Science Conference Proceedings (OSTI)

A three-dimensional nonhydrostatic anelastic numerical model of a convective cloud with an explicit description of microphysical processes has been developed. Two distribution functions are considered in the model—one for cloud condensation ...

Yefim L. Kogan

1991-05-01T23:59:59.000Z

166

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

167

Sensitivity Study of Cloud-Resolving Convective Simulations with WRF Using Two Bulk Microphysical Parameterizations: Ice-Phase Microphysics versus Sedimentation Effects  

Science Conference Proceedings (OSTI)

This study examines the relative importance of ice-phase microphysics and sedimentation velocity for hydrometeors in bulk microphysics schemes. The two bulk microphysics schemes having the same number of prognostic water substances, the Weather ...

Song-You Hong; Kyo-Sun Sunny Lim; Ju-Hye Kim; Jeong-Ock Jade Lim; Jimy Dudhia

2009-01-01T23:59:59.000Z

168

Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part II: Cloud Microphysics and Storm Dynamics Interactions  

Science Conference Proceedings (OSTI)

Part I of this paper compares two simulations, one using a bulk and the other a detailed bin microphysical scheme, of a long-lasting, continental mesoscale convective system with leading convection and trailing stratiform region. Diagnostic ...

Xiaowen Li; Wei-Kuo Tao; Alexander P. Khain; Joanne Simpson; Daniel E. Johnson

2009-01-01T23:59:59.000Z

169

The Numerical Simulation of Clouds, Rains and Airflow over the Vosges and Black Forest Mountains: A Meso-? Model with Parameterized Microphysics  

Science Conference Proceedings (OSTI)

A three-dimensional meso-? model with parameterized microphysics is presented. The model is capable of simulating orographically forced clouds, rain, and airflow. Tests using a two-dimensional version confirm the ability of the model to replicate ...

Everett C. Nickerson; Evelyne Richard; Robert Rosset; David R. Smith

1986-02-01T23:59:59.000Z

170

Spatial and Microphysical Characteristics of Low-Ceiling, Temperature-Inverted Clouds in Warm Overrunning and Freezing-Rain Conditions: A Case Study  

Science Conference Proceedings (OSTI)

In-flight microphysical measurements in classical freezing-rain conditions were used to study the vertical and horizontal characteristics of the precipitation and associated low-ceiling, stratiform clouds, which are usually present as overcast in ...

Richard K. Jeck

2011-10-01T23:59:59.000Z

171

Cirrus Cloud Microphysical Property Retrieval Using Lidar and Radar Measurements. Part II: Midlatitude Cirrus Microphysical and Radiative Properties  

Science Conference Proceedings (OSTI)

The lidar–radar algorithm described in Part I of this set of papers is applied to 1000 h of Raman lidar and millimeter wave cloud radar (MMCR) data collected at the Atmospheric Radiation Measurement program Southern Great Plains Clouds and ...

Zhien Wang; Kenneth Sassen

2002-07-01T23:59:59.000Z

172

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

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

Microphysical and Radiative Properties Derived Microphysical and Radiative Properties Derived from MODIS, VIRS, AVHRR, and GMS Data Over the Tropical Western Pacific G. D. Nowicki, M. L. Nordeen, P. W. Heck, D. R. Doelling, and M. M. Khaiyer Analytical Services and Materials, Inc. Hampton, Virginia P. Minnis National Aeronautics and Space Administration Atmospheric Sciences Division Langley Research Center Hampton, Virginia S. Sun-Mack Science Applications International Corporation Hampton, Virginia Introduction Utilization of the geostationary meteorological satellite (GMS) imagery has allowed for the derivation of cloud and radiative properties over the Tropical Western Pacific (TWP) on relatively high spatial and temporal scales. The layered bispectral threshold method (LBTM) has been applied to GMS data

173

Microphysics of Clouds with the Relaxed Arakawa–Schubert Scheme (McRAS). Part II: Implementation and Performance in GEOS II GCM  

Science Conference Proceedings (OSTI)

A prognostic cloud scheme named the Microphysics of Clouds with the Relaxed Arakawa–Schubert Scheme (McRAS) and the Simple Biosphere Model have been implemented in a version of the Goddard Earth Observing System (GEOS) II GCM at a 4° latitude × 5°...

Y. C. Sud; G. K. Walker

1999-09-01T23:59:59.000Z

174

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

175

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

176

MLS and CALIOP cloud ice measurements in the upper troposphere: A constraint from microwave on cloud microphysics  

Science Conference Proceedings (OSTI)

This study examines the consistency and microphysics assumptions among satellite ice water content (IWC) retrievals in the upper troposphere with collocated A-Train radiances from MLS (Microwave Limb Sounder) and lidar backscatters from CALIOP (...

Dong L. Wu; Alyn Lambert; William G. Read; Patrick Eriksson; Jie Gong

177

Aerosol Influence on Cloud Microphysics Examined by Satellite Measurements and Chemical Transport Modeling  

Science Conference Proceedings (OSTI)

Anthropogenic aerosols are hypothesized to decrease cloud drop radius and increase cloud droplet number concentration enhancing cloud optical depth and albedo. Here results have been used from a chemical transport model driven by the output of a ...

Harshvardhan; S. E. Schwartz; C. M. Benkovitz; G. Guo

2002-02-01T23:59:59.000Z

178

Effects of Aerosol Particles on the Microphysics of Coastal Stratiform Clouds  

Science Conference Proceedings (OSTI)

Aerosol particles can act as cloud condensation nuclei and thereby influence the number and size of droplets in clouds. Consequently, anthropogenic particles have the potential to influence global climate by increasing cloud albedo and decreasing ...

Cynthia H. Twohy; Philip A. Durkee; Barry J. Huebert; Robert J. Charlson

1995-04-01T23:59:59.000Z

179

Microphysical Processes Evident in Aerosol Forcing of Tropical Deep Convective Clouds  

Science Conference Proceedings (OSTI)

This study investigates the effects of aerosols on tropical deep convective clouds (DCCs). A series of large-scale, two-dimensional cloud-resolving model simulations was completed, differing only in the concentration of aerosols available to act ...

Rachel L. Storer; Susan C. van den Heever

2013-02-01T23:59:59.000Z

180

Interactions between Cloud Microphysics and Cumulus Convection in a General Circulation Model  

Science Conference Proceedings (OSTI)

In the Colorado State University general circulation model, cumulus detrainment of cloud water and cloud ice has been, up to now, the only direct coupling between convective and large-scale condensation processes. This one-way interaction from ...

Laura D. Fowler; David A. Randall

2002-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Particle Habit Imaging Using Incoherent Light: A First Step toward a Novel Instrument for Cloud Microphysics  

Science Conference Proceedings (OSTI)

The imaging unit of the novel cloud particle instrument Particle Habit Imaging and Polar Scattering (PHIPS) probe has been developed to image individual ice particles produced inside a large cloud chamber. The PHIPS produces images of single ...

Roland Schön; Martin Schnaiter; Zbigniew Ulanowski; Carl Schmitt; Stefan Benz; Ottmar Möhler; Steffen Vogt; Robert Wagner; Ulrich Schurath

2011-04-01T23:59:59.000Z

182

Particle habit imaging using incoherent light: a first step towards a novel instrument for cloud microphysics  

Science Conference Proceedings (OSTI)

The imaging unit of the novel cloud particle instrument PHIPS (Particle Habit Imaging and Polar Scattering probe) has been developed to image individual ice particles produced inside a large cloud chamber. The PHIPS produces images of single ...

Roland Schön; Martin Schnaiter; Zbigniew Ulanowski; Carl Schmitt; Stefan Benz; Ottmar Möhler; Steffen Vogt; Robert Wagner; Ulrich Schurath

183

Cloud Droplet Residual Particle Microphysics in Marine Stratocumulus Clouds Observed during the Monterey Area Ship Track Experiment  

Science Conference Proceedings (OSTI)

The effect of marine boundary layer pollution level (as determined by the aerosol particle number concentration) on the size distribution of aerosol particles that formed cloud droplets in marine stratiform clouds is examined. In situ ...

Elisabeth Öström; Kevin J. Noone; Robert A. Pockalny

2000-08-01T23:59:59.000Z

184

Cirrus Microphysics and Radiative Transfer: Cloud Field Study on 28 October 1986  

Science Conference Proceedings (OSTI)

Cloud data acquired during the cirrus intensive field operation of FIRE 86 are analyzed for a 75 × 50-km2 cirrus cloud field that passed over Wausau, Wisconsin, during the morning of 28 October 1986. Remote-sensing measurements from the ...

Stefan Kinne; Thomas P. Ackerman; Andrew J. Heymsfield; Francisco P. J. Valero; Kenneth Sassen; James D. Spinhirne

1992-05-01T23:59:59.000Z

185

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

E-Print Network (OSTI)

This dissertation focuses on the global investigation of optically thin cirrus cloud optical thickness (tau) and microphysical properties, such as, effective particle size (D_(eff)) and ice crystal habits (shapes), based on the global satellite observations and fast radiative transfer models (RTMs). In the first part, we develop two computationally efficient RTMs simulating satellite observations under cloudy-sky conditions in the visible/shortwave infrared (VIS/SWIR) and thermal inferred (IR) spectral regions, respectively. To mitigate the computational burden associated with absorption, thermal emission and multiple scattering, we generate pre-computed lookup tables (LUTs) using two rigorous models, i.e., the line-by-line radiative transfer model (LBLRTM) and the discrete ordinates radiative transfer model (DISORT). The second part introduces two methods (i.e., VIS/SWIR- and IR-based methods) to retrieve tau and D_(eff) from satellite observations in corresponding spectral regions of the two RTMs. We discuss the advantages and weakness of the two methods by estimating the impacts from different error sources on the retrievals through sensitivity studies. Finally, we develop a new method to infer the scattering phase functions of optically thin cirrus clouds in a water vapor absorption channel (1.38-µm). We estimate the ice crystal habits and surface structures by comparing the inferred scattering phase functions and numerically simulated phase functions calculated using idealized habits.

Wang, Chenxi

2013-08-01T23:59:59.000Z

186

Retrieval of Cloud Microphysical Properties from Thermal Infrared Observations by a Fast Iterative Radiance Fitting Method  

Science Conference Proceedings (OSTI)

An algorithm is presented for inferring the IR optical depth, effective radius, and liquid water path of clouds from multispectral observations of emitted thermal radiation, which takes advantage of the larger number of spectral channels of ...

C. Rathke; J. Fischer

2000-11-01T23:59:59.000Z

187

Propagation of CO2 Laser Radiation Through lce Clouds: Microphysical Effects  

Science Conference Proceedings (OSTI)

Preliminary investigation of the effects of irradiating artificial ice crystals with 10.6 ?m CO2, laser radiation reveals that laser beam-ice crystal interactions can be quite disruptive to ice cloud content under some conditions. The responsible ...

Kenneth Sassen; Mike Griffin

1981-07-01T23:59:59.000Z

188

Retrieval of Cloud Microphysical Parameters from 94-GHz Radar Doppler Power Spectra  

Science Conference Proceedings (OSTI)

A technique is presented that uses Doppler spectra collected from a vertically pointing 94-GHz radar to reconstruct cloud and precipitation drop size distributions. A conceptual model describing the broadening of Doppler spectra by turbulence was ...

David M. Babb; Johannes Verlinde; Bruce A. Albrecht

1999-05-01T23:59:59.000Z

189

Cirrus Microphysical Properties and Air Motion Statistics Using Cloud Radar Doppler Moments. Part II: Climatology  

Science Conference Proceedings (OSTI)

The algorithm described in Part I has been applied to the millimeter cloud radar observations from January 1999 to December 2005 at the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) and Tropical Western Pacific (...

Min Deng; Gerald G. Mace

2008-12-01T23:59:59.000Z

190

The Role of Small Soluble Aerosols in the Microphysics of Deep Maritime Clouds  

Science Conference Proceedings (OSTI)

Some observational evidence—such as bimodal drop size distributions, comparatively high concentrations of supercooled drops at upper levels, high concentrations of small ice crystals in cloud anvils leading to high optical depth, and lightning in ...

A. P. Khain; V. Phillips; N. Benmoshe; A. Pokrovsky

2012-09-01T23:59:59.000Z

191

Simulation of Coastal Circulation in the Eastern Mediterranean Using a Spectral Microphysics Cloud Ensemble Model  

Science Conference Proceedings (OSTI)

The interaction of the cold season land breeze with the background flow in the Eastern Mediterranean and its influence on the climatic distribution of convective precipitation is studied using a 2D nonhydrostatic cloud ensemble model with the ...

Alexander P. Khain; Igor Sednev; V. Khvorostyanov

1996-12-01T23:59:59.000Z

192

Interpretation of Multiwavelength-Retrieved Droplet Effective Radii for Warm Water Clouds in Terms of In-Cloud Vertical Inhomogeneity by Using a Spectral Bin Microphysics Cloud Model  

Science Conference Proceedings (OSTI)

This study examines the impact of in-cloud vertical inhomogeneity on cloud droplet effective radii (CDERs) of water-phase cloud retrieved from 1.6-, 2.1-, and 3.7-?m-band measurements (denoted by r1.6, r2.1, and r3.7, respectively). Discrepancies ...

Takashi M. Nagao; Kentaroh Suzuki; Takashi Y. Nakajima

2013-08-01T23:59:59.000Z

193

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

SciTech Connect

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

Mitchell, David L.

2005-08-08T23:59:59.000Z

194

Contrail Microphysics  

Science Conference Proceedings (OSTI)

This article reviews the current state of understanding of the science of contrails: 1) how they are formed, 2) their microphysical properties as they evolve into contrail cirrus and whether their microphysical properties can be distinguished ...

Andrew Heymsfield; Darrel Baumgardner; Paul DeMott; Piers Forster; Klaus Gierens; Bernd Kärcher

2010-04-01T23:59:59.000Z

195

Influence of Different Microphysical Schemes on the Prediction of Dissolution of Nonreactive Gases by Cloud Droplets and Raindrops  

Science Conference Proceedings (OSTI)

Three microphysical formulations are closely compared to evaluate their impact upon gas scavenging and wet deposition processes. They range from a classical bulk approach to a fully spectral representation, including an intermediate semispectral ...

N. Huret; N. Chaumerliac; H. Isaka; E. C. Nickerson

1994-09-01T23:59:59.000Z

196

Analytical Solutions to the Collection Growth Equation: Comparison with Approximate Methods and Application to Cloud Microphysics Parameterization Schemes  

Science Conference Proceedings (OSTI)

A closed form solution for the collection growth equation as used in bulk microphysical parameterizations is derived. Although the general form is mathematically complex, it can serve as a benchmark for testing a variety of approximations. Two ...

Johannes Verlinde; Piotr J. Flatau; William R. Cotton

1990-12-01T23:59:59.000Z

197

Supplying Local Microphysics Parameterizations with Information about Subgrid Variability: Latin Hypercube Sampling  

Science Conference Proceedings (OSTI)

One problem in computing cloud microphysical processes in coarse-resolution numerical models is that many microphysical processes are nonlinear and small in scale. Consequently, there are inaccuracies if microphysics parameterizations are forced ...

Vincent E. Larson; Jean-Christophe Golaz; Hongli Jiang; William R. Cotton

2005-11-01T23:59:59.000Z

198

Single Aircraft Integration of Remote Sensing and In Situ Sampling for the Study of Cloud Microphysics and Dynamics  

Science Conference Proceedings (OSTI)

Clouds are a critical component of the Earth's coupled water and energy cycles. Poor understanding of cloud–radiation–dynamics feedbacks results in large uncertainties in forecasting human-induced climate changes. Better understanding of cloud ...

Zhien Wang; Jeffrey French; Gabor Vali; Perry Wechsler; Samuel Haimov; Alfred Rodi; Min Deng; Dave Leon; Jeff Snider; Liran Peng; Andrew L. Pazmany

2012-05-01T23:59:59.000Z

199

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...

200

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-

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Analysis of Aircraft, Radiosonde, and Radar Observations in Cirrus Clouds Observed during FIRE II: The Interactions between Environmental Structure, Turbulence, and Cloud Microphysical Properties  

Science Conference Proceedings (OSTI)

Ways to determine the turbulence intensity and the horizontal variability in cirrus clouds have been investigated using First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment II aircraft, radiosonde, and radar data. ...

