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Sample records for nested mesoscale model

  1. NESTED GRID MESOSCALE ATMOSPHERIC CHEMISTRY MODEL

    EPA Science Inventory

    A nested grid version of the Regional Acid Deposition Model (RADM) has been developed. he horizontal grid interval size of the nested model is 3 times smaller than that of RADM (80/3 km 26.7 km). herefore the nested model is better able to simulate mesoscale atmospheric processes...

  2. A nested-grid mesoscale numerical weather prediction model modified for Space Shuttle operational requirements

    NASA Technical Reports Server (NTRS)

    Kaplan, M. L.; Zack, J. W.; Wong, V. C.; Coats, G. D.

    1983-01-01

    A nested-grid mesoscale atmospheric simulation system (MASS) is tested over Florida for the case of intense seabreeze-induced convection. The goal of this modeling system is to provide real-time aviation weather support which is designed to fit local terminal operations such as those supporting NASA's STS. Results from a 58 km and a 14.5 km nested-grid simulation show that this version of the MASS is capable of simulating many of the basic characteristics of convective complexes during periods of relatively weak synoptic scale flow regimes. However, it is noted that extensive development work is required with nested-grid cumulus and planetary boundary layer parameterization schemes before many of the meso-beta scale features such as thunderstorm downdraft-produced bubble high pressure centers can be accurately simulated. After these schemes are properly tuned, MASS can be utilized to initialize microscale modeling systems.

  3. Implementation of wind turbine parameterizations in a mesoscale-LES nested model framework

    NASA Astrophysics Data System (ADS)

    Chow, Fotini; Marjanovic, Nikola; Mirocha, Jeffrey

    2014-11-01

    Wind turbine performance depends on weather conditions, local topography, and wind turbine spacing, among other factors. Atmospheric simulations can be used to predict wind energy production at increasingly higher resolutions. Turbine models placed within such simulations can be used to investigate turbine operation and performance. This work describes the implementation of generalized actuator disk (GAD) and line (GAL) models into the Weather Research and Forecasting (WRF) mesoscale atmospheric model. WRF can be used in a grid nested configuration starting from the mesoscale (~10 km resolution) and ending with fine scale resolutions (~1-10 m) suitable for large-eddy simulations (LES). At LES scales it becomes possible to resolve both the thrust and torque forces generated on turbines and imparted to the atmosphere using GAD and GAL models. Both models include real-time yaw and pitch control to respond to changing flow conditions. Here, the GAD and GAL are tested for idealized and real model configurations and compared to data from a wind farm. Comparisons are also made that help determine the importance of turbine blade tilt away from the tower and the inclusion of tower and turbine hub drag effects.

  4. Applying different spatial distribution and modelling concepts in three nested mesoscale catchments of Germany

    NASA Astrophysics Data System (ADS)

    Bongartz, K.

    Distributed, physically based river basin models are receiving increasing importance in integrated water resources management (IWRM) in Germany and in Europe, especially after the release of the new European Water Framework Directive (WFD). Applications in mesoscale catchments require an appropriate approach to represent the spatial distribution of related catchment properties such as land use, soil physics and topography by utilizing techniques of remote sensing and GIS analyses. The challenge is to delineate scale independent homogeneous modelling entities which, on the one hand may represent the dynamics of the dominant hydrological processes and, on the other hand can be derived from spatially distributed physiographical catchment properties. This scaling problem is tackled in this regional modelling study by applying the concept of hydrological response units (HRUs). In a nested catchment approach three different modelling conceptualisations are used to describe the runoff processes: (i) the topographic stream-segment-based HRU delineation proposed by Leavesley et al. [Precipitation-Runoff-Modelling-System, User’s Manual, Water Resource Investigations Report 83-4238, US Geological Survey, 1983]; (ii) the process based physiographic HRU-concept introduced by Flügel [Hydrol. Process. 9 (1995) 423] and (iii) an advanced HRU-concept adapted from (ii), which included the topographic topology of HRU-areas and the river network developed by Staudenraush [Eco Regio 8 (2000) 121]. The influence of different boundary conditions associated with changing the landuse classes, the temporal data resolution and the landuse scenarios were investigated. The mesoscale catchment of the river Ilm ( A∼895 km 2) in Thuringia, Germany, and the Precipitation-Runoff-Modelling-System (PRMS) were selected for this study. Simulations show that the physiographic based concept is a reliable method for modelling basin dynamics in catchments up to 200 km 2 whereas in larger catchments

  5. Data assimilation of a ten-day period during June 1993 over the Southern Great Plains Site using a nested mesoscale model

    SciTech Connect

    Dudhia, J.; Guo, Y.R.

    1996-04-01

    A goal of the Atmospheric Radiation Measurement (ARM) Program has been to obtain a complete representation of physical processes on the scale of a general circulation model (GCM) grid box in order to better parameterize radiative processes in these models. Since an observational network of practical size cannot be used alone to characterize the Cloud and Radiation Testbed (CART) site`s 3D structure and time development, data assimilation using the enhanced observations together with a mesoscale model is used to give a full 4D analysis at high resolution. The National Center for Atmospheric Research (NCAR)/Penn State Mesoscale Model (MM5) has been applied over a ten-day continuous period in a triple-nested mode with grid sizes of 60, 20 and 6.67 in. The outer domain covers the United States` 48 contiguous states; the innermost is a 480-km square centered on Lamont, Oklahoma. A simulation has been run with data assimilation using the Mesoscale Analysis and Prediction System (MAPS) 60-km analyses from the Forecast Systems Laboratory (FSL) of the National Ocean and Atmospheric Administration (NOAA). The nested domains take boundary conditions from and feed back continually to their parent meshes (i.e., they are two-way interactive). As reported last year, this provided a simulation of the basic features of mesoscale events over the CART site during the period 16-26 June 1993 when an Intensive Observation Period (IOP) was under way.

  6. Validation of mesoscale models

    NASA Technical Reports Server (NTRS)

    Kuo, Bill; Warner, Tom; Benjamin, Stan; Koch, Steve; Staniforth, Andrew

    1993-01-01

    The topics discussed include the following: verification of cloud prediction from the PSU/NCAR mesoscale model; results form MAPS/NGM verification comparisons and MAPS observation sensitivity tests to ACARS and profiler data; systematic errors and mesoscale verification for a mesoscale model; and the COMPARE Project and the CME.

  7. Acid rain: Mesoscale model

    NASA Technical Reports Server (NTRS)

    Hsu, H. M.

    1980-01-01

    A mesoscale numerical model of the Florida peninsula was formulated and applied to a dry, neutral atmosphere. The prospective use of the STAR-100 computer for the submesoscale model is discussed. The numerical model presented is tested under synoptically undisturbed conditions. Two cases, differing only in the direction of the prevailing geostrophic wind, are examined: a prevailing southwest wind and a prevailing southeast wind, both 6 m/sec at all levels initially.

  8. Mesoscale ocean dynamics modeling

    SciTech Connect

    mHolm, D.; Alber, M.; Bayly, B.; Camassa, R.; Choi, W.; Cockburn, B.; Jones, D.; Lifschitz, A.; Margolin, L.; Marsden, L.; Nadiga, B.; Poje, A.; Smolarkiewicz, P.; Levermore, D.

    1996-05-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The ocean is a very complex nonlinear system that exhibits turbulence on essentially all scales, multiple equilibria, and significant intrinsic variability. Modeling the ocean`s dynamics at mesoscales is of fundamental importance for long-time-scale climate predictions. A major goal of this project has been to coordinate, strengthen, and focus the efforts of applied mathematicians, computer scientists, computational physicists and engineers (at LANL and a consortium of Universities) in a joint effort addressing the issues in mesoscale ocean dynamics. The project combines expertise in the core competencies of high performance computing and theory of complex systems in a new way that has great potential for improving ocean models now running on the Connection Machines CM-200 and CM-5 and on the Cray T3D.

  9. Improving mesoscale QPF in regions of complex terrain using a fine-scaled nested model and satellite-retrieved data

    NASA Astrophysics Data System (ADS)

    Kuligowski, Robert Joseph

    2000-10-01

    Quantitative precipitation forecasting (QPF) has importance for a broad variety of applications, from agricultural and construction interests to flood forecasting. Both the accuracy and timeliness of QPF are crucial components in its usefulness, especially for hydrologic forecasting, but in general the present state of QPF is lacking in both areas. This thesis approaches QPF from a numerical weather prediction (NWP) model on two fronts. The first is to present a NWP model for predicting short-term precipitation at very fine scales (1-km) over regions with highly variable terrain, and an example from the Pocono Mountains in Pennsylvania is presented. The second is to improve the performance of the NWP model by using satellite data to estimate the initial fields of temperature and moisture used in the model. This use of satellite data has two steps. The first is to produce retrievals of temperature and moisture at individual points using an artificial neural network (ANN) trained on collocated satellite and radiosonde data. The second step is to us a fractal disaggregation scheme to re-scale the satellite images that are at three different horizontal resolutions to the fine spatial resolution of the NWP model. The results show that the fine-scale NWP model using the satellite- retrieved initial conditions has slightly better skill at predicting precipitation than a comparable model, but that the model variables not replaced with satellite- retrieved values still exert a significant influence on the model solution.

  10. Nesting Large-Eddy Simulations Within Mesoscale Simulations for Wind Energy Applications

    NASA Astrophysics Data System (ADS)

    Lundquist, J. K.; Mirocha, J. D.; Chow, F. K.; Kosovic, B.; Lundquist, K. A.

    2008-12-01

    With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES) account for complex terrain and resolve individual atmospheric eddies on length scales smaller than turbine blades. These small-domain high-resolution simulations are possible with a range of commercial and open- source software, including the Weather Research and Forecasting (WRF) model. In addition to "local" sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting that a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecating model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosoviæ (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Nesting large-eddy simulations within mesoscale simulations for wind energy applications

    SciTech Connect

    Lundquist, J K; Mirocha, J D; Chow, F K; Kosovic, B; Lundquist, K A

    2008-09-08

    With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES), which resolve individual atmospheric eddies on length scales smaller than turbine blades and account for complex terrain, are possible with a range of commercial and open-source software, including the Weather Research and Forecasting (WRF) model. In addition to 'local' sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting that a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecasting model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosovic (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain.

  12. Wind turbine parameterizations implemented in WRF mesoscale-LES nested simulations

    NASA Astrophysics Data System (ADS)

    Marjanovic, N.; Mirocha, J. D.; Chow, F. K.

    2014-12-01

    Atmospheric simulations can be used to predict wind energy production at increasingly higher resolutions, which can better capture boundary layer processes and topography. Wind turbine performance depends on several different factors including local topography, weather conditions, and turbine spacing. In this work, we implement and examine the performance of a generalized actuator disk model (GAD) and a generalized actuator line model (GAL) in the Weather Research and Forecasting (WRF) model, a mesoscale atmospheric model. The wind turbine parameterizations are designed for turbulence-resolving simulations, and are used within downscaled large-eddy simulations (LES) forced with mesoscale simulations and WRF's grid nesting capability. The GAD represents the effects of thrust and torque created by a wind turbine on the atmosphere within a disk representing the rotor swept area. The forces applied by the turbine blades on the atmosphere are parameterized using blade-element theory and the aerodynamic properties of the blades. The GAL tracks the location of the individual turbine blades and applies thrust and tangential forces at the temporal location of each blade instead of distributing the total force of all the blades over the actuator disk like the GAD does. This should in theory increase fidelity but carries higher computational cost (~10 m for GAD vs. ~1 m resolution for GAL). Both GAD and GAL models include real-time yaw and pitch control to respond realistically to changing flow conditions. Comparisons are also made to help determine the importance of turbine blade tilt away from the tower and the inclusion of the tower and turbine hub drag effects. Our implementations are designed to permit simulation of turbine wake effects and turbine/airflow interactions within a realistic atmospheric boundary layer flow field, including resolved turbulence, time-evolving mesoscale forcing, and real topography. This work was performed under the auspices of the U

  13. Mesoscale acid deposition modeling studies

    NASA Technical Reports Server (NTRS)

    Kaplan, Michael L.; Proctor, F. H.; Zack, John W.; Karyampudi, V. Mohan; Price, P. E.; Bousquet, M. D.; Coats, G. D.

    1989-01-01

    The work performed in support of the EPA/DOE MADS (Mesoscale Acid Deposition) Project included the development of meteorological data bases for the initialization of chemistry models, the testing and implementation of new planetary boundary layer parameterization schemes in the MASS model, the simulation of transport and precipitation for MADS case studies employing the MASS model, and the use of the TASS model in the simulation of cloud statistics and the complex transport of conservative tracers within simulated cumuloform clouds. The work performed in support of the NASA/FAA Wind Shear Program included the use of the TASS model in the simulation of the dynamical processes within convective cloud systems, the analyses of the sensitivity of microburst intensity and general characteristics as a function of the atmospheric environment within which they are formed, comparisons of TASS model microburst simulation results to observed data sets, and the generation of simulated wind shear data bases for use by the aviation meteorological community in the evaluation of flight hazards caused by microbursts.

  14. Nested-model approach to investigate climate change

    USGS Publications Warehouse

    Hay, Lauren E.; Leavesley, George H.

    1994-01-01

    Determination of the spatial and temporal distribution of precipitation in mountainous regions is critical for assessing the effects of climate variability on water resources in these regions. Potential effects of climate change on water resources in the Gunnison River basin of southwestern Colorado currently are being studied using a nested-model approach to disaggregate large-scale general circulation model output to account for smaller-scale processes. This paper presents a disaggregation technique in which scenarios of possible climate change will be developed by nesting a global general circulation model, a mesoscale climate model, a local orographic precipitation model, and a watershed model.

  15. Numerical Modelling of Mesoscale Atmospheric Dispersion.

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.

    Mesoscale atmospheric dispersion is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a more important role on the mesoscale, and horizontal dispersion can be enhanced and even dominated by vertical wind shear through either the simultaneous or delayed interaction of horizontal differential advection and vertical mixing over one or two diurnal periods. The CSU mesoscale atmospheric dispersion modelling system has been used in this study to simulate the transport and diffusion of a perfluorocarbon gas for episodic releases made during two North American mesoscale dispersion field experiments, the 1980 Great Plains tracer experiment and the 1983 Cross-Appalachian Tracer Experiment (CAPTEX). Ground -level and elevated tracer concentrations were measured out to distances of 600 km from the source in the first experiment and 1100 km in the second. The physiography of the two experimental domains was quite different, permitting isolation and examination of the roles of terrain forcing and differential advection in mesoscale atmospheric dispersion. Suites of numerical experiments of increasing complexity were carried out for both case studies. The experiments differed in the realism of their representation of both the synoptic-scale flow and the underlying terrain. The Great Plains nocturnal low-level jet played an important role in the first case while temporal changes in the synoptic -scale flow were very significant in the second case. The contributions of differential advection and mesoscale deformation to mesoscale dispersion dominated those of small-scale turbulent diffusion for both cases, and Pasquill's (1962) delayed-shear-enhancement mechanism for lateral dispersion was found to be particularly important. This study was also the first quantitative evaluation of the CSU mesoscale dispersion modelling system with

  16. Chemistry on the mesoscale: Modeling and measurement issues

    NASA Technical Reports Server (NTRS)

    Thompson, Anne; Pleim, John; Walcek, Christopher; Ching, Jason; Binkowski, Frank; Tao, Wei-Kuo; Dickerson, Russell; Pickering, Kenneth

    1993-01-01

    The topics covered include the following: Regional Acid Deposition Model (RADM) -- a coupled chemistry/mesoscale model; convection in RADM; unresolved issues for mesoscale modeling with chemistry -- nonprecipitating clouds; unresolved issues for mesoscale modeling with chemistry -- aerosols; tracer studies with Goddard Cumulus Ensemble Model (GCEM); field observations of trace gas transport in convection; and photochemical consequences of convection.

  17. Modeling mesoscale circulation of the Black Sea

    NASA Astrophysics Data System (ADS)

    Korotenko, K. A.

    2015-11-01

    An eddy-resolving (1/30)° version of the DieCAST low-dissipative model, adapted to the Black Sea circulation, is presented. Under mean climatological forcing, the model realistically reproduces major dominant large-scale and mesoscale structures of seasonal sea circulation, including the Rim Current, coastal anticyclonic eddies, mushroom currents, etc. Due to its extremely low dissipation and high resolution, the model makes it possible to trace the development of the baroclinic instability along the Turkish and Caucasian coasts, reproduce mesoscale structures generated by this mechanism, and assess the scales of these structures. The model also realistically reproduces short-term effects of bora winds on the evolution of subsurface layer structures.

  18. A history of mesoscale model development

    NASA Astrophysics Data System (ADS)

    Dudhia, Jimy

    2014-01-01

    The development of atmospheric mesoscale models from their early origins in the 1970's until the present day is described. Evolution has occurred in dynamical and physics representations in these models. The dynamics has had to change from hydrostatic to fully nonhydrostatic equations to handle the finer scales that have become possible in the last few decades with advancing computer power, which has enabled real-time forecasting to go to finer grid sizes. Meanwhile the physics has also become more sophisticated than the initial representations of the major processes associated with the surface, boundary layer, radiation, clouds and convection. As resolutions have become finer, mesoscale models have had to change paradigms associated with assumptions related to what is considered sub-grid scale needing parameterization, and what is resolved well enough to be explicitly handled by the dynamics. This first occurred with cumulus parameterization as real-time forecast models became able to represent individual updrafts, and is now starting to occur in the boundary layer as future forecast models may be able resolve individual thermals. Beyond that, scientific research has provided a greater understanding of detailed microphysical and land-surface processes that are important to aspects of weather prediction, and these parameterizations have been developing complexity at a steady rate. This paper can just give a perspective of these developments in the broad field of research associated with mesoscale atmospheric model development.

  19. DEVELOPMENT OF MESOSCALE AIR QUALITY SIMULATION MODELS. VOLUME 6. USER'S GUIDE TO MESOPAC (MESOSCALE METEOROLOGY PACKAGE)

    EPA Science Inventory

    MESOPAC is a mesoscale meteorological preprocessor program; it is designed to provide meteorological data to regional-scale air quality simulation models. Radiosonde data routinely available from National Weather Service (NWS) radiosonde ('upper air') and surface stations are use...

  20. Mesoscale modelling of PBX. Binder effects.

    NASA Astrophysics Data System (ADS)

    Milne, Alec; Dunnett, Jim; Bourne, Neil

    2007-06-01

    In earlier work we have studied aspects of shock to detonation transition and detonation structure in polymer bonded explosives on the scale of the largest grains (the mesoscale) to augment continuum models for these processes. Building blocks have been unreacted Hugoniots of mixtures, mapping from experiment (2D micrographs and 3D tomography) for accurate initial conditions and details of cavity collapse mechanisms as hot spots for ignition. Recently we have applied continuum mixture theory (multi-phase modelling) to dirty binder (the mixture of explosive crystal fines and binder that surrounds the large grains) and validated it for the unreacted Hugoniot of a range of UK explosives. In this paper we build on all of this work and report our progress in using continuum mixture theory to model the reactive behaviour of dirty binder. We begin by considering the binder on its own and then use this continuum mixture mode in conjunction with mesoscale representations of PBX. We consider PBX9501 and a UK PBX as examples. We identify the numerical modelling issues that have arisen, our current approaches and our plans for further development and testing.

  1. Probabilistic, meso-scale flood loss modelling

    NASA Astrophysics Data System (ADS)

    Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

    2016-04-01

    Flood risk analyses are an important basis for decisions on flood risk management and adaptation. However, such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments and even more for flood loss modelling. State of the art in flood loss modelling is still the use of simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood loss models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we demonstrate and evaluate the upscaling of the approach to the meso-scale, namely on the basis of land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany (Botto et al. submitted). The application of bagging decision tree based loss models provide a probability distribution of estimated loss per municipality. Validation is undertaken on the one hand via a comparison with eight deterministic loss models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official loss data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of loss estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation approach is that it inherently provides quantitative information about the uncertainty of the prediction. References: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64. Botto A, Kreibich H, Merz B, Schröter K (submitted) Probabilistic, multi-variable flood loss modelling on the meso-scale with BT-FLEMO. Risk Analysis.

  2. Numerical modelling of mesoscale atmospheric dispersion. (Volumes I and II)

    SciTech Connect

    Moran, M.D.

    1992-01-01

    Mesoscale atmospheric dispersion is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays an important role on the mesoscale, and horizontal dispersion can be enhanced and even dominated by vertical wind shear through either the simultaneous or delayed interaction of horizontal differential advection and vertical mixing. The CSU mesoscale atmospheric dispersion modelling system has been used in this study to simulate the transport and diffusion of a perfluorocarbon gas for episodic releases made during two mesoscale dispersion field experiments. The physiography of the two experimental domains was quite different, permitting isolation and examination of the roles of terrain forcing and differential advection in mesoscale atmospheric dispersion. Suites of numerical experiments of increasing complexity were carried out for both case studies. The experiments differed in the realism of their representation of both the synoptic-scale flow and the underlying terrain. The contributions of differential advection and mesoscale deformation to mesoscale dispersion dominated those of small-scale turbulent diffusion for both cases, and Pasquill's (1962) delayed-shear-enhancement mechanism for lateral dispersion was found to be particularly important. This study was also the first quantitative evaluation of the CSU mesoscale dispersion modelling system with episodic mesoscale dispersion field data. The modelling system showed considerable skill in predicting quantitative tracer-cloud characteristics such as peak concentration, maximum cloud width, arrival time, transit time, and crosswind integrated exposure. Model predictions also compared favorably with predictions made by a number of other mesoscale dispersion models for the same two case studies.

  3. Nested ocean models: Work in progress

    NASA Technical Reports Server (NTRS)

    Perkins, A. Louise

    1991-01-01

    The ongoing work of combining three existing software programs into a nested grid oceanography model is detailed. The HYPER domain decomposition program, the SPEM ocean modeling program, and a quasi-geostrophic model written in England are being combined into a general ocean modeling facility. This facility will be used to test the viability and the capability of two-way nested grids in the North Atlantic.

  4. Assessing nested hydrological and hydrochemical behaviour of a mesoscale catchment using continuous tracer data

    NASA Astrophysics Data System (ADS)

    Tetzlaff, D.; Waldron, S.; Brewer, M. J.; Soulsby, C.

    2007-04-01

    SummaryHigh resolution (15 min) continuous environmental tracer data (conductivity, pH and derived Gran alkalinity) were used to investigate the hydrological functioning of the 233 km 2 Feugh catchment in NE Scotland and two of its nested sub-catchments (42 km 2 and 1 km 2). Over the 2003-2004 hydrological year, a fine resolution Gran alkalinity time series was derived and indicated detailed and subtle changes in stream chemistry. Diurnal variation in alkalinity and flow were observed under low flow conditions, attributed to instream-respiration and riparian-evapotranspiration respectively. At high flows, abrupt threshold-like behaviour was evident during storm events as hydrological sources in the acidic surface horizons of the catchment soils replace groundwater as the dominant source of runoff. Using Gran alkalinity to define end-member compositions, chemically-based hydrograph separations revealed that as catchment scale increased, groundwater contributions to annual runoff increased from 52 ± 10%, to 67 ± 6%, to 70 ± 11%. This is consistent with previous mean residence times (MRT) estimated from weekly δ 18O data which respectively increased from 1.3-4.7 months -1 to 2.4-10.6 months -1 to 2.5-11.1 months -1. Linking continuous tracer data with GIS interpretation of landscape characteristics increased the sophistication of our conceptual model of catchment processes. Increasing dominance of responsive peaty soils leads to more saturation overland flow, increased flashiness of runoff, reduced groundwater recharge, reduced MRTs and more marked diurnal variations in flow, which drive concomitant difference in hydrochemistry. Conversely, increased cover of free-draining soils and aquifers in drift, reduced flashiness, increased groundwater contributions and increased MRTs. It is proposed that high resolution tracer data, in conjunction with other measurements defining catchment characteristics, represent a resource and challenge to modellers if models can be

  5. Evaluation of Mesoscale Model Phenomenological Verification Techniques

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred

    2006-01-01

    Forecasters at the Spaceflight Meteorology Group, 45th Weather Squadron, and National Weather Service in Melbourne, FL use mesoscale numerical weather prediction model output in creating their operational forecasts. These models aid in forecasting weather phenomena that could compromise the safety of launch, landing, and daily ground operations and must produce reasonable weather forecasts in order for their output to be useful in operations. Considering the importance of model forecasts to operations, their accuracy in forecasting critical weather phenomena must be verified to determine their usefulness. The currently-used traditional verification techniques involve an objective point-by-point comparison of model output and observations valid at the same time and location. The resulting statistics can unfairly penalize high-resolution models that make realistic forecasts of a certain phenomena, but are offset from the observations in small time and/or space increments. Manual subjective verification can provide a more valid representation of model performance, but is time-consuming and prone to personal biases. An objective technique that verifies specific meteorological phenomena, much in the way a human would in a subjective evaluation, would likely produce a more realistic assessment of model performance. Such techniques are being developed in the research community. The Applied Meteorology Unit (AMU) was tasked to conduct a literature search to identify phenomenological verification techniques being developed, determine if any are ready to use operationally, and outline the steps needed to implement any operationally-ready techniques into the Advanced Weather Information Processing System (AWIPS). The AMU conducted a search of all literature on the topic of phenomenological-based mesoscale model verification techniques and found 10 different techniques in various stages of development. Six of the techniques were developed to verify precipitation forecasts, one

  6. Numerical modelling of mesoscale atmospheric dispersion, volumes 1 and 2

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.

    Mesoscale atmospheric dispersion is more complicated than smaller scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a more important role on the mesoscale and horizontal dispersion can be enhanced and even dominated by vertical wind shear through either the simultaneous or delayed interaction of horizontal differential advection and vertical mixing over one or two diurnal periods. The CSU mesoscale atmospheric dispersion modeling system was used to simulate the transport and diffusion of a perfluorocarbon gas for episodic releases made during two North American mesoscale dispersion field experiments, the 1980 Great Plains tracer experiment and the 1983 Cross-Appalachian Tracer Experiment (CAPTEX). Ground-level and elevated tracer concentrations were measured out to distances of 600 km from the source in the first experiment and 1100 km in the second. The physiography of the two experimental domains was quite different, permitting isolation and examination of the roles of terrain forcing and differential advection in mesoscale atmospheric dispersion. Suites of numerical experiments of increasing complexity were carried out for both case studies. The experiments differed in the realism of their representation of both the synoptic-scale flow and the underlying terrain. The Great Plains nocturnal low-level jet played an important role in the first case while temporal changes in the synoptic-scale flow were very significant in the second case. The contributions of differential advection and mesoscale deformation to mesoscale dispersion dominated those of small-scale turbulent diffusion for both cases, and Pasquills delayed-shear-enhancement mechanism for lateral dispersion was found to be particularly important. The first quantitative evaluation of the CSU mesoscale dispersion modeling system with episodic mesoscale dispersion field data was presented

  7. Modeling Basin-scale Runoffs with Precipitation Data from Ground-based Observations and Mesoscale Simulations

    NASA Astrophysics Data System (ADS)

    Li, M.; Yang, M.; Soong, R.; Hwang, S.

    2002-12-01

    The purpose of this study is to investigate the applicability of distributed basin-scale runoff modeling, driven by rainfall data from either ground-based observations or mesoscale simulations, in response to typhoons invading Taiwan. Typhoons Herb (1996) and Zeb (1998) were selected for calibrating the runoff parameters reflecting the landuse conditions in the basin and evaluating the applicability of observed and simulated rainfall data toward runoff estimations, respectively. Upstream basins of Reservoir Shihmen with a drainage area of 764 km2 and Reservoir Feitsui with a drainage area of 303 km2 were the domains of interest in this preliminary study. Ground-based observations of both stream flows and station rainfalls were collected in an hourly resolution. The mesoscale model,MM5, simulation for Herb was conducted in 4-nested grids with the finest resolution of 2.2 km and 2-nested grids with the finest resolution of 15 km for Zeb, and the time resolution for both cases was 5 minutes. Accumulated total rain was accommodated with terrain elevation in MM5 simulations and station data to provide areal rainfall distributions. While the ground-based observations were sparse and incapable of correctly representing areal rainfall characteristics, the MM5 simulated data may introduce great uncertainties in basin-scale hydrological applications. The experience learned from this study is expected to provide an applicable approach with both ground-based observations and mesoscale simulations in basin-scale runoff computations.

  8. Evaluation of simple mesoscale models for use in TESS

    NASA Astrophysics Data System (ADS)

    Miller, R. J.; Sampson, C. R.

    1991-11-01

    Prediction of wind flow in a complex coastal environment is a challenging task that continues to be of interest to the U.S. Navy, specifically for use in the Tactical Environmental Support System (TESS). TESS is a computer workstation which provides environmental information for the Navy's tactical decision makers and is discussed in detail in Phegley and Crosiar (1991). According to Mass and Dempsey (1986), global and regional models have improved to the point where the adequately predict larger scale synoptic conditions; however, conversion of these forecasts into local and mesoscale weather is still a problem. One solution is to increase the resolution of a global or regional model to that desired for mesoscale prediction. The problem with this is that computational requirements for the model would far exceed the capability of TESS. Another solution is to run simple mesoscale models which use observations or output from the more complex models for initialization. Until recently, computational requirements of simple mesoscale models were beyond the capabilities of TESS. However, the TESS hardware has been upgraded to a system which is now capable of running simple mesoscale models.

  9. Modelling granite migration by mesoscale pervasive flow

    NASA Astrophysics Data System (ADS)

    Leitch, A. M.; Weinberg, R. F.

    2002-06-01

    Mesoscale pervasive magma migration leads to granite injection complexes, common in hot crustal terranes. Pervasive migration is limited by magma freezing when intruding cold country rock. Here, we explore numerically the feedback mechanism between magma intrusion and heating of the country rock, which allows younger intrusive batches to reach increasingly shallower/cooler levels. This process relies on the higher solidus temperature of a rock compared to that of its melt, once melt is segregated. We define the 'free-ride layer' as the region above the melt source, where magma may freely migrate because rock temperature is above melt solidus. The top of the free-ride layer, which corresponds to the melt solidus ( TS) isotherm, is at the 'limiting depth', zS. After magma passes through the free-ride layer, the magma 'front' is always at the limiting depth. We modeled the thickening and heating of the crust above the source as melt at its liquidus ( TL) intrudes it pervasively from below. We found that: (a) magma quickly warms crust below zS to about TL, forming a step in temperature at zS; (b) the front ( zS) moves up through the crust as more magma is intruded; (c) as magma is emplaced at the front, a mingled layer of about half magma half crust forms below it, so that the total rise of the front corresponds approximately to half of the thickness of magma added to the free-ride layer; (d) the rate of rise of the front depends on the temperature difference between crust and TL, and slows down as the magma front rises; (e) for most reasonable intrusion rates and volumes, the crust above zS feels little influence of the intrusion, because the diffusion time scale is much smaller than the rise rate of the front. In summary, pervasive migration is an efficient way of heating the lower to middle crust, and can result in an injection complex several kilometers thick, consisting of about half magma and half original crust.

  10. Recent Applications of Mesoscale Modeling to Nanotechnology and Drug Delivery

    SciTech Connect

    Maiti, A; Wescott, J; Kung, P; Goldbeck-Wood, G

    2005-02-11

    Mesoscale simulations have traditionally been used to investigate structural morphology of polymer in solution, melts and blends. Recently we have been pushing such modeling methods to important areas of Nanotechnology and Drug delivery that are well out of reach of classical molecular dynamics. This paper summarizes our efforts in three important emerging areas: (1) polymer-nanotube composites; (2) drug diffusivity through cell membranes; and (3) solvent exchange in nanoporous membranes. The first two applications are based on a bead-spring-based approach as encoded in the Dissipative Particle Dynamics (DPD) module. The last application used density-based Mesoscale modeling as implemented in the Mesodyn module.

