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Note: This page contains sample records for the topic "improving atmospheric models" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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1

Improving the performance scalability of the community atmosphere model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM), which serves as the atmosphere component of the Community Climate System Model (CCSM), is the most computationally expensive CCSM component in typical configurations. On current and next-generation leadership class ... Keywords: CAM, atmospheric modeling, massively parallel computing, performance, scalability

Arthur A. Mirin; Patrick H. Worley

2012-02-01T23:59:59.000Z

2

Recent Improvements to an Advanced Atmospheric Transport Modeling System  

SciTech Connect

The Atmospheric Technologies Group (ATG) has developed an advanced atmospheric modeling capability using the Regional Atmospheric Modeling System (RAMS) and a stochastic Lagrangian particle dispersion model (LPDM) for operational use at the Savannah River Site (SRS). For local simulations concerning releases from the Central Savannah River Area (CSRA), RAMS is run in a nested grid configuration with horizontal grid spacing of 8 and 2 km for each grid, with 6-hr forecasts updated every 3 hours. An interface to allow for easy user access to LPDM had been generated, complete with post-processing results depicting surface concentration, deposition, and a variety of dose quantities. A prior weakness in this approach was that observations from the SRS tower network were only incorporated into the three-dimensional modeling effort during the initialization process. Thus, if the forecasted wind fields were in error, the resulting plume predictions would also be erroneous. To overcome this shortcoming, the procedure for generating RAMS wind fields and reading them into LPDM has been modified such that SRS wind measurements are blended with the predicted three-dimensional wind fields from RAMS using the Barnes technique. In particular, the horizontal components in RAMS are replaced with the observed values at a series of 8 towers that exist within the SRS boundary (covering {approx}300 km{sup 2}). Even though LPDM is currently configured to account only for radioactive releases, it was used in a recent chlorine gas release to generate plume concentrations based on unit releases from the site of a train accident in Graniteville, South Carolina. This information was useful to local responders as an indication of potential protective actions downwind of the release.

Buckley, R. L.; Hunter, C. H.

2005-10-24T23:59:59.000Z

3

Improving the Ni I atomic model for solar and stellar atmospheric models  

E-Print Network (OSTI)

Neutral nickel (Ni I) is abundant in the solar atmosphere and is one of the important elements that contribute to the emission and absorption of radiation in the spectral range between 1900 and 3900 A. Previously, the Solar Radiation Physical Modeling (SRPM) models of the solar atmosphere considered only few levels of this species. Here we improve the Ni I atomic model by taking into account 61 levels and 490 spectral lines. We compute the populations of these levels in full NLTE using the SRPM code and compare the resulting emerging spectrum with observations. The present atomic model improves significantly the calculation of the solar spectral irradiance at near-UV wavelengths that are important for Earth atmo spheric studies, and particularly for ozone chemistry.

Vieytes, Mariela C

2013-01-01T23:59:59.000Z

4

Bootstrapping to Assess and Improve Atmospheric Prediction Models  

Science Conference Proceedings (OSTI)

Bootstrapping is a simple technique typically used to assess accuracy of estimates of model parameters by using simple plug-in principles and replacing sometimes unwieldy theory by computer simulation. Common uses include variance estimation and confidence ... Keywords: CART, bootstrap, classification, hurricanes, instability, supervised learning, weather data

J. Sunil Rao

2000-04-01T23:59:59.000Z

5

Volcanic forcing improves Atmosphere-Ocean Coupled General Circulation Model scaling performance  

E-Print Network (OSTI)

Recent Atmosphere-Ocean Coupled General Circulation Model (AOGCM) simulations of the twentieth century climate, which account for anthropogenic and natural forcings, make it possible to study the origin of long-term temperature correlations found in the observed records. We study ensemble experiments performed with the NCAR PCM for 10 different historical scenarios, including no forcings, greenhouse gas, sulfate aerosol, ozone, solar, volcanic forcing and various combinations, such as it natural, anthropogenic and all forcings. We compare the scaling exponents characterizing the long-term correlations of the observed and simulated model data for 16 representative land stations and 16 sites in the Atlantic Ocean for these scenarios. We find that inclusion of volcanic forcing in the AOGCM considerably improves the PCM scaling behavior. The scenarios containing volcanic forcing are able to reproduce quite well the observed scaling exponents for the land with exponents around 0.65 independent of the station dista...

Vyushin, D; Havlin, S; Bunde, A; Brenner, S; Vyushin, Dmitry; Zhidkov, Igor; Havlin, Shlomo; Bunde, Armin; Brenner, Stephen

2004-01-01T23:59:59.000Z

6

Improving the Detection and Tracking of Tropical Cyclones in Atmospheric General Circulation Models  

Science Conference Proceedings (OSTI)

Dynamical seasonal forecasts of tropical storm frequency require robust and efficient algorithms for detection and tracking of tropical storms in atmospheric general circulation models (AGCMs). Tropical storms are generally detected when dynamic ...

Suzana J. Camargo; Stephen E. Zebiak

2002-12-01T23:59:59.000Z

7

Improved Meteorological Input for Atmospheric Release Decision support Systems and an Integrated LES Modeling System for Atmospheric Dispersion of Toxic Agents: Homeland Security Applications  

SciTech Connect

When hazardous material is accidently or intentionally released into the atmosphere, emergency response organizations look to decision support systems (DSSs) to translate contaminant information provided by atmospheric models into effective decisions to protect the public and emergency responders and to mitigate subsequent consequences. The Department of Homeland Security (DHS)-led Interagency Modeling and Atmospheric Assessment Center (IMAAC) is one of the primary DSSs utilized by emergency management organizations. IMAAC is responsible for providing 'a single piont for the coordination and dissemination of Federal dispersion modeling and hazard prediction products that represent the Federal position' during actual or potential incidents under the National Response Plan. The Department of Energy's (DOE) National Atmospheric Release Advisory Center (NARAC), locatec at the Lawrence Livermore National Laboratory (LLNL), serves as the primary operations center of the IMAAC. A key component of atmospheric release decision support systems is meteorological information - models and data of winds, turbulence, and other atmospheric boundary-layer parameters. The accuracy of contaminant predictions is strongly dependent on the quality of this information. Therefore, the effectiveness of DSSs can be enhanced by improving the meteorological options available to drive atmospheric transport and fate models. The overall goal of this project was to develop and evaluate new meteorological modeling capabilities for DSSs based on the use of NASA Earth-science data sets in order to enhance the atmospheric-hazard information provided to emergency managers and responders. The final report describes the LLNL contributions to this multi-institutional effort. LLNL developed an approach to utilize NCAR meteorological predictions using NASA MODIS data for the New York City (NYC) region and demonstrated the potential impact of the use of different data sources and data parameterizations on IMAAC/NARAC fate and transport predictions. A case study involving coastal sea breeze circulation patterns in the NYC region was used to investigate the sensitivity of atmospheric dispersion results on the source of three-dimensional wind field data.

Arnold, E; Simpson, M; Larsen, S; Gash, J; Aluzzi, F; Lundquist, J; Sugiyama, G

2010-04-26T23:59:59.000Z

8

Improved representation of tropical Pacific ocean-atmosphere dynamics in an intermediate complexity climate model  

Science Conference Proceedings (OSTI)

A new anomaly coupling technique is introduced into a coarse-resolution dynamic climate model (LOVECLIM), improving the model’s representation of eastern equatorial Pacific surface temperature variability. The anomaly coupling amplifies the ...

Ryan L. Sriver; Axel Timmermann; Michael E. Mann; Klaus Keller; Hugues Goosse

9

Accelerating Progress in Global Atmospheric Model Development through Improved Parameterizations: Challenges, Opportunities, and Strategies  

Science Conference Proceedings (OSTI)

Meeting societal needs in weather, seasonal, and decadal prediction and climate projection requires a continuous improvement of the main tools used in making the predictions—global models of the Earth system. Despite significant progress in model ...

Christian Jakob

2010-07-01T23:59:59.000Z

10

Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model  

SciTech Connect

Highlight of Accomplishments: We made significant contribution to the ASR program in this funding cycle by better representing convective processes in GCMs based on knowledge gained from analysis of ARM/ASR observations. In addition, our work led to a much improved understanding of the interaction among aerosol, convection, clouds and climate in GCMs.

Zhang, Guang J [Scripps Institution of Oceanography

2013-07-29T23:59:59.000Z

11

An Improved Scheme for Interpolating between an Atmospheric Model and Underlying Surface Grids near Orography and Ocean Boundaries  

Science Conference Proceedings (OSTI)

To take into account the strong nonlinearities of vertical fluxes due to small-scale heterogeneities of surface properties, more and more coupled general circulation models compute part of their atmospheric physical parameterizations, either the ...

Francis Codron; Augustin Vintzileos; Robert Sadourny

2000-04-01T23:59:59.000Z

12

The Implementation and Validation of Improved Land-Surface Hydrology in an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

New land-surface hydrologic parameterizations are implemented into the NASA Goddard Institute for Space Studies (GISS) General Circulation Model (GCM). These parameterizations are: 1) runoff and evapotranspiration functions that include the ...

Kevin D. Johnson; Dara Entekhabi; Peter S. Eagleson

1993-06-01T23:59:59.000Z

13

Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model  

E-Print Network (OSTI)

Several regional-scale ecosystem models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, ...

Link, Percy Anne

2008-01-01T23:59:59.000Z

14

Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species  

Science Conference Proceedings (OSTI)

The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an associated surface correction for inventories that have counted emissions of CO2 precursors as CO2. We also explore the benefit of assimilating satellite observations of CO into GEOS-Chem to obtain an observation-based estimate of the CO2 chemical source. The CO assimilation corrects for an underestimate of atmospheric CO abundances in the model, resulting in increases of as much as 24% in the chemical source during May June 2006, and increasing the global annual estimate of CO2 chemical production from 1.05 to 1.18 Pg C. Comparisons of model CO2 with measurements are carried out in order to investigate the spatial and temporal distributions that result when these new sources are added. Inclusion of CO2 emissions from shipping and aviation are shown to increase the global CO2 latitudinal gradient by just over 0.10 ppm (3%), while the inclusion of CO2 chemical production (and the surface correction) is shown to decrease the latitudinal gradient by about 0.40 ppm (10%) with a complex spatial structure generally resulting in decreased CO2 over land and increased CO2 over the oceans. Since these CO2 emissions are omitted or misrepresented in most inverse modeling work to date, their implementation in forward simulations should lead to improved inverse modeling estimates of terrestrial biospheric fluxes.

Nassar, Ray [University of Toronto; Jones, DBA [University of Toronto; Suntharalingam, P [University of East Anglia, Norwich, United Kingdom; Chen, j. [University of Toronto; Andres, Robert Joseph [ORNL; Wecht, K. J. [Harvard University; Yantosca, R. M. [Harvard University; Kulawik, SS [Jet Propulsion Laboratory, Pasadena, CA; Bowman, K [Jet Propulsion Laboratory, Pasadena, CA; Worden, JR [Jet Propulsion Laboratory, Pasadena, CA; Machida, T [National Institute for Environmental Studies, Japan; Matsueda, H [Meteorological Research Institute, Japan

2010-01-01T23:59:59.000Z

15

Step-Mountain Technique Applied to an Atmospheric C-Grid Model, or How to Improve Precipitation near Mountains  

Science Conference Proceedings (OSTI)

Starting with Arakawa and Lamb’s second-order C-grid scheme, this paper describes the modifications made to the dynamics to create a C-grid atmospheric model with a variable number of cells for each vertical column. Where mountains exist, grid ...

Gary L. Russell

2007-12-01T23:59:59.000Z

16

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

17

Toward a Fully Lagrangian Atmospheric Modeling System  

Science Conference Proceedings (OSTI)

An improved treatment of advection is essential for atmospheric transport and chemistry models. Eulerian treatments are generally plagued with instabilities, unrealistic negative constituent values, diffusion, and dispersion errors. A higher-...

Jahrul M. Alam; John C. Lin

2008-12-01T23:59:59.000Z

18

Dynamic Stabilization of Atmospheric Single Column Models  

Science Conference Proceedings (OSTI)

Single column models (SCMs) provide an economical framework for assessing the sensitivity of atmospheric temperature and humidity to natural and imposed perturbations, and also for developing improved representations of diabatic processes in ...

John W. Bergman; Prashant D. Sardeshmukh

2004-03-01T23:59:59.000Z

19

Improved Seasonal Precipitation Forecasts for the Asian Monsoon Using 16 Atmosphere–Ocean Coupled Models. Part I: Climatology  

Science Conference Proceedings (OSTI)

The goal of this study is to utilize several recent developments on rainfall data collection, downscaling of available climate models, training and forecasts from such models within the framework of a multimodel superensemble, and first a detailed ...

Vinay Kumar; T. N. Krishnamurti

2012-01-01T23:59:59.000Z

20

Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands  

E-Print Network (OSTI)

for integrated field crop management. Cornell Universityactivity within the crop canopy. Aust. J. agric. Res. , 23,Assessing uncertainties in crop model simulations using

Lokupitiya, Erandathie

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Simple Modifications to Improve Fifth-Generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model Performance for the Phoenix, Arizona, Metropolitan Area  

Science Conference Proceedings (OSTI)

The diurnal temperature cycle in the Phoenix, Arizona, metropolitan area, as represented in the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5), is examined using a high-resolution 2-...

Joseph A. Zehnder

2002-09-01T23:59:59.000Z

22

Improved Middle Atmosphere Climate and Forecasts in the ECMWF Model through a Nonorographic Gravity Wave Drag Parameterization  

Science Conference Proceedings (OSTI)

In model cycle 35r3 (Cy35r3) of the ECMWF Integrated Forecast System (IFS), the momentum deposition from small-scale nonorographic gravity waves is parameterized by the Scinocca scheme, which uses hydrostatic nonrotational wave dynamics to ...

Andrew Orr; Peter Bechtold; John Scinocca; Manfred Ern; Marta Janiskova

2010-11-01T23:59:59.000Z

23

Improved Seasonal Climate Forecasts of the South Asian Summer Monsoon Using a Suite of 13 Coupled Ocean–Atmosphere Models  

Science Conference Proceedings (OSTI)

Several modeling studies have shown that the south Asian monsoon region has the lowest skill for seasonal forecasts compared with many other domains of the world. This paper demonstrates that a multimodel synthetic superensemble approach, when ...

Arindam Chakraborty; T. N. Krishnamurti

2006-06-01T23:59:59.000Z

24

Quality Assurance in Atmospheric Modeling  

Science Conference Proceedings (OSTI)

This paper summarizes a number of best practices associated with the use of numerical models of the atmosphere and is motivated by the rapid growth in the number of model users, who have a range of scientific and technical preparations. An underlying ...

Thomas T. Warner

2011-12-01T23:59:59.000Z

25

A Community Atmosphere Model with Superparameterized Clouds  

SciTech Connect

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

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

2013-06-18T23:59:59.000Z

26

Testing and Evaluating Atmospheric Climate Models  

Science Conference Proceedings (OSTI)

Model validation is a crucial process that underpins model development and gives confidence to the results from running models. This article discusses a range of techniques for validating atmosphere models given that the atmosphere is chaotic and incompletely ...

Vicky Pope; Terry Davies

2002-09-01T23:59:59.000Z

27

Empirical Correction of a Coupled Land–Atmosphere Model  

Science Conference Proceedings (OSTI)

This paper investigates empirical strategies for correcting the bias of a coupled land–atmosphere model and tests the hypothesis that a bias correction can improve the skill of such models. The correction strategies investigated include 1) ...

Timothy DelSole; Mei Zhao; Paul A. Dirmeyer; Ben P. Kirtman

2008-11-01T23:59:59.000Z

28

AMIP: The Atmospheric Model Intercomparison Project  

Science Conference Proceedings (OSTI)

The Atmospheric Model Intercomparison Project (AMIP) is an international effort to determine the systematic climate errors of atmospheric models under realistic conditions, and calls for the simulation of the climate of the decade 1979–1988 using ...

W. Lawrence Gates

1992-12-01T23:59:59.000Z

29

VALDRIFT—A Valley Atmospheric Dispersion Model  

Science Conference Proceedings (OSTI)

VALDRIFT (valley drift) is a valley atmospheric transport, diffusion, and deposition model. The model is phenomenological—that is, the dominant meteorological processes governing the behavior of the valley atmosphere are formulated explicitly in ...

K. Jerry Allwine; Xindi Bian; C. David Whiteman; Harold W. Thistle

1997-08-01T23:59:59.000Z

30

A New Moist Turbulence Parameterization in the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

A new moist turbulence parameterization is presented and implemented in the Community Atmosphere Model (CAM). It is derived from Grenier and Bretherton but has been heavily modified to improve its numerical stability and efficiency with the long ...

Christopher S. Bretherton; Sungsu Park

2009-06-01T23:59:59.000Z

31

FOAM:The Fast Ocean Atmosphere Model  

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

Models Performance User Resources Publications History Developer's Page FOAM The Fast Ocean Atmosphere Model cup2.jpeg (48474 bytes) Image made by Johan Kellum with Vis5D...

32

Advanced Atmospheric Modeling for Emergency Response  

Science Conference Proceedings (OSTI)

Atmospheric transport and diffusion models are an important part of emergency response systems for industrial facilities that have the potential to release significant quantities of toxic or radioactive material into the atmosphere. An advanced ...

Jerome D. Fast; B. Lance O'steen; Robert P. Addis

1995-03-01T23:59:59.000Z

33

Coupled Atmosphere–Biophysics–Hydrology Models for Environmental Modeling  

Science Conference Proceedings (OSTI)

The formulation and implementation of LEAF-2, the Land Ecosystem–Atmosphere Feedback model, which comprises the representation of land–surface processes in the Regional Atmospheric Modeling System (RAMS), is described. LEAF-2 is a prognostic ...

Robert L. Walko; Larry E. Band; Jill Baron; Timothy G. F. Kittel; Richard Lammers; Tsengdar J. Lee; Dennis Ojima; Roger A. Pielke Sr.; Chris Taylor; Christina Tague; Craig J. Tremback; Pier Luigi Vidale

2000-06-01T23:59:59.000Z

34

I. Atmosphere Model Working Group (AMWG)  

E-Print Network (OSTI)

The AMWG used its development allocation for three main purposes: to understand, diagnose, and document the behavior of the Community Atmosphere Model (CAM3); to continue the evolution of the model beyond CAM3, including debugging and software engineering; and to understand and document aspects of the new functionality of the model. Substantial software engineering changes were made to CAM to more effectively isolate the points of interaction between model components and the rest of the CAM infrastructure. More components have an Earth System Modeling Framework (ESMF) type structure of "Initialize", "Run " and "Finalize, " which moves the model toward ESMF compatibility. We also made a number of changes to the model to facilitate the inclusion of other dynamical cores, particularly cores that will allow CAM to use model grids that are not oriented by latitude and longitude (e.g., cubed sphere and icosahedral/ triangular meshes). Extra software engineering features were also added, including Single Program-Multiple Data (SPMD) optimizations and extensions for CRAY and NEC platforms, changes to support IA64 clusters, and a number of bug fixes to improve

unknown authors

2004-01-01T23:59:59.000Z

35

Filtering of Gravity Modes in Atmospheric Models  

Science Conference Proceedings (OSTI)

The impact of gravity modes in atmospheric model predictions is assessed quantitatively by comparing integrations with a normal mode initialized primitive equation model and its corresponding pseudogeostrophic form to document some generally ...

F. Baer; J. J. Tribbia

1984-05-01T23:59:59.000Z

36

A GRID OF THREE-DIMENSIONAL STELLAR ATMOSPHERE MODELS OF SOLAR METALLICITY. I. GENERAL PROPERTIES, GRANULATION, AND ATMOSPHERIC EXPANSION  

SciTech Connect

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive power to such models of late-type stars. We present a grid of improved and more reliable stellar atmosphere models of late-type stars, based on deep, three-dimensional (3D), convective, stellar atmosphere simulations. This grid is to be used in general for interpreting observations and improving stellar and asteroseismic modeling. We solve the Navier Stokes equations in 3D and concurrent with the radiative transfer equation, for a range of atmospheric parameters, covering most of stellar evolution with convection at the surface. We emphasize the use of the best available atomic physics for quantitative predictions and comparisons with observations. We present granulation size, convective expansion of the acoustic cavity, and asymptotic adiabat as functions of atmospheric parameters.

Trampedach, Regner [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States); Asplund, Martin; Collet, Remo [Research School of Astronomy and Astrophysics, Mt. Stromlo Observatory, Cotter Road, Weston ACT 2611 (Australia); Nordlund, Ake [Astronomical Observatory/Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Stein, Robert F. [Department of Physics and Astronomy, Michigan State University East Lansing, MI 48824 (United States)

2013-05-20T23:59:59.000Z

37

Improved steamflood analytical model  

E-Print Network (OSTI)

The Jeff Jones steamflood model incorporates oil displacement by steam as described by Myhill and Stegemeier, and a three-component capture factor based on empirical correlations. The main drawback of the model however is the unsatisfactory prediction of the oil production peak: usually significantly lower than the actual. Our study focuses on improving this aspect of the Jeff Jones model. In our study, we simulated the production performance of a 5-spot steamflood pattern unit and compared the results against those based on the Jeff Jones model. Three reservoir types were simulated using 3-D Cartesian black oil models: Hamaca (9�°API), San Ardo (12�°API) and that based on the SPE fourth comparative solution project (14�°API). In the first two field cases, a 45x23x8 model was used that represented 1/8 of a 10-acre 5-spot pattern unit, using typical rock and reservoir fluid properties. In the SPE project case, three models were used: 23x12x12 (2.5 ac), 31x16x12 (5 ac) and 45x23x8 (10 ac), that represented 1/8 of a 5-spot pattern unit. To obtain a satisfactory match between simulation and Jeff Jones analytical model results of the start and height of the production peak, the following refinements to the Jeff Jones model were necessary. First, the dimensionless steam zone size AcD was modified to account for decrease in oil viscosity during steamflood and its dependence on the steam injection rate. Second, the dimensionless volume of displaced oil produced VoD was modified from its square-root format to an exponential form. The modified model gave very satisfactory results for production performance up to 20 years of simulated steamflood, compared to the original Jeff Jones model. Engineers will find the modified model an improved and useful tool for prediction of steamflood production performance.

Chandra, Suandy

2005-08-01T23:59:59.000Z

38

Spectral Preconditioners for Nonhydrostatic Atmospheric Models  

Science Conference Proceedings (OSTI)

The elliptic problems in semi-implicit nonhydrostatic atmospheric models are difficult. Typically, they are poorly conditioned, nonseparable, contain cross-derivative terms, and are often nonsymmetric. Here, the resulting linear system is solved ...

Stephen J. Thomas; Joshua P. Hacker; Piotr K. Smolarkiewicz; Roland B. Stull

2003-10-01T23:59:59.000Z

39

Intraseasonal Variability in a Dry Atmospheric Model  

Science Conference Proceedings (OSTI)

A long integration of a primitive equation dry atmospheric model with time-independent forcing under boreal winter conditions is analyzed. A variety of techniques such as time filtering, space–time spectral analysis, and lag regressions are used ...

Hai Lin; Gilbert Brunet; Jacques Derome

2007-07-01T23:59:59.000Z

40

The Atmospheric Mesoscale Dispersion Modeling System  

Science Conference Proceedings (OSTI)

The mesoscale dispersion modeling system (MDMS) described herein is under development as a simulation tool to investigate atmospheric flow and pollution dispersion over complex terrain for domains up to several hundred kilometers. The system ...

Marek Uliasz

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

State-Space Modeling for Atmospheric Pollution  

Science Conference Proceedings (OSTI)

Two different aspect concerning the state-space modeling for atmospheric pollution are dealt with separately in this paper: (i) the treatment of the advection-diffusion equation and (ii) the use of time series analysis.

E. Hernández; F. Martín; F. Valero

1991-06-01T23:59:59.000Z

42

Vacillations in a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

Results are presented from a 35-year integration of a coupled ocean-atmosphere model. Both ocean and atmosphere are two-level, nonlinear primitive equations models. The global atmospheric model is forced by a steady, zonally symmetric Newtonian ...

Paul S. Schopf; Max J. Suarez

1988-02-01T23:59:59.000Z

43

The Mathematics of Atmospheric Dispersion Modeling  

Science Conference Proceedings (OSTI)

The Gaussian plume model is a standard approach for studying the transport of airborne contaminants due to turbulent diffusion and advection by the wind. This paper reviews the assumptions underlying the model, its derivation from the advection-diffusion ... Keywords: Gaussian plume solution, advection-diffusion equation, atmospheric dispersion, contaminant transport, inverse problem, linear least squares

John M. Stockie

2011-05-01T23:59:59.000Z

44

Improved MK42 Melting Model  

Science Conference Proceedings (OSTI)

An improved Mark 42 melting model has been defined for establishing confinement protection limits (CPLs). This report describes the new melting model and its application in computing CPLs.

Tudor, A.A.

2001-09-19T23:59:59.000Z

45

A Revised Land Surface Parameterization (SiB2) for Atmospheric GCMS. Part I: Model Formulation  

Science Conference Proceedings (OSTI)

The formulation of a revised land surface parameterization for use within atmospheric general circulation models (GCMs) is presented. The model (SiB2) incorporates several significant improvements over the first version of the Simple Biosphere ...

P.J. Sellers; D.A. Randall; G.J. Collatz; J.A. Berry; C.B. Field; D.A. Dazlich; C. Zhang; G.D. Collelo; L. Bounoua

1996-04-01T23:59:59.000Z

46

Constraining the Influence of Natural Variability to Improve Estimates of Global Aerosol Indirect Effects in a Nudged Version of the Community Atmosphere Model 5  

SciTech Connect

Natural modes of variability on many timescales influence aerosol particle distributions and cloud properties such that isolating statistically significant differences in cloud radiative forcing due to anthropogenic aerosol perturbations (indirect effects) typically requires integrating over long simulations. For state-of-the-art global climate models (GCM), especially those in which embedded cloud-resolving models replace conventional statistical parameterizations (i.e. multi-scale modeling framework, MMF), the required long integrations can be prohibitively expensive. Here an alternative approach is explored, which implements Newtonian relaxation (nudging) to constrain simulations with both pre-industrial and present-day aerosol emissions toward identical meteorological conditions, thus reducing differences in natural variability and dampening feedback responses in order to isolate radiative forcing. Ten-year GCM simulations with nudging provide a more stable estimate of the global-annual mean aerosol indirect radiative forcing than do conventional free-running simulations. The estimates have mean values and 95% confidence intervals of -1.54 ± 0.02 W/m2 and -1.63 ± 0.17 W/m2 for nudged and free-running simulations, respectively. Nudging also substantially increases the fraction of the world’s area in which a statistically significant aerosol indirect effect can be detected (68% and 25% of the Earth's surface for nudged and free-running simulations, respectively). One-year MMF simulations with and without nudging provide global-annual mean aerosol indirect radiative forcing estimates of -0.80 W/m2 and -0.56 W/m2, respectively. The one-year nudged results compare well with previous estimates from three-year free-running simulations (-0.77 W/m2), which showed the aerosol-cloud relationship to be in better agreement with observations and high-resolution models than in the results obtained with conventional parameterizations.

Kooperman, G. J.; Pritchard, M. S.; Ghan, Steven J.; Wang, Minghuai; Somerville, Richard C.; Russell, Lynn

2012-12-11T23:59:59.000Z

47

Atmospheric Dispersion Modeling in Safety Analyses; GENII  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Workshop to Discuss Issues Regarding Deposition Workshop to Discuss Issues Regarding Deposition Velocity June 5-6, 2012 Jeremy Rishel Bruce Napier Atmospheric Dispersion Modeling in Safety Analyses: GENII Today's Presentation.... Will provide a high-level overview of the GENII codes. Will cover basic aspects of GENII's acute atmospheric transport model. Will review the GENII deposition model that is used to estimate the deposition velocity used in plume depletion. 2 GENII Development History 1988 - GENII V1 released ICRP-26/30/48 dosimetry 1990 - GENII V1.485 stabilized Current DOE Toolbox Version 1992 - GENII-S stochastic version 2004 - GENII V2 ICRP-72 age-dependent dosimetry Federal Guidance Report 13 risk factors

48

3D atmospheric modeling based on MODTRAN4  

Science Conference Proceedings (OSTI)

All the factors of atmospheric environment that influence the transmission of infrared radiation were analyzed in detail in the paper. Taking horizontally varying atmospheric property into consideration, a 3D model of atmospheric transmission of infrared ... Keywords: MODTRAN4, infrared radiation, model, path radiation, ratio of atmospheric transmission, simulation, single scatter solar radiation

Ge Li; Zhifeng Lu; Gang Guo; Kedi Huang

2008-06-01T23:59:59.000Z

49

Baiu rainband termination in atmospheric and atmosphere-ocean models  

Science Conference Proceedings (OSTI)

Baiu rainband is a summer rainband stretching from eastern China through Japan towards the Northwest Pacific. The climatological termination of the Baiu rainband is investigated using Japanese 25-year ReAnalysis (JRA25), a stand-alone atmospheric ...

Akira Kuwano-Yoshida; Bunmei Taguchi; Shang-Ping Xie

50

Transient Response of a Global Ocean-Atmosphere Model to a Doubling of Atmospheric Carbon Dioxide  

Science Conference Proceedings (OSTI)

The transient response of climate to an instantaneous increase in the atmospheric concentration of carbon dioxide has been investigated by a general circulation model of the coupled ocean-atmosphere-land system with global geography and annual ...

Syukuro Manabe; Kirk Bryan; Michael J. Spelman

1990-05-01T23:59:59.000Z

51

Response of the Middle Atmosphere to CO2 Doubling: Results from the Canadian Middle Atmosphere Model  

Science Conference Proceedings (OSTI)

The Canadian Middle Atmosphere Model (CMAM) has been used to examine the middle atmosphere response to CO2 doubling. The radiative-photochemical response induced by doubling CO2 alone and the response produced by changes in prescribed SSTs are ...

V. I. Fomichev; A. I. Jonsson; J. de Grandpré; S. R. Beagley; C. McLandress; K. Semeniuk; T. G. Shepherd

2007-04-01T23:59:59.000Z

52

A Thermodynamic Foundation for Modeling the Moist Atmosphere  

Science Conference Proceedings (OSTI)

With advances in numerical modeling of the atmosphere, we have experienced that the return to the first principles of physics often enables a model to cope more easily with the complexities of the real atmosphere. The return to the primitive ...

Katsuyuki V. Ooyama

1990-11-01T23:59:59.000Z

53

How realistic are solar model atmospheres?  

E-Print Network (OSTI)

Recently, new solar model atmospheres have been developed to replace classical 1D LTE hydrostatic models and used to for example derive the solar chemical composition. We aim to test various models against key observational constraints. In particular, a 3D model used to derive the solar abundances, a 3D MHD model (with an imposed 10 mT vertical magnetic field), 1D models from the PHOENIX project, the 1D MARCS model, and the 1D semi-empirical model of Holweger & M\\"uller. We confront the models with observational diagnostics of the temperature profile: continuum centre-to-limb variations (CLV), absolute continuum fluxes, and the wings of hydrogen lines. We also test the 3D models for the intensity distribution of the granulation and spectral line shapes. The predictions from the 3D model are in excellent agreement with the continuum CLV observations, performing even better than the Holweger & M\\"uller model (constructed largely to fulfil such observations). The predictions of the 1D theoretical models ...

Pereira, Tiago M D; Collet, Remo; Thaler, Irina; Trampedach, Regner; Leenaarts, Jorrit

2013-01-01T23:59:59.000Z

54

Development of a 3D atmospheric radiative transfer model  

Science Conference Proceedings (OSTI)

The 3D atmospheric radiative transfer model is established based on MODTRAN4. Moreover, the methods of calculating the ratio of atmospheric transmission, path radiation and single scattering solar radiation are presented. This 3D model is running by ... Keywords: MODTRAN4, atmospheric radiative transfer model, infrared radiation

Zhifeng Lu; Ge Li; Gang Guo; Kedi Huang

2008-05-01T23:59:59.000Z

55

Flux Replacement as a Method to Diagnose Coupled Land–Atmosphere Model Feedback  

Science Conference Proceedings (OSTI)

The potential role of the land surface state in improving predictions of seasonal climate is investigated with a coupled land–atmosphere climate model. Climate simulations for 18 boreal-summer seasons (1982–99) have been conducted with specified ...

Paul A. Dirmeyer; Mei Zhao

2004-12-01T23:59:59.000Z

56

Impact of Ingesting Satellite-Derived Cloud Cover into the Regional Atmospheric Modeling System  

Science Conference Proceedings (OSTI)

This study investigates the extent to which assimilating high-resolution remotely sensed cloud cover into the Regional Atmospheric Modeling System (RAMS) provides an improved regional diagnosis of downward short- and longwave surface radiation ...

Ismail Yucel; W. James Shuttleworth; R. T. Pinker; L. Lu; S. Sorooshian

2002-03-01T23:59:59.000Z

57

Representing Grass– and Shrub–Snow–Atmosphere Interactions in Climate System Models  

Science Conference Proceedings (OSTI)

A vegetation-protruding-above-snow parameterization for earth system models was developed to improve energy budget calculations of interactions among vegetation, snow, and the atmosphere in nonforested areas. These areas include shrublands, ...

Glen E. Liston; Christopher A. Hiemstra

2011-04-01T23:59:59.000Z

58

Visualizing Storms from NCAR's Atmosphere Model at NERSC  

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

Community Atmosphere Model, we are studying how well the model can reproduced observed tropical cyclone statistics. The simulated storms seen in this animation are generated...

59

Adaptive Multilevel Modeling of Land-Atmosphere Interactions  

Science Conference Proceedings (OSTI)

Adaptive multilevel methods allow full coupling of atmospheric and land surface hydrological models by preserving consistency between the large-scale (atmospheric) and the regional (land) components. The methodology was investigated for three ...

Ana Paula Barros

1995-09-01T23:59:59.000Z

60

Predictability Associated with Nonlinear Regimes in an Atmospheric Model  

Science Conference Proceedings (OSTI)

Atmospheric regimes are midlatitude flow patterns that persist for periods of time exceeding a few days. Here, the authors analyzed the output of an idealized atmospheric model (QG3) to examine the relationship between regimes and predictability.

John M. Peters; Sergey Kravtsov; Nicholas T. Schwartz

2012-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Nonhydrostatic icosahedral atmospheric model (NICAM) for global cloud resolving simulations  

Science Conference Proceedings (OSTI)

A new type of ultra-high resolution atmospheric global circulation model is developed. The new model is designed to perform ''cloud resolving simulations'' by directly calculating deep convection and meso-scale circulations, which play key roles not ... Keywords: Aqua-planet experiments, Atmospheric general circulation models, Cloud clusters, Cloud resolving model, Icosahedral grids, Nonhydrostatic model

M. Satoh; T. Matsuno; H. Tomita; H. Miura; T. Nasuno; S. Iga

2008-03-01T23:59:59.000Z

62

Regional forecasting with global atmospheric models; Final report  

SciTech Connect

The purpose of the project was to conduct model simulations for past and future climate change with respect to the proposed Yucca Mtn. repository. The authors report on three main topics, one of which is boundary conditions for paleo-hindcast studies. These conditions are necessary for the conduction of three to four model simulations. The boundary conditions have been prepared for future runs. The second topic is (a) comparing the atmospheric general circulation model (GCM) with observations and other GCMs; and (b) development of a better precipitation data base for the Yucca Mtn. region for comparisons with models. These tasks have been completed. The third topic is preliminary assessments of future climate change. Energy balance model (EBM) simulations suggest that the greenhouse effect will likely dominate climate change at Yucca Mtn. for the next 10,000 years. The EBM study should improve rational choice of GCM CO{sub 2} scenarios for future climate change.

Crowley, T.J.; Smith, N.R. [Applied Research Corp., College Station, TX (United States)

1994-05-01T23:59:59.000Z

63

Improvement Of The Wind Farm Model Flap For Offshore Applications  

E-Print Network (OSTI)

The wind farm program FLaP (Farm Layout Program), developed at the University of Oldenburg, has been extended to improve the description of wake development in offshore conditions, especially the low ambient turbulence and the effect of atmospheric stability. Model results have been compared with measurements from the Danish offshore wind farm Vindeby. Vertical wake profiles and mean turbulence intensities in the wake were compared for 32 scenarios of single, double and quintuple wake cases with different mean wind speed, turbulence intensity and atmospheric stability. It was found that within the measurement uncertainties the results of the wake model compares well with the measurements for the most important ambient conditions. The effect of the low turbulence intensity offshore on the wake development was modelled well. Deviations have been found when atmospheric stability deviates from near-neutral conditions. Especially for stable atmospheric conditions both the free flow model and the wake model do not give satisfying results.