Samantha A. Smith; Anthony D. DelGenio

2001-03-01T23:59:59.000Z

202

A Model Predicting the Evolution of Ice Particle Size Spectra and Radiative Properties of Cirrus Clouds. Part I: Microphysics  

Science Conference Proceedings (OSTI)

A Lagrangian time-dependent three-dimensional model was developed that predicts the evolution of ice particle size spectra in cirrus clouds in terms of the growth processes of vapor diffusion and aggregation, as well as the cloud updraft profile. ...

David L. Mitchell

1994-03-01T23:59:59.000Z

203

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

204

A Midlatitude Cirrus Cloud Climatology from the Facility for Atmospheric Remote Sensing. Part II: Microphysical Properties Derived from Lidar Depolarization  

Science Conference Proceedings (OSTI)

In Part II of this series of papers describing the results of the extended time observations of cirrus clouds from the University of Utah Facility for Atmospheric Remote Sensing (FARS), the information content of laser backscatter depolarization ...

Kenneth Sassen; Sally Benson

2001-08-01T23:59:59.000Z

205

Cirrus Cloud Microphysical Property Retrieval Using Lidar and Radar Measurements. Part I: Algorithm Description and Comparison with In Situ Data  

Science Conference Proceedings (OSTI)

A retrieval algorithm is described to estimate vertical profiles of cirrus-cloud ice water content (IWC) and general effective size Dge from combined lidar and radar measurements. In the algorithm, the lidar extinction coefficient ? is ...

Zhien Wang; Kenneth Sassen

2002-03-01T23:59:59.000Z

206

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

207

Lightning Frequency and Microphysical Properties of Precipitating Clouds over the Western North Pacific during Winter as Derived from TRMM Multisensor Observations  

Science Conference Proceedings (OSTI)

Tropical Rainfall Measuring Mission observations from multiple sensors including precipitation radar, microwave and infrared radiometers, and a lightning sensor were used to describe precipitation, lightning frequency, and microphysical ...

Yasu-Masa Kodama; Haruna Okabe; Yukie Tomisaka; Katsuya Kotono; Yoshimi Kondo; Hideyuki Kasuya

2007-06-01T23:59:59.000Z

208

Characteristics of CALIPSO and CloudSat Backscatter at the Top Center Layers of Mesoscale Convective Systems and Relation to Cloud Microphysics  

Science Conference Proceedings (OSTI)

Following the discovery of anomalously high values of lidar integrated attenuated backscatter near the top center layers of mesoscale convective systems (MCSs) observed by the NASA Lidar In-Space Technology Experiment (LITE), a search of Cloud ...

C. M. R. Platt; M. A. Vaughan; R. T. Austin

2011-02-01T23:59:59.000Z

209

Cloud Properties Simulated by a Single-Column Model. Part II: Evaluation of Cumulus Detrainment and Ice-Phase Microphysics Using a Cloud-Resolving Model  

Science Conference Proceedings (OSTI)

This paper is the second in a series in which kilometer-scale-resolving observations from the Atmospheric Radiation Measurement Program and output from the University of California, Los Angeles/Colorado State University cloud-resolving model (CRM)...

Yali Luo; Steven K. Krueger; Kuan-Man Xu

2006-11-01T23:59:59.000Z

210

A Climatology of Midlatitude Continental Clouds from the ARM SGP Central Facility: Part I: Low-Level Cloud Macrophysical, Microphysical, and Radiative Properties  

Science Conference Proceedings (OSTI)

A record of single-layer and overcast low cloud (stratus) properties has been generated using approximately 4000 h of data collected from January 1997 to December 2002 at the Atmospheric Radiation Measurement (ARM) Southern Great Plains Central ...

Xiquan Dong; Patrick Minnis; Baike Xi

2005-05-01T23:59:59.000Z

211

Objective Assessment of the Information Content of Visible and Infrared Radiance Measurements for Cloud Microphysical Property Retrievals over the Global Oceans. Part I: Liquid Clouds  

Science Conference Proceedings (OSTI)

The importance of accurately representing the role of clouds in climate change studies has become increasingly apparent in recent years, leading to a substantial increase in the number of satellite sensors and associated algorithms that are ...

Tristan S. L’Ecuyer; Philip Gabriel; Kyle Leesman; Steven J. Cooper; Graeme L. Stephens

2006-01-01T23:59:59.000Z

212

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

213

Explicit Forecasts of Winter Precipitation Using an Improved Bulk Microphysics Scheme. Part I: Description and Sensitivity Analysis  

Science Conference Proceedings (OSTI)

This study evaluates the sensitivity of winter precipitation to numerous aspects of a bulk, mixed-phase microphysical parameterization found in three widely used mesoscale models [the fifth-generation Pennsylvania State University–National Center ...

Gregory Thompson; Roy M. Rasmussen; Kevin Manning

2004-02-01T23:59:59.000Z

214

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

215

Speeding Up the Computation of WRF Double Moment 6-Class Microphysics Scheme with GPU  

Science Conference Proceedings (OSTI)

Weather Research and Forecasting (WRF) Double Moment 6-class (WDM6) microphysics scheme implements a double moment bulk microphysical parameterization of clouds and precipitation and is applicable in mesoscale and general circulation models. WDM6 ...

J. Mielikainen; B. Huang; H.-L. A. Huang; M. D. Goldberg; A. Mehta

216

ARM - PI Product - In-Situ Microphysics from the MPACE IOP  

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

Description Best estimates of the size distributions of supercooled water droplets and ice crystals for mixed-phase clouds measured during M-PACE for spiral ascentsdescents...

217

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

218

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

219

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.

220

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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.


221

ARM - PI Product - Combined Retrieval, Microphysical Retrievals & Heating  

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

ProductsCombined Retrieval, Microphysical Retrievals & ProductsCombined Retrieval, Microphysical Retrievals & Heating Rates Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Combined Retrieval, Microphysical Retrievals & Heating Rates 2011.10.11 - 2012.02.07 Site(s) GAN General Description Microphysical retrievals and heating rates from the AMIE/Gan deployment using the PNNL Combined Retrieval. The PNNL Combined Remote Sensor retrieval algorithm (CombRet) is designed to retrieve cloud and precipitation properties for all sky conditions. The retrieval is based on a combination of several previously published retrievals, with new additions related to the retrieval of cloud microphysical properties when only one instrument is able to detect cloud (i.e. radar only or lidar only).

222

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

223

Microphysical Observations of Tropical Clouds  

Science Conference Proceedings (OSTI)

The results from airborne in situ sampling of convective tropical storms in the Amazon and Kwajalein are presented. Three cases from the Amazon and two from Kwajalein are compared and provide examples of the much larger dataset that was obtained ...

Jeffrey L. Stith; James E. Dye; Aaron Bansemer; Andrew J. Heymsfield; Cedric A. Grainger; Walter A. Petersen; Robert Cifelli

2002-02-01T23:59:59.000Z

224

Sensitivity of Tropical Cyclone Rainbands to Ice-Phase Microphysics  

Science Conference Proceedings (OSTI)

A high-resolution tropical cyclone model with explicit cloud microphysics has been used to investigate the dynamics and energetics of tropical cyclone rainbands. As a first step, the model rainbands have been qualitatively compared with observed ...

Charmaine N. Franklin; Greg J. Holland; Peter T. May

2005-08-01T23:59:59.000Z

225

A Bulk Microphysics Parameterization with Multiple Ice Precipitation Categories  

Science Conference Proceedings (OSTI)

A single-moment bulk microphysics scheme with multiple ice precipitation categories is described. It has 2 liquid hydrometeor categories (cloud droplets and rain) and 10 ice categories that are characterized by habit, size, and density—two ice ...

Jerry M. Straka; Edward R. Mansell

2005-04-01T23:59:59.000Z

226

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

227

Effects of Aerosol Solubility and Regeneration on Warm-Phase Orographic Clouds and Precipitation Simulated by a Detailed Bin Microphysical Scheme  

Science Conference Proceedings (OSTI)

This study evaluates the possible impact of aerosol solubility and regeneration on warm-phase orographic clouds and precipitation. The sensitivity evaluation is performed by simulating cloud formation over two identical 2D idealized mountains ...

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

2010-10-01T23:59:59.000Z

228

Liquid and Ice Cloud Microphysics in the CSU General Circulation Model. Part II: Impact on Cloudiness, the Earth's Radiation Budget, and the General Circulation of the Atmosphere  

Science Conference Proceedings (OSTI)

A prognostic equation for the mass of condensate associated with large-scale cloudiness introduces a direct coupling between the atmospheric moisture budget and the radiation budget through interactive cloud amounts and cloud optical properties. ...

Laura D. Fowler; David A. Randall

1996-03-01T23:59:59.000Z

229

Cirrus Cloud Radiative and Microphysical Properties from Ground Observations and In Situ Measurements during FIRE 1991 and Their Application to Exhibit Problems in Cirrus Solar Radiative Transfer Modeling  

Science Conference Proceedings (OSTI)

Measurements from the FIRE 1991 cirrus cloud field experiment in the central United States are presented and analyzed.

S. Kinne; T. P. Ackerman; M. Shiobara; A. Uchiyama; A. J. Heymsfield; L. Miloshevich; J. Wendell; E. Eloranta; C. Purgold; R. W. Bergstrom

1997-09-01T23:59:59.000Z

230

Impacts of A Priori Databases Using Six WRF Microphysics Schemes on Passive Microwave Rainfall Retrievals  

Science Conference Proceedings (OSTI)

Physically-based rainfall retrievals from passive microwave sensors often make use of cloud resolving models (CRMs) to build a-priori databases of potential rain structures. Each CRM, however, has its own cloud microphysics assumptions. Hence, ...

Ju-Hye Kim; Dong-Bin Shin; Christian Kummerow

231

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:...

232

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

233

Understanding the Importance of Microphysics and Macrophysics for Warm Rain in Marine Low Clouds. Part II: Heuristic Models of Rain Formation  

Science Conference Proceedings (OSTI)

Two simple heuristic model formulations for warm rain formation are introduced and their behavior explored. The first, which is primarily aimed at representing warm rain formation in shallow convective clouds, is a continuous collection model ...

Robert Wood; Terence L. Kubar; Dennis L. Hartmann

2009-10-01T23:59:59.000Z

234

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

235

Organization and Structure of Clouds and Precipitation on the Mid-Atlantic Coast of the United States. Part IV: Retrieval of the Thermodynamic and Cloud Microphysical Structures of a Frontal Rainband from Doppler Radar Data  

Science Conference Proceedings (OSTI)

The thermodynamic and cloud structure of a relatively weak wintertime frontal rainband are derived from dual-Doppler radar measurements, soundings and high resolution surface observations, and with a cloud model. These derivations are simplified ...

Bart Geerts; Peter V. Hobbs

1991-05-01T23:59:59.000Z

236

Aerosol–Cloud Interactions in a Mesoscale Model. Part II: Sensitivity to Aqueous-Phase Chemistry  

Science Conference Proceedings (OSTI)

The feedbacks between aerosols, cloud microphysics, and cloud chemistry are investigated in a mesoscale model. A simple bulk aqueous-phase sulfur chemistry scheme was fully coupled to the existing aerosol and microphysics schemes. The ...

Irena T. Ivanova; Henry G. Leighton

2008-02-01T23:59:59.000Z

237

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

238

Response of ice and liquid water paths of tropical cyclones to global warming simulated by a global nonhydrostatic model with explicit cloud microphysics  

Science Conference Proceedings (OSTI)

Cloud feedback plays a key role in the future climate projection. Using global non-hydrostatic model (GNHM) simulation data for a present-day (CTL) and a warmer (GW) experiment, we estimate the contribution of tropical cyclones (TC) to ice/liquid ...

Yohei Yamada; Masaki Satoh

239

Microphysical Effects of Wintertime Cloud Seeding with Silver Iodide over the Rocky Mountains. Part III: Observations over the Grand Mesa, Colorado  

Science Conference Proceedings (OSTI)

During March 1986, several airborne and ground-based silver iodide (AgI) seeding experiments were conducted over the Grand Mesa, Colorado, during a three-day period of northerly flow and shallow orographic cloud. While little natural snowfall was ...

Arlin B. Super; Bruce A. Boe

1988-10-01T23:59:59.000Z

240

Indirect Impact of Atmospheric Aerosols in Idealized Simulations of Convective–Radiative Quasi Equilibrium. Part II: Double-Moment Microphysics  

Science Conference Proceedings (OSTI)

This paper extends the previous cloud-resolving modeling study concerning the impact of cloud microphysics on convective–radiative quasi equilibrium (CRQE) over a surface with fixed characteristics and prescribed solar input, both mimicking the ...

Wojciech W. Grabowski; Hugh Morrison

2011-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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,...

242

Exploration of the MODIS Cloud-Top Property Products for the Investigation of Equatorial Wave Systems  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectroradiometer (MODIS) observations provide an unprecedented opportunity for studying cloud macrophysical (cloud-top pressure, temperature, height, and phase), microphysical (effective particle size), and ...

Yue Li; Gerald R. North; Ping Yang; Bryan A. Baum

2010-09-01T23:59:59.000Z

243

The influence of Microphysics in the Formation of Intense Wake Lows: A Numerical Modeling Study  

Science Conference Proceedings (OSTI)

A two-dimensional cloud model is used to investigate whether microphysical processes alone within the stratiform rain regions of mesoscale convection systems can induce strong descent and intense surface wake lows accompanying such systems. ...

William A. Gallus Jr.

1996-10-01T23:59:59.000Z

244

A Multimoment Bulk Microphysics Parameterization. Part III: Control Simulation of a Hailstorm  

Science Conference Proceedings (OSTI)

With continuous increase in the resolution of operational numerical weather prediction models, grid-scale saturation schemes that model cloud microphysics are becoming increasingly important. In Parts I and II of this study, the importance of the ...

J. A. Milbrandt; M. K. Yau

2006-12-01T23:59:59.000Z

245

Improved Radiative Transfer Calculations from Information Provided by Bulk Microphysical Schemes  

Science Conference Proceedings (OSTI)

Bulk microphysical schemes are providing increasingly detailed information of hydrometeor profiles both within and below clouds. This information can be used to improve radiative transfer calculations with little increase in computation time. In ...

J. C. Petch

1998-05-01T23:59:59.000Z

246

Aerosol Effects on Simulated Storm Electrification and Precipitation in a Two-Moment Bulk Microphysics Model  

Science Conference Proceedings (OSTI)

The effects of cloud condensation nuclei (CCN) concentrations are found to strongly affect the microphysical and electrical evolution of a numerically simulated small multicell storm. The simulations reproduce the well-known effects of updraft ...

Edward R. Mansell; Conrad L. Ziegler

2013-07-01T23:59:59.000Z

247

High-Cloud Horizontal Inhomogeneity and Solar Albedo Bias  

Science Conference Proceedings (OSTI)

High ice cloud horizontal inhomogeneity is examined using optical depth retrievals from four midlatitude datasets. Three datasets include ice cloud microphysical profiles derived from millimeter cloud radar at the Southern Great Plains ...

Betty Carlin; Qiang Fu; Ulrike Lohmann; Gerald G. Mace; Kenneth Sassen; Jennifer M. Comstock

2002-09-01T23:59:59.000Z

248

On the Relationship between Sulfate and Cloud Droplet Number Concentrations  

Science Conference Proceedings (OSTI)

Comparisons are drawn between the aerosol cloud microphysical theory implicit in the modeling of Kaufman et al. and the cloud droplet and cloud water sulfate concentrations of Leaitch et al. for the purpose of helping to understand the effect of ...

W. R. Leaitch; G. A. Isaac

1994-01-01T23:59:59.000Z

249

Analyzing signatures of aerosol-cloud interactions from satellite retrievals and the GISS GCM to constrain the aerosol indirect effect  

E-Print Network (OSTI)

dust, and pollution aerosol on shallow cloud developmentclouds on indirect aerosol climate forcing, Nature, 432,1014– Albrecht, B. A. , Aerosols, cloud microphysics, and

2008-01-01T23:59:59.000Z

250

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

251

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

252

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

253

The Retrieval of Ice-Cloud Properties from Cloud Radar and Lidar Synergy  

Science Conference Proceedings (OSTI)

Clouds are an important component of the earth’s climate system. A better description of their microphysical properties is needed to improve radiative transfer calculations. In the framework of the Earth, Clouds, Aerosols, and Radiation Explorer (...