  11. Mesoscale modeling of solute precipitation and radiation damage

    SciTech Connect

    Zhang, Yongfeng; Schwen, Daniel; Ke, Huibin; Bai, Xianming; Hales, Jason

    2015-09-01

    This report summarizes the low length scale effort during FY 2014 in developing mesoscale capabilities for microstructure evolution in reactor pressure vessels. During operation, reactor pressure vessels are subject to hardening and embrittlement caused by irradiation-induced defect accumulation and irradiation-enhanced solute precipitation. Both defect production and solute precipitation start from the atomic scale, and manifest their eventual effects as degradation in engineering-scale properties. To predict the property degradation, multiscale modeling and simulation are needed to deal with the microstructure evolution, and to link the microstructure feature to material properties. In this report, the development of mesoscale capabilities for defect accumulation and solute precipitation are summarized. Atomic-scale efforts that supply information for the mesoscale capabilities are also included.

  12. Budget study of a mesoscale convective system - Model simulation

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Simpson, Joanne; Mccumber, Michael

    1988-01-01

    A tropical squall-type cloud cluster is examined as an example of a mesoscale convective complex. The precipitation growth processes and air circulations that develop in the convective and stratiform regions are studied using a data set generated from a time-dependent numerical cloud model. The relationship of the stratiform region of the mesoscale convective complex is discussed. The vertical profiles of heating and drying are calculated. Comparisons are made between simulations with and without ice-phase microphysical processes and a simulation with forcing by weaker lifting at middle and upper levels.

  13. Massively parallel implementation of the Penn State/NCAR Mesoscale Model

    SciTech Connect

    Foster, I.; Michalakes, J.

    1992-01-01

    Parallel computing promises significant improvements in both the raw speed and cost performance of mesoscale atmospheric models. On distributed-memory massively parallel computers available today, the performance of a mesoscale model will exceed that of conventional supercomputers; on the teraflops machines expected within the next five years, performance will increase by several orders of magnitude. As a result, scientists will be able to consider larger problems, more complex model processes, and finer resolutions. In this paper. we report on a project at Argonne National Laboratory that will allow scientists to take advantage of parallel computing technology. This Massively Parallel Mesoscale Model (MPMM) will be functionally equivalent to the Penn State/NCAR Mesoscale Model (MM). In a prototype study, we produced a parallel version of MM4 using a static (compile-time) coarse-grained patch'' decomposition. This code achieves one-third the performance of a one-processor CRAY Y-MP on twelve Intel 1860 microprocessors. The current version of MPMM is based on all MM5 and uses a more fine-grained approach, decomposing the grid as finely as the mesh itself allows so that each horizontal grid cell is a parallel process. This will allow the code to utilize many hundreds of processors. A high-level language for expressing parallel programs is used to implement communication strearns between the processes in a way that permits dynamic remapping to the physical processors of a particular parallel computer. This facilitates load balancing, grid nesting, and coupling with graphical systems and other models.

  14. Massively parallel implementation of the Penn State/NCAR Mesoscale Model

    SciTech Connect

    Foster, I.; Michalakes, J.

    1992-12-01

    Parallel computing promises significant improvements in both the raw speed and cost performance of mesoscale atmospheric models. On distributed-memory massively parallel computers available today, the performance of a mesoscale model will exceed that of conventional supercomputers; on the teraflops machines expected within the next five years, performance will increase by several orders of magnitude. As a result, scientists will be able to consider larger problems, more complex model processes, and finer resolutions. In this paper. we report on a project at Argonne National Laboratory that will allow scientists to take advantage of parallel computing technology. This Massively Parallel Mesoscale Model (MPMM) will be functionally equivalent to the Penn State/NCAR Mesoscale Model (MM). In a prototype study, we produced a parallel version of MM4 using a static (compile-time) coarse-grained ``patch`` decomposition. This code achieves one-third the performance of a one-processor CRAY Y-MP on twelve Intel 1860 microprocessors. The current version of MPMM is based on all MM5 and uses a more fine-grained approach, decomposing the grid as finely as the mesh itself allows so that each horizontal grid cell is a parallel process. This will allow the code to utilize many hundreds of processors. A high-level language for expressing parallel programs is used to implement communication strearns between the processes in a way that permits dynamic remapping to the physical processors of a particular parallel computer. This facilitates load balancing, grid nesting, and coupling with graphical systems and other models.

  15. Driving Mesoscale Processes with Global Data Assimilative Models (Invited)

    NASA Astrophysics Data System (ADS)

    Bust, G. S.; Comberiate, J.; Datta-Barua, S.

    2013-12-01

    Global large scale ionosphere-thermosphere (IT) data assimilation methods have evolved to the point where they are able to estimate several IT state variables simultaneously over the entire globe.The large scale state variables estimated by data assimilative techniques can then be used to drive physical models of mesoscale and small scale processes. This allows for the possibility of being able to accurately predict mesoscale and small scale processes and structures from knowledge of the large scale driving physics. However, the accuracy of any such predictions will depend a) upon the accuracy of the estimated large scale state variables from data assimilation as well as b) the accuracy of the mesoscale and small scale models. In this presentation, we will focus upon the current capability of the data assimilation models IDA4D and EMPIRE to accurately estimate large scale IT state variables at equatorial latitudes. We will then discuss how these large scale state variables can be used to drive mesoscale models of the equatorial ionosphere and thermosphere. Results will be presented of large scale estimates of equatorial electron density and electric potential from analysis of IDA4D/EMPIRE and ingestion of C/NOFS observations

  16. Assimilation of GOES Land Surface Data into a Mesoscale Models

    NASA Technical Reports Server (NTRS)

    Lapenta, William M.; Suggs, Ron; McNider, Richard T.; Jedlovec, Gary; Dembek, Scott; Goodman, H. Michael (Technical Monitor)

    2001-01-01

    A technique has been developed for assimilating Geostationary Operational Environmental Satellite (GOES)-derived skin temperature tendencies and insolation into the surface energy budget equation of a mesoscale model so that the simulated rate of temperature change closely agrees with the satellite observations. A critical assumption of the technique is that the availability of moisture (either from the soil or vegetation) is the least known term in the model's surface energy budget. Therefore, the simulated latent heat flux, which is a function of surface moisture availability, is adjusted based upon differences between the modeled and satellite-observed skin temperature tendencies. An advantage of this technique is that satellite temperature tendencies are assimilated in an energetically consistent manner that avoids energy imbalances and surface stability problems that arise from direct assimilation of surface shelter temperatures. The fact that the rate of change of the satellite skin temperature is used rather than the absolute temperature means that sensor calibration is not as critical. The assimilation technique has been applied to the Oklahoma-Kansas region during the spring-summer 2000 time period when dynamic changes in vegetation cover occur. In April, central Oklahoma is characterized by large NDVI associated with winter wheat while surrounding areas are primarily rangeland with lower NDVI. In July the vegetation pattern reverses as the central wheat area changes to low NDVI due to harvesting and the surrounding rangeland is greener than it was in April. The goal of this study is to determine if assimilating satellite land surface data can improve simulation of the complex spatial distribution of surface energy and water fluxes across this region. The PSU/NCAR NM5 V3 system is used in this study. The grid configuration consists of a 36-km CONUS domain and a 12-km nest over the area of interest. Bulk verification statistics (BIAS and RMSE) of surface

  17. Numerical Model Studies of the Martian Mesoscale Circulations

    NASA Technical Reports Server (NTRS)

    Segal, Moti; Arritt, Raymond W.

    1997-01-01

    The study objectives were to evaluate by numerical modeling various possible mesoscale circulation on Mars and related atmospheric boundary layer processes. The study was in collaboration with J. Tillman of the University of Washington (who supported the study observationally). Interaction has been made with J. Prusa of Iowa State University in numerical modeling investigation of dynamical effects of topographically-influenced flow. Modeling simulations included evaluations of surface physical characteristics on: (i) the Martian atmospheric boundary layer and (ii) their impact on thermally and dynamically forced mesoscale flows. Special model evaluations were made in support of selection of the Pathfinder landing sites. J. Tillman's finding of VL-2 inter-annual temperature difference was followed by model simulations attempting to point out the forcing for this feature. Publication of the results in the reviewed literature in pending upon completion of the manuscripts in preparation as indicated later.

  18. Mesoscale Modeling of LX-17 Under Isentropic Compression

    SciTech Connect

    Springer, H K; Willey, T M; Friedman, G; Fried, L E; Vandersall, K S; Baer, M R

    2010-03-06

    Mesoscale simulations of LX-17 incorporating different equilibrium mixture models were used to investigate the unreacted equation-of-state (UEOS) of TATB. Candidate TATB UEOS were calculated using the equilibrium mixture models and benchmarked with mesoscale simulations of isentropic compression experiments (ICE). X-ray computed tomography (XRCT) data provided the basis for initializing the simulations with realistic microstructural details. Three equilibrium mixture models were used in this study. The single constituent with conservation equations (SCCE) model was based on a mass-fraction weighted specific volume and the conservation of mass, momentum, and energy. The single constituent equation-of-state (SCEOS) model was based on a mass-fraction weighted specific volume and the equation-of-state of the constituents. The kinetic energy averaging (KEA) model was based on a mass-fraction weighted particle velocity mixture rule and the conservation equations. The SCEOS model yielded the stiffest TATB EOS (0.121{micro} + 0.4958{micro}{sup 2} + 2.0473{micro}{sup 3}) and, when incorporated in mesoscale simulations of the ICE, demonstrated the best agreement with VISAR velocity data for both specimen thicknesses. The SCCE model yielded a relatively more compliant EOS (0.1999{micro}-0.6967{micro}{sup 2} + 4.9546{micro}{sup 3}) and the KEA model yielded the most compliant EOS (0.1999{micro}-0.6967{micro}{sup 2}+4.9546{micro}{sup 3}) of all the equilibrium mixture models. Mesoscale simulations with the lower density TATB adiabatic EOS data demonstrated the least agreement with VISAR velocity data.

  19. ROCKY MOUNTAIN ACID DEPOSITION MODEL ASSESSMENT: ACID RAIN MOUNTAIN MESOSCALE MODEL (ARM3)

    EPA Science Inventory

    The Acid Rain Mountain Mesoscale Model (ARM3) is a mesoscale acid deposition/air quality model that was developed for calculating incremental acid deposition (sulfur and nitrogen species) and pollutant concentration impacts in complex terrain. The model was set up for operation w...

  20. Mesoscale structures in the Subarctic Seas - observations and modelling

    NASA Astrophysics Data System (ADS)

    Walczowski, W.; Maslowski, W.

    2003-04-01

    Scientists from IO PAS have investigated the sub-arctic seas since 1989. In this study we present data collected by the IO PAS in contribution to VEINS project as well as from the other cruises conducted by R.V. Oceania in the Barents, Norwegian and Greenland seas. Observed mesoscale structures will be compared with results from two high-resolution models of the Pan-Arctic region forced with realistic atmospheric fields. The first model is configured at 1/6°(~18 km) and 30-layer grid and the second at 1/12° (~9 km) and 45-layer grid. Both models are developed at the Naval Postgraduate School, Monterey. Based on in situ measurements and model output, we specify regions of high mesoscale activity, which exist mainly along the Barents slope, in the area west of Spitsbergen and along the Arctic Front, separating water of Atlantic origin from the Greenland Sea Gyre. A comparison between current patterns, total kinetic energy (TKE) and eddy kinetic energy (EKE) calculated from the models and from in situ data will be presented. We will analyse observed mesoscale structures including frontal meanders and intrusions, cyclonic and anticyclonic eddies, and dense water plumes. Selected phenomena will be compared with modelled structures. Investigations of the Arctic Front show that mesoscale eddies and intrusions play an important role in the cross-frontal volume, salt and heat exchanges. Anticyclonic eddies originating from the frontal meanders carry considerable volume of Atlantic Water into the Greenland Sea. The transport of Atlantic Water from the Norwegian Sea into the Greenland Sea Gyre will be analysed based on field data and eddy-permitting model output. Anticyclonic eddies originating to the west of Spitsbergen play an important role in the recirculation of Atlantic Water in Fram Strait. Observed and modelled processes and pathways of the recirculation of Atlantic Water will be presented.

  1. Estimation of Eddy Dissipation Rates from Mesoscale Model Simulations

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.

    2012-01-01

    The Eddy Dissipation Rate is an important metric for representing the intensity of atmospheric turbulence and is used as an input parameter for predicting the decay of aircraft wake vortices. In this study, the forecasts of eddy dissipation rates obtained from the current state-of-the-art mesoscale model are evaluated for terminal area applications. The Weather Research and Forecast mesoscale model is used to simulate the planetary boundary layer at high horizontal and vertical mesh resolutions. The Bougeault-Lacarrer and the Mellor-Yamada-Janji schemes implemented in the Weather Research and Forecast model are evaluated against data collected during the National Aeronautics and Space Administration s Memphis Wake Vortex Field Experiment. Comparisons with other observations are included as well.

  2. RSL: A parallel Runtime System Library for regional atmospheric models with nesting

    SciTech Connect

    Michalakes, J.G.

    1997-08-01

    RSL is a parallel runtime system library developed at Argonne National Laboratory that is tailored to regular-grid atmospheric models with mesh refinement in the form of two-way interacting nested grids. RSL provides high-level stencil and interdomain communication, irregular domain decomposition, automatic local/global index translation, distributed I/O, and dynamic load balancing. RSL was used with Fortran90 to parallelize a well-known and widely used regional weather model, the Penn State/NCAR Mesoscale model.

  3. Animal Models and Integrated Nested Laplace Approximations

    PubMed Central

    Holand, Anna Marie; Steinsland, Ingelin; Martino, Sara; Jensen, Henrik

    2013-01-01

    Animal models are generalized linear mixed models used in evolutionary biology and animal breeding to identify the genetic part of traits. Integrated Nested Laplace Approximation (INLA) is a methodology for making fast, nonsampling-based Bayesian inference for hierarchical Gaussian Markov models. In this article, we demonstrate that the INLA methodology can be used for many versions of Bayesian animal models. We analyze animal models for both synthetic case studies and house sparrow (Passer domesticus) population case studies with Gaussian, binomial, and Poisson likelihoods using INLA. Inference results are compared with results using Markov Chain Monte Carlo methods. For model choice we use difference in deviance information criteria (DIC). We suggest and show how to evaluate differences in DIC by comparing them with sampling results from simulation studies. We also introduce an R package, AnimalINLA, for easy and fast inference for Bayesian Animal models using INLA. PMID:23708299

  4. A simple generative model of the mouse mesoscale connectome

    PubMed Central

    Henriksen, Sid; Pang, Rich; Wronkiewicz, Mark

    2016-01-01

    Recent technological advances now allow for the collection of vast data sets detailing the intricate neural connectivity patterns of various organisms. Oh et al. (2014) recently published the most complete description of the mouse mesoscale connectome acquired to date. Here we give an in-depth characterization of this connectome and propose a generative network model which utilizes two elemental organizational principles: proximal attachment ‒ outgoing connections are more likely to attach to nearby nodes than to distant ones, and source growth ‒ nodes with many outgoing connections are likely to form new outgoing connections. We show that this model captures essential principles governing network organization at the mesoscale level in the mouse brain and is consistent with biologically plausible developmental processes. DOI: http://dx.doi.org/10.7554/eLife.12366.001 PMID:26978793

  5. Functional Error Models to Accelerate Nested Sampling

    NASA Astrophysics Data System (ADS)

    Josset, L.; Elsheikh, A. H.; Demyanov, V.; Lunati, I.

    2014-12-01

    The main challenge in groundwater problems is the reliance on large numbers of unknown parameters with wide rage of associated uncertainties. To translate this uncertainty to quantities of interest (for instance the concentration of pollutant in a drinking well), a large number of forward flow simulations is required. To make the problem computationally tractable, Josset et al. (2013, 2014) introduced the concept of functional error models. It consists in two elements: a proxy model that is cheaper to evaluate than the full physics flow solver and an error model to account for the missing physics. The coupling of the proxy model and the error models provides reliable predictions that approximate the full physics model's responses. The error model is tailored to the problem at hand by building it for the question of interest. It follows a typical approach in machine learning where both the full physics and proxy models are evaluated for a training set (subset of realizations) and the set of responses is used to construct the error model using functional data analysis. Once the error model is devised, a prediction of the full physics response for a new geostatistical realization can be obtained by computing the proxy response and applying the error model. We propose the use of functional error models in a Bayesian inference context by combining it to the Nested Sampling (Skilling 2006; El Sheikh et al. 2013, 2014). Nested Sampling offers a mean to compute the Bayesian Evidence by transforming the multidimensional integral into a 1D integral. The algorithm is simple: starting with an active set of samples, at each iteration, the sample with the lowest likelihood is kept aside and replaced by a sample of higher likelihood. The main challenge is to find this sample of higher likelihood. We suggest a new approach: first the active set is sampled, both proxy and full physics models are run and the functional error model is build. Then, at each iteration of the Nested

  6. Mesoscale modeling of metal-loaded high explosives

    SciTech Connect

    Bdzil, John Bohdan; Lieberthal, Brandon; Srewart, Donald S

    2010-01-01

    We describe a 3D approach to modeling multi-phase blast explosive, which is primarily condensed explosive by volume with inert embedded particles. These embedded particles are uniform in size and placed on the array of a regular lattice. The asymptotic theory of detonation shock dynamics governs the detonation shock propagation in the explosive. Mesoscale hydrodynamic simulations are used to show how the particles are compressed, deformed, and accelerated by the high-speed detonation products flow.

  7. Anisotropic Mesoscale Eddy Transport in Ocean General Circulation Models

    NASA Astrophysics Data System (ADS)

    Reckinger, S. J.; Fox-Kemper, B.; Bachman, S.; Bryan, F.; Dennis, J.; Danabasoglu, G.

    2014-12-01

    Modern climate models are limited to coarse-resolution representations of large-scale ocean circulation that rely on parameterizations for mesoscale eddies. The effects of eddies are typically introduced by relating subgrid eddy fluxes to the resolved gradients of buoyancy or other tracers, where the proportionality is, in general, governed by an eddy transport tensor. The symmetric part of the tensor, which represents the diffusive effects of mesoscale eddies, is universally treated isotropically in general circulation models. Thus, only a single parameter, namely the eddy diffusivity, is used at each spatial and temporal location to impart the influence of mesoscale eddies on the resolved flow. However, the diffusive processes that the parameterization approximates, such as shear dispersion, potential vorticity barriers, oceanic turbulence, and instabilities, typically have strongly anisotropic characteristics. Generalizing the eddy diffusivity tensor for anisotropy extends the number of parameters to three: a major diffusivity, a minor diffusivity, and the principal axis of alignment. The Community Earth System Model (CESM) with the anisotropic eddy parameterization is used to test various choices for the newly introduced parameters, which are motivated by observations and the eddy transport tensor diagnosed from high resolution simulations. Simply setting the ratio of major to minor diffusivities to a value of five globally, while aligning the major axis along the flow direction, improves biogeochemical tracer ventilation and reduces global temperature and salinity biases. These effects can be improved even further by parameterizing the anisotropic transport mechanisms in the ocean.

  8. Development and analysis of prognostic equations for mesoscale kinetic energy and mesoscale (subgrid scale) fluxes for large-scale atmospheric models

    NASA Technical Reports Server (NTRS)

    Avissar, Roni; Chen, Fei

    1993-01-01

    Generated by landscape discontinuities (e.g., sea breezes) mesoscale circulation processes are not represented in large-scale atmospheric models (e.g., general circulation models), which have an inappropiate grid-scale resolution. With the assumption that atmospheric variables can be separated into large scale, mesoscale, and turbulent scale, a set of prognostic equations applicable in large-scale atmospheric models for momentum, temperature, moisture, and any other gaseous or aerosol material, which includes both mesoscale and turbulent fluxes is developed. Prognostic equations are also developed for these mesoscale fluxes, which indicate a closure problem and, therefore, require a parameterization. For this purpose, the mean mesoscale kinetic energy (MKE) per unit of mass is used, defined as E-tilde = 0.5 (the mean value of u'(sub i exp 2), where u'(sub i) represents the three Cartesian components of a mesoscale circulation (the angle bracket symbol is the grid-scale, horizontal averaging operator in the large-scale model, and a tilde indicates a corresponding large-scale mean value). A prognostic equation is developed for E-tilde, and an analysis of the different terms of this equation indicates that the mesoscale vertical heat flux, the mesoscale pressure correlation, and the interaction between turbulence and mesoscale perturbations are the major terms that affect the time tendency of E-tilde. A-state-of-the-art mesoscale atmospheric model is used to investigate the relationship between MKE, landscape discontinuities (as characterized by the spatial distribution of heat fluxes at the earth's surface), and mesoscale sensible and latent heat fluxes in the atmosphere. MKE is compared with turbulence kinetic energy to illustrate the importance of mesoscale processes as compared to turbulent processes. This analysis emphasizes the potential use of MKE to bridge between landscape discontinuities and mesoscale fluxes and, therefore, to parameterize mesoscale fluxes

  9. Computational Modeling of Heterogeneous Reactive Materials at the Mesoscale

    NASA Astrophysics Data System (ADS)

    Baer, Mel R.

    1999-06-01

    Nearly all energetic materials, including explosives, pyrotechnics, propellants and intermetallics are heterogeneous and typically consist of a mixture of crystalline constituents and binders. These materials exhibit distinctly different thermal/mechanical/chemical behavior than pure materials because microstructure introduces internal boundary effects at the mesoscale. For example, the threshold to reaction is known to be greatly influenced by changes in crystal morphology, size, defect content and particle distribution. Much of current work in computational modeling describes macroscale behavior based on continuum theory or microscopic/atomistic behavior using molecular dynamics methods. The mesoscale has not been as extensively studied yet it is the level that bridges continuum and atomistic scales. Shock physics analysis can now take advantage of new parallel computing machines to provide improved resolution of shock processes at the mesoscale. This presentation discusses three-dimensional numerical simulations of shock impact on a realistic ensemble of crystalline grains. Detailed wave fields are resolved including the effects of material strength, thermal dissipation and reaction. Numerical simulations demonstrate that rapid material distortion occurs at crystal boundaries and the localization of energy produces hot-spots due to the effects of shock focusing and plastic work as material flows into interstitial regions. These studies provide new insights into the micromechanical behavior of heterogeneous energetic materials strongly suggesting that initiation and reaction of shocked heterogeneous materials involve states distinctly different from single jump states. The recent enhancements in numerical modeling due to massively-parallel computing pose new challenges for the development of novel experimental capabilities that can provide the detailed information of appropriate material descriptions and interface conditions at the mesoscale.

  10. Adaptation of Mesoscale Weather Models to Local Forecasting

    NASA Technical Reports Server (NTRS)

    Manobianco, John T.; Taylor, Gregory E.; Case, Jonathan L.; Dianic, Allan V.; Wheeler, Mark W.; Zack, John W.; Nutter, Paul A.

    2003-01-01

    Methodologies have been developed for (1) configuring mesoscale numerical weather-prediction models for execution on high-performance computer workstations to make short-range weather forecasts for the vicinity of the Kennedy Space Center (KSC) and the Cape Canaveral Air Force Station (CCAFS) and (2) evaluating the performances of the models as configured. These methodologies have been implemented as part of a continuing effort to improve weather forecasting in support of operations of the U.S. space program. The models, methodologies, and results of the evaluations also have potential value for commercial users who could benefit from tailoring their operations and/or marketing strategies based on accurate predictions of local weather. More specifically, the purpose of developing the methodologies for configuring the models to run on computers at KSC and CCAFS is to provide accurate forecasts of winds, temperature, and such specific thunderstorm-related phenomena as lightning and precipitation. The purpose of developing the evaluation methodologies is to maximize the utility of the models by providing users with assessments of the capabilities and limitations of the models. The models used in this effort thus far include the Mesoscale Atmospheric Simulation System (MASS), the Regional Atmospheric Modeling System (RAMS), and the National Centers for Environmental Prediction Eta Model ( Eta for short). The configuration of the MASS and RAMS is designed to run the models at very high spatial resolution and incorporate local data to resolve fine-scale weather features. Model preprocessors were modified to incorporate surface, ship, buoy, and rawinsonde data as well as data from local wind towers, wind profilers, and conventional or Doppler radars. The overall evaluation of the MASS, Eta, and RAMS was designed to assess the utility of these mesoscale models for satisfying the weather-forecasting needs of the U.S. space program. The evaluation methodology includes

  11. Mesoscale constitutive modeling of magnetic dispersions.

    PubMed

    Bhandar, Anand S; Wiest, John M

    2003-01-15

    A constitutive model for dispersions of acicular magnetic particles has been developed by modeling the particles as rigid dumbbells dispersed in a solvent. The effects of Brownian motion, anisotropic hydrodynamic drag, a steric force in the form of the Maier-Saupe potential, and, most importantly, a mean-field magnetic potential are included in the model. The development is similar to previous models for liquid-crystalline polymers. The model predicts multiple orientational states for the dispersion, and this phase behavior is described in terms of an orientational order parameter S and an average alignment parameter J; the latter is introduced because the magnetic particles have distinguishable direction due to polarity. A transition from isotropic to nematic phases at equilibrium is predicted. Multiple nematic phases-both prolate and oblate-are predicted in the presence of steady shear flow and external magnetic field parallel to the flow. The effect of increasing magnetic interparticle interactions and particle concentration is also presented. Comparisons with experimental data for the steady shear viscosity show very good agreement. PMID:16256493

  12. Mesoscale Modelling of Westafrican Precipitation In Impetus Westafrica

    NASA Astrophysics Data System (ADS)

    Born, K.; Bachner, S.; Haase, G.; Hübener, H.; Paeth, H.; Sogalla, M.

    The objective of the IMPETUS Westafricaproject is the research on water availability, water use and management and future impacts of expected climate changes on the socio-economic development in two critical regions of Westafrica: On the northern side of the Sahara in the catchment of the Qued Drâa in Morocco, south of the Sahara and Sahel in the catchment of the river Ouémé in Benin. Precipitation is the most important input to the hydrological cycle in these regions. For any hydrologic or economic modeling we need spatially distributed precipitation fields as accurate as possible. Therefore, precipitation modeling is one scope for the meteorologists participating in IMPETUS. For detailed studies on the influence of land use changes on soil hydrology and plant growth, the spatial scale of used models should be as small as possible. Therefore, the use of mesoscale models for regional climate modelling is tested and further developped. Since causes of rainfall variability are multiscale phenomena--teleconnections with ENSO and NAO steer the rainfall variability as well as local changes like deforestation--a hierachy of models, from the global scale down to the Meso- /Micro- scale, was set up to study processes affecting rainfall variability in the regions of interest. This model chain is described in some detail, first results and fu- ture aims of research activities in the area of mesoscale modeling are shown.

  13. DEVELOPMENT OF A LAND-SURFACE MODEL PART I: APPLICATION IN A MESOSCALE METEOROLOGY MODEL

    EPA Science Inventory

    Parameterization of land-surface processes and consideration of surface inhomogeneities are very important to mesoscale meteorological modeling applications, especially those that provide information for air quality modeling. To provide crucial, reliable information on the diurn...

  14. An application of an efficient non-hydrostatic mesoscale model

    NASA Astrophysics Data System (ADS)

    Flassak, Th.; Moussiopoulos, N.

    1987-12-01

    This paper deals with a non-hydrostatic mesoscale model that achieves full vectorization on computers like the CYBER 205. The model formulation ensures the conservation of all fluxes and takes into account the terrain inhomogeneities by the aid of suitable transformations. The diagnostic equation for the pressure change is solved using a very efficient vectorized elliptic solver. By imposing appropriate boundary conditions no additional precautions at the boundaries are necessary to achieve meaningful results. As an application, the steady-state inviscid flow over a single mountain is simulated.

  15. Hydrodynamic modeling of Singapore's coastal waters: Nesting and model accuracy

    NASA Astrophysics Data System (ADS)

    Hasan, G. M. Jahid; van Maren, Dirk Sebastiaan; Ooi, Seng Keat

    2016-01-01

    The tidal variation in Singapore's coastal waters is influenced by large-scale, complex tidal dynamics (by interaction of the Indian Ocean and the South China Sea) as well as monsoon-driven low frequency variations, requiring a model with large spatial coverage. Close to the shores, the complex topography, influenced by headlands and small islands, requires a high resolution model to simulate tidal dynamics. This can be achieved through direct nesting or multi-scale nesting, involving multiple model grids. In this paper, we investigate the effect of grid resolution and multi-scale nesting on the tidal dynamics in Singapore's coastal waters, by comparing model results with observations using different statistical techniques. The results reveal that the intermediate-scale model is generally sufficiently accurate (equal to or better than the most refined model), but also that the most refined model is only more accurate when nested in the intermediate scale model (requiring multi-scale nesting). This latter is the result of the complex tidal dynamics around Singapore, where the dominantly diurnal tidal currents are decoupled from the semi-diurnal water level variations. Furthermore, different techniques to quantify model accuracy (harmonic analysis, basic statistics and more complex statistics) are inconsistent in determining which model is more accurate.

  16. Transitioning a unidirectional composite computer model from mesoscale to continuum

    NASA Astrophysics Data System (ADS)

    Chocron, Sidney; Zaera, Ramón; Walker, James; Brill, Alon; Kositski, Roman; Havazelet, Doron; Heisserer, Ulrich; van der Werff, Harm

    2015-09-01

    Ballistic impact on composites has been a challenging problem as seen in the abundant literature about the subject. Continuum models usually cannot properly predict deflection history on the back of the target while at the same time giving reasonable ballistic limits. According to the authors the main reason is that, while continuum models are very good at reproducing the elastic characteristics of the laminate, the models do not capture the behaviour of the "failed" material. A "failed" composite can still be very effective in stopping a projectile, because it can behave very similar to a dry woven fabric. The failure aspect is much easier to capture realistically with a mesoscale model. These models explicitly contain yarns and matrix allowing the matrix to fail while the yarns stay intact and continue to offer resistance to the projectile. This paper summarizes the work performed by the authors on the computationally expensive mesoscale models and, using them as benchmark computations, describes the first steps towards obtaining more computationally effective models that still keep the right physics of the impact.

  17. Mesoscale modeling of polyelectrolyte brushes with salt.

    PubMed

    Ibergay, Cyrille; Malfreyt, Patrice; Tildesley, Dominic J

    2010-06-01

    We report dissipative particle dynamics (DPD) simulations of a polyelectrolyte brush under athermal solvent conditions. The electrostatic interactions are calculated using the particle-particle particle-mesh (PPPM) method with charges distributed over the particles. The polymer beads, counterions, co-ions, and solvent particles are modeled explicitly. The DPD simulations show a dependence of the brush height on the grafting density and the charge fraction that is typical of the nonlinear osmotic brush regime. We report the effect of the addition of salt on the structural properties of the brush. In the case of a polyelectrolyte brush with a high surface coverage, the simulations reproduce the transition between the nonlinear osmotic brush regime where the thickness of the brush is independent of the salt concentration and the salted regime where the brush height decreases weakly with the salt concentration. PMID:20455593

  18. Evaluation of an Urban Canopy Parameterization in a Mesoscale Model

    SciTech Connect

    Chin, H S; Leach, M J; Sugiyama, G A; Leone, Jr., J M; Walker, H; Nasstrom, J; Brown, M J

    2004-03-18

    A modified urban canopy parameterization (UCP) is developed and evaluated in a three-dimensional mesoscale model to assess the urban impact on surface and lower atmospheric properties. This parameterization accounts for the effects of building drag, turbulent production, radiation balance, anthropogenic heating, and building rooftop heating/cooling. USGS land-use data are also utilized to derive urban infrastructure and urban surface properties needed for driving the UCP. An intensive observational period with clear-sky, strong ambient wind and drainage flow, and the absence of land-lake breeze over the Salt Lake Valley, occurring on 25-26 October 2000, is selected for this study. A series of sensitivity experiments are performed to gain understanding of the urban impact in the mesoscale model. Results indicate that within the selected urban environment, urban surface characteristics and anthropogenic heating play little role in the formation of the modeled nocturnal urban boundary layer. The rooftop effect appears to be the main contributor to this urban boundary layer. Sensitivity experiments also show that for this weak urban heat island case, the model horizontal grid resolution is important in simulating the elevated inversion layer. The root mean square errors of the predicted wind and temperature with respect to surface station measurements exhibit substantially larger discrepancies at the urban locations than the rural counterparts. However, the close agreement of modeled tracer concentration with observations fairly justifies the modeled urban impact on the wind direction shift and wind drag effects.