Bernhard Lange; Hans-peter Waldl; Rebecca Barthelmie; Algert Gil Guerrero; Detlev Heinemann

2002-01-01T23:59:59.000Z

64

Discrete Packet Analysis for Improved Atmospheric Rejection on Modulated Laser Signals  

SciTech Connect

This slide-show discusses how the method of discrete packet analysis improves atmospheric compensation for quasi-CW fluorescence detection methods. This is key to improving remote sensing capabilities.

O'Neill, M., McKenna, I., DiBenedetto, J., Capelle, G., Trainham, R.

2012-07-19T23:59:59.000Z

65

An Improved Parameterization for Estimating Effective Atmospheric Emissivity for Use in Calculating Daytime Downwelling Longwave Radiation  

Science Conference Proceedings (OSTI)

An improved parameterization is presented for estimating effective atmospheric emissivity for use in calculating downwelling longwave radiation based on temperature, humidity, pressure, and solar radiation observations. The first improvement is ...

Todd M. Crawford; Claude E. Duchon

1999-04-01T23:59:59.000Z

66

The Limitations of CFD Modeling for Furnace Atmosphere ... - TMS  

Science Conference Proceedings (OSTI)

Feb 1, 2002 ... The Limitations of CFD Modeling for Furnace Atmosphere Troubleshooting by P.F. Stratton, N. Saxena and M. Huggahalli ...

67

Efficient Parallel I/O in Community Atmosphere Model (CAM)  

Science Conference Proceedings (OSTI)

Century-long global climate simulations at high resolutions generate large amounts of data in a parallel architecture. Currently, the community atmosphere model (CAM), the atmospheric component of the NCAR community climate system model (CCSM), uses ... Keywords: CAM, climate modeling, index reshuffle, parallel I/O, parallel netCDF

Yu-Heng Tseng; Chris Ding

2008-05-01T23:59:59.000Z

68

Circulation Regimes due to Attractor Merging in Atmospheric Models  

Science Conference Proceedings (OSTI)

From a dynamical systems theory perspective, the mechanisms of atmospheric regime behavior in a barotropic model, a pseudobarotropic model, and a baroclinic three-level model, where all of them show quite realistic regimes, are unveiled. Along ...

Mario Sempf; Klaus Dethloff; Dörthe Handorf; Michael V. Kurgansky

2007-06-01T23:59:59.000Z

69

Uncertainties in (E)UV model atmosphere fluxes (Research Note)  

E-Print Network (OSTI)

Context. During the comparison of synthetic spectra calculated with two NLTE model atmosphere codes, namely TMAP and TLUSTY, we encounter systematic differences in the EUV fluxes due to the treatment of level dissolution by pressure ionization. Aims. In the case of Sirius B, we demonstrate an uncertainty in modeling the EUV flux reliably in order to challenge theoreticians to improve the theory of level dissolution. Methods. We calculated synthetic spectra for hot, compact stars using state-of-the-art NLTE model-atmosphere techniques. Results. Systematic differences may occur due to a code-specific cutoff frequency of the H I Lyman bound-free opacity. This is the case for TMAP and TLUSTY. Both codes predict the same flux level at wavelengths lower than about 1500 Å for stars with effective temperatures (Teff) below about 30 000 K only, if the same cutoff frequency is chosen. Conclusions. The theory of level dissolution in high-density plasmas, which is available for hydrogen only should be generalized to all species. Especially, the cutoff frequencies for the bound-free opacities should be defined in order to make predictions of UV fluxes more reliable.

T. Rauch

2008-01-01T23:59:59.000Z

70

Laboratory measurements and modeling of trace atmospheric species  

E-Print Network (OSTI)

Trace species play a major role in many physical and chemical processes in the atmosphere. Improving our understanding of the impact of each species requires a combination of laboratory exper- imentation, field measurements, ...

Sheehy, Philip M. (Philip Michael)

2005-01-01T23:59:59.000Z

71

Application of Improved Radiation Modeling to General Circulation Models  

SciTech Connect

This research has accomplished its primary objectives of developing accurate and efficient radiation codes, validating them with measurements and higher resolution models, and providing these advancements to the global modeling community to enhance the treatment of cloud and radiative processes in weather and climate prediction models. A critical component of this research has been the development of the longwave and shortwave broadband radiative transfer code for general circulation model (GCM) applications, RRTMG, which is based on the single-column reference code, RRTM, also developed at AER. RRTMG is a rigorously tested radiation model that retains a considerable level of accuracy relative to higher resolution models and measurements despite the performance enhancements that have made it possible to apply this radiation code successfully to global dynamical models. This model includes the radiative effects of all significant atmospheric gases, and it treats the absorption and scattering from liquid and ice clouds and aerosols. RRTMG also includes a statistical technique for representing small-scale cloud variability, such as cloud fraction and the vertical overlap of clouds, which has been shown to improve cloud radiative forcing in global models. This development approach has provided a direct link from observations to the enhanced radiative transfer provided by RRTMG for application to GCMs. Recent comparison of existing climate model radiation codes with high resolution models has documented the improved radiative forcing capability provided by RRTMG, especially at the surface, relative to other GCM radiation models. Due to its high accuracy, its connection to observations, and its computational efficiency, RRTMG has been implemented operationally in many national and international dynamical models to provide validated radiative transfer for improving weather forecasts and enhancing the prediction of global climate change.

Michael J Iacono

2011-04-07T23:59:59.000Z

72

Development of a Coupled Groundwater–Atmosphere Model  

Science Conference Proceedings (OSTI)

Complete models of the hydrologic cycle have gained recent attention as research has shown interdependence between the coupled land and energy balance of the subsurface, land surface, and lower atmosphere. PF.WRF is a new model that is a ...

Reed M. Maxwell; Julie K. Lundquist; Jeffrey D. Mirocha; Steven G. Smith; Carol S. Woodward; Andrew F. B. Tompson

2011-01-01T23:59:59.000Z

73

Ocean Eddy Dynamics in a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The role of mesoscale oceanic eddies is analyzed in a quasigeostrophic coupled ocean–atmosphere model operating at a large Reynolds number. The model dynamics are characterized by decadal variability that involves nonlinear adjustment of the ...

P. Berloff; W. Dewar; S. Kravtsov; J. McWilliams

2007-05-01T23:59:59.000Z

74

An Eulerian Limited-Area Atmospheric Transport Model  

Science Conference Proceedings (OSTI)

A limited-area, offline, Eulerian atmospheric transport model has been developed. The model is based on a terrain-following vertical coordinate and a mass-conserving, positive definite advection scheme with small phase and amplitude errors. The ...

Lennart Robertson; Joakim Langner; Magnuz Engardt

1999-02-01T23:59:59.000Z

75

Evaluating Error Propagation in Coupled Land–Atmosphere Models  

Science Conference Proceedings (OSTI)

This study examines how land-use errors from the Land Transformation Model (LTM) propagate through to climate as simulated by the Regional Atmospheric Model System (RAMS). The authors conducted five simulations of regional climate over East Africa:...

Bryan Pijanowski; Nathan Moore; Dasaraden Mauree; Dev Niyogi

2011-10-01T23:59:59.000Z

76

Atmosphere–Ocean Modeling Exploiting Fluid Isomorphisms  

Science Conference Proceedings (OSTI)

Mathematical isomorphisms between the hydrostatic equations that govern the evolution of a compressible atmosphere and an incompressible ocean are described and exploited to guide the design of a hydrodynamical kernel for simulation of either ...

John Marshall; Alistair Adcroft; Jean-Michel Campin; Chris Hill; Andy White

2004-12-01T23:59:59.000Z

77

Reduction of Middle-Atmospheric Forecast Bias through Improvement in Satellite Radiance Quality Control  

Science Conference Proceedings (OSTI)

This article discusses a practical problem faced in operational atmospheric forecasting and data assimilation, and efforts to improve forecast quality through the choice of quality control parameters. The need to utilize as much data as possible ...

Young-Joon Kim; William F. Campbell; Steven D. Swadley

2010-04-01T23:59:59.000Z

78

Modeling the effects of atmospheric emissions on groundwater composition  

SciTech Connect

A composite model of atmospheric, unsaturated and groundwater transport is developed to evaluate the processes determining the distribution of atmospherically derived contaminants in groundwater systems and to test the sensitivity of simulated contaminant concentrations to input parameters and model linkages. One application is to screen specific atmospheric emissions for their potential in determining groundwater age. Temporal changes in atmospheric emissions could provide a recognizable pattern in the groundwater system. The model also provides a way for quantifying the significance of uncertainties in the tracer source term and transport parameters on the contaminant distribution in the groundwater system, an essential step in using the distribution of contaminants from local, point source atmospheric emissions to examine conceptual models of groundwater flow and transport.

Brown, T.J.

1994-12-31T23:59:59.000Z

79

FOAM: Fast Ocean Atmosphere Model | Argonne National Laboratory  

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

FOAM: Fast Ocean Atmosphere Model FOAM: Fast Ocean Atmosphere Model FOAM: Fast Ocean Atmosphere Model FOAM is a fully coupled, mixed-resolution, general circulation model designed for high-throughput (simulated years per day) while still providing a good simulated mean climate and simulated variability. FOAM uses the combination of a low resolution (R15) atmosphere model, a highly efficient medium-resolution ocean model, and distributed memory parallel processing to achieve high throughput on relatively modest numbers of processors (16-64). The quality of the simulated climate compares well with higher resolution models. No flux corrections are used. FOAM's intended purpose is to study long-term natural variability in the climate system. FOAM is also well suited for paleoclimate applications. FOAM is highly

80

Can a Regional Climate Model Improve the Ability to Forecast the North American Monsoon?  

Science Conference Proceedings (OSTI)

Global climate models are challenged to represent the North American monsoon, in terms of its climatology and interannual variability. To investigate whether a regional atmospheric model can improve warm season forecasts in North America, a ...

Christopher L. Castro; Hsin-I Chang; Francina Dominguez; Carlos Carrillo; Jae-Kyung Schemm; Hann-Ming Henry Juang

2012-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

A Seasonally Forced Ocean–Atmosphere Model for Paleoclimate Studies  

Science Conference Proceedings (OSTI)

Seasonal forcing is applied to an idealized model of the ocean–atmosphere system by prescribing monthly values of solar insolation at the top of the atmosphere and wind stress at the ocean surface. In addition, meridional near-surface wind ...

Andreas Schmittner; Thomas F. Stocker

2001-03-01T23:59:59.000Z

82

Improving Spectral Models By Unfolding Their Singularities  

Science Conference Proceedings (OSTI)

Maximally truncated spectral models have been used recently by fluid and atmospheric dynamicists to study nonlinear behavior of the governing partial differential system. However, too few external control parameters may be available in the ...

Hampton N. Shirer; Robert Wells

1982-03-01T23:59:59.000Z

83

Revisiting the Carrington Event: Updated modeling of atmospheric effects  

E-Print Network (OSTI)

The terrestrial effects of major solar events such as the Carrington white-light flare and subsequent geomagnetic storm of August-September 1859 are of considerable interest, especially in light of recent predictions that such extreme events will be more likely over the coming decades. Here we present results of modeling the atmospheric effects, especially production of odd nitrogen compounds and subsequent depletion of ozone, by solar protons associated with the Carrington event. This study combines approaches from two previous studies of the atmospheric effect of this event. We investigate changes in NOy compounds as well as depletion of O3 using a two-dimensional atmospheric chemistry and dynamics model. Atmospheric ionization is computed using a range-energy relation with four different proxy proton spectra associated with more recent well-known solar proton events. We find that changes in atmospheric constituents are in reasonable agreement with previous studies, but effects of the four proxy spectra use...

Thomas, Brian C; Snyder, Brock R

2011-01-01T23:59:59.000Z

84

AN ANALYTIC RADIATIVE-CONVECTIVE MODEL FOR PLANETARY ATMOSPHERES  

Science Conference Proceedings (OSTI)

We present an analytic one-dimensional radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power-law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric-pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries; (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation; and (3) strongly irradiated giant planets (including hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

Robinson, Tyler D. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Catling, David C., E-mail: robinson@astro.washington.edu [Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 (United States)

2012-09-20T23:59:59.000Z

85

Numerical Modeling of the Atmosphere with an Isentropic Vertical Coordinate  

Science Conference Proceedings (OSTI)

In constructing a numerical model of the atmosphere, we must choose an appropriate vertical coordinate. Among the various possibilities, isentropic vertical coordinates such as the ?-coordinate seem to have the greatest potential, in spite of the ...

Yueh-Jiuan G. Hsu; Akio Arakawa

1990-10-01T23:59:59.000Z

86

A Moist Benchmark Calculation for Atmospheric General Circulation Models  

Science Conference Proceedings (OSTI)

A benchmark calculation is designed to compare the climate and climate sensitivity of atmospheric general circulation models (AGCMs). The experimental setup basically follows that of the aquaplanet experiment (APE) proposed by Neale and Hoskins, ...

Myong-In Lee; Max J. Suarez; In-Sik Kang; Isaac M. Held; Daehyun Kim

2008-10-01T23:59:59.000Z

87

Measurements, Models, and Hypotheses in the Atmospheric Sciences  

Science Conference Proceedings (OSTI)

Measurements in atmospheric science sometimes determine universal functions, but more commonly data are collected in the form of case studies. Models are conceptual constructs that can be used to make predictions about the outcomes of ...

David A. Randall; Bruce A. Wielicki

1997-03-01T23:59:59.000Z

88

Comprehensive Model Simulation of Thermal Tides in the Martian Atmosphere  

Science Conference Proceedings (OSTI)

This paper discusses the thermotidal oscillations in simulations performed with a newly developed comprehensive general circulation model of the Martian atmosphere. With reasonable assumptions about the effective thermal inertia of the planetary ...

R. John Wilson; Kevin Hamilton

1996-05-01T23:59:59.000Z

89

Stable Schemes for Nonlinear Vertical Diffusion in Atmospheric Circulation Models  

Science Conference Proceedings (OSTI)

The intensity of vertical mixing in atmospheric models generally depends on wind shear and static stability, making the diffusion process nonlinear. Traditional implicit numerical schemes, which treat the variables to be diffused implicitly but ...

Claude Girard; Yves Delage

1990-03-01T23:59:59.000Z

90

An Interpretation of Atmospheric Low-Order Models  

Science Conference Proceedings (OSTI)

Low-order models (LOMs) arising in various popular fluid dynamic and atmospheric problems are shown to be equivalent to coupled three-mode nonlinear systems known in mechanics as Volterra gyrostats. The Volterra equations of the gyrostat differ ...

Alexander Gluhovsky; Ernest Agee

1997-03-01T23:59:59.000Z

91

Modeling Climate Variability in the Tropical Atlantic Atmosphere  

Science Conference Proceedings (OSTI)

Climate variability in the tropical Atlantic sector as represented in six atmospheric general circulation models is examined. On the annual mean, most simulations overestimate wind stress away from the equator although much of the variability can ...

Jiande Wang; James A. Carton

2003-12-01T23:59:59.000Z

92

Optimizing Parameters in an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

An efficient method to optimize the parameter values of the subgrid parameterizations of an atmospheric general circulation model is described. The method is based on the downhill simplex minimization of a cost function computed from the ...

C. A. Severijns; W. Hazeleger

2005-09-01T23:59:59.000Z

93

Climate Drift in a Coupled Land–Atmosphere Model  

Science Conference Proceedings (OSTI)

A coupled land–atmosphere climate model is examined for evidence of climate drift in the land surface state variable of soil moisture. The drift is characterized as pathological error growth in two different ways. First is the systematic error ...

Paul A. Dirmeyer

2001-02-01T23:59:59.000Z

94

Nonhydrostatic Atmospheric Modeling Using a Combined Cartesian Grid  

Science Conference Proceedings (OSTI)

A new method for representing topography on a Cartesian grid is applied to a two-dimensional nonhydrostatic atmospheric model to achieve highly precise simulations over steep terrain. The shaved cell method based on finite-volume discretization ...

Hiroe Yamazaki; Takehiko Satomura

2010-10-01T23:59:59.000Z

95

An Accurate and Efficient Radiation Algorithm for Middle Atmosphere Models  

Science Conference Proceedings (OSTI)

An accurate, efficient, and user-friendly radiation algorithm is developed for calculating net radiative heating rate in middle atmosphere models. The Curtis matrix interpolation scheme originally developed by Zhu is adopted with explicit ...

Xun Zhu

1994-12-01T23:59:59.000Z

96

Slow Instabilities in Tropical Ocean Basin–Global Atmosphere Models  

Science Conference Proceedings (OSTI)

The effect of ocean boundaries on instability in coupled ocean-natmosphere models is determined. Eigenvalues and eigenvectors are calculated for coupled systems featuring an ocean basin bounded zonally by a flat continent. The atmosphere is ...

Anthony C. Hirst

1988-03-01T23:59:59.000Z

97

Atmospheric Correction of Satellite Signal in Solar Domain: Impact of Improved Molecular Spectroscopy  

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

Atmospheric Correction of Satellite Signal in Solar Atmospheric Correction of Satellite Signal in Solar Domain: Impact of Improved Molecular Spectroscopy A. P. Trishchenko Canada Centre for Remote Sensing Ottawa, Ontario, Canada B. Hwang Intermap Technologies Corp. Calgary, Canada Z. Li University of Maryland and The Earth System Science Interdisciplinary Center College Park, Maryland Introduction Atmospheric correction of satellite measurements is a major step in the retrieval of surface reflective properties. It involves removing the effect of gaseous absorption as well as correcting for the effect of an atmospheric molecular and particulate scattering. In the past few years, there has been significant advancement in our knowledge of the absorbing properties of various atmospheric radiatively active

98

Coastal Atmospheric Circulation around an Idealized Cape during Wind-Driven Upwelling Studied from a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The study analyzes atmospheric circulation around an idealized coastal cape during summertime upwelling-favorable wind conditions simulated by a mesoscale coupled ocean–atmosphere model. The domain resembles an eastern ocean boundary with a ...

Natalie Perlin; Eric D. Skyllingstad; Roger M. Samelson

2011-03-01T23:59:59.000Z

99

Response of a Coupled Ocean–Atmosphere Model to Increasing Atmospheric Carbon Dioxide: Sensitivity to the Rate of Increase  

Science Conference Proceedings (OSTI)

The influence of differing rates of increase of the atmospheric CO2 concentration on the climatic response is investigated using a coupled ocean–atmosphere model. Five transient integrations are performed each using a different constant ...

Ronald J. Stouffer; Syukuro Manabe

1999-08-01T23:59:59.000Z

100

Multiple-Century Response of a Coupled Ocean-Atmosphere Model to an Increase of Atmospheric Carbon Dioxide  

Science Conference Proceedings (OSTI)

To speculate on the future change of climate over several centuries, three 500-year integrations of a coupled ocean-atmosphere model were performed. In addition to the standard integration in which the atmospheric concentration of carbon dioxide ...

Syukuro Manabe; Ronald J. Stouffer

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

The Physical Properties of the Atmosphere in the New Hadley Centre Global Environmental Model (HadGEM1). Part I: Model Description and Global Climatology  

Science Conference Proceedings (OSTI)

The atmospheric component of the new Hadley Centre Global Environmental Model (HadGEM1) is described and an assessment of its mean climatology presented. HadGEM1 includes substantially improved representations of physical processes, increased ...

G. M. Martin; M. A. Ringer; V. D. Pope; A. Jones; C. Dearden; T. J. Hinton

2006-04-01T23:59:59.000Z

102

Discrete second order adjoints in atmospheric chemical transport modeling  

Science Conference Proceedings (OSTI)

Atmospheric chemical transport models (CTMs) are essential tools for the study of air pollution, for environmental policy decisions, for the interpretation of observational data, and for producing air quality forecasts. Many air quality studies require ... Keywords: 65, Chemical transport models, Hessian singular vectors, Optimization, Second order adjoints, Sensitivity analysis, Stiff equations

Adrian Sandu; Lin Zhang

2008-06-01T23:59:59.000Z

103

Retrospective ENSO Forecasts: Sensitivity to Atmospheric Model and Ocean Resolution  

Science Conference Proceedings (OSTI)

Results are described from a series of 40 retrospective forecasts of tropical Pacific SST, starting 1 January and 1 July 1980–99, performed with several coupled ocean–atmosphere general circulation models sharing the same ocean model—the Modular ...

Edwin K. Schneider; Ben P. Kirtman; David G. DeWitt; Anthony Rosati; Link Ji; Joseph J. Tribbia

2003-12-01T23:59:59.000Z

104

Bringing Climate Models into Agreement with Observations of Atmospheric Absorption  

Science Conference Proceedings (OSTI)

A comparison of the output of two data assimilation models with a quasi-global, multiyear set of monthly mean observations shows that the models underestimate the amount of solar energy absorbed in the atmosphere by 15–30 W m?2, out of a total of ...

Albert Arking

1999-06-01T23:59:59.000Z

105

A Model of Tropical Ocean-Atmosphere Interaction  

Science Conference Proceedings (OSTI)

A model is used to study ocean-atmosphere interaction in the tropics. The model ocean consists of the single baroclinic mode of a two-layer ocean. Thermodynamics in the upper layer is highly parameterized. If the interface is sufficiently shallow ...

Julian P. McCreary Jr.

1983-02-01T23:59:59.000Z

106

Hybrid fluid/kinetic modeling of Pluto's escaping atmosphere  

E-Print Network (OSTI)

Predicting the rate of escape and thermal structure of Pluto's upper atmosphere in preparation for the New Horizons Spacecraft encounter in 2015 is important for planning and interpreting the expected measurements. Having a moderate Jeans parameter Pluto's atmosphere does not fit the classic definition of Jeans escape for light species escaping from the terrestrial planets, nor does it fit the hydrodynamic outflow from comets and certain exoplanets. It has been proposed for some time that Pluto lies in the region of slow-hydrodynamic escape. Using a hybrid fluid/molecular-kinetic model, we previously demonstrated the typical implementation of this model fails to correctly describe the appropriate temperature structure for the upper atmosphere for solar minimum conditions. Here we used a time-dependent solver to allow us to extend those simulations to higher heating rates and we examined fluid models in which Jeans-like escape expressions are used for the upper boundary conditions. We compare these to our hybr...

Erwin, Justin T; Johnson, Robert E

2012-01-01T23:59:59.000Z

107

New Model Atmospheres: Testing the Solar Spectrum in the UV  

E-Print Network (OSTI)

We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the SYNTHE series of codes developed by Kurucz. As a first step we have tested if SYNTHE is able to handle these models which go down to log tau(Ross)= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000--4500 A at high resolution (R=522,000). Within this initial test we have found that layers at optical depths with log tau(Ross) spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.

Rodríguez-Merino, L H; Bertone, E; Chavez, M; Buzzoni, A

2007-01-01T23:59:59.000Z

108

New Model Atmospheres: Testing the Solar Spectrum in the UV  

E-Print Network (OSTI)

We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the SYNTHE series of codes developed by Kurucz. As a first step we have tested if SYNTHE is able to handle these models which go down to log tau(Ross)= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000--4500 A at high resolution (R=522,000). Within this initial test we have found that layers at optical depths with log tau(Ross) spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.

L. H. Rodriguez-Merino; O. Cardona; E. Bertone; M. Chavez; A. Buzzoni

2007-10-05T23:59:59.000Z

109

Atmospheric Longwave Irradiance Uncertainty: Pyrgeometers Compared to an Absolute Sky-Scanning Radiometer, Atmospheric Emitted Radiance Interferometer, and Radiative Transfer Model Calculations  

SciTech Connect

Because atmospheric longwave radiation is one of the most fundamental elements of an expected climate change, there has been a strong interest in improving measurements and model calculations in recent years. Important questions are how reliable and consistent are atmospheric longwave radiation measurements and calculations and what are the uncertainties? The First International Pyrgeometer and Absolute Sky-scanning Radiometer Comparison, which was held at the Atmospheric Radiation Measurement program's Souther Great Plains site in Oklahoma, answers these questions at least for midlatitude summer conditions and reflects the state of the art for atmospheric longwave radiation measurements and calculations. The 15 participating pyrgeometers were all calibration-traced standard instruments chosen from a broad international community. Two new chopped pyrgeometers also took part in the comparison. And absolute sky-scanning radiometer (ASR), which includes a pyroelectric detector and a reference blackbody source, was used for the first time as a reference standard instrument to field calibrate pyrgeometers during clear-sky nighttime measurements. Owner-provided and uniformly determined blackbody calibration factors were compared. Remarkable improvements and higher pyrgeometer precision were achieved with field calibration factors. Results of nighttime and daytime pyrgeometer precision and absolute uncertainty are presented for eight consecutive days of measurements, during which period downward longwave irradiance varied between 260 and 420 W m-2. Comparisons between pyrgeometers and the absolute ASR, the atmospheric emitted radiance interferometer, and radiative transfer models LBLRTM and MODTRAN show a surprisingly good agreement of <2 W m-2 for nighttime atmospheric longwave irradiance measurements and calculations.

Philipona, J. R.; Dutton, Ellsworth G.; Stoffel, T.; Michalsky, Joseph J.; Reda, I.; Stifter, Armin; Wendling, Peter; Wood, Norm; Clough, Shepard A.; Mlawer, Eli J.; Anderson, Gail; Revercomb, Henry E.; Shippert, Timothy R.

2001-06-04T23:59:59.000Z

110

A Global Nonhydrostatic Semi-Lagrangian Atmospheric Model with Orography  

Science Conference Proceedings (OSTI)

A global nonhydrostatic semi-implicit semi-Lagrangian (SISL) atmospheric model with orography has been developed. The height-based terrain-following ?z coordinate of Gal-Chen and Somerville is used to incorporate the orography. A 3D vector form ...

Jian-Hua Qian; Fredrick H. M. Semazzi; Jeffrey S. Scroggs

1998-03-01T23:59:59.000Z

111

A Global Nonhydrostatic Semi-Lagrangian Atmospheric Model without Orography  

Science Conference Proceedings (OSTI)

A semi-Lagrangian semi-implicit finite-difference nonhydrostatic global atmospheric model on a flat terrain has been developed. Starting from the initialized ECMWF analysis of 0000 UTC 15 January 1979, a series of 5-day test runs have been ...

Frederick H. M. Semazzi; Jian-Hua Qian; Jeffrey S. Scroggs

1995-08-01T23:59:59.000Z

112

Modeling land-surface/atmosphere dynamics for CHAMMP  

SciTech Connect

Project progress is described on a DOE CHAMP project to model the land-surface/atmosphere coupling in a heterogeneous environment. This work is a collaboration between scientists at Iowa State University and the University of New Hampshire. Work has proceeded in two areas: baseline model coupling and data base development for model validation. The core model elements (land model, atmosphere model) have been ported to the Principal Investigator's computing system and baseline coupling has commenced. The initial target data base is the set of observations from the FIFE field campaign, which is in the process of being acquired. For the remainder of the project period, additional data from the region surrounding the FIFE site and from other field campaigns will be acquired to determine how to best extrapolate results from the initial target region to the rest of the globe. In addition, variants of the coupled model will be used to perform experiments examining resolution requirements and coupling strategies for land-atmosphere coupling in a heterogeneous environment.

Gutowski, W.J. Jr.

1993-01-01T23:59:59.000Z

113

Modeling atmospheric effects of the September 1859 Solar Flare  

E-Print Network (OSTI)

We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data.

Thomas, B; Melott, A; Thomas, Brian; Jackman, Charles; Melott, Adrian

2006-01-01T23:59:59.000Z

114

Modeling atmospheric effects of the September 1859 Solar Flare  

E-Print Network (OSTI)

We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data.

Brian Thomas; Charles Jackman; Adrian Melott

2006-12-21T23:59:59.000Z

115

The Ocean–Land–Atmosphere Model (OLAM). Part I: Shallow-Water Tests  

Science Conference Proceedings (OSTI)

The Ocean–Land–Atmosphere Model (OLAM) has been developed to extend the capabilities of the Regional Atmospheric Modeling System (RAMS) to a global model domain. OLAM adopts many features of its predecessor, including physical parameterizations, ...

Robert L. Walko; Roni Avissar

2008-11-01T23:59:59.000Z

116

A Hidden Markov Model Perspective on Regimes and Metastability in Atmospheric Flows  

Science Conference Proceedings (OSTI)

In this study, data from three atmospheric models are analyzed to investigate the existence of atmospheric flow regimes despite nearly Gaussian statistics of the planetary waves in these models. A hierarchy of models is used, which describes the ...

Christian Franzke; Daan Crommelin; Alexander Fischer; Andrew J. Majda

2008-04-01T23:59:59.000Z

117

White dwarf atmosphere models with Ly-$?$ opacity in the analysis of the white dwarf cooling sequence of NGC 6397  

E-Print Network (OSTI)

We discuss the importance of pure hydrogen white dwarf atmosphere models with Ly-$\\rm \\alpha$ far red wing opacity in the analysis of the white dwarf cooling sequence of the globular cluster NGC 6397. Our recently improved atmosphere models account for the previously missing opacity from the Ly-$\\rm \\alpha$ hydrogen line broadened by collisions of the absorbing hydrogen atoms with molecular and atomic hydrogen. These models are the first that well reproduce the UV colors and spectral energy distributions of cool white dwarfs with $T_{\\rm eff}age of NGC 6397 derived from the white dwarf cooling sequence using atmosphere models that do not include the correct Ly-$\\alpha$ opacity is underestimated by $\\sim 0.5$ Gyr. Our analysis shows that it is essential to use white dwarf atmosphere models with Ly-$\\rm \\alpha$ opacity for precise dating of old stellar populations from white dwarf cooling sequences.

Piotr M. Kowalski

2007-08-28T23:59:59.000Z

118

Interannual Tropical Rainfall Variability in General Circulation Model Simulations Associated with the Atmospheric Model Intercomparison Project  

Science Conference Proceedings (OSTI)

The interannual variability of rainfall over the Indian subcontinent, the African Sahel, and the Nordeste region of Brazil have been evaluated in 32 models for the period 1979–88 as part of the Atmospheric Model Intercomparison Project (AMIP). ...

K. R. Sperber; T. N. Palmer

1996-11-01T23:59:59.000Z

119

SECHIBA, a New Set of Parameterizations of the Hydrologic Exchanges at the Land-Atmosphere Interface within the LMD Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

A simple parameterization of the hydrologic exchanges between the soil-vegetation system and the atmosphere (SECHIBA) has been developed for use within atmospheric general circulation models (AGCM).

Nathale I. Ducoudré; Katia Laval; Alain Perrier

1993-02-01T23:59:59.000Z

120

Improved Time to Publication in Journal of Geophysical Research-Atmospheres  

Science Conference Proceedings (OSTI)

Timely publication of manuscripts is important to authors and readers. AGU has significantly accelerated both the review and production processes for the Journal of Geophysical Research-Atmospheres (JGR-Atmospheres). Via a number of mechanisms (e.g., shortening the time allotted for reviewer selection, manuscript reviews, and revisions), the mean time to first decision has been decreased from 98 days in 2007 to 50 days in 2011, and the mean time to final decision has been decreased from 132 days in 2007 to 71 days in 2011. By implementing a new content management system, adjusting the workflow for improved efficiency, requesting authors to proofread their manuscripts quicker, and improving monitoring and follow-up to author and vendor queries, the mean production time from manuscript acceptance to publication has been decreased from 128 days in 2010 to only 56 days in 2012. Thus, in the past few years the mean time to publication of JGRAtmospheres has been cut in half. These milestones have been achieved with no loss of quality of presentation or content. In addition, online posting of "papers in press" on JGR-Atmosphere’s home page typically occurs within a few days after acceptance. JGR-Atmospheres editors thank manuscript reviewers, authors, and AGU staff who have greatly contributed to the more timely review and publication processes. This information will be updated periodically on the JGR-Atmospheres home page. A chart showing the average time from acceptance to publication for all of AGU’s journals is available at http://www.agu.org/pubs/pdf/31May2012_Timeliness_Chart.pdf.

de Gouw, Joost A.; Ghan, Steven J.; Pryor, Sara; Rudich, Yinon; Zhang, Renyi

2012-07-03T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

A Coupled Dynamical Ocean–Energy Balance Atmosphere Model for Paleoclimate Studies  

Science Conference Proceedings (OSTI)

The Bern3D coupled three-dimensional dynamical ocean–energy balance atmosphere model is introduced and the atmospheric component is discussed in detail. The model is of reduced complexity, developed to perform extensive sensitivity studies and ...

Stefan P. Ritz; Thomas F. Stocker; Fortunat Joos

2011-01-01T23:59:59.000Z

122

Heating and Kinetic Energy Dissipation in the NCAR Community Atmosphere Model  

Science Conference Proceedings (OSTI)

Conservation of energy and the incorporation of parameterized heating in an atmospheric model are discussed. Energy conservation is used to unify the treatment of heating and kinetic energy dissipation within the Community Atmosphere Model, ...

Byron A. Boville; Christopher S. Bretherton

2003-12-01T23:59:59.000Z

123

Atmospheric Transports, the Thermohaline Circulation, and Flux Adjustments in a Simple Coupled Model  

Science Conference Proceedings (OSTI)

A theoretical analysis of the interactions between atmospheric meridional transports and the thermohaline circulation is presented, using a four-box ocean-atmosphere model in one hemisphere. The model is a simplified version of that developed by ...

Jochem Marotzke; Peter H. Stone

1995-06-01T23:59:59.000Z

124

Validation and Sensitivity Analysis of a New Atmosphere–Soil–Vegetation Model  

Science Conference Proceedings (OSTI)

This paper describes details, validation, and sensitivity analysis of a new atmosphere–soil–vegetation model. The model consists of one-dimensional multilayer submodels for atmosphere, soil, and vegetation and radiation schemes for the ...

Haruyasu Nagai

2002-02-01T23:59:59.000Z

125

A Numerical Study of Climatic Oscillations Using a Coupled Atmosphere–Ocean Primitive Equation Model  

Science Conference Proceedings (OSTI)

A coupled atmosphere-ocean primitive equation model is developed. It is a free-dimensional general circulation model, with two layers in the atmosphere and two layers in the ocean and includes solar radiation, longwave radiation, sensible heating,...

Xiong-Shan Chen

1984-03-01T23:59:59.000Z

126

A Multiscale Nonhydrostatic Atmospheric Model Using Centroidal Voronoi Tesselations and C-Grid Staggering  

Science Conference Proceedings (OSTI)

The formulation of a fully compressible nonhydrostatic atmospheric model called the Model for Prediction Across Scales–Atmosphere (MPAS-A) is described. The solver is discretized using centroidal Voronoi meshes and a C-grid staggering of the ...

William C. Skamarock; Joseph B. Klemp; Michael G. Duda; Laura D. Fowler; Sang-Hun Park; Todd D. Ringler

2012-09-01T23:59:59.000Z

127

Thermal Tides in the Atmosphere of Venus: Comparison of Model Results with Observations  

Science Conference Proceedings (OSTI)

A linearized primitive equation (LPE) model is developed to study thermal tides in the atmosphere of Venus. The LPE model describes diurnal and semidiurnal oscillations of a cyclostrophically balanced atmosphere in which zonal velocity varies ...

Judith Burt Pechmann; Andrew P. Ingersoll

1984-11-01T23:59:59.000Z

128

Toward the Use of Coupled Atmospheric and Hydrologic Models at Regional Scale  

Science Conference Proceedings (OSTI)

The purpose of this study is to present the possibilities offered by coupled atmospheric and hydrologic models as a new tool to validate and interpret results produced by atmospheric models. The advantages offered by streamflow observations are ...

Robert Benoit; Pierre Pellerin; Nick Kouwen; Harold Ritchie; Norman Donaldson; Paul Joe; E. D. Soulis

2000-06-01T23:59:59.000Z

129

Adjustment to Radiative Forcing in a Simple Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

This study calculates the adjustment to radiative forcing in a simple model of a mixed layer ocean coupled to the overlying atmosphere. One application of the model is to calculate how dust aerosols perturb the temperature of the atmosphere and ...

R. L. Miller

2012-11-01T23:59:59.000Z

130

Interdecadal Variability in a Hybrid Coupled Ocean–Atmosphere–Sea Ice Model  

Science Conference Proceedings (OSTI)

Interdecadal climate variability in an idealized coupled ocean–atmosphere–sea-ice model is studied. The ocean component is a fully three-dimensional primitive equation model and the atmospheric component is a two-dimensional (2D) energy balance ...

S. Kravtsov; M. Ghil

2004-07-01T23:59:59.000Z

131

Standard model atmospheres for A-type stars and non-LTE effects  

E-Print Network (OSTI)

Abstract. The current status of NLTE model atmosphere calculations of A type stars is reviewed. During the last decade the research has concentrated on solving the restricted NLTE line formation problem for trace elements assuming LTE model atmospheres. There is a general lack of calculated NLTE line blanketed model atmospheres for A type stars, despite the availability of powerful methods and computer codes that are able to solve this task. Some directions for future model atmosphere research are suggested.