Claire Tinel; Jacques Testud; Jacques Pelon; Robin J. Hogan; Alain Protat; Julien Delanoė; Dominique Bouniol

2005-06-01T23:59:59.000Z

254

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

255

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...

256

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

257

Experimental Investigations of Ice in Supercooled Clouds. Part 1: System Description and Growth of Ice by Vapor Deposition  

Science Conference Proceedings (OSTI)

A continuous flow cloud chamber system was constructed for studies of microphysical and chemical processes in supercooled clouds. An important feature of the cloud chamber was the generation of the components of the supercooled clouds external to ...

Naihui Song; Dennis Lamb

1994-01-01T23:59:59.000Z

258

The Impact of Ice Phase Cloud Parameterizations on Tropical Cyclone Prediction  

Science Conference Proceedings (OSTI)

The impact of ice phase cloud microphysical processes on prediction of tropical cyclone environment is examined for two microphysical parameterizations using the Coupled Ocean / Atmosphere Mesoscale Prediction System –Tropical Cyclone model. An ...

Yi Jin; Shouping Wang; Jason Nachamkin; James D. Doyle; Gregory Thompson; Louis Grasso; Teddy Holt; Jon Moskaitis; Hao Jin; Richard M. Hodur; Qingyun Zhao; Ming Liu; Mark DeMaria

259

A Radiation Fog Model with a Detailed Treatment of the Interaction between Radiative Transfer and Fog Microphysics  

Science Conference Proceedings (OSTI)

A one-dimensional radiation fog model is presented which includes a detailed description of the interaction between atmospheric radiative transfer and the microphysical structure of the fog. Aerosol particles and activated cloud droplets are ...

A. Bott; U. Sievers; W. Zdunkowski

1990-09-01T23:59:59.000Z

260

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...

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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.

262

Turbulence, Condensation, and Liquid Water Transport in Numerically Simulated Nonprecipitating Stratocumulus Clouds  

Science Conference Proceedings (OSTI)

Condensation and turbulent liquid water transport in stratocumulus clouds involve complicated interactions between turbulence dynamics and cloud microphysical processes, and play essential roles in defining the cloud structure. This work aims at ...

Shouping Wang; Qing Wang; Graham Feingold

2003-01-01T23:59:59.000Z

263

CCN and Vertical Velocity Influences on Droplet Concentrations and Supersaturations in Clean and Polluted Stratus Clouds  

Science Conference Proceedings (OSTI)

Cloud microphysics and CCN measurements from two marine stratus cloud projects are presented and analyzed. Results show that the increase of cloud droplet concentrations (Nc) withCCN concentrations (NCCN) rolls off for NCCN at 1% supersaturation (...

James G. Hudson; Stephen Noble

264

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to  

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

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Policy Applications Speaker(s): Susanne Bauer Date: December 6, 2011 - 4:00pm Location: 90-4133 Seminar Host/Point of Contact: Surabi Menon The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, However, understanding the net effect of multi-source emitting sectors and the involved cloud feedbacks is

265

Physically Retrieving Cloud and Thermodynamic Parameters from Ultraspectral IR Measurements  

Science Conference Proceedings (OSTI)

A physical inversion scheme has been developed dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A ...

Daniel K. Zhou; William L. Smith Sr.; Xu Liu; Allen M. Larar; Stephen A. Mango; Hung-Lung Huang

2007-03-01T23:59:59.000Z

266

Particle Growth and Drop Collection Efficiency of Warm Clouds as Inferred from Joint CloudSat and MODIS Observations  

Science Conference Proceedings (OSTI)

This study describes an approach for combining CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations to investigate the microphysical processes of warm clouds on the global scale. MODIS column optical thickness ...

Kentaroh Suzuki; Takashi Y. Nakajima; Graeme L. Stephens

2010-09-01T23:59:59.000Z

267

An Airborne Profiling Radar Study of the Impact of Glaciogenic Cloud Seeding on Snowfall from Winter Orographic Clouds  

Science Conference Proceedings (OSTI)

Data from an airborne vertically pointing millimeter-wave Doppler radar are used to study the cloud microphysical effect of glaciogenic seeding of cold-season orographic clouds. Fixed flight tracks were flown downstream of ground-based silver ...

Bart Geerts; Qun Miao; Yang Yang; Roy Rasmussen; Daniel Breed

2010-10-01T23:59:59.000Z

268

Hail Formation via Microphysical Recycling  

Science Conference Proceedings (OSTI)

It is suggested that alternation of low-density riming and wet growth processes play a role in hailstone formation. Such alternation of growth processes, which has been called microphysical recycling, is envisioned to operate in the following ...

John C. Pflaum

1980-01-01T23:59:59.000Z

269

A Quest for Effective Hygroscopic Cloud Seeding  

Science Conference Proceedings (OSTI)

It is shown here that hygroscopic seeding requires two orders of magnitude more hygroscopic agent than can be delivered by flare technology for producing raindrop embryos in concentrations to detect by cloud physics aircraft the microphysical ...

Daniel Rosenfeld; Duncan Axisa; William L. Woodley; Ronen Lahav

2010-07-01T23:59:59.000Z

270

Microphysical Contrasts in Atlantic Stratus  

Science Conference Proceedings (OSTI)

Measurements of a mid-Atlantic clean and polluted cloud are presented. The cleaner cloud had lower concentrations of larger droplets with a broader spectrum and more drizzle drops. The first two characteristics are attributed to the lower cloud ...

James G. Hudson; Hongguo Li

1995-08-01T23:59:59.000Z

271

A Model for Particle Microphysics, Turbulent Mixing, and Radiative Transfer in the Stratocumulus-Topped Marine Boundary Layer and Comparisons with Measurements  

Science Conference Proceedings (OSTI)

A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats ...

Andrew S. Ackerman; Peter V. Hobbs; Owen B. Toon

1995-04-01T23:59:59.000Z

272

Impact of aerosol on mixed-phase stratocumulus during MPACE in...  

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

during MPACE in a mesoscale model with two-moment microphysics Morrison, Hugh MMMASP National Center for Atmospheric Research Pinto, James University of Colorado Curry,...

273

Aircraft-Induced Hole Punch and Canal Clouds: Inadvertent Cloud Seeding  

Science Conference Proceedings (OSTI)

The production of holes and channels in altocumulus clouds by two commercial turboprop aircraft is documented for the first time. An unprecedented dataset combining in situ measurements from microphysical probes with remote sensing measurements ...

Andrew J. Heymsfield; Patrick C. Kennedy; Steve Massie; Carl Schmitt; Zhien Wang; Samuel Haimov; Art Rangno

2010-06-01T23:59:59.000Z

274

The Importance of Cloud Top Lifetime in the Description of Natural Cloud Characteristics  

Science Conference Proceedings (OSTI)

The microphysical and dynamical characteristics of 156 natural summer cumulus clouds have been documented for three locations in North America: Yellowknife, Northwest Territories; Thunder Bay, Ontario; and Miles City, Montana. The measurements (...

Robert S. Schemenauer; G. A. Isaac

1984-02-01T23:59:59.000Z

275

Cloud-Layer Overlap Characteristics Derived from Long-Term Cloud Radar Data  

Science Conference Proceedings (OSTI)

Assumptions regarding the vertical overlap characteristics of horizontal cloudy layers have been shown to be important to both the radiation transfer and the cloud microphysics that are predicted in general circulation models. Certain reasonable ...

Gerald G. Mace; Sally Benson-Troth

2002-09-01T23:59:59.000Z

276

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

277

The radiative influence of aerosol effects on liquid-phase cumulus clouds based on sensitivity studies with two climate models  

E-Print Network (OSTI)

A global black carbon aerosol model. J Geophys Res 101:of interactions between aerosols and cloud microphysics overby anthropogenic sulfate aerosol. J Geophys Res 106: 5279-

Menon, Surabi; Rotstayn, Leon

2005-01-01T23:59:59.000Z

278

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

279

Comparison of Bulk and Bin Warm-Rain Microphysics Models Using a Kinematic Framework  

Science Conference Proceedings (OSTI)

This paper discusses the development and testing of a bulk warm-rain microphysics model that is capable of addressing the impact of atmospheric aerosols on ice-free clouds. Similarly to previous two-moment bulk schemes, this model predicts the ...

Hugh Morrison; Wojciech W. Grabowski

2007-08-01T23:59:59.000Z

280

Modeling Supersaturation and Subgrid-Scale Mixing with Two-Moment Bulk Warm Microphysics  

Science Conference Proceedings (OSTI)

This paper describes further developments of a two-moment warm rain bulk microphysics scheme suitable for addressing the indirect impact of atmospheric aerosols on ice-free clouds in large-eddy simulation (LES) models. The emphasis is on the ...

Hugh Morrison; Wojciech W. Grabowski

2008-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

E-Print Network (OSTI)

). In addition, many numerical simulations of individual clouds show that incorporation of ice- phase by the National Science Foundation. tic structure and evolution of convective storms than that without ice-phase of ice-phase microphysics in the generation of mesoscale structure and evolution did not become evident

Zhang, Da-Lin

282

A Method for Adaptive Habit Prediction in Bulk Microphysical Models. Part II: Parcel Model Corroboration  

Science Conference Proceedings (OSTI)

It is common for cloud microphysical models to use a single axis length to characterize ice crystals. These methods use either the diameter of an equivalent sphere or mass–size equations in conjunction with the capacitance model to close the ...

Jerry Y. Harrington; Kara Sulia; Hugh Morrison

2013-02-01T23:59:59.000Z

283

Observational Study of the Entrainment-Mixing Process in Warm Convective Clouds  

Science Conference Proceedings (OSTI)

Thermodynamical and microphysical measurements collected in convective clouds are examined within the frame of the homogeneous/inhomogeneous mixing concept, to determine how entrainment-mixing processes affect cloud droplets, their number ...

Frédéric Burnet; Jean-Louis Brenguier

2007-06-01T23:59:59.000Z

284

Sources of Error in Dual-Wavelength Radar Remote Sensing of Cloud Liquid Water Content  

Science Conference Proceedings (OSTI)

Dual-wavelength ratio (DWR) techniques offer the prospect of producing high-resolution mapping of cloud microphysical properties, including retrievals of cloud liquid water content (LWC) from reflectivity measured by millimeter-wavelength radars. ...

John K. Williams; J. Vivekanandan

2007-08-01T23:59:59.000Z

285

Determination of the Radiative Properties of Stratiform Clouds from a Nadir-Looking 95-GHz Radar  

Science Conference Proceedings (OSTI)

Several space agencies are presently considering missions with active instruments (radar, lidar), which are able to document cloud stratification and cloud microphysical properties on the global scale. The objective of this paper is to develop an ...

A. Guyot; J. Testud; T. P. Ackerman

2000-01-01T23:59:59.000Z

286

Homogeneous Ice Nucleation and Supercooled Liquid Water in Orographic Wave Clouds  

Science Conference Proceedings (OSTI)

This study investigates ice nucleation mechanisms in cold lenticular wave clouds, a cloud type characterized by quasi-steady-state air motions and microphysical properties. It is concluded that homogeneous ice nucleation is responsible for the ...

Andrew J. Heymsfield; Larry M. Miloshevich

1993-08-01T23:59:59.000Z

287

Aerosol Effects of the Condensation Process on a Convective Cloud Simulation  

Science Conference Proceedings (OSTI)

Using a nonhydrostatic model with a double-moment bulk cloud microphysics scheme, we introduce an aerosol effect on a convective cloud system by accelerating the condensation and evaporation processes (the aerosol condensational effect). To ...

Tatsuya Seiki; Teruyuki Nakajima

288

Parameterization and Impact of Ice initiation Processes Relevant to Numerical Model Simulations of Cirrus Clouds  

Science Conference Proceedings (OSTI)

An effort to improve descriptions of ice initiation processes of relevance to cirrus clouds for use in regional-scale numerical cloud models with bulk microphysical schemes is described. This is approached by deriving practical parameterizations ...

Paul J. DeMott; Michael P. Meyers; William R. Cotton

1994-01-01T23:59:59.000Z

289

Factors Determining the Impact of Aerosols on Surface Precipitation from Clouds: An Attempt at Classification  

Science Conference Proceedings (OSTI)

The simulation of the dynamics and the microphysics of clouds observed during the Large-Scale Biosphere–Atmosphere Experiment in Amazonia—Smoke, Aerosols, Clouds, Rainfall, and Climate (LBA–SMOCC) campaign, as well as extremely continental and ...

A. P. Khain; N. BenMoshe; A. Pokrovsky

2008-06-01T23:59:59.000Z

290

Size Distributions and Dynamical Properties of Shallow Cumulus Clouds from Aircraft Observations and Satellite Data  

Science Conference Proceedings (OSTI)

In this paper aircraft observations of shallow cumulus over Florida during the Small Cumulus Microphysics Study (SCMS) are analyzed. Size distributions of cloud fraction, mass flux, and in-cloud buoyancy flux are derived. These distributions ...

Stefaan M. A. Rodts; Peter G. Duynkerke; Harm J. J. Jonker

2003-08-01T23:59:59.000Z

291

Evaluation of MM5 Optically Thin Clouds over Europe in Fall Using ICESat Lidar Spaceborne Observations  

Science Conference Proceedings (OSTI)

The description of clouds in mesoscale models has progressed significantly during recent years by improving microphysical schemes with more physical parameterizations deduced from observations. Recently, the first lidar in space, the Ice, Cloud, ...

H. Chepfer; M. Chiriaco; R. Vautard; J. Spinhirne

2007-07-01T23:59:59.000Z

292

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

293

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

294

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.

295

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

296

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

297

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.

298

[10-461] Quantifying the Uncertainties of Aerosol Indirect Effects and Impacts on Decadal-Scale Climate Variability in NCAR CAM5 and CESM1  

E-Print Network (OSTI)

) unified parameterization for ice nucleation that includes homogeneous nucleation (in cold cirrus) and heterogeneous nucleation on ice nuclei (IN) with different mechanisms in mixed-phase and cold cirrus clouds (vertical velocity) which drives aerosol activation, cloud microphysics parameterizations, cloud

299

Relating Cirrus Cloud Properties to Observed Fluxes: A Critical Assessment  

Science Conference Proceedings (OSTI)

The accuracy needed in cirrus cloud scattering and microphysical properties is quantified such that the radiative effect on climate can he determined. Our ability to compute and observe these properties to within needed accuracies is assessed, ...

A. M. Vogelmann; T. P. Ackerman

1995-12-01T23:59:59.000Z

300

Small-Scale Variability in Warm Continental Cumulus Clouds  

Science Conference Proceedings (OSTI)

We have analyzed small-scale fluctuations in microphysical, dynamical and thermodynamical parameters measured in two warm cumulus clouds during the Cooperative Convective Precipitation Experiment (CCOPE) project (1981) in light of predictions of ...

P. H. Austin; M. B. Baker; A. M. Blyth; J. B. Jensen

1985-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Airborne Cloud-Physics Projects From 1974 Through 1984  

Science Conference Proceedings (OSTI)

Most of the principal airborne cloud-physics projects during the ten-year period 1974-1984 are documented to provide selected information on the type and quantity of microphysical data that have beencollected. The emphasis is on measurements ...

Richard K. Jeck

1986-12-01T23:59:59.000Z

302

95-GHz Polarimetric Radar Measurements of Orographic Cap Clouds  

Science Conference Proceedings (OSTI)

The use of millimeter-wavelength radars for cloud microphysical research was investigated in experiments at the Elk Mountain Observatory near Laramie, Wyoming, between April 1990 and March 1992. The 95-GHz polarimetric radar used in these ...

Andrew Pazmany; James Mead; Robert McIntosh; Mark Hervig; Robert Kelly; Gabor Vali

1994-02-01T23:59:59.000Z

303

Parameterization of Bulk Condensation in Numerical Cloud Models  

Science Conference Proceedings (OSTI)

The accuracy of the moist saturation adjustment scheme has been evaluated using a three-dimensional explicit microphysical cloud model. It was found that the error in saturation adjustment depends strongly on the CCN concentration in the ambient ...