  19. Validation of an Urban Parameterization in a Mesoscale Model

    SciTech Connect

    Leach, M.J.; Chin, H.

    2001-07-19

    The Atmospheric Science Division at Lawrence Livermore National Laboratory uses the Naval Research Laboratory's Couple Ocean-Atmosphere Mesoscale Prediction System (COAMPS) for both operations and research. COAMPS is a non-hydrostatic model, designed as a multi-scale simulation system ranging from synoptic down to meso, storm and local terrain scales. As model resolution increases, the forcing due to small-scale complex terrain features including urban structures and surfaces, intensifies. An urban parameterization has been added to the Naval Research Laboratory's mesoscale model, COAMPS. The parameterization attempts to incorporate the effects of buildings and urban surfaces without explicitly resolving them, and includes modeling the mean flow to turbulence energy exchange, radiative transfer, the surface energy budget, and the addition of anthropogenic heat. The Chemical and Biological National Security Program's (CBNP) URBAN field experiment was designed to collect data to validate numerical models over a range of length and time scales. The experiment was conducted in Salt Lake City in October 2000. The scales ranged from circulation around single buildings to flow in the entire Salt Lake basin. Data from the field experiment includes tracer data as well as observations of mean and turbulence atmospheric parameters. Wind and turbulence predictions from COAMPS are used to drive a Lagrangian particle model, the Livermore Operational Dispersion Integrator (LODI). Simulations with COAMPS and LODI are used to test the sensitivity to the urban parameterization. Data from the field experiment, including the tracer data and the atmospheric parameters, are also used to validate the urban parameterization.

  20. Optogenetic stimulation of a meso-scale human cortical model

    NASA Astrophysics Data System (ADS)

    Selvaraj, Prashanth; Szeri, Andrew; Sleigh, Jamie; Kirsch, Heidi

    2015-03-01

    Neurological phenomena like sleep and seizures depend not only on the activity of individual neurons, but on the dynamics of neuron populations as well. Meso-scale models of cortical activity provide a means to study neural dynamics at the level of neuron populations. Additionally, they offer a safe and economical way to test the effects and efficacy of stimulation techniques on the dynamics of the cortex. Here, we use a physiologically relevant meso-scale model of the cortex to study the hypersynchronous activity of neuron populations during epileptic seizures. The model consists of a set of stochastic, highly non-linear partial differential equations. Next, we use optogenetic stimulation to control seizures in a hyperexcited cortex, and to induce seizures in a normally functioning cortex. The high spatial and temporal resolution this method offers makes a strong case for the use of optogenetics in treating meso scale cortical disorders such as epileptic seizures. We use bifurcation analysis to investigate the effect of optogenetic stimulation in the meso scale model, and its efficacy in suppressing the non-linear dynamics of seizures.

  1. Validation of a new Mesoscale Model for MARS .

    NASA Astrophysics Data System (ADS)

    De Sanctis, K.; Ferretti, R.; Forget, F.; Fiorenza, C.; Visconti, G.

    The study of Mars planet is very important because of the several similarities with the Earth. For the understanding of the dynamical processes which drive the martian atmosphere, a new Martian Mesoscale Model (MARS-MM5) is presented. The new model is based on the Pennsylvania State University (PSU)/National Centre for Atmosphere Research (NCAR) Mesoscale Model Version 5 \\citep{duh,gre}. MARS-MM5 has been adapted to Mars using soil characteristics and topography obtained by Mars Orbital Laser Altimeter (MOLA). Different cases, depending from data availability and corresponding to the equatorial region of Mars, have been selected for multiple MARS-MM5 simulations. To validate the different developments Mars Climate Database (MCD) and TES observations have been employed: MCD version 4.0 has been created on the basis of multi annual integration of Mars GCM output. The Thermal Emission Spectromter observations (TES) detected during Mars Global Surveyor (MGS) mission are used in terms of temperature. The new, and most important, aspect of this work is the direct validation of the newly generated MARS-MM5 in terms of three-dimensional observations. The comparison between MARS-MM5 and GCM horizontal and vertical temperature profiles shows a good agreement; moreover, a good agreement is also found between TES observations and MARS-MM5.

  2. Evaluation of cloud prediction and determination of critical relative humidity for a mesoscale numerical weather prediction model

    SciTech Connect

    Seaman, N.L.; Guo, Z.; Ackerman, T.P.

    1996-04-01

    Predictions of cloud occurrence and vertical location from the Pennsylvannia State University/National Center for Atmospheric Research nonhydrostatic mesoscale model (MM5) were evaluated statistically using cloud observations obtained at Coffeyville, Kansas, as part of the Second International satellite Cloud Climatology Project Regional Experiment campaign. Seventeen cases were selected for simulation during a November-December 1991 field study. MM5 was used to produce two sets of 36-km simulations, one with and one without four-dimensional data assimilation (FDDA), and a set of 12-km simulations without FDDA, but nested within the 36-km FDDA runs.

  3. A hierarchical nest survival model integrating incomplete temporally varying covariates.

    PubMed

    Converse, Sarah J; Royle, J Andrew; Adler, Peter H; Urbanek, Richard P; Barzen, Jeb A

    2013-11-01

    Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

  4. A hierarchical nest survival model integrating incomplete temporally varying covariates

    PubMed Central

    Converse, Sarah J; Royle, J Andrew; Adler, Peter H; Urbanek, Richard P; Barzen, Jeb A

    2013-01-01

    Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

  5. A hierarchical nest survival model integrating incomplete temporally varying covariates

    USGS Publications Warehouse

    Converse, Sarah J.; Royle, J. Andrew; Adler, Peter H.; Urbanek, Richard P.; Barzan, Jeb A.

    2013-01-01

    Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood-feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the

  6. Use of observational and model-derived fields and regime model output statistics in mesoscale forecasting

    NASA Technical Reports Server (NTRS)

    Forbes, G. S.; Pielke, R. A.

    1985-01-01

    Various empirical and statistical weather-forecasting studies which utilize stratification by weather regime are described. Objective classification was used to determine weather regime in some studies. In other cases the weather pattern was determined on the basis of a parameter representing the physical and dynamical processes relevant to the anticipated mesoscale phenomena, such as low level moisture convergence and convective precipitation, or the Froude number and the occurrence of cold-air damming. For mesoscale phenomena already in existence, new forecasting techniques were developed. The use of cloud models in operational forecasting is discussed. Models to calculate the spatial scales of forcings and resultant response for mesoscale systems are presented. The use of these models to represent the climatologically most prevalent systems, and to perform case-by-case simulations is reviewed. Operational implementation of mesoscale data into weather forecasts, using both actual simulation output and method-output statistics is discussed.

  7. Mesoscale Modeling of Impact Compaction of Primitive Solar System Solids

    NASA Astrophysics Data System (ADS)

    Davison, Thomas M.; Collins, Gareth S.; Bland, Philip A.

    2016-04-01

    We have developed a method for simulating the mesoscale compaction of early solar system solids in low-velocity impact events using the iSALE shock physics code. Chondrules are represented by non-porous disks, placed within a porous matrix. By simulating impacts into bimodal mixtures over a wide range of parameter space (including the chondrule-to-matrix ratio, the matrix porosity and composition, and the impact velocity), we have shown how each of these parameters influences the shock processing of heterogeneous materials. The temperature after shock processing shows a strong dichotomy: matrix temperatures are elevated much higher than the chondrules, which remain largely cold. Chondrules can protect some matrix from shock compaction, with shadow regions in the lee side of chondrules exhibiting higher porosity that elsewhere in the matrix. Using the results from this mesoscale modeling, we show how the ɛ - α porous-compaction model parameters depend on initial bulk porosity. We also show that the timescale for the temperature dichotomy to equilibrate is highly dependent on the porosity of the matrix after the shock, and will be on the order of seconds for matrix porosities of less than 0.1, and on the order of tens to hundreds of seconds for matrix porosities of ˜0.3-0.5. Finally, we have shown that the composition of the post-shock material is able to match the bulk porosity and chondrule-to-matrix ratios of meteorite groups such as carbonaceous chondrites and unequilibrated ordinary chondrites.

  8. Anisotropic mesoscale eddy transport in ocean general circulation models

    NASA Astrophysics Data System (ADS)

    Reckinger, Scott; Fox-Kemper, Baylor; Bachman, Scott; Bryan, Frank; Dennis, John; Danabasoglu, Gokhan

    2014-11-01

    In modern climate models, the effects of oceanic mesoscale eddies are introduced by relating subgrid eddy fluxes to the resolved gradients of buoyancy or other tracers, where the proportionality is, in general, governed by an eddy transport tensor. The symmetric part of the tensor, which represents the diffusive effects of mesoscale eddies, is universally treated isotropically. However, the diffusive processes that the parameterization approximates, such as shear dispersion and potential vorticity barriers, typically have strongly anisotropic characteristics. Generalizing the eddy diffusivity tensor for anisotropy extends the number of parameters from one to three: major diffusivity, minor diffusivity, and alignment. The Community Earth System Model (CESM) with the anisotropic eddy parameterization is used to test various choices for the parameters, which are motivated by observations and the eddy transport tensor diagnosed from high resolution simulations. Simply setting the ratio of major to minor diffusivities to a value of five globally, while aligning the major axis along the flow direction, improves biogeochemical tracer ventilation and reduces temperature and salinity biases. These effects can be improved by parameterizing the oceanic anisotropic transport mechanisms.

  9. Modeling Mesoscale Eddies in the North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Chao, Yi

    1999-01-01

    Ocean modeling plays an important role in understanding the current climatic conditions and predicting the future climate change. Modeling the ocean at eddy-permitting and/or eddy resolving resolutions (1/3 degree or higher) has a two-fold objective. One part is to represent the ocean as realistically as possible, because mesoscale eddies have an impact on the large-scale circulation. The second objective is to learn how to represent effects of mesoscale eddies without explicitly resolving them. This is particularly important for climate models which cannot be run at eddy-resolving resolutions because of the computational constraints. At JPL, a 1/6 degree latitude by 1/6 degree longitude with 37 vertical levels Atlantic Ocean model has been developed. The model is based on the Parallel Ocean Program (POP) developed at Los Alamos National Laboratory (LANL). Using the 256-processor Cray T3D, we have conducted a 40-year integration of this Atlantic eddy-resolving ocean model. A regional analysis demonstrate that many observed features associated with the Caribbean Sea eddies can be realistically simulated by this model. Analysis of this Atlantic eddy-resolving ocean model further suggests that these Caribbean Sea eddies are connected with eddies formed outside the Caribbean Sea at the confluence of the North Brazil Current (NBC) and the North Equatorial Countercurrent. The diagram of the model simulated surface current shows that the Caribbean eddies ultimately originate in the NBC retroflection region, traveling more than a year from the North Brazil coast through the Lesser Antilles into the Caribbean Sea and eventually into the Gulf of Mexico. Additional information is contained in the original.

  10. High-frequency Environmental Tracer Data to Improve our Knowledge of Hydrological Functioning in Nested Mesoscale Catchments

    NASA Astrophysics Data System (ADS)

    Tetzlaff, D.; Waldron, S.; Brewer, M. J.; Soulsby, C.

    2006-12-01

    High resolution (15 minute) continuous environmental tracer data (conductivity, pH and derived Gran alkalinity,) were used to investigate the hydrological functioning of the 233km2 Feugh catchment in NE Scotland and two of its nested sub-catchments (42km2 and 1km2). The continuous data indicated detailed and subtle changes in stream chemistry. Diurnal variation in alkalinity and flow were observed under low flow conditions, attributed to instream respiration and riparian evapotranspiration respectively. At high flows, abrupt threshold behaviour was evident during storm events as hydrological sources in the acidic surface horizons of the catchment soils replace groundwater as the dominant source of runoff. Using Gran alkalinity to define end-member compositions, chemically-based hydrograph separations revealed that as catchment scale increased, groundwater contributions to annual runoff increased from 53 ± 11 %, to 66 ± 6 % , to 70 ± 11%. Mean residence times were estimated from weekly δ 18O data. Uncertainty increased from 1.3-4.7 months to 2.4-10.6 months to 2.5-11.1 months. The use of continuous tracer data increased the sophistication of our conceptual model of catchment processes: increasing dominance of responsive peaty soils leads to more saturation overland flow, increased flashiness of runoff, reduced groundwater recharge, reduced MRTs and more marked diurnal variations in flow, which drive concomitant difference in hydrochemistry.

  11. Three-dimensional parabolic equation modeling of mesoscale eddy deflection.

    PubMed

    Heaney, Kevin D; Campbell, Richard L

    2016-02-01

    The impact of mesoscale oceanography, including ocean fronts and eddies, on global scale low-frequency acoustics is examined using a fully three-dimensional parabolic equation model. The narrowband acoustic signal, for frequencies from 2 to 16 Hz, is simulated from a seismic event on the Kerguellen Plateau in the South Indian Ocean to an array of receivers south of Ascension Island in the South Atlantic, a distance of 9100 km. The path was chosen for its relevance to seismic detections from the HA10 Ascension Island station of the International Monitoring System, for its lack of bathymetric interaction, and for the dynamic oceanography encountered as the sound passes the Cape of Good Hope. The acoustic field was propagated through two years (1992 and 1993) of the eddy-permitting ocean state estimation ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) system. The range of deflection of the back-azimuth was 1.8° with a root-mean-square of 0.34°. The refraction due to mesoscale oceanography could therefore have significant impacts upon localization of distant low-frequency sources, such as seismic or nuclear test events. PMID:26936572

  12. Mesoscale constitutive modeling of non-crystallizing filled elastomers

    NASA Astrophysics Data System (ADS)

    Harish, Ajay B.; Wriggers, Peter; Jungk, Juliane; Hojdis, Nils; Recker, Carla

    2016-04-01

    Elastomers are exceptional materials owing to their ability to undergo large deformations before failure. However, due to their very low stiffness, they are not always suitable for industrial applications. Addition of filler particles provides reinforcing effects and thus enhances the material properties that render them more versatile for applications like tyres etc. However, deformation behavior of filled polymers is accompanied by several nonlinear effects like Mullins and Payne effect. To this day, the physical and chemical changes resulting in such nonlinear effect remain an active area of research. In this work, we develop a heterogeneous (or multiphase) constitutive model at the mesoscale explicitly considering filler particle aggregates, elastomeric matrix and their mechanical interaction through an approximate interface layer. The developed constitutive model is used to demonstrate cluster breakage, also, as one of the possible sources for Mullins effect observed in non-crystallizing filled elastomers.

  13. Mesoscale Eddy Parameterization in an Idealized Primitive Equations Model

    NASA Astrophysics Data System (ADS)

    Anstey, J.; Zanna, L.

    2014-12-01

    Large-scale ocean currents such as the Gulf Stream and Kuroshio Extension are strongly influenced by mesoscale eddies, which have spatial scales of order 10-100 km. The effects of these eddies are poorly represented in many state-of-the-art ocean general circulation models (GCMs) due to the inadequate spatial resolution of these models. In this study we examine the response of the large-scale ocean circulation to the rectified effects of eddy forcing - i.e., the role played by surface-intensified mesoscale eddies in sustaining and modulating an eastward jet that separates from an intense western boundary current (WBC). For this purpose a primitive equations ocean model (the MITgcm) in an idealized wind-forced double-gyre configuration is integrated at eddy-resolving resolution to reach a forced-dissipative equilibrium state that captures the essential dynamics of WBC-extension jets. The rectified eddy forcing is diagnosed as a stochastic function of the large-scale state, this being characterized by the manner in which potential vorticity (PV) contours become deformed. Specifically, a stochastic function based on the Laplacian of the material rate of change of PV is examined in order to compare the primitive equations results with those of a quasi-geostrophic model in which this function has shown some utility as a parameterization of eddy effects (Porta Mana and Zanna, 2014). The key question is whether an eddy parameterization based on quasi-geostrophic scaling is able to carry over to a system in which this scaling is not imposed (i.e. the primitive equations), in which unbalanced motions occur.

  14. Initialization of a mesoscale model for April 10, 1979, using alternative data sources

    NASA Technical Reports Server (NTRS)

    Kalb, M. W.

    1984-01-01

    A 35 km grid limited area mesoscale model was initialized with high density SESAME radiosonde data and high density TIROS-N satellite temperature profiles for April 10, 1979. These data sources were used individually and with low level wind fields constructed from surface wind observations. The primary objective was to examine the use of satellite temperature data for initializing a mesoscale model by comparing the forecast results with similar experiments employing radiosonde data. The impact of observed low level winds on the model forecasts was also investigated with experiments varying the method of insertion. All forecasts were compared with each other and with mesoscale observations for precipitation, mass and wind structure. Several forecasts produced convective precipitation systems with characteristics satisfying criteria for a mesoscale convective complex. High density satellite temperature data and balanced winds can be used in a mesoscale model to produce forecasts which verify favorably with observations.

  15. A spatial model of waterfowl nest site selection in grassland nesting cover

    NASA Astrophysics Data System (ADS)

    Pool, Duane Bruce

    Ducks Unlimited's (DU) mission statement is focused on providing for the annual lifecycle needs of migratory waterfowl. The largest impacts to the success and numbers of continental populations are determined by their activities on the breeding grounds. To model and therefore manage habitats and landscapes for ducks (Anas and Aythya spp.) it is necessary to understand several characteristics of their behavior. This research builds a model of nest site selection from nest probability based on remotely sensed data, presence data and minimum threshold theory. The methods used are applicable to other sensor platforms as well as other target species or phenomenon. Using data compression techniques, logistic regression, and spatial statistical functions (Ripley's k-function, a global k-function, and Multiple Response Permutation Procedure) we tested the observed point patterns and developed a point process model to predict nesting patterns. The application of this type of fine resolution database, validated by empirical data, will be more powerful than either classified remote sensing data or field level nest demographic data alone. In the largest of the five study sites, which was also the site with the greatest number of observations, the pattern of nests were significantly different from Poisson. The model developed to fit these data was tested using the other sites and the observed data on the other four sites were not shown to be significantly different from the model. The tests for spatial association showed some evidence negative association between Blue-winged Teal and Gadwall as well as between successful and unsuccessful nest. There is some evidence that a process of natural selection may exist and the future studies should be designed with this in mind. These data will be used as a baseline for future habitat manipulation and controlled experiments on the DU Goebel Ranch complex. The results of this and future studies will be used as the basis for DU strategic

  16. The Challenge of Forecasting the Onset and Development of Radiation Fog Using Mesoscale Atmospheric Models

    NASA Astrophysics Data System (ADS)

    Steeneveld, G. J.; Ronda, R. J.; Holtslag, A. A. M.

    2015-02-01

    The numerical weather prediction of radiation fog is challenging, as many models typically show large biases for the timing of the onset and dispersal of the fog, as well as for its depth and liquid water content. To understand the role of physical processes, i.e. turbulence, radiation, land-surface coupling, and microphysics, we evaluate the HARMONIE and Weather Research and Forecasting (WRF) mesoscale models for two contrasting warm fog episodes at the relatively flat terrain around the Cabauw tower facility in the Netherlands. One case involves a radiation fog that arose in calm anticyclonic conditions, and the second is a radiation fog that developed just after a cold front passage. The WRF model represents the radiation fog well, while the HARMONIE model forecasts a stratus lowering fog layer in the first case and hardly any fog in the second case. Permutations of parametrization schemes for boundary-layer mixing, radiation and microphysics, each for two levels of complexity, have been evaluated within the WRF model. It appears that the boundary-layer formulation is critical for forecasting the fog onset, while for fog dispersal the choice of the microphysical scheme is a key element, where a double-moment scheme outperforms any of the single-moment schemes. Finally, the WRF model results appear to be relatively insensitive to horizontal grid spacing, but nesting deteriorates the modelled fog formation. Increasing the domain size leads to a more scattered character of the simulated fog. Model results with one-way or two-way nesting show approximately comparable results.

  17. Observation Denial and Performance of a Local Mesoscale Model

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III

    2009-01-01

    .Forecasters at the 45th Weather Squadron (45 WS) use observations from the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) wind tower network and the CCAFS (XMR) daily rawinsonde observations (RAOB) to issue and verify wind advisories and warnings for operations. These observations are also used by the National Weather Service (NWS) Spaceflight Meteorology Group (SMG) in Houston, Texas and the NWS Melbourne, Florida (NWS MLB) to initialize their locally-run mesoscale models. In addition, SMG uses these observations to support shuttle landings at the Shuttle Landing Facility (SLF). Due to impending budget cuts, some or all of the wind towers on the east-central Florida mainland and the XMR RAOBs may be eliminated. The locations of the mainland towers and XMR RAOB site are shown in Figure 1. The loss of these data may impact the forecast capability of the 45 WS, SMG and NWS MLB.

  18. Mesoscale Simulation Data for Initializing Fast-Time Wake Transport and Decay Models

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.; Vanvalkenburg, Randal L.; Pruis, Mathew J.; LimonDuparcmeur, Fanny M.

    2012-01-01

    The fast-time wake transport and decay models require vertical profiles of crosswinds, potential temperature and the eddy dissipation rate as initial conditions. These inputs are normally obtained from various field sensors. In case of data-denied scenarios or operational use, these initial conditions can be provided by mesoscale model simulations. In this study, the vertical profiles of potential temperature from a mesoscale model were used as initial conditions for the fast-time wake models. The mesoscale model simulations were compared against available observations and the wake model predictions were compared with the Lidar measurements from three wake vortex field experiments.

  19. Numerical Simulation of Chennai Heavy Rainfall Using MM5 Mesoscale Model with Different Cumulus Parameterization Schemes

    NASA Astrophysics Data System (ADS)

    Litta, A. J.; Chakrapani, B.; Mohankumar, K.

    2007-07-01

    Heavy rainfall events become significant in human affairs when they are combined with hydrological elements. The problem of forecasting heavy precipitation is especially difficult since it involves making a quantitative precipitation forecast, a problem well recognized as challenging. Chennai (13.04°N and 80.17°E) faced incessant and heavy rain about 27 cm in 24 hours up to 8.30 a.m on 27th October 2005 completely threw life out of gear. This torrential rain caused by deep depression which lay 150km east of Chennai city in Bay of Bengal intensified and moved west north-west direction and crossed north Tamil Nadu and south Andhra Pradesh coast on 28th morning. In the present study, we investigate the predictability of the MM5 mesoscale model using different cumulus parameterization schemes for the heavy rainfall event over Chennai. MM5 Version 3.7 (PSU/NCAR) is run with two-way triply nested grids using Lambert Conformal Coordinates (LCC) with a nest ratio of 3:1 and 23 vertical layers. Grid sizes of 45, 15 and 5 km are used for domains 1, 2 and 3 respectively. The cumulus parameterization schemes used in this study are Anthes-Kuo scheme (AK), the Betts-Miller scheme (BM), the Grell scheme (GR) and the Kain-Fritsch scheme (KF). The present study shows that the prediction of heavy rainfall is sensitive to cumulus parameterization schemes. In the time series of rainfall, Grell scheme is in good agreement with observation. The ideal combination of the nesting domains, horizontal resolution and cloud parameterization is able to simulate the heavy rainfall event both qualitatively and quantitatively.

  20. Mesoscale Modeling of Impact Compaction of Primitive Solar System Solids

    NASA Astrophysics Data System (ADS)

    Davison, Thomas M.; Collins, Gareth S.; Bland, Philip A.

    2016-04-01

    We have developed a method for simulating the mesoscale compaction of early solar system solids in low-velocity impact events using the iSALE shock physics code. Chondrules are represented by non-porous disks, placed within a porous matrix. By simulating impacts into bimodal mixtures over a wide range of parameter space (including the chondrule-to-matrix ratio, the matrix porosity and composition, and the impact velocity), we have shown how each of these parameters influences the shock processing of heterogeneous materials. The temperature after shock processing shows a strong dichotomy: matrix temperatures are elevated much higher than the chondrules, which remain largely cold. Chondrules can protect some matrix from shock compaction, with shadow regions in the lee side of chondrules exhibiting higher porosity that elsewhere in the matrix. Using the results from this mesoscale modeling, we show how the ε ‑ α porous-compaction model parameters depend on initial bulk porosity. We also show that the timescale for the temperature dichotomy to equilibrate is highly dependent on the porosity of the matrix after the shock, and will be on the order of seconds for matrix porosities of less than 0.1, and on the order of tens to hundreds of seconds for matrix porosities of ∼0.3–0.5. Finally, we have shown that the composition of the post-shock material is able to match the bulk porosity and chondrule-to-matrix ratios of meteorite groups such as carbonaceous chondrites and unequilibrated ordinary chondrites.

  1. Meteorological predictions for Mars 2020 Exploration Rover high-priority landing sites throug MRAMS Mesoscale Modeling

    NASA Astrophysics Data System (ADS)

    Pla-García, Jorge; Rafkin, Scot C. R.

    2015-04-01

    The Mars Regional Atmospheric Modeling System (MRAMS) is used to predict meteorological conditions that are likely to be encountered by the Mars 2020 Exploration Rover at several proposed landing sites during entry, descent, and landing (EDL). The meteorology during the EDL window at most of the sites is dynamic. The intense heating of the lower atmosphere drives intense thermals and mesoscale thermal circulations. Moderate mean winds, wind shear, turbulence, and vertical air currents associated with convection are present and potentially hazardous to EDL [1]. Nine areas with specific high-priority landing ellipses of the 2020 Rover, are investigated: NE Syrtis, Nili Fossae, Nili Fossae Carbonates, Jezero Crater Delta, Holden Crater, McLaughlin Crater, Southwest Melas Basin, Mawrth Vallis and East Margaritifer Chloride. MRAMS was applied to the landing site regions using nested grids with a spacing of 330 meters on the innermost grid that is centered over each landing site. MRAMS is ideally suited for this investigation; the model is explicitly designed to simulate Mars' atmospheric thermal circulations at the mesoscale and smaller with realistic, high-resolution surface properties [2, 3]. Horizontal wind speeds, both vertical profiles and vertical cross-sections wind speeds, are studied. For some landing sites simulations, two example configurations -including and not including Hellas basin in the mother domain- were generated, in order to study how the basin affects the innermost grids circulations. Afternoon circulations at all sites pose some risk entry, descent, and landing. Most of the atmospheric hazards are not evident in current observational data and general circulation model simulations and can only be ascertained through mesoscale modeling of the region. Decide where to go first and then design a system that can tolerate the environment would greatly minimize risk. References: [1] Rafkin, S. C. R., and T. I. Michaels (2003), J. Geophys. Res., 108(E12

  2. Systematic multiscale models for deep convection on mesoscales

    NASA Astrophysics Data System (ADS)

    Klein, Rupert; Majda, Andrew J.

    2006-11-01

    This paper builds on recent developments of a unified asymptotic approach to meteorological modeling [ZAMM, 80: 765 777, 2000, SIAM Proc. App. Math. 116, 227 289, 2004], which was used successfully in the development of Systematic multiscale models for the tropics in Majda and Klein [J. Atmosph. Sci. 60: 393 408, 2003] and Majda and Biello [PNAS, 101: 4736 4741, 2004]. Biello and Majda [J. Atmosph. Sci. 62: 1694 1720, 2005]. Here we account for typical bulk microphysics parameterizations of moist processes within this framework. The key steps are careful nondimensionalization of the bulk microphysics equations and the choice of appropriate distinguished limits for the various nondimensional small parameters that appear. We are then in a position to study scale interactions in the atmosphere involving moist physics. We demonstrate this by developing two systematic multiscale models that are motivated by our interest in mesoscale organized convection. The emphasis here is on multiple length scales but common time scales. The first of these models describes the short-time evolution of slender, deep convective hot towers with horizontal scale ~ 1 km interacting with the linearized momentum balance on length and time scales of (10 km/3 min). We expect this model to describe how convective inhibition may be overcome near the surface, how the onset of deep convection triggers convective-scale gravity waves, and that it will also yield new insight into how such local convective events may conspire to create larger-scale strong storms. The second model addresses the next larger range of length and time scales (10 km, 100 km, and 20 min) and exhibits mathematical features that are strongly reminiscent of mesoscale organized convection. In both cases, the asymptotic analysis reveals how the stiffness of condensation/evaporation processes induces highly nonlinear dynamics. Besides providing new theoretical insights, the derived models may also serve as a theoretical devices

  3. Numerical photochemical modeling over Madrid (Spain) mesoscale urban area

    NASA Astrophysics Data System (ADS)

    San Jose, Roberto; Ramirez-Montesinos, Arturo; Marcelo, Luis M.; Sanz, Miguel A.; Rodriguez, Luis M.

    1995-09-01

    Photochemical air quality models provide the most defensible method for relating future air quality to changes in emission, and hence are the foundation for determining the effectiveness of proposed control strategies. In this contribution, we will show results from different photochemical schemes under typical emission conditions for a summer day in the Madrid mesocsale urban area. We will show that complex numerical integrated urban mesoscale models are a powerful tool to predict the ozone levels on this area. The comparison of model simulations at different grid points show an acceptable preliminary behavior. The results presented in this paper are prepared for August 15th, 1991 and the predicted ozone values are compared with those measured at two stations of the Madrid city monitoring network. Results show that the shape is successfully predicted by using the NUFOMO (numerical photochemical model) model. Because of the computer limitations, we have limited the results to this case study. Further investigations will provide additional information to produce a statistical analysis of the results. However, preliminary results show that the NUFOMO model is able to reproduce the measured ozone values.

  4. Operational Assimilation of GOES Data into a Mesoscale Model

    NASA Technical Reports Server (NTRS)

    Lapenta, William; Suggs, Ron; McNider, Richard; Jedlovec, Gary; Dembek, Scott

    2000-01-01

    A technique has been developed for assimilating GOES-derived skin temperature tendencies and insolation into the surface energy budget equation of a mesoscale model so that the simulated rate of temperature change closely agrees with the satellite observations. A critical assumption of the technique is that the availability of moisture (either from the soil or vegetation) is the least known term in the model's surface energy budget. Therefore, the simulated latent heat flux, which is a function of surface moisture availability, is adjusted based upon differences between the modeled and satellite- observed skin temperature tendencies. An advantage of this technique is that satellite temperature tendencies are assimilated in an energetically consistent manner that avoids energy imbalances and surface stability problems that arise from direct assimilation of surface shelter temperatures. The fact that the rate of change of the satellite skin temperature is used rather than the absolute temperature means that sensor calibration is not as critical. The technique has been employed on a semi-operational basis at the Global Hydrology and Climate Center (GHCC) within the Penn State/National Center for Atmospheric Research (PSU/NCAR) Mesoscale Model (MM5) since 1 November 1998. We performed the assimilation on a model grid centered over the Southeastern US. In addition, a control run without assimilation was performed to provide insight into the performance of the assimilation technique. Bulk verification statistics (BIAS and RMSE) of surface air temperature and relative humidity of more than 250 case days has been performed to date. Results show that assimilation of the satellite data results reduces both the bias and RMSE for simulations of surface air temperature and relative humidity. We are working with forecasters at the National Weather Service Forecast Office located in Birmingham, AL to evaluate the impact of the assimilation on precipitation forecasts. In addition

  5. Performance of a Local Mesoscale Model with Data Denial

    NASA Technical Reports Server (NTRS)

    Watson, Leela; Baumann, William H., III

    2008-01-01

    Forecasters at the 45th Weather Squadron (45 WS) use observations from the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) wind tower network and daily rawinsonde observations (RAOB) to issue and verify wind advisories, watches, and warnings for operations. They are also used by the Spaceflight Meteorology Group and Melbourne, Florida National Weather Service to initialize locally run mesoscale models. Due to impending budget cuts, some or all of the mainland wind towers and RAOBs may be eliminated, The loss of these data may significantly impact the forecast capability of the 45 WS and SMG. The Applied Meteorology Unit (AMU) was tasked to conduct an objective independent modeling study to determine how important these observations are to the accuracy of the model output used by the forecasters as input to their forecasts. To accomplish this, the AMU performed a sensitivity study using the Weather Research and Forecasting (WRF) model run with and without KSC/CCAFS wind tower and CCAFS RAOB observations and assessed the accuracy of model forecasts by comparing them to the observations.