Daniela Kor?áková

2004-01-01T23:59:59.000Z

132

Regional forecasting with global atmospheric models; Third year report  

SciTech Connect

This report was prepared by the Applied Research Corporation (ARC), College Station, Texas, under subcontract to Pacific Northwest Laboratory (PNL) as part of a global climate studies task. The task supports site characterization work required for the selection of a potential high-level nuclear waste repository and is part of the Performance Assessment Scientific Support (PASS) Program at PNL. The work is under the overall direction of the Office of Civilian Radioactive Waste Management (OCRWM), US Department of Energy Headquarters, Washington, DC. The scope of the report is to present the results of the third year`s work on the atmospheric modeling part of the global climate studies task. The development testing of computer models and initial results are discussed. The appendices contain several studies that provide supporting information and guidance to the modeling work and further details on computer model development. Complete documentation of the models, including user information, will be prepared under separate reports and manuals.

Crowley, T.J.; North, G.R.; Smith, N.R. [Applied Research Corp., College Station, TX (United States)

1994-05-01T23:59:59.000Z

133

A New Single-Layer Urban Canopy Model for Use in Mesoscale Atmospheric Models  

Science Conference Proceedings (OSTI)

A new single-layer urban canopy model for use in mesoscale atmospheric models is developed and validated. The urban canopy model represents a built-up area as a street canyon, two facing buildings, and a road. In this model, the two facing walls ...

Young-Hee Ryu; Jong-Jin Baik; Sang-Hyun Lee

2011-09-01T23:59:59.000Z

134

Principal Modes of Atmospheric Variability in Model Atmospheres with and without Anomalous Sea Surface Temperature Forcing in the Tropical Pacific  

Science Conference Proceedings (OSTI)

Principal modes of low-frequency atmospheric variability and the influence of sea surface temperature anomalies on such modes are investigated by examining the output from two general circulation model experiments. In the first experiment (the “...

In-Sik Kang; Ngar-Cheung Lau

1986-11-01T23:59:59.000Z

135

Internal Versus SST-Forced Atmospheric Variability as Simulated by an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

The variability of atmospheric flow is analyzed by separating it into an internal part due to atmospheric dynamics only and an external (or forced) part due to the variability of sea surface temperature forcing. The two modes of variability are ...

Ali Harzallah; Robert Sadourny

1995-03-01T23:59:59.000Z

136

Improved Normalization of the Size Distribution of Atmospheric Particles Retrieved from Aureole Measurements Using the Diffraction Approximation  

Science Conference Proceedings (OSTI)

This paper describes an improvement in the diffraction approximation used to retrieve the size distribution of atmospheric particles from solar aureole radiance measurements. Normalization using total optical thickness based on measurement of the ...

J. G. DeVore

2011-08-01T23:59:59.000Z

137

Perfromance analysis of the Parallel Community Atmosphere Model (CAM) application  

E-Print Network (OSTI)

Efficient execution of parallel applications requires insight into how the parallel system features impact the performance of the application. Significant experimental analysis and the development of performance models enhance the understanding of such an impact. Deep understanding of an application’s major kernels and their design leads to a better understanding of the application’s performance, and hence, leads to development of better performance models. The Community Atmosphere Model (CAM) is the latest in a series of global atmospheric models developed at the National Center for Atmospheric Research (NCAR) as a community tool for NCAR and the university research community. This work focuses on analyzing CAM and understanding the impact of different architectures on this application. In the analysis of CAM, kernel coupling, which quantifies the interaction between adjacent and chains of kernels in an application, is used. All experiments are conducted on four parallel platforms: NERSC (National Energy Research Scientific Computing Center) Seaborg, SDSC (San Diego Supercomputer Center) DataStar P655, DataStar P690 and PSC (Pittsburgh Supercomputing Center) Lemieux. Experimental results indicate that kernel coupling gave an insight into many of the application characteristics. One important characteristic of CAM is that its performance is heavily dependent on a parallel platform memory hierarchy; different cache sizes and different cache policies had the major effect on CAM’s performance. Also, coupling values showed that although CAM’s kernels share many data structures, most of the coupling values are still destructive (i.e., interfering with each other so as to adversely affect performance). The kernel coupling results helps developers in pointing out the bottlenecks in memory usage in CAM. The results obtained from processor partitioning are significant in helping CAM users in choosing the right platform to run CAM.

Shawky Sharkawi, Sameh Sherif

2006-08-01T23:59:59.000Z

138

An Evaluation with the Fourier Amplitude Sensitivity Test (FAST) of Which Land-Surface Parameters Are of Greatest Importance in Atmospheric Modeling  

Science Conference Proceedings (OSTI)

Land-surface parameterizations based on a statistical-dynamical approach have been suggested recently to improve the representation of the surface forcing from heterogeneous land in atmospheric models. With this approach, land-surface ...

Dan C. Collins; Roni Avissar

1994-05-01T23:59:59.000Z

139

Atmospheric Dispersion Modeling: Challenges of the Fukushima Daiichi Response  

Science Conference Proceedings (OSTI)

The U.S. Department of Energy’s (DOE) National Atmospheric Release Advisory Center (NARAC) provided a wide range of predictions and analyses as part of the response to the Fukushima Daiichi Nuclear Power Plant accident. This work encompassed: weather forecasts and atmospheric transport predictions, estimates of possible dose in Japan based on hypothetical U.S. Nuclear Regulatory Commission scenarios of potential radionuclide releases, predictions of possible plume arrival times and dose levels at U.S. locations, and source estimation and plume model refinement. An overview of NARAC response activities is provided, along with a more in-depth discussion of some of NARAC’s preliminary source reconstruction analyses. NARAC optimized the overall agreement of model predictions to dose rate measurements using statistical comparisons of data and model values paired in space and time. Estimated emission rates varied depending on the choice of release assumptions (e.g., time-varying vs. constant release rates), the radionuclide mix, meteorology, and/or the radiological data used in the analysis. Results were found to be consistent with other studies within expected uncertainties, despite the application of different source estimation methodologies and the use of significantly different radiological measurement data. A discussion of some of the operational and scientific challenges encountered during the response, along with recommendations for future work, is provided.

Sugiyama, Gayle [Lawrence Livermore National Laboratory; Nasstrom, John [Lawrence Livermore National Laboratory; Pobanz, Brenda [Lawrence Livermore National Laboratory; Foster, Kevin [Lawrence Livermore National Laboratory; Simpson, Matthew [Lawrence Livermore National Laboratory; Vogt, Phil [Lawrence Livermore National Laboratory; Aluzzi, Fernando [Lawrence Livermore National Laboratory; Homann, Steve [Lawrence Livermore National Laboratory

2012-05-01T23:59:59.000Z

140

Computational Fluid Dynamics Modeling of Atmospheric Flow Applied to Wind Energy Research.  

E-Print Network (OSTI)

??High resolution atmospheric flow modeling using computational fluid dynamics (CFD) has many applications in the wind energy industry. A well designed model can accurately calculate… (more)

Russell, Alan

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

A Coupled Air–Sea Mesoscale Model: Experiments in Atmospheric Sensitivity to Marine Roughness  

Science Conference Proceedings (OSTI)

A coupled air–sea numerical model comprising a mesoscale atmospheric model, a marine circulation model, and a surface wave model is presented. The coupled model is tested through simulations of an event of frontal passage through the Lake Erie ...

Jordan G. Powers; Mark T. Stoelinga

2000-01-01T23:59:59.000Z

142

A Simple Atmospheric Model of Surface Heat Flux for Use in Ocean Modeling Studies  

Science Conference Proceedings (OSTI)

A simple model of the lower atmospheric layers and land/sea ice surface is described and analyzed. The model is able to depict with reasonable accuracy the global ocean heat fluxes. Due to the model's simplicity, insight into the mechanisms ...

Richard Kleeman; Scott B. Power

1995-01-01T23:59:59.000Z

143

Seasonal Prediction of Sea Surface Temperature Anomalies Using a Suite of 13 Coupled Atmosphere–Ocean Models  

Science Conference Proceedings (OSTI)

Improved seasonal prediction of sea surface temperature (SST) anomalies over the global oceans is the theme of this paper. Using 13 state-of-the-art coupled global atmosphere–ocean models and 13 yr of seasonal forecasts, the performance of ...

T. N. Krishnamurti; Arindam Chakraborty; Ruby Krishnamurti; William K. Dewar; Carol Anne Clayson

2006-12-01T23:59:59.000Z

144

An Improved Model of Direct Gauge Mediation  

E-Print Network (OSTI)

We present a new, improved model of gauge mediation of dynamical SUSY Breaking: the model does not have gauge messengers or $\\sim 10$ TeV scalars charged under the Standard Model (SM), thus avoiding the problem of negative (mass)$^2$ for supersymmetric SM (SSM) scalars faced by some earlier models. The gauge mediation is direct, i.e., the messengers which communicate SUSY breaking to the SSM fields carry quantum numbers of the gauge group which breaks SUSY. These messenger fields couple to a modulus field. The model has a very simple particle content: the modulus and the messengers are the only chiral superfields (other than the SSM fields) in the model. The inverted hierarchy mechanism is used to generate a local SUSY breaking minimum for the modulus field in a perturbative regime thus making the model calculable.

Agashe, K S

1998-01-01T23:59:59.000Z

145

Improving Air Conditioner and Heat Pump Modeling  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Improving Air-Conditioner Improving Air-Conditioner and Heat Pump Modeling Building America Stakeholders Meeting Jon Winkler March 2, 2012 2 * How do you recommend the most cost-effective A/C? Simple Question 3 Solution Whole-House Simulation Tool A/C Information * SEER 13 * SEER 14 * SEER 15 * SEER 16 * SEER 17 * SEER 18 * SEER 21 Annualized Cooling Cost (Energy + Equipment) 4 Background * Power, capacity and SHR vary with: o Outdoor temperature o Entering wetbulb o Air mass flow rate o Part load ratio Power Sensible Capacity Latent Capacity * How to accurately and easily model A/C performance? 5 Background: Model Development * A/C modeling utilizes two types of input o Rated values (capacity, efficiency, etc.) o Performance curves Capacity 1 / Efficiency 6 Background: Manufacturer's Data

146

Sensitivity of Simulated Climate to Horizontal and Vertical Resolution in the ECHAM5 Atmosphere Model  

Science Conference Proceedings (OSTI)

The most recent version of the Max Planck Institute for Meteorology atmospheric general circulation model, ECHAM5, is used to study the impact of changes in horizontal and vertical resolution on seasonal mean climate. In a series of Atmospheric ...

E. Roeckner; R. Brokopf; M. Esch; M. Giorgetta; S. Hagemann; L. Kornblueh; E. Manzini; U. Schlese; U. Schulzweida

2006-08-01T23:59:59.000Z

147

Regional Climate Change in East Asia Simulated by an Interactive Atmosphere–Soil–Vegetation Model  

Science Conference Proceedings (OSTI)

A regional coupled soil–vegetation–atmosphere model is used to study changes and interactions between climate and the ecosystem in East Asia due to increased atmospheric CO2. The largest simulated climate changes are due to the radiative ...

Ming Chen; David Pollard; Eric J. Barron

2004-02-01T23:59:59.000Z

148

Generalized Inversion of Tropical Atmosphere–Ocean Data and a Coupled Model of the Tropical Pacific  

Science Conference Proceedings (OSTI)

It is hypothesized that the circulation of the tropical Pacific Ocean and atmosphere satisfies the equations of a simple coupled model to within errors having specified covariances, and that the Tropical Atmosphere–Ocean array (TAO) measures the ...

Andrew F. Bennett; Boon S. Chua; D. Ed Harrison; Michael J. McPhaden

1998-07-01T23:59:59.000Z

149

Entropy in Climate Models. Part II: Horizontal Structure of Atmospheric Entropy Production  

Science Conference Proceedings (OSTI)

The global horizontal structure of atmospheric entropy has been investigated. In energy balance models, the horizontal distribution of the atmospheric internal entropy production rate has been obtained. Based on the entropy balance relation, this ...

J. Li; Petr Chylek

1994-06-01T23:59:59.000Z

150

Interannual to Decadal Predictability in a Coupled Ocean–Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

The predictability of the coupled ocean–atmosphere climate system on interannual to decadal timescales has been studied by means of ensemble forecast experiments with a global coupled ocean–atmosphere general circulation model. Over most parts of ...

A. Grötzner; M. Latif; A. Timmermann; R. Voss

1999-08-01T23:59:59.000Z

151

A Two-Box Model of a Zonal Atmospheric Circulation in the Tropics  

Science Conference Proceedings (OSTI)

A simple fixed-SST model of a zonal circulation in the tropical atmosphere has been developed that has separate boxes for the ascending and descending branches of the atmospheric circulation. This circulation resembles the Walker circulation. ...

Michael A. Kelly; David A. Randall

2001-10-01T23:59:59.000Z

152

A January Angular Momentum Balance in the OSU Two-Level Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

The atmospheric angular momentum balance is studied by analyzing the data during a simulated January of the Oregon State University two-level atmospheric general circulation model. Monthly zonal means of the Coriolis torques, the vertical ...

J-W. Kim; W. Grady

1982-05-01T23:59:59.000Z

153

The Evolution of Climate Sensitivity and Climate Feedbacks in the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

The major evolution of the National Center for Atmospheric Research Community Atmosphere Model (CAM) is used to diagnose climate feedbacks, understand how climate feedbacks change with different physical parameterizations, and identify the ...

A. Gettelman; J. E. Kay; K. M. Shell

2012-03-01T23:59:59.000Z

154

The Extratropical 40-Day Oscillation in the UCLA General Circulation Model. Part I: Atmospheric Angular Momentum  

Science Conference Proceedings (OSTI)

Variations in atmospheric angular momentum (AAM) are examined in a three-year simulation of the large-scale atmosphere with perpetual January forcing. The simulation is performed with a version of the UCLA general circulation model that contains ...

S. L. Marcus; M. Ghil; J. O. Dickey

1994-06-01T23:59:59.000Z

155

One-Way Coupling of an Atmospheric and a Hydrologic Model in Colorado  

Science Conference Proceedings (OSTI)

This paper examines the accuracy of high-resolution nested mesoscale model simulations of surface climate. The nesting capabilities of the atmospheric fifth-generation Pennsylvania State University (PSU)–National Center for Atmospheric Research (...

L. E. Hay; M. P. Clark; M. Pagowski; G. H. Leavesley; W. J. Gutowski Jr.

2006-08-01T23:59:59.000Z

156

Distributed Ocean–Atmosphere Modeling and Sensitivity to the Coupling Flux Precision: The CATHODe Project  

Science Conference Proceedings (OSTI)

The authors present the distribution of a coupled ocean–atmosphere global circulation model. The atmospheric (ARPEGE) and the oceanic (OPA) components run separately at different sites; the coupling is achieved through the exchanges of fluxes via ...

C. Cassou; P. Noyret; E. Sevault; O. Thual; L. Terray; D. Beaucourt; M. Imbard

1998-04-01T23:59:59.000Z

157

Implementation of a Two-Way Interactive Atmospheric and Ecological Model and Its Application to the Central United States  

Science Conference Proceedings (OSTI)

A coupled Regional Atmospheric Modeling System (RAMS) and ecosystem (CENTURY) modeling system has been developed to study regional-scale two-way interactions between the atmosphere and biosphere. Both atmospheric forcings and ecological ...

Lixin Lu; Roger A. Pielke Sr.; Glen E. Liston; William J. Parton; Dennis Ojima; Melannie Hartman

2001-03-01T23:59:59.000Z

158

A Coupled Atmosphere–Wave–Ocean Modeling System: Simulation of the Intensity of an Idealized Tropical Cyclone  

Science Conference Proceedings (OSTI)

A coupled atmosphere–wave–ocean modeling system (CAWOMS) based on the integration of atmosphere–wave, atmosphere–ocean, and wave–current interaction processes is developed. The component models consist of the Weather Research and Forecasting (WRF)...

Bin Liu; Huiqing Liu; Lian Xie; Changlong Guan; Dongliang Zhao

2011-01-01T23:59:59.000Z

159

Introducing an Absolute Cavity Pyrgeometer for Improving the Atmospheric Longwave Irradiance Measurement (Presentation)  

SciTech Connect

Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG. A total of 408 readings was collected over three different clear nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two pyrgeometers that are traceable to WISG. Further development and characterization of the ACP might contribute to the effort of improving the uncertainty and traceability of WISG to SI.

Reda, I.; Hansen, L.; Zeng, J.

2012-08-01T23:59:59.000Z

160

Evaluation of the Multiscale Modeling Framework Using Data from the Atmospheric Radiation Measurement Program  

Science Conference Proceedings (OSTI)

In a recently developed approach to climate modeling, called the multiscale modeling framework (MMF), a two-dimensional cloud-resolving model (CRM) is embedded into each grid column of the Community Atmospheric Model (CAM), replacing traditional ...

Mikhail Ovtchinnikov; Thomas Ackerman; Roger Marchand; Marat Khairoutdinov

2006-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Variational Objective Analysis for Atmospheric Field Programs: A Model Assessment  

Science Conference Proceedings (OSTI)

The objective of this study is to examine the effectiveness of the variational objective analysis (VOA) for producing realistic diagnoses of atmospheric field program data. Simulations from the Naval Research Laboratory's Coupled Ocean/Atmosphere ...

D. E. Waliser; J. A. Ridout; S. Xie; M. Zhang

2002-12-01T23:59:59.000Z

162

Using Variable Resolution Meshes to Model Tropical Cyclones in the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

A statically-nested, variable-mesh option has recently been introduced into the Community Atmosphere Model’s (CAM) Spectral Element (SE) dynamical core that has become the default in CAM version 5.3. This paper presents a series of tests of ...

Colin M. Zarzycki; Christiane Jablonowski; Mark A. Taylor

163

The GISS Global Climate-Middle Atmosphere Model. Part I: Model Structure and Climatology  

Science Conference Proceedings (OSTI)

The GISS global climate model (Hansen et al.) has been extended to include the middle atmosphere up to an altitude of approximately 85 km. The model has the full array of processes used for climate research, i.e., numerical solutions of the ...

D. Rind; R. Suozzo; N. K. Balachandran; A. Lacis; G. Russell

1988-02-01T23:59:59.000Z

164

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite-element method designed for fully unstructured quadrilateral ... Keywords: atmospheric modeling, dynamical core, global circulation model, parallel scalability, spectral elements

John M. Dennis; Jim Edwards; Katherine J. Evans; Oksana Guba; Peter H. Lauritzen; Arthur A. Mirin; Amik St-Cyr; Mark A. Taylor; Patrick H. Worley

2012-02-01T23:59:59.000Z

165

A sustained oscillation in a toy-model of the coupled atmosphere-ocean system  

E-Print Network (OSTI)

Interaction between atmospheric mid-latitude flow and wind-driven ocean circulation is studied coupling two idealized low-order spectral models. The barotropic Charney-DeVore model with three components simulates a bimodal mid-latitude atmospheric circulation in a channel with two stable flow patterns induced by topography. The wind-driven ocean double gyre circulation in a square basin (of half the channel length) is modeled by an equivalent barotropic formulation of the Veronis model with 21 components, which captures Rossby-wave dynamics and nonlinear decadal variability. When coupled, the atmosphere forces the ocean by wind-stress while, simultaneously, the ocean affects the atmosphere by thermal forcing in terms of a vorticity source. Coupled atmosphere-ocean simulations show two stable flow patterns associated with the topographically induced atmospheric bimodality and a sustained oscillation due to interaction between atmospheric bimodality and oceanic Rossby dynamics. The oscillation is of inter-annua...

Bothe, Oliver

2011-01-01T23:59:59.000Z

166

Final Report - From Measurements to Models: Cross-Comparison of Measured and Simulated Behavioral States of the Atmosphere  

SciTech Connect

The ARM sites and the ARM Mobile Facility (AMF) were constructed to make measurements of the atmosphere and radiation system in order to quantify deficiencies in the simulation of clouds within models and to make improvements in those models. While the measurement infrastructure of ARM is well-developed and a model parameterization testbed capability has been established, additional effort is needed to develop statistical techniques which permit the comparison of simulation output from atmospheric models with actual measurements. Our project establishes a new methodology for objectively comparing ARM measurements to the outputs of leading global climate models and reanalysis data. The quantitative basis for this comparison is provided by a statistical procedure which establishes an exhaustive set of mutually-exclusive, recurring states of the atmosphere from sets of multivariate atmospheric and cloud conditions, and then classifies multivariate measurements or simulation outputs into those states. Whether measurements and models classify the atmosphere into the same states at specific locations through time provides an unequivocal comparison result. Times and locations in both geographic and state space of model-measurement agreement and disagreement will suggest directions for the collection of additional measurements at existing sites, provide insight into the global representativeness of the current ARM sites (suggesting locations and times for use of the AMF), and provide a basis for improvement of models. Two different analyses were conducted: One, using the Parallel Climate Model, focused on an IPCC climate change scenario and clusters that characterize long-term changes in the hydrologic cycle. The other, using the GISS Model E GCM and the ARM Active Remotely Sensed Cloud Layers product, explored current climate cloud regimes in the Tropical West Pacific.

Del Genio, Anthony D; Hoffman, Forrest M; Hargrove, Jr, William W

2007-10-22T23:59:59.000Z

167

High Resolution Atmospheric Modeling for Wind Energy Applications  

SciTech Connect

The ability of the WRF atmospheric model to forecast wind speed over the Nysted wind park was investigated as a function of time. It was found that in the time period we considered (August 1-19, 2008), the model is able to predict wind speeds reasonably accurately for 48 hours ahead, but that its forecast skill deteriorates rapidly after 48 hours. In addition, a preliminary analysis was carried out to investigate the impact of vertical grid resolution on the forecast skill. Our preliminary finding is that increasing vertical grid resolution does not have a significant impact on the forecast skill of the WRF model over Nysted wind park during the period we considered. Additional simulations during this period, as well as during other time periods, will be run in order to validate the results presented here. Wind speed is a difficult parameter to forecast due the interaction of large and small length scale forcing. To accurately forecast the wind speed at a given location, the model must correctly forecast the movement and strength of synoptic systems, as well as the local influence of topography / land use on the wind speed. For example, small deviations in the forecast track or strength of a large-scale low pressure system can result in significant forecast errors for local wind speeds. The purpose of this study is to provide a preliminary baseline of a high-resolution limited area model forecast performance against observations from the Nysted wind park. Validating the numerical weather prediction model performance for past forecasts will give a reasonable measure of expected forecast skill over the Nysted wind park. Also, since the Nysted Wind Park is over water and some distance from the influence of terrain, the impact of high vertical grid spacing for wind speed forecast skill will also be investigated.

Simpson, M; Bulaevskaya, V; Glascoe, L; Singer, M

2010-03-18T23:59:59.000Z

168

Role of a Cumulus Parameterization Scheme in Simulating Atmospheric Circulation and Rainfall in the Nine-Layer Goddard Laboratory for Atmospheres General Circulation Model  

Science Conference Proceedings (OSTI)

A coarse (4° × 5° × 9-sigma level) version of the Goddard Laboratory for Atmospheres (GLA) General Circulation Model (GCM) was used to investigate the influence of a cumulus convection scheme on the simulated atmospheric circulation and ...

Y. C. Sud; Winston C. Chao; G. K. Walker

1992-04-01T23:59:59.000Z

169

Global Ocean Surface Wave Simulation Using a Coupled Atmosphere–Wave Model  

Science Conference Proceedings (OSTI)

This study describes a 29-yr (1981–2009) global ocean surface gravity wave simulation generated by a coupled atmosphere–wave model using NOAA/GFDL’s High-Resolution Atmosphere Model (HiRAM) and the WAVEWATCH III surface wave model developed and ...

Yalin Fan; Shian-Jiann Lin; Isaac M. Held; Zhitao Yu; Hendrik L. Tolman

2012-09-01T23:59:59.000Z

170

Physical Interpretation of the Adjoint Functions for Sensitivity Analysis of Atmospheric Models  

Science Conference Proceedings (OSTI)

The adjoint functions for an atmospheric model are the solution to a system of equations derived from a differential form of the model's equations. The adjoint functions can be used to calculate efficiently the sensitivity of one of the model's ...

Matthew C. G. Hall; Dan G. Cacuci

1983-10-01T23:59:59.000Z

171

Estimating Model-Error Covariances for Application to Atmospheric Data Assimilation  

Science Conference Proceedings (OSTI)

Forecast-error statistics have traditionally been used to investigate model performance and to calculate analysis weights for atmospheric data assimilation. Forecast error has two components: the model error, caused by model imperfections, and ...

Roger Daley

1992-08-01T23:59:59.000Z

172

An Evaluation of the Software System Dependency of a Global Atmospheric Model  

Science Conference Proceedings (OSTI)

This study presents the dependency of the simulation results from a global atmospheric numerical model on machines with different hardware and software systems. The global model program (GMP) of the Global/Regional Integrated Model system (GRIMs) ...

Song-You Hong; Myung-Seo Koo; Jihyeon Jang; Jung-Eun Esther Kim; Hoon Park; Min-Su Joh; Ji-Hoon Kang; Tae-Jin Oh

2013-11-01T23:59:59.000Z

173

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

SciTech Connect

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

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

2009-04-02T23:59:59.000Z

174

A Study of Persistence in the Land–Atmosphere System Using a General Circulation Model and Observations  

Science Conference Proceedings (OSTI)

Persistence in the land–atmosphere system simulated with the National Center for Atmosphere Research Community Climate Model Version 2 (CCM2) coupled with the Biosphere–Atmosphere Transfer Scheme (BATS) is examined. BATS simulates various ...

Yongqiang Liu; Roni Avissar

1999-08-01T23:59:59.000Z

175

Evaluation of a Regional Atmospheric Model Using Measurements of Surface Heat Exchange Processes from a Site in Antarctica  

Science Conference Proceedings (OSTI)

A regional atmospheric climate model with a horizontal grid spacing of 55 km has been used to simulate the Antarctic atmosphere during an austral summer period. ECMWF reanalyses were used to force the atmospheric prognostic variables from the ...

Nicole P. M. van Lipzig; Erik van Meijgaard; Johannes Oerlemans

1999-09-01T23:59:59.000Z

176

A Study of Persistence in the Land–Atmosphere System with a Fourth-Order Analytical Model  

Science Conference Proceedings (OSTI)

In a companion paper, Y. Liu and R. Avissar analyzed the features of persistence in the land–atmosphere system simulated with the National Center for Atmospheric Research Community Climate Model Version 2 coupled with the Biosphere–Atmosphere ...

Yongqiang Liu; Roni Avissar

1999-08-01T23:59:59.000Z

177

Improved modeling techniques for turbomachinery flow fields  

DOE Green Energy (OSTI)

This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbomachinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. This will be accomplished in a cooperative program by Penn State University and the Allison Engine Company. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tenor.

Lakshminarayana, B.; Fagan, J.R. Jr.

1995-12-31T23:59:59.000Z

178

Evaluating Aspects of the Community Land and Atmosphere Models (CLM3 and CAM3) Using a Dynamic Global Vegetation Model  

Science Conference Proceedings (OSTI)

The Community Land Model version 3 (CLM3) Dynamic Global Vegetation Model (CLM–DGVM) is used diagnostically to identify land and atmospheric model biases that lead to biases in the simulated vegetation. The CLM–DGVM driven with observed ...

Gordon B. Bonan; Samuel Levis

2006-06-01T23:59:59.000Z

179

Dual-Doppler Lidar Measurements for Improving Dispersion Models  

Science Conference Proceedings (OSTI)

Dispersion of pollutants in the urban atmosphere is a subject that is presently under much investigation. In this paper the variables used in turbulent dispersion and plume rise schemes of the Met Office Nuclear Accident Model (NAME) are ...

Chris G. Collier; Fay Davies; Karen E. Bozier; Anthony R. Holt; Doug R. Middleton; Guy N. Pearson; Stephan Siemen; Dave V. Willetts; Graham J. G. Upton; Rob I. Young

2005-06-01T23:59:59.000Z

180

Formation of algae growth constitutive relations for improved algae modeling.  

SciTech Connect

This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

Gharagozloo, Patricia E.; Drewry, Jessica L.

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Model atmospheres for M (sub)dwarfs; 1, the base model grid  

E-Print Network (OSTI)

We have calculated a grid of more than 700 model atmospheres valid for a wide range of parameters encompassing the coolest known M~dwarfs M~subdwarfs and brown dwarf candidates: 1500\\le \\teff \\le 4000\\,K, 3.5\\le \\log(g)\\le 5.5, and -4.0\\le { [M/H]}\\le +0.5. Our equation of state includes 105 molecules and up to 27 ionization stages of 39 elements. In the calculations of the base grid of model atmospheres presented here, we include over 300 molecular bands of 4 molecules (TiO, VO, CaH, FeH) in the JOLA approximation, the water opacity of Ludwig (1971), collision induced opacities, b-f and f-f atomic processes, as well as about 2 million spectral lines selected from a list with more than 42 million atomic and 24 million molecular (H_2, CH, NH, OH, MgH, SiH, C_2, CN, CO, SiO) lines. High-resolution synthetic spectra are obtained using an opacity sampling method. The model atmospheres and spectra are calculated with the generalized stellar atmosphere code PHOENIX, assuming LTE, plane-parallel geometry, energy (ra...

Hauschildt, P H

1996-01-01T23:59:59.000Z

182

Modeling a Sensor to Improve its Efficacy  

E-Print Network (OSTI)

Robots rely on sensors to provide them with information about their surroundings. However, high-quality sensors can be extremely expensive and cost-prohibitive. Thus many robotic systems must make due with lower-quality sensors. Here we demonstrate via a case study how modeling a sensor can improve its efficacy when employed within a Bayesian inferential framework. As a test bed we employ a robotic arm that is designed to autonomously take its own measurements using an inexpensive LEGO light sensor to estimate the position and radius of a white circle on a black field. The light sensor integrates the light arriving from a spatially distributed region within its field of view weighted by its Spatial Sensitivity Function (SSF). We demonstrate that by incorporating an accurate model of the light sensor SSF into the likelihood function of a Bayesian inference engine, an autonomous system can make improved inferences about its surroundings. The method presented here is data-based, fairly general, and made with plu...

Malakar, N K; Knuth, K H

2013-01-01T23:59:59.000Z

183

Climate Simulations for 1951–2050 with a Coupled Atmosphere–Ocean Model  

Science Conference Proceedings (OSTI)

The authors simulate climate change for 1951–2050 using the GISS SI2000 atmospheric model coupled to HYCOM, a quasi-isopycnal ocean model (“ocean E”), and contrast the results with those obtained using the same atmosphere coupled to a passive Q-...

Shan Sun; James E. Hansen

2003-09-01T23:59:59.000Z

184

Coupled Atmosphere-Ocean Model Simulations of El Niño/Southern Oscillation with and without an Active Indian Ocean  

Science Conference Proceedings (OSTI)

An atmospheric general circulation model (GCM) was coupled with an ocean GCM covering the Pacific. This coupled model (PAC) was integrated over a 30-years period. The PAC model stimulates well the mean seasonally varying atmospheric and ocean ...

T. Nagai; Y. Kitamura; M. Endoh; T. Tokioka

1995-01-01T23:59:59.000Z

185

Atmospheric Plasma Processing of SiC: A Novel Method to Improve ...  

Science Conference Proceedings (OSTI)

Symposium, Innovative Processing and Synthesis of Ceramics, Glasses and Composites. Presentation Title, Atmospheric Plasma Processing of SiC: A Novel  ...

186

A global coupled Eulerian-Lagrangian model and 1 1 km CO2 surface flux dataset for high-resolution atmospheric CO2 transport simulations  

Science Conference Proceedings (OSTI)

Abstract. We designed a method to simulate atmospheric CO2 concentrations at several continuous observation sites around the globe using surface fluxes at a very high spatial resolution. The simulations presented in this study were performed using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA), comprising a Lagrangian particle dispersion model coupled to a global atmospheric tracer transport model with prescribed global surface CO2 flux maps at a 1 1 km resolution. The surface fluxes used in the simulations were prepared by assembling the individual components of terrestrial, oceanic and fossil fuel CO2 fluxes. This experimental setup (i.e. a transport model running at a medium resolution, coupled to a high-resolution Lagrangian particle dispersion model together with global surface fluxes at a very high resolution), which was designed to represent high-frequency variations in atmospheric CO2 concentration, has not been reported at a global scale previously. Two sensitivity experiments were performed: (a) using the global transport model without coupling to the Lagrangian dispersion model, and (b) using the coupled model with a reduced resolution of surface fluxes, in order to evaluate the performance of Eulerian-Lagrangian coupling and the role of high-resolution fluxes in simulating high-frequency variations in atmospheric CO2 concentrations. A correlation analysis between observed and simulated atmospheric CO2 concentrations at selected locations revealed that the inclusion of both Eulerian-Lagrangian coupling and highresolution fluxes improves the high-frequency simulations of the model. The results highlight the potential of a coupled Eulerian-Lagrangian model in simulating high-frequency atmospheric CO2 concentrations at many locations worldwide. The model performs well in representing observations of atmospheric CO2 concentrations at high spatial and temporal resolutions, especially for coastal sites and sites located close to sources of large anthropogenic emissions. While this study focused on simulations of CO2 concentrations, the model could be used for other atmospheric compounds with known estimated emissions.

Ganshin, A [Central Aerological Observatory; Oda, T [National Institute for Environmental Studies, Japan; Saito, M [National Institute for Environmental Studies, Japan; Maksyutov, S [National Institute for Environmental Studies, Japan; Valsala, V [National Institute for Environmental Studies, Japan; Andres, Robert Joseph [ORNL; Fischer, R [University of London; Lowry, D [University of London; Lukyanov, A [Central Aerological Observatory; Matsueda, H [Meteorological Research Institute, Japan; Nisbet, E [University of London; Rigby, M [University of Bristol, UK; Sawa, Y [Meteorological Research Institute, Japan; Toumi, R [Imperial College, London; Tsuboi, K [Meteorological Research Institute, Japan; Varlagin, A [A.N. Severtsov Institute of Ecology and Evolution, Russia; Zhuravlev, R [Central Aerological Observatory

2012-01-01T23:59:59.000Z

187

Scientific Final Report: COLLABORATIVE RESEARCH: CONTINUOUS DYNAMIC GRID ADAPTATION IN A GLOBAL ATMOSPHERIC MODEL: APPLICATION AND REFINEMENT  

SciTech Connect

This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the 'physics' of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.

William J. Gutowski; Joseph M. Prusa, Piotr K. Smolarkiewicz

2012-04-09T23:59:59.000Z

188

Forecast Skill of the Madden–Julian Oscillation in Two Canadian Atmospheric Models  

Science Conference Proceedings (OSTI)

The output of two global atmospheric models participating in the second phase of the Canadian Historical Forecasting Project (HFP2) is utilized to assess the forecast skill of the Madden–Julian oscillation (MJO). The two models are the third ...

Hai Lin; Gilbert Brunet; Jacques Derome

2008-11-01T23:59:59.000Z

189

The Effects of Topography on the Atmospheric Energetics in. a Low-Resolution General Circulation Model  

Science Conference Proceedings (OSTI)

An analysis is made of the effect of orography on the atmospheric energetics in a low-resolution general circulation model to determine the temporal and scale dependency of these effects. The numerical model is a global, spectral, primitive ...

Yun-Qi Ni; Bette L. Otto-Bliesner; David D. Houghton

1986-07-01T23:59:59.000Z

190

Entropy in Climate Models. Part I: Vertical Structure of Atmospheric Entropy Production  

Science Conference Proceedings (OSTI)

The vertical atmospheric entropy structure has been investigated using one-dimensional radiative–convective models. A method for evaluating radiation entropy is proposed. In the models, the entropy radiation is dealt with in a way parallel to the ...

J. Li; Petr Chýlek; G. B. Lesins

1994-06-01T23:59:59.000Z

191

Using the Radiative Kernel Technique to Calculate Climate Feedbacks in NCAR’s Community Atmospheric Model  

Science Conference Proceedings (OSTI)

Climate models differ in their responses to imposed forcings, such as increased greenhouse gas concentrations, due to different climate feedback strengths. Feedbacks in NCAR’s Community Atmospheric Model (CAM) are separated into two components: ...

Karen M. Shell; Jeffrey T. Kiehl; Christine A. Shields

2008-05-01T23:59:59.000Z

192

A One-Dimensional Interactive Soil-Atmosphere Model for Testing Formulations of Surface Hydrology  

Science Conference Proceedings (OSTI)

A model representing a soil-atmosphere column in a GCM is developed for off-line testing of GCM soil hydrology parameterizations. Repeating three representative GCM sensitivity experiments with this one-dimensional model demonstrates that, to ...

Randal D. Koster; Peter S. Eagleson

1990-06-01T23:59:59.000Z

193

DART/CAM: An Ensemble Data Assimilation System for CESM Atmospheric Models  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM) has been interfaced to the Data Assimilation Research Testbed (DART), a community facility for ensemble data assimilation. This provides a large set of data assimilation tools for climate model research and ...