Yefim L. Kogan; William J. Martin

1994-06-01T23:59:59.000Z

304

On the Transition of Contrails into Cirrus Clouds  

Science Conference Proceedings (OSTI)

In situ observations of the microphysical properties of upper-tropospheric contrails and cirrus clouds have been performed during more than 15 airborne missions over central Europe. Experimental and technical aspects concerning in situ ...

F. Schröder; B. Kärcher; C. Duroure; J. Ström; A. Petzold; J.-F. Gayet; B. Strauss; P. Wendling; S. Borrmann

2000-02-01T23:59:59.000Z

305

Chaff Seeding Effects in a Dynamical-Electrical Cloud Model  

Science Conference Proceedings (OSTI)

A two-dimensional, slab-symmetric, time-dependent cloud model has been devised to simulate deep convection in the atmosphere. The dynamics and thermodynamics of deep convection are prescribed and the microphysics of the liquid phase is ...

John H. Helsdon Jr.

1980-09-01T23:59:59.000Z

306

Relative Humidity and Temperature Influences on Cirrus Formation and Evolution: Observations from Wave Clouds and FIRE II  

Science Conference Proceedings (OSTI)

Measurements in orographic wave clouds. and in cirrus sampled during FIRE II, are used to investigate ice nucleation in the upper troposphere. The dynamically and microphysically simpler quasi-steady-state wave clouds provide relatively ideal ...

Andrew J. Heymsfield; Larry M. Miloshevich

1995-12-01T23:59:59.000Z

307

The Effects of Evaporation, Water Load and Wind Shear on Cloud Development in a Three-Dimensional Numerical Model  

Science Conference Proceedings (OSTI)

Steiner's (1973) three-dimensional cloud model has been updated to incorporate the deep anelastic system of equations and the microphysical parameterization scheme of Kessler (1969) for precipitation growth. The interactions between cloud ...

Man Kong Yau

1980-02-01T23:59:59.000Z

308

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

309

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

310

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

311

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

312

Cumulus Microphysics and Climate Sensitivity  

Science Conference Proceedings (OSTI)

Precipitation processes in convective storms are potentially a major regulator of cloud feedback. An unresolved issue is how the partitioning of convective condensate between precipitation-size particles that fall out of updrafts and smaller ...

Anthony D. Del Genio; William Kovari; Mao-Sung Yao; Jeffrey Jonas

2005-07-01T23:59:59.000Z

313

Effects of Radiation and Turbulence on the Diabatic Heating and Water Budget of the Stratiform Region of a Tropical Cloud Cluster  

Science Conference Proceedings (OSTI)

A two-dimensional, kinematic model, incorporating ice- and water-cloud microphysics, visible and infrared radiation, and convective adjustment, is used to diagnose the thermodynamic, water vapor, and hydrometeor fields of the stratiform clouds ...

Dean D. Churchill; Robert A. Houze Jr.

1991-04-01T23:59:59.000Z

314

Implementation of a Silver Iodide Cloud-Seeding Parameterization in WRF. Part I: Model Description and Idealized 2D Sensitivity Tests  

Science Conference Proceedings (OSTI)

A silver iodide (AgI) cloud-seeding parameterization has been implemented into the Thompson microphysics scheme of the Weather Research and Forecasting model to investigate glaciogenic cloud-seeding effects. The sensitivity of the parameterization ...

Lulin Xue; Akihiro Hashimoto; Masataka Murakami; Roy Rasmussen; Sarah A. Tessendorf; Daniel Breed; Shaun Parkinson; Pat Holbrook; Derek Blestrud

2013-06-01T23:59:59.000Z

315

Cirrus Cloud Properties and the Large-Scale Meteorological Environment: Relationships Derived from A-Train and NCEP–NCAR Reanalysis Data  

Science Conference Proceedings (OSTI)

Empirical knowledge of how cirrus cloud properties are coupled with the large-scale meteorological environment is a prerequisite for understanding the role of microphysical processes in the life cycle of cirrus cloud systems. Using active and ...

Elizabeth Berry; Gerald G. Mace

2013-05-01T23:59:59.000Z

316

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

317

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

318

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

319

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

320

Numerical Simulation of Cloud–Clear Air Interfacial Mixing: Homogeneous versus Inhomogeneous Mixing  

Science Conference Proceedings (OSTI)

This note presents an analysis of several dozens of direct numerical simulations of the cloud–clear air mixing in a setup of decaying moist turbulence with bin microphysics. The goal is to assess the instantaneous relationship between the ...

Miroslaw Andrejczuk; Wojciech W. Grabowski; Szymon P. Malinowski; Piotr K. Smolarkiewicz

2009-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Multiparameter Radar and Aircraft Study of Raindrop Spectral Evolution in Warm-based Clouds  

Science Conference Proceedings (OSTI)

Radar measurements of reflectivity differential reflectivity, and X-band (3-cm wavelength) specific attenuation are used to inter some microphysical characteristics of warm-based convective clouds with emphasis on raindrop spectral evolution. The ...

V. N. Bringi; D. A. Burrows; S. M. Menon

1991-06-01T23:59:59.000Z

322

Microwave Simulations of a Tropical Rainfall System with a Three-Dimensional Cloud Model  

Science Conference Proceedings (OSTI)

A three-dimensional cloud model-microwave radiative transfer model combination is used to study the relations among the precipitation and other microphysical characteristics of a tropical oceanic squall line and the upwelling radiance at ...

Robert F. Adler; Hwa-Young M. Yeh; N. Prasad; Wei-Kuo Tao; Joanne Simpson

1991-07-01T23:59:59.000Z

323

The Influence of Entrainment and Mixing Assumption on Aerosol–Cloud Interactions in Marine Stratocumulus  

Science Conference Proceedings (OSTI)

This study uses large-eddy simulation with bin microphysics to investigate the influence of entrainment and mixing on aerosol–cloud interactions in the context of idealized, nocturnal, nondrizzling marine stratocumulus (Sc). Of particular ...

Adrian A. Hill; Graham Feingold; Hongli Jiang

2009-05-01T23:59:59.000Z

324

A Clustering Approach to Compare Cloud Model Simulations to Satellite Observations  

Science Conference Proceedings (OSTI)

Cloud-resolving models (CRMs) offer an important pathway to interpret satellite observations of microphysical properties of storms. High-frequency microwave brightness temperatures (Tbs) respond to precipitating-sized ice particles and can ...

Fang Wang; Christian Kummerow

2012-11-01T23:59:59.000Z

325

Separating Cloud and Drizzle Radar Moments during Precipitation Onset Using Doppler Spectra  

Science Conference Proceedings (OSTI)

The retrieval of cloud, drizzle, and turbulence parameters using radar Doppler spectra is challenged by the convolution of microphysical and dynamical influences and the overall uncertainty introduced by turbulence. A new technique that utilizes ...

Edward P. Luke; Pavlos Kollias

2013-08-01T23:59:59.000Z

326

On the Combined Effects of Turbulence and Gravity on Droplet Collisions in Clouds: A Numerical Study  

Science Conference Proceedings (OSTI)

This paper examines the combined influences of turbulence and gravity on droplet collision statistics in turbulent clouds by means of direct numerical simulation (DNS). The essential microphysical mechanisms that determine the geometric collision ...

Eric J. P. Woittiez; Harm J. J. Jonker; Luķs M. Portela

2009-07-01T23:59:59.000Z

327

Investigation of Regional and Seasonal Variations in Marine Boundary Layer Cloud Properties from MODIS Observations  

Science Conference Proceedings (OSTI)

To aid in understanding the role that marine boundary layer (MBL) clouds play in climate and assist in improving their representations in general circulation models (GCMs), their long-term microphysical and macroscale characteristics are ...

Michael P. Jensen; Andrew M. Vogelmann; William D. Collins; Guang J. Zhang; Edward P. Luke

2008-10-01T23:59:59.000Z

328

Environmental Control of Cloud-to-Ground Lightning Polarity in Severe Storms  

Science Conference Proceedings (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 ...

Lawrence D. Carey; Kurt M. Buffalo

2007-04-01T23:59:59.000Z

329

A New Parameterization of an Asymmetry Factor of Cirrus Clouds for Climate Models  

Science Conference Proceedings (OSTI)

The aspect ratio (AR) of a nonspherical ice particle is identified as the key microphysical parameter to determine its asymmetry factor for solar radiation. The mean effective AR is defined for cirrus clouds containing various nonspherical ice ...

Qiang Fu

2007-11-01T23:59:59.000Z

330

Airship Measurements of Ship’s Exhaust Plumes and Their Effect on Marine Boundary Layer Clouds  

Science Conference Proceedings (OSTI)

High-resolution aerosol, trace gas, and cloud microphysical measurements were made from an airship during transects across ships exhaust plumes advecting downwind of ships in the marine boundary layer (MBL). This study was part of the Office of ...

G. M. Frick; W. A. Hoppel

2000-08-01T23:59:59.000Z

331

A Case Study of Ships Forming and Not Forming Tracks in Moderately Polluted Clouds  

Science Conference Proceedings (OSTI)

The effects of anthropogenic particulate emissions from ships on the radiative, microphysical, and chemical properties of moderately polluted marine stratiform clouds are examined. A case study of two ships in the same air mass is presented where ...

Kevin J. Noone; Elisabeth Öström; Ronald J. Ferek; Tim Garrett; Peter V. Hobbs; Doug W. Johnson; Jonathan P. Taylor; Lynn M. Russell; Richard C. Flagan; John H. Seinfeld; Colin D. O’Dowd; Michael H. Smith; Philip A. Durkee; Kurt Nielsen; James G. Hudson; Robert A. Pockalny; Lieve De Bock; René E. Van Grieken; Richard F. Gasparovic; Ian Brooks

2000-08-01T23:59:59.000Z

332

A Numerical Simulation of Winter Cumulus Electrification. Part I: Shallow Cloud  

Science Conference Proceedings (OSTI)

The development of electricity in a shallow wintertime cumulus was studied using an axisymmetric cloud model containing both microphysical and electrical charge separation processes during graupel formation. The charge separation mechanisms ...

Tsutomu Takahashi

1983-05-01T23:59:59.000Z

333

A Numerical Study of the Warm Rain Process in Orographic Clouds  

Science Conference Proceedings (OSTI)

A technique for numerical simulation of a stationary, two-dimensional laminar flow process is described. Based on this technique, a model for warm rain microphysics in an orographic cloud was developed. The model includes condensation, ...

Naihui Song; John Marwitz

1989-11-01T23:59:59.000Z

334

Theoretical Formulation of Collision Rate and Collision Efficiency of Hydrodynamically Interacting Cloud Droplets in Turbulent Atmosphere  

Science Conference Proceedings (OSTI)

A methodology for conducting direct numerical simulations (DNSs) of hydrodynamically interacting droplets in the context of cloud microphysics has been developed and used to validate a new kinematic formulation capable of describing the collision ...

Lian-Ping Wang; Orlando Ayala; Scott E. Kasprzak; Wojciech W. Grabowski

2005-07-01T23:59:59.000Z

335

Radiative Properties of Boundary Layer Clouds: Droplet Effective Radius versus Number Concentration  

Science Conference Proceedings (OSTI)

The plane-parallel model for the parameterization of clouds in global climate models is examined in order to estimate the effects of the vertical profile of the microphysical parameters on radiative transfer calculations for extended boundary ...

Jean-Louis Brenguier; Hanna Pawlowska; Lothar Schüller; Rene Preusker; Jürgen Fischer; Yves Fouquart

2000-03-01T23:59:59.000Z

336

Summer Cumulus Cloud Seeding Experiments near Yellowknife and Thunder Bay, Canada  

Science Conference Proceedings (OSTI)

A summer (June and July) cumulus cloud seeding experiment was conducted in Canada near Yellowknife in 1975 and 1976, and Thunder Bay in 1977 and 1978. Microphysical and dynamical measurements were made with three instrumented aircraft, flying in ...

G. A. Isaac; J. W. Strapp; R. S. Schemenauer; J. I. Macpherson

1982-09-01T23:59:59.000Z

337

Effects of Cloud Seeding, Latent Heat of Fusion, and Condensate Loading on Cloud Dynamics and Precipitation Evolution: A Numerical Study  

Science Conference Proceedings (OSTI)

This study attempts to isolate the dynamic and microphysical effects of seeding. A two-dimensional, time-dependent cloud model has been used to simulate silver iodide (AgI) seeding of convective clouds. Two major dynamic effects (latent heat of ...

Harold D. Orville; Jeng-Ming Chen

1982-12-01T23:59:59.000Z

338

The Effects of Very Large Drops on Cloud Absorption. Part I: Parcel Models  

Science Conference Proceedings (OSTI)

In an effort to bring more realism cloud-radiation calculations, arising-parcel model of cloud microphysics and a 191 waveband model of atmospheric radiation (ATRAD) have been brought to bear on the problem of cloud absorption of solar radiation, ...

W. J. Wiscombe; R. M. Welch; W. D. Hall

1984-04-01T23:59:59.000Z

339

Predictions of Saturation Ratio for Cloud Microphysical Models  

Science Conference Proceedings (OSTI)

The saturation development equation is solved analytically to give a solution that is more general than the existing analytical solution. This analytical solution provides accurate predictions of the saturation ratio and allows the use of ...

Jen-Ping Chen

1994-05-01T23:59:59.000Z

340

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

342

A Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site  

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

Composite and Microphysical Study of Composite and Microphysical Study of Jet Stream Cirrus Over the ARM Site J. M. Haynes and G. L. Stephens Department of Atmospheric Science Colorado State University Fort Collins, Colorado Introduction Cirrus are known to play an important role in the radiative budget of the earth-atmosphere system. Previous studies have shown that cirrus within strong jet streams account for about 40% to 60% of all cirrus observed in the continental United States during the winter (Menzel et al. 1992). However, the connection between the properties of mid-latitude cirrus clouds and the large-scale flow that supports them is still, to a large degree, unknown. This study seeks to better quantify and understand this relationship through two interrelated investigations.

343

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

344

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

345

Millimeter wave scattering from ice crystals and their aggregates: Comparing cloud model simulations with X and Kaband  

E-Print Network (OSTI)

of the relative amounts of cloud liquid and ice. Modeling studies have shown that the poorly understood ice phase parameterizations has proven to be a difficult task. This study evaluates results of different ice microphysics conclusions about the appropriateness of different CRM ice microphysics parameterizations. Citation: Botta, G

346

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

347

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

348

Numerical Simulations of the Microphysics and Electrification of the Weakly Electrified 9 February 1993 TOGA COARE Squall Line: Comparisons with Observations  

Science Conference Proceedings (OSTI)

A cloud scale model with a 12-class bulk microphysics scheme, including 10 ice phases and a 3D lightning parameterization, was used to investigate the electrical properties of a well-documented tropical squall line from the Tropical Ocean Global ...

Alexandre O. Fierro; Lance M. Leslie; Edward R. Mansell; Jerry M. Straka

2008-01-01T23:59:59.000Z

349

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

350

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

351

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

352

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

353

Interactions between Topographic Airflow and Cloud/Precipitation Development during the Passage of a Winter Storm in Arizona  

Science Conference Proceedings (OSTI)

A case study showing comparisons between observations and numerical simulations of the passage of a winter storm over complex terrain is presented. The interactions between the mesoscale and cloud environments and the microphysical and dynamical ...

Roelof T. Bruintjes; Terry L. Clark; William D. Hall

1994-01-01T23:59:59.000Z

354

Information Content of AVHRR Channels 4 and 5 with Respect to the Effective Radius of Cirrus Cloud Particles  

Science Conference Proceedings (OSTI)

This paper investigates the important difference in the relationship between brightness temperatures between the 11-?m and the 12-?n AVHRR data and the microphysical properties of the semitransparent cirrus clouds. In the nonscattering ...

F. Parol; J. C. Buriez; G. Brogniez; Y. Fouquart

1991-07-01T23:59:59.000Z

355

An Artificial Neural Network model to reduce false alarms in satellite precipitation products using MODIS and CloudSat observations  

Science Conference Proceedings (OSTI)

The Moderate Resolution Imaging Spectro-radiometer (MODIS) instrument aboard the NASA Earth Observing System (EOS) Aqua and Terra platform with 36 spectral bands provides valuable information about cloud microphysical characteristics and therefore ...