  6. LMD - SwRI Martian Mesoscale Models Intercomparison for ExoMars Landing Site Characterization

    NASA Astrophysics Data System (ADS)

    Bertrand, T.; Spiga, A.; Rafkin, S.; Colaitis, A.; Forget, F.; Millour, E.

    2013-09-01

    Martian mesoscale models realisticaly simulate Martian meteorology at finer scales (~10km) than Global Climate Models (GCM). This modelling is becoming a central source of insights and diagnostics for future exploration of Mars and is useful to provide best-guesses of atmospheric variations of temperature and wind at mesoscale level. In such context, Model intercomparisons are a fruitful way to evaluate and assess the obtained predictions.

  7. Estimators for variance components in structured stair nesting models

    NASA Astrophysics Data System (ADS)

    Monteiro, Sandra; Fonseca, Miguel; Carvalho, Francisco

    2016-06-01

    The purpose of this paper is to present the estimation of the components of variance in structured stair nesting models. The relationship between the canonical variance components and the original ones, will be very important in obtaining that estimators.

  8. Analysis of Surface Heterogeneity Effects with Mesoscale Terrestrial Modeling Platforms

    NASA Astrophysics Data System (ADS)

    Simmer, C.

    2015-12-01

    An improved understanding of the full variability in the weather and climate system is crucial for reducing the uncertainty in weather forecasting and climate prediction, and to aid policy makers to develop adaptation and mitigation strategies. A yet unknown part of uncertainty in the predictions from the numerical models is caused by the negligence of non-resolved land surface heterogeneity and the sub-surface dynamics and their potential impact on the state of the atmosphere. At the same time, mesoscale numerical models using finer horizontal grid resolution [O(1)km] can suffer from inconsistencies and neglected scale-dependencies in ABL parameterizations and non-resolved effects of integrated surface-subsurface lateral flow at this scale. Our present knowledge suggests large-eddy-simulation (LES) as an eventual solution to overcome the inadequacy of the physical parameterizations in the atmosphere in this transition scale, yet we are constrained by the computational resources, memory management, big-data, when using LES for regional domains. For the present, there is a need for scale-aware parameterizations not only in the atmosphere but also in the land surface and subsurface model components. In this study, we use the recently developed Terrestrial Systems Modeling Platform (TerrSysMP) as a numerical tool to analyze the uncertainty in the simulation of surface exchange fluxes and boundary layer circulations at grid resolutions of the order of 1km, and explore the sensitivity of the atmospheric boundary layer evolution and convective rainfall processes on land surface heterogeneity.

  9. A Mesoscale Model of DNA and Its Renaturation

    PubMed Central

    Sambriski, E.J.; Schwartz, D.C.; de Pablo, J.J.

    2009-01-01

    A mesoscale model of DNA is presented (3SPN.1), extending the scheme previously developed by our group. Each nucleotide is mapped onto three interaction sites. Solvent is accounted for implicitly through a medium-effective dielectric constant and electrostatic interactions are treated at the level of Debye-Hückel theory. The force field includes a weak, solvent-induced attraction, which helps mediate the renaturation of DNA. Model parameterization is accomplished through replica exchange molecular dynamics simulations of short oligonucleotide sequences over a range of composition and chain length. The model describes the melting temperature of DNA as a function of composition as well as ionic strength, and is consistent with heat capacity profiles from experiments. The dependence of persistence length on ionic strength is also captured by the force field. The proposed model is used to examine the renaturation of DNA. It is found that a typical renaturation event occurs through a nucleation step, whereby an interplay between repulsive electrostatic interactions and colloidal-like attractions allows the system to undergo a series of rearrangements before complete molecular reassociation occurs. PMID:19254530

  10. Simulation of elevated long-range plume transport using a mesoscale meteorological model

    NASA Astrophysics Data System (ADS)

    Boybeyi, Zafer; Raman, Sethu

    A three-dimensional mesoscale meteorological model was used to construct a modeling system in order to investigate atmospheric dispersion in mesoscale flow fields. The mesoscale model was first coupled to a three-dimensional Monte Carlo (Lagrangian particle) dispersion model, and then an Eulerian dispersion model was embedded into the mesoscale model. Both the Eulerian model and the Monte Carlo model are based on the wind and turbulence fields simulated by the mesoscale model. The modeling system was then applied to the Tennessee Plume Study field experiments on 23 August 1978. The field experiments were basically designed to provide information on the dynamics of plume transport over long distances, and primarily targeted the plume from the Cumberland steam plant. Wind and turbulence fields were first simulated by the mesoscale model. The transport and diffusion of pollutants from the Cumberland steam plant were then simulated by the dispersion models, using these wind and turbulence fields. The results demonstrated that the modeling system generally performed satisfactorily, reproducing the trajectory and spread of the Cumberland plume.

  11. Fog simulation using a mesoscale model in and around the Yodo River Basin, Japan.

    PubMed

    Hikari, Shimadera; Kundan, Lal Shrestha; Akira, Kondo; Akikazu, Kaga; Yoshio, Inoue

    2008-01-01

    In this study, fog simulations were conducted using the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) in and around the Yodo River Basin, Japan. The purpose is to investigate the MM5 performance of fog simulation for long-term periods. The simulations were performed for January, February, March, and July, 2005 with a coarse 3-km and a nested fine 1-km grid domains. Results of the simulations were compared with data from ten meteorological observatories, fog sampling site in Mt. Rokko, and visibility measurement sites along the Second Meishin Expressway. At the meteorological observatories, the MM5 predictions agreed well with the observed temperature and specific humidity. In the Mt. Rokko region, MM5 generally reproduced the occurrence of relatively thick fog events but tended to overestimate liquid water content (LWC) of fog (by factors of 2.2-3.3 in terms of monthly mean LWC). In the Second Meishin Expressway region, while MM5 identified the specific sites at which fog either frequently or seldom occurs, the model underestimated the monthly fog frequencies by factors of more than 1.5. Overall, MM5 reproduced the general trend of fog events, and the model performance may be improved by using more adequate land surface data and suitable physics options for our study. PMID:18814580

  12. A survey of nested grid techniques and their potential for use within the MASS weather prediction model

    NASA Technical Reports Server (NTRS)

    Koch, Steven E.; Mcqueen, Jeffery T.

    1987-01-01

    A survey of various one- and two-way interactive nested grid techniques used in hydrostatic numerical weather prediction models is presented and the advantages and disadvantages of each method are discussed. The techniques for specifying the lateral boundary conditions for each nested grid scheme are described in detail. Averaging and interpolation techniques used when applying the coarse mesh grid (CMG) and fine mesh grid (FMG) interface conditions during two-way nesting are discussed separately. The survey shows that errors are commonly generated at the boundary between the CMG and FMG due to boundary formulation or specification discrepancies. Methods used to control this noise include application of smoothers, enhanced diffusion, or damping-type time integration schemes to model variables. The results from this survey provide the information needed to decide which one-way and two-way nested grid schemes merit future testing with the Mesoscale Atmospheric Simulation System (MASS) model. An analytically specified baroclinic wave will be used to conduct systematic tests of the chosen schemes since this will allow for objective determination of the interfacial noise in the kind of meteorological setting for which MASS is designed. Sample diagnostic plots from initial tests using the analytic wave are presented to illustrate how the model-generated noise is ascertained. These plots will be used to compare the accuracy of the various nesting schemes when incorporated into the MASS model.

  13. High resolution topography and land cover databases for wind resource assessment using mesoscale models

    NASA Astrophysics Data System (ADS)

    Barranger, Nicolas; Stathopoulos, Christos; Kallos, Georges

    2013-04-01

    . Following, the implementation of all databases, a high resolution simulation is performed over the complex terrain area of Northern Spain. The results are compared with meteorological station in the Navarra region and tall masts available on site. Using two way nesting techniques, the model is simultaneously resolving the synoptic forcing over Spanish Peninsula, mesoscale features over Navarra Region and microscale flow pattern passing around the Alaiz Mountain. To do so, multiple grids nests are set up in which the resolution varies gradually from the order of 10km to 100m. The time step decreases from twenty seconds to tens of milliseconds according to the Courant Friedrichs Lewy condition. The model that features Message Passing Interface is run using 64 cores. For high resolution grids (less than 500m), local convection is resolved using Large eddy simulation (LES) turbulent closure schemes. The LES technique provides a more detailed characterization of microscale turbulent flows using the complete Reynolds stress tensor for the sub filter scale parameterization.

  14. Release of potential instability by mesoscale triggering - An objective model simulation. [in precipitation numerical weather forecasting

    NASA Technical Reports Server (NTRS)

    Matthews, D. A.

    1978-01-01

    The effects of mesoscale triggering on organized nonsevere convective cloud systems in the High Plains are considered. Two experiments were conducted to determine if a one-dimensional quasi-time dependent model could (1) detect soundings which were sensitive to mesoscale triggering, and (2) discriminate between cases which had mesoscale organized convection and those with no organized convection. The MESOCU model was used to analyze the available potential instability and thermodynamic potential for cloud growth. It is noted that lifting is a key factor in the release of available potential instability on the High Plains.

  15. Probabilistic flood damage modelling at the meso-scale

    NASA Astrophysics Data System (ADS)

    Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

    2014-05-01

    Decisions on flood risk management and adaptation are usually based on risk analyses. Such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments. Most damage models have in common that complex damaging processes are described by simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood damage models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we show how the model BT-FLEMO (Bagging decision Tree based Flood Loss Estimation MOdel) can be applied on the meso-scale, namely on the basis of ATKIS land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany. The application of BT-FLEMO provides a probability distribution of estimated damage to residential buildings per municipality. Validation is undertaken on the one hand via a comparison with eight other damage models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official damage data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of damage estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation model BT-FLEMO is that it inherently provides quantitative information about the uncertainty of the prediction. Reference: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64.

  16. Meso-scale modeling of irradiated concrete in test reactor

    DOE PAGESBeta

    Giorla, Alain B.; Vaitová, M.; Le Pape, Yann; Štemberk, P.

    2015-10-18

    In this paper, we detail a numerical model accounting for the effects of neutron irradiation on concrete at the mesoscale. Irradiation experiments in test reactor (Elleuch et al.,1972), i.e., in accelerated conditions, are simulated. Concrete is considered as a two-phase material made of elastic inclusions (aggregate) subjected to thermal and irradiation-induced swelling and embedded in a cementitious matrix subjected to shrinkage and thermal expansion. The role of the hardened cement paste in the post-peak regime (brittle-ductile transition with decreasing loading rate), and creep effects are investigated. Radiation-induced volumetric expansion (RIVE) of the aggregate cause the development and propagation of damagemore » around the aggregate which further develops in bridging cracks across the hardened cement paste between the individual aggregate particles. The development of damage is aggravated when shrinkage occurs simultaneously with RIVE during the irradiation experiment. The post-irradiation expansion derived from the simulation is well correlated with the experimental data and, the obtained damage levels are fully consistent with previous estimations based on a micromechanical interpretation of the experimental post-irradiation elastic properties (Le Pape et al.,2015). In conclusion, the proposed modeling opens new perspectives for the interpretation of test reactor experiments in regards to the actual operation of light water reactors.« less

  17. Meso-scale modeling of irradiated concrete in test reactor

    SciTech Connect

    Giorla, Alain B.; Vaitová, M.; Le Pape, Yann; Štemberk, P.

    2015-10-18

    In this paper, we detail a numerical model accounting for the effects of neutron irradiation on concrete at the mesoscale. Irradiation experiments in test reactor (Elleuch et al.,1972), i.e., in accelerated conditions, are simulated. Concrete is considered as a two-phase material made of elastic inclusions (aggregate) subjected to thermal and irradiation-induced swelling and embedded in a cementitious matrix subjected to shrinkage and thermal expansion. The role of the hardened cement paste in the post-peak regime (brittle-ductile transition with decreasing loading rate), and creep effects are investigated. Radiation-induced volumetric expansion (RIVE) of the aggregate cause the development and propagation of damage around the aggregate which further develops in bridging cracks across the hardened cement paste between the individual aggregate particles. The development of damage is aggravated when shrinkage occurs simultaneously with RIVE during the irradiation experiment. The post-irradiation expansion derived from the simulation is well correlated with the experimental data and, the obtained damage levels are fully consistent with previous estimations based on a micromechanical interpretation of the experimental post-irradiation elastic properties (Le Pape et al.,2015). In conclusion, the proposed modeling opens new perspectives for the interpretation of test reactor experiments in regards to the actual operation of light water reactors.

  18. DEVELOPMENT OF MESOSCALE AIR QUALITY SIMULATION MODELS. VOLUME 5. USER'S GUIDE TO THE MESOFILE POSTPROCESSING PACKAGE

    EPA Science Inventory

    The MESOscale FILE management and analysis package (MESOFILE) is a highly flexible postprocessing system designed especially for interface with the MESOPLUME, MESOPUFF, and MESOGRID regional-scale air quality models, and the MESOPAC meteorology package. The MESOFILE package is co...

  19. URBAN MORPHOLOGICAL ANALYSIS FOR MESOSCALE METEOROLOGICAL AND DISPERSION MODELING APPLICATIONS: CURRENT ISSUES

    EPA Science Inventory

    Representing urban terrain characteristics in mesoscale meteorological and dispersion models is critical to produce accurate predictions of wind flow and temperature fields, air quality, and contaminant transport. A key component of the urban terrain representation is the charac...

  20. STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS

    SciTech Connect

    Anter El-Azab

    2013-04-08

    The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation motion and dislocation interaction in the crystal. Part of this effort also targeted the theoretical basis for establishing the connection between discrete and continuum representation of dislocations and the analysis of discrete dislocation simulation results within the continuum framework. This part of the research enables the enrichment of the kinetic description with information representing the discrete dislocation systems behavior. The third task focused on the development of physics-inspired numerical methods of solution of the coupled

  1. Mesoscale Model Validation using Stable Water Isotopes: The isoWATFLOOD Model

    NASA Astrophysics Data System (ADS)

    Stadnyk, T.; Kouwen, N.; Edwards, T.; Gibson, J.; Pietroniro, A.

    2009-05-01

    A methodology to improve mesoscale model validation is developed by calibrating simulations of both water and isotope mass simultaneously. The isoWATFLOOD model simulates changes in oxygen-18 of streamflow and hydrological processes contributing to streamflow. The added constraint of simulated to measured delta oxygen-18 in streamflow lowers the models degrees of freedom and generates more physically-based model parameterizations. Modelled results are shown to effectively reduce and constrain errors associated with equifinality in streamflow generation, providing a practical new approach for the assessment of mesoscale modelling. The WATFLOOD model is a conceptually-based distributed hydrological model used for simulating streamflow on mesoscale watersheds. Given the model's intended application to mesoscale hydrology, it remains crucial to ensure conceptualizations are physically representative of the hydrologic cycle and the natural environment. Building upon the existing flowpath-separation module within WATFLOOD, the capability to simulate changes in oxygen-18 through each component of the hydrological cycle is introduced. Masses of heavy-isotope are computed for compartmental storages; compartmental flows transfer flux-weighted portions of isotope mass between storages; and mass outflows from each compartment simultaneously combine to form the resultant channel flow composition. Heavy-isotope compositions are enriched when storages undergo evaporation resulting from the loss of isotopically-depleted vapour described by the well-known Craig & Gordon isotopic fractionation model. The isoWATFLOOD model is forced by oxygen-18 in rain, oxygen-18 in snow, and relative humidity; and requires no additional parameterizations of WATFLOOD. The first mesoscale, continuous simulations of changes in oxygen-18 in streamflow are presented for the remote Fort Simpson basin in Northwest Territories, Canada and for the largely populated Grand River Basin in south western Ontario

  2. Mesoscale numerical modeling of plastic bonded explosives under shock loading

    NASA Astrophysics Data System (ADS)

    Shang, Hailin; Zhao, Feng; Ji, Guangfu; Fu, Hua

    2015-09-01

    Mesoscale responses of plastic bonded explosives under shock loading are investigated using material point method as implemented in the Uintah Computational Framework. The two-dimensional geometrical model which can approximately reflect the mesoscopic structure of plastic bonded explosives was created based on the Voronoi tessellation. Shock loading for the explosive was performed by a piston moving at a constant velocity. For the purpose of investigating the influence of shock strength on the responses of explosives, two different velocities for the piston were used, 200 m/s and 400 m/s, respectively. The simulation results indicate that under shock loading there forms some stress localizations on the grain boundary of explosive. These stress localizations lead to large plastic deformations, and the plastic strain energy transforms to thermal energy immediately, causing temperature to rise rapidly and form some hot spots on grain boundary areas. The comparison between two different piston velocities shows that with increasing shock strength, the distribution of plastic strain and temperature does not have significant change, but their values increase obviously. Namely, the higher the shock strength is, the higher the hot spot temperature will be.

  3. Nested Logit Models for Multiple-Choice Item Response Data

    ERIC Educational Resources Information Center

    Suh, Youngsuk; Bolt, Daniel M.

    2010-01-01

    Nested logit item response models for multiple-choice data are presented. Relative to previous models, the new models are suggested to provide a better approximation to multiple-choice items where the application of a solution strategy precedes consideration of response options. In practice, the models also accommodate collapsibility across all…

  4. Advances in CBL Budgetting and Inverse Modelling by Applying an Off-the-shelf Mesoscale Model

    NASA Astrophysics Data System (ADS)

    van der Molen, M. K.; Dolman, H.; Ronda, R. J.

    2005-12-01

    Eddy flux towers measure carbon sinks/sources at a local scale (~0.1 km), with the CBL budget method fluxes may be determined at a landscape scale (~1 km), and inverse models may determine the source/sink distribution at a global/continental scale (~1000-10000 km). Although currently efforts are made to increase the resolution of inverse models to the regional scale (~100 km), the meso-scale (100-1000 km) is rather badly represented in this spectrum of approaches. Boundary layer profiles contain signatures of mesoscale processes, such as the effect of wind divergence, topography and forest breezes on the boundary layer height and the subsidence velocity. 3-D advection of resulting concentration gradients is one of the main reasons of failure of the CBL budget approach and the representation error in inverse models and may be addressed in mesoscale atmospheric models. This study shows that considerable improvement may be obtained in the interpretation of boundary layer profiles by running an off-the-shelf mesoscale model without detailed prior knowlegde of the surface flux distribution. The simulations were carried out in the region around Zotino, Central Siberia to aid the interpretation of profile observations collected as part of TCOS-Siberia.

  5. A concurrent precursor inflow method for LES of atmospheric boundary layer flows with variable inflow direction for coupling with meso-scale models

    NASA Astrophysics Data System (ADS)

    Munters, Wim; Meneveau, Charles; Meyers, Johan

    2014-11-01

    In order to incorporate multiple scales of meteorological phenomena in atmospheric simulations, subsequent nesting of meso-scale models is often used. However, the spatial and temporal resolution in such models is too coarse to resolve the three-dimensional turbulent eddies that are characteristic for atmospheric boundary layer flows. This motivates the development of tools to couple meso-scale models to Large-Eddy Simulations (LES), in which turbulent fluctuations are explicitly resolved. A major challenge in this area is the spin-up region near the inlet of the LES in which the flow has to evolve from a RANS-like inflow, originating from the meso-scale model, to a fully turbulent velocity field. We propose a generalized concurrent precursor inflow method capable of imposing boundary conditions for time-varying inflow directions. The method is based on a periodic fully-developed precursor boundary-layer simulation that is dynamically rotated with the wind direction that drives the main LES. In this way realistic turbulent inflow conditions are applied while still retaining flexibility to dynamically adapt to meso-scale variations in wind directions. Applications to wind simulations with varying inflow directions, and comparisons to conventional coupling methods are shown. Work supported by ERC (ActiveWindFarms, Grant No: 306471). CM is supported by NSF (Grant No. 1243482).

  6. Mesoscale thermal model for urban heat island mitigation

    NASA Astrophysics Data System (ADS)

    Silva, Humberto Ramon

    A simple energy balance model is created for use in developing mitigation strategies for the Urban Heat Island (UHI) effect. The model is applied to the city of Phoenix, Arizona, USA. There are six primary contributions to the overall energy balance: incident solar radiation, anthropogenic heat input, conduction heat loss, outgoing evapotranspiration, outgoing convection, and outgoing emitted radiation. The model temperature is shown to have the same periodic behavior as the experimentally measured air temperatures. The present model, while maintaining valid energy-balance physics, allows users to quickly and easily predict the relative effects of urban heat island mitigation measures. Accordingly, this model is applied here to show the relative effects of four common mitigation strategies: increasing the overall (1) emissivity, (2) percentage of vegetated area, (3) thermal conductivity, and (4) albedo of the urban environment in a series of percentage increases by 5, 10, 15, and 20 percent from baseline values. In addition to modeling mitigation strategies, the model is utilized to evaluate human health vulnerability from excessive heat-related events, based on heat-related emergency service data from 2002 to 2006. The four modeled UHI mitigation strategies, taken in combination, would lead to a 48 percent reduction in annual heat-related emergency service calls, where increasing the albedo is the single most effective UHI mitigation strategy. Finally, a spatial superposition design is presented that couples this model with the more robust fifth-generation Pennsylvania State University - National Center for Atmospheric Research Mesoscale Model (MM5). As a result, a new hypothesis is conceived which states that perturbation values from the norm temperature do not change when certain mitigation strategies are imposed. It is shown from demonstrative spatial mitigation schemes that having a fewer number of mitigated points (by almost half) on a square urban grid in

  7. Evaluating the extreme precipitation events using a mesoscale atmopshere model

    NASA Astrophysics Data System (ADS)

    Yucel, I.; Onen, A.

    2012-04-01

    Evidence is showing that global warming or climate change has a direct influence on changes in precipitation and the hydrological cycle. Extreme weather events such as heavy rainfall and flooding are projected to become much more frequent as climate warms. Mesoscale atmospheric models coupled with land surface models provide efficient forecasts for meteorological events in high lead time and therefore they should be used for flood forecasting and warning issues as they provide more continuous monitoring of precipitation over large areas. This study examines the performance of the Weather Research and Forecasting (WRF) model in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in West Black Sea Region of Turkey. Extreme precipitation events usually resulted in flood conditions as an associated hydrologic response of the basin. The performance of the WRF system is further investigated by using the three dimensional variational (3D-VAR) data assimilation scheme within WRF. WRF performance with and without data assimilation at high spatial resolution (4 km) is evaluated by making comparison with gauge precipitation and satellite-estimated rainfall data from Multi Precipitation Estimates (MPE). WRF-derived precipitation showed capabilities in capturing the timing of the precipitation extremes and in some extent spatial distribution and magnitude of the heavy rainfall events. These precipitation characteristics are enhanced with the use of 3D-VAR scheme in WRF system. Data assimilation improved area-averaged precipitation forecasts by 9 percent and at some points there exists quantitative match in precipitation events, which are critical for hydrologic forecast application.

  8. An Overview of Mesoscale Material Modeling with Eulerian Hydrocodes

    NASA Astrophysics Data System (ADS)

    Benson, David

    2013-06-01

    Eulerian hydrocodes were originally developed for simulating strong shocks in solids and fluids, but their ability to handle arbitrarily large deformations and the formation of new free surfaces makes them attractive for simulating the deformation and failure of materials at the mesoscopic scale. A summary of some of the numerical techniques that have been developed to address common issues for this class of problems is presented with the shock compression of powders used as a model problem. Achieving the correct packing density with the correct statistical distribution of particle sizes and shapes is, in itself, a challenging problem. However, since Eulerian codes permit multiple materials within each element, or cell, the material interfaces do not have to follow the mesh lines. The use of digital image processing to map the pixels of micrographs to the Eulerian mesh has proven to be a popular and useful means of creating accurate models of complex microstructures. Micro CT scans have been used to extend this approach to three dimensions for several classes of materials. The interaction between the particles is of considerable interest. During shock compression, individual particles may melt and form jets, and the voids between them collapse. Dynamic interface ordering has become a necessity, and many codes now have a suite of options for handling multi-material mechanics. True contact algorithms are now replacing multi-material approximations in some cases. At the mesoscale, material properties often vary spatially due to sub-scale effects. Using a large number of material species to represent the variations is usually unattractive. Directly specifying the properties point-wise as history variables has not proven successful because the limiters in the transport algorithms quickly smooth out the variations. Circumventing the limiter problem is shown to be relatively simple with the use of a reference configuration and the transport of the initial coordinates

  9. Weather Research and Forecasting Model with Vertical Nesting Capability

    Energy Science and Technology Software Center (ESTSC)

    2014-08-01

    The Weather Research and Forecasting (WRF) model with vertical nesting capability is an extension of the WRF model, which is available in the public domain, from www.wrf-model.org. The new code modifies the nesting procedure, which passes lateral boundary conditions between computational domains in the WRF model. Previously, the same vertical grid was required on all domains, while the new code allows different vertical grids to be used on concurrently run domains. This new functionality improvesmore » WRF's ability to produce high-resolution simulations of the atmosphere by allowing a wider range of scales to be efficiently resolved and more accurate lateral boundary conditions to be provided through the nesting procedure.« less

  10. Weather Research and Forecasting Model with Vertical Nesting Capability

    SciTech Connect

    2014-08-01

    The Weather Research and Forecasting (WRF) model with vertical nesting capability is an extension of the WRF model, which is available in the public domain, from www.wrf-model.org. The new code modifies the nesting procedure, which passes lateral boundary conditions between computational domains in the WRF model. Previously, the same vertical grid was required on all domains, while the new code allows different vertical grids to be used on concurrently run domains. This new functionality improves WRF's ability to produce high-resolution simulations of the atmosphere by allowing a wider range of scales to be efficiently resolved and more accurate lateral boundary conditions to be provided through the nesting procedure.

  11. Observation Denial and Performance of a Local Mesoscale Model

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III

    2009-01-01

    Forecasters at the 45th Weather Squadron (45 WS) use observations from the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) wind tower network and the CCAFS (XMR) daily rawinsonde observations (RAOB) to issue and verify wind advisories and warnings for operations. These observations are also used by the Spaceflight Meteorology Group (SMG) in Houston, Texas and the Melbourne, Florida National Weather Service office to initialize their locally run mesoscale models. SMG also uses the observations to support shuttle landings at the KSC Shuttie Landing Facility. Due to impending budget cuts, some or all of the KSC/CCAFS wind towers on the east-central Florida mainland and the XMR RAOBs may be eliminated. The loss of these data may impact the forecast capability of the 45 WS and SMG. The Applied Meteorology Unit (AMU) was tasked to conduct a modeling study to determine how important these observations are to the accuracy of the model output used by the forecasters as input to their forecasts. To accomplish this, the AMU performed a sensitivity study using the Weather Research and Forecasting (NRF) model initialized with and without KSC/CCAFS wind tower and XMR RAOB observations. The AMU assessed the accuracy of model output by comparing peak wind forecasts with operationally significant wind advisory and warning criteria forecast by the 45 WS. To assess model performance when initialized with and without some of the wind tower and XMR RAOB observations, the AMU conducted a subjective analysis by displaying model wind forecasts graphically with the observations overlaid for comparison and they conducted an objective analysis by comparing the maximum peak wind forecast to the maximum peak wind observed within the KSC/CCAFS wind tower network. Data were collected for twelve warm season cases and eight cool season cases from June - September 2007 and November - January 2008, respectively. For each case chosen, the 45 WS must have issued a wind advisory

  12. Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment

    SciTech Connect

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

    2005-03-18

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

  13. Mesoscale modelling of water vapour in the tropical UTLS: two case studies from the HIBISCUS campaign

    NASA Astrophysics Data System (ADS)

    Marécal, V.; Durry, G.; Longo, K.; Freitas, S.; Rivière, E. D.; Pirre, M.

    2006-08-01

    In this study, we evaluate the ability of the BRAMS mesoscale model compared to ECMWF global analysis to simulate the observed vertical variations of water vapour in the tropical upper troposphere and lower stratosphere (UTLS). The observations are balloon-borne measurements of water vapour mixing ratio and temperature from micro-SDLA (Tunable Diode Laser Spectrometer) instrument. Data from two balloon flights performed during the 2004 HIBISCUS field campaign are used to compare with the mesoscale simulations and to ECMWF analysis. The mesoscale model performs significantly better than ECMWF analysis for water vapour in the upper troposphere and similarly or slightly worse for temperature. The improvement provided by the mesoscale model for water vapour comes mainly from (i) the enhanced vertical resolution in the UTLS (250 m for BRAMS and ~1 km for ECMWF model) and (ii) the more detailed microphysical parameterization providing ice supersaturations as in the observations. The ECMWF vertical resolution (~1 km) is too coarse to capture the observed fine scale vertical variations of water vapour in the UTLS. In near saturated or supersaturated layers, the mesoscale model relative humidity with respect to ice saturation is close to observations provided that the temperature profile is realistic. For temperature, ECMWF analysis gives good results partly thanks to data assimilation. The analysis of the mesoscale model results showed that in undersaturated layers, the water vapour profile depends mainly on the dynamics. In saturated/supersaturated layers, microphysical processes play an important role and have to be taken into account on top of the dynamical processes to understand the water vapour profiles. In the lower stratosphere, the ECMWF model and the BRAMS model give very similar water vapour profiles that are significantly dryer than micro-SDLA measurements. This similarity comes from the fact that BRAMS is initialised using ECMWF analysis and that no mesoscale

  14. 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.

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.; Pielke, Roger A.

    1996-03-01

    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 the transport and diffusion of a perfluorocarbon tracer-gas cloud for one afternoon surface release during the July 1980 Great Plains mesoscale tracer field experiment. Ground-level concentration (GLC) measurements taken along arcs of samplers 100 and 600 km downwind of the release site at Norman, Oklahoma, up to three days after the tracer release were available for comparison. Quantitative measures of a number of significant dispersion characteristics obtained from analysis of the observed tracer cloud's moving GLC `footprint' have been used to evaluate the modeling system's skill in simulating this MAD case.MAD is more dependent upon the spatial and temporal structure of the transport wind field than is short-range atmospheric dispersion. For the Great Plains mesoscale tracer experiment, the observations suggest that the Great Plains nocturnal low-level jet played an important role in transporting and deforming the tracer cloud. A suite of ten two- and three-dimensional numerical meteorological experiments was devised to investigate the relative contributions of topography, other surface inhomogeneities, atmospheric baroclinicity, synoptic-scale flow evolution, and meteorological model initialization time to the structure and evolution of the low-level mesoscale flow field and thus to MAD. Results from the ten mesoscale meteorological simulations are compared in this part of the paper. The predicted wind fields display significant differences, which give rise in turn to significant differences in predicted low-level transport. The presence of an oscillatory ageostrophic component in the observed synoptic low-level winds for this case is shown to complicate initialization of the meteorological model considerably and is the

  15. A nested grid, nonhydrostatic, elastic model using a terrain-following coordinate transformation - The radiative-nesting boundary conditions

    NASA Technical Reports Server (NTRS)

    Chen, Chaing

    1991-01-01

    This study presents a nested-grid nonhydrostatic and elastic model using a terrain-following coordinate transformation as well as a unique application of grid-nesting techniques to the time-splitting elastic model. A simulation of the 10-m-high Witch of Agnesi Mountain provides the control to test this new model. The results show that the model produces the same solution as that derived from a simple linear analytic model. It is demonstrated that the new nested-grid model improves model resolution without resorting to the costly method of placing a fine-resolution grid over the entire domain. Since the wave reflection from the boundaries of the fine-grid model is well controlled, the boundary of the nested fine-grid model can be located even at the wave-active region. The model can be used to simulate various weather systems in which scale interactions are important.

  16. Two-dimensional simulations of possible mesoscale effects of nuclear war fires: 1. Model description

    NASA Astrophysics Data System (ADS)

    Giorgi, Filippo

    1989-01-01

    In this paper and the companion paper by Giorgi and Visconti [this issue] a two-dimensional mesoscale meteorological model is coupled to an aerosol model to investigate possible mesoscale effects of nuclear war fires. The meteorological model used in this study is a two-dimensional analog of the Penn State/NCAR mesoscale model with enhancements in the areas of radiative transfer, surface physics, and moisture physics. The aerosol model solves equations for the hygroscopic and hydrophobic fractions of particulate material and includes particle transport, sedimentation, dry-deposition, in-cloud and below-cloud scavenging, and a first order term accounting for aerosol aging. In this paper the meteorological model and the aerosol model are first described and then applied, as an illustrative example, to a simulation of the development of sea-breezelike circulations induced by contrasts in soil moisture available for evaporation.