Kevin Raeder; Jeffrey L. Anderson; Nancy Collins; Timothy J. Hoar; Jennifer E. Kay; Peter H. Lauritzen; Robert Pincus

2012-09-01T23:59:59.000Z

194

Dynamics and Thermodynamics of a Warming Event in a Coupled Tropical Atmosphere–Ocean Model  

Science Conference Proceedings (OSTI)

A simple coupled ocean–atmosphere model, similar to that of Zebiak and Cane, is used to examine the dynamic and thermodynamic processes associated with El Niño/Southern Oscillation (ENSO). The model is run for 300 years. The interannual ...

David S. Battisti

1988-10-01T23:59:59.000Z

195

Evaluation of Tropospheric Water Vapor Simulations from the Atmospheric Model Intercomparison Project  

Science Conference Proceedings (OSTI)

Simulations of humidity from 28 general circulation models for the period 1979–88 from the Atmospheric Model Intercomparison Project are compared with observations from radiosondes over North America and the globe and with satellite microwave ...

Dian J. Gaffen; Richard D. Rosen; David A. Salstein; James S. Boyle

1997-07-01T23:59:59.000Z

196

North Atlantic Interannual Variability in a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The primary mode of sea surface temperature variability in the North Atlantic on interannual timescales during winter is examined in a coupled ocean–atmosphere model. The model, developed at die Geophysical Fluid Dynamics Laboratory, is global in ...

Thomas L. Delworth

1996-10-01T23:59:59.000Z

197

Large-Scale Atmospheric Forcing by Southeast Pacific Boundary Layer Clouds: A Regional Model Study  

Science Conference Proceedings (OSTI)

A regional model is used to study the radiative effect of boundary layer clouds over the southeast Pacific on large-scale atmosphere circulation during August–October 1999. With the standard settings, the model simulates reasonably well the large-...

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

2005-04-01T23:59:59.000Z

198

A Lagrangian Long-Range Transport Model with Atmospheric Boundary Layer Chemistry  

Science Conference Proceedings (OSTI)

The present paper reports on the combination of a chemical model for the gas phase chemistry of the atmospheric boundary layer, with a Lagrangian model for the long-range transport of air pollutants. The resulting combined chemistry/transport ...

Anton Eliassen; Jørgen Saltbones; Frode Stordal; Øystein Hov; Ivar S. A. Isaksen; Frode Stordal

1982-11-01T23:59:59.000Z

199

A Multiscale Model for the Planetary and Synoptic Motions in the Atmosphere  

Science Conference Proceedings (OSTI)

A reduced asymptotic model valid for the planetary and synoptic scales in the atmosphere is presented. The model is derived by applying a systematic multiple scales asymptotic method to the full compressible flow equations in spherical geometry. ...

S. I. Dolaptchiev; R. Klein

200

The Representation of Atmospheric Motion in Models of Regional-Scale Air Pollution  

Science Conference Proceedings (OSTI)

A method is developed for generating ensembles of wind fields for use in regional scale (1000 km) models of transport and diffusion. The underlying objective is a methodology for representing atmospheric motion in applied air pollution models ...

Robert G. Lamb; Saroj K. Hati

1987-07-01T23:59:59.000Z

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201

The Role of the Nonlocal Transport in Modeling the Shear-Driven Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

In this work the role played by the transport equations including nonlocal terms in simulating the atmospheric turbulence is investigated. Two different models are compared: the first one is a standard E–? model solving two dynamical equations ...

E. Ferrero; M. Racca

2004-06-01T23:59:59.000Z

202

Application of the E – ? Turbulence Closure Model to the Neutral and Stable Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

In the E – ? turbulence model an eddy-exchange coefficient is evaluated from the turbulent kinetic energy E and viscous dissipation ?. In this study we will apply the E – ? model to the stable and neutral atmospheric boundary layer. A discussion ...

P. G. Duynkerke

1988-03-01T23:59:59.000Z

203

Ensemble Simulations with Coupled Atmospheric Dynamic and Dispersion Models: Illustrating Uncertainties in Dosage Simulations  

Science Conference Proceedings (OSTI)

Ensemble simulations made using a coupled atmospheric dynamic model and a probabilistic Lagrangian puff dispersion model were employed in a forensic analysis of the transport and dispersion of a toxic gas that may have been released near Al ...

Thomas T. Warner; Rong-Shyang Sheu; James F. Bowers; R. Ian Sykes; Gregory C. Dodd; Douglas S. Henn

2002-05-01T23:59:59.000Z

204

A Parameterization of Heterogeneous Land Surfaces for Atmospheric Numerical Models and Its Impact on Regional Meteorology  

Science Conference Proceedings (OSTI)

Natural land surfaces are usually heterogeneous over the resolvable scales considered in atmospheric numerical models. Therefore, model surface parameterizations that assume surface homogeneity may fail to represent the surface forcing ...

R. Avissar; R. A. Pielke

1989-10-01T23:59:59.000Z

205

Scalability of Parallel Gridpoint Limited-Area Atmospheric Models. Part I: Explicit Time-Integration Schemes  

Science Conference Proceedings (OSTI)

A performance model of parallel domain decompositions for explicit gridpoint limited-area atmospheric models is developed, and the parallel scalability is analyzed. Given a set of reasonable assumptions, a two-dimensional horizontal decomposition ...

Roar Skålin

1997-06-01T23:59:59.000Z

206

The Impact of Spectral Nudging on Cloud Simulation with a Regional Atmospheric Model  

Science Conference Proceedings (OSTI)

The impact of spectral nudging on cloud simulation with a regional atmospheric model was examined. Simulated cloudiness of the Regional Model (REMO) and the Spectrally Nudged REMO (SN-REMO) were intercompared and evaluated with satellite-derived ...

Insa Meinke; Beate Geyer; Frauke Feser; Hans von Storch

2006-06-01T23:59:59.000Z

207

A General Circulation Experiment with a Coupled Atmosphere, Ocean and Sea Ice Model  

Science Conference Proceedings (OSTI)

This paper describes the construction and results of a comprehensive, three-dimensional general circulation model (GCM) of the earth's climate. The model, developed at the National Center for Atmospheric Research (NCAR), links separate existing ...

Warren M. Washington; Albert J. Semtner Jr.; Gerald A. Meehl; David J. Knight; Thomas A. Mayer

1980-12-01T23:59:59.000Z

208

Simulations of Mid-Holocene Climate Using an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

The authors describe a first paleoclimatological application of the Canadian Centre for Climate Modelling and Analysis atmospheric general circulation model (AGCM) to simulate the climate state 6000 calendar years before present (6 kyr BP). ...

G. Vettoretti; W. R. Peltier; N. A. McFarlane

1998-10-01T23:59:59.000Z

209

Kinematics of Eddy–Mean Flow Interaction in an Idealized Atmospheric Model  

Science Conference Proceedings (OSTI)

The authors analyze atmospheric variability simulated in a two-layer baroclinic ?-channel quasigeostrophic model by combining Eulerian and feature-tracking analysis approaches. The leading mode of the model's low-frequency variability (LFV) is ...

Sergey Kravtsov; Sergey K. Gulev

2013-08-01T23:59:59.000Z

210

Modeling the Atmospheric General Circulation Using a Spherical Geodesic Grid: A New Class of Dynamical Cores  

Science Conference Proceedings (OSTI)

This paper documents the development and testing of a new type of atmospheric dynamical core. The model solves the vorticity and divergence equations in place of the momentum equation. The model is discretized in the horizontal using a geodesic ...

Todd D. Ringler; Ross P. Heikes; David A. Randall

2000-07-01T23:59:59.000Z

211

Implied Ocean Heat Transports in the Standard and Superparameterized Community Atmospheric Models  

Science Conference Proceedings (OSTI)

Implied ocean heat transport (To) based on net surface energy budgets is computed for two versions of the Community Atmospheric Model (CAM, version 3.0) general circulation model (GCM). The first version is the standard CAM with parameterized ...

Charlotte A. DeMott; David A. Randall; Marat Khairoutdinov

2010-04-01T23:59:59.000Z

212

Dynamical Core of an Atmospheric General Circulation Model on a Yin–Yang Grid  

Science Conference Proceedings (OSTI)

The three-dimensional dynamical core of an atmospheric general circulation model employing Yin–Yang grid is developed and examined. Benchmark test cases based on the shallow-water model configuration are first performed to examine the validity of ...

Yuya Baba; Keiko Takahashi; Takeshi Sugimura; Koji Goto

2010-10-01T23:59:59.000Z

213

A Gaussian Plume Model of Atmospheric Dispersion Based on Second-Order Closure  

Science Conference Proceedings (OSTI)

A practical model of atmospheric dispersion of a passive tracer based on systematic reduction of the second-order closure transport equations using Gaussian shape assumptions is presented. The model is comparable with conventional Gaussian plume ...

R. I. Sykes; W. S. Lewellen; S. F. Parker

1986-03-01T23:59:59.000Z

214

Experimental Tropical Cyclone Prediction Using the GFDL 25-km-Resolution Global Atmospheric Model  

Science Conference Proceedings (OSTI)

This paper describes a forecasting configuration of the Geophysical Fluid Dynamics Laboratory (GFDL) High-resolution Atmospheric Model (HiRAM). HiRAM represents an early attempt in unifying, within a global modeling framework, the capabilities of ...

Jeffrey S. Gall; Isaac Ginis; Shian-Jiann Lin; Timothy P. Marchok; Jan-Huey Chen

2011-12-01T23:59:59.000Z

215

Advantages of a Topographically Controlled Runoff Simulation in a Soil–Vegetation–Atmosphere Transfer Model  

Science Conference Proceedings (OSTI)

Two methods to incorporate subgrid variability in soil moisture and runoff production into soil–vegetation–atmosphere transfer (SVAT) models are compared: 1) the variable infiltration capacity model approach (VIC), and 2) a modified “TOPMODEL” ...

Kirsten Warrach; Marc Stieglitz; Heinz-Theo Mengelkamp; Ehrhard Raschke

2002-04-01T23:59:59.000Z

216

Turbulence Spectra and Dissipation Rates in a Wind Tunnel Model of the Atmospheric Convective Boundary Layer  

Science Conference Proceedings (OSTI)

A model of the atmospheric convective boundary layer (CBL) is realized in the thermally stratified wind tunnel of the Institute of Hydrology and Water Resources, University of Karlsruhe. Further experimental results from this model are presented. ...

Rolf Kaiser; Evgeni Fedorovich

1998-02-01T23:59:59.000Z

217

A Multiscale Model for the Planetary and Synoptic Motions in the Atmosphere  

Science Conference Proceedings (OSTI)

A reduced asymptotic model valid for the planetary and synoptic scales in the atmosphere is presented. The model is derived by applying a systematic multiple-scales asymptotic method to the full compressible-flow equations in spherical geometry. ...

Stamen I. Dolaptchiev; Rupert Klein

2013-09-01T23:59:59.000Z

218

NOMADS: A Climate and Weather Model Archive at the National Oceanic and Atmospheric Administration  

Science Conference Proceedings (OSTI)

An online archive of real-time and historical weather and climate model output and observationaldata is now available from the National Oceanic and Atmospheric Administration (NOAA). This archive, known asthe NOAA National Operational Model ...

Glenn K. Rutledge; Jordan Alpert; Wesley Ebisuzaki

2006-03-01T23:59:59.000Z

219

Variability in a Nonlinear Model of the Atmosphere with Zonally Symmetric Forcing  

Science Conference Proceedings (OSTI)

The variability in a two-level nonlinear atmospheric model is examined. The model domain is spherical. The sole forcing is a zonally symmetric parameterization of the December-February insulation. An extended 1500 day run is carefully analyzed.

Harry H. Hendon; Dennis L. Hartmann

1985-12-01T23:59:59.000Z

220

A Coupled Atmosphere?Fire Model: Convective Feedback on Fire-Line Dynamics  

Science Conference Proceedings (OSTI)

The object of this paper is to describe and demonstrate the necessity and utility of a coupled atmosphere-fire model: a three-dimensional, time-dependent wildfire simulation model, based on the primitive equations of motion and thermodynamics, ...

Terry L. Clark; Mary Ann Jenkins; Janice Coen; David Packham

1996-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Initialization of Soil-Water Content in Regional-Scale Atmospheric Prediction Models  

Science Conference Proceedings (OSTI)

The purpose of this study is to demonstrate the feasibility of determining the soil-water content fields required as initial conditions for land surface components within atmospheric prediction models. This is done using a model of the hydrologic ...

Christopher B. Smith; Mercedes N. Lakhtakia; William J. Capehart; Toby N. Carlson

1994-04-01T23:59:59.000Z

222

Testing the Annular Mode Autocorrelation Time Scale in Simple Atmospheric General Circulation Models  

Science Conference Proceedings (OSTI)

A new diagnostic for measuring the ability of atmospheric models to reproduce realistic low-frequency variability is introduced in the context of Held and Suarez’s 1994 proposal for comparing the dynamics of different general circulation models. ...

Edwin P. Gerber; Sergey Voronin; Lorenzo M. Polvani

2008-04-01T23:59:59.000Z

223

Modeling Bulk Atmospheric Drainage Flow in a Valley  

Science Conference Proceedings (OSTI)

Most simulations of bulk valley-drainage flows depend heavily on parameterizations. The 1984 Atmospheric Studies in Complex Terrain (ASCOT) field experiment in Brush Creek Valley, Colorado, provided an unprecedented density of measurements in a ...

Ronald J. Dobosy

1989-09-01T23:59:59.000Z

224

Intermediate Models of Planetary Circulations in the Atmosphere and Ocean  

Science Conference Proceedings (OSTI)

Large-scale extratropical motions (with dimensions comparable to, or somewhat smaller than, the planetary radius) in the atmosphere and ocean exhibit a more restricted range of phenomena than are admissible in the primitive equations for fluid ...

James C. McWilliams; Peter R. Gent

1980-08-01T23:59:59.000Z

225

A Simulation of Atmospheric Blocking with a Forced Barotropic Model  

Science Conference Proceedings (OSTI)

Nearly stationary states (NSSs) of the barotropic vorticity equation (BVE) on the sphere that are closely related to observed atmospheric blocking patterns have recently been derived. Examining the way such NSSs affect integrations of the BVE is ...

Jeffrey L. Anderson

1995-08-01T23:59:59.000Z

226

Mesoscale Modeling of Boundary Layer Refractivity and Atmospheric Ducting  

Science Conference Proceedings (OSTI)

In this study four mesoscale forecasting systems were used to investigate the four-dimensional structure of atmospheric refractivity and ducting layers that occur within evolving synoptic conditions over the eastern seaboard of the United States. ...

Tracy Haack; Changgui Wang; Sally Garrett; Anna Glazer; Jocelyn Mailhot; Robert Marshall

2010-12-01T23:59:59.000Z

227

Model Atmospheres for M (Sub)Dwarfs: I. The base model grid  

E-Print Network (OSTI)

We have calculated a grid of more than 700 model atmospheres valid for a wide range of parameters encompassing the coolest known M~dwarfs, M~subdwarfs and brown dwarf candidates: $1500\\le \\teff \\le 4000\\,$K, $3.5\\le \\log(g)\\le 5.5$, and $-4.0\\le { [M/H]}\\le +0.5$. Our equation of state includes 105 molecules and up to 27 ionization stages of 39 elements. In the calculations of the base grid of model atmospheres presented here, we include over 300 molecular bands of 4 molecules (TiO, VO, CaH, FeH) in the JOLA approximation, the water opacity of Ludwig (1971), collision induced opacities, b-f and f-f atomic processes, as well as about 2 million spectral lines selected from a list with more than 42 million atomic and 24 million molecular (H$_2$, CH, NH, OH, MgH, SiH, C$_2$, CN, CO, SiO) lines. High-resolution synthetic spectra are obtained using an opacity sampling method. The model atmospheres and spectra are calculated with the generalized stellar atmosphere code PHOENIX, assuming LTE, plane-parallel geometry, energy (radiative plus convective) conservation, and hydrostatic equilibrium. The model spectra give close agreement with observations of M~dwarfs across a wide spectral range from the blue to the near-IR, with one notable exception: the fit to the water bands. We discuss several practical applications of our model grid, e.g., broadband colors derived from the synthetic spectra. In light of current efforts to identify genuine brown dwarfs, we also show how low-resolution spectra of cool dwarfs vary with surface gravity, and how the high-resolution line profile of the Li~I resonance doublet depends on the Li abundance.

France Allard; Peter H. Hauschildt

1996-01-25T23:59:59.000Z

228

HIGH-RESOLUTION ATMOSPHERIC ENSEMBLE MODELING AT SRNL  

Science Conference Proceedings (OSTI)

The High-Resolution Mid-Atlantic Forecasting Ensemble (HME) is a federated effort to improve operational forecasts related to precipitation, convection and boundary layer evolution, and fire weather utilizing data and computing resources from a diverse group of cooperating institutions in order to create a mesoscale ensemble from independent members. Collaborating organizations involved in the project include universities, National Weather Service offices, and national laboratories, including the Savannah River National Laboratory (SRNL). The ensemble system is produced from an overlapping numerical weather prediction model domain and parameter subsets provided by each contributing member. The coordination, synthesis, and dissemination of the ensemble information are performed by the Renaissance Computing Institute (RENCI) at the University of North Carolina-Chapel Hill. This paper discusses background related to the HME effort, SRNL participation, and example results available from the RENCI website.

Buckley, R.; Werth, D.; Chiswell, S.; Etherton, B.

2011-05-10T23:59:59.000Z

229

The Response of an Ocean General Circulation Model to Surface Wind Stress Produced by an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

Two surface wind stress datasets for 1979–91, one based on observations and the other from an integration of the COLA atmospheric general circulation model (AGCM) with prescribed SST, are used to drive the GFDL ocean general circulation model. ...

Bohua Huang; Edwin K. Schneider

1995-10-01T23:59:59.000Z

230

A Finite-Element Model of the Atmospheric Boundary Layer Suitable for Use with Numerical Weather Prediction Models  

Science Conference Proceedings (OSTI)

We give a detailed description of an atmospheric boundary layer model capable of simulating the diurnal cycles of wind, temperature and humidity. The model includes a formulation of various physical processes (radiative effects, variation of soil ...

J. Mailhot; R. Benoit

1982-10-01T23:59:59.000Z

231

Predicting Tephra Dispersion with a Mesoscale Atmospheric Model and a Particle Fall Model: Application to Cerro Negro Volcano  

Science Conference Proceedings (OSTI)

Models of volcanic ash (tephra) fallout are increasingly used to assess volcanic hazards in advance of eruptions and in near–real time. These models often approximate the wind field using simplistic assumptions of the atmosphere that do not ...

Marc A. Byrne; Arlene G. Laing; Charles Connor

2007-02-01T23:59:59.000Z

232

Variability of the Thermohaline Circulation in an Ocean General Circulation Model Coupled to an Atmospheric Energy Balance Model  

Science Conference Proceedings (OSTI)

The variability of the ocean’s thermohaline circulation in an oceanic general circulation model (OGCM) coupled to a two-dimensional atmospheric energy balance model (EBM) is examined. The EBM calculates air temperatures by balancing heat fluxes, ...

David W. Pierce; K-Y. Kim; Tim P. Barnett

1996-05-01T23:59:59.000Z

233

A Combined Local and Nonlocal Closure Model for the Atmospheric Boundary Layer. Part I: Model Description and Testing  

Science Conference Proceedings (OSTI)

The modeling of the atmospheric boundary layer during convective conditions has long been a major source of uncertainty in the numerical modeling of meteorological conditions and air quality. Much of the difficulty stems from the large range of ...

Jonathan E. Pleim

2007-09-01T23:59:59.000Z

234

Impact of emissions, chemistry, and climate on atmospheric carbon monoxide : 100-year predictions from a global chemistry-climate model  

E-Print Network (OSTI)

The possible trends for atmospheric carbon monoxide in the next 100 yr have been illustrated using a coupled atmospheric chemistry and climate model driven by emissions predicted by a global economic development model. ...

Wang, Chien.; Prinn, Ronald G.

235

Snow Mass over North America: Observations and Results from the Second Phase of the Atmospheric Model Intercomparison Project  

Science Conference Proceedings (OSTI)

Eighteen global atmospheric general circulation models (AGCMs) participating in the second phase of the Atmospheric Model Intercomparison Project (AMIP-2) are evaluated for their ability to simulate the observed spatial and temporal variability ...

Allan Frei; Ross Brown; James A. Miller; David A. Robinson

2005-10-01T23:59:59.000Z

236

Simulation of the Tropical Oceans with an Ocean GCM Coupled to an Atmospheric Mixed-Layer Model  

Science Conference Proceedings (OSTI)

A reduced gravity, primitive equation, ocean general circulation model (GCM) is coupled to an advective atmospheric mixed-layer (AML) model to demonstrate the importance of a nonlocal atmospheric mixed-layer parameterization for a proper ...

Ragu Murtugudde; Richard Seager; Antonio Busalacchi

1996-08-01T23:59:59.000Z

237

Simulation of the Tropical Pacific Climate with a Coupled Ocean-Atmosphere General Circulation Model. Part II: Interannual Variability  

Science Conference Proceedings (OSTI)

Two multiyear simulations with a coupled ocean-atmosphere general circulation model (GCM)-totaling 45 years-are used to investigate interannual variability at the equator. The model consists of the UCLA global atmospheric GCM coupled to the GFDL ...

A. W. Robertson; C-C. Ma; M. Ghil; C. R. Mechoso

1995-05-01T23:59:59.000Z

238

Tropical Atlantic Decadal Oscillation and Its Potential Impact on the Equatorial Atmosphere–Ocean Dynamics: A Simple Model Study  

Science Conference Proceedings (OSTI)

Simple coupled atmosphere–ocean models are used to study the potential influence of the tropical Atlantic Ocean decadal oscillation on the equatorial Atlantic atmosphere–ocean dynamics. Perturbing the model tropical Atlantic at the extratropics (...

Sang-Ki Lee; Chunzai Wang

2008-01-01T23:59:59.000Z

239

The New GFDL Global Atmosphere and Land Model AM2–LM2: Evaluation with Prescribed SST Simulations  

Science Conference Proceedings (OSTI)

The configuration and performance of a new global atmosphere and land model for climate research developed at the Geophysical Fluid Dynamics Laboratory (GFDL) are presented. The atmosphere model, known as AM2, includes a new gridpoint dynamical ...

2004-12-01T23:59:59.000Z

240

Relations between Northward Ocean and Atmosphere Energy Transports in a Coupled Climate Model  

Science Conference Proceedings (OSTI)

The Third Hadley Centre Coupled Ocean–Atmosphere General Circulation Model (HadCM3) is used to analyze the relation between northward energy transports in the ocean and atmosphere at centennial time scales. In a transient water-hosing experiment, ...

Michael Vellinga; Peili Wu

2008-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Infrared Cooling in Cloudy Atmospheres: Precision of Grid Point Selection for Numerical Models  

Science Conference Proceedings (OSTI)

The infrared layer temperature change in a cloudy atmosphere normally shows warming at the base of the cloud and intense cooling at the top of the cloud. In a model that uses broad-band radiative transfer to calculate atmospheric temperature ...

L. P. Stearns

1983-07-01T23:59:59.000Z

242

Multiple Equilibria, Natural Variability, and Climate Transitions in an Idealized Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

An idealized coupled ocean–atmosphere is constructed to study climatic equilibria and variability. The model focuses on the role of large-scale fluid motions in the climate system. The atmospheric component is an eddy-resolving two-level global ...

R. Saravanan; James C. Mc Williams

1995-10-01T23:59:59.000Z

243

Modeling impacts of geomagnetic field variations on middle atmospheric ozone responses to solar proton  

E-Print Network (OSTI)

Modeling impacts of geomagnetic field variations on middle atmospheric ozone responses to solar charged particles of solar and cosmic origin. Therefore variations of the geomagnetic field occurring to the atmosphere under the consideration of different shielding properties of the geomagnetic field. The present

Wehrli, Bernhard

244

Toward a Multiscale Approach for Computational Atmospheric Modeling  

Science Conference Proceedings (OSTI)

Atmospheric motions are generally characterized by a wide range of multiple length and time scales, and a numerical method must use a fine grid to resolve such a wide range of scales. Furthermore, a very fine grid requires an extremely small time ...

Jahrul M. Alam

2011-12-01T23:59:59.000Z

245

An Update on Radiative Transfer Model Development at Atmospheric and Environmental Research, Inc.  

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

Update on Radiative Transfer Model Development at Update on Radiative Transfer Model Development at Atmospheric and Environmental Research, Inc. J. S. Delamere, S. A. Clough, E. J. Mlawer, Sid-Ahmed Boukabara, K. Cady-Pereira, and M. Shepard Atmospheric and Environmental Research, Inc. Lexington, Maine Introduction Over the last decade, a suite of radiative transfer models has been developed at Atmospheric and Environmental Research, Inc. (AER) with support from the Atmospheric and Radiation Measurement (ARM) Program. These models span the full spectral regime from the microwave to the ultraviolet, and range from monochromatic to band calculations. Each model combines the latest spectroscopic advancements with radiative transfer algorithms to efficiently compute radiances, fluxes, and cooling

246

Oxygen spectral line synthesis: 3D non-LTE with CO5BOLD hydrodynamical model atmospheres  

E-Print Network (OSTI)

In this work we present first results of our current project aimed at combining the 3D hydrodynamical stellar atmosphere approach with non-LTE (NLTE) spectral line synthesis for a number of key chemical species. We carried out a full 3D-NLTE spectrum synthesis of the oxygen IR 777 nm triplet, using a modified and improved version of our NLTE3D package to calculate departure coefficients for the atomic levels of oxygen in a CO5BOLD 3D hydrodynamical solar model atmosphere. Spectral line synthesis was subsequently performed with the Linfor 3D code. In agreement with previous studies, we find that the lines of the oxygen triplet produce deeper cores under NLTE conditions, due to the diminished line source function in the line forming region. This means that the solar oxygen IR 777 nm lines should be stronger in NLTE, leading to negative 3D NLTE-LTE abundance corrections. Qualitatively this result would support previous claims for a relatively low solar oxygen abundance. Finally, we outline several further steps ...

Prakapavicius, D; Kucinskas, A; Ludwig, H -G; Freytag, B; Caffau, E; Cayrel, R

2013-01-01T23:59:59.000Z

247

The Ocean–Land–Atmosphere Model: Optimization and Evaluation of Simulated Radiative Fluxes and Precipitation  

Science Conference Proceedings (OSTI)

This work continues the presentation and evaluation of the Ocean–Land–Atmosphere Model (OLAM), focusing on the model’s ability to represent radiation and precipitation. OLAM is a new, state-of-the-art earth system model, capable of user-specified ...

David Medvigy; Robert L. Walko; Martin J. Otte; Roni Avissar

2010-05-01T23:59:59.000Z

248

A Zonally Averaged, Coupled Ocean-Atmosphere Model for Paleoclimate Studies  

Science Conference Proceedings (OSTI)

A zonally averaged ocean model for the thermohaline circulation is coupled to a zonally averaged, one-layer energy balance model of the atmosphere to form a climate model for paleoclimate studies. The emphasis of the coupled model is on the ocean'...

Thomas F. Stocker; Lawrence A. Mysak; Daniel G. Wright

1992-08-01T23:59:59.000Z

249

Dynamic Models for the Subgrid-Scale Mixing of Reactants in Atmospheric Turbulent Reacting Flows  

Science Conference Proceedings (OSTI)

The effects of the subgrid scales on chemical transformations in large-eddy simulations of the convective atmospheric boundary layer (CBL) are investigated. Dynamic similarity subgrid-scale models are formulated and used to calculate the subgrid-...

Jean-François Vinuesa; Fernando Porté-Agel

2008-05-01T23:59:59.000Z

250

A Reduced Spectral Transform for the NCEP Seasonal Forecast Global Spectral Atmospheric Model  

Science Conference Proceedings (OSTI)

A reduced spectral transformation is applied to the NCEP atmospheric global spectral model for operational seasonal forecasts. The magnitude of the associated Legendre coefficient provides a basis for this new transformation, which is a simple ...

Hann-Ming Henry Juang

2004-04-01T23:59:59.000Z

251

A Dynamic and Thermodynamic Foundation for Modeling the Moist Atmosphere with Parameterized Microphysics  

Science Conference Proceedings (OSTI)

Moist convection is an exquisite yet powerful participant in the creation of weather on our planet. To facilitate numerical modeling of weather systems in a moist atmosphere, a direct and consistent application of dynamic and thermodynamic ...

Katsuyuki V. Ooyama

2001-08-01T23:59:59.000Z

252

Parameterization of Atmospheric Radiative Transfer. Part I: Validity of Simple Models  

Science Conference Proceedings (OSTI)

This paper outlines a radiation parameterization method for deriving broadband fluxes that is currently being implemented in a number of global and regional atmospheric models. The rationale for the use of the 2-stream method as a way of solving ...

Graeme L. Stephens; Philip M. Gabriel; Philip T. Partain

2001-11-01T23:59:59.000Z

253

A Model for the Turbulent Structure of the Stratocumulus–Topped Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

A multilevel ensemble-averaged model has been developed to study the cloud-topped atmospheric boundary layer (ABL). Turbulence closure is formulated by using an equation for the turbulent kinetic energy and either a diagnostic formulation of the ...

P. G. Duynkerke; A. G. M. Driedonks

1987-01-01T23:59:59.000Z

254

A Regional Ocean–Atmosphere Model for Eastern Pacific Climate: Toward Reducing Tropical Biases  

Science Conference Proceedings (OSTI)

The tropical Pacific Ocean is a climatically important region, home to El Niño and the Southern Oscillation. The simulation of its climate remains a challenge for global coupled ocean–atmosphere models, which suffer large biases especially in ...

Shang-Ping Xie; Toru Miyama; Yuqing Wang; Haiming Xu; Simon P. de Szoeke; R. Justin O. Small; Kelvin J. Richards; Takashi Mochizuki; Toshiyuki Awaji

2007-04-01T23:59:59.000Z

255

Coherent Structures in a Baroclinic Atmosphere. Part II: A Truncated Model Approach  

Science Conference Proceedings (OSTI)

Many recent studies have been devoted to atmospheric Patterns that persist beyond the synoptic time scale, such as those known as blocking events. In the present paper we explore the possibility that blocking patterns can be modeled with a local ...

Piero Malguzzi; Paola Malanotte Rizzoli

1985-12-01T23:59:59.000Z

256

Land Surface Hydrology Parameterization for Atmospheric General Circulation models Including Subgrid Scale Spatial Variability  

Science Conference Proceedings (OSTI)

Parameterizations are developed for the representation of subgrid hydrologic processes in atmospheric general circulation models. Reasonable a priori probability density functions of the spatial variability of soil moisture and of precipitation ...

D. Entekhabi; P. S. Eagleson

1989-08-01T23:59:59.000Z

257

Higher Order Turbulence Closure and Its Impact on Climate Simulations in the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

This paper describes climate simulations of the Community Atmosphere Model version 5 (CAM5) coupled with a higher-order turbulence closure, known as Cloud Layers Unified by Binormals (CLUBB). CLUBB is a unified parameterization of the planetary ...

Peter A. Bogenschutz; Andrew Gettelman; Hugh Morrison; Vincent E. Larson; Cheryl Craig; David P. Schanen

258

Three-Dimensional Linear Instability Modeling of the Cloud Level Venus Atmosphere  

Science Conference Proceedings (OSTI)

Based on the success of several 2-D (latitude, longitude) linear barotropic instability models at matching some of the observed characteristics of the cloud level, polar region of the Venus atmosphere, a more realistic, linear, 3-D (height, ...

Lee S. Elson

1989-12-01T23:59:59.000Z

259

Numerical Modeling of the Propagation Environment in the Atmospheric Boundary Layer over the Persian Gulf  

Science Conference Proceedings (OSTI)

Strong vertical gradients at the top of the atmospheric boundary layer affect the propagation of electromagnetic waves and can produce radar ducts. A three-dimensional, time-dependent, nonhydrostatic numerical model was used to simulate the ...

B. W. Atkinson; J-G. Li; R. S. Plant

2001-03-01T23:59:59.000Z

260

A Potential Predictability Study Conducted with an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

This paper describes a potential predictability study on the results of a 20.5 year simulation conducted with the Canadian Climate Centre (CCC) General Circulation Model (GCM). The CCC GCM is an atmosphere GCM with surface hydrology, soil ...

F. W. Zwiers

1987-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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.
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261

Higher-Order Turbulence Closure and Its Impact on Climate Simulations in the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

This paper describes climate simulations of the Community Atmosphere Model, version 5 (CAM5), coupled with a higher-order turbulence closure known as Cloud Layers Unified by Binormals (CLUBB). CLUBB is a unified parameterization of the planetary ...

Peter A. Bogenschutz; Andrew Gettelman; Hugh Morrison; Vincent E. Larson; Cheryl Craig; David P. Schanen

2013-12-01T23:59:59.000Z

262

Understanding El Niño in Ocean–Atmosphere General Circulation Models: Progress and Challenges  

Science Conference Proceedings (OSTI)

Determining how El Niño and its impacts may change over the next 10 to 100 years remains a difficult scientific challenge. Ocean–atmosphere coupled general circulation models (CGCMs) are routinely used both to analyze El Niño mechanisms and ...

Eric Guilyardi; Andrew Wittenberg; Alexey Fedorov; Mat Collins; Chunzai Wang; Antonietta Capotondi; Geert Jan van Oldenborgh; Tim Stockdale

2009-03-01T23:59:59.000Z

263

Axisymmetric Circulations Forced by Heat and Momentum Sources: A Simple Model Applicable to the Venus Atmosphere  

Science Conference Proceedings (OSTI)

The parametric behavior of an axially symmetric circulation induced by heat and momentum sources is analyzed in the context of a simple Boussinesq model. Implications for the Venus atmosphere are examined in the light of recent data.

Arthur Y. Hou

1984-12-01T23:59:59.000Z

264

Incorporation of CO2 Exchange Processes into a Multilayer Atmosphere–Soil–Vegetation Model  

Science Conference Proceedings (OSTI)

Carbon dioxide (CO2) exchange processes were incorporated into a multilayer atmosphere–soil–vegetation model known as SOLVEG, and its performance was examined using measurements obtained from a grassland site. It was also applied for the CO2 ...

Haruyasu Nagai

2005-10-01T23:59:59.000Z

265

A Three-Dimensional, Adaptive, Godunov-Type Model for Global Atmospheric Flows  

Science Conference Proceedings (OSTI)

In this paper a Godunov-type methodology is applied to three-dimensional global atmospheric modeling. Numerical issues are addressed regarding the formulation of the tracer advection problem, the application of dimensional splitting, and the ...

M. E. Hubbard; N. Nikiforakis

2003-08-01T23:59:59.000Z

266

The January and July Performance of the OSU Two-Level Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

A modified version of the two-level atmospheric general circulation model has been developed and used in the simulation of January and July global climates. The overall physical and numerical formulation of this Oregon State University (OSU) ...

Michael E. Schlesinger; W. Lawrence Gates

1980-09-01T23:59:59.000Z

267

Stability and Variability in a Coupled Ocean–Atmosphere Climate Model: Results of 100-year Simulations  

Science Conference Proceedings (OSTI)

Two 100-year seasonal simulators, one performed with a low resolution atmospheric general circulation model (GCM) coupled to a mixed-layer ocean formulation and the other made with the GCM forced by prescribed ocean conditions, are compared to ...

David D. Houghton; Robert G. Gallimore; Linda M. Keller

1991-06-01T23:59:59.000Z

268

Parameterization of PBL Processes in an Atmospheric General Circulation Model: Description and Preliminary Assessment  

Science Conference Proceedings (OSTI)

This paper presents the basic features of a newly developed planetary boundary layer (PBL) parameterization, and the performance assessment of a version of the University of California, Los Angeles (UCLA), Atmospheric General Circulation Model (...

Celal S. Konor; Gabriel Cazes Boezio; Carlos R. Mechoso; Akio Arakawa

2009-03-01T23:59:59.000Z

269

Tropical Cooling at the Last Glacial Maximum: An Atmosphere–Mixed Layer Ocean Model Simulation  

Science Conference Proceedings (OSTI)

The sensitivity of tropical temperature to glacial forcing is examined by using an atmosphere–mixed layer ocean (A–MLO) model to simulate the climate of the last glacial maximum (LGM) following specifications established by the Paleoclimate ...

Anthony J. Broccoli

2000-03-01T23:59:59.000Z

270

Numerical Experiments on Consistent Horizontal and Vertical Resolution for Atmospheric Models and Observing Systems  

Science Conference Proceedings (OSTI)

Simple numerical experiments are performed in order to determine the effects of inconsistent combinations of horizontal and vertical resolution in both atmospheric models and observing systems. In both cases, we find that inconsistent spatial ...