Nasrin Nasrollahi; Kuolin Hsu; Soroosh Sorooshian

356

Airship Measurements of Aerosol Size Distributions, Cloud Droplet Spectra, and Trace Gas Concentrations in the Marine Boundary Layer  

Science Conference Proceedings (OSTI)

The use of an airship as a platform to conduct atmospheric chemistry, aerosol, and cloud microphysical research is described, and results from demonstration flights made off the Oregon coast are presented. The slow speed of the airship makes it ...

G. M. Frick; W. A. Hoppel

1993-11-01T23:59:59.000Z

357

The Influence of Time-Dependent Melting on the Dynamics and Precipitation Production in Maritime and Continental Storm Clouds  

Science Conference Proceedings (OSTI)

Simulations of one maritime and four continental observed cases of deep convection are performed with the Hebrew University Cloud Model that has spectral bin microphysics. The maritime case is from observations made on 18 September 1974 during ...

Vaughan T. J. Phillips; Andrei Pokrovsky; Alexander Khain

2007-02-01T23:59:59.000Z

358

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

Science Conference Proceedings (OSTI)

A regional climate model is used to simulate boundary layer stratocumulus (Sc) clouds over the southeast Pacific off South America during August–October 1999 and to study their dynamical, radiative, and microphysical properties and their ...

Yuqing Wang; Shang-Ping Xie; Haiming Xu; Bin Wang

2004-01-01T23:59:59.000Z

359

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

360

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

362

ARM - Measurement - Cloud particle size distribution  

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

size distribution size distribution 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 particle size distribution The number of cloud particles present in any given volume of air within a specified size range, including liquid and ice. 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 WSACR : Scanning ARM Cloud Radar, tuned to W-Band (95GHz) Field Campaign Instruments CPI : Cloud Particle Imager CLDAEROSMICRO : Cloud and Aerosol Microphysical Properties

363

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.

364

ARM - Facility News Article  

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

focused on obtaining microphysical data on clouds consisting of both water droplets and ice crystals (i.e., mixed phase). Throughout much of the study period, radiosonde data was...

365

ARM - 2008 ARM Science Team Meeting  

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

and Tropical Cirrus 9:00 am - 9:20 am Xiaohong Liu: Evaluation of a New Mixed-phase Cloud Microphysics Parameterization with Single Column Model, CAPT Forecasts, and...

366

Atmos. Chem. Phys., 12, 40454063, 2012 www.atmos-chem-phys.net/12/4045/2012/  

E-Print Network (OSTI)

and modified the glaciation of mixed phase clouds. Our simulations show that during the dust events, ice crys treats particle microphysics and chemical composition. Sophisticated parameterizations for aerosol ac- tivation and ice nucleation, together with two-moment cloud microphysics are used to calculate

Meskhidze, Nicholas

367

Comparison between Standard and Modified Forward Scattering Spectrometer Probes during the Small Cumulus Microphysics Study  

Science Conference Proceedings (OSTI)

Microphysical measurements performed during the Small Cumulus Microphysics Study (SCMS) experiment are analyzed in order to examine the instrumental limitations of forward scattering spectrometer probes (FSSPs). Complementary information ...

Frédéric Burnet; Jean-Louis Brenguier

2002-10-01T23:59:59.000Z

368

Relations of kinematics, microphysics and electrification in an isolated mountain thunderstorm  

SciTech Connect

This paper addresses aspects of the airflow, microphysics, and electrification in a mountain thunderstorm which occurred on 7 August 1979 over the Langmuir Laboratory near Socorro, New Mexico, site of the Thunderst Research International Program (TRIP). Single Doppler observations are used to form a conceptual model of the essentially one-dimensional storm nematic numerical cloud model is employed with the analytic updraft profile to diagnose the evolution of temperature, water substance, radar reflectivity, space charge density and axial electric field in the main updraft region. Retrieved thermal, microphysical, and electrical variabiles are verified with in situ aircraft and balloon observations and measured radar reflectivity. The calculated ing graupel particles is in a direct proportion to cloud and precipitation content, and attains a peak value of about 10 C km/sup -3/ min/sup -1/ between -30/sup 0/ and -40/sup 0/C. and vertical electric field imply that the noninductive graupel-ice charge separation mechanism accounts for a substantial portion of the storm's total separated charge. The peak noninductive charging rate appears to balance the discharge rate implied by the observed flash rate.

Ziegler, C.L.; Ray, P.S.; MacGorman, D.R.

1986-10-01T23:59:59.000Z

369

Parameterization of Heterogeneous Droplet Chemistry for Use in Bulk Cloud Models  

Science Conference Proceedings (OSTI)

Comparison of in-cloud sulfate production by a bulk-parameterized cloud model, a modified bulk parameterized model, and an explicit microphysical model for a wide variety of scenarios has been used as the basis for deriving a parameterization of ...

Po-Fat Yuen; Dean A. Hegg; Timothy V. Larson; Mary C. Barth

1996-05-01T23:59:59.000Z

370

The 13–14 December 2001 IMPROVE-2 Event. Part II: Comparisons of MM5 Model Simulations of Clouds and Precipitation with Observations  

Science Conference Proceedings (OSTI)

This paper compares airborne in situ observations of cloud microphysical parameters with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) simulations, using the Reisner-2 ...

Matthew F. Garvert; Christopher P. Woods; Brian A. Colle; Clifford F. Mass; Peter V. Hobbs; Mark T. Stoelinga; Justin B. Wolfe

2005-10-01T23:59:59.000Z

371

DISSERTATION THE EFFECTS OF RADIATIVE AND MICROPHYSICAL PROCESSES ON  

E-Print Network (OSTI)

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

Harrington, Jerry Y.

372

ARM - Evaluation Product - CMWG Data - SCM-Forcing Data, Cloud  

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

ProductsCMWG Data - SCM-Forcing Data, Cloud ProductsCMWG Data - SCM-Forcing Data, Cloud Microphysical Properties and Radiative Heating Profiles Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : CMWG Data - SCM-Forcing Data, Cloud Microphysical Properties and Radiative Heating Profiles Site(s) GAN HFE NSA SGP TWP General Description SCM-forcing data are derived from the ARM Program observational data using the constrained variational analysis approach (Zhang and Lin 1997 and Zhang et al. 2001). The resulting products include both the large-scale forcing terms and the evaluation fields, which can be used for driving the Single-Column Models (SCMs) and Cloud Resolving Models (CRMs) and validating model simulations. Results from our studies are then used to

373

Testing Statistical Cloud Scheme Ideas in the GFDL Climate Model  

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

Testing Statistical Cloud Scheme Ideas in the GFDL Climate Model Testing Statistical Cloud Scheme Ideas in the GFDL Climate Model Klein, Stephen Lawrence Livermore National Laboratory Pincus, Robert NOAA-CIRES Climate Diagnostics Center Category: Modeling Statistical cloud schemes (or assumed probability distribution function cloud schemes) are attractive because they provide a way to implement horizontal sub-grid scale cloud heterogeneity in a self-consistent way between physical parameterizations of the a climate model, such as radiation and cloud microphysics. In this work, we will present results dealing with two aspects of our ongoing work towards the implementation of statistical cloud scheme ideas in the climate model of Geophysical Fluid Dynamics Laboratory. First, we will address the representation of cloud

374

Inclusion of Ice Microphysics in the NCAR Community Atmospheric Model Version 3 (CAM3)  

SciTech Connect

A prognostic equation for ice crystal number concentration together with an ice nucleation scheme are implemented in the National Center for Atmospheric Research (NCAR) Community Atmospheric Model Version 3 (CAM3) with the aim of studying the indirect effect of aerosols on cold clouds. The effective radius of ice crystals which is used in the radiation and gravitational settlement calculations is now calculated from model predicted mass and number of ice crystals rather than diagnosed as a function of temperature. We add a water vapor deposition scheme to replace the condensation and evaporation (C-E) in the standard CAM3 for ice clouds. The repartitioning of total water into liquid and ice in mixed-phase clouds as a function of temperature is removed, and ice supersaturation is allowed. The predicted ice water content in the modified CAM3 is in better agreement with the Aura MLS data than that in the standard CAM3. The cirrus cloud fraction near the tropical tropopause, which is underestimated in the standard CAM3, is increased, and the cold temperature bias there is reduced by 1-2 °K. However, an increase in the cloud fraction in polar regions makes the underestimation of downwelling shortwave radiation in the standard CAM3 even worse. A sensitivity test reducing the threshold relative humidity with respective to ice (RHi) for heterogeneous ice nucleation from 120% to 105% (representing nearly perfert ice nuclei) increases the global cloud cover by 1.7%, temperature near the tropical tropopause by 4-5 °K, and water vapor in the stratosphere by 50-90%.

Liu, Xiaohong; Penner, Joyce E.; Ghan, Steven J.; Wang, M.

2007-09-15T23:59:59.000Z

375

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.

376

ARM - Publications: Science Team Meeting Documents  

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

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

377

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

378

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

379

The cloud condensation nuclei and ice nuclei effects on tropical anvil characteristics and water vapor of the tropical tropopause layer  

SciTech Connect

Cloud anvils from deep convective clouds are of great importance to the radiative energy budget and the aerosol impact on them is the least understood. Few studies examined the effects of both cloud condensation nuclei (CCN) and ice nuclei (IN) on anvil properties and water vapor content (WVC) in the Tropical Tropopause Layer (TTL). Using a 3-dimensional cloud-resolving model with size-resolved cloud microphysics, we focus on the CCN and IN effects on cloud anvil properties and WVC in the TTL. We find that cloud microphysical changes induced by CCN/IN play a very important role in determining cloud anvil area and WVC in the TTL, whether convection is enhanced or suppressed. Also, CCN effects on anvil microphysical properties, anvil size and lifetime are much more evident relative to IN. IN has little effect on convection, but can increase ice number and mass concentrations significantly under humid conditions. CCN in the PBL is found to have greater effects on convective strength and mid-tropospheric CCN has negligible effects on convection and cloud properties. Convective transport may only moisten the main convective outflow region but the cloud anvil size determines the WVC in the TTL domain. This study shows an important role of CCN in the lower-troposphere in modifying convection, the upper-level cloud properties. It also shows the effects of IN and the PBL CCN on the upper-level clouds depends on the humidity, resolving some contradictory results in past studies. 2

Fan, Jiwen; Comstock, Jennifer M.; Ovchinnikov, Mikhail

2010-11-10T23:59:59.000Z

380

Simulations of cirrus clouds using an explicit cloud model: integrating ARM  

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

Simulations of cirrus clouds using an explicit cloud model: integrating ARM Simulations of cirrus clouds using an explicit cloud model: integrating ARM water vapor and forcing data for analysis of cirrus formation and evolution Comstock, Jennifer Pacific Northwest National Laboratory Lin, Ruei-Fong NASA/Goddard Space Flight Center Starr, David NASA/Goddard Space Flight Center Yang, Ping Texas A&M Category: Modeling Understanding the atmospheric conditions required to initiate cirrus formation and produce observed microphysical properties is crucial to improving the representation of cirrus clouds in climate models. Ice formation in cirrus generally occurs at cold temperatures (below -30 ļ‚°C) and can take the form of either homogeneous or heterogeneous nucleation. The ice supersaturation required for ice formation is smaller for

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

A Theoretical Study of the Wet Removal of Atmospheric Pollutants. Part V: The Uptake, Redistribution, and Deposition of (NM4)4SO4 by a Convective Cloud Containing Ice  

Science Conference Proceedings (OSTI)

The effects of an ice phase on the wet deposition of aerosol particles was studied by means of the authors’ 2D cloud dynamics model with spectral microphysics applied to the Cooperative Convective Precipitation Experiment in Miles City, Montana, ...

Petra S. Respondek; A. I. Flossmann; R. R. Alheit; H. R. Pruppacher

1995-06-01T23:59:59.000Z

382

A Large-Droplet Mode and Prognostic Number Concentration of Cloud Droplets in the Colorado State University Regional Atmospheric Modeling System (RAMS). Part I: Module Descriptions and Supercell Test Simulations  

Science Conference Proceedings (OSTI)

The microphysics module of the version of the Regional Atmospheric Modeling System (RAMS) maintained at Colorado State University has undergone a series of improvements, including the addition of a large-cloud-droplet mode from 40 to 80 ?m in ...

Stephen M. Saleeby; William R. Cotton

2004-01-01T23:59:59.000Z

383

A Theoretical Study of the Wet Removal of Atmospheric Pollutants. Part IV: The Uptake and Redistribution of Aerosol Particles through Nucleation and Impaction Scavenging by Growing Cloud Drops and Ice Particles  

Science Conference Proceedings (OSTI)

A theoretical model has been formulated which allows the study of the effects of an ice phase on the removal of atmospheric aerosol particles by nucleation and impaction scavenging in a convective cloud. This microphysical model—although in ...

R. R. Alheit; A. I. Flossmann; H. R. Pruppacher

1990-04-01T23:59:59.000Z

384

ARM - Field Campaign - Rain Microphysics Study with Disdrometer and  

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

govCampaignsRain Microphysics Study with Disdrometer and Polarization govCampaignsRain Microphysics Study with Disdrometer and Polarization Radar Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Rain Microphysics Study with Disdrometer and Polarization Radar 2005.04.28 - 2005.06.30 Lead Scientist : Guifu Zhang For data sets, see below. Description Understanding rain microphysics is important for accurate rainfall rate estimation and for improving parameterization in numerical weather prediction (NWP). The NCAR video disdrometer was installed at the ARM site at the Kessler farm. The disdrometer was also put side-by-side with the NSSL disdrometer for comparison/calibration and to study sampling effects. The disdrometer observations were used to verify KOUN polarimeteric radar

385

A Microphysical Interpretation of Radar Reflectivity–Rain Rate Relationships  

Science Conference Proceedings (OSTI)

The microphysical aspects of the relationship between radar reflectivity Z and rainfall rate R are examined. Various concepts discussed in the literature are integrated into a coherent analytical framework and discussed with a focus on the ...

Matthias Steiner; James A. Smith; Remko Uijlenhoet

2004-05-01T23:59:59.000Z

386

Sensitivity of Bow Echo Simulation to Microphysical Parameterizations  

Science Conference Proceedings (OSTI)

The sensitivity of a case study bow echo simulation to eight different microphysical schemes in the Weather Research and Forecasting model was tested, with a focus on graupel parameter characteristics. The graupel parameter in one scheme was ...

Rebecca D. Adams-Selin; Susan C. van den Heever; Richard H. Johnson

387

Sensitivity of Bow-Echo Simulation to Microphysical Parameterizations  

Science Conference Proceedings (OSTI)

The sensitivity of a case study bow-echo simulation to eight different microphysical schemes in the Weather Research and Forecasting model was tested, with a focus on graupel parameter characteristics. The graupel parameter in one scheme was ...

Rebecca D. Adams-Selin; Susan C. van den Heever; Richard H. Johnson

2013-10-01T23:59:59.000Z

388

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics...  

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

Aerosols in a Changing Atmosphere: From Detailed Aerosol Microphysics to Policy Applications Speaker(s): Susanne Bauer Date: December 6, 2011 - 4:00pm Location: 90-4133 Seminar...

389

Investigation of Microphysical Processes Occurring in Isolated Convection during NAME  

Science Conference Proceedings (OSTI)

To address questions regarding microphysical processes occurring in the core North American monsoon region, data from NCAR’s S-band polarimetric Doppler radar (S-Pol) deployed during the North American Monsoon Experiment (NAME) in the summer of ...

Angela K. Rowe; Steven A. Rutledge; Timothy J. Lang

2011-02-01T23:59:59.000Z

390

Toward Understanding of Differences in Current Cloud Retrievals of ARM Ground-based Measurements  

SciTech Connect

Accurate observations of cloud microphysical properties are needed for evaluating and improving the representation of cloud processes in climate models. However, large differences are found in current cloud products retrieved from ground-based remote sensing measurements using various retrieval algorithms. Understanding the differences is an important step to address uncertainties in the cloud retrievals. In this study, an in-depth analysis of nine existing ground-based cloud retrievals using ARM remote sensing measurements is carried out. We place emphasize on boundary layer overcast clouds and high level ice clouds, which are the focus of many current retrieval development efforts due to their radiative importance and relatively simple structure. Large systematic discrepancies in cloud microphysical properties are found in these two types of clouds among the nine cloud retrieval products, particularly for the cloud liquid and ice effective radius. It is shown that most of these large differences have their roots in the retrieval algorithms used by these cloud products, including the retrieval theoretical bases, assumptions, as well as input and constraint parameters. This study suggests the need to further validate current retrieval theories and assumptions and even the development of new retrieval algorithms with more observations under different cloud regimes.