  17. Two-dimensional simulations of possible mesoscale effects of nuclear war fires 1. Model description

    SciTech Connect

    Giorgi, F.

    1989-01-20

    In this paper and the companion paper by Giorgi and Visconti (this issue) a two-dimensional mesoscale meteorological model is coupled to an aerosol model to investigate possible mesoscale effects of nuclear war fires. The meteorological model used in this study is a two-dimensional analog of the Penn State/NCAR mesoscale model with enhancements in the areas of radiative transfer, surface physics, and moisture physics. The aerosol model solves equations for the hygroscopic and hydrophobic fractions of particulate material and includes particle transport, sedimentation, dry-deposition, in-cloud and below-cloud scavenging, and a first order term accounting for aerosol aging. In this paper the meteorological model and the aerosol model are first described and then applied, as an illustrative example, to a simulation of the development of sea-breezelike circulations induced by contrasts in soil moisture available for evaporation. copyright American Geophysical Union 1989

  18. Interpreting the suspended sediment dynamics in a mesoscale river basin of Central Mexico using a nested watershed approach

    NASA Astrophysics Data System (ADS)

    Duvert, C.; Némery, J.; Gratiot, N.; Prat, C.; Collet, L.; Esteves, M.

    2009-12-01

    at the outlet, with a dominance of cohesive sediments (mainly silt and clay). Sediment delivery dynamics was found to be seasonally dependent and principally driven by the river network transport capacity. With the exception of events associated with a very high discharge peak, sub-catchments delivered very little sediment to the basin’s outlet during first events of the rainy season (corresponding to May-June period). Later on (from July until the end of the season), even low headwater sediment peaks were coupled with significant sediment fluxes at the outlet. An analysis of SSC-Q hysteresis patterns was also conducted for major flood events at each site. Anti-clockwise SSC-Q hysteresis loops were recorded most frequently at the three upland sub-catchments, while at the outlet a double-peaked SSC signal was repeatedly detected, outlining the variety in sediment contributions. The findings of this nested watershed approach suggest that during the first part of the rainy season, fine sediment loads exported from active hillslopes deposit as fluid mud layers in the lowland river channels. Once the in-channel storage capacity is loaded, the river transport potential guarantees a direct transit between headwater areas and delivery zones.

  19. Large-eddy simulation coupled to mesoscale meteorological model for gas dispersion in an urban district

    NASA Astrophysics Data System (ADS)

    Michioka, T.; Sato, A.; Sada, K.

    2013-08-01

    A microscale large-eddy simulation (LES) model coupled to a mesoscale LES model is implemented to estimate a ground concentration considering the meteorological influence in an actual urban district. The microscale LES model is based on a finite volume method with an unstructured grid system to resolve the flow structure in a complex geometry. The Advanced Regional Prediction System (ARPS) is used for mesoscale meteorological simulation. To evaluate the performance of the LES model, 1-h averaged concentrations are compared with those obtained by field measurements, which were conducted for tracer gas dispersion from a point source on the roof of a tall building in Tokyo. The concentrations obtained by the LES model without combing the mesoscale LES model are in quite good agreement with the wind-tunnel experimental data, but overestimates the 1 h averaged ground concentration in the field measurements. On the other hand, the ground concentrations using the microscale LES model coupled to the mesoscale LES are widely distributed owing to large-scale turbulent motions generated by the mesoscale LES, and the concentrations are nearly equal to the concentrations from the field measurements.

  20. Assessing the interaction of mountain waves and katabatic flows using a mesoscale model

    SciTech Connect

    Poulos, G.S.; Bossert, J.E.; McKee, T.B.; Pielke, A.

    1996-07-01

    This paper has two main purposes. The first is to evaluate the interaction of two common complex terrain meteorological phenomena, katabatic flow and mountain waves. Although occasionally investigated together, generally, the large body of literature regarding them has treated each individually. The second purpose is to show the reader the utility of extracting high time resolution data sets of (1) standard meteorological variables, and (2) seldom used, components of the model equations. Using such time series, significant variability is found in the evolving, clear sky, nocturnal boundary layer, when meteorological variability is generally considered to be at its lowest point diurnally. The approach is to use results from three, 3-d, realistic topography simulations produced by the Regional Atmospheric Modeling System (RAMS). RAMS is a primitive equation mesoscale model formulated in {sigma} coordinates. The model is set up with five nested grids that focus on Eldorado Canyon, which is embedded in the Front Range slope of Colorado. On the finest grid {Delta}x = {Delta}y = 400 m and {Delta}z = 20 m for the lowest 400 m above ground level (AGL). The three simulations were: (1) a realistic simulation; (2) the same as (1) but without radiative forcing (referred to as mountain wave only or MWO) and (3) the same as (1) but without boundary nudging and no initial winds (referred to as katabatic flow only or KFO). The case night is 3--4 Sep 1993 from the Atmospheric Studies in Complex Terrain (ASCOT) 1993 field program near Rocky Flats, Colorado. Both mountain waves and katabatic flows were occurring on this night.

  1. A Study of Mesoscale Gravity Waves over the North Atlantic with Satellite Observations and a Mesoscale Model

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.; Zhang, Fuqing

    2004-01-01

    Satellite microwave data are used to study gravity wave properties and variabilities over the northeastern United States and the North Atlantic in the December-January periods. The gravity waves in this region, found in many winters, can reach the stratopause with growing amplitude. The Advanced Microwave Sounding Unit-A (AMSU-A) observations show that the wave occurrences are correlated well with the intensity and location of the tropospheric baroclinic jet front systems. To further investigate the cause(s) and properties of the North Atlantic gravity waves, we focus on a series of wave events during 19-21 January 2003 and compare AMSU-A observations to simulations from a mesoscale model (MM5). The simulated gravity waves compare qualitatively well with the satellite observations in terms of wave structures, timing, and overall morphology. Excitation mechanisms of these large-amplitude waves in the troposphere are complex and subject to further investigations.

  2. A Nonparametric Bayesian Model for Nested Clustering.

    PubMed

    Lee, Juhee; Müller, Peter; Zhu, Yitan; Ji, Yuan

    2016-01-01

    We propose a nonparametric Bayesian model for clustering where clusters of experimental units are determined by a shared pattern of clustering another set of experimental units. The proposed model is motivated by the analysis of protein activation data, where we cluster proteins such that all proteins in one cluster give rise to the same clustering of patients. That is, we define clusters of proteins by the way that patients group with respect to the corresponding protein activations. This is in contrast to (almost) all currently available models that use shared parameters in the sampling model to define clusters. This includes in particular model based clustering, Dirichlet process mixtures, product partition models, and more. We show results for two typical biostatistical inference problems that give rise to clustering. PMID:26519174

  3. Numerical Model Studies of the Martian Mesoscale Circulations

    NASA Technical Reports Server (NTRS)

    Segal, M.; Arritt, R. W.

    1996-01-01

    Studies concerning mesoscale topographical effects on Martian flows examined low-level jets in the near equatorial latitudes and the dynamical intensification of flow by steep terrain. Continuation of work from previous years included evaluating the dissipation of cold air mass outbreaks due to enhanced sensible heat flux, further sensitivity and scaling evaluations for generalization of the characteristics of Martian mesoscale circulation caused by horizontal sensible heat-flux gradients, and evaluations of the significance that non-uniform surface would have on enhancing the polar CO2 ice sublimation during the spring. The sensitivity of maximum and minimum atmospheric temperatures to changes in wind speed, surface albedo, and deep soil temperature was investigated.

  4. A two-moment bulk microphysics coupled with a mesoscale model WRF: Model description and first results

    NASA Astrophysics Data System (ADS)

    Gao, Wenhua; Zhao, Fengsheng; Hu, Zhijin; Feng, Xuan

    2011-09-01

    The Chinese Academy of Meteorological Sciences (CAMS) two-moment bulk microphysics scheme was adopted in this study to investigate the representation of cloud and precipitation processes under different environmental conditions. The scheme predicts the mixing ratio of water vapor as well as the mixing ratios and number concentrations of cloud droplets, rain, ice, snow, and graupel. A new parameterization approach to simulate heterogeneous droplet activation was developed in this scheme. Furthermore, the improved CAMS scheme was coupled with the Weather Research and Forecasting model (WRF v3.1), which made it possible to simulate the microphysics of clouds and precipitation as well as the cloud-aerosol interactions in selected atmospheric condition. The rain event occurring on 27-28 December 2008 in eastern China was simulated using the CAMS scheme and three sophisticated microphysics schemes in the WRF model. Results showed that the simulated 36-h accumulated precipitations were generally agreed with observation data, and the CAMS scheme performed well in the southern area of the nested domain. The radar reflectivity, the averaged precipitation intensity, and the hydrometeor mixing ratios simulated by the CAMS scheme were generally consistent with those from other microphysics schemes. The hydrometeor number concentrations simulated by the CAMS scheme were also close to the experiential values in stratus clouds. The model results suggest that the CAMS scheme performs reasonably well in describing the microphysics of clouds and precipitation in the mesoscale WRF model.

  5. Modeling pulse characteristics in Xenon with NEST

    NASA Astrophysics Data System (ADS)

    Mock, J.; Barry, N.; Kazkaz, K.; Stolp, D.; Szydagis, M.; Tripathi, M.; Uvarov, S.; Woods, M.; Walsh, N.

    2014-04-01

    A comprehensive model for describing the characteristics of pulsed signals, generated by particle interactions in xenon detectors, is presented. An emphasis is laid on two-phase time projection chambers, but the models presented are also applicable to single phase detectors. In order to simulate the pulse shape due to primary scintillation light, the effects of the ratio of singlet and triplet dimer state populations, as well as their corresponding decay times, and the recombination time are incorporated into the model. In a two phase time projection chamber, when simulating the pulse caused by electroluminescence light, the ionization electron mean free path in gas, the drift velocity, singlet and triplet decay times, diffusion constants, and the electron trapping time, have been implemented. This modeling has been incorporated into a complete software package, which realistically simulates the expected pulse shapes for these types of detectors.

  6. Intercomparison of state-of-the-art models for wind energy resources with mesoscale models:

    NASA Astrophysics Data System (ADS)

    Olsen, Bjarke Tobias; Hahmann, Andrea N.; Sempreviva, Anna Maria; Badger, Jake; Joergensen, Hans E.

    2016-04-01

    1. Introduction Mesoscale models are increasingly being used to estimate wind conditions to identify perspective areas and sites where to develop wind farm projects. Mesoscale models are functional for giving information over extensive areas with various terrain complexities where measurements are scarce and measurement campaigns costly. Several mesoscale models and families of models are being used, and each often contains thousands of setup options. Since long-term integrations are expensive and tedious to carry out, only limited comparisons exist. To remedy this problem and for evaluating the capabilities of mesoscale models to estimate site wind conditions, a tailored benchmarking study has been co-organized by the European Wind Energy Association (EWEA) and the European Energy Research Alliance Joint Programme Wind Energy (EERA JP WIND). EWEA hosted results and ensured that participants were anonymous. The blind evaluation was performed at the Wind Energy Department of the Technical University of Denmark (DTU) with the following objectives: (1) To highlight common issues on mesoscale modelling of wind conditions on sites with different characteristics, and (2) To identify gaps and strengths of models and understand the root conditions for further evaluating uncertainties. 2. Approach Three experimental sites were selected: FINO 3 (offshore, GE), Høvsore (coastal, DK), and Cabauw (land-based, NL), and three other sites without observations based on . The three mast sites were chosen because the availability of concurrent suitable time series of vertical profiles of winds speed and other surface parameters. The participants were asked to provide hourly time series of wind speed, wind direction, temperature, etc., at various vertical heights for a complete year. The methodology used to derive the time series was left to the choice of the participants, but they were asked for a brief description of their model and many other parameters (e.g., horizontal and

  7. Overshooting convection during TRO-pico: mesoscale modelling of two cases hydrating the lower stratosphere

    NASA Astrophysics Data System (ADS)

    Rivière, Emmanuel; Marécal, Virginie; Khaykin, Sergey; Amarouche, Nadir; Ghysels, Mélanie; Mappe-Fogaing, Irène; Behera, Abhinna; Held, Gerhard; França, Hermes

    2016-04-01

    One of the main aims of the TRO-pico project (2010-2015) was to study the variability of overshooting convection at the local scale to try to deduce a typical impact on the TTL water at the global scale. In this study, we've identified local maximum in the water vapour profiles gathered by the balloon-borne hygrometers Pico-SDLA and Flash above Bauru, Brazil (22.3 S) during the TRO-pico campaign. We tried to link them to overshooting cells in the surrounding of Bauru with a trajectory analysis. In this study we select a couple of cases of overshooting convection both sampled by the Bauru S-Band radar and by one of the balloon-borne instruments of the TRO-pico campaign in 2012 and 2013. The selected cases are the case of March 13, 2012 (hereafter M12), sounded by both hygrometers Pico-SDLA and FLASH, and the case of January 26, 2013 (hereafter J13), sounded by Pico-SDLA. For the M12 case, local water vapour enhancements at two different altitudes due to two different cells were reported, with local enhancement of about 0.65 ppmv. For the J26 case, the water enhancement was about 1 ppmv. The corresponding mesoscale simulations with the Brazilian Regional Atmospheric Modelling System (BRAMS) using 3 nested grids with horizontal resolution down to 800 m were carried out. Simulation results are compared to Bauru's radar echo tops and and water vapour in situ measurements. As for the M12 simulation, the model is doing a rather good job in reproducing several overshooting cells, both in severity and timing. Associated stratospheric water budget are computed for each cases.

  8. Case study modeling of turbulent and mesoscale fluxes over the BOREAS region

    USGS Publications Warehouse

    Vidale, P.L.; Pielke, R.A., Sr.; Steyaert, L.T.; Barr, A.

    1997-01-01

    Results from aircraft and surface observations provided evidence for the existence of mesoscale circulations over the Boreal Ecosystem-Atmosphere Study (BOREAS) domain. Using an integrated approach that included the use of analytical modeling, numerical modeling, and data analysis, we have found that there are substantial contributions to the total budgets of heat over the BOREAS domain generated by mesoscale circulations. This effect is largest when the synoptic flow is relatively weak, yet it is present under less favorable conditions, as shown by the case study presented here. While further analysis is warranted to document this effect, the existence of mesoscale flow is not surprising, since it is related to the presence of landscape patches, including lakes, which are of a size on the order of the local Rossby radius and which have spatial differences in maximum sensible heat flux of about 300 W m-2. We have also analyzed the vertical temperature profile simulated in our case study as well as high-resolution soundings and we have found vertical profiles of temperature change above the boundary layer height, which we attribute in part to mesoscale contributions. Our conclusion is that in regions with organized landscapes, such as BOREAS, even with relatively strong synoptic winds, dynamical scaling criteria should be used to assess whether mesoscale effects should be parameterized or explicitly resolved in numerical models of the atmosphere.

  9. Integrating Visualizations into Modeling NEST Simulations

    PubMed Central

    Nowke, Christian; Zielasko, Daniel; Weyers, Benjamin; Peyser, Alexander; Hentschel, Bernd; Kuhlen, Torsten W.

    2015-01-01

    Modeling large-scale spiking neural networks showing realistic biological behavior in their dynamics is a complex and tedious task. Since these networks consist of millions of interconnected neurons, their simulation produces an immense amount of data. In recent years it has become possible to simulate even larger networks. However, solutions to assist researchers in understanding the simulation's complex emergent behavior by means of visualization are still lacking. While developing tools to partially fill this gap, we encountered the challenge to integrate these tools easily into the neuroscientists' daily workflow. To understand what makes this so challenging, we looked into the workflows of our collaborators and analyzed how they use the visualizations to solve their daily problems. We identified two major issues: first, the analysis process can rapidly change focus which requires to switch the visualization tool that assists in the current problem domain. Second, because of the heterogeneous data that results from simulations, researchers want to relate data to investigate these effectively. Since a monolithic application model, processing and visualizing all data modalities and reflecting all combinations of possible workflows in a holistic way, is most likely impossible to develop and to maintain, a software architecture that offers specialized visualization tools that run simultaneously and can be linked together to reflect the current workflow, is a more feasible approach. To this end, we have developed a software architecture that allows neuroscientists to integrate visualization tools more closely into the modeling tasks. In addition, it forms the basis for semantic linking of different visualizations to reflect the current workflow. In this paper, we present this architecture and substantiate the usefulness of our approach by common use cases we encountered in our collaborative work. PMID:26733860

  10. Sensitivity of a mesoscale model to initial specification of relative humidity, liquid water and vertical motion

    NASA Technical Reports Server (NTRS)

    Kalb, M. W.; Perkey, D. J.

    1985-01-01

    The influence of synoptic scale initial conditions on the accuracy of mesoscale precipitation modeling is investigated. Attention is focused on the relative importance of the water vapor, cloud water, rain water, and vertical motion, with the analysis carried out using the Limited Area Mesoscale Prediction System (LAMPS). The fully moist primitive equation model has 15 levels and a terrain-following sigma coordinate system. A K-theory approach was implemented to model the planetary boundary layer. A total of 15 sensitivity simulations were run to investigate the effects of the synoptic initial conditions of the four atmospheric variables. The absence of synoptic cloud and rain water amounts in the initialization caused a 2 hr delay in the onset of precipitation. The delay was increased if synoptic-scale vertical motion was used instead of mesoscale values. Both the delays and a choice of a smoothed moisture field resulted in underestimations of the total rainfall.

  11. Network-based model of the growth of termite nests

    NASA Astrophysics Data System (ADS)

    Eom, Young-Ho; Perna, Andrea; Fortunato, Santo; Darrouzet, Eric; Theraulaz, Guy; Jost, Christian

    2015-12-01

    We present a model for the growth of the transportation network inside nests of the social insect subfamily Termitinae (Isoptera, termitidae). These nests consist of large chambers (nodes) connected by tunnels (edges). The model based on the empirical analysis of the real nest networks combined with pruning (edge removal, either random or weighted by betweenness centrality) and a memory effect (preferential growth from the latest added chambers) successfully predicts emergent nest properties (degree distribution, size of the largest connected component, average path lengths, backbone link ratios, and local graph redundancy). The two pruning alternatives can be associated with different genuses in the subfamily. A sensitivity analysis on the pruning and memory parameters indicates that Termitinae networks favor fast internal transportation over efficient defense strategies against ant predators. Our results provide an example of how complex network organization and efficient network properties can be generated from simple building rules based on local interactions and contribute to our understanding of the mechanisms that come into play for the formation of termite networks and of biological transportation networks in general.

  12. Network-based model of the growth of termite nests.

    PubMed

    Eom, Young-Ho; Perna, Andrea; Fortunato, Santo; Darrouzet, Eric; Theraulaz, Guy; Jost, Christian

    2015-12-01

    We present a model for the growth of the transportation network inside nests of the social insect subfamily Termitinae (Isoptera, termitidae). These nests consist of large chambers (nodes) connected by tunnels (edges). The model based on the empirical analysis of the real nest networks combined with pruning (edge removal, either random or weighted by betweenness centrality) and a memory effect (preferential growth from the latest added chambers) successfully predicts emergent nest properties (degree distribution, size of the largest connected component, average path lengths, backbone link ratios, and local graph redundancy). The two pruning alternatives can be associated with different genuses in the subfamily. A sensitivity analysis on the pruning and memory parameters indicates that Termitinae networks favor fast internal transportation over efficient defense strategies against ant predators. Our results provide an example of how complex network organization and efficient network properties can be generated from simple building rules based on local interactions and contribute to our understanding of the mechanisms that come into play for the formation of termite networks and of biological transportation networks in general. PMID:26764747

  13. a Mesoscale Atmospheric Dispersion Modeling System for Simulations of Topographically Induced Atmospheric Flow and Air Pollution Dispersion.

    NASA Astrophysics Data System (ADS)

    Boybeyi, Zafer

    A mesoscale atmospheric dispersion modeling system has been developed to investigate mesoscale circulations and associated air pollution dispersion, including effects of terrain topography, large water bodies and urban areas. The system is based on a three-dimensional mesoscale meteorological model coupled with two dispersion models (an Eulerian dispersion model and a Lagrangian particle dispersion model). The mesoscale model is hydrostatic and based on primitive equations formulated in a terrain-following coordinate system with a E-varepsilon turbulence closure scheme. The Eulerian dispersion model is based on numerical solution of the advection-diffusion equation to allow one to simulate releases of non-buoyant pollutants (especially from area and volume sources). The Lagrangian particle dispersion model allows one to simulate releases of buoyant pollutants from arbitrary sources (particularly from point and line sources). The air pollution dispersion models included in the system are driven by the meteorological information provided by the mesoscale model. Mesoscale atmospheric circulations associated with sea and lake breezes have been examined using the mesoscale model. A series of model sensitivity studies were performed to investigate the effects of different environmental parameters on these circulations. It was found that the spatial and temporal variation of the sea and lake breeze convergence zones and the associated convective activities depend to a large extent on the direction and the magnitude of the ambient wind. Dispersion of methyl isocyanate gas from the Bhopal accident was investigated using the mesoscale atmospheric dispersion modeling system. A series of numerical experiments were performed to investigate the possible role of the mesoscale circulations on this industrial gas episode. The temporal and spatial variations of the wind and turbulence fields were simulated with the mesoscale model. The dispersion characteristics of the accidental

  14. Mesoscale Backtracking by Means of Atmospheric Transport Modeling of Xenon Plumes Measured by Radionuclide Gas Stations

    NASA Astrophysics Data System (ADS)

    Armand, P. P.; Achim, P.; Taffary, T.

    2006-12-01

    The monitoring of atmospheric radioactive xenon concentration is performed for nuclear safety regulatory requirements. It is also planned to be used for the detection of hypothetical nuclear tests in the framework of the Comprehensive nuclear-Test-Ban Treaty (CTBT). In this context, the French Atomic Energy Commission designed a high sensitive and automated fieldable station, named SPALAX, to measure the activity concentrations of xenon isotopes in the atmosphere. SPALAX stations were set up in Western Europe and have been operated quite continuously for three years or more, detecting principally xenon-133 and more scarcely xenon-135, xenon-133m and xenon-131m. There are around 150 nuclear power plants in the European Union, research reactors, reprocessing plants, medical production and application facilities releasing radioactive xenon in normal or incidental operations. A numerical study was carried out aiming to explain the SPALAX measurements. The mesoscale Atmospheric Transport Modelling involves the MM5 suite (PSU- NCAR) to predict the wind fields on nested domains, and FLEXPART, a 3D Lagrangian particle dispersion code, used to simulate the backward transport of xenon plumes detected by the SPALAX. For every event of detection, at least one potential xenon source has a significant efficiency of emission. The identified likely sources are located quite close to the SPALAX stations (some tens of kilometres), or situated farther (a few hundreds of kilometres). A base line of some mBq per cubic meter in xenon-133 is generated by the nuclear power plants. Peaks of xenon-133 ranging from tens to hundreds of mBq per cubic meter originate from a radioisotope production facility. The calculated xenon source terms required to obtain the SPALAX measurements are discussed and seem consistent with realistic emissions from the xenon sources in Western Europe.

  15. The Impact of TRMM on Mesoscale Model Simulation of Super Typhoon Paka

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Jia, Y.; Halverson, J.; Hou, A.; Olson, W.; Rodgers, E.; Simpson, J.

    1999-01-01

    Tropical cyclone Paka formed during the first week of December 1997 and underwent three periods of rapid intensification over the following two weeks. During one of these periods, which initiated early on December 10, Paka's Dvorak-measured windspeed increased from 23 to 60 m/s over a 48-hr period. On December 18, during the last rapid deepening episode, Paka became a supertyphoon with a maximum wind speed of about 80 m/s. In this study, the Penn State/NCAR Mesoscale Model (MM5) with improved physics (i.e., cloud microphysics, radiation, land-soil-vegetation-surface processes, and TOGA COARE flux scheme) and a multiple level nesting technique (135, 45 and 15 km horizontal resolution) will be used to simulate supertyphoon Paka. We performed two runs initialized with Goddard Earth Observing System (GEOS) data sets. The first GEOS data set does not incorporate either TRMM (tropical rainfall measuring mission satellite) or SSM/I (sensor microwave imager) observed rainfall fields into the GEOS's assimilation system while the second one does. Preliminary results show that the MM5 simulated surface pressure deepened by more than 25 mb (45 km resolution domain) in the run initialized with the GEOS data set incorporating TRMM and SSM/I derived rainfall, compared to the one initialized without. However, the track and precipitation patterns are quite similar between the runs. In our presentation, we will show the impact of TRMM rainfall upon the MM5 simulation of Paka at various horizontal resolutions. We will also examine the physical processes associated with initial explosive development by comparing MM5 simulated rainfall and latent heat release. In addition, budget (vorticity, PV, momentum and heat) calculations and sensitivity tests will be performed to examine the upper-tropospheric and SST mechanisms responsible for the explosive development of Paka.

  16. Macroscale modeling and mesoscale observations of plasma density structures in the polar cap

    SciTech Connect

    Basu, S.; Basu, S.; Sojka, J.J.

    1995-04-15

    The seasonal and UT variation of mesoscale structures (10 km - 100 m) in the central polar cap has been obtained from an analysis of 250-MHz intensity scintillation observations made at Thule, Greenland. It has been established earlier that mesoscale structures causing scintillations of satellite signals may develop at the edges of macroscale structures (several hundred km) such as discrete polar cap plasma density enhancements or patches through the gradient drift instability process. As such, the authors examined the seasonal and UT variation of polar cap patches simulated by using the USU Time Dependent Ionospheric Model (TDIM) under conditions of southward B{sub z}. A fairly remarkable similarity is found between the scintillation observations and the model predictions of patch occurrence. For instance, both the patch and scintillation occurrences are minimized during the winter solstice (northern hemisphere) between 0800-1200 UT while also having their largest seasonal intensity between 2000-2400 UT. Little UT dependence of patches and scintillations is seen at equinox with high intensity being observed throughout the day, while during local summer the intensity of macroscale patches and mesoscale irregularities are found to be a minimum at all UT. These results indicate that macroscale features in the polar cap are routinely associated with plasma instabilities giving rise to smaller scale structures and that the specific patch formation mechanism assumed in the simulation is consistent with the observations. This ability to bridge between macroscale modeling and mesoscale observations provides a natural framework for the modeling of mesoscale structures themselves. This mesoscale modeling, in turn, can be utilized in a variety of radar and communication systems applications in the polar region. 25 refs., 3 figs.

  17. Assimilation of MGS Data Into a Coupled GCM-Mesoscale Model of the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Rafkin, Scot C. R.; Haberle, Robert (Technical Monitor)

    2001-01-01

    The project sought to develop a coupled GCM-mesoscale model and to assimilate Mars Global Surveyor (MGS) data into the coupled model. To achieve the project goals, four specific research activities were proposed. These activities are reiterated for completeness and the progress in each of the activities is noted in future sections of this report.

  18. A shallow convection parameterization for the non-hydrostatic MM5 mesoscale model

    SciTech Connect

    Seaman, N.L.; Kain, J.S.; Deng, A.

    1996-04-01

    A shallow convection parameterization suitable for the Pennsylvannia State University (PSU)/National Center for Atmospheric Research nonhydrostatic mesoscale model (MM5) is being developed at PSU. The parameterization is based on parcel perturbation theory developed in conjunction with a 1-D Mellor Yamada 1.5-order planetary boundary layer scheme and the Kain-Fritsch deep convection model.

  19. Nested-hierarchical scene models and image segmentation

    NASA Technical Reports Server (NTRS)

    Woodcock, C.; Harward, V. J.

    1992-01-01

    An improved model of scenes for image analysis purposes, a nested-hierarchical approach which explicitly acknowledges multiple scales of objects or categories of objects, is presented. A multiple-pass, region-based segmentation algorithm improves the segmentation of images from scenes better modeled as a nested hierarchy. A multiple-pass approach allows slow and careful growth of regions while interregion distances are below a global threshold. Past the global threshold, a minimum region size parameter forces development of regions in areas of high local variance. Maximum and viable region size parameters limit the development of undesirably large regions. Application of the segmentation algorithm for forest stand delineation in TM imagery yields regions corresponding to identifiable features in the landscape. The use of a local variance, adaptive-window texture channel in conjunction with spectral bands improves the ability to define regions corresponding to sparsely stocked forest stands which have high internal variance.

  20. The CAOS model: a physically based, flexible hydrological model for the mesoscale

    NASA Astrophysics Data System (ADS)

    Westhoff, Martijn; Zehe, Erwin

    2014-05-01

    Hydrological models are not only tools to predict discharge, but they are also hypotheses of how a catchment functions with respect to rainfall-runoff behaviour. In this work in progress, we present a new (physically based) model concept that should ultimately be suitable to run at the mesoscale. To be able to run it efficiently on the mesoscale, the model cannot be too complex. Yet, we wanted it physically based, with explicit incorporation of dissipative structures, such as macropores and lateral preferential flow paths. Besides water fluxes it should also be able to simulate solute concentrations and energy fluxes. This helps to parameterize the model while the model is also thermodynamically consistent, meaning that it is suitable to test thermodynamic optimality principles (such as maximum entropy production principle). With these constraints in mind, we developed a model where, in each subroutine, flow is modelled in only one dimension (vertical for the unsaturated zone and lateral for subsurface storm flow, groundwater flow and stream flow routines, making the model multiple 1-D), decreasing computation time significantly. The code is developed in an object oriented way, leading to more flexibility to test different model structures. For example, we will demonstrate the effect on simulated rapid subsurface flow for different mathematical descriptions (i.e. the Darcy-Weisbach equation vs. the diffusive wave and kinematic wave equation). For this study, the model will also be evaluated for hillslopes in three different geological settings within the Attert Basin in Luxembourg.

  1. Regional Model Nesting Within GFS Daily Forecasts Over West Africa

    NASA Technical Reports Server (NTRS)

    Druyan, Leonard M.; Fulakeza, Matthew; Lonergan, Patrick; Worrell, Ruben

    2010-01-01

    The study uses the RM3, the regional climate model at the Center for Climate Systems Research of Columbia University and the NASA/Goddard Institute for Space Studies (CCSR/GISS). The paper evaluates 30 48-hour RM3 weather forecasts over West Africa during September 2006 made on a 0.5 grid nested within 1 Global Forecast System (GFS) global forecasts. September 2006 was the Special Observing Period #3 of the African Monsoon Multidisciplinary Analysis (AMMA). Archived GFS initial conditions and lateral boundary conditions for the simulations from the US National Weather Service, National Oceanographic and Atmospheric Administration were interpolated four times daily. Results for precipitation forecasts are validated against Tropical Rainfall Measurement Mission (TRMM) satellite estimates and data from the Famine Early Warning System (FEWS), which includes rain gauge measurements, and forecasts of circulation are compared to reanalysis 2. Performance statistics for the precipitation forecasts include bias, root-mean-square errors and spatial correlation coefficients. The nested regional model forecasts are compared to GFS forecasts to gauge whether nesting provides additional realistic information. They are also compared to RM3 simulations driven by reanalysis 2, representing high potential skill forecasts, to gauge the sensitivity of results to lateral boundary conditions. Nested RM3/GFS forecasts generate excessive moisture advection toward West Africa, which in turn causes prodigious amounts of model precipitation. This problem is corrected by empirical adjustments in the preparation of lateral boundary conditions and initial conditions. The resulting modified simulations improve on the GFS precipitation forecasts, achieving time-space correlations with TRMM of 0.77 on the first day and 0.63 on the second day. One realtime RM3/GFS precipitation forecast made at and posted by the African Centre of Meteorological Application for Development (ACMAD) in Niamey, Niger

  2. Development of a 1D canopy module to couple mesoscale meteorogical model with building energy model

    NASA Astrophysics Data System (ADS)

    Mauree, Dasaraden; Kohler, Manon; Blond, Nadège; Clappier, Alain

    2013-04-01

    The actual global warming, highlighted by the scientific community, is due to the greenhouse gases emissions resulting from our energy consumption. This energy is mainly produced in cities (about 70% of the total energy use). Around 36% of this energy are used in buildings (residential/tertiary) and this accounts for about 20% of the greenhouse gases emissions. Moreover, the world population is more and more concentrated in urban areas, 50% of the actual world population already lives in cities and this ratio is expected to reach 70% by 2050. With the obviously increasing responsibility of cities in climate change in the future, it is of great importance to go toward more sustainable cities that would reduce the energy consumption in urban areas. The energy use inside buildings is driven by two factors: (1) the level of comfort wished by the inhabitants and (2) the urban climate. On the other hand, the urban climate is influenced by the presence of buildings. Indeed, artificial surfaces of urban areas modify the energy budget of the Earth's surface and furthermore, heat is released into the atmosphere due to the energy used by buildings. Modifications at the building scale (micro-scale) can thus have an influence on the climate of the urban areas and surroundings (meso-scale), and vice and versa. During the last decades, meso-scale models have been developed to simulate the atmospheric conditions for domain of 100-1000km wide with a resolution of few kilometers. Due to their low resolution, the effects of small obstacles (such as buildings, trees, ...) near the ground are not reproduced properly and parameterizations have been developed to represent such effects in meso-scale models. On the other side, micro-scale models have a higher resolution (around 1 meter) and consequently can better simulate the impact of obstacles on the atmospheric heat flux exchanges with the earth surface. However, only a smaller domain (less than 1km) can be simulated for the same

  3. Detection of mesoscale zones of atmospheric instabilities using remote sensing and weather forecasting model data

    NASA Astrophysics Data System (ADS)

    Winnicki, I.; Jasinski, J.; Kroszczynski, K.; Pietrek, S.