Michael S. Fox-Rabinovitz; Richard S. Lindzen

1993-01-01T23:59:59.000Z

271

Numerical Modeling of the Turbulent Fluxes of Chemically Reactive Trace Gases in the Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

Turbulent fluxes of chemically reactive trace gases in the neutral atmospheric boundary layer (ABL) were simulated with a one-dimensional, coupled diffusion-chemistry model. The effects of rapid chemical reactions were included with a suite of ...

W. Gao; M. L. Wesely

1994-07-01T23:59:59.000Z

272

Coupled Ocean–Atmosphere Dynamics in a Simple Midlatitude Climate Model  

Science Conference Proceedings (OSTI)

Midlatitude air–sea interactions are investigated by coupling a stochastically forced two-layer quasigeostrophic channel atmosphere to a simple ocean model. The stochastic forcing has a large-scale standing pattern to simulate the main modes of ...

David Ferreira; Claude Frankignoul; John Marshall

2001-09-01T23:59:59.000Z

273

Surface Turbulent Flux Formulation in Stable Conditions for Atmospheric Circulation Models  

Science Conference Proceedings (OSTI)

The forty-day Wangara data set is used to discuss the applicability of the traditional formulations for the surface fluxes for atmospheric circulation models. It is shown that, while in unstable conditions the surface layer relationships can be ...

Yves Delage

1985-01-01T23:59:59.000Z

274

Surface Temperature Calculation in Atmospheric Circulation Models with Coarse Resolution of the Boundary Layer  

Science Conference Proceedings (OSTI)

A parameterization of the surface nocturnal inversion of temperature is proposed to enable atmospheric circulation models to handle the surface energy budget without having to resolve the boundary layer. The scheme allows a wide range of vertical ...

Yves Delage

1986-02-01T23:59:59.000Z

275

Climate Simulation for 125 kyr BP with a Coupled Ocean–Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

The ECHAM-1 T21/LSG coupled ocean–atmosphere general circulation model (GCM) is used to simulate climatic conditions at the last interglacial maximum (Eemian, 125 kyr BP). The results reflect the expected surface temperature changes (with respect ...

Marisa Montoya; Hans von Storch; Thomas J. Crowley

2000-03-01T23:59:59.000Z

276

The Surface-Pressure Signature of Atmospheric Tides in Modern Climate Models  

Science Conference Proceedings (OSTI)

Although atmospheric tides driven by solar heating are readily detectable at the earth’s surface as variations in air pressure, their simulations in current coupled global climate models have not been fully examined. This work examines near-...

Curt Covey; Aiguo Dai; Dan Marsh; Richard S. Lindzen

2011-03-01T23:59:59.000Z

277

Free and Laterally Nudged Antarctic Climate of an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

Because many of the synoptic cyclones south of the 60°S parallel originate from 60°S and lower latitudes, nudging an atmospheric general circulation model (AGCM) with meteorological analyses at the periphery of the Antarctic region may be ...

Christophe Genthon; Gerhard Krinner; Emmanuel Cosme

2002-06-01T23:59:59.000Z

278

A Global Intercomparison of Modeled and Observed Land–Atmosphere Coupling  

Science Conference Proceedings (OSTI)

Land–atmosphere coupling strength or the degree to which land surface anomalies influence boundary layer development—and in extreme cases, rainfall—is arguably the single most fundamental criterion for evaluating hydrological model performance. ...

Craig R. Ferguson; Eric F. Wood; Raghuveer K. Vinukollu

2012-06-01T23:59:59.000Z

279

Very Narrow Band Model Calculations of Atmospheric Fluxes and Cooling Rates  

Science Conference Proceedings (OSTI)

A new very narrow band model (VNBM) approach has been developed and incorporated into the MODTRAN atmospheric transmittance–radiance code. The VNBM includes a computational spectral resolution of 1 cm?1, a single-line Voigt equivalent width ...

L. S. Bernstein; A. Berk; P. K. Acharya; D. C. Robertson; G. P. Anderson; J. H. Chetwynd; L. M. Kimball

1996-10-01T23:59:59.000Z

280

Trajectory Models for Heavy Particles in Atmospheric Turbulence: Comparison with Observations  

Science Conference Proceedings (OSTI)

The simplest “random flight” models for the paths of heavy particles in turbulence have been tested against previous observations of the deposition of glass beads from an elevated source in the atmospheric surface layer. For the bead sizes ...

John D. Wilson

2000-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Global Climate and Ocean Circulation on an Aquaplanet Ocean–Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

A low-resolution coupled ocean–atmosphere general circulation model (OAGCM) is used to study the characteristics of the large-scale ocean circulation and its climatic impacts in a series of global coupled aquaplanet experiments. Three ...

Robin S. Smith; Clotilde Dubois; Jochem Marotzke

2006-09-01T23:59:59.000Z

282

The Nature of Predictability Enhancement in a Low-Order Ocean-Atmosphere Model  

Science Conference Proceedings (OSTI)

A low-order moist general circulation model of the coupled ocean-atmosphere system is reexamined to determine the source of short-term predictability enhancement that occurs when an oceanic circulation is activated. The predictability enhancement ...

Jon M. Nese; Arthur J. Miller; John A. Dutton

1996-09-01T23:59:59.000Z

283

Comparison of Tropical Ocean–Atmosphere Fluxes with the NCAR Community Climate Model CCM3  

Science Conference Proceedings (OSTI)

The properties of the marine boundary layer produced by the National Center for Atmospheric Research (NCAR) Community Climate Model version 3 (CCM3) are compared with observations from two experiments in the central and western equatorial ...

William D. Collins; Junyi Wang; Jeffrey T. Kiehl; Guang J. Zhang; Daniel I. Cooper; William E. Eichinger

1997-12-01T23:59:59.000Z

284

Unstable and Damped Equatorial Modes in Simple Coupled Ocean-Atmosphere Models  

Science Conference Proceedings (OSTI)

Free equatorial modes for several simple coupled ocean-atmosphere models are determined. They are found to include unstable and damped modes of large zonal scale and long period. The influence of ocean thermo-dynamics on unstable modal behavior ...

Anthony C. Hirst

1986-03-01T23:59:59.000Z

285

Multiple Equilibria and Transitions in a Coupled Ocean–Atmosphere Box Model  

Science Conference Proceedings (OSTI)

A six-box model is employed as a prototype of the coupled Atlantic ocean–atmosphere system. Ice dynamics are excluded. Numerical integration of this system shows that different thermohaline circulation patterns are possible under the same forcing ...

Sergey V. Kravtsov; William K. Dewar

1998-02-01T23:59:59.000Z

286

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

287

Evaluation of Land-Atmosphere Interactions in Models of the North American Monsoon.  

E-Print Network (OSTI)

??Improving diurnal errors in surface-based heating processes in models might be a promising step towards improved seasonal simulation of the North American Monsoon (NAM). This… (more)

Kelly, Patrick

2008-01-01T23:59:59.000Z

288

Improvement of snowpack simulations in a regional climate model  

SciTech Connect

To improve simulations of regional-scale snow processes and related cold-season hydroclimate, the Community Land Model version 3 (CLM3), developed by the National Center for Atmospheric Research (NCAR), was coupled with the Pennsylvania State University/NCAR fifth-generation Mesoscale Model (MM5). CLM3 physically describes the mass and heat transfer within the snowpack using five snow layers that include liquid water and solid ice. The coupled MM5–CLM3 model performance was evaluated for the snowmelt season in the Columbia River Basin in the Pacific Northwestern United States using gridded temperature and precipitation observations, along with station observations. The results from MM5–CLM3 show a significant improvement in the SWE simulation, which has been underestimated in the original version of MM5 coupled with the Noah land-surface model. One important cause for the underestimated SWE in Noah is its unrealistic land-surface structure configuration where vegetation, snow and the topsoil layer are blended when snow is present. This study demonstrates the importance of the sheltering effects of the forest canopy on snow surface energy budgets, which is included in CLM3. Such effects are further seen in the simulations of surface air temperature and precipitation in regional weather and climate models such as MM5. In addition, the snow-season surface albedo overestimated by MM5–Noah is now more accurately predicted by MM5–CLM3 using a more realistic albedo algorithm that intensifies the solar radiation absorption on the land surface, reducing the strong near-surface cold bias in MM5–Noah. The cold bias is further alleviated due to a slower snowmelt rate in MM5–CLM3 during the early snowmelt stage, which is closer to observations than the comparable components of MM5–Noah. In addition, the over-predicted precipitation in the Pacific Northwest as shown in MM5–Noah is significantly decreased in MM5 CLM3 due to the lower evaporation resulting from the longer snow duration.

Jin, J.; Miller, N.L.

2011-01-10T23:59:59.000Z

289

Improved computer models support genetics research  

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

February Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and...

290

Improved computer models support genetics research  

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

Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and computational methods...

291

Reducing Climatology Bias in an Ocean–Atmosphere CGCM with Improved Coupling Physics  

Science Conference Proceedings (OSTI)

The cold tongue in the tropical Pacific extends too far west in most current ocean–atmosphere coupled GCMs (CGCMs). This bias also exists in the relatively high-resolution SINTEX-F CGCM despite its remarkable performance of simulating ENSO ...

Jing-Jia Luo; Sebastien Masson; Erich Roeckner; Gurvan Madec; Toshio Yamagata

2005-07-01T23:59:59.000Z

292

White dwarf atmosphere models with Ly-$\\alpha$ opacity in the analysis of the white dwarf cooling sequence of NGC 6397  

E-Print Network (OSTI)

We discuss the importance of pure hydrogen white dwarf atmosphere models with Ly-$\\rm \\alpha$ far red wing opacity in the analysis of the white dwarf cooling sequence of the globular cluster NGC 6397. Our recently improved atmosphere models account for the previously missing opacity from the Ly-$\\rm \\alpha$ hydrogen line broadened by collisions of the absorbing hydrogen atoms with molecular and atomic hydrogen. These models are the first that well reproduce the UV colors and spectral energy distributions of cool white dwarfs with $T_{\\rm eff}age of NGC 6397 derived from the white dwarf cooling sequence using ...

Kowalski, Piotr M

2007-01-01T23:59:59.000Z

293

Initiative to improve process representation in chemistry-climate models  

SciTech Connect

The Atmospheric Chemistry and Climate Initiative (AC&C) will address the current large uncertainties in our understanding of chemistry-climate interactions for short-lived atmospheric chemical constituents (e.g. aerosols, ozone, and methane). Understanding what controls the distribution of these species, how they affect climate, and how their distributions might change with a changing climate are important for air quality and climate forecasts. AC&C will address this issue in its first phase through a series of modeling exercises designed to test models’ ability to reproduce observed changes in these species distributions, to produce a set of coordinated forecasts for their future distribution, and to understand how processes are represented in different models. Observational databases will be used to test the models and to better understand processes represented in the models. This article describes the plans for this first phase of activities and seeks participation from the research community.

Doherty, Sarah J.; Rasch, Philip J.; Ravishankara, A.R.

2009-06-16T23:59:59.000Z

294

Motion and Evolution of Binary Tropical Cyclones in a Coupled Atmosphere–Ocean Numerical Model  

Science Conference Proceedings (OSTI)

The interaction of binary tropical cyclones (TC) is investigated using a coupled TC-ocean movable nested-grid model. The model consists of an eight-layer atmospheric model in the sigma coordinate system and a three-layer primitive equation ocean ...

Alexander I. Falkovich; Alexander P. Khain; Isaac Ginis

1995-05-01T23:59:59.000Z

295

An Improved Model for the Turbulent PBL  

Science Conference Proceedings (OSTI)

Second-order turbulence models of the Mellor and Yamada type have been widely used to simulate the planetary boundary layer (PBL). It is, however, known that these models have several deficiencies. For example, assuming the production of the ...

Y. Cheng; V. M. Canuto; A. M. Howard

2002-05-01T23:59:59.000Z

296

The Continuous Improvement Model| A K-12 Literacy Focus.  

E-Print Network (OSTI)

?? The purpose of the study was to determine if the eight steps of the Continuous Improvement Model (CIM) provided a framework to raise achievement… (more)

Brown, Jennifer V.

2014-01-01T23:59:59.000Z

297

Interhemispheric Asymmetry in the Transient Response of a Coupled Ocean–Atmosphere Model to a CO2 Forcing  

Science Conference Proceedings (OSTI)

Numerical experiments are carried out using a general circulation model of a coupled ocean-atmosphere system with idealized geography, exploring the transient response of climate to a rapid increase of atmospheric carbon dioxide. The ...

K. Bryan; S. Manabe; M. J. Spelman

1988-06-01T23:59:59.000Z

298

A Model for Solar Spectral Irradiance and Radiance at the Bottom and Top of a Cloudless Atmosphere  

Science Conference Proceedings (OSTI)

A simple model is presented that, in a cloud-free atmosphere, calculates solar spectral direct and diffuse irradiance and directional radiance at the surface, spectral absorption within the atmosphere and the upward reflected spectral irradiance ...

C. G. Justus; M. V. Paris

1985-03-01T23:59:59.000Z

299

The Steady-State Atmospheric Circulation Response to Climate Change–like Thermal Forcings in a Simple General Circulation Model  

Science Conference Proceedings (OSTI)

The steady-state extratropical atmospheric response to thermal forcing is investigated in a simple atmospheric general circulation model. The thermal forcings qualitatively mimic three key aspects of anthropogenic climate change: warming in the ...

Amy H. Butler; David W. J. Thompson; Ross Heikes

2010-07-01T23:59:59.000Z

300

An Analytical Model of Atmospheric Feedback and Global Temperature Change  

Science Conference Proceedings (OSTI)

An analytical model of the globally averaged surface temperature response to changes in radiative forcing induced by greenhouse gases is developed from a time-dependent version of the global energy budget. The model clarifies the role of feedback ...

John A. Dutton

1995-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Regional Models of the Atmosphere in Middle Latitudes  

Science Conference Proceedings (OSTI)

This review describes recent development in operational and research limited-area numerical weather prediction models in middle latitudes. The current skill of limited-area models is summarized through the use of conventional measures of ...

Richard A. Anthes

1983-06-01T23:59:59.000Z

302

Statistical Performance of Several Mesoscale Atmospheric Dispersion Models  

Science Conference Proceedings (OSTI)

Seventeen mesoscale dispersion models were statistically evaluated with data from krypton-85 emissions from the Savannah River Plant, Aiken, SC. Widely accepted statistical parameters were used for the statistical evaluation. The models were able ...

A. H. Weber; M. R. Buckner; J. H. Weber

1982-11-01T23:59:59.000Z

303

Atmospheric Dispersion Model Validation in Low Wind Conditions  

DOE Green Energy (OSTI)

and SCIPUFF models and under-prediction bias by the ALOHA model. The experiment parameters were for near field dispersion (less than 100 meters) in low wind speed conditions (less than 2 meters per second).

Patrick Sawyer

2007-11-01T23:59:59.000Z

304

Improved Model for Simulating Impedance Spectroscopy  

Science Conference Proceedings (OSTI)

... 26], the resistors and capacitors defined by ... on overly simple resistor-capacitor circuit models. ... the National Center for Super Computing Applications ...

1997-09-03T23:59:59.000Z

305

Influence of Mean Zonal Motion and Meridional Temperature Gradients on the Solar Semidiurnal Atmospheric Tide: A Revised Spectral Study with Improved Heating Rates  

Science Conference Proceedings (OSTI)

Calculations of the semidiurnal atmospheric tide at solstice using improved heating rates are presented. The heating rates for solar absorption by water vapor are based on a global water vapor distribution (Jenne, 1969, 1975; Jenne et al., 1974), ...

R. L. Walterscheid; J. G. DeVore; S. V. Venkateswaran

1980-02-01T23:59:59.000Z

306

Present-Day Atmospheric Simulations Using GISS ModelE: Comparison to In Situ, Satellite, and Reanalysis Data  

Science Conference Proceedings (OSTI)

A full description of the ModelE version of the Goddard Institute for Space Studies (GISS) atmospheric general circulation model (GCM) and results are presented for present-day climate simulations (ca. 1979). This version is a complete rewrite of ...

Gavin A. Schmidt; Reto Ruedy; James E. Hansen; Igor Aleinov; Nadine Bell; Mike Bauer; Susanne Bauer; Brian Cairns; Vittorio Canuto; Ye Cheng; Anthony Del Genio; Greg Faluvegi; Andrew D. Friend; Tim M. Hall; Yongyun Hu; Max Kelley; Nancy Y. Kiang; Dorothy Koch; Andy A. Lacis; Jean Lerner; Ken K. Lo; Ron L. Miller; Larissa Nazarenko; Valdar Oinas; Jan Perlwitz; Judith Perlwitz; David Rind; Anastasia Romanou; Gary L. Russell; Makiko Sato; Drew T. Shindell; Peter H. Stone; Shan Sun; Nick Tausnev; Duane Thresher; Mao-Sung Yao

2006-01-01T23:59:59.000Z

307

Prediction of Ice Crystal Number in Community Atmospheric Model (CAM3.0)  

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

Prediction of Ice Crystal Number in Community Atmospheric Model (CAM3.0) Prediction of Ice Crystal Number in Community Atmospheric Model (CAM3.0) Liu, Xiaohong Pacific Northwest National Laboratory Ghan, Steven Pacific Northwest National Laboratory Wang, M University of Michigan Penner, Joyce University of Michigan Category: Modeling A prognostic equation of ice crystal number concentrations is implemented in the Community Atmospheric Model (CAM3.0) with the aim to study the aerosol effects on climate through changing the ice cloud properties. The microphysical processes affecting the ice number concentration include ice nucleation, secondary production of crystals, and the conversion of ice to snow. For ice nucleation process, Liu and Penner (2005) parameterization of homogeneous nucleation of sulfate and heterogeneous immersion nucleation on

308

Improved diagnostic model for estimating wind energy  

DOE Green Energy (OSTI)

Because wind data are available only at scattered locations, a quantitative method is needed to estimate the wind resource at specific sites where wind energy generation may be economically feasible. This report describes a computer model that makes such estimates. The model uses standard weather reports and terrain heights in deriving wind estimates; the method of computation has been changed from what has been used previously. The performance of the current model is compared with that of the earlier version at three sites; estimates of wind energy at four new sites are also presented.

Endlich, R.M.; Lee, J.D.

1983-03-01T23:59:59.000Z

309

Monthly streamflow forecasting based on improved support vector machine model  

Science Conference Proceedings (OSTI)

To improve the performance of the support vector machine (SVM) model in predicting monthly streamflow, an improved SVM model with adaptive insensitive factor is proposed in this paper. Meanwhile, considering the influence of noise and the disadvantages ... Keywords: Adaptive insensitive factor, Artificial neural network, Chaos and phase-space reconstruction theory, Streamflow forecast, Support vector machine, Wavelet

Jun Guo; Jianzhong Zhou; Hui Qin; Qiang Zou; Qingqing Li

2011-09-01T23:59:59.000Z

310

Improving Ocean Model Initialization for Coupled Tropical Cyclone Forecast Models Using GODAE Nowcasts  

Science Conference Proceedings (OSTI)

To simulate tropical cyclone (TC) intensification, coupled ocean–atmosphere prediction models must realistically reproduce the magnitude and pattern of storm-forced sea surface temperature (SST) cooling. The potential for the ocean to support ...

G. R. Halliwell Jr.; L. K. Shay; S. D. Jacob; O. M. Smedstad; E. W. Uhlhorn

2008-07-01T23:59:59.000Z

311

Posters Single-Column Model for Atmospheric Radiation Measurement...  

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

Measurement Sites: Model Development and Sensitivity Test Q. Xu and M. Dong Cooperative Institute of Mesoscale Meteorological Studies University of Oklahoma Norman,...

312

Variability in a Mixed Layer Ocean Model Driven by Stochastic Atmospheric Forcing  

Science Conference Proceedings (OSTI)

A stochastic model of atmospheric surface conditions, developed from 30 years of data at Ocean Weather Station P in the northeast Pacific, is used to drive a mixed layer model of the upper mean. The spectral characteristics of anomalies in the ...

Michael A. Alexander; Cecile Penland

1996-10-01T23:59:59.000Z

313

A new wall-shear stress model for atmospheric boundary layer simulations  

Science Conference Proceedings (OSTI)

A new wall-shear stress model to be used as wall-boundary condition for Large Eddy Simulations of the Atmospheric Boundary Layer is proposed. The new model computes the wall shear stress and the vertical derivatives of the streamwise velocity ...

Marcus Hultmark; Marc Calaf; Marc B. Parlange

314

Atmospheric Responses of Gill-Type and Lindzen–Nigam Models to Global Warming  

Science Conference Proceedings (OSTI)

The equatorial Pacific atmosphere responds differently to global warming in the Gill-type and Lindzen–Nigam models. Under an assumption of no change in the zonal sea surface temperature (SST) gradient in the Gill-type model, the Walker circulation ...

Soon-Il An

2011-12-01T23:59:59.000Z

315

Stable Atmospheric Boundary Layers and Diurnal Cycles: Challenges for Weather and Climate Models  

Science Conference Proceedings (OSTI)

The representation of the atmospheric boundary layer is an important part of weather and climate models and impacts many applications such as air quality and wind energy. Over the years, the performance in modeling 2-m temperature and 10-m wind speed has ...

A. A. M. Holtslag; G. Svensson; P. Baas; S. Basu; B. Beare; A. C. M. Beljaars; F. C. Bosveld; J. Cuxart; J. Lindvall; G. J. Steeneveld; M. Tjernström; B. J. H. Van De Wiel

2013-11-01T23:59:59.000Z

316

Long-Term Variability in a Coupled Atmosphere–Biosphere Model  

Science Conference Proceedings (OSTI)

A fully coupled atmosphere–biosphere model, version 3 of the NCAR Community Climate Model (CCM3) and the Integrated Biosphere Simulator (IBIS), is used to illustrate how vegetation dynamics may be capable of producing long-term variability in the ...

Christine Delire; Jonathan A. Foley; Starley Thompson

2004-10-01T23:59:59.000Z

317

The Scripps Coupled Ocean–Atmosphere Regional (SCOAR) Model, with Applications in the Eastern Pacific Sector  

Science Conference Proceedings (OSTI)

A regional coupled ocean–atmosphere model is introduced. It is designed to admit the air–sea feedbacks arising in the presence of an oceanic mesoscale eddy field. It consists of the Regional Ocean Modeling System (ROMS) and the Regional Spectral ...

Hyodae Seo; Arthur J. Miller; John O. Roads

2007-02-01T23:59:59.000Z

318

Middle Atmosphere Climatologies from the Troposphere–Stratosphere Configuration of the UKMO’s Unified Model  

Science Conference Proceedings (OSTI)

A climatology of the middle atmosphere is determined from 11-yr integrations of the U.K. Meteorological Office Unified Model and compared with 18 years of satellite observations and 5 years of data assimilation fields. The model has an upper ...

Neal Butchart; John Austin

1998-09-01T23:59:59.000Z

319

Transformer Thermal Modeling: Improving Reliability Using Data Quality Control  

E-Print Network (OSTI)

1 Transformer Thermal Modeling: Improving Reliability Using Data Quality Control Daniel J. Tylavsky--Eventually all large transformers will be dynamically loaded using models updated regularly from field measured data. Models obtained from measured data give more accurate results than models based on transformer

320

Flux Parameterization over Land Surfaces for Atmospheric Models  

Science Conference Proceedings (OSTI)

In this paper a summary is given of observations and modeling efforts on surface fluxes, carried out at Cabauw in The Netherlands and during MESOGERS-84 in the south of France. Emphasis is put on those aspects that are important from a modeling ...

A. C. M. Beljaars; A. A. M. Holtslag

1991-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

EMSL: Science: Atmospheric Aerosol Systems  

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

Atmospheric Aerosol Systems Atmospheric Aerosol Systems atmospheric logo Nighttime enhancement of nitrogen-containing organic compounds, or NOC Observed nighttime enhancement of nitrogen-containing organic compounds, or NOC, showed evidence of being formed by reactions that transform carbonyls into imines. The Atmospheric Aerosol Systems Science Theme focuses on understanding the chemistry, physics and molecular-scale dynamics of aerosols for model parameterization to improve the accuracy of climate model simulations and develop a predictive understanding of climate. By elucidating the role of natural and anthropogenic regional and global climate forcing mechanisms, EMSL can provide DOE and others with the ability to develop cost-effective strategies to monitor, control and mitigate them.

322

A Surface Solar Radiation Model for Cloudy Atmospheres  

Science Conference Proceedings (OSTI)

A numerical solar radiation model based on standard meteorological data was revised for clouds using data from the GARP Atlantic Tropical Experiment (GATE). Climatic-mean transmittance functions were revised for low and convective clouds ...

Marshall A. Atwater; John T. Ball

1981-04-01T23:59:59.000Z

323

Singular Vector Analysis for Atmospheric Chemical Transport Models  

Science Conference Proceedings (OSTI)

The singular vectors of a chemical transport model are the directions of maximum perturbation growth over a finite time interval. They have proved useful for the estimation of error growth, the initialization of ensemble forecasts, and the ...

Wenyuan Liao; Adrian Sandu; Gregory R. Carmichael; Tianfeng Chai

2006-09-01T23:59:59.000Z

324

Research Opportunities from Emerging Atmospheric Observing and Modeling Capabilities  

Science Conference Proceedings (OSTI)

The Second Prospectus Development Team (PDT-2) of the U.S. Weather Research Program was charged with identifying research opportunities that are best matched to emerging operational and experimental measurement and modeling methods. The ...

Walter F. Dabberdt; Thomas W. Schlatter

1996-02-01T23:59:59.000Z

325

Extended-Range Atmospheric Prediction and the Lorenz Model  

Science Conference Proceedings (OSTI)

The physical basis for extended-range prediction is explored using the famous three-component Lorenz convection model, taken as a conceptual representation of the chaotic extratropical circulation, and extended by coupling to a linear oscillator ...

T. N. Palmer

1993-01-01T23:59:59.000Z

326

Air pollution forecasting by coupled atmosphere-fire model WRF and SFIRE with WRF-Chem  

E-Print Network (OSTI)

Atmospheric pollution regulations have emerged as a dominant obstacle to prescribed burns. Thus, forecasting the pollution caused by wildland fires has acquired high importance. WRF and SFIRE model wildland fire spread in a two-way interaction with the atmosphere. The surface heat flux from the fire causes strong updrafts, which in turn change the winds and affect the fire spread. Fire emissions, estimated from the burning organic matter, are inserted in every time step into WRF-Chem tracers at the lowest atmospheric layer. The buoyancy caused by the fire then naturally simulates plume dynamics, and the chemical transport in WRF-Chem provides a forecast of the pollution spread. We discuss the choice of wood burning models and compatible chemical transport models in WRF-Chem, and demonstrate the results on case studies.

Kochanski, Adam K; Mandel, Jan; Clements, Craig B

2013-01-01T23:59:59.000Z

327

An intercomparison of models used to simulate the short-range atmospheric dispersion of agricultural ammonia emissions  

Science Conference Proceedings (OSTI)

Ammonia emitted into the atmosphere from agricultural sources can have an impact on nearby sensitive ecosystems, either through elevated ambient concentrations or dry/wet deposition to vegetation and soil surfaces. Short-range atmospheric dispersion ... Keywords: Agriculture, Ammonia, Atmospheric dispersion model, Evaluation, Validation

Mark R. Theobald; Per LøFstrøM; John Walker; Helle V. Andersen; Poul Pedersen; Antonio Vallejo; Mark A. Sutton

2012-11-01T23:59:59.000Z

328

Measurement and modeling of shortwave irradiance components in cloud-free atmospheres  

SciTech Connect

Atmosphere scatters and absorbs incident solar radiation modifying its spectral content and decreasing its intensity at the surface. It is very useful to classify the earth-atmospheric solar radiation into several components--direct solar surface irradiance (E{sub direct}), diffuse-sky downward surface irradiance (E{sub diffuse}), total surface irradiance, and upwelling flux at the surface and at the top-of-the atmosphere. E{sub direct} depends only on the extinction properties of the atmosphere without regard to details of extinction, namely scattering or absorption; furthermore it can be accurately measured to high accuracy (0.3%) with the aid of an active cavity radiometer (ACR). E{sub diffuse} has relatively larger uncertainties both in its measurement using shaded pyranometers and in model estimates, owing to the difficulty in accurately characterizing pyranometers and in measuring model inputs such as surface reflectance, aerosol single scattering albedo, and phase function. Radiative transfer model simulations of the above surface radiation components in cloud-free skies using measured atmospheric properties show that while E{sub direct} estimates are closer to measurements, E{sub diffuse} is overestimated by an amount larger than the combined uncertainties in model inputs and measurements, illustrating a fundamental gap in the understanding of the magnitude of atmospheric absorption in cloud-free skies. The excess continuum type absorption required to reduce the E{sub diffuse} model overestimate ({approximately}3--8% absorptance) would significantly impact climate prediction and remote sensing. It is not clear at present what the source for this continuum absorption is. Here issues related to measurements and modeling of the surface irradiance components are discussed.

Halthore, R.N.

1999-08-04T23:59:59.000Z

329

Improved computer models support genetics research  

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

February » February » Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and computational methods provide insight into why genes are activated. February 8, 2013 When complete, these barriers will be a portion of the NMSSUP upgrade. This molecular structure depicts a yeast transfer ribonucleic acid (tRNA), which carries a single amino acid to the ribosome during protein construction. A combined experimental and computational approach, to better understand signaling pathways that lead to genetic mutations, is at the core of this research. Contact thumbnail of Brian Munsky, PhD Distinguished Postdoctoral Fellow Brian Munsky, PhD Information Services, Advanced Measurement Science

330

MODELING ATMOSPHERIC RELEASES OF TRITIUM FROM NUCLEAR INSTALLATIONS  

DOE Green Energy (OSTI)

Tritium source term analysis and the subsequent dispersion and consequence analyses supporting the safety documentation of Department of Energy nuclear facilities are especially sensitive to the applied software analysis methodology, input data and user assumptions. Three sequential areas in tritium accident analysis are examined in this study to illustrate where the analyst should exercise caution. Included are: (1) the development of a tritium oxide source term; (2) use of a full tritium dispersion model based on site-specific information to determine an appropriate deposition scaling factor for use in more simplified, broader modeling, and (3) derivation of a special tritium compound (STC) dose conversion factor for consequence analysis, consistent with the nature of the originating source material. It is recommended that unless supporting, defensible evidence is available to the contrary, the tritium release analyses should assume tritium oxide as the species released (or chemically transformed under accident's environment). Important exceptions include STC situations and laboratory-scale releases of hydrogen gas. In the modeling of the environmental transport, a full phenomenology model suggests that a deposition velocity of 0.5 cm/s is an appropriate value for environmental features of the Savannah River Site. This value is bounding for certain situations but non-conservative compared to the full model in others. Care should be exercised in choosing other factors such as the exposure time and the resuspension factor.

Okula, K

2007-01-17T23:59:59.000Z

331

Transient Response of the Hadley Centre Coupled Ocean-Atmosphere Model to Increasing Carbon Dioxide. Part III: Analysis of Global-Mean Response Using Simple Models  

Science Conference Proceedings (OSTI)

The roles of surface, atmospheric, and oceanic feedbacks in controlling the global-mean transient response of a coupled ocean-atmosphere general circulation model to increasing carbon dioxide are investigated. The analysis employs a four-box ...

J. M. Murphy

1995-03-01T23:59:59.000Z

332

Short-Term Oceanic Response Predicted by a Mixed Layer Model Forced with a Sector Atmospheric Model  

Science Conference Proceedings (OSTI)

A one-dimensional version of the Garwood bulk, oceanic mixed layer model is used to simulate the short- term response in a 60° sector. The atmospheric forcing is derived from a version of the UCLA general circulation model used by Sandgathe to ...

Russell L. Elsberry; Scott A. Sandgathe; Frank J. Winninghoff

1984-01-01T23:59:59.000Z

333

Modeling the Miocene Climatic Optimum. Part I: Land and Atmosphere  

Science Conference Proceedings (OSTI)

This study presents results from the Community Climate System Model 3 (CCSM3) forced with early to middle Miocene (~20–14 Ma) vegetation, topography, bathymetry, and modern CO2. A decrease in the meridional temperature gradient of 6.5°C and an ...

N. Herold; M. Huber; R. D. Müller

2011-12-01T23:59:59.000Z

334

WRF Model Experiments on the Antarctic Atmosphere in Winter  

Science Conference Proceedings (OSTI)

The standard and polar versions 3.1.1 of the Weather Research and Forecasting (WRF) model, both initialized by the 40-yr ECMWF Re-Analysis (ERA-40), were run in Antarctica for July 1998. Four different boundary layer–surface layer–radiation scheme ...

Esa-Matti Tastula; Timo Vihma

2011-04-01T23:59:59.000Z

335

The Ocean–Land–Atmosphere Model (OLAM). Part II: Formulation and Tests of the Nonhydrostatic Dynamic Core  

Science Conference Proceedings (OSTI)

The dynamic core of the Ocean–Land–Atmosphere Model (OLAM), which is a new global model that is partly based on the Regional Atmospheric Modeling System (RAMS), is described and tested. OLAM adopts many features of its predecessor, but its ...

Robert L. Walko; Roni Avissar

2008-11-01T23:59:59.000Z

336

Thermally driven escape from Pluto's atmosphere: A combined fluid/kinetic model  

E-Print Network (OSTI)

A combined fluid/kinetic model is developed to calculate thermally driven escape of N2 from Pluto's atmosphere for two solar heating conditions: no heating above 1450 km and solar minimum heating conditions. In the combined model, one-dimensional fluid equations are applied for the dense part of the atmosphere, while the exobase region is described by a kinetic model and calculated by the direct simulation Monte Carlo method. Fluid and kinetic parts of the model are iteratively solved in order to maintain constant total mass and energy fluxes through the simulation region. Although the atmosphere was found to be highly extended, with an exobase altitude at ~6000 km at solar minimum, the outflow remained subsonic and the escape rate was within a factor of two of the Jeans rate for the exobase temperatures determined. This picture is drastically different from recent predictions obtained solely using a fluid model which, in itself, requires assumptions about atmospheric density, flow velocity and energy flux ca...

Tucker, O J; Deighan, J I; Volkov, A N; Johnson, R E

2011-01-01T23:59:59.000Z

337

The mean climate of the Community Atmosphere Model (CAM4) in forced SST and fully coupled experiments  

SciTech Connect

The Community Atmosphere Model, version 4 (CAM4) was released as the atmosphere component of the Community Climate System Model, version 4 (CCSM4) and is described. The finite volume dynamical core available in CAM3 is now the default due to its superior transport and conservation properties. Deep convection parameterization changes include a dilute plume calculation of convective available potential energy (CAPE) and the introduction of a formulation for Convective Momentum Transport (CMT). For the cloud fraction an additional calculation is performed following macrophysical state updates that provides improved thermodynamic condistancy. A freeze-drying modification is further made to the cloud fraction calculation in very dry environments, such as arctic Winter, where cloud fractionand cloud water estimates were often inconsistant in CAM3. In CAM4 the finite volume dynamical core leads to a degradation in the excessive trade-wind simulation, but with an accompanying reduction in zonal stresses at higher latitudes. Plume dilution leads to a moister deep tropics alleviating much of the mid-tropospheric dry biases and reduces the persistant precipitation biases over the Arabian peninsular and the southern Indian ocean during the Indian Monsoon. CMT reduces much of the excessive trade-wind biases in eastern ocean basins. The freeze drying modification alleviates much of the high latitude, winter-time excessive cloud bias and improves the associated surface cloud-related energy budget, but the updated cloud macrophysical calculation generally leads to reduced cloud fraction and cloud forcing away from high latitudes. Although there are marginal improvements in time-averaged, large-scale hydrology there are signficant improvements in regional climate features such as the generation of tropical and propagation of stationary waves from the Pacific into mid-latitudes and in the seasonal frequency of Northern Hemisphere blocking events. A 1? versus 2? horizontal resolution of the finite volume 24 dynamical core exhibits signficiant improvements in model climate. Improvements in the fully coupled mean climate between CAM3 and CAM4 are also much more signficant than in forced Sea Surface Temperature (SST) simulations. Furthermore, improvements in the transient characteristics ofthe model climate, documented elsewhere, are substantial.

Neale, Richard; Richter, Jadwiga; Park, Sungsu; Lauritzen, P. H.; Vavrus, Steven J.; Rasch, Philip J.; Zhang, Minghua

2013-07-15T23:59:59.000Z

338

Evaluating the Carbon Cycle of a Coupled Atmosphere-Biosphere Model  

SciTech Connect

We investigate how well a coupled biosphere-atmosphere model, CCM3-IBIS, can simulate the functioning of the terrestrial biosphere and the carbon cycling through it. The simulated climate is compared to observations, while the vegetation cover and the carbon cycle are compared to an offline version of the biosphere model IBIS forced with observed climatic variables. The simulated climate presents some local biases that strongly affect the vegetation (e.g., a misrepresentation of the African monsoon). Compared to the offline model, the coupled model simulates well the globally averaged carbon fluxes and vegetation pools. The zonal mean carbon fluxes and the zonal mean seasonal cycle are also well represented except between 0{sup o} and 20{sup o}N due to the misrepresentation of the African monsoon. These results suggest that, despite regional biases in climate and ecosystem simulations, this coupled atmosphere-biosphere model can be used to explore geographic and temporal variations in the global carbon cycle.