Zhao, Chuanfeng; Xie, Shaocheng; Klein, Stephen A.; Protat, Alain; Shupe, Matthew D.; McFarlane, Sally A.; Comstock, Jennifer M.; Delanoe, Julien; Deng, Min; Dunn, Maureen; Hogan, Robin; Huang, Dong; Jensen, Michael; Mace, Gerald G.; McCoy, Renata; O'Conner, Ewan J.; Turner, Dave; Wang, Zhien

2012-05-30T23:59:59.000Z

391

A Global Cloud Resolving Model Goals  

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

Cloud Resolving Model Cloud Resolving Model Goals Uniform global horizontal grid spacing of 4 km or better ("cloud permitting") 100 or more layers up to at least the stratopause Parameterizations of microphysics, turbulence (including small clouds), and radiation Execution speed of at least several simulated days per wall-clock day on immediately available systems Annual cycle simulation by end of 2011. Motivations Parameterizations are still problematic. There are no spectral gaps. The equations themselves change at high resolution. GCRMs will be used for NWP within 10 years. GCRMs will be used for climate time-slices shortly thereafter. It's going to take some time to learn how to do GCRMs well. Scaling Science Length, Spatial extent, #Atoms, Weak scaling Time scale

392

Dynamical-Microphysical Evolution of a Convective Storm in a Weakly-Sheared Environment. Part I: Microphysical Observations and Interpretation  

Science Conference Proceedings (OSTI)

Aircraft measurements of microphysical thermodynamic, and vertical air motion properties supplemented by radar measurements of reflectivity structure are used to investigate precipitation development throughout much of the life cycle of a ...

James E. Dye; Brooks E. Martner; L. Jay Miller

1983-09-01T23:59:59.000Z

393

Toward understanding of differences in current cloud retrievals of ARM ground-based measurements  

SciTech Connect

Accurate observations of cloud microphysical properties are needed for evaluating and improving the representation of cloud processes in climate models and better estimate of the Earth radiative budget. However, large differences are found in current cloud products retrieved from ground-based remote sensing measurements using various retrieval algorithms. Understanding the differences is an important step to address uncertainties in the cloud retrievals. In this study, an in-depth analysis of nine existing ground-based cloud retrievals using ARM remote sensing measurements is carried out. We place emphasis on boundary layer overcast clouds and high level ice clouds, which are the focus of many current retrieval development efforts due to their radiative importance and relatively simple structure. Large systematic discrepancies in cloud microphysical properties are found in these two types of clouds among the nine cloud retrieval products, particularly for the cloud liquid and ice particle effective radius. Note that the differences among some retrieval products are even larger than the prescribed uncertainties reported by the retrieval algorithm developers. It is shown that most of these large differences have their roots in the retrieval theoretical bases, assumptions, as well as input and constraint parameters. This study suggests the need to further validate current retrieval theories and assumptions and even the development of new retrieval algorithms with more observations under different cloud regimes.

Zhao C.; Dunn M.; Xie, S.; Klein, S. A.; Protat, A.; Shupe, M. D.; McFarlane, S. A.; Comstock, J. M.; Delanoė, J.; Deng, M.; Hogan, R. J.; Huang, D.; Jensen, M. P.; Mace, G. G.; McCoy, R.; O’Connor, E. J.; Turner, D. D.; Wang, Z.

2012-05-30T23:59:59.000Z

394

Sensitivity of PDR Calculations to Microphysical Details  

E-Print Network (OSTI)

Our understanding of physical processes in Photodissociation regions or Photon Dominated Regions (PDRs) largely depends on the ability of spectral synthesis codes to reproduce the observed infrared emission-line spectrum. In this paper, we explore the sensitivity of a single PDR model to microphysical details. Our calculations use the Cloudy spectral synthesis code, recently modified to include a wealth of PDR physical processes. We show how the chemical/thermal structure of a PDR, along with the calculated spectrum, changes when the treatment of physical processes such as grain physics and atomic/molecular rates are varied. We find a significant variation in the intensities of PDR emission lines, depending on different treatments of the grain physics. We also show how different combinations of the cosmic-ray ionization rate, inclusion of grain-atom/ion charge transfer, and the grain size distribution can lead to very similar results for the chemical structure. Additionally, our results show the utility of Cloudy for the spectral modeling of molecular environments.

N. P. Abel; P. A. M. van Hoof; G. Shaw; G. J. Ferland; T. Elwert

2008-08-19T23:59:59.000Z

395

Continental Liquid-phase Stratus Clouds at SGP: Meteorological Influences  

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

Continental Liquid-phase Stratus Clouds at SGP: Meteorological Influences Continental Liquid-phase Stratus Clouds at SGP: Meteorological Influences and Relationship to Adiabacity Kim, Byung-Gon Kangnung National University Schwartz, Stephen Brookhaven National Laboratory Miller, Mark Brookhaven National Laboratory Min, Qilong State University of New York at Albany Category: Cloud Properties The microphysical properties of continental stratus clouds observed over SGP appear to be substantially influenced by micrometeorological conditions, such as static stability and updraft velocity. These influences may contribute to the observed weak correlation of aerosol light scattering coefficient with cloud-drop effective radius [Kim et al., JGR, 2003], although aerosol light scattering coefficient is not necessarily the most suitable surrogate aerosol property for number concentration of cloud

396

ARM - Publications: Science Team Meeting Documents  

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

Simulations of Mixed-Phase Altocumulus: An Evaluation of Remote Sensing Simulations of Mixed-Phase Altocumulus: An Evaluation of Remote Sensing Properties Versus Relative Ice/Water Content Sassen, K.(a) and Khvorostyanov, V.I.(b), University of Alaska Faibanks (a), Moscow Central Aerological Observatory (b) Mixed-phase clouds are acknowledged to be a harsh test of remote sensing data-based algorithms designed to derive microphysical and radiative properties. Yet, such clouds are globally ubiquitous. Using a 2-D cloud model with explicit microphysics and radiation, we evaluate the changes in mixed phase clouds caused by increasing ice content until glaciation occurs. The properties of the ice and water particle constituents are resolved independently, revealing the relative radiative contributions from the water phase source cloud versus the ice phase virga. Cloud contents are

397

Statistical representation of clouds in climate models  

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

novel approach for representing novel approach for representing ice microphysics in bin and bulk schemes: Application to TWP-ICE deep convection Hugh Morrison and Wojciech Grabowski National Center for Atmospheric Research ARM STM, Monday, April 1, 2009 -1) Uncertainty of ice initiation processes -2) Wide range of ice particle characteristics (e.g., shape, effective density) -3) No clear separation of physical processes for small and large crystals The treatment of ice microphysics has a large impact on model simulations, e.g., precipitation, interactions with dynamics, radiation, etc. However, it is complicated by: Pristine ice crystals, grown by diffusion of water vapor Snowflakes, grown by aggregation Pruppacher and Klett Rimed ice crystals (accretion of supercooled cloud water) Graupel (heavily

398

Influence of Electrification on Microphysical and Dynamical Processes in a Numerically Simulated Thunderstorm  

Science Conference Proceedings (OSTI)

A new three-dimensional dynamics and electrification coupled model is developed to investigate the influence of electrification on microphysical and dynamical processes in thunderstorms. This model includes a four-class ice microphysics scheme, ...

Anping Sun; Hye-Yeong Chun; Jong-Jin Baik; Muhong Yan

2002-11-01T23:59:59.000Z

399

TRMM Common Microphysics Products: A Tool for Evaluating Spaceborne Precipitation Retrieval Algorithms  

Science Conference Proceedings (OSTI)

A customized product for analysis of microphysics data collected from aircraft during field campaigns in support of the Tropical Rainfall Measuring Mission (TRMM) program is described. These “common microphysics products” (CMPs) are designed to ...

David E. Kingsmill; Sandra E. Yuter; Andrew J. Heymsfield; Peter V. Hobbs; Alexei V. Korolev; Stith Jeffrey L; Aaron Bansemer; Julie A. Haggerty; Arthur L. Rangno

2004-11-01T23:59:59.000Z

400

Study of ice cloud properties using infrared spectral data  

E-Print Network (OSTI)

The research presented in this thesis involves the study of ice cloud microphysical and optical properties using both hyperspectral and narrowband infrared spectral data. First, ice cloud models are developed for the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the METOP-A satellite, which provide the bulk-scattering properties of these clouds for the 8461 IASI channels between 645 and 2760 cm-1. We investigate the sensitivity of simulated brightness temperatures in this spectral region to the bulk-scattering properties of ice clouds containing individual ice crystal habits as well as for one habit distribution. The second part of this thesis describes an algorithm developed to analyze the sensitivity of simulated brightness temperatures at 8.5 and 11.0 µm to changes in effective cloud temperature by adjusting cloud top height and geometric thickness in a standard tropical atmosphere. Applicability of using these channels in a bi-spectral approach to retrieve cirrus cloud effective particle size and optical thickness is assessed. Finally, the algorithm is applied to the retrieval of these ice cloud properties for a case of single-layered cirrus cloud over a tropical ocean surface using measurements from the Moderate Resolution Infrared Spectroradiometer (MODIS). Cloud top height and geometric thickness in the profile are adjusted to assess the influence of effective cloud temperature on the retrieval.

Garrett, Kevin James

2007-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

402

Radiative Transfer to Space through a Precipitating Cloud at Multiple Microwave Frequencies. Part I: Model Description  

Science Conference Proceedings (OSTI)

In a two-part study we investigate the impact of time-dependent cloud microphysical structure on the transfer to space of passive microwave radiation at several frequencies across the EHF and lower SHF portions of the microwave spectrum in order ...

Alberto Mugnai; Eric A. Smith

1988-09-01T23:59:59.000Z

403

Shattering and Particle Interarrival Times Measured by Optical Array Probes in Ice Clouds  

Science Conference Proceedings (OSTI)

Optical array probes are one of the most important tools for determining the microphysical structure of clouds. It has been known for some time that the shattering of ice crystals on the housing of these probes can lead to incorrect measurements ...

P. R. Field; A. J. Heymsfield; A. Bansemer

2006-10-01T23:59:59.000Z

404

A Comparison of AgI and CO2 Seeding Effects in Alberta Cumulus Clouds  

Science Conference Proceedings (OSTI)

Three convective clouds extending above a stratocumulus layer were identified as being seedable on one day and were then seeded in a random sequence with CO2 pellets, a placebo and droppable AgI flares. The radar and microphysical seeding effects ...

Marianne English; John D. Marwitz

1981-05-01T23:59:59.000Z

405

Two-Time-Level Semi-Lagrangian Modeling of Precipitating Clouds  

Science Conference Proceedings (OSTI)

This paper discusses two-time-level semi-Lagrangian approximations for the bulk warm-rain microphysics embedded in the framework of an anelastic cloud model. The central theoretical issue is a semi-Lagrangian integration of the rain-evolution ...

Wojciech W. Grabowski; Piotr K. Smolarkiewicz

1996-03-01T23:59:59.000Z

406

Posters A Stratiform Cloud Parameterization for General Circulation Models  

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

Posters A Stratiform Cloud Parameterization for General Circulation Models S. J. Ghan and L. R. Leung Pacific Northwest Laboratory Richland, Washington C. C. Chuang and J. E. Penner Lawrence Livermore National Laboratory Livermore, California J. McCaa University of Washington Seattle, Washington The crude treatment of clouds in general circulation models (GCMs) is widely recognized as a major limitation in applying these models to predictions of global climate change. The purpose of this project is to develop a parameterization for stratiform clouds in GCMs that expresses stratiform clouds in terms of bulk microphysical properties and their subgrid variability. In this parameterization, precipitating cloud species are distinguished from non-precipitating species, and the liquid

407

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

408

Evaluate the Effect of Upper-Level Cirrus Clouds on Satellite Retrievals of Low-Level Cloud Droplet Effective Radius  

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

the Effect of Upper-Level Cirrus Clouds the Effect of Upper-Level Cirrus Clouds on Satellite Retrievals of Low-Level Cloud Droplet Effective Radius F.-L. Chang and Z. Li Earth System Science Interdisciplinary Center University of Maryland College Park, Maryland Z. Li Department of Meteorology University of Maryland College Park, Maryland Introduction The earth's radiation budget is sensitive to changes in the microphysical properties of low-level stratiform clouds. Their extensive coverage can significantly reduce the solar energy absorbed by the earth system. An estimate of reducing the global-mean droplet effective radius (r e ) of these low-level clouds by ~2 Āµm, while keeping the column liquid water constant would balance the warming due to CO 2 doubling in the atmosphere (Slingo 1990). Accurate determination of the droplet r

409

Prediction of Graupel Density in a Bulk Microphysics Scheme  

Science Conference Proceedings (OSTI)

A method to predict the bulk density of graupel ?g has been added to the two-moment Milbrandt–Yau bulk microphysics scheme. The simulation of graupel using the modified scheme is illustrated through idealized simulations of a mesoscale convective ...

Jason A. Milbrandt; Hugh Morrison

2013-02-01T23:59:59.000Z

410

MATRIX (Multiconfiguration Aerosol TRacker of mIXing state): an aerosol microphysical module for global atmospheric models  

SciTech Connect

A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) are described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations. A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 {micro}m, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment. This is more likely due to oversimplifications of the representation of sea salt emissions - sea salt emissions are only calculated for two size classes - than to inherent limitations of MATRIX.

Bauer,S.E.; Wright, D.L.; Koch, D.; Lewis, E.R.; McGraw, R.; Chang, L.-S.; Schwartz, S.E.; Ruedy, R.

2008-10-21T23:59:59.000Z

411

Bench-Scale Cross Flow Filtration of  

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

2 2 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 September 2007 Xiaohong Liu and Steven J. Ghan Pacific Northwest National Laboratory Richland, Washington Shaocheng Xie, James Boyle, and Stephen A. Klein 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. Liu et al., September 2007, DOE/SC-ARM/P-07-012 Summary 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,

412

Posters Ship-Based Measurements of Cloud Optical Properties  

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

7 7 Posters Ship-Based Measurements of Cloud Optical Properties During the Atlantic Stratocumulus Transition Experiment A. B. White Cooperative Institute for Research in Environmental Sciences University of Colorado at Boulder National Oceanic and Atmospheric Administration Boulder, Colorado C. W. Fairall National Oceanic and Atmospheric Administration Environmental Research Laboratories Environmental Technology Laboratory Boulder, Colorado Introduction The Atlantic Stratocumulus Transition Experiment (ASTEX), conducted in June 1992, was designed with the broad goal of improving the dynamical, radiative, and microphysical models of marine boundary layer (MBL) clouds. This goal was pursued by combining measurements from a number of different platforms including aircraft,

413

Single-Column Modeling A Stratiform Cloud Parameterization for General Circulation Models  

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

A Stratiform Cloud Parameterization A Stratiform Cloud Parameterization for General Circulation Models S. J. Ghan and L. R. Leung Pacific Northwest Laboratory Richland, WA 99352 C. C. Chuang and J. E. Penner Lawrence Livermore National Laboratory : Livermore. CA 94550 J. McCaa University of Washington Seattle, Washington The crude treatment of clouds in general circulation models (GCMs) is widely recognized as a major limitation in applying these models to predictions of global climate change. The purpose of this project is to develop in GCMs a stratiform cloud parameterization that expresses clouds in terms of bulk microphysical properties and their subgrid variability. Figure 1 summarizes the various cloud variables and their interactions. Precipitating cloud species are distinguished from non-precipitating species, and the liquid phase is

414

ARM - Field Campaign - Ground-based Cloud Tomography Experiment at SGP  

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

govCampaignsGround-based Cloud Tomography Experiment at SGP govCampaignsGround-based Cloud Tomography Experiment at SGP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Ground-based Cloud Tomography Experiment at SGP 2009.05.26 - 2009.07.17 Lead Scientist : Dong Huang For data sets, see below. Description Knowledge of 3D cloud properties is pressingly needed in many research fields. One of the problems encountered when trying to represent 3D cloud fields in numerical models is that the existing techniques cannot provide necessary observations at the required spatial scale and resolution. We tested a new promising technique for measuring 3D cloud microphysical structure, called cloud microwave tomography, at the Southern Great Plains (SGP) site for one month in late April 2009. Five microwave scanning

415

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

416

Modeling aerosol growth by aqueous chemistry in nonprecipitating stratiform cloud  

SciTech Connect

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

Ovchinnikov, Mikhail; Easter, Richard C.