    2009-04-01

    The paper presents elements of research conducted in the Faculty of Civil Engineering and Geodesy of the Military University of Technology, Warsaw, Poland, concerning application of mesoscale models and remote sensing data to determining meteorological conditions of aircraft flight directly related with atmospheric instabilities. The quality of meteorological support of aviation depends on prompt and effective forecasting of weather conditions changes. The paper presents a computer module for detecting and monitoring zones of cloud cover, precipitation and turbulence along the aircraft flight route. It consists of programs and scripts for managing, processing and visualizing meteorological and remote sensing databases. The application was developed in Matlab® for Windows®. The module uses products of COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System) mesoscale non-hydrostatic model of the atmosphere developed by the US Naval Research Laboratory, satellite images acquisition system from the MSG-2 (Meteosat Second Generation) of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and meteorological radars data acquired from the Institute of Meteorology and Water Management (IMGW), Warsaw, Poland. The satellite images acquisition system and the COAMPS model are run operationally in the Faculty of Civil Engineering and Geodesy. The mesoscale model is run on an IA64 Feniks multiprocessor 64-bit computer cluster. The basic task of the module is to enable a complex analysis of data sets of miscellaneous information structure and to verify COAMPS results using satellite and radar data. The research is conducted using uniform cartographic projection of all elements of the database. Satellite and radar images are transformed into the Lambert Conformal projection of COAMPS. This facilitates simultaneous interpretation and supports decision making process for safe execution of flights. Forecasts are based on horizontal

  4. Propagation of Impact-Induced Shock Waves in Heterogenous Rocks Using Mesoscale Modeling

    NASA Astrophysics Data System (ADS)

    Güldemeister, N.; Durr, N.; Wünnemann, K.; Elbeshausen, D.; Hiermaier, S.

    2011-03-01

    In the framework of the “MEMIN” project, the effect of porosity in dry and water-saturated sandstone on shock wave loading is investigated. We conducted a series of numerical experiments of shock wave propagation in porous material using macro- as well as mesoscale models.

  5. Evaluation of a Mesoscale Atmospheric Dispersion Modeling System with Observations from the 1980 Great Plains Mesoscale Tracer Field Experiment. Part II: Dispersion Simulations.

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.; Piekle, Roger A.

    1996-03-01

    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 (MLPDM), has been used to simulate the emission, transport, and diffusion of a perfluorocarbon tracer-gas cloud for one afternoon surface release during the July 1980 Great Plains mesoscale tracer field experiment. The MLPDM was run for a baseline simulation and seven sensitivity experiments. The baseline simulation showed considerable skill in predicting such quantitative whole-could characteristics as peak ground-level concentration (GLC), maximum cloud width, cloud arrival and transit times, and crosswind integrated exposure at downwind distances of both 100 and 60 km. The baseline simulation also compared very favorably to simulations made by seven other MAD models for this same case in an earlier study. The sensitivity experiments explored the impact of various factors on MAD, especially the diurnal heating cycle and physiographic and atmospheric inhomogeneities, by including or excluding them in different combinations. The GLC `footprints' predicted in the sensitivity experiments were sensitive to differences in the simulated meteorological fields.The observations and the numerical simulations both suggest that the Great Plains nocturnal low-level jet played an important role in transporting and deforming the perfluorocarbon tracer cloud during this MAD experiment: the mean transport speed was supergeostrophic and both crosswind and alongwind cloud spreads were larger than can be explained by turbulent diffusion alone. The contributions of differential horizontal advection and mesoscale deformation to MAD dominate those of small-scale turbulent diffusion for this case, and Pasquill's delayed-shear enhancement mechanism for horizontal diffusion appears to have played a significant role during nighttime transport. These results demonstrate the

  6. Evaluation of a mesoscale atmospheric dispersion modeling system with observations from the 1980 Great Plains mesoscale tracer field experiment. Part I: Datasets and meterological simulations

    SciTech Connect

    Moran, M.D.; Pielke, R.A.

    1996-03-01

    A mesoscale atmospheric dispersion (MAD) numerical modeling system, consisting of a mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model, was used to simulate transport and diffusion of a perfluorocarbon tracer-gas cloud for a surface release during the July 1980 Great Plains mesoscale tracer field experiment. Ground-level concentration (GLC) measurements taken downwind of the release site up to three days after the tracer release were available for comparison. Quantitative measures of significant dispersion characteristics obtained from analysis of the tracer cloud`s moving GLC {open_quotes}footprint{close_quotes} were used to evaluate the simulation of the MAD case. MAD is more dependent on the spatial and temporal structure of the transport wind field than is short-range atmospheric dispersion. For the tracer experiment, the observations suggest that the nocturnal low-level jet played an important role in transporting and deforming the tracer cloud. Ten two- and three-dimensional numerical meteorological experiments were devised to investigate the relative contributions of topography, other surface inhomogeneities, atmospheric baroclinicity, synoptic-scale flow evolution, and meteorological model initialization time to the structure and evolution of the low-level mesoscale flow field and thus to MAD. Results from the meteorological simulations are compared in this paper. The predicted wind fields display significant differences, which give rise in turn to significant differences in predicted low-level transport. The presence of an oscillatory ageostrophic component in the observed synoptic low-level winds for this case is shown to complicate initialization of the meteorological model considerably and is the likely cause of directional errors in the predicted mean tracer transport. A companion paper describes the results from the associated dispersion simulations. 76 refs., 13 figs., 6 tabs.

  7. A nested multisite daily rainfall stochastic generation model

    NASA Astrophysics Data System (ADS)

    Srikanthan, Ratnasingham; Pegram, Geoffrey G. S.

    2009-06-01

    SummaryThis paper describes a nested multisite daily rainfall generation model which preserves the statistics at daily, monthly and annual levels of aggregation. A multisite two-part daily model is nested in multisite monthly, then annual models. A multivariate set of fourth order Markov chains is used to model the daily occurrence of rainfall; the daily spatial correlation in the occurrence process is handled by using suitably correlated uniformly distributed variates via a Normal Scores Transform (NST) obtained from a set of matched multinormal pseudo-random variates, following Wilks [Wilks, D.S., 1998. Multisite generalisation of a daily stochastic precipitation generation model. Journal of Hydrology 210, 178-191]; we call it a hidden covariance model. A spatially correlated two parameter gamma distribution is used to obtain the rainfall depths; these values are also correlated via a specially matched hidden multinormal process. For nesting, the generated daily rainfall sequences at all the sites are aggregated to monthly rainfall values and these values are modified by a set of lag-1 autoregressive multisite monthly rainfall models. The modified monthly rainfall values are aggregated to annual rainfall and these are then modified by a lag-1 autoregressive multisite annual model. This nesting process ensures that the daily, monthly and annual means and covariances are preserved. The model was applied to a region with 30 rainfall sites, one of the five sets reported by Srikanthan [Srikanthan, R., 2005. Stochastic Generation of Daily Rainfall Data at a Number of Sites. Technical Report 05/7, CRC for Catchment Hydrology. Monash University, 66p]. A comparison of the historical and generated statistics shows that the model preserves all the important characteristics of rainfall at the daily, monthly and annual time scales, including the spatial structure. There are some outstanding features that need to be improved: depths of rainfall on isolated wet days and

  8. Impact of Submesoscale Eddies on Synoptic and Mesoscale Oceanic Structures in a Continental Shelf Margin Analyzed with a Downscaling Ocean Model of Japan Sea

    NASA Astrophysics Data System (ADS)

    Miyazaki, D.; Uchiyama, Y.; Kanki, R.; Miyazawa, Y.

    2014-12-01

    Japan Sea (JPS) is connected to other seas by five narrow and shallow straits with a minimal depth of the order of 100 meters or less, resulting in limited water exchange thereby isolating the water and aquatic ecosystem. The modeling and observational studies on quantifying the dynamics of JPS are still undergoing (e.g., Hirose et al., 2007), whereas effects of submesoscale dynamics on the mean structure, eddies, and material dispersal in JPS have not been extensively investigated yet. In the present study, we conduct a detailed oceanic downscaling numerical experiment using ROMS in a double nested configuration bounded on the assimilative JCOPE2 (Miyazawa et al., 2009) reanalysis at horizontal resolutions of 3 km (ROMS-L1) and 1 km (ROMS-L2). The L1 and L2 models are compared to the observed data to show a good agreement with an appropriate parameter choice. Our models sufficiently reproduce the overall frontal structure and associated major currents in JPS consisting of the Liman Cold Current along the Russian coast and the Tsushima Warm Current along the Japanese coast. Surface normalized relative vorticity fields demonstrate that both the mesoscale and submesoscale eddies are apparently enhanced, as the model grid resolution is finer. In summer and fall, mesoscale eddies are evident in L1 and L2. In contrast in winter and spring, submesoscale eddies are significantly energized in the whole JPS particularly in L2 due to the surface cooling that preconditions symmetric instability (e.g., Thomas et al., 2012). The enhancement of EKE appears around Tsushima strait and along the Korean Peninsula in L1, while EKE in L2 is extensively increased in the most part of the southern JPS. On the other hand, a SSH variance, a proxy of mesoscale variability, is more realistically distributed in L2 than L1, suggesting a potential importance of submesoscale eddies on the mesoscale dynamics.

  9. High-Resolution Specification of the Land and Ocean Surface for Improving Regional Mesoscale Model Predictions

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; Lazarus, Steven M.; Splitt, Michael E.; Crosson, William L.; Lapenta, William M.; Jedlovec, Gary J.; Peters-Lidard, Christa D.

    2008-01-01

    The exchange of energy and moisture between the Earth's surface and the atmospheric boundary layer plays a critical role in many meteorological processes. High-resolution, accurate representations of surface properties such as sea-surface temperature (SST), soil temperature and moisture content, ground fluxes, and vegetation are necessary to better understand the Earth-atmosphere interactions and improve numerical predictions of sensible weather. The NASA Short-term Prediction Research and Transition (SPoRT) Center has been conducting separate studies to examine the impacts of high-resolution land-surface initialization data from the Goddard Space Flight Center Land Information System (LIS) on subsequent WRF forecasts, as well as the influence of initializing WRF with SST composites derived from the MODIS instrument. This current project addresses the combined impacts of using high-resolution lower boundary data over both land (LIS data) and water (MODIS SSTs) on the subsequent daily WRF forecasts over Florida during May 2004. For this experiment, the WRF model is configured to run on a nested domain with 9- km and 3-kin grid spacing, centered on the Florida peninsula and adjacent coastal waters of the Gulf of Mexico and Atlantic Ocean. A control configuration of WRF is established to take all initial condition data from the NCEP Eta model. Meanwhile, two WRF experimental runs are configured to use high-resolution initialization data from (1) LIS land-surface data only, and (2) a combination of LIS data and high-resolution MODIS SST composites. The experiment involves running 24-hour simulations of the control WRF configuration, the MS-initialized WRF, and the LIS+MODIS-initialized WRF daily for the entire month of May 2004. All atmospheric data for initial and boundary conditions for the Control, LIS, and LIS+MODIS runs come from the NCEP Eta model on a 40-km grid. Verification statistics are generated at land surface observation sites and buoys, and the impacts

  10. Simultaneous Nested Modeling from the Synoptic Scale to the LES Scale

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Wu, W.; Gregory, G.; Warner, T.; Swerdlin, S.

    2009-04-01

    Many applications require accurate weather information over broad temporal and spatial scales. For example, wind energy prediction requires regional weather forecasting to cope with intra-hour, multi-hour and day ahead decision-making. In addition, microscale modeling is needed to support wind turbine sitting decisions and turbine operations. In the last 10 years, the National Center for Atmospheric Research, US, has developed a Real-Time Four-Dimensional Data Assimilation (RTFDDA) and forecasting system to support diverse weather-critical applications such as wind energy forecasting. RTFDDA, built upon the Weather Research and Forecasting (WRF) model, is a rapid-cycling, multi-scale weather system with a capability for effectively combining all available weather observations with the full-physics WRF model to produce high-accuracy multi-scale 4D weather information from synoptic scales (~2000 km), to mesoscales (2 - 2000 km), and to microscales (< 2 km). RTFDDA performs successive downscaling from synoptic numerical weather predictions (based on global models), to regional weather predictions (mesoscale weather processes), and to small and microscale weather modeling with Large Eddy Simulation (LES). Two real weather cases with typical strong local forcing phenomena, one with an isolated elongated bell-shaped mountain in central Utah and the other with complex coastlines along the Chesapeake Bay, Maryland, were simulated using the WRF-RTFDDA-LES system with six nested domains having grid sizes of 30, 10, 3.333, 1.111, 0.369 and 0.123 km. The NASA SRTM (Shuttle Radar-sensing Topography Mission) 30-m resolution terrain heights were used to specify the fine mesh model terrain and to adjust fine-scale coastlines. Both cases were run for 24+ hours to span the diurnal evolution of local weather. Analysis of the model results indicates an encouraging downscaling capability of the modeling system in simulating the high-resolution underlying forcing and interaction with

  11. ROCKY MOUNTAIN ACID DEPOSITION MODEL ASSESSMENT: EVALUATION OF MESOSCALE ACID DEPOSITION MODELS FOR USE IN COMPLEX TERRAIN

    EPA Science Inventory

    The report includes an evaluation of candidate meteorological models and acid deposition models. The hybrid acid deposition/air quality modeling system for the Rocky Mountains makes use of a mesoscale meteorological model, which includes a new diagnostic wind model, as a driver f...

  12. A cumulus parameterization scheme designed for nested grid meso-{beta} scale models

    SciTech Connect

    Weissbluth, M.J.; Cotton, W.R.

    1991-12-31

    A generalized cumulus parameterization based upon higher order turbulence closure has been incorporated into one dimensional simulations. The scheme consists of a level 2.5w turbulence closure scheme mated with a convective adjustment scheme. The convective adjustment scheme includes a gradient term which can be interpreted as either a subsidence term when the scheme is used in large scale models or a mesoscale compensation term when the scheme is used in mesoscale models. The scheme also includes a convective adjustment term which is interpreted as a detrainment term in large scale models. In mesoscale models, the mesoscale compensation term and the advection by the mean vertical motions combine to yield no net advection which is desirable since the convective moistening and heating is now wholly accomplished by the convective adjustment term; double counting is then explicitly eliminated. One dimensional simulations indicate satisfactory performance of the cumulus parameterization scheme for a non-entraining updraft.

  13. A cumulus parameterization scheme designed for nested grid meso-. beta. scale models

    SciTech Connect

    Weissbluth, M.J.; Cotton, W.R.

    1991-01-01

    A generalized cumulus parameterization based upon higher order turbulence closure has been incorporated into one dimensional simulations. The scheme consists of a level 2.5w turbulence closure scheme mated with a convective adjustment scheme. The convective adjustment scheme includes a gradient term which can be interpreted as either a subsidence term when the scheme is used in large scale models or a mesoscale compensation term when the scheme is used in mesoscale models. The scheme also includes a convective adjustment term which is interpreted as a detrainment term in large scale models. In mesoscale models, the mesoscale compensation term and the advection by the mean vertical motions combine to yield no net advection which is desirable since the convective moistening and heating is now wholly accomplished by the convective adjustment term; double counting is then explicitly eliminated. One dimensional simulations indicate satisfactory performance of the cumulus parameterization scheme for a non-entraining updraft.

  14. Procedures for offline grid nesting in regional ocean models

    NASA Astrophysics Data System (ADS)

    Mason, Evan; Molemaker, Jeroen; Shchepetkin, Alexander F.; Colas, Francois; McWilliams, James C.; Sangrà, Pablo

    One-way offline nesting of a primitive-equation regional ocean numerical model (ROMS) is investigated, with special attention to the boundary forcing file creation process. The model has a modified open boundary condition which minimises false wave reflections, and is optimised to utilise high-frequency boundary updates. The model configuration features a previously computed solution which supplies boundary forcing data to an interior domain with an increased grid resolution. At the open boundaries of the interior grid (the child) the topography is matched to that of the outer grid (the parent), over a narrow transition region. A correction is applied to the normal baroclinic and barotropic velocities at the open boundaries of the child to ensure volume conservation. It is shown that these steps, together with a carefully constructed interpolation of the parent data, lead to a high-quality child solution, with minimal artifacts such as persistent rim currents and wave reflections at the boundaries. Sensitivity experiments provide information about the robustness of the model open boundary condition to perturbations in the surface wind stress forcing field, to the perturbation of the volume conservation enforcement in the boundary forcing, and to perturbation of the vertical density structure in the boundary forcing. This knowledge is important when extending the nesting technique to include external data from alien sources, such as ocean models with physics and/or numerics different from ROMS, or from observed climatologies of temperature, salinity and sea level.

  15. Modified finite-element model for application to terrain-induced mesoscale flows

    SciTech Connect

    Lee, R.L.; Leone, J.M. Jr.; Gresho, P.M.

    1982-11-01

    Terrain-induced mesoscale flows are localized atmospheric motions generated primarily by surface inhomogeneities such as differential heating and irregular terrain. Well-known examples of such flows are sea-and-land breeze circulations, mountain-valley flows, urban heat island circulations and mountain lee waves. A numerical model capable of capturing the details of these frequently complicated flow patterns must often contain a realistic and rather accurate representation of the relevant terrain. Over the last decade, mesoscale models have been developed in which various approaches were used to incorporate variable terrain. In this study, a somewhat unique approach, based on a modified finite element procedure, was used to solve the nonhydrostatic planetary boundary layer equations. The nonhydrostatic and finite element features of the model are particularly advantageous for modeling flows over complex topography. The numerical aspects of the model, the parameterizations currently used, and a few preliminary results are presented.

  16. Urban morphological analysis for mesoscale meteorological and dispersion modeling applications : current issues

    SciTech Connect

    Burian, S. J.; Brown, M. J.; Ching, J.; Cheuk, M. L.; Yuan, M.; McKinnon, A. T.; Han, W. S.

    2004-01-01

    Accurate predictions of air quality and atmospheric dispersion at high spatial resolution rely on high fidelity predictions of mesoscale meteorological fields that govern transport and turbulence in urban areas. However, mesoscale meteorological models do not have the spatial resolution to directly simulate the fluid dynamics and thermodynamics in and around buildings and other urban structures that have been shown to modify micro- and mesoscale flow fields (e.g., see review by Bornstein 1987). Mesoscale models therefore have been adapted using numerous approaches to incorporate urban effects into the simulations (e.g., see reviews by Brown 2000 and Bornstein and Craig 2002). One approach is to introduce urban canopy parameterizations to approximate the drag, turbulence production, heating, and radiation attenuation induced by sub-grid scale buildings and urban surface covers (Brown 2000). Preliminary results of mesoscale meteorological and air quality simulations for Houston (Dupont et al. 2004) demonstrated the importance of introducing urban canopy parameterizations to produce results with high spatial resolution that accentuates variability, highlights important differences, and identifies critical areas. Although urban canopy parameterizations may not be applicable to all meteorological and dispersion models, they have been successfully introduced and demonstrated in many of the current operational and research mode mesoscale models, e.g., COAMPS (Holt et al. 2002), HOTMAC (Brown and Williams 1998), MM5 (e.g., Otte and Lacser 2001; Lacser and Otte 2002; Dupont et al. 2004), and RAMS (Rozoff et al. 2003). The primary consequence of implementing an urban parameterization in a mesoscale meteorological model is the need to characterize the urban terrain in greater detail. In general, urban terrain characterization for mesoscale modeling may be described as the process of collecting datasets of urban surface cover physical properties (e.g., albedo, emissivity) and

  17. Mesoscale modelling of water vapour in the tropical UTLS: two case studies from the HIBISCUS campaign

    NASA Astrophysics Data System (ADS)

    Marécal, V.; Durry, G.; Longo, K.; Freitas, S.; Rivière, E. D.; Pirre, M.

    2007-03-01

    In this study, we evaluate the ability of the BRAMS (Brazilian Regional Atmospheric Modeling System) mesoscale model compared to ECMWF global analysis to simulate the observed vertical variations of water vapour in the tropical upper troposphere and lower stratosphere (UTLS). The observations are balloon-borne measurements of water vapour mixing ratio and temperature from micro-SDLA (Tunable Diode Laser Spectrometer) instrument. Data from two balloon flights performed during the 2004 HIBISCUS field campaign are used to compare with the mesoscale simulations and to the ECMWF analysis. The observations exhibit fine scale vertical structures of water vapour of a few hundred meters height. The ECMWF vertical resolution (~1 km) is too coarse to capture these vertical structures in the UTLS. With a vertical resolution similar to ECMWF, the mesoscale model performs better than ECMWF analysis for water vapour in the upper troposphere and similarly or slightly worse for temperature. The BRAMS model with 250 m vertical resolution is able to capture more of the observed fine scale vertical variations of water vapour compared to runs with a coarser vertical resolution. This is mainly related to: (i) the enhanced vertical resolution in the UTLS and (ii) to the more detailed microphysical parameterization providing ice supersaturations as in the observations. In near saturated or supersaturated layers, the mesoscale model predicted relative humidity with respect to ice saturation is close to observations provided that the temperature profile is realistic. For temperature, the ECMWF analysis gives good results partly attributed to data assimilation. The analysis of the mesoscale model results showed that the vertical variations of the water vapour profile depends on the dynamics in unsaturated layer while the microphysical processes play a major role in saturated/supersaturated layers. In the lower stratosphere, the ECMWF model and the BRAMS model give very similar water vapour

  18. The effects of elevation data representation on mesoscale atmospheric model simulations

    SciTech Connect

    Walker, H.; Leone, J.M. Jr.; Kim, Jinwon

    1996-01-01

    Mesoscale atmospheric model simulations rely on descriptions of the land surface characteristics, which must be developed from geographic databases. Certain features of the geographic data, such as its resolution and accuracy, as well as the method of processing for use in the model, can be very important in producing accurate model simulations. The work described here is part of research effort into the relationship between these aspects of geographic data and the performance of mesoscale atmospheric models and is particularly focused on elevation data and how it is prepared for use in such models. A source for digital elevation data will typically not be at the resolution required for a given model simulation and so a resampling step is required. In addition, predictive non-linear model often cannot accept forcing at high spatial frequencies due to the terrain, thus smoothing is also required. The effect of different means of resampling and smoothing elevation data on two types of model simulations is investigated. At smaller spatial scales, nocturnal drainage winds in mountain valleys in Colorado are examined for effects on the general characteristics as well as the details of the flows. At the larger end of the mesoscale, extended simulations of California weather are examined for effects on orographic lifting, low-level convergence and divergence and ultimately rain and snow distribution.

  19. Coupling a Mesoscale Numerical Weather Prediction Model with Large-Eddy Simulation for Realistic Wind Plant Aerodynamics Simulations (Poster)

    SciTech Connect

    Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.

    2014-06-01

    Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.

  20. A four-dimensional, mesoscale, non-gaussian multispectral smoke model. Phase 1: Feasibility study

    NASA Astrophysics Data System (ADS)

    Yamartino, R. J.; Strimaitis, D. G.; Scire, J. S.; Insley, E. M.

    1992-12-01

    The feasibility of developing a four-dimensional, non-Gaussian mesoscale multispectral smoke model that could run on a personal computer is investigated. Several of the model components are formulated, coded, and tested. This included the main driver program for accessing and interpolating the mesoscale winds and generating particle trajectories, a sub-grid-scale velocity field generator based on the kinematic simulation approach, and a dry deposition model for particle deposition velocities. Current understanding of flow and turbulence modeling is reviewed and can be applied to developing appropriate kinematic simulation fields. Technical approaches to account for the height and particle size dependent probability of particle removal and to compute the point and path average particle concentrations are also presented. Conclusions and recommendations for future work are included.

  1. Ellipsoidal nested sampling, expression of the model uncertainty and measurement

    NASA Astrophysics Data System (ADS)

    Palmisano, C.; Mana, G.; Gervino, G.

    2015-07-01

    The measurand value, the conclusions, and the decisions inferred from measurements may depend on the models used to explain and to analyze the results. In this paper, the problems of identifying the most appropriate model and of assessing the model contribution to the uncertainty are formulated and solved in terms of Bayesian model selection and model averaging. As computational cost of this approach increases with the dimensionality of the problem, a numerical strategy, based on multimodal ellipsoidal nested sampling, to integrate over the nuisance parameters and to compute the measurand post-data distribution is outlined. In order to illustrate the numerical strategy, by use of MATHEMATICA an elementary example concerning a bimodal, two-dimensional distribution has also been studied.

  2. Studying PMMA films on silica surfaces with generic microscopic and mesoscale models

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Mukherji, D.; Daoulas, K. Ch.

    2016-07-01

    Polymer films on solid substrates present significant interest for fundamental polymer physics and industrial applications. For their mesoscale study, we develop a hybrid particle-based representation where polymers are modeled as worm-like chains and non-bonded interactions are introduced through a simple density functional. The mesoscale description is parameterized to match a generic microscopic model, which nevertheless can represent real materials. Choosing poly (methyl methacrylate) adsorbed on silica as a case study, the consistency of both models in describing conformational and structural properties in polymer films is investigated. We compare selected quantifiers of chain-shape, the structure of the adsorbed layer, as well as the statistics of loops, tails, and trains. Overall, the models are found to be consistent with each other. Some deviations in conformations and structure of adsorbed layer can be attributed to the simplified description of polymer/surface interactions and local liquid packing in the mesoscale model. These results are encouraging for a future development of pseudo-dynamical schemes, parameterizing the kinetics in the hybrid model via the dynamics of the generic microscopic model.

  3. MESO-SCALE MODELING OF THE INFLUENCE OF INTERGRANULAR GAS BUBBLES ON EFFECTIVE THERMAL CONDUCTIVITY

    SciTech Connect

    Paul C. Millett; Michael Tonks

    2011-06-01

    Using a mesoscale modeling approach, we have investigated how intergranular fission gas bubbles, as observed in high-burnup nuclear fuel, modify the effective thermal conductivity in a polycrystalline material. The calculations reveal that intergranular porosity has a significantly higher resistance to heat transfer compared to randomly-distributed porosity. A model is developed to describe this conductivity reduction that considers an effective grain boundary Kapitza resistance as a function of the fractional coverage of grain boundaries by bubbles.

  4. A Distributed Hydrological model Forced by DIMP2 Data and the WRF Mesoscale model

    NASA Astrophysics Data System (ADS)

    Wayand, N. E.

    2010-12-01

    Forecasted warming over the next century will drastically reduce seasonal snowpack that provides 40% of the world’s drinking water. With increased climate warming, droughts may occur more frequently, which will increase society’s reliance on this same summer snowpack as a water supply. This study aims to reduce driving data errors that lead to poor simulations of snow ablation and accumulation, and streamflow. Results from the Distributed Hydrological Model Intercomparison Project Phase 2 (DMIP2) project using the Distributed Hydrology Soil and Vegetation Model (DHSVM) highlighted the critical need for accurate driving data that distributed models require. Currently, the meteorological driving data for distributed hydrological models commonly rely on interpolation techniques between a network of observational stations, as well as historical monthly means. This method is limited by two significant issues: snowpack is stored at high elevations, where interpolation techniques perform poorly due to sparse observations, and historic climatological means may be unsuitable in a changing climate. Mesoscale models may provide a physically-based approach to supplement surface observations over high-elevation terrain. Initial results have shown that while temperature lapse rates are well represented by multiple mesoscale models, significant precipitation biases are dependent on the particular model microphysics. We evaluate multiple methods of downscaling surface variables from the Weather and Research Forecasting (WRF) model that are then used to drive DHSVM over the North Fork American River basin in California. A comparison between each downscaled driving data set and paired DHSVM results to observations will determine how much improvement in simulated streamflow and snowpack are gained at the expense of each additional degree of downscaling. Our results from DMIP2 will be used as a benchmark for the best available DHSVM run using all available observational data. The

  5. A process proof test for model concepts: Modelling the meso-scale

    NASA Astrophysics Data System (ADS)

    Hellebrand, Hugo; Müller, Christoph; Matgen, Patrick; Fenicia, Fabrizio; Savenije, Huub

    In hydrological modelling the use of detailed soil data is sometimes troublesome, since often these data are hard to obtain and, if available at all, difficult to interpret and process in a way that makes them meaningful for the model at hand. Intuitively the understanding and mapping of dominant runoff processes in the soil show high potential for improving hydrological models. In this study a labour-intensive methodology to assess dominant runoff processes is simplified in such a way that detailed soil maps are no longer needed. Nonetheless, there is an ongoing debate on how to integrate this type of information in hydrological models. In this study, dominant runoff processes (DRP) are mapped for meso-scale basins using the permeability of the substratum, land use information and the slope in a GIS. During a field campaign the processes are validated and for each DRP assumptions are made concerning their water storage capacity. The latter is done by means of combining soil data obtained during the field campaign with soil data obtained from the literature. Second, several parsimoniously parameterized conceptual hydrological models are used that incorporate certain aspects of the DRP. The result of these models are compared with a benchmark model in which the soil is represented as only one lumped parameter to test the contribution of the DRP in hydrological models. The proposed methodology is tested for 15 meso-scale river basins located in Luxembourg. The main goal of this study is to investigate if integrating dominant runoff processes, which have high information content concerning soil characteristics, with hydrological models allows the improvement of simulation results models with a view to regionalization and predictions in ungauged basins. The regionalization procedure gave no clear results. The calibration procedure and the well-mixed discharge signal of the calibration basins are considered major causes for this and it made the deconvolution of

  6. Local Bathymetry Estimation Using Variational Inverse Modeling: A Nested Approach

    NASA Astrophysics Data System (ADS)

    Almeida, T. G.; Walker, D. T.; Farquharson, G.