Delire, C; Foley, J A; Thompson, S

2002-08-21T23:59:59.000Z

339

Real-time modeling of complex atmospheric releases in urban areas  

Science Conference Proceedings (OSTI)

If a nuclear installation in or near an urban area has a venting, fire, or explosion, airborne radioactivity becomes the major concern. Dispersion models are the immediate tool for estimating the dose and contamination. Responses in urban areas depend on knowledge of the amount of the release, representative meteorological data, and the ability of the dispersion model to simulate the complex flows as modified by terrain or local wind conditions. A centralized dispersion modeling system can produce realistic assessments of radiological accidents anywhere in a country within several minutes if it is computer-automated. The system requires source-term, terrain, mapping and dose-factor databases, real-time meteorological data acquisition, three-dimensional atmospheric transport and dispersion models, and experienced staff. Experience with past responses in urban areas by the Atmospheric Release Advisory Capability (ARAC) program at Lawrence Livermore National Laboratory illustrate the challenges for three-dimensional dispersion models.

Baskett, R.L. [EG and G Energy Measurements, Inc., Pleasanton, CA (United States); Ellis, J.S.; Sullivan, T.J. [Lawrence Livermore National Lab., CA (United States)

1994-08-01T23:59:59.000Z

340

BISON Enhanced with Improved Models for Cladding and Coolant Channels |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Enhanced with Improved Models for Cladding and Coolant Enhanced with Improved Models for Cladding and Coolant Channels BISON Enhanced with Improved Models for Cladding and Coolant Channels January 29, 2013 - 10:54am Addthis Pin-scale Code Development Development of BISON for the engineering-scale simulation of nuclear fuel performance continued. Enhancements during this quarter include implementation of a nonlinear material model for Zircaloy cladding that simultaneously combines the phenomena of plasticity, thermal creep, and irradiation creep; implementation of a complete set of material properties and a creep model for stainless steel cladding; and modification of the coolant sub-channel model to better support simulations of loss-of- coolant-accidents. BISON simulations are being compared to relevant empirical fuel pin data

Note: This page contains sample records for the topic "improving atmospheric models" 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

ORNL researchers improve soil carbon cycling models | ornl.gov  

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

researchers improve soil carbon cycling models researchers improve soil carbon cycling models January 01, 2013 ORNL's new carbon cycling model could help scientists understand the role of soil microbes (MBC) in climate change by tracking extracellular enzymes (ENZ) that break down carbon-rich soil materials (SOC) into forms that microbes can respire (DOC). A more robust model of the soil carbon cycle developed at Oak Ridge National Laboratory (ORNL) improves understanding of carbon residence time in soils and enables scientists to make more accurate climate predictions. The model does a better job than previous models of accounting for how microbes in the soil break down carbon-rich materials and release carbon dioxide. "Soil is a big reservoir of carbon," said co-author Melanie Mayes of the Environmental Sciences Division and the Climate Change Science

342

An Improved Modeling Scheme for Freezing Precipitation Forecasts  

Science Conference Proceedings (OSTI)

To improve forecasts of various weather elements (snow, rain, and freezing precipitation) in numerical weather prediction models, a new mixed-phase cloud scheme has been developed. The scheme is based on a single prognostic equation for total ...

André Tremblay; Anna Glazer

2000-05-01T23:59:59.000Z

343

Perturbation Correction to the Two-Stream Model Applied to the Earth’s Atmosphere  

Science Conference Proceedings (OSTI)

In the interior of a clear, cloudless, and optically thin atmosphere (?0 ? 0.8) the predictions of even the most accurate two-stream models can significantly deviate from exact calculations. A perturbation correction to the differential form of a ...

N. T. O’Neill

1997-01-01T23:59:59.000Z

344

Subduction over the Southern Indian Ocean in a High-Resolution Atmosphere–Ocean Coupled Model  

Science Conference Proceedings (OSTI)

This study examines the subduction of the Subantarctic Mode Water in the Indian Ocean in an ocean–atmosphere coupled model in which the ocean component is eddy permitting. The purpose is to assess how sensitive the simulated mode water is to the ...

Mei-Man Lee; A. J. George Nurser; I. Stevens; Jean-Baptiste Sallée

2011-08-01T23:59:59.000Z

345

The National Center for Atmospheric Research Community Climate Model: CCM3  

Science Conference Proceedings (OSTI)

The latest version of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3) is described. The changes in both physical and dynamical formulation from CCM2 to CCM3 are presented. The major differences in CCM3 compared ...

J. T. Kiehl; J. J. Hack; G. B. Bonan; B. A. Boville; D. L. Williamson; P. J. Rasch

1998-06-01T23:59:59.000Z

346

Stratified Turbulence in the Atmosphere and Oceans: A New Subgrid Model  

Science Conference Proceedings (OSTI)

Turbulence in a stratified medium is studied with emphasis on stable stratification, as it occurs in the atmosphere and oceans, and on the construction of a subgrid model (SGS) for use in large eddy simulation (LES). The two basic assumptions of ...

V. M. Canuto; F. Minotti

1993-07-01T23:59:59.000Z

347

Bayesian Modelling Volatility of Growth Rate in Atmospheric Carbon Dioxide Concentrations  

Science Conference Proceedings (OSTI)

Atmospheric gases, such as carbon dioxide, ozone, methane, nitrous oxide, and etc., create a natural greenhouse effect and cause climate change. Therefore, modelling behavior of these gases could help policy makers to control greenhouse effects. In a ... Keywords: Stochastic volatility, Smooth transition autoregressive, Markov chain Monte Carlo, methods, Bayesian, ARCH, GARCH

Esmail Amiri

2009-12-01T23:59:59.000Z

348

Verification of an Atmospheric Mixed-Layer Model for a Coastal Region  

Science Conference Proceedings (OSTI)

An evaluation of the ability of an integrated (slab) marine atmospheric boundary-layer (MABL) model to predict changes in the inversion and mixed-layer temperature and humidity using data from the Los Angeles-San Diego Basin is described. The ...

K. L. Davidson; C. W. Fairall; P. Jones Boyle; G. E. Schacher

1984-04-01T23:59:59.000Z

349

Diagnosing Land–Atmosphere Interaction from a Regional Climate Model Simulation over West Africa  

Science Conference Proceedings (OSTI)

Land–atmosphere interaction at climatological time scales in a large area that includes the West African Sahel has been explicitly explored in a regional climate model (RegCM) simulation using a range of diagnostics. First, areas and seasons of ...

Bart J. J. M. van den Hurk; Erik van Meijgaard

2010-04-01T23:59:59.000Z

350

Exploratory High-Resolution Climate Simulations using the Community Atmosphere Model (CAM)  

Science Conference Proceedings (OSTI)

Extended, high-resolution (0.23°lat ×0.31°lon) simulations with Community Atmosphere Model versions 4 and 5 (CAM4 and CAM5) are examined and compared with results from climate simulations conducted at a more typical resolution of 0.9°lat ×1.25°...

Julio T. Bacmeister; Michael F. Wehner; Richard B. Neale; Andrew Gettelman; Cecile Hannay; Peter H. Lauritzen; Julie M. Caron; John E. Truesdale

351

Improved Formulations for Air-Surface Exchanges Related to National Security Needs: Dry Deposition Models  

Science Conference Proceedings (OSTI)

The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and. 4) development of dry deposition formulations applicable to urban areas. Also to improve dry deposition modeling capabilities, atmospheric dispersion models in which the dry deposition formulations are imbedded need better source-term plume initialization and improved in-plume treatment of particle growth processes. Dry deposition formulations used in current models are largely inapplicable to the complex urban environment. An improved capability is urgently needed to provide surface-specific information to assess local exposure hazard levels in both urban and non-urban areas on roads, buildings, crops, rivers, etc. A model improvement plan is developed with a near-term and far-term component. Despite some conceptual limitations, the current formulations for particle deposition based on a resistance approach have proven to provide reasonable dry deposition simulations. For many models with inadequate dry deposition formulations, adding or improving a resistance approach will be the desirable near-term update. Resistance models however are inapplicable aerodynamically very rough surfaces such as urban areas. In the longer term an improved parameterization of dry deposition needs to be developed that will be applicable to all surfaces, and in particular urban surfaces.

Droppo, James G.

2006-07-01T23:59:59.000Z

352

Improved Model Output Statistics Forecasts through Model Consensus  

Science Conference Proceedings (OSTI)

Consensus forecasts are computed by averaging model output statistics (MOS) forecasts based on the limited-area fine-mesh (LFM) model and the nested grid model (NGM) for the three-year period 1990–92. The test consists of four weather elements (...

Robert L. Vislocky; J. Michael Fritsch

1995-07-01T23:59:59.000Z

353

Assessment of methods for creating a national building statistics database for atmospheric dispersion modeling  

SciTech Connect

Mesoscale meteorological codes and transport and dispersion models are increasingly being applied in urban areas. Representing urban terrain characteristics in these models is critical for accurate predictions of air flow, heating and cooling, and airborne contaminant concentrations in cities. A key component of urban terrain characterization is the description of building morphology (e.g., height, plan area, frontal area) and derived properties (e.g., roughness length). Methods to determine building morphological statistics range from manual field surveys to automated processing of digital building databases. In order to improve the quality and consistency of mesoscale meteorological and atmospheric dispersion modeling, a national dataset of building morphological statistics is needed. Currently, due to the expense and logistics of conducting detailed field surveys, building statistics have been derived for only small sections of a few cities. In most other cities, modeling projects rely on building statistics estimated using intuition and best guesses. There has been increasing emphasis in recent years to derive building statistics using digital building data or other data sources as a proxy for those data. Although there is a current expansion in public and private sector development of digital building data, at present there is insufficient data to derive a national building statistics database using automated analysis tools. Too many cities lack digital data on building footprints and heights and many of the cities having such data do so for only small areas. Due to the lack of sufficient digital building data, other datasets are used to estimate building statistics. Land use often serves as means to provide building statistics for a model domain, but the strength and consistency of the relationship between land use and building morphology is largely uncertain. In this paper, we investigate whether building statistics can be correlated to the underlying land use. If a reasonable correlation exists, then a national building statistics database could be created since land use is available for the entire U.S. Digital datasets of building footprint and height information have been obtained, validated and analyzed for eight western U.S. cities covering areas ranging from 6 km{sup 2} to 1653 km{sup 2}. Building morphological statistics (including mean and standard deviation of building height, plan area fraction and density, rooftop area density, frontal area index and density, building-to-plan area ratio, complete aspect ratio, height-to-width ratio, roughness length, displacement height, and sky view factor) have been computed for each city at 250-m resolution and are being correlated to underlying land use type. This paper will summarize the building statistics from the eight cites focusing on the variability within each city and between cities as a function of land use.

Velugubantla, S. P. (Srinivas, P.); Burian, S. J. (Steven J.); Brown, M. J. (Michael J.); McKinnon, A. T. (Andrew T.); McPherson, T. N. (Timothy N.); Han, W. S. (Woo Suk)

2004-01-01T23:59:59.000Z

354

Agriculture model development to improve performance of the Community Land  

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

Agriculture model development to improve performance of the Community Land Agriculture model development to improve performance of the Community Land Model April 3, 2013 The important relationships between climate change and agriculture are uncertain, particularly the feedbacks related to the carbon cycle. Nevertheless, vegetation models have not yet considered the full impacts of management practices and nitrogen feedbacks on the carbon cycle. We are working to meet this need. We have integrated three crop types (corn, soybean, and spring wheat) into the Community Land Model (CLM). In developing the agriculture version of CLM, we added plant processes related to management practices and nitrogen cycling. A manuscript documenting our changes to CLM has been accepted for publication in Geoscientific Model Development Discussions ("Modeling

355

Atmospheric Motion Vectors from Model Simulations. Part I: Methods and Characterisation as Single-Level Estimates of Wind  

Science Conference Proceedings (OSTI)

The objective of this study is to improve the characterization of satellite-derived Atmospheric Motion Vectors (AMVs) and their errors to guide developments in the use of AMVs in Numerical Weather Prediction. AMVs tend to exhibit considerable ...

Niels Bormann; Angeles Hernandez-Carrascal; Régis Borde; Hans-Joachim Lutz; Jason A. Otkin; Steve Wanzong

356

Does increasing model stratospheric resolution improve extended range forecast skill?  

E-Print Network (OSTI)

Does increasing model stratospheric resolution improve extended range forecast skill? Greg Roff,1 forecast skill at high Southern latitudes is explored. Ensemble forecasts are made for two model configurations that differ only in vertical resolution above 100 hPa. An ensemble of twelve 30day forecasts

357

Increasing NOAA's computational capacity to improve global forecast modeling  

E-Print Network (OSTI)

1 Increasing NOAA's computational capacity to improve global forecast modeling A NOAA of the NWS's forecast products, even its regional forecast products, are constrained by the limitations of NOAA's global forecast model. Unfortunately, our global forecasts are less accurate than those from

Hamill, Tom

358

Geothermal: Sponsored by OSTI -- Improving Convection Parameterization...  

Office of Scientific and Technical Information (OSTI)

Improving Convection Parameterization Using ARM Observations and NCAR Community Atmosphere Model Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin...

359

An Improved Simple Chilled Water Cooling Coil Model  

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

An Improved Simple Chilled Water Cooling Coil Model An Improved Simple Chilled Water Cooling Coil Model Title An Improved Simple Chilled Water Cooling Coil Model Publication Type Conference Paper LBNL Report Number LBNL-6031E Year of Publication 2012 Authors Wang, Liping, Philip Haves, and Walter F. Buhl Conference Name SimBuild 2012 IBPSA Conference Date Published 08/2012 Abstract The accurate prediction of cooling and dehumidification coil performance is important in model-based fault detection and in the prediction of HVAC system energy consumption for support of both design and operations. It is frequently desirable to use a simple cooling coil model that does not require detailed specification of coil geometry and material properties. The approach adopted is to match the overall UA of the coil to the rating conditions and to estimate the air-side and water-side components of the UA using correlations developed by Holmes (1982). This approach requires some geometrical information about the coil and the paper investigates the sensitivity of the overall performance prediction to uncertainties in this information, including assuming a fixed ratio of air-side to water-side UA at the rating condition. Finally, simulation results from different coil models are compared, and experimental data are used to validate the improved cooling coil model.

360

The Mean Climate of the Community Atmosphere Model (CAM4) in Forced SST and Fully Coupled Experiments  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model, version 4 (CAM4), was released as part of the Community Climate System Model, version 4 (CCSM4). The finite volume (FV) dynamical core is now the default because of its superior transport and conservation ...

Richard B. Neale; Jadwiga Richter; Sungsu Park; Peter H. Lauritzen; Stephen J. Vavrus; Philip J. Rasch; Minghua Zhang

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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361

Modeling Global and Regional Net Primary Production under Elevated Atmospheric CO2: On a Potential Source of Uncertainty  

Science Conference Proceedings (OSTI)

Terrestrial ecosystem models are built, among several reasons, to explore how the Earth’s biosphere responds to climate change and to the projected continual increase of atmospheric CO2 concentration. Many of these models adopt the Farquhar et ...

Mustapha El Maayar; Navin Ramankutty; Christopher J. Kucharik

2006-01-01T23:59:59.000Z

362

Simulations of the Atmospheric General Circulation Using a Cloud-Resolving Model as a Superparameterization of Physical Processes  

Science Conference Proceedings (OSTI)

Traditionally, the effects of clouds in GCMs have been represented by semiempirical parameterizations. Recently, a cloud-resolving model (CRM) was embedded into each grid column of a realistic GCM, the NCAR Community Atmosphere Model (CAM), to ...

Marat Khairoutdinov; David Randall; Charlotte DeMott

2005-07-01T23:59:59.000Z

363

Grid Adaption and Its Effect on Entrainment in an E–l Model of the Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

A one-dimensional numerical model KOLUM is introduced that demonstrates the use of continuous dynamic grid adaption in modeling the atmospheric boundary layer. The entrainment rates of KOLUM are compared against recent calibrations for smoke ...

Brian H. Fiedler

2002-03-01T23:59:59.000Z

364

Relationships between Net Radiation at the Surface and the Top of the Atmosphere Derived from a General Circulation Model  

Science Conference Proceedings (OSTI)

The relationships between the net radiation at the surface and the top of the atmosphere in the UCLA general circulation model are investigated. These suggest that it may be possible to formulate statistical models from limited observations ...

Bryan C. Weare

1989-02-01T23:59:59.000Z

365

Impact of Climate Drift on Twenty-First-Century Projection in a Coupled Atmospheric–Ocean General Circulation Model  

Science Conference Proceedings (OSTI)

Reducing climate drift in coupled atmosphere–ocean general circulation models (AOGCMs) usually requires 1000–2000 years of spinup, which has not been practical for every modeling group to do. For the purpose of evaluating the impact of climate ...

Mao-Chang Liang; Li-Ching Lin; Ka-Kit Tung; Yuk L. Yung; Shan Sun

2013-10-01T23:59:59.000Z

366

A Model Study of the Stably Stratified Steady-State Atmospheric Boundary Layer over a Slightly Inclined Terrain  

Science Conference Proceedings (OSTI)

A simple, steady-state, numerical model is used to examine the Rossby-number similarity theory of the atmospheric boundary layer over a slightly inclined terrain. The model confirms the similarity predictions. The slope-influenced universal ...

Zbigniew Sorbjan

1984-06-01T23:59:59.000Z

367

Dynamically Consistent Formulations in Meteorological and Air Quality Models for Multiscale Atmospheric Studies. Part II: Mass Conservation Issues  

Science Conference Proceedings (OSTI)

Eulerian air quality models that require gridded meteorological inputs have to adapt to recent advances in meteorological models for fully compressible atmosphere. When the input meteorological data are recast with a robust fully compressible ...

Daewon W. Byun

1999-11-01T23:59:59.000Z

368

Analysis of Passive Tracer Transport as Modeled by an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

Tracers without feedback on the atmosphere are used to probe tropospheric transport. Such passive tracers are considered for two important anthropogenic sources, Europe and eastern North America. The linearity of passive tracer continuity allows ...

Mark Holzer

1999-06-01T23:59:59.000Z

369

Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754  

DOE Green Energy (OSTI)

RX J1856.5-3754 is one of the brightest nearby isolated neutron stars, and considerable observational resources have been devoted to it. However, current models are unable to satisfactorily explain the data. We show that our latest models of a thin, magnetic, partially ionized hydrogen atmosphere on top of a condensed surface can fit the entire spectrum, from X-rays to optical, of RX J1856.5-3754, within the uncertainties. In our simplest model, the best-fit parameters are an interstellar column density N{sub H} {approx} 1 x 10{sup 20} cm{sup -2} and an emitting area with R{sup {infinity}} {approx} 17 km (assuming a distance to RX J1856.5-3754 of 140 pc), temperature T{sup {infinity}} {approx} 4.3 x 10{sup 5} K, gravitational redshift z{sub g} {approx} 0.22, atmospheric hydrogen column y{sub H} {approx} 1 g cm{sup -2}, and magnetic field B {approx} (3-4) x 10{sup 12} G; the values for the temperature and magnetic field indicate an effective average over the surface. We also calculate a more realistic model, which accounts for magnetic field and temperature variations over the neutron star surface as well as general relativistic effects, to determine pulsations; we find there exist viewing geometries that produce pulsations near the currently observed limits. The origin of the thin atmospheres required to fit the data is an important question, and we briefly discuss mechanisms for producing these atmospheres. Our model thus represents the most self-consistent picture to date for explaining all the observations of RX J1856.5-3754.

Ho, Wynn C.G.; /MIT, MKI /KIPAC, Menlo Park; Kaplan, David L.; /MIT, MKI; Chang, Philip; /UC, Berkeley, Astron. Dept. /UC, Santa Barbara; van Adelsberg, Matthew; /Cornell; Potekhin, Alexander Y.; /Cornell U., Astron. Dept. /Ioffe Phys. Tech. Inst.

2006-12-08T23:59:59.000Z

370

Land Surface Model Development for the GISS GCM: Effects of Improved Canopy Physiology on Simulated Climate  

Science Conference Proceedings (OSTI)

A new physiology-based model of canopy stomatal conductance and photosynthesis is described and included in the latest version of the Goddard Institute for Space Studies (GISS) GCM, ModelE1. The submodel includes responses to atmospheric humidity ...

Andrew D. Friend; Nancy Y. Kiang

2005-08-01T23:59:59.000Z

371

Combined Stellar Structure and Atmosphere Models: Exploratory Results for Wolf-Rayet Stars  

E-Print Network (OSTI)

In this paper we present Complete Stellar models (CoStar) for massive stars, which treat the stellar interior and atmosphere, including its wind. Particular emphasis is given to Wolf-Rayet stars. We address the question of the effective temperatures of WNE and WC stars. Our first results show a satisfactory agreement between the CoStar models and the simple temperature correction method applied by Schaller et al. (1992). An analyses of the subphotospheric structure of the WR star models shows the importance of metal opacity. This may be essential for understanding the driving mechanism of Wolf-Rayet winds.

D. Schaerer; A. de Koter; W. Schmutz

1994-10-14T23:59:59.000Z

372

DOE Workshop; Pan-Gass Conference on the Representation of Atmospheric Processes in Weather and Climate Models  

SciTech Connect

This is the first meeting of the whole new GEWEX (Global Energy and Water Cycle Experiment) Atmospheric System Study (GASS) project that has been formed from the merger of the GEWEX Cloud System Study (GCSS) Project and the GEWEX Atmospheric Boundary Layer Studies (GABLS). As such, this meeting will play a major role in energizing GEWEX work in the area of atmospheric parameterizations of clouds, convection, stable boundary layers, and aerosol-cloud interactions for the numerical models used for weather and climate projections at both global and regional scales. The representation of these processes in models is crucial to GEWEX goals of improved prediction of the energy and water cycles at both weather and climate timescales. This proposal seeks funds to be used to cover incidental and travel expenses for U.S.-based graduate students and early career scientists (i.e., within 5 years of receiving their highest degree). We anticipate using DOE funding to support 5-10 people. We will advertise the availability of these funds by providing a box to check for interested participants on the online workshop registration form. We will also send a note to our participants' mailing lists reminding them that the funds are available and asking senior scientists to encourage their more junior colleagues to participate. All meeting participants are encouraged to submit abstracts for oral or poster presentations. The science organizing committee (see below) will base funding decisions on the relevance and quality of these abstracts, with preference given to under-represented populations (especially women and minorities) and to early career scientists being actively mentored at the meeting (e.g. students or postdocs attending the meeting with their advisor).

Morrison, PI Hugh

2012-09-21T23:59:59.000Z

373

Single-Column Modeling C. J. Walcek Atmospheric Sciences Research Center  

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

C. J. Walcek C. J. Walcek Atmospheric Sciences Research Center State University of New York Albany, New York Introduction intense mid latitude cyclone developed and traversed this domain, allowing one to investigate cloud cover under a wide variety of meteorological environments. Large-scale numerical models of the atmosphere approximate the heterogeneous or subgrid-scale nature of cloudiness by assuming that a fraction of each grid area is occupied by clouds. This cloud cover fraction is used to apportion cloud effects into a "grid-averaged" forcing within areas that contain a mixture of clear and cloudy regions. Most models of tropospheric dynamics assume that the fractional cloud coverage is determined by the grid- averaged relative humidity, stability, or resolvable-scale

374

Atmospheric transmission model for a solar beam propagating between a heliostat and a receiver  

Science Conference Proceedings (OSTI)

Formulae are presented that provide estimates of the transmittance for a solar beam propagating between a heliostat and a central receiver. These formulae are wavelength independent, functional fits to the tabulated data of Vittitoe and Biggs, which in turn are from numerical integrations of spectral transmittance data calculated with the aid of the computer code LOWTRAN 3. The formulae allow for interpolation and extrapolation, and they have a form characteristic of atmospheric transmission models. The transmittance model contains five explicit physical variables (the site elevation H, the atmospheric water vapor density rho, the scattering coefficient ..beta.., the tower height h, and the slant range R) and three implicit variables (the season of the year, the climatic region, and the site elevation H) because rho and ..beta.. are dependent on these three variables.

Pitman, C.L.; Vant-Hull, L.L.

1982-01-01T23:59:59.000Z

375

Estimating Bacteria Emissions from Inversion of Atmospheric Transport: Sensitivity to Modelled Particle Characteristics  

SciTech Connect

Model-simulated transport of atmospheric trace components can be combined with observed concentrations to obtain estimates of ground-based sources using various inversion techniques. These approaches have been applied in the past primarily to obtain source estimates for long-lived trace gases such as CO2. We consider the application of similar techniques to source estimation for atmospheric aerosols, by using as a case study the estimation of bacteria emissions from different ecosystem regions in the global atmospheric chemistry and climate model ECHAM5/MESSy-Atmospheric Chemistry (EMAC). Simulated particle concentrations in the tropopause region and at high latitudes, as well as transport of particles to tundra and land ice regions are shown to be highly sensitive to scavenging in mixed-phase clouds, which is poorly characterized in most global climate models. This may be a critical uncertainty in correctly simulating the transport of aerosol particles to the Arctic. Source estimation via Monte Carlo Markov Chain is applied to a suite of sensitivity simulations and the global mean emissions are estimated. We present an analysis of the partitioning of uncertainties in the global mean emissions that are attributable to particle size, CCN activity, the ice nucleation scavenging ratios for mixed-phase and cold clouds, and measurement error. Uncertainty due to CCN activity or to a 1 um error in particle size is typically between 10% and 40% of the uncertainty due to data uncertainty, as measured by the 5%-ile to 95%-ile range of the Monte Carlo ensemble. Uncertainty attributable to the ice nucleation scavenging ratio in mized-phase clouds is as high as 10% to 20% of the data uncertainty. Taken together, the four model 20 parameters examined contribute about half as much to the uncertainty in the estimated emissions as do the measurements. This was a surprisingly large contribution from model uncertainty in light of the substantial data uncertainty, which ranges from 81% to 870% for each of ten ecosystems for this case study. The effects of these and other model parameters in contributing to the uncertainties in the transport of atmospheric aerosol particles should be treated explicitly and systematically in both forward and inverse modelling studies.

Burrows, Susannah M.; Rayner, Perter; Butler, T.; Lawrence, M.

2013-06-04T23:59:59.000Z

376

Toward a Minimal Representation of Aerosols in Climate Models: Description and Evaluation in the Community Atmosphere Model CAM5  

Science Conference Proceedings (OSTI)

A modal aerosol module (MAM) has been developed for the Community Atmosphere Model version 5 (CAM5), the atmospheric component of the Community Earth System Model version 1 (CESM1). MAM is capable of simulating the aerosol size distribution and both internal and external mixing between aerosol components, treating numerous complicated aerosol processes and aerosol physical, chemical and optical properties in a physically based manner. Two MAM versions were developed: a more complete version with seven-lognormal modes (MAM7), and a three-lognormal mode version (MAM3) for the purpose of long-term (decades to centuries) simulations. Major approximations in MAM3 include assuming immediate mixing of primary organic matter (POM) and black carbon (BC) with other aerosol components, merging of the MAM7 fine dust and fine sea salt modes into the accumulation mode, merging of the MAM7 coarse dust and coarse sea salt modes into the single coarse mode, and neglecting the explicit treatment of ammonia and ammonium cycles. Simulated sulfate and secondary organic aerosol (SOA) mass concentrations are remarkably similar between MAM3 and MAM7 as most ({approx}90%) of these aerosol species are in the accumulation mode. Differences of POM and BC concentrations between MAM3 and MAM7 are also small (mostly within 10%) because of the assumed hygroscopic nature of POM, so that freshly emitted POM and BC are wet-removed before mixing internally with soluble aerosol species. Sensitivity tests with the POM assumed to be hydrophobic and with slower aging process increase the POM and BC concentrations, especially at high latitudes (by several times). The mineral dust global burden differs by 10% and sea salt burden by 30-40% between MAM3 and MAM7 mainly due to the different size ranges for dust and sea salt modes and different standard deviations of log-normal size distribution for sea salt modes between MAM3 and MAM7. The model is able to qualitatively capture the observed geographical and temporal variations of aerosol mass and number concentrations, size distributions, and aerosol optical properties. However, there are noticeable biases, e.g., simulated sulfate and mineral dust concentrations at surface over the oceans are too low. Simulated BC concentrations are significant low in the Arctic. There is a low bias in modeled aerosol optical depth on the global scale, especially in the developing counties. There biases in aerosol simulations clearly indicate the need for improvements of aerosol processes (e.g., emission fluxes of anthropogenic aerosols and precursor gases in developing countries, boundary layer nucleation) and properties (e.g., primary aerosol emission size, POM hygroscopicity). In addition the critical role of cloud properties (e.g., liquid water content, cloud fraction) responsible for the wet scavenging of aerosol is highlighted.

Liu, Xiaohong; Easter, Richard C.; Ghan, Steven J.; Zaveri, Rahul A.; Rasch, Philip J.; Shi, Xiangjun; Lamarque, J.-F.; Gettelman, A.; Morrison, H.; Vitt, Francis; Conley, Andrew; Park, S.; Neale, Richard; Hannay, Cecile; Ekman, A. M.; Hess, Peter; Mahowald, N.; Collins, William D.; Iacono, Michael J.; Bretherton, Christopher S.; Flanner, M. G.; Mitchell, David

2012-05-21T23:59:59.000Z

377

Earth and Atmospheric Sciences | More Science | ORNL  

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

Nuclear Forensics Climate & Environment Sensors and Measurements Chemical & Engineering Materials Computational Earth Science Systems Modeling Geographic Information Science and Technology Materials Science and Engineering Mathematics Physics More Science Home | Science & Discovery | More Science | Earth and Atmospheric Sciences SHARE Earth and Atmospheric Sciences At ORNL, we combine our capabilities in atmospheric science, computational science, and biological and environmental systems science to focus in the cross-disciplinary field of climate change science. We use computer models to improve climate change predications and to measure the impact of global warming on the cycling of chemicals in earth systems. Our Climate Change Science Institute uses models to explore connections among atmosphere,

378

Climate Modeling with Spectral Elements  

Science Conference Proceedings (OSTI)

As an effort toward improving climate model–component performance and accuracy, an atmospheric-component climate model has been developed, entitled the Spectral Element Atmospheric Climate Model and denoted as CAM_SEM. CAM_SEM includes a unique ...

Ferdinand Baer; Houjun Wang; Joseph J. Tribbia; Aimé Fournier

2006-12-01T23:59:59.000Z

379

A Parameterization for Land–Atmosphere-Cloud Exchange (PLACE): Documentation and Testing of a Detailed Process Model of the Partly Cloudy Boundary Layer over Heterogeneous Land  

Science Conference Proceedings (OSTI)

This paper presents a general description of, and demonstrates the capabilities of, the Parameterization for Land–Atmosphere–Cloud Exchange (PLACE). The PLACE model is a detailed process model of the partly cloudy atmospheric boundary layer and ...

Peter J. Wetzel; Aaron Boone

1995-07-01T23:59:59.000Z

380

Diagnostic computation of moisture budgets in the ERA-Interim Reanalysis with reference to analysis of CMIP-archived atmospheric model data  

Science Conference Proceedings (OSTI)

The diagnostic evaluation of moisture budgets in archived atmosphere model data is examined. Sources of error in diagnostic computation can arise from the use of numerical methods different to those used in the atmosphere model, the time and ...

Richard Seager; Naomi Henderson

Note: This page contains sample records for the topic "improving atmospheric models" 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

Diagnostic Computation of Moisture Budgets in the ERA-Interim Reanalysis with Reference to Analysis of CMIP-Archived Atmospheric Model Data  

Science Conference Proceedings (OSTI)

The diagnostic evaluation of moisture budgets in archived atmosphere model data is examined. Sources of error in diagnostic computation can arise from the use of numerical methods different from those used in the atmosphere model, the time and ...

Richard Seager; Naomi Henderson

2013-10-01T23:59:59.000Z

382

Sensitivity of the Aerosol Indirect Effect to Subgrid Variability in the Cloud Parameterization of the GFDL Atmosphere General Circulation Model AM3  

Science Conference Proceedings (OSTI)

The recently developed GFDL Atmospheric Model version 3 (AM3), an atmospheric general circulation model (GCM), incorporates a prognostic treatment of cloud drop number to simulate the aerosol indirect effect. Since cloud drop activation depends on ...

Jean-Christophe Golaz; Marc Salzmann; Leo J. Donner; Larry W. Horowitz; Yi Ming; Ming Zhao

2011-07-01T23:59:59.000Z

383

Evaluation of Near-Surface Parameters in the Two Versions of the Atmospheric Model in CESM1 using Flux Station Observations  

Science Conference Proceedings (OSTI)

This paper describes the performance of the Community Atmosphere Model (CAM) versions 4 and 5 in simulating near-surface parameters. CAM is the atmospheric component of the Community Earth System Model (CESM). Most of the parameterizations in the ...

Jenny Lindvall; Gunilla Svensson; Cecile Hannay

2013-01-01T23:59:59.000Z

384

Effects of diurnal variation on a tropical coupling system: a 2-dimensional coupled ocean-cloud resolving atmosphere modeling study  

Science Conference Proceedings (OSTI)

The effects of diurnal variation on tropical atmospheric and oceanic variability are investigated with a two-dimensional coupled ocean-cloud resolving atmosphere model. The experiment with a time-invariant solar zenith angle is compared to the control ... Keywords: diurnal variation, tropical coupling system

Shouting Gao; Yushu Zhou

2008-05-01T23:59:59.000Z

385

MPS Model-Based Software Acquisition Process Improvement in Brazil  

Science Conference Proceedings (OSTI)

This paper describes an initiative to improve software acquisition process in Brazil. This initiative was conducted in the context of the MPS.BR Program, a nationwide effort to develop and disseminate the MPS Model both in large organizations and Small ...

Kival Chaves Weber; Eratostenes Edson Ramalho de Araujo; Danilo Scalet; Edmeia Leonor Pereira de Andrade; Ana Regina Cavalcanti da Rocha; Mariano Angel Montoni

2007-09-01T23:59:59.000Z

386

Integrated model shows that atmospheric brown clouds and greenhouse gases have reduced rice harvests in India  

SciTech Connect

Previous studies have found that atmospheric brown clouds partially offset the warming effects of greenhouse gases. This finding suggests a tradeoff between the impacts of reducing emissions of aerosols and greenhouse gases. Results from a statistical model of historical rice harvests in India, coupled with regional climate scenarios from a parallel climate model, indicate that joint reductions in brown clouds and greenhouse gases would in fact have complementary, positive impacts on harvests. The results also imply that adverse climate change due to brown clouds and greenhouse gases contributed to the slowdown in harvest growth that occurred during the past two decades.

Auffhammer, M. [Univ. of California, Berkeley, CA (United States). Dept. of Agricultural and Resource Economics; Ramanathan, V. [Scripps Institution of Oceanography, San Diego, CA (United States); Vincent, J.R. [Univ. of California, San Diego, CA (United States). Graduate School of International Relations and Pacific Studies

2007-12-26T23:59:59.000Z

387

E – ? model of spray-laden near-sea atmospheric layer in high wind conditions  

Science Conference Proceedings (OSTI)

In-depth understanding and accurate modelling of the interaction between ocean spray and a turbulent flow under high-wind conditions is essential for improving intensity forecasts of hurricanes and severe storms. Here we consider the E – ? closure ...

Yevgenii Rastigejev; Sergey A. Suslov

388

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al. (2007)  

E-Print Network (OSTI)

Comment on "Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design" Teixeira et al.

Lun-Shin Yao; Dan Hughes

2007-04-26T23:59:59.000Z

389

A Numerical Model for Chemical and Meteorological Processes in the Atmospheric Boundary Layer. Part I: A Model Description and a One-Dimensional Parameter Study  

Science Conference Proceedings (OSTI)

A numerical flow model is presented for the atmospheric boundary layer, including dispersion and chemical transformations of air pollutants. The model is a three-dimensional time-dependent one for the mesoscale based on the conservation equations ...

Gunilla Svensson

1996-06-01T23:59:59.000Z

390

Investigation of the Summer Climate of the Contiguous United States and Mexico Using the Regional Atmospheric Modeling System (RAMS). Part I: Model Climatology (1950–2002)  

Science Conference Proceedings (OSTI)

Fifty-three years of the NCEP–NCAR Reanalysis I are dynamically downscaled using the Regional Atmospheric Modeling System (RAMS) to generate a regional climate model (RCM) climatology of the contiguous United States and Mexico. Data from the RAMS ...