2010-07-29T23:59:59.000Z

417

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...

418

ARM - Field Campaign - Biogenic Aerosols - Effects on Clouds and Climate:  

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

govCampaignsBiogenic Aerosols - Effects on Clouds and Climate: Snowfall govCampaignsBiogenic Aerosols - Effects on Clouds and Climate: Snowfall Experiment Related Campaigns Biogenic Aerosols- Effects on Clouds and Climate 2014.02.01, PetƤjƤ, AMF Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Biogenic Aerosols - Effects on Clouds and Climate: Snowfall Experiment 2014.02.01 - 2014.04.30 Lead Scientist : Dmitri Moisseev Description The snowfall measurement campaign, which will take place during AMF2 deployment in Finland, will focus on understanding snowfall microphysics and characterizing performance of surface based snowfall measurement instruments. This will be achieved by combining triple frequency (X, Ka, W -band) radar observations of vertical structure of the precipitation,

419

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

420

The Influence of Entrainment and Mixing on the Initial Formation of Rain in a Warm Cumulus Cloud  

Science Conference Proceedings (OSTI)

The objective of this study is to address the problem of the production of rain in warm cumulus clouds that has been observed to occur within about 20 min. A hybrid model approach is used where a microphysical parcel model is run along ...

William A. Cooper; Sonia G. Lasher-Trapp; Alan M. Blyth

2013-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

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

422

SCM Working Group  

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

cloud microphysical parameterizations cloud microphysical parameterizations with SCM, CAPT and M-PACE observations X. Liu (PNNL) S. Xie, J. Boyle, S. Klein (LLNL) S. J. Ghan (PNNL) H. Morrison, A. Gettelman (NCAR) Goal: Improve Climate Model Parameterizations Tools: single column models (SCM) and DOE CCPP-ARM Parameterization Testbed (CAPT) (LLNL CAPT team) ARM measurements provide unique data for model evaluation and guidance for parameterization improvement Motivations Cloud microphysics in mixed-phase clouds has a significant impact on cloud radiative forcing, precipitation formation, etc. The treatment of mixed-phase clouds in most current climate models is often oversimplified Liquid/ice partitioning according to a temperature dependent function; Neglect ice nucleation and Bergeron-Findeisen

423

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

424

Model simulations of the first aerosol indirect effect and comparison of cloud susceptibility fo satellite measurements  

DOE Green Energy (OSTI)

Present-day global anthropogenic emissions contribute more than half of the mass in submicron particles primarily due to sulfate and carbonaceous aerosol components derived from fossil fuel combustion and biomass burning. These anthropogenic aerosols modify the microphysics of clouds by serving as cloud condensation nuclei (CCN) and enhance the reflectivity of low-level water clouds, leading to a cooling effect on climate (the Twomey effect or first indirect effect). The magnitude of the first aerosol indirect effect is associated with cloud frequency as well as a quantity representing the sensitivity of cloud albedo to changes in cloud drop number concentration. This quantity is referred to as cloud susceptibility [Twomey, 1991]. Analysis of satellite measurements demonstrates that marine stratus clouds are likely to be of higher susceptibility than continental clouds because of their lower number concentrations of cloud drops [Platnick and Twomey, 1994]. Here, we use an improved version of the fully coupled climate/chemistry model [Chuang et al., 1997] to calculate the global concentrations Of sulfate, dust, sea salt, and carbonaceous aerosols (biomass smoke and fossil fuel organic matter and black carbon). We investigated the impact of anthropogenic aerosols on cloud susceptibility and calculated the associated changes of shortwave radiative fluxes at the top of the atmosphere. We also examined the correspondence between the model simulation of cloud susceptibility and that inferred from satellite measurements to test whether our simulated aerosol concentrations and aerosol/cloud interactions give a faithful representation of these features.

Chuang, C; Penner, J E; Kawamoto, K

2002-03-08T23:59:59.000Z

425

Atmos. Chem. Phys., 13, 49634982, 2013 www.atmos-chem-phys.net/13/4963/2013/  

E-Print Network (OSTI)

Access Solid Earth OpenAccess The Cryosphere OpenAccess Evaluating and constraining ice cloud parameterizations are performed with two different ice nucleation schemes for pure ice-phase clouds. One of the schemes can of perturbing these parameters is also dis- cussed. 1 Introduction Microphysical processes in ice- and mixed-phase

Meskhidze, Nicholas

426

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

E-Print Network (OSTI)

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

Bauer, Susanne E.

2010-01-01T23:59:59.000Z

427

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

428

Microphysical Structure of the Marine Boundary Layer under Strong Wind and Spray Formation as Seen from Simulations Using a 2D Explicit Microphysical Model. Part I: The Impact of Large Eddies  

Science Conference Proceedings (OSTI)

The effects of large eddies (LE) on the marine boundary layer (MBL) microphysics and thermodynamics is investigated using a 2D Lagrangian model with spectral bin microphysics including effects of sea spray. The 600 m × 400 m MBL computational area ...

J. Shpund; M. Pinsky; A. Khain

2011-10-01T23:59:59.000Z

429

The Analysis and Prediction of Microphysical States and Polarimetric Radar Variables in a Mesoscale Convective System Using Double-Moment Microphysics, Multi-Network Radar Data, and the Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

Doppler radar data are assimilated with an ensemble Kalman Filter (EnKF) in combination with a double-moment (DM) microphysics scheme in order to improve the analysis and forecast of microphysical states and precipitation structures within a ...

Bryan J. Putnam; Ming Xue; Youngsun Jung; Nathan Snook; Guifu Zhang

430

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

431

Research Highlight  

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

Mixed-Phase Cloud Radiative Properties from M-PACE Microphysical Retrievals Mixed-Phase Cloud Radiative Properties from M-PACE Microphysical Retrievals Download a printable PDF Submitter: de Boer, G., University of Colorado, Boulder/CIRES Area of Research: Radiation Processes Working Group(s): Cloud Life Cycle Journal Reference: de Boer G, WD Collins, S Menon, and CN Long. 2011. "Using surface remote sensors to derive radiative characteristics of mixed-phase clouds: An example from M-PACE." Atmospheric Chemistry and Physics, 11, doi: 10.5194/acp-11-11937-2011. Measured and retrieved cloud properties on 10 October 2004. Included are (top to bottom) AHSRL bacscatter cross-section, AHSRL depolarization ratio, MMCR reflectivity, and profiles of liquid water content (LWC), ice water content (IWC), and liquid (r_{e,liq}) and ice (r$_{e,ice}$) effective

432

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

433

The 12/13 January 1988 Narrow Cold-Frontal Rainband Observed during MFDP/FRONTS 87. Part II: Microphysics  

Science Conference Proceedings (OSTI)

The microphysics of a narrow cold-frontal rainband (NCFR) observed during the MFDP/FRONTS87 experiment is investigated by using a microphysical retrieval model. The equations of evolution of the water substance and of the temperature are solved ...

Virginie Marécal; Daničle Hauser; Frank Roux

1993-04-01T23:59:59.000Z

434

The 4–5 December 2001 IMPROVE-2 Event: Observed Microphysics and Comparisons with the Weather Research and Forecasting Model  

Science Conference Proceedings (OSTI)

This paper highlights the observed and simulated microphysical evolution of a moderate orographic rainfall event over the central Oregon Cascade Range during 4–5 December 2001 of the Second Improvement of Microphysical Parameterization through ...

Yanluan Lin; Brian A. Colle

2009-04-01T23:59:59.000Z

435

The 13–14 December 2001 IMPROVE-2 Event. Part III: Simulated Microphysical Budgets and Sensitivity Studies  

Science Conference Proceedings (OSTI)

This paper investigates the microphysical pathways and sensitivities within the Reisner-2 bulk microphysical parameterization (BMP) of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) ...

Brian A. Colle; Matthew F. Garvert; Justin B. Wolfe; Clifford F. Mass; Christopher P. Woods

2005-10-01T23:59:59.000Z

436

Microphysical Effects of Irradiating a Fog With a 10.6-? CO2 Laser  

Science Conference Proceedings (OSTI)

The microphysical effects due to illuminating a fog with a 10.6-?m CO2 laser are examined using a microphysical model that accounts for the sensible and latent heat transfers from the drop and the absorption of the laser energy by the liquid ...

Kenneth C. Young; Ed Tomlinson

1993-04-01T23:59:59.000Z

437

Microphysical and Optical Properties of Cirrus and Contrails: Cloud Field Study on 13 October 1989  

Science Conference Proceedings (OSTI)

During the intensive International Cirrus Experiment conducted over the North Sea during fall 1989, natural cirrus and contrail-induced cirrus were analyzed from in situ and remote sensing measurements (lidar and infrared radiometer). These two ...

Jean-Franēois Gayet; Guy Febvre; Gerard Brogniez; Helene Chepfer; Wolfgang Renger; Peter Wendling

1996-01-01T23:59:59.000Z

438

Effect of Amazon Smoke on Cloud Microphysics and Albedo-Analysis from Satellite Imagery  

Science Conference Proceedings (OSTI)

NOAA Advanced Very High Resolution Radiometer images taken over the Brazilian Amazon Basin during the biomass burning season of 1987 are used to study the effect of smoke aerosol particles on the properties of low cumulus and stratocumulus ...

Yoram J. Kaufman; Teruyuki Nakajima

1993-04-01T23:59:59.000Z

439

Stratospheric Ion and Aerosol Chemistry and Possible Links with Cirrus Cloud Microphysics—A Critical Assessment  

Science Conference Proceedings (OSTI)

It has been postulated that variations in galactic cosmic rays could affect production of stratospheric aerosols which, after transport to the upper troposphere, could affect latent heat release in convective and cyclonic systems. This hypothesis ...

Volker A. Mohnen

1990-08-01T23:59:59.000Z

440

A New Approach for Estimating Entrainment Rate in Cumulus Clouds  

SciTech Connect

A new approach is presented to estimate entrainment rate in cumulus clouds. The new approach is directly derived from the definition of fractional entrainment rate and relates it to mixing fraction and the height above cloud base. The results derived from the new approach compare favorably with those obtained with a commonly used approach, and have smaller uncertainty. This new approach has several advantages: it eliminates the need for in-cloud measurements of temperature and water vapor content, which are often problematic in current aircraft observations; it has the potential for straightforwardly connecting the estimation of entrainment rate and the microphysical effects of entrainment-mixing processes; it also has the potential for developing a remote sensing technique to infer entrainment rate.

Lu C.; Liu, Y.; Yum, S. S.; Niu, S.; Endo, S.

2012-02-16T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Aerosols and clouds in chemical transport models and climate models.  

Science Conference Proceedings (OSTI)

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

Lohmann,U.; Schwartz, S. E.

2008-03-02T23:59:59.000Z

442

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

443

A Study of Thunderstorm Microphysics with Multiparameter Radar and Aircraft Observations  

Science Conference Proceedings (OSTI)

Excellent agreement was found between multiparameter radar signatures of hail, raindrops, and mixed-phase precipitation and in situ precipitation particle measurements made by aircraft in a northeastern Colorado hail-storm. Radar reflectivity ...

E. A. Brandes; J. Vivekanandan; J. D. Tuttle; C. J. Kessinger

1995-11-01T23:59:59.000Z

444

Effects of aerosols on deep convective cumulus clouds  

E-Print Network (OSTI)

This work investigates the effects of anthropogenic aerosols on deep convective clouds and the associated radiative forcing in the Houston area. The Goddard Cumulus Ensemble model (GCE) coupled with a spectral-bin microphysics is employed to investigate the aerosol effects on clouds and precipitation. First, aerosol indirect effects on clouds are separately investigated under different aerosol compositions, concentrations and size distributions. Then, an updated GCE model coupled with the radiative transfer and land surface processes is employed to investigate the aerosol radiative effects on deep convective clouds. The cloud microphysical and macrophysical properties change considerably with the aerosol properties. With varying the aerosol composition from only (NH4)2SO4, (NH4)2SO4 with soluble organics, to (NH4)2SO4 with slightly soluble organics, the number of activated aerosols decreases gradually, leading to a decrease in the cloud droplet number concentration (CDNC) and an increase in the droplet size. Ice processes are more sensitive to the changes of aerosol chemical properties than the warm rain processes. The most noticeable effect of increasing aerosol number concentrations is an increase of CDNC and cloud water content but a decrease in droplet size. It is indicated that the aerosol indirect effect on deep convection is more pronounced in relatively clean air than in heavily polluted air. The aerosol effects on clouds are strongly dependent on RH: the effect is very significant in humid air. Aerosol radiative effects (ARE) on clouds are very pronounced for mid-visible single-scattering albedo (SSA) of 0.85. Relative to the case without the ARE, cloud fraction and optical depth decrease by about 18% and 20%, respectively. The daytime-mean direct forcing is about 2.2 W m-2 at the TOA and -17.4 W m-2 at the surface. The semi-direct forcing is positive, about 10 and 11.2 W m-2 at the TOA and surface, respectively. Aerosol direct and semi-direct effects are very sensitive to SSA. The cloud fraction, optical depth, convective strength, and precipitation decrease with the increase of absorption, resulting from a more stable atmosphere due to enhanced surface cooling and atmospheric heating.

Fan, Jiwen

2007-08-01T23:59:59.000Z

445

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

446

ARM - Field Campaign - 2008 VAMOS Ocean-Cloud-Atmos-Land Study (VOCALS)  

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

8 VAMOS Ocean-Cloud-Atmos-Land Study (VOCALS) 8 VAMOS Ocean-Cloud-Atmos-Land Study (VOCALS) Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : 2008 VAMOS Ocean-Cloud-Atmos-Land Study (VOCALS) 2008.10.14 - 2008.11.13 Lead Scientist : Peter Daum For data sets, see below. Description The DOE G-1 aircraft was deployed to Arica, Chile as part of the NSF VAMOS Ocean-Cloud- Atmospheric-Land Study (VOCALS). The purpose of VOCALS is to develop an understanding of the physical and chemical processes central to the climate system of the Southeast Pacific. In this region, extensive areas of marine clouds exist (coverage about 70% in October). The ASP component of VOCALS focused on aerosols, and how their chemical and microphysical properties, and their ability to act as CCN differ between

447

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,

448

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

449

Microphysical Characteristics of a Well-Developed Weak Echo Region in a High Plains Supercell Thunderstorm  

Science Conference Proceedings (OSTI)

Microphysical measurements in and near the weak echo region of a supercell thunderstorm are discussed. The observations were made in southeastern Montana with an armored T-28 aircraft, which has the capability to measure hydrometeors over almost ...

Dennis J. Musil; Andrew J. Heymsfield; Paul L. Smith

1986-07-01T23:59:59.000Z

450

The 29 June 2000 Supercell Observed during STEPS. Part I: Kinematics and Microphysics  

Science Conference Proceedings (OSTI)

This is a two-part study that addresses the kinematic, microphysical, and electrical aspects of a severe storm that occurred in western Kansas on 29 June 2000 observed during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) ...

Sarah A. Tessendorf; L. Jay Miller; Kyle C. Wiens; Steven A. Rutledge

2005-12-01T23:59:59.000Z

451

Predicting the Snow-to-Liquid Ratio of Surface Precipitation Using a Bulk Microphysics Scheme  

Science Conference Proceedings (OSTI)

Bulk microphysics parameterizations play an increasingly important role for quantitative precipitation forecasting (QPF) in operational numerical weather prediction (NWP). For wintertime, numerical prediction of snowfall amounts is done by ...

J. A. Milbrandt; A. Glazer; D. Jacob

2012-08-01T23:59:59.000Z

452

A Multimoment Bulk Microphysics Parameterization. Part I: Analysis of the Role of the Spectral Shape Parameter  

Science Conference Proceedings (OSTI)

With increasing computer power, explicit microphysics schemes are becoming increasingly important in atmospheric models. Many schemes have followed the approach of Kessler in which one moment of the hydrometeor size distribution, proportional to ...