    2014-12-01

    Estimation of subreach river bathymetry from remotely-sensed surface velocity data is presented using variational inverse modeling applied to the 2D depth-averaged, shallow-water equations (SWEs). A nested approach is adopted to focus on obtaining an accurate estimate of bathymetry over a small region of interest within a larger complex hydrodynamic system. This approach reduces computational cost significantly. We begin by constructing a minimization problem with a cost function defined by the error between observed and estimated surface velocities, and then apply the SWEs as a constraint on the velocity field. An adjoint SWE model is developed through the use of Lagrange multipliers, converting the unconstrained minimization problem into a constrained one. The adjoint model solution is used to calculate the gradient of the cost function with respect to bathymetry. The gradient is used in a descent algorithm to determine the bathymetry that yields a surface velocity field that is a best-fit to the observational data. In this application of the algorithm, the 2D depth-averaged flow is computed within a nested framework using Delft3D-FLOW as the forward computational model. First, an outer simulation is generated using discharge rate and other measurements from USGS and NOAA, assuming a uniform bottom-friction coefficient. Then a nested, higher resolution inner model is constructed using open boundary condition data interpolated from the outer model (see figure). Riemann boundary conditions with specified tangential velocities are utilized to ensure a near seamless transition between outer and inner model results. The initial guess bathymetry matches the outer model bathymetry, and the iterative assimilation procedure is used to adjust the bathymetry only for the inner model. The observation data was collected during the ONR Rivet II field exercise for the mouth of the Columbia River near Hammond, OR. A dual beam squinted along-track-interferometric, synthetic

  7. Evaluation of a mesoscale atmospheric dispersion modeling system with observations from the 1980 Great Plains mesoscale tracer field experiment. Part II: Dispersion simulations

    SciTech Connect

    Moran, M.D.; Pielke, R.A.

    1996-03-01

    A mesoscale atmospheric dispersion (MAD) numerical modeling system, consisting of a mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model (MLPDM), was used to simulate the emission, transport, and diffusion of a perfluorocarbon tracer-gas cloud for a surface release during a tracer field experiment. The MLPDM was run for a baseline simulation and seven sensitivity experiments. The baseline simulation showed considerable skill in predicting peak ground-level concentration (GLC), maximum cloud width, cloud arrival and transit times, and crosswind integrated exposure at downwind distances of 100 and 600 km. The baseline simulation also compared very well to simulations made by seven other MAD models for the same case in an earlier study. The sensitivity experiments explored the impact of various factors on MAD, especially the diurnal heating cycle and physiographic and atmospheric inhomogeneities, by including or excluding them in different combinations. The GLC footprints predicted in sensitivity experiments were sensitive to differences in simulated meteorological fields. The observations and numerical simulations suggest that the nocturnal low-level jet played an important role in transporting and deforming the tracer cloud during this MAD experiment: the mean transport speed was supergeostrophic and both crosswind and alongwind cloud spreads were larger than can be explained by turbulent diffusion alone. The contributions of differential horizontal advection and mesoscale deformation to MAD dominate those of small-scale turbulent diffusion for this case, and Pasquill`s delayed-shear enhancement mechanism for horizontal diffusion appears to have played a significant role during nighttime transport. These results demonstrate the need in some flow regimes for better temporal resolution of boundary layer vertical shear in MAD models than is available from the conventional twice-daily rawinsonde network. 34 refs., 14 figs., 4 tabs.

  8. An Adaptive Sequential Design for Model Discrimination and Parameter Estimation in Non-Linear Nested Models

    SciTech Connect

    Tommasi, C.; May, C.

    2010-09-30

    The DKL-optimality criterion has been recently proposed for the dual problem of model discrimination and parameter estimation, for the case of two rival models. A sequential version of the DKL-optimality criterion is herein proposed in order to discriminate and efficiently estimate more than two nested non-linear models. Our sequential method is inspired by the procedure of Biswas and Chaudhuri (2002), which is however useful only in the set up of nested linear models.

  9. Model studies on the role of moist convection as a mechanism for interaction between the mesoscales

    NASA Technical Reports Server (NTRS)

    Waight, Kenneth T., III; Song, J. Aaron; Zack, John W.; Price, Pamela E.

    1991-01-01

    A three year research effort is described which had as its goal the development of techniques to improve the numerical prediction of cumulus convection on the meso-beta and meso-gamma scales. Two MESO models are used, the MASS (mesoscale) and TASS (cloud scale) models. The primary meteorological situation studied is the 28-29 Jun. 1986 Cooperative Huntsville Meteorological Experiment (COHMEX) study area on a day with relatively weak large scale forcing. The problem of determining where and when convection should be initiated is considered to be a major problem of current approaches. Assimilation of moisture data from satellite, radar, and surface data is shown to significantly improve mesoscale simulations. The TASS model is shown to reproduce some observed mesoscale features when initialized with 3-D observational data. Convection evolution studies center on comparison of the Kuo and Fritsch-Chappell cumulus parameterization schemes to each other, and to cloud model results. The Fritsch-Chappell scheme is found to be superior at about 30 km resolution, while the Kuo scheme does surprisingly well in simulating convection down to 10 km in cases where convergence features are well-resolved by the model grid. Results from MASS-TASS interaction experiments are presented and discussed. A discussion of the future of convective simulation is given, with the conclusion that significant progress is possible on several fronts in the next few years.

  10. THE APPLICATION OF AN EVOLUTIONARY ALGORITHM TO THE OPTIMIZATION OF A MESOSCALE METEOROLOGICAL MODEL

    SciTech Connect

    Werth, D.; O'Steen, L.

    2008-02-11

    We show that a simple evolutionary algorithm can optimize a set of mesoscale atmospheric model parameters with respect to agreement between the mesoscale simulation and a limited set of synthetic observations. This is illustrated using the Regional Atmospheric Modeling System (RAMS). A set of 23 RAMS parameters is optimized by minimizing a cost function based on the root mean square (rms) error between the RAMS simulation and synthetic data (observations derived from a separate RAMS simulation). We find that the optimization can be efficient with relatively modest computer resources, thus operational implementation is possible. The optimization efficiency, however, is found to depend strongly on the procedure used to perturb the 'child' parameters relative to their 'parents' within the evolutionary algorithm. In addition, the meteorological variables included in the rms error and their weighting are found to be an important factor with respect to finding the global optimum.

  11. Hot-spot contributions in shocked high explosives from mesoscale ignition models

    NASA Astrophysics Data System (ADS)

    Levesque, G.; Vitello, P.; Howard, W. M.

    2013-06-01

    High explosive performance and sensitivity is strongly related to the mesoscale defect densities. Bracketing the population of mesoscale hot spots that are active in the shocked ignition of explosives is important for the development of predictive reactive flow models. By coupling a multiphysics-capable hydrodynamics code (ale3d) with a chemical kinetics solver (cheetah), we can parametrically analyze different pore sizes undergoing collapse in high pressure shock conditions with evolving physical parameter fields. Implementing first-principles based decomposition kinetics, burning hot spots are monitored, and the regimes of pore sizes that contribute significantly to burnt mass faction and those that survive thermal conduction on the time scales of ignition are elucidated. Comparisons are drawn between the thermal explosion theory and the multiphysics models for the determination of nominal pore sizes that burn significantly during ignition for the explosive 1,3,5-triamino-2,4,6-trinitrobenzene.

  12. Determining agricultural land use scenarios in a mesoscale Bavarian watershed for modelling future water quality

    NASA Astrophysics Data System (ADS)

    Mehdi, B. B.; Ludwig, R.; Lehner, B.

    2012-06-01

    Land use scenarios are of primordial importance when implementing a hydrological model for the purpose of determining the future quality of water in a watershed. This paper provides the background for researching potential agricultural land use changes that may take place in a mesoscale watershed, for water quality research, and describes why studying the farm scale is important. An on-going study in Bavaria examining the local drivers of change in land use is described.

  13. Exploring the mesoscale activity in the Solomon Sea: A complementary approach with a numerical model and altimetric data

    NASA Astrophysics Data System (ADS)

    Gourdeau, L.; Verron, J.; Melet, A.; Kessler, W.; Marin, F.; Djath, B.

    2014-04-01

    The Solomon Sea is an area of high level of eddy kinetic energy (EKE), and represents a transit area for the low-latitude western boundary currents (LLWBCs) connecting the subtropics to the equatorial Pacific and playing a major role in ENSO dynamics. This study aims at documenting the surface mesoscale activity in the Solomon Sea for the first time. Our analysis is based on the joint analysis of altimetric data and outputs from a 1/12° model simulation. The highest surface EKE is observed in the northern part of the basin and extends southward to the central basin. An eddy tracking algorithm is used to document the characteristics and trajectories of coherent mesoscale vortices. Cyclonic eddies, generated in the south basin, are advected to the north by the LLWBCs before merging with stationary mesoscale structures present in the mean circulation. Anticyclonic eddies are less numerous. They are generated in the southeastern basin, propagate westward, reach the LLWBCs, and dissipate. The seasonal and interannual modulations of the mesoscale activity are well marked. At seasonal time scale, maximum (minimum) activity is in May-June (September). At interannual time scale, the mesoscale activity is particularly enhanced during La Niña conditions. If instabilities of the regional circulations seem to explain the generation of mesoscale features, the modulation of the mesoscale activity seems to be rather related with the intrusion at Solomon Strait of the surface South Equatorial Current, rather than to the LLWBCs, by modulating the horizontal and vertical shears suitable for instabilities.

  14. Simulating wind energy resources with mesoscale models: Intercomparison of state-of-the-art models over Northern Europe

    NASA Astrophysics Data System (ADS)

    Hahmann, A. N.

    2015-12-01

    Mesoscale models are increasingly being used to estimate wind conditions to identify perspective areas and sites where to develop wind farm projects. Mesoscale models are useful because they give information over extensive areas with various terrain complexities where measurements are scarce and measurement campaigns costly. Various mesoscale models and families of mesoscale models are being used, with thousands of setup options. Since long-term integrations are expensive and tedious to carry out, only limited comparisons exist. We have carried out a blind benchmarking study to evaluate the capabilities of mesoscale models used in wind energy to estimate site wind conditions: to highlight common issues on mesoscale modeling of wind conditions on sites with different characteristics, and to identify gaps and strengths of models and understand the root conditions for further evaluating uncertainties. Three experimental sites with tall mast measurements were selected: FINO3 (offshore), Høvsøre (coastal), and Cabauw (land-based). The participants were asked to provide hourly time series of wind speed and direction, temperature, etc., at various heights for 2011. The methods used were left to the choice of the participants, but they were asked for a detailed description of their model and many other parameters (e.g., horizontal and vertical resolution, model parameterizations, surface roughness length) that could be used to group the models and interpret the results of the intercomparison. The analysis of the time series includes comparison to observations, summarized with well-known measures such as biases, RMSE, correlations, and of sector-wise statistics, and the temporal spectra. The statistics were grouped by the models, their spatial resolution, forcing data, various integration methods, etc. The results show high fidelity of the various entries in simulating the wind climate at the offshore and coastal site. Over land and the statistics of other derived fields

  15. Macroscale modeling and mesoscale observations of plasma density structures in the polar cap

    SciTech Connect

    Basu, S.; Basu, S.; Sojka, J.J.; Schunk, R.W.; MacKenzie, E.

    1995-04-15

    The seasonal and UT variation of mesoscale structures (10 km - 100 m) in the central polar cap has been obtained from an analysis of 250-MHz intensity scintillation observations made at Thule, Greenland. It has been established earlier that mesoscale structures causing scintillations of satellite signals may develop at the edges of macroscale structures (several hundred km) such as discrete polar cap plasma density enhancements or patches through the gradient drift instability process. As such, the authrs examined the seasonal and UT variation of polar cap patches simulated by using the USU Time Dependent Ionospheric Model (TDIM) under conditions of southward B(sub z). A fairly remarkable similarity is found between the scintillation observations and the model predictions of patch occurrence. For instance, both the patch and scintillation occurrences are minimized during the winter solstice (northern hemisphere) between 0800-1200 UT while also having their largest seasonal intensity between 2000-2400 UT. Little UT dependence of patches and scintillations is seen at equinox with high intensity being observed throughout the day, while during local summer the intensity of macroscale patches and mesoscale irregularities are found to be a minimum at all UT. These results indicate that macroscale features in the polar cap are routinely associated with plasma instabilities giving rise to smaller scale structures and that the specific patch formation mechanism assumed in the simulation is consistent with the observations.

  16. Mesoscale modeling of combined aerosol and photo-oxidant processes in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Lazaridis, M.; Spyridaki, A.; Solberg, S.; Smolík, J.; Zdímal, V.; Eleftheriadis, K.; Aleksanropoulou, V.; Hov, O.; Georgopoulos, P. G.

    2005-03-01

    Particulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13-16 July 2000, 26-30 July 2000 and 7-14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. The objective of the current modeling work was mainly to apply the UAM-AERO mesoscale model in the eastern Mediterranean in order to assess the performed field campaigns and determine that the applied mesoscale model is fit for this purpose. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer and winter campaigns. Discrepancies between modeled and measured data are attributed to unresolved particulate matter emissions. Particulate matter in the area is mainly composed by sulphate, sea salt and crustal materials, and with significant amounts of nitrate, ammonium and organics. During winter the particulate matter and oxidant concentrations were lower than the summer values.

  17. Mesoscale modeling of lake effect snow over Lake Erie - sensitivity to convection, microphysics and the water temperature

    NASA Astrophysics Data System (ADS)

    Theeuwes, N. E.; Steeneveld, G. J.; Krikken, F.; Holtslag, A. A. M.

    2010-03-01

    Lake effect snow is a shallow convection phenomenon during cold air advection over a relatively warm lake. A severe case of lake effect snow over Lake Erie on 24 December 2001 was studied with the MM5 and WRF mesoscale models. This particular case provided over 200 cm of snow in Buffalo (NY), caused three casualties and 10 million of material damage. Hence, the need for a reliable forecast of the lake effect snow phenomenon is evident. MM5 and WRF simulate lake effect snow successfully, although the intensity of the snowbelt is underestimated. It appears that significant differences occur between using a simple and a complex microphysics scheme. In MM5, the use of the simple-ice microphysics scheme results in the triggering of the convection much earlier in time than with the more sophisticated Reisner-Graupel-scheme. Furthermore, we find a large difference in the maximum precipitation between the different nested domains: Reisner-Graupel produces larger differences in precipitation between the domains than "simple ice". In WRF, the sophisticated Thompson microphysics scheme simulates less precipitation than the simple WSM3 scheme. Increased temperature of Lake Erie results in an exponential growth in the 24-h precipitation. Regarding the convection scheme, the updated Kain-Fritsch scheme (especially designed for shallow convection during lake effect snow), gives only slight differences in precipitation between the updated and the original scheme.

  18. Toward an extended-geostrophic Euler-Poincare model for mesoscale oceanographic flow

    SciTech Connect

    Allen, J.S.; Newberger, P.A.; Holm, D.D.

    1998-07-01

    The authors consider the motion of a rotating, continuously stratified fluid governed by the hydrostatic primitive equations (PE). An approximate Hamiltonian (L1) model for small Rossby number {var_epsilon} is derived for application to mesoscale oceanographic flow problems. Numerical experiments involving a baroclinically unstable oceanic jet are utilized to assess the accuracy of the L1 model compared to the PE and to other approximate models, such as the quasigeostrophic (QG) and the geostrophic momentum (GM) equations. The results of the numerical experiments for moderate Rossby number flow show that the L1 model gives accurate solutions with errors substantially smaller than QG or GM.

  19. Modeling the wind-fields of accidental releases by mesoscale forecasting

    SciTech Connect

    Albritton, J.R.; Lee, R.L.; Mobley, R.L.; Pace, J.C.; Hodur, R.A.; Lion, C.S.

    1997-07-01

    Modeling atmospheric releases even during fair weather can present a sever challenge to diagnostic, observed-data-driven, models. Such schemes are often handicapped by sparse input data from meteorological surface stations and soundings. Forecasting by persistence is only acceptable for a few hours and cannot predict important changes in the diurnal cycle or from synoptic evolution. Many accident scenarios are data-sparse in space and/or time. Here we describe the potential value of limited-area, mesoscale, forecast models for real-time emergency response. Simulated wind-fields will be passed to ARAC`s operational models to produce improved forecasts of dispersion following accidents.

  20. Modeling the Energy Resolution of Xenon with NEST

    NASA Astrophysics Data System (ADS)

    Uvarov, Sergey

    2013-04-01

    In addition to explaining the mean yields, NEST (the Noble Element Simulation Technique) can also address the energy resolution degrading effects in noble elements, for both electron and nuclear recoils (ER and NR). Liquid and gaseous xenon will be presented as examples. A non-binomial recombination fluctuation model will be discussed which well describes the intrinsic, supra-Poissonian resolution observed in xenon. It is combined with electric field effects, the Fano factor, and detector efforts, such as finite light collection efficiency and PMT quantum efficiency. In matters of conflicting dark matter search results observed by experiments such as XENON100 and CoGeNT, a stochastic, non-analytic, partially non-Gaussian understanding of the energy resolution for low-energy, WIMP-like nuclear recoils may be part of the solution. ER-NR discrimination can be predicted well with such an understanding.

  1. Mesoscale simulations of two model systems in biophysics: from red blood cells to DNAs

    NASA Astrophysics Data System (ADS)

    Peng, Zhangli; Chen, Yeng-Long; Lu, Huijie; Pan, Zehao; Chang, Hsueh-Chia

    2015-12-01

    Computational modeling has become increasingly important in biophysics, but the great challenge in numerical simulations due to the multiscale feature of biological systems limits the capability of modeling in making discoveries in biology. Innovative multiscale modeling approaches are desired to bridge different scales from nucleic acids and proteins to cells and tissues. Although all-atom molecular dynamics has been successfully applied in many microscale biological processes such as protein folding, it is still prohibitively expensive for studying macroscale problems such as biophysics of cells and tissues. On the other hand, continuum-based modeling has become a mature procedure for analysis and design in many engineering fields, but new insights for biological systems in the microscale are limited when molecular details are missing in continuum-based modeling. In this context, mesoscale modeling approaches such as Langevin dynamics, lattice Boltzmann method, and dissipative particle dynamics have become popular by simultaneously incorporating molecular interactions and long-range hydrodynamic interactions, providing insights to properties on longer time and length scales than molecular dynamics. In this review, we summarized several mesoscale simulation approaches for studying two model systems in biophysics: red blood cells (RBCs) and deoxyribonucleic acids (DNAs). The RBC is a model system for cell mechanics and biological membranes, while the DNA represents a model system for biopolymers. We introduced the motivations of studying these problems and presented the key features of different mesoscale methods. Furthermore, we described the latest progresses in these methods and highlighted the major findings for modeling RBCs and DNAs. Finally, we also discussed the challenges and potential issues of different approaches.

  2. Utilization of satellite data in mesoscale models of severe weather

    NASA Technical Reports Server (NTRS)

    Warner, T. T.

    1983-01-01

    The impact of the diagnostic initialization of divergence on short-range precipitation forecasts produced by a model, a numerical study of a storm, collaborative modeling and diagnostic studies, and a numerical investigation of the impact of SEASAT surface wind data used in the static initialization of the North Atlantic Storm of 9-10 September 1978 are summerized.

  3. Coupled Air-ocean Nested Modeling Studies Of The Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Pullen, J.; Doyle, J.; Hodur, R.; Cummings, J.

    We have conducted simulations of the Adriatic Sea using the Navy Coastal Ocean Model (NCOM), with surface forcing provided by the atmospheric component of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS). Our aim is to document and investigate the response pattern of the Adriatic to the complex combined forcing of the bora winds and strong Po River run-off. Separate three- dimensional multivariate optimum interpolation (MVOI) analysis techniques are used to generate the initial conditions for both COAMPS and NCOM. First, we used a 6-km NCOM grid over the entire Mediterranean Sea, with forcing supplied by sur- face stresses from a 27-km COAMPS grid, also covering the entire Mediterranean Sea area. Both the atmospheric and ocean fields produced were part of independent 12-hour incremental data assimilation cycles over the time period of interest. The re- sulting NCOM forecasts were then used as lateral boundary conditions for a series of higher resolution (2 km) NCOM forecasts of the Adriatic Sea. In these forecasts, a set of surface stress fields from COAMPS, using a nested 4 km grid centered over the Adriatic Sea, were used to force the NCOM high-resolution ocean nest. In addition, the 2 km Adriatic Sea model is forced by observed daily river discharge values from the Po River. We have focused on the time period of winter and spring 2001 when there were several bora wind events documented by the pilot program observations taken in preparation for the fall and winter 2002-2003 Adriatic Current Experiment (ACE). In addition, we analyze results from a multi-month simulation in fall/winter 1999 to establish circu- lation patterns that may appear during the upcoming observational season. The ACE observations will include ADCP's, moored buoys, CTD sections, and radar sites. The observational programs will generate much data about the circulation of this shallow sea subjected to river floods and strong bora wind events. The main goals of our work are to

  4. Essays on pricing dynamics, price dispersion, and nested logit modelling

    NASA Astrophysics Data System (ADS)

    Verlinda, Jeremy Alan

    The body of this dissertation comprises three standalone essays, presented in three respective chapters. Chapter One explores the possibility that local market power contributes to the asymmetric relationship observed between wholesale costs and retail prices in gasoline markets. I exploit an original data set of weekly gas station prices in Southern California from September 2002 to May 2003, and take advantage of highly detailed station and local market-level characteristics to determine the extent to which spatial differentiation influences price-response asymmetry. I find that brand identity, proximity to rival stations, bundling and advertising, operation type, and local market features and demographics each influence a station's predicted asymmetric relationship between prices and wholesale costs. Chapter Two extends the existing literature on the effect of market structure on price dispersion in airline fares by modeling the effect at the disaggregate ticket level. Whereas past studies rely on aggregate measures of price dispersion such as the Gini coefficient or the standard deviation of fares, this paper estimates the entire empirical distribution of airline fares and documents how the shape of the distribution is determined by market structure. Specifically, I find that monopoly markets favor a wider distribution of fares with more mass in the tails while duopoly and competitive markets exhibit a tighter fare distribution. These findings indicate that the dispersion of airline fares may result from the efforts of airlines to practice second-degree price discrimination. Chapter Three adopts a Bayesian approach to the problem of tree structure specification in nested logit modelling, which requires a heavy computational burden in calculating marginal likelihoods. I compare two different techniques for estimating marginal likelihoods: (1) the Laplace approximation, and (2) reversible jump MCMC. I apply the techniques to both a simulated and a travel mode

  5. Comparison of Soil Hydraulic Parameterizations for Mesoscale Meteorological Models.

    NASA Astrophysics Data System (ADS)

    Braun, Frank J.; Schädler, Gerd

    2005-07-01

    Soil water contents, calculated with seven soil hydraulic parameterizations, that is, soil hydraulic functions together with the corresponding parameter sets, are compared with observational data. The parameterizations include the Campbell/Clapp-Hornberger parameterization that is often used by meteorologists and the van Genuchten/Rawls-Brakensiek parameterization that is widespread among hydrologists. The observations include soil water contents at several soil depths and atmospheric surface data; they were obtained within the Regio Klima Projekt (REKLIP) at three sites in the Rhine Valley in southern Germany and cover up to 3 yr with 10-min temporal resolution. Simulations of 48-h episodes, as well as series of daily simulations initialized anew every 24 h and covering several years, were performed with the “VEG3D” soil-vegetation model in stand-alone mode; furthermore, 48-h episodes were simulated with the model coupled to a one-dimensional atmospheric model. For the cases and soil types considered in this paper, the van Genuchten/Rawls-Brakensiek model gives the best agreement between observed and simulated soil water contents on average. Especially during episodes with medium and high soil water content, the van Genuchten/Rawls-Brakensiek model performs better than the Campbell/Clapp-Hornberger model.

  6. Numerical Weather Prediction Over Caucasus Region With Nested Grid Models

    NASA Astrophysics Data System (ADS)

    Davitashvili, Dr.; Kutaladze, Dr.; Kvatadze, Dr.

    2010-09-01

    Global atmosphere models, which describe the weather processes, give the general character of the weather but can't catch the smaller scale processes, especially local weather for the territories with compound topography. Small-scale processes such as convection often dominate the local weather, which cannot be explicitly represented in models with grid size more then 10 km. A much finer grid is required to properly simulate frontal structures and represent cumulus convection. Georgia lies to the south of the Major Caucasian Ridge and the Lesser Caucasus mountains occupy the southern part of Georgia. About 85 percent of the total land area occupies complex mountain ranges.Therefore for the territory of Georgia it is necessary to use atmosphere models with a very high resolution nested grid system taking into account main orographic features of the area. We have elaborated and configured Whether Research Forecast - Advanced Researcher Weather (WRF-ARW) model for Caucasus region considering geographical-landscape character, topography height, land use, soil type and temperature in deep layers, vegetation monthly distribution, albedo and others. Porting of WRF-ARW application to the grid was a good opportunity for running model on larger number of CPUs and storing large amount of data on the grid storage elements. On the grid WRF was compiled for both Open MP and MPI (Shared + Distributed memory) environment and WPS was compiled for serial environment using PGI (v7.1.6, MPI- version 1.2.7) on the platform Linux-x86. In searching of optimal execution time for time saving different model directory structures and storage schema was used. Simulations were performed using a set of 2 domains with horizontal grid-point resolutions of 15 and 5 km, both defined as those currently being used for operational forecasts The coarser domain is a grid of 94x102 points which covers the South Caucasus region, while the nested inner domain has a grid size of 70x70 points mainly

  7. Mesoscale models of dispersions stabilized by surfactants and colloids.

    PubMed

    van der Sman, R G M; Meinders, M B J

    2014-09-01

    In this paper we discuss and give an outlook on numerical models describing dispersions, stabilized by surfactants and colloidal particles. Examples of these dispersions are foams and emulsions. In particular, we focus on the potential of the diffuse interface models based on a free energy approach, which describe dispersions with the surface-active agent soluble in one of the bulk phases. The free energy approach renders thermodynamic consistent models with realistic sorption isotherms and adsorption kinetics. The free energy approach is attractive because of its ability to describe highly complex dispersions, such as emulsions stabilized by ionic surfactants, or surfactant mixtures and dispersions with surfactant micelles. We have classified existing numerical methods into classes, using either a Eulerian or a Lagrangian representation for fluid and for the surfactant/colloid. A Eulerian representation gives a more coarse-grained, mean field description of the surface-active agent, while a Lagrangian representation can deal with steric effects and larger complexity concerning geometry and (amphiphilic) wetting properties of colloids and surfactants. However, the similarity between the description of wetting properties of both Eulerian and Lagrangian models allows for the development of hybrid Eulerian/Lagrangian models having advantages of both representations. PMID:24980050

  8. Numerical simulations of Hurricane Bertha using a mesoscale atmospheric model

    SciTech Connect

    Buckley, R.L.

    1996-08-01

    The Regional Atmospheric Model System (RAMS) has been used to simulate Hurricane Bertha as it moved toward and onto shore during the period July 10--12, 1996. Using large-scale atmospheric data from 00 UTC, 11 July (Wednesday evening) to initialize the model, a 36-hour simulation was created for a domain centered over the Atlantic Ocean east of the Florida coast near Jacksonville. The simulated onshore impact time of the hurricane was much earlier than observed (due to the use of results from the large-scale model, which predicted early arrival). However, the movement of the hurricane center (eye) as it approached the North Carolina/South Carolina coast as simulated in RAMS was quite good. Observations revealed a northerly storm track off the South Carolina coast as it moved toward land. As it approached landfall, Hurricane Bertha turned to the north-northeast, roughly paralleling the North Carolina coast before moving inland near Wilmington. Large-scale model forecasts were unable to detect this change in advance and predicted landfall near Myrtle Beach, South Carolina; RAMS, however, correctly predicted the parallel coastal movement. For future hurricane activity in the southeast, RAMS is being configured to run in an operational model using input from the large-scale pressure data in hopes of providing more information on predicted hurricane movement and landfall location.

  9. Range-Specific High-resolution Mesoscale Model Setup

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.

    2013-01-01

    This report summarizes the findings from an AMU task to determine the best model configuration for operational use at the ER and WFF to best predict winds, precipitation, and temperature. The AMU ran test cases in the warm and cool seasons at the ER and for the spring and fall seasons at WFF. For both the ER and WFF, the ARW core outperformed the NMM core. Results for the ER indicate that the Lin microphysical scheme and the YSU PBL scheme is the optimal model configuration for the ER. It consistently produced the best surface and upper air forecasts, while performing fairly well for the precipitation forecasts. Both the Ferrier and Lin microphysical schemes in combination with the YSU PBL scheme performed well for WFF in the spring and fall seasons. The AMU has been tasked with a follow-on modeling effort to recommended local DA and numerical forecast model design optimized for both the ER and WFF to support space launch activities. The AMU will determine the best software and type of assimilation to use, as well as determine the best grid resolution for the initialization based on spatial and temporal availability of data and the wall clock run-time of the initialization. The AMU will transition from the WRF EMS to NU-WRF, a NASA-specific version of the WRF that takes advantage of unique NASA software and datasets. 37

  10. Intercomparison of mesoscale meteorological models for precipitation forecasting

    NASA Astrophysics Data System (ADS)

    Richard, E.; Cosma, S.; Benoit, R.; Binder, P.; Buzzi, A.; Kaufmann, P.

    In the framework of the RAPHAEL EU project, a series of past heavy precipitation events has been simulated with different meteorological models. Rainfall hindcasts and forecasts have been produced by four models in use at various meteorological services or research centres of Italy, Canada, France and Switzerland. The paper is focused on the comparison of the computed precipitation fields with the available surface observations. The comparison is carried out for three meteorological situations which lead to severe flashflood over the Toce-Ticino catchment in Italy (6599 km2) or the Ammer catchment (709 km2) in Germany. The results show that all four models reproduced the occurrence of these heavy precipitation events. The accuracy of the computed precipitation appears to be more case-dependent than model-dependent. The sensitivity of the computed rainfall to the boundary conditions (hindcast v. forecast) was found to be rather weak, indicating that a flood forecasting system based upon a numerical meteo-hydrological simulation could be feasible in an operational context.

  11. Mesoscale modelling of shock initiation in HMX-based explosives

    SciTech Connect

    Swift, D. C.; Mulford, R. N. R.; Winter, R. E.; Taylor, P.; Salisbury, D. A.; Harris, E. J.

    2002-01-01

    Motivation: predictive capability Want to predict initiation, detonics and performance given: {sm_bullet} Variations in composition {sm_bullet} Variations in morphology {sm_bullet}Different loading conditions Previous work on PBX and ANFO: need physically-based model rather than just mechanical calibrations

  12. Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics

    SciTech Connect

    Persson, Rasmus A. X.; Chu, Jhih-Wei; Voulgarakis, Nikolaos K.

    2014-11-07

    Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ϕ in coupling to the other equations of FHD. The resulting ϕ-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ϕ-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ϕ-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 Å, the ϕ-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.

  13. A sensitivity study of storm cyclones with a mesoscale model

    NASA Astrophysics Data System (ADS)

    Radtke, K. S.; Tetzlaff, G.

    2003-04-01

    Extra tropical storms caused noticeable damages in the last decades. The evolution of strong cyclones is investigated by simulations with the nonhydrostatic limited area model 'Lokal Modell' (LM) of the German Weather Service (DWD). Which Conditions become important to distinguish an common cyclone from an storm-cyclone? Intense cyclones are mostly characterised by two typical large-scale features: high baroclinicity along the track of the low pressure system and a region of high equivalent potential temperature. For this purpose the observed values of the horizontal temperature gradient and the distribution of air moisture are varied and were used as forcing data, in such a way the development of storms was modified. The forcing data for the LM were generated by the global model of the DWD. Therefore data of real cyclones, such as the low Ginger, which occurred in 2000, were used. As the LM simulates only a limited area, the lateral bounds become problematic because of the manipulated forcing data. A procedure is tested, in order to prevent these problems. In this manner ensembles of storm scenarios were produced. The effects of various conditions were studied. Here in particular the changes in the surface velocity field were of interest. In the case of Ginger, an increase of the temperature gradient about 10 K causes an increasing of the maximum velocity about 3 m/s.