Christopher L. Castro; Roger A. Pielke Sr.; Jimmy O. Adegoke

2007-08-01T23:59:59.000Z

391

New Approach to Calculation of Atmospheric Model Physics: Accurate and Fast Neural Network Emulation of Longwave Radiation in a Climate Model  

Science Conference Proceedings (OSTI)

A new approach based on a synergetic combination of statistical/machine learning and deterministic modeling within atmospheric models is presented. The approach uses neural networks as a statistical or machine learning technique for an accurate ...

Vladimir M. Krasnopolsky; Michael S. Fox-Rabinovitz; Dmitry V. Chalikov

2005-05-01T23:59:59.000Z

392

Statistics of the Air-Sea Fluxes of Momentum and Mechanical Energy in a Coupled Wave-Atmosphere Model  

Science Conference Proceedings (OSTI)

An atmospheric general circulation model (GCM) and a wind wave model are coupled through the wind stress. The wind stress which forces the wave model, depends in the coupled model on the stage of development of the wave field. As the waves depend ...

Susanne L. Weber

1994-06-01T23:59:59.000Z

393

An Investigation with a General Circulation Model of the Climatic Effects of Cloud Albedo Changes Caused by Atmospheric Pollution  

Science Conference Proceedings (OSTI)

A hemispheric general circulation model, with fixed zonally averaged cloud cover, was used to investigate the climatic impact of increased albedo of low-level clouds caused by atmospheric pollution. The albedo of these clouds was increased from ...

B. G. Hunt

1982-08-01T23:59:59.000Z

394

The Effect of Cold Climate upon North Atlantic Deep Water Formation in a Simple Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The sensitivity of North Atlantic Deep Water formation to variations in mean surface temperature is explored with a meridional-vertical plane ocean model coupled to an energy balance atmosphere. It is found that North Atlantic Deep Water ...

Michael Winton

1997-01-01T23:59:59.000Z

395

Modeling the Global Solar Radiation on the Earth’s Surface Using Atmospheric Deterministic and Intelligent Data-Driven Techniques  

Science Conference Proceedings (OSTI)

Three methods for analyzing and modeling the global shortwave radiation reaching the earth’s surface are presented in this study. Solar radiation is a very important input for many aspects of climatology, hydrology, atmospheric sciences, and ...

M. Santamouris; G. Mihalakakou; B. Psiloglou; G. Eftaxias; D. N. Asimakopoulos

1999-10-01T23:59:59.000Z

396

Gravity Wave Characteristics in the Southern Hemisphere Revealed by a High-Resolution Middle-Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

Gravity wave characteristics in the middle- to high-latitude Southern Hemisphere are analyzed using simulation data over 3 yr from a high-resolution middle-atmosphere general circulation model without using any gravity wave parameterizations. ...

Kaoru Sato; Satoshi Tateno; Shingo Watanabe; Yoshio Kawatani

2012-04-01T23:59:59.000Z

397

Implementing the Delta-Four-Stream Approximation for Solar Radiation Computations in an Atmosphere General Circulation Model  

Science Conference Proceedings (OSTI)

Proper quantification of the solar radiation budget and its transfer within the atmosphere is of utmost importance in climate modeling. The delta-four-stream (DFS) approximation has been demonstrated to offer a more accurate computational method ...

Tarek Ayash; Sunling Gong; Charles Q. Jia

2008-07-01T23:59:59.000Z

398

Interactive Crop Management in the Community Earth System Model (CESM1): Seasonal Influences on Land–Atmosphere Fluxes  

Science Conference Proceedings (OSTI)

The Community Earth System Model, version 1 (CESM1) is evaluated with two coupled atmosphere–land simulations. The CTRL (control) simulation represents crops as unmanaged grasses, while CROP represents a crop managed simulation that includes ...

Samuel Levis; Gordon B. Bonan; Erik Kluzek; Peter E. Thornton; Andrew Jones; William J. Sacks; Christopher J. Kucharik

2012-07-01T23:59:59.000Z

399

Atmospheric Turbulence above Coastal Waters: Determination of Stability Classes and a Simple Model for Offshore Flow Including Advection and Dissipation  

Science Conference Proceedings (OSTI)

Atmospheric turbulence intensities and timescales have been measured for one year and modeled in a shoreline environment. Measurements were carded out at two sites on both sides of the shoreline, about 10 km from the beach. The frequency ...

Hans J. Erbrink; Rudy D. A. Scholten

1995-10-01T23:59:59.000Z

400

Evaluation of Various Approximations in Atmosphere and Ocean Modeling based on an Exact Treatment of Gravity Wave Dispersion  

Science Conference Proceedings (OSTI)

Various approximations of the governing equations of compressible fluid dynamics are commonly used in both atmospheric and ocean modeling. Their main purpose is to eliminate the acoustic waves that are potentially responsible for inefficiency in ...

John K. Dukowicz

Note: This page contains sample records for the topic "improving atmospheric models" 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

A Nocturnal Atmospheric Drainage Flow Simulation Investigating the Application of One-Dimensional Modeling and Current Turbulence Schemes  

Science Conference Proceedings (OSTI)

We developed a one-dimensional boundary layer model to simulate nocturnal atmospheric drainage flow on a simple forest-covered slope using canopy, soil and radiation parameterizations from previous studies along with turbulence simulation (from ...

Warren Heilman; Ronald Dobosy

1985-09-01T23:59:59.000Z

402

A Cumulus Parameterization for Climate Studies of the Tropical Atmosphere. Part I: Model Formulation and Sensitivity Tests  

Science Conference Proceedings (OSTI)

A scheme for parameterizing the effects of cumulus convection for the maintenance of the thermodynamic structure of the tropical atmosphere is described. This parameterization is used in a one-dimensional model that represents the vertical ...

Bruce A. Albrecht

1983-09-01T23:59:59.000Z

403

Convergence Rate and Stability of Ocean-Atmosphere Coupling Schemes with a Zero-Dimensional Climate Model  

Science Conference Proceedings (OSTI)

A zero-dimensional climate model is considered with three thermal reservoirs, i.e., the atmosphere, the surface mixed layer and the intermediate water of the ocean. Realistic values are adopted for the rates of heat transfer between those ...

Robert E. Dickinson

1981-10-01T23:59:59.000Z

404

Comparisons of empirical localization techniques for serial ensemble Kalman filters in a simple atmospheric general circulation model  

Science Conference Proceedings (OSTI)

Two techniques for estimating good localization functions for serial ensemble Kalman filters are compared in observing system simulation experiments (OSSE) conducted with the dynamical core of an atmospheric general circulation model. The first ...

Lili Lei; Jeffrey L. Anderson

405

Modeling the Atmospheric Convective Boundary Layer within a Zero-Order Jump Approach: An Extended Theoretical Framework  

Science Conference Proceedings (OSTI)

The paper presents an extended theoretical background for applied modeling of the atmospheric convective boundary layer within the so-called zero-order jump approach, which implies vertical homogeneity of meteorological fields in the bulk of ...

Evgeni Fedorovich

1995-09-01T23:59:59.000Z

406

Status of and Outlook for Large-Scale Modeling of Atmosphere–Ice–Ocean Interactions in the Arctic  

Science Conference Proceedings (OSTI)

Arctic air masses have direct impacts on the weather and climatic extremes of midlatitude areas such as central North America. Arctic physical processes pose special and very important problems for global atmospheric models used for climate ...

David Randall; Judith Curry; David Battisti; Gregory Flato; Robert Grumbine; Sirpa Hakkinen; Doug Martinson; Ruth Preller; John Walsh; John Weatherly

1998-02-01T23:59:59.000Z

407

Convective Entrainment into a Shear-Free, Linearly Stratified Atmosphere: Bulk Models Reevaluated through Large Eddy Simulations  

Science Conference Proceedings (OSTI)

Relationships between parameters of convective entrainment into a shear-free, linearly stratified atmosphere predicted by the zero-order jump and general-structure bulk models of entrainment are reexamined using data from large eddy simulations (...

Evgeni Fedorovich; Robert Conzemius; Dmitrii Mironov

2004-02-01T23:59:59.000Z

408

A Simple Coupled Atmosphere–Ocean–Sea Ice–Land Surface Model for Climate and Paleoclimate Studies  

Science Conference Proceedings (OSTI)

The authors develop a coupled atmosphere–ocean–sea ice–land surface model for long-term climate change studies that incorporates the seasonal cycle. Three ocean basins, the Antarctic Circumpolar Current region, and the major continents are ...

Zhaomin Wang; Lawrence A. Mysak

2000-03-01T23:59:59.000Z

409

Influence of Land Surface Roughness on Atmospheric Circulation and Precipitation: A Sensitivity Study with a General Circulation Model  

Science Conference Proceedings (OSTI)

The influence of land surface roughness on the large scale atmospheric circulation and rainfall was examined by comparing three sets of simulations made with a general circulation model in which the land surface roughness length, z0, was reduced ...

Y. C. Sud; J. Shukla; Y. Mintz

1988-09-01T23:59:59.000Z

410

Baroclinic Adjustment in an Atmosphere–Ocean Thermally Coupled Model: The Role of the Boundary Layer Processes  

Science Conference Proceedings (OSTI)

Baroclinic eddy equilibration and the roles of different boundary layer processes in limiting the baroclinic adjustment are studied using an atmosphere–ocean thermally coupled model. Boundary layer processes not only affect the dynamical ...

Yang Zhang; Peter H. Stone

2011-11-01T23:59:59.000Z

411

Conservative Semi-Lagrangian Transport on a Sphere and the Impact on Vapor Advection in an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

A conservative semi-Lagrangian scheme with rational function for interpolation is implemented in spherical geometry and tested in an atmospheric general circulation model (AGCM). The new scheme, different from the conventional semi-Lagrangian ...

Xindong Peng; Feng Xiao; Wataru Ohfuchi; Hiromitsu Fuchigami

2005-03-01T23:59:59.000Z

412

Simulation of the Global Hydrological Cycle in the CCSM Community Atmosphere Model Version 3 (CAM3): Mean Features  

Science Conference Proceedings (OSTI)

The seasonal and annual climatological behavior of selected components of the hydrological cycle are presented from coupled and uncoupled configurations of the atmospheric component of the Community Climate System Model (CCSM) Community ...

James J. Hack; Julie M. Caron; Stephen G. Yeager; Keith W. Oleson; Marika M. Holland; John E. Truesdale; Philip J. Rasch

2006-06-01T23:59:59.000Z

413

Semidiurnal Variations in the Budget of Angular Momentum in a General Circulation Model and in the Real Atmosphere  

Science Conference Proceedings (OSTI)

Diurnal and semidiurnal variations in the budget of atmospheric angular momentum are evident in a simulation by the NCAR Community Climate Model (CCM2). These variations depicted with 20-min time resolution (each time step) are used as guides to ...

Roland A. Madden; Harald Lejenäs; James Hack

1998-08-01T23:59:59.000Z

414

Equilibrium Response of an Atmosphere–Mixed Layer Ocean Model to Different Radiative Forcing Agents: Global and Zonal Mean Response  

Science Conference Proceedings (OSTI)

The equilibrium response to various forcing agents, including CO2, solar irradiance, tropospheric ozone, black carbon, organic carbon, sulfate, and volcanic aerosols, is investigated using an atmospheric general circulation model coupled to a ...

Masakazu Yoshimori; Anthony J. Broccoli

2008-09-01T23:59:59.000Z

415

Very narrow band model calculations of atmospheric fluxes and cooling rates  

SciTech Connect

A new very narrow band model (VNBM) approach has been developed and incorporated into the MODTRAN atmospheric transmittance-radiance code. The VNBM includes a computational spectral resolution of 1 cm{sup {minus}1}, a single-line Voigt equivalent width formalism that is based on the Rodgers-Williams approximation and accounts for the finite spectral width of the interval, explicit consideration of line tails, a statistical line overlap correction, a new sublayer integration approach that treats the effect of the sublayer temperature gradient on the path radiance, and the Curtis-Godson (CG) approximation for inhomogeneous paths. A modified procedure for determining the line density parameter 1/d is introduced, which reduces its magnitude. This results in a partial correction of the VNBM tendency to overestimate the interval equivalent widths. The standard two parameter CG approximation is used for H{sub 2}O and CO{sub 2}, while the Goody three parameter CG approximation is used for O{sub 3}. Atmospheric flux and cooling rate predictions using a research version of MODTRAN, MODR, are presented for H{sub 2}O (with and without the continuum), CO{sub 2}, and O{sub 3} for several model atmospheres. The effect of doubling the CO{sub 2} concentration is also considered. These calculations are compared to line-by-line (LBL) model calculations using the AER, GLA, GFDL, and GISS codes. The MODR predictions fall within the spread of the LBL results. The effects of decreasing the band model spectral resolution are illustrated using CO{sub 2} cooling rate and flux calculations. 36 refs., 18 figs., 1 tab.

Bernstein, L.S.; Berk, A.; Acharya, P.K.; Robertson, D.C. [Spectral Sciences, Inc., Burlington, MA (United States)] [and others] [Spectral Sciences, Inc., Burlington, MA (United States); and others

1996-10-15T23:59:59.000Z

416

Security Analysis and Improvement Model for Web-based Applications  

E-Print Network (OSTI)

Today the web has become a major conduit for information. As the World Wide Web?s popularity continues to increase, information security on the web has become an increasing concern. Web information security is related to availability, confidentiality, and data integrity. According to the reports from http://www.securityfocus.com in May 2006, operating systems account for 9% vulnerability, web-based software systems account for 61% vulnerability, and other applications account for 30% vulnerability. In this dissertation, I present a security analysis model using the Markov Process Model. Risk analysis is conducted using fuzzy logic method and information entropy theory. In a web-based application system, security risk is most related to the current states in software systems and hardware systems, and independent of web application system states in the past. Therefore, the web-based applications can be approximately modeled by the Markov Process Model. The web-based applications can be conceptually expressed in the discrete states of (web_client_good; web_server_good, web_server_vulnerable, web_server_attacked, web_server_security_failed; database_server_good, database_server_vulnerable, database_server_attacked, database_server_security_failed) as state space in the Markov Chain. The vulnerable behavior and system response in the web-based applications are analyzed in this dissertation. The analyses focus on functional availability-related aspects: the probability of reaching a particular security failed state and the mean time to the security failure of a system. Vulnerability risk index is classified in three levels as an indicator of the level of security (low level, high level, and failed level). An illustrative application example is provided. As the second objective of this dissertation, I propose a security improvement model for the web-based applications using the GeoIP services in the formal methods. In the security improvement model, web access is authenticated in role-based access control using user logins, remote IP addresses, and physical locations as subject credentials to combine with the requested objects and privilege modes. Access control algorithms are developed for subjects, objects, and access privileges. A secure implementation architecture is presented. In summary, the dissertation has developed security analysis and improvement model for the web-based application. Future work will address Markov Process Model validation when security data collection becomes easy. Security improvement model will be evaluated in performance aspect.

Wang, Yong

2008-12-01T23:59:59.000Z

417

New extended atomic data in cool star model atmospheres - Using Kurucz's new iron data in MAFAGS-OS models  

E-Print Network (OSTI)

Context. Cool star model atmospheres are a common tool for the investigation of stellar masses, ages and elemental abundance composition. Theoretical atmospheric models strongly depend on the atomic data used when calculating them. Aims. We present the changes in flux and temperature stratification when changing from iron data computed by R.L. Kurucz in the mid 90s to the Kurucz 2009 iron computations. Methods. MAFAGS-OS opacity sampling atmospheres were recomputed with Kurucz 2009 iron atomic data as implemented in the VALD database by Ryabchikova. Temperature stratification and emergent flux distribution of the new version, called MAFAGS-OS9, is compared to the former version and to solar flux measurements. Results. Using the Kurucz line lists converted into the VALD format and new bound-free opacities for Mg i and Al i leads to changes in the solar temperature stratification by not more than 28 K. At the same time, the calculated solar flux distribution shows significantly better agreement between observat...

Grupp, F; Tan, K

2009-01-01T23:59:59.000Z

418

Cloud-radiative effects on implied oceanic energy transports as simulated by atmospheric general circulation models  

DOE Green Energy (OSTI)

This paper reports on energy fluxes across the surface of the ocean as simulated by fifteen atmospheric general circulation models in which ocean surface temperatures and sea-ice boundaries are prescribed. The oceanic meridional energy transport that would be required to balance these surface fluxes is computed, and is shown to be critically sensitive to the radiative effects of clouds, to the extent that even the sign of the Southern Hemisphere ocean energy transport can be affected by the errors in simulated cloud-radiation interactions.

Gleckler, P.J. [Lawrence Livermore National Lab., CA (United States); Randall, D.A. [Colorado State Univ., Fort Collins, CO (United States); Boer, G. [Canadian Climate Centre, Victoria (Canada)

1994-03-01T23:59:59.000Z

419

Atmospheric transmittance model for a solar beam propagating between a heliostat and a receiver  

Science Conference Proceedings (OSTI)

This report presents formulae that provide reliable estimates of the percent energy loss P/sub L/ (or, equivalently, the transmittance tau) of a solar beam propagating between a heliostat and a receiver. These formulae are wavelength-independent, functional fits to the tabulated results of Vittitoe and Biggs, which in turn are the results of numerical integrations of spectral transmittance data calculated with the aid of the computer code LOWTRAN 3. The formulae allow for interpolation and extrapolation and have a form characteristic of atmospheric transmittance models.

Pitman, C.L.; Vant-Hull, L.L.

1984-02-01T23:59:59.000Z

420

Characteristics of Drought and Persistent Wet Spells over the United States in the Atmosphere–Land–Ocean Coupled Model Experiments  

Science Conference Proceedings (OSTI)

Atmosphere–land–ocean coupled model simulations are examined to diagnose the ability of models to simulate drought and persistent wet spells over the United States. A total of seven models are selected for this study. They are three versions of ...

Kingtse C. Mo; Lindsey N. Long; Jae-Kyung E. Schemm

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

An improved dosimetric model of the head and brain  

E-Print Network (OSTI)

During the last decade, various brain imaging methods using radionuclides have become available. Due to the introduction of new techniques, a small-scale dosimetry study of the brain, and more specifically the organs of the head (brain, eyes thyroid, skull, skin) was needed. However, the brain and head models developed in the past were crude representations of the human. In this research, a new brain model has been developed which includes eight subregions. This head model was included in a revised head model developed by Posion et al. in 1984. Some corrections and improvements were added to this head model such as the development of a new spinal region and a new cranium region in order to incorporate the cerebrospinal fluid. This model was used with a Monte Carlo code, EGS4, to calculate absorbed fraction of energy and specific absorbed fraction of energy for photon and electron sources located in one of thirteen chosen source regions. These calculations were made for radiations in the energy range 10 keV to 4 MeV. All twenty-three regions included in the revised head and brain model were taken as target regions. S-values were also calculated for several radionuclides used in brain imaging, and also deposited in the thyroid, the skull or the spinal skeleton. The S-values were calculated using discrete energy points on the beta emission spectrum of the radionuclides.

Bouchet, Lionel Gerard

1995-01-01T23:59:59.000Z

422

How Much Do Different Land Models Matter for Climate Simulation? Part II: A Decomposed View of the Land–Atmosphere Coupling Strength  

Science Conference Proceedings (OSTI)

The Global Land–Atmosphere Coupling Experiment (GLACE) built a framework to estimate the strength of the land–atmosphere interaction across many weather and climate models. Within this framework, GLACE-type experiments are performed with a single ...

Jiangfeng Wei; Paul A. Dirmeyer; Zhichang Guo

2010-06-01T23:59:59.000Z

423

Origin of the Springtime Westerly Bias in Equatorial Atlantic Surface Winds in the Community Atmosphere Model Version 3 (CAM3) Simulation  

Science Conference Proceedings (OSTI)

This study makes the case that westerly bias in the surface winds of the National Center for Atmospheric Research (NCAR) Community Atmosphere Model, version 3 (CAM3), over the equatorial Atlantic in boreal spring has its origin in the rainfall (...

Ching-Yee Chang; Sumant Nigam; James A. Carton

2008-09-01T23:59:59.000Z

424

Extreme Value Statistics of the Total Energy in an Intermediate-Complexity Model of the Midlatitude Atmospheric Jet. Part I: Stationary Case  

Science Conference Proceedings (OSTI)

A baroclinic model of intermediate complexity for the atmospheric jet at middle latitudes is used as a stochastic generator of atmosphere-like time series. In this case, time series of the total energy of the system are considered. Statistical ...

Mara Felici; Valerio Lucarini; Antonio Speranza; Renato Vitolo

2007-07-01T23:59:59.000Z

425

Evaluation of Model-Predicted Top-of-Atmosphere Radiation and Cloud Parameters over Africa with Observations from GERB and SEVIRI  

Science Conference Proceedings (OSTI)

This study compared the Regional Atmospheric Climate Model version 2 (RACMO) with satellite data by simultaneously looking at cloud properties and top-of-atmosphere (TOA) fluxes. This study used cloud properties retrieved from Spinning Enhanced ...

Wouter Greuell; Erik van Meijgaard; Nicolas Clerbaux; Jan Fokke Meirink

2011-08-01T23:59:59.000Z

426

Thermohaline Circulation Stability: A Box Model Study. Part II: Coupled Atmosphere–Ocean Model  

Science Conference Proceedings (OSTI)

A thorough analysis of the stability of a coupled version of an interhemispheric three-box model of thermohaline circulation (THC) is presented. This study follows a similarly structured analysis of an uncoupled version of the same model ...

Valerio Lucarini; Peter H. Stone

2005-02-01T23:59:59.000Z

427

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

SciTech Connect

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

Howard Barker; Jason Cole

2012-05-17T23:59:59.000Z

428

Improving the Contribution of Economic Models in Evaluating Industrial Energy Efficiency Improvements  

E-Print Network (OSTI)

Traditional representation of improved end-use efficiency in the manufacturing sector has tended to assume “a net cost” perspective. In other words, the assumption for many models is that any change within the energy end-use patterns must imply a cost without concomitant energy bill savings. This tends to significantly overstate the cost of new energy policies. Yes, the range of technologies available to satisfy end-use service demands does require (admittedly) a significant level of capital. But more often than not, there is a return on that investment; and that return on investment is typically overlooked in many of the standard economic policy models. This paper describes the differences between many of the conventional energy models now used for energy policy assessments compared to those which more properly reflect a trade-off between new capital investment and end-use energy savings – as both capital and energy are used to satisfy a specific industrial service demand. The paper builds on a discussion provided by Neal Elliott for approximating service demands within food products manufacturing (NAICS 311). It then shows how the proper treatment of investment flows may provide a different outcome for policy assessments than might be provided by the standard policy models.

Laitner, J. A.

2007-01-01T23:59:59.000Z

429

Two Improved Mixture Weibull Models for the Analysis of Wind Speed Data  

Science Conference Proceedings (OSTI)

In this paper, the authors propose two improved mixture Weibull distribution models by adding one or two location parameters to the existing two-component mixture two-parameter Weibull distribution [MWbl(2, 2)] model. One improved model is the ...

Xu Qin; Jiang-she Zhang; Xiao-dong Yan

2012-07-01T23:59:59.000Z

430

A New Ensemble of Perturbed-Input-Parameter Simulations by the Community Atmosphere Model  

SciTech Connect

Uncertainty quantification (UQ) is a fundamental challenge in the numerical simulation of Earth's weather and climate, and other complex systems. It entails much more than attaching defensible error bars to predictions: in particular it includes assessing low-probability but high-consequence events. To achieve these goals with models containing a large number of uncertain input parameters, structural uncertainties, etc., raw computational power is needed. An automated, self-adapting search of the possible model configurations is also useful. Our UQ initiative at the Lawrence Livermore National Laboratory has produced the most extensive set to date of simulations from the US Community Atmosphere Model. We are examining output from about 3,000 twelve-year climate simulations generated with a specialized UQ software framework, and assessing the model's accuracy as a function of 21 to 28 uncertain input parameter values. Most of the input parameters we vary are related to the boundary layer, clouds, and other sub-grid scale processes. Our simulations prescribe surface boundary conditions (sea surface temperatures and sea ice amounts) to match recent observations. Fully searching this 21+ dimensional space is impossible, but sensitivity and ranking algorithms can identify input parameters having relatively little effect on a variety of output fields, either individually or in nonlinear combination. Bayesian statistical constraints, employing a variety of climate observations as metrics, also seem promising. Observational constraints will be important in the next step of our project, which will compute sea surface temperatures and sea ice interactively, and will study climate change due to increasing atmospheric carbon dioxide.

Covey, C; Brandon, S; Bremer, P T; Domyancis, D; Garaizar, X; Johannesson, G; Klein, R; Klein, S A; Lucas, D D; Tannahill, J; Zhang, Y

2011-10-27T23:59:59.000Z

431

Adjusting to policy expectations in climate change modeling : an interdiciplinary study of flux adjustments in coupled atmosphere-ocean general circulation models  

E-Print Network (OSTI)

This paper surveys and interprets the attitudes of scientists to the use of flux adjustments in climate projections with coupled Atmosphere Ocean General Circulation Models. The survey is based largely on the responses of ...

Shackley, Simon.; Risbey, James; Stone, Peter H.; Wynne, Brian

432

Computational Efficiency and Accuracy of Methods for Asynchronously Coupling Atmosphere–Ocean Climate Models. Part I: Testing with a Mean Annual Model  

Science Conference Proceedings (OSTI)

Using the mean annual, globally-averaged, coupled atmosphere–ocean energy balance model of Harvey and Schneider, the effect on the transient climate response to a step function solar constant increase using a variety of asynchronous coupling ...

S. H. Schneider; L. D. D. Harvey

1986-01-01T23:59:59.000Z

433

Predictive Fallout Composition Modeling: Improvements and Applications of the Defense Land Fallout Interpretive Code  

SciTech Connect

This paper outlines several improvements to the Particle Activity Module of the Defense Land Fallout Interpretive Code (DELFIC). The modeling of each phase of the fallout process is discussed within DELFIC to demonstrate the capabilities and limitations with the code for modeling and simulation. Expansion of the DELFIC isotopic library to include actinides and light elements is shown. Several key features of the new library are demonstrated, including compliance with ENDF/B-VII standards, augmentation of hardwired activated soil and actinide decay calculations with exact Bateman calculations, and full physical and chemical fractionation of all material inventories. Improvements to the radionuclide source term are demonstrated, including the ability to specify heterogeneous fission types and the ability to import source terms from irradiation calculations using the Oak Ridge Isotope Generation (ORIGEN) code. Additionally, the dose, kerma, and effective dose conversion factors are revised. Finally, the application of DELFIC for consequence management planning and forensic analysis is presented. For consequence management, DELFIC is shown to provide disaster recovery teams with simulations of real-time events, including the location, composition, time of arrival, activity rates, and dose rates of fallout, accounting for site-specific atmospheric effects. The results from DELFIC are also demonstrated for use by nuclear forensics teams to plan collection routes (including the determination of optimal collection locations), estimate dose rates to collectors, and anticipate the composition of material at collection sites. These capabilities give mission planners the ability to maximize their effectiveness in the field while minimizing risk to their collectors.

Hooper, David A [ORNL; Jodoin, Vincent J [ORNL; Lee, Ronald W [ORNL; Monterial, Mateusz [ORNL

2012-01-01T23:59:59.000Z

434

Data Assimilation of Satellite-Derived Heating Rates as Proxy Surface Wetness Data into a Regional Atmospheric Mesoscale Model. Part I: Methodology  

Science Conference Proceedings (OSTI)

A satellite data assimilation method is developed which incorporates satellite-observed infrared heating rates into a mesoscale atmospheric model to retrieve model soil moisture. The method builds upon previous work with the model’s surface ...

Andrew S. Jones; Ingrid C. Guch; Thomas H. Vonder Haar

1998-03-01T23:59:59.000Z

435

Improvement of Orographic Gravity Wave Parameterization Using a Mesoscale Gravity Wave Model  

Science Conference Proceedings (OSTI)

Parameterization of gravity waves due to subgrid-scale orography is now included in most existing large-scale models of the atmosphere. Parameterization schemes, however, have so far been evaluated mainly in view of the overall performance of the ...

Young-Joon Kim; Akio Arakawa

1995-06-01T23:59:59.000Z

436

An Improved Land Surface Emissivity Parameter for Land Surface Models Using Global Remote Sensing Observations  

Science Conference Proceedings (OSTI)

Because land surface emissivity (?) has not been reliably measured, global climate model (GCM) land surface schemes conventionally set this parameter as simply constant, for example, 1 as in the National Oceanic and Atmospheric Administration (...

Menglin Jin; Shunlin Liang

2006-06-01T23:59:59.000Z

437

About the Reliability of Manual Model PV Corrections to Improve Forecasts  

Science Conference Proceedings (OSTI)

The National Weather Forecast Centre of Météo-France has developed a tool that corrects the state of the atmosphere within the Action de Recherche Petite Echelle Grande Echelle (ARPEGE) operational global model by adjusting the potential vorticity ...

Philippe Arbogast; Karine Maynard; Catherine Piriou

2012-12-01T23:59:59.000Z

438

A Bottom-Up Model to Estimate the Energy Efficiency Improvement...  

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

Efficiency Improvement and CO2 Emission Reduction Potentials in the Chinese Iron and Steel Industry Title A Bottom-Up Model to Estimate the Energy Efficiency Improvement and...

439

Predictability of Seasonal Sahel Rainfall Using GCMs and Lead-Time Improvements Through the Use of a Coupled Model  

Science Conference Proceedings (OSTI)

The ability of several atmosphere-only and coupled ocean–atmosphere general circulation models (AGCMs and CGCMs, respectively) is explored for the prediction of seasonal July–September (JAS) Sahel rainfall. The AGCMs driven with observed sea ...

Ousmane Ndiaye; M. Neil Ward; Wassila M. Thiaw

2011-04-01T23:59:59.000Z

440

Do Global Models Properly Represent the Feedback between Land and Atmosphere?  

Science Conference Proceedings (OSTI)

The Global Energy and Water Cycle Experiment/Climate Variability and Predictability (GEWEX/CLIVAR) Global Land–Atmosphere Coupling Experiment (GLACE) has provided an estimate of the global distribution of land–atmosphere coupling strength during ...

Paul A. Dirmeyer; Randal D. Koster; Zhichang Guo

2006-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

Atmospheric Release Advisory Capability: Real-Time Modeling of Airborne Hazardous Materials  

Science Conference Proceedings (OSTI)

The Atmospheric Release Advisory Capability (ARAC) at Lawrence Livermore National Laboratory is a centralized federal project for assessing atmospheric releases of hazardous materials in real time. Since ARAC began making assessments in 1974, the ...

Thomas J. Sullivan; James S. Ellis; Connee S. Foster; Kevin T. Foster; Ronald L. Baskett; John S. Nasstrom; Walter W. Schalk III

1993-12-01T23:59:59.000Z

442

Interpreting the Atmospheric Circulation Trend during the Last Half of the Twentieth Century: Application of an Adjoint Model  

Science Conference Proceedings (OSTI)

A tangent linear adjoint for a low-resolution dynamical model of the atmosphere is used to derive the optimal forcing perturbations for all state variables such that after a specified lead time the model response has a given projection, in terms ...

Simon Blessing; Richard J. Greatbatch; Klaus Fraedrich; Frank Lunkeit

2008-09-01T23:59:59.000Z

443

Interpreting the atmospheric circulation trend during the last half of the 20th century: Application of an adjoint model  

Science Conference Proceedings (OSTI)

A tangent linear adjoint for a low resolution dynamical model of the atmosphere is used to derive the optimal forcing perturbations for all state variables such that after a specified lead time the model response has a given projection, in terms ...

Simon Blessing; Klaus Fraedrich; Frank Lunkeit; Richard J. Greatbatch

444

Seasonal Climatic Changes Induced by Doubled CO2 as Simulated by the OSU Atmospheric GCM/Mixed-Layer Ocean Model  

Science Conference Proceedings (OSTI)

The OSU global atmospheric general circulation model (AGCM) has been coupled to a 60-m deep mixed-layer ocean model to simulate the equilibrium seasonal climatic changes induced by a doubling of the CO2 concentration. Simulations with CO2 ...

Michael E. Schlesinger; Zong-ci Zhao

1989-05-01T23:59:59.000Z

445

A Coupled Biosphere–Atmosphere Climate Model Suitable for Studies of Climatic Change Due to Land Surface Alterations  

Science Conference Proceedings (OSTI)

A biosphere model based on BATS (Biosphere–Atmosphere Transfer Scheme) is coupled to a primitive equation global statistical–dynamical model in order to study the climatic impact due to land surface alterations. The fraction of the earth’s ...

Mário Adelmo Varejão-Silva; Sergio H. Franchito; Vadlamudi Brahmananda Rao

1998-07-01T23:59:59.000Z

446

Evaluation of the Vertical Structure of Zonally Averaged Cloudiness and Its Variability in the Atmospheric Model Intercomparison Project  

Science Conference Proceedings (OSTI)

Estimates of zonally averaged cloudiness at each pressure level in 24 models participating in the Atmospheric Model Intercomparison Project are compared with the ISCCP C2 as well as the Nimbus 7 (N7) and Warren et al. (hereafter WH) observations. ...

Bryan C. Weare; Amip Modeling Groups

1996-12-01T23:59:59.000Z

447

The k?3 and k?5/3 Energy Spectrum of Atmospheric Turbulence: Quasigeostrophic Two-Level Model Simulation  

Science Conference Proceedings (OSTI)

The Nastrom–Gage energy spectrum of atmospheric turbulence as a function of wavelength is simulated here with a two-level quasigeostrophic (QG) model. This simple model has no topography, no direct wave forcing, and no small-scale forcing, nor ...

Ka Kit Tung; Wendell Welch Orlando

2003-03-01T23:59:59.000Z

448

TWP-ICE Global Atmospheric Model Intercomparison: Convection Responsiveness and Resolution Impact  

SciTech Connect

Results are presented from an intercomparison of global atmospheric model (GAM) simulations of tropical convection during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE). The distinct cloud properties, precipitation, radiation, and vertical diabatic heating profiles associated with three different monsoon regimes (wet, dry, and break) from available observations are used to evaluate 9 GAM forecasts initialized daily from realistic global analyses. All models well captured the evolution of large-scale circulation and the thermodynamic fields, but cloud properties differed substantially among models. For example, liquid water path and ice water path differed by up to two orders of magnitude. Compared with the relatively well simulated top-heavy heating structures during the wet and break period, most models had difficulty in depicting the bottom-heavy heating profiles associated with cumulus congestus. The best performing models during this period were the ones whose convection scheme was most responsive to the free tropospheric humidity. Compared with the large impact of cloud and convective parameterizations on model cloud and precipitation characteristics, resolution has relatively minor impact on simulated cloud properties. However, one feature that was influence by the resolution study in several models was the diurnal cycle of precipitation. Peaking at a different time from convective precipitation, large-scale precipitation generally increases in high resolution forecasts and modulates the total precipitation diurnal cycle. Overall, the study emphasizes the importance of more environmental responsive convective parameterizations to capture various types of convection and the substantial diversity among large-scale cloud and precipitation schemes in current GAMs. This experiment has also demonstrated itself to be a very useful testbed for those developing cloud and convection schemes in these models.

Lin, Yanluan; Donner, Leo J.; Petch, Jon C.; Bechtold, P.; Boyle, James; Klein, Stephen A.; Komori, T.; Wapler, K.; Willett, M.; Xie, X.; Zhao, M.; Xie, Shaocheng; McFarlane, Sally A.; Schumacher, Courtney

2012-05-08T23:59:59.000Z

449

Present-Day and Last-Glacial-Maximum Ocean Thermohaline Circulation in a Zonally Averaged Coupled Ocean–Sea-Ice–Atmosphere Model  

Science Conference Proceedings (OSTI)

A simple ocean–atmosphere model suitable for long-term paleoclimate studies is presented. It consists of a three-basin zonally averaged ocean model coupled to an energy moisture-balance atmospheric model and a thermodynamic sea-ice model. The ...

H. Bjornsson; L. A. Mysak

2001-04-01T23:59:59.000Z

450

Ecosystem Feedbacks to Climate Change in California: Development, Testing, and Analysis Using a Coupled Regional Atmosphere and Land Surface Model (WRF3–CLM3.5)  

Science Conference Proceedings (OSTI)

A regional atmosphere model [Weather Research and Forecasting model version 3 (WRF3)] and a land surface model [Community Land Model, version 3.5 (CLM3.5)] were coupled to study the interactions between the atmosphere and possible future ...