J. A. Milbrandt; M. K. Yau

2005-09-01T23:59:59.000Z

453

Rain Gauge and Disdrometer Measurements during the Keys Area Microphysics Project (KAMP)  

Science Conference Proceedings (OSTI)

Four impact disdrometers and 27 tipping bucket rain gauges were operated at 11 different sites during August and September 2001, as part of the Keys Area Microphysics Project. The rain gauge and disdrometer network was designed to study the range ...

Ali Tokay; David B. Wolff; Katherine R. Wolff; Paul Bashor

2003-11-01T23:59:59.000Z

454

A Multisensor Approach Toward a Better Understanding of Snowfall Microphysics: The TOSCA Project  

Science Conference Proceedings (OSTI)

The Towards an Optimal estimation based Snow Characterization Algorithm (TOSCA) project addresses possible novel measurement synergies for deriving snowfall microphysical parameters from the ground by combining the unique information obtained from a suite ...

U. Löhnert; S. Kneifel; A. Battaglia; M. Hagen; L. Hirsch; S. Crewell

2011-05-01T23:59:59.000Z

455

Winter Storms over the San Juan Mountains. Part II: Microphysical Processes  

Science Conference Proceedings (OSTI)

Airborne observations of wintertime storms in southeastern Colorado have shown that the microphysical structure of those storms evolved in close relationship to the dynamical structure. The storms evolved from deep synoptic-scale systems to ...

William A. Cooper; Clive P. R. Saunders

1980-08-01T23:59:59.000Z

456

Numerical Simulations of the 2 August 1981 CCOPE Supercell Storm with and without Ice Microphysics  

Science Conference Proceedings (OSTI)

The Wisconsin Dynamical-Microphysical Model is used in two simulations of the 2 August 1981 supercell that passed through the Cooperative Convective Precipitation Experiment in southeastern Montana. The first simulation uses liquid water-only ...

Daniel E. Johnson; Pao K. Wang; Jerry M. Straka

1993-04-01T23:59:59.000Z

457

Role of a Parameterized Ice-Phase Microphysics in an Axisymmetric, Nonhydrostatic Tropical Cyclone Model  

Science Conference Proceedings (OSTI)

Results of an axisymmetric, nonhydrostatic hurricane model are analyzed with emphasis on the role of a parameterized ice-phase microphysics Inclusion of ice processes produces dramatic differences in the structure and evolution of the simulated ...

Stephen J. Lord; Hugh E. Willoughby; Jacqueline M. Piotrowicz

1984-10-01T23:59:59.000Z

458

Impact of Two Microphysical Schemes upon Gas Scavenging and Deposition in a Mesoscale Meteorological Model  

Science Conference Proceedings (OSTI)

Two widely used microphysical schemes are compared to evaluate their possible impact on wet deposition mechanisms. They are based upon different spectral distributions for raindrops (Marshall-Palmer and lognormal distributions) and use different ...

Nadine Chaumerliac; Evelyne Richard; Robert Rosset; Everett C. Nickerson

1991-01-01T23:59:59.000Z

459

An Approach for Convective Parameterization with Memory: Separating Microphysics and Transport in Grid-Scale Equations  

Science Conference Proceedings (OSTI)

An approach for convective parameterization is presented here, in which grid-scale budget equations of parameterization use separate microphysics and transport terms. This separation is used both as a way to introduce into the parameterization a ...

Jean-Marcel Piriou; Jean-Luc Redelsperger; Jean-Franēois Geleyn; Jean-Philippe Lafore; Franēoise Guichard

2007-11-01T23:59:59.000Z

460

Wind Profiler Observations of Vertical Motion and Precipitation Microphysics of a Tropical Squall Line  

Science Conference Proceedings (OSTI)

Data from a wind profiler located at Darwin, Australia, have been used to examine the vertical motions and precipitation microphysics in a well-developed squall line. Both a mature and developing convective cell are well sampled. The vertical ...

Peter T. May; Deepak K. Rajopadhyaya

1996-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

A New Bulk Microphysical Scheme That Includes Riming Intensity and Temperature-Dependent Ice Characteristics  

Science Conference Proceedings (OSTI)

A new bulk microphysical parameterization (BMP) scheme is presented that includes a diagnosed riming intensity and its impact on ice characteristics. As a result, the new scheme represents a continuous spectrum from pristine ice particles to ...

Yanluan Lin; Brian A. Colle

2011-03-01T23:59:59.000Z

462

Systematic Biases in the Microphysics and Thermodynamics of Numerical Models That Ignore Subgrid-Scale Variability  

Science Conference Proceedings (OSTI)

A grid box in a numerical model that ignores subgrid variability has biases in certain microphysical and thermodynamic quantities relative to the values that would be obtained if subgrid-scale variability were taken into account. The biases are ...

Vincent E. Larson; Robert Wood; Paul R. Field; Jean-Christophe Golaz; Thomas H. Vonder Haar; William R. Cotton

2001-05-01T23:59:59.000Z

463

Relations of Kinematics, Microphysics and Electrification in an Isolated Mountain Thunderstorm  

Science Conference Proceedings (OSTI)

This paper addresses aspects of the airflow, microphysics, and electrification in a mountain thunderstorm which occurred on 7 August 1979 over the Langmuir Laboratory new Socorro, New Mexico, site of the Thunderstorm Research International ...

Conrad L. Ziegler; Peter S. Ray; Donald R. MacGorman

1986-10-01T23:59:59.000Z

464

A Method for Adaptive Habit Prediction in Bulk Microphysical Models. Part I: Theoretical Development  

Science Conference Proceedings (OSTI)

Bulk microphysical schemes use the capacitance model for ice vapor growth in combination with mass–size relationships to determine the evolution of ice water content (IWC) and ice particle maximum dimension in time. These approaches are limited ...

Jerry Y. Harrington; Kara Sulia; Hugh Morrison

2013-02-01T23:59:59.000Z

465

Microphysics of Maritime Tropical Convective Updrafts at Temperatures from ?20° to ?60°  

Science Conference Proceedings (OSTI)

Anvils produced by vigorous tropical convection contribute significantly to the earth’s radiation balance, and their radiative properties depend largely on the concentrations and sizes of the ice particles that form them. These microphysical ...

Andrew J. Heymsfield; Aaron Bansemer; Gerald Heymsfield; Alexandre O. Fierro

2009-12-01T23:59:59.000Z

466

Microphysical Characteristics of Three Anvils Sampled during the Central Equatorial Pacific Experiment  

Science Conference Proceedings (OSTI)

In situ microphysical measurements of three anvils were made 17 March, 1 April, and 4 April 1993 during the Central Equatorial Pacific Experiment for several constant altitude penetrations, in the same direction or opposite the ambient wind, from ...

Greg M. McFarquhar; Andrew J. Heymsfield

1996-09-01T23:59:59.000Z

467

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

468

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

469

A Microphysical Retrieval Scheme for Continental Low-Level Stratiform Clouds: Impacts of the Subadiabatic Character on Microphysical Properties and Radiation Budgets  

Science Conference Proceedings (OSTI)

Using measurements from the Department of Energy’s Atmospheric Radiation Measurement Program, a modified ground-based remote sensing technique is developed and evaluated to study the impacts of the subadiabatic character of continental low-level ...

Hung-Neng S. Chin; Daniel J. Rodriguez; Richard T. Cederwall; Catherine C. Chuang; Allen S. Grossman; John J. Yio; Qiang Fu; Mark A. Miller

2000-07-01T23:59:59.000Z

470

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

471

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

472

A Large-Droplet Mode and Prognostic Number Concentration of Cloud Droplets in the Colorado State University Regional Atmospheric Modeling System (RAMS). Part II: Sensitivity to a Colorado Winter Snowfall Event  

Science Conference Proceedings (OSTI)

This paper is the second in a two-part series describing recent additions to the microphysics module of the Regional Atmospheric Modeling System (RAMS) at Colorado State University. These changes include the addition of a large-cloud-droplet mode ...

Stephen M. Saleeby; William R. Cotton

2005-12-01T23:59:59.000Z

473

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

474

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

475

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...

476

Microphysical Structure of the Marine Boundary Layer under Strong Wind and Spray Formation as Seen from Simulations Using a 2D Explicit Microphysical Model. Part II: The Role of Sea Spray  

Science Conference Proceedings (OSTI)

The effect of sea spray on the thermodynamics and microphysical structure of the lowest 400-m layer under strong wind speeds is investigated using a 2D hybrid Lagrangian–Eulerian model with spectral bin microphysics. A large number of adjacent and ...

J. Shpund; J. A. Zhang; M. Pinsky; A. Khain

2012-12-01T23:59:59.000Z

477

ARM - Publications: Science Team Meeting Documents  

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

High Latitude Cloud Microphysical Properties from FTIR Data High Latitude Cloud Microphysical Properties from FTIR Data Lubin, D., Scripps Institution of Oceanography Thirteenth Atmospheric Radiation Measurement (ARM) Science Team Meeting The ARM AERI instruments record downwelling radiance spectra with sufficient radiometric calibration to enable the retrieval of important cloud microphysical properties. This poster will describe how radiative transfer simulations that include cloud thermodynamic phase (liquid water, ice, mixed phase) can be utilized with Fourier Transform Infrared (FTIR) spectroradiometer data. The presence of the ice phase in cloud alters the slope of the brightness temperature spectrum between 800 - 1200 inverse centimeters, such that ice can often be detected. The AERI near infrared channel also may have potential for cloud phase as discrimination.

478

Simulation of an Orographic Precipitation Event during IMPROVE-2. Part I: Evaluation of the Control Run Using a Triple-Moment Bulk Microphysics Scheme  

Science Conference Proceedings (OSTI)

This paper reports the first evaluation of the Milbrandt–Yau multimoment bulk microphysics scheme against in situ microphysical measurements. The full triple-moment version of the scheme was used to simulate a case of orographically enhanced ...

J. A. Milbrandt; M. K. Yau; J. Mailhot; S. Bélair

2008-10-01T23:59:59.000Z

479

Microphysical and Thermodynamic Structure and Evolution of the Trailing Stratiform Regions of Mesoscale Convective Systems during BAMEX. Part II: Column Model Simulations  

Science Conference Proceedings (OSTI)

This study employed a nondynamic microphysical column model to evaluate the degree to which the microphysical processes of sublimation, melting, and evaporation alone can explain the evolution of the relative humidity (RH) and latent cooling ...

Joseph A. Grim; Greg M. McFarquhar; Robert M. Rauber; Andrea M. Smith; Brian F. Jewett

2009-04-01T23:59:59.000Z

480

1  

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

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

Note: This page contains sample records for the topic "mixed-phase cloud microphysics" 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

Improvements of an Ice-Phase Microphysics Parameterization for Use in Numerical Simulations of Tropical Convection  

Science Conference Proceedings (OSTI)

It is important to properly simulate the extent and ice water content of tropical anvil clouds in numerical models that explicitly include cloud formation because of the significant effects that these clouds have on the radiation budget. For this ...

Steven K. Krueger; Qiang Fu; K. N. Liou; Hung-Neng S. Chin

1995-01-01T23:59:59.000Z

482

Evaluation of COAMPS Forecasts of Coastal Stratus Using Satellite Microphysical Retrievals and Aircraft Measurements  

Science Conference Proceedings (OSTI)

A field project was carried out offshore of central Oregon during August 1999 to evaluate mesoscale model simulations of coastal stratiform cloud layers. Procedures for mapping cloud physical parameters such as cloud optical depth, droplet ...

Melanie A. Wetzel; Steven K. Chai; Marcin J. Szumowski; William T. Thompson; Tracy Haack; Gabor Vali; Robert Kelly

2001-10-01T23:59:59.000Z

483

Snow studies, Part III-B: Ensemble retrieval of snow microphysics from dual wavelength vertically pointing radars  

Science Conference Proceedings (OSTI)

Based on the theory developed in Part III-A, this paper introduces a new method to retrieve snow microphysics from ground-based collocated X- and W-band vertically pointing Doppler radars. To take into account the variety of microphysical ...

Wanda Szyrmer; Isztar Zawadzki

484

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

SciTech Connect

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

Phillips, Vaughan T. J.

2013-10-18T23:59:59.000Z

485

A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS  

E-Print Network (OSTI)

Recent satellite data have revealed a surprising correlation between galactic cosmic ray (GCR) intensity and the fraction of the Earth covered by clouds. If this correlation were to be established by a causal mechanism, it could provide a crucial step in understanding the long-sought mechanism connecting solar and climate variability. The Earth's climate seems to be remarkably sensitive to solar activity, but variations of the Sun's electromagnetic radiation appear to be too small to account for the observed climate variability. However, since the GCR intensity is strongly modulated by the solar wind, a GCR-cloud link may provide a sufficient amplifying mechanism. Moreover if this connection were to be confirmed, it could have profound consequences for our understanding of the solar contributions to the current global warming. The CLOUD (Cosmics Leaving OUtdoor Droplets) project proposes to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. CLOUD plans to perform detailed laboratory measurements in a particle beam at CERN, where all the parameters can be precisely controlled and measured. The beam will pass through an expansion cloud chamber and a reactor chamber where the atmosphere is to be duplicated by moist air charged with selected aerosols and trace condensable vapours. An array of external detectors and mass spectrometers is used to analyse the physical and chemical characteristics of the aerosols and trace gases during beam exposure. Where beam effects are found, the experiment will seek to evaluate their significance in the atmosphere by incorporating them into aerosol and cloud models.

The Cloud Collaboration

2001-04-16T23:59:59.000Z

486

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

487

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

488

RACORO Extended-Term Aircraft Observations of Boundary-Layer Clouds  

SciTech Connect

A first-of-a-kind, extended-term cloud aircraft campaign was conducted to obtain an in-situ statistical characterization of boundary-layer clouds needed to investigate cloud processes and refine retrieval algorithms. Coordinated by the Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF), the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign operated over the ARM Southern Great Plains (SGP) site from 22 January to 30 June 2009, collecting 260 h of data during 59 research flights. A comprehensive payload aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft measured cloud microphysics, solar and thermal radiation, aerosol properties, and atmospheric state parameters. Proximity to the SGP's extensive complement of surface measurements provides ancillary data that supports modeling studies and enables evaluating a variety of surface retrieval algorithms. The five-month duration enabled sampling a range of conditions associated with the seasonal transition from winter to summer. Although about two-thirds of the cloud flights occurred in May and June, boundary-layer cloud fields were sampled under a variety of environmental and aerosol conditions, with about 75% of the flights occurring in cumulus and stratocumulus. Preliminary analyses show how these data are being used to analyze cloud-aerosol relationships, determine the aerosol sizes that are responsible for nucleating cloud drops, characterize the horizontal variability of the cloud radiative impacts, and evaluate air-borne and surface-based cloud property retrievals. We discuss how conducting an extended-term campaign requires a simplified operating paradigm that is different from that used for typical, short-term, intensive aircraft field programs.

Vogelmann, A. M.; McFarquhar, Greg; Ogren, John A.; Turner, David D.; Comstock, Jennifer M.; Feingold, G.; Long, Charles N.; Jonsson, Haf; Bucholtz, Anthony; Collins, Donald R.; Diskin, G. S.; Gerber, H.; Lawson, Paul; Woods, Roy; Andrews, Elizabeth; Yang, Hee-Jung; Chiu, Christine J.; Hartsock, Daniel; Hubbe, John M.; Lo, Chaomei; Marshak, A.; Monroe, Justin; McFarlane, Sally A.; Schmid, Beat; Tomlinson, Jason M.; Toto, Tami

2012-06-30T23:59:59.000Z

489

Global ice cloud observations: radiative properties and statistics from moderate-resolution imaging spectroradiometer measurements  

E-Print Network (OSTI)

Ice clouds occur quite frequently, yet so much about these clouds is unknown. In recent years, numerous investigations and field campaigns have been focused on the study of ice clouds, all with the ultimate goal of gaining a better understanding of microphysical and optical properties, as well as determining the radiative impact. Perhaps one of the most recognized instruments used for such research is the Moderate-resolution Imaging Spectroradiometer (MODIS), carried aboard the NASA EOS satellites Terra and Aqua. The present research aims to support ongoing efforts in the field of ice cloud research by use of observations obtained from Terra and Aqua MODIS. First, a technique is developed to infer ice cloud optical depth from the MODIS cirrus reflectance parameter. This technique is based on a previous method developed by Meyer et al. (2004). The applicability of the algorithm is demonstrated with retrieval