Z. M. Subin; W. J. Riley; J. Jin; D. S. Christianson; M. S. Torn; L. M. Kueppers

2011-05-01T23:59:59.000Z

451

The Atmospheric Radiation Measurement (ARM) Program: Programmatic Background and Design of the Cloud and Radiation Test Bed  

Science Conference Proceedings (OSTI)

The Atmospheric Radiation Measurement (ARM) Program, supported by the U.S. Department of Energy, is a major new program of atmospheric measurement and modeling. The program is intended to improve the understanding of processes that affect ...

Gerald M. Stokes; Stephen E. Schwartz

1994-07-01T23:59:59.000Z

452

Comparing modeled isoprene with aircraft-based measurements in the atmospheric boundary layer.  

Science Conference Proceedings (OSTI)

Nonmethane hydrocarbons (NMHCs) are involved in a complex series of reactions that regulate the levels of oxidants in the troposphere. Isoprene (C{sub 5}H{sub 8}), the primary NMHC emitted from deciduous trees, is one of the most important reactive hydrocarbons in the troposphere. The amount of isoprene entering the free troposphere is regulated by the compound's rate of emission from leaves and by chemical and physical processes in the forest canopy and the atmospheric boundary layer (ABL). This study uses a coupled canopy-ABL model to simulate these complex processes and compares calculated isoprene concentration profiles with those measured during aircraft flights above a forested region in the northeastern US. Land use information is coupled with satellite remote sensing data to describe spatial changes in canopy density during the field measurements. The high-resolution transport-chemistry model of Gao et al. (1993) for the ABL and the forest canopy layer is used to simulate vertical changes in isoprene concentration due to turbulent mixing and chemical reactions. The one-dimensional (1-D) ABL model includes detailed radiation transfer, turbulent diffusion, biogenic emissions, dry deposition, and chemical processes within the forest canopy and the ABL. The measured profiles are compared with the model simulations to investigate the biological, physical, and chemical processes that regulate the levels of isoprene within the ABL.

Doskey, P.; Gao, W.

1997-12-12T23:59:59.000Z

453

Development of the first nonhydrostatic nested-grid grid-point global atmospheric modeling system on parallel machines  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Evaluating the importance of global and regional climate response to increasing atmospheric concentrations of greenhouse gases requires a comprehensive global atmospheric modeling system (GAMS) capable of simulations over a wide range of atmospheric circulations, from complex terrain to continental scales, on high-performance computers. Unfortunately, all of the existing global circulation models (GCMs) do not meet this requirements, because they suffer from one or more of the following three shortcomings: (1) use of the hydrostatic approximation, which makes the models potentially ill-posed; (2) lack of a nested-grid (or multi-grid) capability, which makes it difficult to consistently evaluate the regional climate response to the global warming, and (3) spherical spectral (opposed to grid-point finite-difference) representation of model variables, which hinders model performance for parallel machine applications. The end product of the research is a highly modularized, multi-gridded, self-calibratable (for further parameterization development) global modeling system with state-of-the-science physics and chemistry. This system will be suitable for a suite of atmospheric problems: from local circulations to climate, from thunderstorms to global cloud radiative forcing, from urban pollution to global greenhouse trace gases, and from the guiding of field experiments to coupling with ocean models. It will also provide a unique testbed for high-performance computing architecture.

Kao, C.Y.J.; Langley, D.L.; Reisner, J.M.; Smith, W.S.

1998-11-01T23:59:59.000Z

454

Studies of regional-scale climate variability and change: Hidden Markov models and coupled ocean-atmosphere modes  

SciTech Connect

In this project we developed further a twin approach to the study of regional-scale climate variability and change. The two approaches involved probabilistic network (PN) models (sometimes called dynamic Bayesian networks) and intermediate-complexity coupled ocean-atmosphere models (ICMs). We thus made progress in identifying the predictable modes of climate variability and investigating their impacts on the regional scale. In previous work sponsored by DOE�s Climate Change Prediction Program (CCPP), we had developed a family of PNs (similar to Hidden Markov Models) to simulate historical records of daily rainfall, and used them to downscale seasonal predictions of general circulation models (GCMs). Using an idealized atmospheric model, we had established a novel mechanism through which ocean-induced sea-surface temperature (SST) anomalies might in�uence large-scale atmospheric circulation patterns on interannual and longer time scales; similar patterns were found in a hybrid coupled ocean�atmosphere�sea-ice model. In this continuation project, we built on these ICM results and PN model development to address prediction of rainfall and temperature statistics at the local scale, associated with global climate variability and change, and to investigate the impact of the latter on coupled ocean�atmosphere modes. Our main project results consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling together with the development of associated software; new intermediate coupled models; a new methodology of inverse modeling for linking ICMs with observations and GCM simulations, called empirical mode reduction (EMR); and observational studies of decadal and multi-decadal natural climate variability, informed by ICM simulations. A particularly timely by-product of this work is an extensive study of clustering of cyclone tracks in the extratropical Atlantic and the western Tropical Pacific, with potential applications to predicting landfall.

M. Ghil (UCLA), PI; S. Kravtsov (UWM); A. W. Robertson (IRI); P. Smyth (UCI)

2008-10-14T23:59:59.000Z

455

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

456

Anthropogenic Aerosol Radiative Forcing in Asia Derived From Regional Models With Atmospheric and Aerosol Data Assimilation  

DOE Green Energy (OSTI)

A high-resolution estimate of monthly 3D aerosol solar heating rates and surface solar fluxes in Asia from 2001 to 2004 is described here. This product stems from an Asian aerosol assimilation project, in which a) the PNNL regional model bounded by the NCEP reanalyses was used to provide meteorology, b) MODIS and AERONET data were integrated for aerosol observations, c) the Iowa aerosol/chemistry model STEM-2K1 used the PNNL meteorology and assimilated aerosol observations, and d) 3D (X-Y-Z) aerosol simulations from the STEM-2K1 were used in the Scripps Monte-Carlo Aerosol Cloud Radiation (MACR) model to produce total and anthropogenic aerosol direct solar forcing for average cloudy skies. The MACR model and STEM both used the PNNL model resolution of 0.45º×0.4º in the horizontal and of 23 layers in the troposphere. The 2001–2004 averaged anthropogenic all-sky aerosol forcing is ?1.3 Wm-2 (TOA), +7.3 Wm-2 (atmosphere) and ?8.6 Wm-2 (surface) averaged in Asia (60?138°E & Eq. ?45°N). In the absence of AERONET SSA assimilation, absorbing aerosol concentration (especially BC aerosol) is much smaller, giving ?2.3 Wm-2 (TOA), +4.5 Wm-2 (atmosphere) and ?6.8 Wm-2 (surface), averaged in Asia. In the vertical, monthly forcing is mainly concentrated below 600hPa with maxima around 800hPa. Seasonally, low-level forcing is far larger in dry season than in wet season in South Asia, whereas the wet season forcing exceeds the dry season forcing in East Asia. The anthropogenic forcing in the present study is similar to that in Chung et al.’s [2005] in overall magnitude but the former offers fine-scale features and simulated vertical profiles. The interannual variability of the computed anthropogenic forcing is significant and extremely large over major emission outflow areas. In view of this, the present study’s estimate is within the implicated range of the 1999 INDOEX result. However, NCAR/CCSM3’s anthropogenic aerosol forcing is much smaller than the present study’s estimate at the surface, and is outside of what the INDOEX findings can support.

Chung, Chul Eddy; Ramanathan, V.; Carmichael, Gregory; Kulkarni, S.; Tang, Youhua; Adhikary, Bhupesh; Leung, Lai-Yung R.; Qian, Yun

2010-07-05T23:59:59.000Z

457

A General Interface between an Atmospheric General Circulation Model and Underlying Ocean and Land Surface Models: Delocalized Physics Scheme  

Science Conference Proceedings (OSTI)

In order to represent in a most adequate way the various feedback mechanisms that govern the atmosphere–ocean or atmosphere–surface couplings, a “delocalized physics” method is introduced, in which the subgrid-scale physical parameterizations of ...

Augustin Vintzileos; Robert Sadourny

1997-05-01T23:59:59.000Z

458

Modeling of Glass Making Processes for Improved Efficiency  

SciTech Connect

The overall goal of this project was to develop a high-temperature melt properties database with sufficient reliability to allow mathematical modeling of glass melting and forming processes for improved product quality, improved efficiency and lessened environmental impact. It was initiated by the United States glass industry through the NSF Industry/University Center for Glass Research (CGR) at Alfred University [1]. Because of their important commercial value, six different types/families of glass were studied: container, float, fiberglass (E- and wool-types), low-expansion borosilicate, and color TV panel glasses. CGR member companies supplied production-quality glass from all six families upon which we measured, as a function of temperature in the molten state, density, surface tension, viscosity, electrical resistivity, infrared transmittance (to determine high temperature radiative conductivity), non-Newtonian flow behavior, and oxygen partial pres sure. With CGR cost sharing, we also studied gas solubility and diffusivity in each of these glasses. Because knowledge of the compositional dependencies of melt viscosity and electrical resistivity are extremely important for glass melting furnace design and operation, these properties were studied more fully. Composition variations were statistically designed for all six types/families of glass. About 140 different glasses were then melted on a laboratory scale and their viscosity and electrical resistivity measured as a function of temperature. The measurements were completed in February 2003 and are reported on here. The next steps will be (1) to statistically analyze the compositional dependencies of viscosity and electrical resistivity and develop composition-property response surfaces, (2) submit all the data to CGR member companies to evaluate the usefulness in their models, and (3) publish the results in technical journals and most likely in book form.

Thomas P. Seward III

2003-03-31T23:59:59.000Z

459

SUPERBURST MODELS FOR NEUTRON STARS WITH HYDROGEN- AND HELIUM-RICH ATMOSPHERES  

SciTech Connect

Superbursts are rare day-long type I X-ray bursts due to carbon flashes on accreting neutron stars in low-mass X-ray binaries. They heat the neutron star envelope such that the burning of accreted hydrogen and helium becomes stable, and the common shorter X-ray bursts are quenched. Short bursts reappear only after the envelope cools down. We study multi-zone one-dimensional models of the neutron star envelope, in which we follow carbon burning during the superburst, and we include hydrogen and helium burning in the atmosphere above. We investigate the cases of both a solar-composition and a helium-rich atmosphere. This allows us to study for the first time a wide variety of thermonuclear burning behavior as well as the transitions between the different regimes in a self-consistent manner. For solar composition, burst quenching ends much sooner than previously expected. This is because of the complex interplay between the 3{alpha}, hot CNO, and CNO breakout reactions. Stable burning of hydrogen and helium transitions via marginally stable burning (mHz quasi-periodic oscillations) to less energetic bursts with short recurrence times. We find a short-lived bursting mode where weaker and stronger bursts alternate. Eventually the bursting behavior changes back to that of the pre-superburst bursts. Because of the scarcity of observations, this transition has not been directly detected after a superburst. Using the MINBAR burst catalog we identify the shortest upper limit on the quenching time for 4U 1636-536, and derive further constraints on the timescale on which bursts return.

Keek, L. [National Superconducting Cyclotron Laboratory, Department of Physics and Astronomy, and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Heger, A. [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); In 't Zand, J. J. M., E-mail: keek@nscl.msu.edu [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands)

2012-06-20T23:59:59.000Z

460

Evaluation of a Mesoscale Atmospheric Dispersion Modeling System with Observations from the 1980 Great Plains Mesoscale Tracer Field Experiment. Part I: Datasets and Meteorological Simulations  

Science Conference Proceedings (OSTI)

The Colorado State University mesoscale atmospheric dispersion (MAD) numerical modeling system, which consists of a prognostic mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model, has been used to simulate ...

Michael D. Moran; Roger A. Pielke

1996-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "improving atmospheric models" 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

POPDOSE-SR: A Routine Release Atmospheric Population Dose Model Used at SRS  

SciTech Connect

POPDOSE-SR is used to calculate dose to the surrounding Savannah River Site (SRS) population following routine releases of atmospheric radioactivity.

Simpkins, A.A.

2001-04-04T23:59:59.000Z

462

An Accurate Radiative Heating and Cooling Algorithm for Use in a Dynamical Model of the Middle Atmosphere  

Science Conference Proceedings (OSTI)

An infrared radiative heating and cooling algorithm designed to be used with dynamical models of the middle atmosphere is described. A Curtis matrix is used to compute cooling by the 15 and 10 ?m bands of carbon dioxide. Escape of radiation to ...

W. M. Wehrbein; C. B. Leovy

1982-07-01T23:59:59.000Z

463

Time-Mean Response over the Tropical Pacific to Increased C02 in a Coupled Ocean-Atmosphere Model  

Science Conference Proceedings (OSTI)

The time-mean response over the tropical Pacific region to a quadrupling Of CO2 is investigated using a global coupled ocean-atmosphere general circulation model. Tropical Pacific sea surface temperatures (SSTs) rise by about 4°–5°C. The zonal ...

Thomas R. Knutson; Syukuro Manabe

1995-09-01T23:59:59.000Z

464

Linear versus Nonlinear Filtering with Scale-Selective Corrections for Balanced Dynamics in a Simple Atmospheric Model  

Science Conference Proceedings (OSTI)

This paper investigates the role of the linear analysis step of the ensemble Kalman filters (EnKF) in disrupting the balanced dynamics in a simple atmospheric model and compares it to a fully nonlinear particle-based filter (PF). The filters have ...

Aneesh C. Subramanian; Ibrahim Hoteit; Bruce Cornuelle; Arthur J. Miller; Hajoon Song

2012-11-01T23:59:59.000Z

465

A Discrete Ordinate, Multiple Scattering, Radiative Transfer Model of the Venus Atmosphere from 0.1 to 260 ?m  

Science Conference Proceedings (OSTI)

The authors describe a new radiative transfer model of the Venus atmosphere (RTM) that includes optical properties from nine gases and four cloud modes between 0.1 and 260 ?m. A multiple-stream discrete ordinate flux solver is used to calculate ...

Christopher Lee; Mark Ian Richardson

2011-06-01T23:59:59.000Z

466

A Three-Dimensional Radiative Transfer Model to Investigate the Solar Radiation within a Cloudy Atmosphere. Part I: Spatial Effects  

Science Conference Proceedings (OSTI)

A new Monte Carlo–based three-dimensional (3D) radiative transfer model of high spectral and spatial resolution is presented. It is used to investigate the difference in broadband solar radiation absorption, top-of-the-atmosphere upwelling, and ...

William O’Hirok; Catherine Gautier

1998-06-01T23:59:59.000Z

467

Design and Critical Appraisal of an Accelerated Integration Procedure for Atmospheric GCM/Mixed-Layer Ocean Models  

Science Conference Proceedings (OSTI)

An accelerated integration procedure (AIP) is developed for the OSU atmospheric GCM/mixed-layer ocean model. In this AIP the depth of the mixed-layer ocean is reduced by an acceleration factor fe=12 from 60 m to 5 m and the length of a solar ...

Michael E. Schlesinger; Zong-Cl Zhao; Dean Vickers

1989-07-01T23:59:59.000Z

468

A Combined Local and Nonlocal Closure Model for the Atmospheric Boundary Layer. Part II: Application and Evaluation in a Mesoscale Meteorological Model  

Science Conference Proceedings (OSTI)

A new combined local and nonlocal closure atmospheric boundary layer model called the Asymmetric Convective Model, version 2, (ACM2) was described and tested in one-dimensional form and was compared with large-eddy simulations and field data in ...

Jonathan E. Pleim

2007-09-01T23:59:59.000Z

469

Reference model for software process improvement: a Brazilian experience  

Science Conference Proceedings (OSTI)

Recent research efforts about quality in the software area demonstrate that a concentrated effort is necessary to improve software process. Mainly in Brazil, there is an urge to enhance software processes performance aiming to improve the quality of ...

Ana Regina Rocha; Mariano Montoni; Gleison Santos; Sômulo Mafra; Sávio Figueiredo; Adriano Albuquerque; Paula Mian

2005-11-01T23:59:59.000Z

470

Modeling land-surface/atmosphere dynamics for CHAMMP. Progress report, August 1, 1992--31 July 1993  

SciTech Connect

Project progress is described on a DOE CHAMP project to model the land-surface/atmosphere coupling in a heterogeneous environment. This work is a collaboration between scientists at Iowa State University and the University of New Hampshire. Work has proceeded in two areas: baseline model coupling and data base development for model validation. The core model elements (land model, atmosphere model) have been ported to the Principal Investigator`s computing system and baseline coupling has commenced. The initial target data base is the set of observations from the FIFE field campaign, which is in the process of being acquired. For the remainder of the project period, additional data from the region surrounding the FIFE site and from other field campaigns will be acquired to determine how to best extrapolate results from the initial target region to the rest of the globe. In addition, variants of the coupled model will be used to perform experiments examining resolution requirements and coupling strategies for land-atmosphere coupling in a heterogeneous environment.

Gutowski, W.J. Jr.

1993-01-01T23:59:59.000Z

471

A New Formulation of the Spectral Energy Budget of the Atmosphere, with Application to Two High-Resolution General Circulation Models  

Science Conference Proceedings (OSTI)

A new formulation of the spectral energy budget of kinetic and available potential energies of the atmosphere is derived, with spherical harmonics as base functions. Compared to previous formulations, there are three main improvements: (i) the ...

Pierre Augier; Erik Lindborg

2013-07-01T23:59:59.000Z

472

Modeling the chemical kinetics of atmospheric plasma for cell treatment in a liquid solution  

Science Conference Proceedings (OSTI)

Low temperature atmospheric pressure plasmas have been known to be effective for living cell inactivation in a liquid solution but it is not clear yet which species are key factors for the cell treatment. Using a global model, we elucidate the processes through which pH level in the solution is changed from neutral to acidic after plasma exposure and key components with pH and air variation. First, pH level in a liquid solution is changed by He{sup +} and He(2{sup 1}S) radicals. Second, O{sub 3} density decreases as pH level in the solution decreases and air concentration decreases. It can be a method of removing O{sub 3} that causes chest pain and damages lung tissue when the density is very high. H{sub 2}O{sub 2}, HO{sub 2}, and NO radicals are found to be key factors for cell inactivation in the solution with pH and air variation.

Kim, H. Y.; Kang, S. K.; Lee, H. Wk. [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, H. W. [Medipl Corporation, Pohang 790-834 (Korea, Republic of); Kim, G. C. [Medipl Corporation, Pohang 790-834 (Korea, Republic of); Department of Oral Anatomy and Cell Biology, School of Dentistry, Pusan National University, Pusan 602-739 (Korea, Republic of); Lee, J. K. [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Medipl Corporation, Pohang 790-834 (Korea, Republic of)

2012-07-15T23:59:59.000Z

473

Computational Efficiency and Accuracy of Methods for Asynchronously Coupling Atmosphere-Ocean Climate Models. Part II: Testing with a Seasonal Cycle  

Science Conference Proceedings (OSTI)

The asynchronous coupling schemes used in the seasonal, coupled atmosphere–ocean general circulation models (A/O GCMs) of Manabe et al. 1979 and Washington et al. 1980 are tested in the seasonal, coupled atmosphere–ocean model of Harvey and ...

L. D. Danny Harvey

1986-01-01T23:59:59.000Z

474

he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study  

SciTech Connect

This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistryâ??s MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the marine atmosphere. Using these results, the mechanism was systematically reduced to maximize computational speed. Finally, the mechanism was coupled to the 3-mode modal aerosol version of the NCAR Community Atmosphere Model (CAM v3.6.33). Decadal-scale simulations with CAM v.3.6.33, were run both with and without reactive-halogen chemistry and with and without explicit treatment of particulate organic carbon in the marine aerosol source function. Simulated results were interpreted (1) to evaluate influences of marine aerosol production on the microphysical properties of aerosol populations and clouds over the ocean and the corresponding direct and indirect effects on radiative transfer; (2) atmospheric burdens of reactive halogen species and their impacts on O3, NOx, OH, DMS, and particulate non-sea-salt SO42-; and (3) the global production and influences of marine-derived particulate organic carbon. The model reproduced major characteristics of the marine aerosol system and demonstrated the potential sensitivity of global, decadal-scale climate metrics to multiphase marine-derived components of Earthâ??s troposphere. Due to the combined computational burden of the coupled system, the currently available computational resources were the limiting factor preventing the adequate statistical analysis of the overall impact that multiphase chemistry might have on climate-scale radiative transfer and climate.

Keene, William C. [University of Virginia] [University of Virginia; Long, Michael S. [University of Virginia] [University of Virginia

2013-05-20T23:59:59.000Z

475

An Evaluation of Two NEXRAD Wind Retrieval Methodologies and Their Use in Atmospheric Dispersion Models  

SciTech Connect

Two entirely different methods for retrieving 3-D fields of horizontal winds from NEXRAD radial velocities have been evaluated using radar wind profiler measurements to determine whether routine wind retrievals would be useful for atmospheric dispersion model applications. The first method uses a physical algorithm based on four-dimensional variational data assimilation and the second simpler method uses a statistical technique based on an analytic formulation of the background error covariance. Both methods can be run in near real time, but the simpler method executed about 2.5 times faster than the four-dimensional variational method. The observed multi-day and diurnal variations in wind speed and direction were reproduced by both methods within about 1.5 km of the ground in the vicinity of Oklahoma City during July 2003. However, wind retrievals overestimated the strength of the nighttime low-level jet by as much as 65%. The wind speeds and directions obtained from both methods were usually similar when compared to profiler measurements, and neither method out-performed the other statistically. Within a dispersion model framework, the 3-D wind fields and transport patterns were often better represented when the wind retrievals were included along with operational data. Despite uncertainties in the wind speed and direction obtained from the wind retrievals that is higher than from remote sensing radar wind profilers, the inclusion of the wind retrievals are likely to produce more realistic temporal variations in the winds aloft than would be obtained by interpolation using the available radiosondes, especially during rapidly changing synoptic and mesoscale conditions.

Fast, Jerome D.; Newsom, Rob K.; Allwine, K Jerry; Xu, Qin; Zhang, Pengfei; Copeland, Jeffrey H.; Sun, Jenny

2008-09-01T23:59:59.000Z

476

Atmospheric Aerosols  

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

measuring equipment Atmospheric Aerosols Atmospheric aerosol research at Berkeley Lab seeks to understand the air quality and climate impacts of particles in the atmosphere. On...

477

Improving Health Care Management Through the Use of Dynamic Simulation Modeling and Health Information Systems  

Science Conference Proceedings (OSTI)

To better understand the performance of hospital operations in response to IT-enabled improvement, this paper reports the results of a system dynamics model designed to improve core medical processes. Utilizing system dynamics modeling and emerging Health ... Keywords: Health Information Systems, Heath Care, Hospital Management, Process Improvement, System Dynamics

Daniel Goldsmith; Michael Siegel

2012-01-01T23:59:59.000Z

478

The Seasonal and Latitudinal Behavior of Trace Gases and O3 as Simulated by a Two-Dimensional Model of the Atmosphere  

Science Conference Proceedings (OSTI)

A two-dimensional zonal-mean model with parameterized dynamics and an advanced photochemical scheme is used to simulate the stratospheric distributions of atmospheric trace gases including ozone. The model calculates the distributions of 37 ...

Malcolm K. W. Ko; Nien Dak Sze; Mikhail Livshits; Michael B. McElroy; John A. Pyle

1984-08-01T23:59:59.000Z

479

On the Application of the Dynamic Smagorinsky Model to Large-Eddy Simulations of the Cloud-Topped Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

In this paper the dynamic Smagorinsky model originally developed for engineering flows is adapted for simulations of the cloud-topped atmospheric boundary layer in which an anelastic form of the governing equations is used. The adapted model ...

M. P. Kirkpatrick; A. S. Ackerman; D. E. Stevens; N. N. Mansour

2006-02-01T23:59:59.000Z

480

Data Assimilation of Satellite-Derived Heating Rates as Proxy Surface Wetness Data into a Regional Atmospheric Mesoscale Model. Part II: A Case Study  

Science Conference Proceedings (OSTI)

A satellite data assimilation method is applied which incorporates satellite-observed heating infrared rates into a mesoscale atmospheric model to retrieve model soil moisture. In a 3D case study, the method is successful at retrieving realistic ...

Andrew S. Jones; Ingrid C. Guch; Thomas H. Vonder Haar

1998-03-01T23:59:59.000Z

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481

Mechanisms of Low Cloud–Climate Feedback in Idealized Single-Column Simulations with the Community Atmospheric Model, Version 3 (CAM3)  

Science Conference Proceedings (OSTI)

This study investigates the physical mechanism of low cloud feedback in the Community Atmospheric Model, version 3 (CAM3) through idealized single-column model (SCM) experiments over the subtropical eastern oceans. Negative cloud feedback is ...

Minghua Zhang; Christopher Bretherton

2008-09-01T23:59:59.000Z

482

The Description of the Navy Operational Global Atmospheric Prediction System's Spectral Forecast Model  

Science Conference Proceedings (OSTI)

We present a description of the development of the spectral forecast components of the Navy Operational Global Atmospheric Prediction System (NOGAPS). The original system, called 3.0, was introduced in January 1988. New versions were introduced ...

Timothy F. Hogan; Thomas E. Rosmond

1991-08-01T23:59:59.000Z

483

A Multimoment Constrained Finite-Volume Model for Nonhydrostatic Atmospheric Dynamics  

Science Conference Proceedings (OSTI)

The two-dimensional nonhydrostatic compressible dynamical core for the atmosphere has been developed by using a new nodal-type high-order conservative method, the so-called multimoment constrained finite-volume (MCV) method. Different from the ...

Xingliang Li; Chungang Chen; Xueshun Shen; Feng Xiao

2013-04-01T23:59:59.000Z

484

Atmospheric Dispersion from Elevated Sources in an Urban Area: Comparison between Tracer Experiments and Model Calculations  

Science Conference Proceedings (OSTI)

Atmospheric dispersion experiments were carried out in the Copenhagen area under neutral and unstable conditions. The tracer sulphurhexafluoride was released without buoyancy from a tower at a height of 115 m and then collected at ground-level ...

Sven-Erik Gryning; Erik Lyck

1984-04-01T23:59:59.000Z

485

Impact of Land Model Calibration on Coupled Land-Atmosphere Prediction  

Science Conference Proceedings (OSTI)

Land-atmosphere (L-A) interactions play a critical role in determining the diurnal evolution of both planetary boundary layer (PBL) and land surface heat and moisture budgets, as well as controlling feedbacks with clouds and precipitation that ...

Joseph A. Santanello; Jr.; Sujay V. Kumar; Christa D. Peters-Lidard; Ken Harrison; Shujia Zhou

486

A Modeling and Observational Framework for Diagnosing Local Land–Atmosphere Coupling on Diurnal Time Scales  

Science Conference Proceedings (OSTI)

Land–atmosphere interactions play a critical role in determining the diurnal evolution of both planetary boundary layer (PBL) and land surface temperature and moisture states. The degree of coupling between the land surface and PBL in numerical ...

Joseph A. Santanello Jr.; Christa D. Peters-Lidard; Sujay V. Kumar; Charles Alonge; Wei-Kuo Tao

2009-06-01T23:59:59.000Z

487

A Scalable Spectral Element Eulerian Atmospheric Model (SEE-AM) for NWP: Dynamical Core Tests  

Science Conference Proceedings (OSTI)

A new dynamical core for numerical weather prediction (NWP) based on the spectral element method is presented. This paper represents a departure from previously published work on solving the atmospheric primitive equations in that the horizontal ...

Francis X. Giraldo; Thomas E. Rosmond

2004-01-01T23:59:59.000Z

488

Effects of Initial and Boundary Conditions of Mesoscale Models on Simulated Atmospheric Refractivity  

Science Conference Proceedings (OSTI)

Radar ducting is caused by sharp vertical changes in temperature and, especially, water vapor at the top of the atmospheric boundary layer, both of which are sensitive to variations in the underlying surface conditions, local mesoscale weather, ...

Changgui Wang; Damian Wilson; Tracy Haack; Peter Clark; Humphrey Lean; Robert Marshall

2012-01-01T23:59:59.000Z

489

A Wavelet–Based Approach for Atmospheric Pollution Modeling: Algorithm Development  

Science Conference Proceedings (OSTI)

A wavelet-based technique for numerical integration of species-conservation equations describing atmospheric pollutant transport and fate is described. This technique applies hexuplet families of spline-based biorthogonal wavelets using a quasi-...

Philip A. Ekstrom; Jeremy M. Hales

2000-09-01T23:59:59.000Z

490

A Total Turbulent Energy Closure Model for Neutrally and Stably Stratified Atmospheric Boundary Layers  

Science Conference Proceedings (OSTI)

This paper presents a turbulence closure for neutral and stratified atmospheric conditions. The closure is based on the concept of the total turbulent energy. The total turbulent energy is the sum of the turbulent kinetic energy and turbulent ...

Thorsten Mauritsen; Gunilla Svensson; Sergej S. Zilitinkevich; Igor Esau; Leif Enger; Branko Grisogono

2007-11-01T23:59:59.000Z

491

On the Use of Potential Vorticity Tendency Equations for Diagnosing Atmospheric Dynamics in Numerical Models  

Science Conference Proceedings (OSTI)

This study critically assesses potential vorticity (PV) tendency equations used for analyzing atmospheric convective systems. A generic PV tendency format is presented to provide a framework for comparing PV tendency equations, which isolates the ...

K. J. Tory; J. D. Kepert; J. A. Sippel; C. M. Nguyen

2012-03-01T23:59:59.000Z

492

Accelerated Iterative Method for Solving Steady Problems of Linearized Atmospheric Models  

Science Conference Proceedings (OSTI)

A new approach, referred to as the accelerated iterative method (AIM), is developed for obtaining steady atmospheric responses with a zonally varying basic state. The linear dynamical operator is divided into two parts, one associated with the ...

Masahiro Watanabe; Fei-fei Jin; Lin Pan

2006-12-01T23:59:59.000Z

493

The Effect of Serially Correlated Observation and Model Error on Atmospheric Data Assimilation  

Science Conference Proceedings (OSTI)

Observation error statistics are required in most atmospheric data assimilation systems. While observation errors are often assumed to be spatially correlated, serial correlations have received virtually no attention. In this article, the effect ...

Roger Daley

1992-01-01T23:59:59.000Z

494

Improved Modeling of Residential Air Conditioners and Heat Pumps for Energy Calculations  

SciTech Connect

This report presents improved air conditioner and heat pump modeling methods in the context of whole-building simulation tools, with the goal of enabling more accurate evaluation of cost effective equipment upgrade opportunities and efficiency improvements in residential buildings.

Cutler, D.; Winkler, J.; Kruis, N.; Christensen, C.; Brendemuehl, M.

2013-01-01T23:59:59.000Z

495

Gaseous dry deposition of atmospheric mercury: A comparison of two surface resistance models for deposition to semiarid vegetation  

Science Conference Proceedings (OSTI)

In the United States, atmospheric mercury (Hg) deposition, from regional and international sources, is the largest contributor to increased Hg concentrations in bodies of water leading to bioaccumulation of methyl mercury in fish. In this work, modeled dry deposition velocities (vd) for gaseous Hg are calculated using two surface resistance parameterizations found in the literature. The flux is then estimated as the product of the species concentration and modeled vd. The calculations utilize speciated atmospheric mercury concentrations measured during an annual monitoring campaign in southern Idaho. Gaseous elemental mercury (GEM) and reactive gaseous mercury (RGM) were monitored with Tekran models 2537A and 1130, respectively. Two anemometers collected meteorological data, including one fast-response three-dimensional sonic anemometer to measure turbulence parameters. For the flux calculation, three resistances are required to model the mechanisms that transport gaseous Hg from the atmosphere to the surface, with the surface resistance being the largest source of error. Results from two surface resistance models are presented. In particular, the downward flux is sensitive to the choice of model and input parameters such as seasonal category and mesophyll resistance. A comparison of annual GEM and RGM fluxes calculated using the two models shows good agreement for RGM (3.2% difference for annual deposition); however, for the low-solubility species of GEM, the models show a 64% difference in annual fluxes, with a range of 32% to 200% in seasonal fluxes. Results indicate the importance of understanding the diurnal variation of the physical processes modeled in the surface resistance parameterization for vd.

Heather A. Holmes; Eric R. Pardyjak; Kevin D. Perry; Michael L. Abbott

2011-07-01T23:59:59.000Z

496

Improvements to the EPA Industrial Source Complex Dispersion Model  

Science Conference Proceedings (OSTI)

Air quality models are a key component in determining air pollution control requirements. The Industrial Source Complex (ISC2) model is a steady-state Gaussian plume model that is used for modeling point, area, volume, and line sources. Since its ...

Dennis G. Atkinson; Desmond T. Bailey; John S. Irwin; Jawad S. Touma

1997-08-01T23:59:59.000Z

497

Improved  

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

Improved Improved cache performance in Monte Carlo transport calculations using energy banding A. Siegel a , K. Smith b , K. Felker c,∗ , P . Romano b , B. Forget b , P . Beckman c a Argonne National Laboratory, Theory and Computing Sciences and Nuclear Engineering Division b Massachusetts Institute of Technology, Department of Nuclear Science and Engineering c Argonne National Laboratory, Theory and Computing Sciences Abstract We present an energy banding algorithm for Monte Carlo (MC) neutral parti- cle transport simulations which depend on large cross section lookup tables. In MC codes, read-only cross section data tables are accessed frequently, ex- hibit poor locality, and are typically much too large to fit in fast memory. Thus, performance is often limited by long latencies to RAM, or by off-node communication latencies when the data footprint is very large and must be decomposed on

498

Simulation of the tropical Pacific climate with a coupled ocean - atmosphere general circulation model. Part II: Interannual variability  

Science Conference Proceedings (OSTI)

Two multiyear simulations with a coupled ocean-atmosphere general circulation model (GCM)-totaling 45 years-are used to investigate interannual variability at the equator. The model consists of the UCLA global atmospheric GCM coupled to the GFDL oceanic GCM, dynamically active over the tropical Pacific. Multichannel singular spectrum analysis along the equator identifies ENSO-like quasi-biennial (QB) and quasi-quadrennial (QQ) modes. Both consist of predominantly standing oscillations in sea surface temperature and zonal wind stress that peak in the central or east Pacific, accompanied by an oscillation in equatorial thermocline depth that is characterized by a phase shift of about 90{degrees} across the basin, with west leading east. Simulated interannual variability is weaker than observed in both simulations. One of these is dominated by the QB, the other by the QQ mode, although the two differ only in details of the surface-layer parameterizations. 42 refs., 19 figs., 2 tabs.

Robertson, A.W.; Ma, C.C.; Ghil, M. [Univ. of California, Los Angeles, CA (United States)] [and others

1995-05-01T23:59:59.000Z

499

Modeling the Direct and Indirect Effects of Atmospheric Aerosols on Tropical Cyclones  

E-Print Network (OSTI)

The direct and indirect effects of aerosols on the hurricane ‘Katrina’ have been investigated using the WRF model with a two-moment bulk microphysical scheme and modified Goddard shortwave radiation scheme. Simulations of the hurricane ‘Katrina’ are conducted under the three aerosol scenarios: 1) the clean case with an aerosol number concentration of 200 cm-1, 2) the polluted case with a number concentration of 1000 cm-1, and 3) the aerosol radiative effects (AR) case with same aerosol concentration as polluted case but with a modified shortwave radiation scheme. The polluted and AR cases have much larger amounts of cloud water and water vapor in troposphere, and the increased cloud water can freeze to produce ice water paths. A tropical cyclone in dirty and dusty air has active rainbands outside the eyewall due to aerosol indirect effects. The aerosol direct effect can lead to the suppressing of convection and weakening of updraft intensity by warming the troposphere and cooling the surface temperature. However, these thermal changes in atmosphere are concerned with the enhanced amounts of cloud hydrometeors and modification of downdraft and corresponding the low level winds in rainband regions. Thus, the AR case can produce the enhanced precipitation even in the weakest hurricane. When comparing the model performance between aerosol indirect and direct effect by ensemble experiments, the adjustment time of the circulation due to modification of the aerosol radiative forcing by aerosol layers may take a longer time than the hurricane lifetime, and the results from the simulated hurricane show that it is more sensitive to aerosol indirect effects which are related to the cloud microphysics process changes. From this aerosol study, we can suggest that aerosols can influence the cloudiness, precipitation, and intensity of hurricanes significantly, and there may be different results in the meso-scale convective clouds cases. The hurricane system is a large and complex convective system with enormous heating energy and moistures. Moreover, relationships between various hydrometeors in hurricane systems are difficult to isolate and thus, it needs further study with more realistic cloud microphysical processes, aerosol distributions, and parameterizations.

Lee, Keun-Hee

2011-12-01T23:59:59.000Z

500

Improving Concentration Measures Used for Evaluating Air Quality Models  

Science Conference Proceedings (OSTI)

An unfortunate difficulty in model evaluation is that the concentration measure that most models predict, namely the ensemble mean concentration under the plume centerline (or at some location relative to the plume centerline), cannot be measured ...

Russell F. Lee; John S. Irwin

1997-08-01T23:59:59.000Z