  14. Evaluation of Korean wind map based on mesoscale model WRF

    NASA Astrophysics Data System (ADS)

    Byon, Jaeyoung; Choi, Young-Jean; Seo, Beom-Keun

    2010-05-01

    In order to encourage wind energy industry and assessment of wind resource in Korea, we establish wind resource map using numerical model over the Korean Peninsula. The model which is used in this study is Weather Research and Forecasting (WRF) that is developed in NCAR. A high resolution topography with a 100-m resolution and a land-use data which has a 30-m resolution are implemented over the Korean environment for the improvement of lower atmosphere forecast in WRF. WRF has conducted with a 1 km resolution which is forecasted using NCEP FNL data employed as initial and boundary condition. The WRF model has run for one year for the wind map over the South Korea. The running periods that is named as typical meteorological year (TMY) is determined by statistical method. The TMY represents mean atmospheric characteristics from 1998 to 2008. Strong wind occurs in eastern, southern coastal region, and Jeju island of Korea. Wind in the Korean Peninsula blows from northwest during most of the season, but from southeast during summer. High occurrence rate of main wind direction is shown in mountainous region of inland and coastal region. The performance of the TMY results over the South Korea is validated with radiosonde observation at 80m above ground level which is wind turbine hub height. Root-mean-square-error (RMSE) shows about 3-6 m/s for wind speed and mean absolute error is about 30-50 degree for wind direction. Korean wind map will be improved continuously by data assimilation and high resolution simulation less than 1 km.

  15. High resolution numerical modeling of mesoscale island wakes and sensitivity to static topographic relief data

    NASA Astrophysics Data System (ADS)

    Nunalee, C. G.; Horváth, Á.; Basu, S.

    2015-03-01

    Recent decades have witnessed a drastic increase in the fidelity of numerical weather prediction (NWP) modeling. Currently, both research-grade and operational NWP models regularly perform simulations with horizontal grid spacings as fine as 1 km. This migration towards higher resolution potentially improves NWP model solutions by increasing the resolvability of mesoscale processes and reducing dependency on empirical physics parameterizations. However, at the same time, the accuracy of high-resolution simulations, particularly in the atmospheric boundary layer (ABL), are also sensitive to orographic forcing which can have significant variability on the same spatial scale as, or smaller than, NWP model grids. Despite this sensitivity, many high resolution atmospheric simulations do not consider uncertainty with respect to selection of static terrain height dataset. In this paper, we use the Weather Research and Forecasting (WRF) model to simulate realistic cases of lower tropospheric flow over and downstream of mountainous islands using both the default global 30 s United States Geographic Survey terrain height dataset (GTOPO30) and the 3 s Shuttle Radar Topography Mission (SRTM) terrain height dataset. Our results demonstrate cases where the differences between GTOPO30-based and SRTM-based model terrain height are significant enough to produce entirely different orographic wake mechanics, such as vortex shedding vs. no vortex shedding. These results are also compared to MODIS visible satellite imagery and highlight the importance of considering uncertain static boundary conditions when running high-resolution mesoscale models.

  16. Mesoscale modeling of shear-thinning polymer solutions.

    PubMed

    Santos de Oliveira, I S; Fitzgerald, B W; den Otter, W K; Briels, W J

    2014-03-14

    We simulate the linear and nonlinear rheology of two different viscoelastic polymer solutions, a polyisobutylene solution in pristane and an aqueous solution of hydroxypropylcellulose, using a highly coarse-grained approach known as Responsive Particle Dynamics (RaPiD) model. In RaPiD, each polymer has originally been depicted as a spherical particle with the effects of the eliminated degrees of freedom accounted for by an appropriate free energy and transient pairwise forces. Motivated by the inability of this spherical particle representation to entirely capture the nonlinear rheology of both fluids, we extended the RaPiD model by introducing a deformable particle capable of elongation. A Finite-Extensible Non-Linear Elastic potential provides a free energy penalty for particle elongation. Upon disentangling, this deformability allows more time for particles to re-entangle with neighbouring particles. We show this process to be integral towards recovering the experimental nonlinear rheology, obtaining excellent agreement. We show that the nonlinear rheology is crucially dependent upon the maximum elongation and less so on the elasticity of the particles. In addition, the description of the linear rheology has been retained in the process. PMID:24628201

  17. MESOSCALE MODELLING OF SHOCK INITIATION IN HMX-BASED EXPLOSIVES

    SciTech Connect

    Mulford, R. N. R.; Swift, D. C.

    2001-01-01

    Hydrocode calculations we used to simulate initiation in single- and double-shock experiments on several HMX-based explosives. Variations in the reactive behavior of theee materials reflects the differences between binders in the material, providing information regarding the sensitivity of the explosive to the mechanical properties of the constituents. Materials considered are EDC-37, with a soft binder, PBX-9601, with a relatively malleable binder, and PIBX-9404, with a stiff binder. Bulk reactive behavior of these materials is dominated by the HMX component and should be comparable, while the mechanical response varies. The reactive flow model is temperature-dependent, based on a modified Arrhenius rate. Some unreacted material is allowed to react at a rate given by the state of the hotspot rather than the bulk state of the unreacted explosive, according to a length scale reflecting the hotspot size, and a time scale for thermal equilibration. The Arrhenius rate for HMX is wsumed to be the same for all compositions. The initiation data for different HMX-bwd explosives axe modelled by choosing plausible parameters to describe the reactive and dissipative properties of the binder, and hence the behavior of the hotspots in each formulation.

  18. Mesoscale modeling of shear-thinning polymer solutions

    NASA Astrophysics Data System (ADS)

    Santos de Oliveira, I. S.; Fitzgerald, B. W.; den Otter, W. K.; Briels, W. J.

    2014-03-01

    We simulate the linear and nonlinear rheology of two different viscoelastic polymer solutions, a polyisobutylene solution in pristane and an aqueous solution of hydroxypropylcellulose, using a highly coarse-grained approach known as Responsive Particle Dynamics (RaPiD) model. In RaPiD, each polymer has originally been depicted as a spherical particle with the effects of the eliminated degrees of freedom accounted for by an appropriate free energy and transient pairwise forces. Motivated by the inability of this spherical particle representation to entirely capture the nonlinear rheology of both fluids, we extended the RaPiD model by introducing a deformable particle capable of elongation. A Finite-Extensible Non-Linear Elastic potential provides a free energy penalty for particle elongation. Upon disentangling, this deformability allows more time for particles to re-entangle with neighbouring particles. We show this process to be integral towards recovering the experimental nonlinear rheology, obtaining excellent agreement. We show that the nonlinear rheology is crucially dependent upon the maximum elongation and less so on the elasticity of the particles. In addition, the description of the linear rheology has been retained in the process.

  19. Mesoscale to plant-scale models of nuclear waste reprocessing.

    SciTech Connect

    Noble, David Frederick; O'Hern, Timothy John; Moffat, Harry K.; Nemer, Martin B.; Domino, Stefan Paul; Rao, Rekha Ranjana; Cipiti, Benjamin B.; Brotherton, Christopher M.; Jove-Colon, Carlos F.; Pawlowski, Roger Patrick

    2010-09-01

    Imported oil exacerabates our trade deficit and funds anti-American regimes. Nuclear Energy (NE) is a demonstrated technology with high efficiency. NE's two biggest political detriments are possible accidents and nuclear waste disposal. For NE policy, proliferation is the biggest obstacle. Nuclear waste can be reduced through reprocessing, where fuel rods are separated into various streams, some of which can be reused in reactors. Current process developed in the 1950s is dirty and expensive, U/Pu separation is the most critical. Fuel rods are sheared and dissolved in acid to extract fissile material in a centrifugal contactor. Plants have many contacts in series with other separations. We have taken a science and simulation-based approach to develop a modern reprocessing plant. Models of reprocessing plants are needed to support nuclear materials accountancy, nonproliferation, plant design, and plant scale-up.

  20. Mesoscale Fossil Diversity and Ecosystem Modeling in the Cenozoic

    NASA Astrophysics Data System (ADS)

    Brooks, B.; Cervato, C.

    2008-12-01

    Numerous experiments of extant ecosystems have tested aspects of modern niche theory as they relate to the development and maintenance of species richness in a geographic area. As such, species richness has often been observed to be a consequence of heterogeneous conditions within the ecosystem provided by environmental gradients, moderate levels of disturbance, and complex trophic interactions that give rise to niche partitioning. By contrast some studies of the fossil record have focused on identifying governing parameters for paleodiversity using instead simplified models of ecosystem interaction, which violate principles of niche theory. To examine ecosystem diversity within the most recent 60 Ma, we analyzed the depositional environment and lithologies of 17,984 globally distributed marine fossil assemblages, focusing on the relationship between diversity and ecosystem gradients. Our results indicate that although there is a myriad of factors that can provide for high fossil diversity within a geographic area, only a few ecosystem gradients are needed to explain the majority of that diversity. Our findings are consistent with modern niche theory and may extend the robustness of this concept significantly through time.

  1. The Next Version of the Canadian Operational GEM Regional Mesoscale Model

    NASA Astrophysics Data System (ADS)

    Mailhot, J.; Belair, S.; Tremblay, A.; Lefaivre, L.; Bilodeau, B.; Glazer, A.; Patoine, A.; Talbot, D.

    2003-04-01

    A new mesoscale version of the GEM regional model in operation in Canada for numerical weather prediction has been under development for some time. The main changes to the modeling system comprise an increased resolution both in the horizontal (15 km instead of 24 km) and the vertical (43 levels instead of 28) and improvements to almost every aspects of the physics package. These include an improved formulation of the boundary layer to represent clouds with an unified moist turbulence approach, the Kain-Fritsch deep convection scheme, and the Tremblay mixed-phase condensation scheme with explicit microphysics, together with revisions to the cloud radiative optical properties. The effect of low-level blocking due to subgrid-scale orography based on the Lott-Miller scheme has also been included. The performance of the new mesoscale modeling system has been compared against the current operational model for two 6-week cycles during winter and summer 2002. Based on the North American radiosondes, significant improvements are found in the bias and RMS errors of winds and temperatures. Objective precipitation scores also show significant improvements in winter for the bias and threat scores in almost all precipitation categories, while the scores are more similar during summer.

  2. Creep damage characterization using nonlinear ultrasonic guided wave method: A mesoscale model

    NASA Astrophysics Data System (ADS)

    Xiang, Yanxun; Deng, Mingxi; Xuan, Fu-Zhen

    2014-01-01

    The early deformations in materials such as creep, plasticity, and fatigue damages have been proved to have a close relationship with the nonlinear effect of ultrasonic waves propagating in them. In the present paper, a theoretical mesoscale model of an ultrasonic non-destructive method has been proposed to evaluate creep deformed states based on nonlinear guided waves. The model developed here considers the nonlinear generation of Lamb waves response from precipitates variation in the dislocation network, which can be applicable to all precipitate stages including coherent and semi-coherent precipitates in the metallic alloy undergoing creep degradation. To verify the proposed model, experiments of titanium alloy Ti60 plates were carried out with different creep strains. An "increase-decrease" change of the acoustic nonlinearity of guided wave versus the creep life fraction has been observed. Based on microscopic images analyses, the mesoscale model was then applied to these creep damaged Ti60 specimens, which revealed a good accordance with the measured results of the nonlinear guided waves. It is shown that the change of the nonlinear Lamb wave depends on the variations of the α2 precipitation volume fraction, the dislocation density, the growth of the creep-voids, and the increasing mismatch of the phase velocities during the creep deformation process. The results indicate that the effect of the precipitate-dislocation interactions on the nonlinear guided wave is likely the dominant mechanism responsible for the change of nonlinear guided wave propagation in the crept materials.

  3. Coupling NMM Mesoscale Weather Forecast Model with CALMET for Wind Energy Applications

    NASA Astrophysics Data System (ADS)

    Radonjic, Z.; Chambers, D.; Telenta, B.; Music, S.; Janjic, Z.

    2009-04-01

    A new and advanced mesoscale NMM (Nonhydrostatic Mesoscale Model)embeded in the framework - Forecast Refinement System Host (FReSH), was used in this application on the fine scale resolution (2 by 2 km). CALMET the U.S. EPA meteorological preprocessor (part of the CALMET/CALPUFF long range regulatory system) then applied on the resolutions of 100 by 100 m and 250 by 250 m. This study investigates the validation of FReSH3/CALMET against two data sets obtained from the meteorological towers at heights 58 and 62 m above the ground. Data set 1 was for a site at the elevation of 581 m above sea level (asl). Data set 2 was for a site at the elevation of 694 m - asl. The system is validated through a comparison of 10 minutes wind data measured and predicted by FReSH and the CALMET models. Case studies are used to investigate the capability of the models to predict the winds at the potential wind energy sites as well to demonstrate that the both models can be used to generate realistic forecasts for the wind energy sites often located at the hilly terrain.

  4. Meso-scale Modeling of Self-assembly of Polymer-Grafted Nanoparticles

    NASA Astrophysics Data System (ADS)

    Mancini, Derrick; Deshmukh, Sanket; Sankaranarayanan, Subramanian

    2015-03-01

    We develop meso-scale models to explore the self-assembly behavior of polymer-grafted nanoparticles. Specifically, we study nanoparticles with grafts of the thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAM), which undergoes a coil-to-globule transition across the LCST at around 305 K. The atomic-scale mechanism of the coil-to-globule transition of polymers grafted nanoparticles and their interactions (agglomeration, assembly behavior) with other particles that are in its vicinity is poorly understood, yet knowledge about these interactions would enable designing novel self-assembled materials with well-defined structural and dynamical properties. Additionally, the effects of chemical nature, geometry, and morphology of the nanoparticle surface on the conformational transition of thermo-sensitive polymers is also unknown. We report on 1) development of all-atom models of polymer-grafted nanoparticles to conduct MD simulations at atomic-levels and 2) perform mesoscopic scaling of the conformational dynamics resulting from the atomistic simulations with the aid of coarse-grained or meso-scale models of PNIPAM and its composites. Coarse-grained simulations allow modeling of larger assemblies of polymer-grafted nanoparticles over longer time scales. This research used resources of the Center for Nanoscale Materials and the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract DE-AC02-06CH11357.

  5. Meso-Scale Modeling to Characterize Moisture Absorption of 3D Woven Composite

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan; Zhou, Chu-wei

    2016-03-01

    For polymer-matrix composites, moisture is expected to degrade their mechanical properties due to matrix plasticization and moisture introduced micro-scale defects. In this study, the moisture absorptions of bulk epoxy, unidirectional composite (UD) and 3D woven composite (3D WC) were tested. Two-stage features have been observed for all these three materials. Moisture properties for UD and 3D WC were found not in simple direct proportion to their matrix volume fractions. The moisture approach of UD was modeled including the effect of fiber/matrix interphase which promotes the moisture uptake. Then, meso-scale FE model for 3D WC was established to characterize the inhomogeneous moisture diffusion. The moisture properties of resin-rich region and fiber bundle in 3D WC were determined from water uptake experiments of bulk epoxy and UD, respectively. Through homogenizing moisture properties of surface and interior weave structures, a simplified theoretical sandwich moisture diffusion approach was established. The moisture weight gains of 3D WC predicted by both meso-scale FE model and simplified sandwich approach were well agreed with the experimental data.

  6. Meso-Scale Modeling to Characterize Moisture Absorption of 3D Woven Composite

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan; Zhou, Chu-wei

    2016-08-01

    For polymer-matrix composites, moisture is expected to degrade their mechanical properties due to matrix plasticization and moisture introduced micro-scale defects. In this study, the moisture absorptions of bulk epoxy, unidirectional composite (UD) and 3D woven composite (3D WC) were tested. Two-stage features have been observed for all these three materials. Moisture properties for UD and 3D WC were found not in simple direct proportion to their matrix volume fractions. The moisture approach of UD was modeled including the effect of fiber/matrix interphase which promotes the moisture uptake. Then, meso-scale FE model for 3D WC was established to characterize the inhomogeneous moisture diffusion. The moisture properties of resin-rich region and fiber bundle in 3D WC were determined from water uptake experiments of bulk epoxy and UD, respectively. Through homogenizing moisture properties of surface and interior weave structures, a simplified theoretical sandwich moisture diffusion approach was established. The moisture weight gains of 3D WC predicted by both meso-scale FE model and simplified sandwich approach were well agreed with the experimental data.

  7. Leatherback nests increasing significantly in Florida, USA; trends assessed over 30 years using multilevel modeling.

    PubMed

    Stewart, Kelly; Sims, Michelle; Meylan, Anne; Witherington, Blair; Brost, Beth; Crowder, Larry B

    2011-01-01

    Understanding population status for endangered species is critical to developing and evaluating recovery plans mandated by the Endangered Species Act. For sea turtles, changes in abundance are difficult to detect because most life stages occur in the water. Currently, nest counts are the most reliable way of assessing trends. We determined the rate of growth for leatherback turtle (Dermochelys coriacea) nest numbers in Florida (USA) using a multilevel Poisson regression. We modeled nest counts from 68 beaches over 30 years and, using beach-level covariates (including latitude), we allowed for partial pooling of information between neighboring beaches. This modeling approach is ideal for nest count data because it recognizes the hierarchical structure of the data while incorporating variables related to survey effort. Nesting has increased at all 68 beaches in Florida, with trends ranging from 3.1% to 16.3% per year. Overall, across the state, the number of nests has been increasing by 10.2% per year since 1979. Despite being a small population (probably < 1000 individuals), this nesting population may help achieve objectives in the federal recovery plan. This exponential growth rate mirrors trends observed for other Atlantic populations and may be driven partially by improved protection of nesting beaches. However, nesting is increasing even where beach protection has not been enhanced. Climate variability and associated marine food web dynamics, which could enhance productivity and reduce predators, may be driving this trend. PMID:21516903

  8. Determinants of wood thrush nest success: A multi-scale, model selection approach

    USGS Publications Warehouse

    Driscoll, M.J.L.; Donovan, T.; Mickey, R.; Howard, A.; Fleming, K.K.

    2005-01-01

    We collected data on 212 wood thrush (Hylocichla mustelina) nests in central New York from 1998 to 2000 to determine the factors that most strongly influence nest success. We used an information-theoretic approach to assess and rank 9 models that examined the relationship between nest success (i.e., the probability that a nest would successfully fledge at least 1 wood thrush offspring) and habitat conditions at different spatial scales. We found that 4 variables were significant predictors of nesting success for wood thrushes: (1) total core habitat within 5 km of a study site, (2) distance to forest-field edge, (3) total forest cover within 5 km of the study site, and (4) density and variation in diameter of trees and shrubs surrounding the nest. The coefficients of these predictors were all positive. Of the 9 models evaluated, amount of core habitat in the 5-km landscape was the best-fit model, but the vegetation structure model (i.e., the density of trees and stems surrounding a nest) was also supported by the data. Based on AIC weights, enhancement of core area is likely to be a more effective management option than any other habitat-management options explored in this study. Bootstrap analysis generally confirmed these results; core and vegetation structure models were ranked 1, 2, or 3 in over 50% of 1,000 bootstrap trials. However, bootstrap results did not point to a decisive model, which suggests that multiple habitat factors are influencing wood thrush nesting success. Due to model uncertainty, we used a model averaging approach to predict the success or failure of each nest in our dataset. This averaged model was able to correctly predict 61.1% of nest outcomes.

  9. Propagation of impact-induced shock waves in porous sandstone using mesoscale modeling

    NASA Astrophysics Data System (ADS)

    GÜLdemeister, Nicole; WÜNnemann, Kai; Durr, Nathanael; Hiermaier, Stefan

    2013-01-01

    Abstract-Generation and propagation of shock waves by meteorite impact is significantly affected by material properties such as porosity, water content, and strength. The objective of this work was to quantify processes related to the shock-induced compaction of pore space by numerical <span class="hlt">modeling</span>, and compare the results with data obtained in the framework of the Multidisciplinary Experimental and <span class="hlt">Modeling</span> Impact Research Network (MEMIN) impact experiments. We use <span class="hlt">mesoscale</span> <span class="hlt">models</span> resolving the collapse of individual pores to validate macroscopic (homogenized) approaches describing the bulk behavior of porous and water-saturated materials in large-scale <span class="hlt">models</span> of crater formation, and to quantify localized shock amplification as a result of pore space crushing. We carried out a suite of numerical <span class="hlt">models</span> of planar shock wave propagation through a well-defined area (the "sample") of porous and/or water-saturated material. The porous sample is either represented by a homogeneous unit where porosity is treated as a state variable (macroscale <span class="hlt">model</span>) and water content by an equation of state for mixed material (ANEOS) or by a defined number of individually resolved pores (<span class="hlt">mesoscale</span> <span class="hlt">model</span>). We varied porosity and water content and measured thermodynamic parameters such as shock wave velocity and particle velocity on meso- and macroscales in separate simulations. The <span class="hlt">mesoscale</span> <span class="hlt">models</span> provide additional data on the heterogeneous distribution of peak shock pressures as a consequence of the complex superposition of reflecting rarefaction waves and shock waves originating from the crushing of pores. We quantify the bulk effect of porosity, the reduction in shock pressure, in terms of Hugoniot data as a function of porosity, water content, and strength of a quartzite matrix. We find a good agreement between meso-, macroscale <span class="hlt">models</span> and Hugoniot data from shock experiments. We also propose a combination of a porosity compaction <span class="hlt">model</span> (ɛ-α <span class="hlt">model</span>) that was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.3920S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.3920S"><span id="translatedtitle">Impact of new aircraft observations Mode-S MRAR in a <span class="hlt">mesoscale</span> NWP <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strajnar, B.; Žagar, N.; Berre, L.</p> <p>2015-05-01</p> <p>The impact of recently available high-resolution Mode-S Meteorological Routine Air Report (MRAR) wind and temperature observations is evaluated in the <span class="hlt">mesoscale</span> numerical weather prediction (NWP) <span class="hlt">model</span> Aire Limitée Adaptation dynamique Développement InterNational (ALADIN). Data available from the airspace communicating with the Ljubljana Airport in Slovenia are assimilated by using the three-dimensional variational assimilation procedure on top of all other observations assimilated operationally. A data selection method based on aircraft type was shown to be important for the first application of the new observations in ALADIN. The evaluation of Mode-S MRAR impact included both winter and summer periods. In both seasons a clear improvement of wind and temperature forecasts was found for in the short forecast range, 1-3 h. The impact in the 24 h forecast range depends on season, with a consistent positive improvement of the boundary layer temperature forecasts obtained for the stable anticyclonic winter situations. In summer, the impact was mixed and it was found to be sensitive to the multivariate aspects of the moisture analysis. Overall presented results suggest that the new aircraft-derived observations Mode-S MRAR have a significant potential for <span class="hlt">mesoscale</span> NWP and improved data assimilation <span class="hlt">modeling</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.1154P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.1154P&link_type=ABSTRACT"><span id="translatedtitle">The impact of vertical resolution in <span class="hlt">mesoscale</span> <span class="hlt">model</span> AROME forecasting of radiation fog</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Philip, Alexandre; Bergot, Thierry; Bouteloup, Yves; Bouyssel, François</p> <p>2015-04-01</p> <p>Airports short-term forecasting of fog has a security and economic impact. Numerical simulations have been performed with the <span class="hlt">mesoscale</span> <span class="hlt">model</span> AROME (Application of Research to Operations at <span class="hlt">Mesoscale</span>) (Seity et al. 2011). Three vertical resolutions (60, 90 and 156 levels) are used to show the impact of radiation fog on numerical forecasting. Observations at Roissy Charles De Gaulle airport are compared to simulations. Significant differences in the onset, evolution and dissipation of fog were found. The high resolution simulation is in better agreement with observations than a coarser one. The surface boundary layer and incoming long-wave radiations are better represented. A more realistic behaviour of liquid water content evolution allows a better anticipation of low visibility procedures (ceiling < 60m and/or visibility < 600m). The case study of radiation fog shows that it is necessary to have a well defined vertical grid to better represent local phenomena. A statistical study over 6 months (October 2011 - March 2012 ) using different configurations was carried out. Statistically, results were the same as in the case study of radiation fog. Seity Y., P. Brousseau, S. Malardel, G. Hello, P. Bénard, F. Bouttier, C. Lac, V. Masson, 2011: The AROME-France convective scale operational <span class="hlt">model</span>. Mon.Wea.Rev., 139, 976-991.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGC41C1015W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGC41C1015W"><span id="translatedtitle">Projected changes of extreme precipitation over Contiguous United States with <span class="hlt">Nested</span> regional climate <span class="hlt">model</span> (NRCM)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, J.</p> <p>2013-12-01</p> <p>Extreme weather events have already significantly influenced North America. During 2005-2011, the extreme events have increased by 250 %, from four or fewer events occurring in 2005, while 14 events occurring in 2011 (www.ncdc.noaa.gov/billions/). In addition, extreme rainfall amounts, frequency, and intensity were all expected to increase under greenhouse warming scenarios (Wehner 2005; Kharin et al. 2007; Tebaldi et al. 2006). Global <span class="hlt">models</span> are powerful tools to investigate the climate and climate change on large scales. However, such <span class="hlt">models</span> do not represent local terrain and <span class="hlt">mesoscale</span> weather systems well owing to their coarse horizontal resolution (150-300 km). To capture the fine-scale features of extreme weather events, regional climate <span class="hlt">models</span> (RCMs) with a more realistic representation of the complex terrain and heterogeneous land surfaces are needed (Mass et al. 2002). This study uses the <span class="hlt">Nested</span> Regional Climate <span class="hlt">model</span> (NRCM) to perform regional scale climate simulations on a 12-km × 12-km high resolution scale over North America (including Alaska; with 600 × 515 grid cells at longitude and latitude), known as CORDEX_North America, instead of small regions as studied previously (eg., Dominguez et al. 2012; Gao et al. 2012). The performance and the biases of the NRCM extreme precipitation calculations (2000-2010) have been evaluated with PRISM precipitation (Daly et al. 1997) by Wang and Kotamarthi (2013): the NRCM replicated very well the monthly amount of extreme precipitation with less than 3% overestimation over East CONUS, and the frequency of extremes over West CONUS and upper Mississippi River Basin. The Representative Concentration Pathway (RCP) 8.5 and RCP 4.5 from the new Community Earth System <span class="hlt">Model</span> version 1.0 (CESM v1.0) are dynamically downscaled to predict the extreme rainfall events at the end-of-century (2085-2095) and to explore the uncertainties of future extreme precipitation induced by different scenarios over distinct regions. We have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999MAP....71..229G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999MAP....71..229G"><span id="translatedtitle">Effects of a Total Solar Eclipse on the <span class="hlt">Mesoscale</span> Atmospheric Circulation over Europe - A <span class="hlt">Model</span> Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gross, P.; Hense, A.</p> <p></p> <p>On August the 11th, 1999 Central Europe saw a spectacular astronomical event, a total solar eclipse. We present a <span class="hlt">model</span> study concerning the meteorological effects of this eclipse in central Europe using the state-of-the-art limited area forecast <span class="hlt">model</span> Deutschland-<span class="hlt">Modell</span> DM from the German Weather Service DWD. Under typical summer radiation conditions very strong anomalies in the surface energy flux and temperature in screen height are simulated. The main temperature signal in the lower troposphere is delayed by about one hour with respect to the surface. Furthermore it is connected with a well defined dynamical signal which is reminiscent to a large scale land - sea circulation. The event could be used as a test case for <span class="hlt">mesoscale</span> atmospheric <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1527539R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1527539R"><span id="translatedtitle">Controlled meteorological (CMET) balloon profiling of the Arctic atmospheric boundary layer around Spitsbergen compared to a <span class="hlt">mesoscale</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberts, T. J.; Dütsch, M.; Hole, L. R.; Voss, P. B.</p> <p>2015-10-01</p> <p>Observations from CMET (Controlled Meteorological) balloons are analyzed in combination with <span class="hlt">mesoscale</span> <span class="hlt">model</span> simulations to provide insights into tropospheric meteorological conditions (temperature, humidity, wind-speed) around Svalbard, European High Arctic. Five Controlled Meteorological (CMET) balloons were launched from Ny-Ålesund in Svalbard over 5-12 May 2011, and measured vertical atmospheric profiles above Spitsbergen Island and over coastal areas to both the east and west. One notable CMET flight achieved a suite of 18 continuous soundings that probed the Arctic marine boundary layer over a period of more than 10 h. The CMET profiles are compared to simulations using the Weather Research and Forecasting (WRF) <span class="hlt">model</span> using <span class="hlt">nested</span> grids and three different boundary layer schemes. Variability between the three <span class="hlt">model</span> schemes was typically smaller than the discrepancies between the <span class="hlt">model</span> runs and the observations. Over Spitsbergen, the CMET flights identified temperature inversions and low-level jets (LLJ) that were not captured by the <span class="hlt">model</span>. Nevertheless, the <span class="hlt">model</span> largely reproduced time-series obtained from the Ny-Ålesund meteorological station, with exception of surface winds during the LLJ. Over sea-ice east of Svalbard the <span class="hlt">model</span> underestimated potential temperature and overestimated wind-speed compared to the CMET observations. This is most likely due to the full sea-ice coverage assumed by the <span class="hlt">model</span>, and consequent underestimation of ocean-atmosphere exchange in the presence of leads or fractional coverage. The suite of continuous CMET soundings over a sea-ice free region to the northwest of Svalbard are analysed spatially and temporally, and compared to the <span class="hlt">model</span>. The observed along-flight daytime increase in relative humidity is interpreted in terms of the diurnal cycle, and in the context of marine and terrestrial air-mass influences. Analysis of the balloon trajectory during the CMET soundings identifies strong wind-shear, with a low-level channeled</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010037609','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010037609"><span id="translatedtitle">A Study of Heavy Precipitation Events in Taiwan During 10-13 August, 1994. Part 2; <span class="hlt">Mesoscale</span> <span class="hlt">Model</span> Simulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tao, Wei Kuo; Chen, C.-S.; Jia, Y.; Baker, D.; Lang, S.; Wetzel, P.; Lau, W. K.-M.</p> <p>2001-01-01</p> <p>Several heavy precipitation episodes occurred over Taiwan from August 10 to 13, 1994. Precipitation patterns and characteristics are quite different between the precipitation events that occurred from August 10 and I I and from August 12 and 13. In Part I (Chen et al. 2001), the environmental situation and precipitation characteristics are analyzed using the EC/TOGA data, ground-based radar data, surface rainfall patterns, surface wind data, and upper air soundings. In this study (Part II), the Penn State/NCAR <span class="hlt">Mesoscale</span> <span class="hlt">Model</span> (MM5) is used to study the precipitation characteristics of these heavy precipitation events. Various physical processes (schemes) developed at NASA Goddard Space Flight Center (i.e., cloud microphysics scheme, radiative transfer <span class="hlt">model</span>, and land-soil-vegetation surface <span class="hlt">model</span>) have recently implemented into the MM5. These physical packages are described in the paper, Two way interactive <span class="hlt">nested</span> grids are used with horizontal resolutions of 45, 15 and 5 km. The <span class="hlt">model</span> results indicated that Cloud physics, land surface and radiation processes generally do not change the location (horizontal distribution) of heavy precipitation. The Goddard 3-class ice scheme produced more rainfall than the 2-class scheme. The Goddard multi-broad-band radiative transfer <span class="hlt">model</span> reduced precipitation compared to a one-broad band (emissivity) radiation <span class="hlt">model</span>. The Goddard land-soil-vegetation surface <span class="hlt">model</span> also reduce the rainfall compared to a simple surface <span class="hlt">model</span> in which the surface temperature is computed from a Surface energy budget following the "force-re store" method. However, <span class="hlt">model</span> runs including all Goddard physical processes enhanced precipitation significantly for both cases. The results from these runs are in better agreement with observations. Despite improved simulations using different physical schemes, there are still some deficiencies in the <span class="hlt">model</span> simulations. Some potential problems are discussed. Sensitivity tests (removing either terrain or radiative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A43A3240T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A43A3240T&link_type=ABSTRACT"><span id="translatedtitle">Characterization of <span class="hlt">Mesoscale</span> Variability in WRF - a Coastal Low-Level Jet Case Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tay, K.; Lundquist, J. K.; Skote, M.; Koh, T. Y.</p> <p>2014-12-01</p> <p><span class="hlt">Mesoscale</span> weather <span class="hlt">models</span> have increasingly been featured in wind resource assessment development. The incorporation of real meteorological conditions into such assessments allow a more realistic, physical determination of the wind loads that will be experienced within a wind farm site. Large-Eddy Simulation (LES) confers the advantage of representing finer scale turbulence, such as wake effects. However, <span class="hlt">nesting</span> LES within real <span class="hlt">mesoscale</span> simulations is still in the nascent stage of development. One of the difficulties lies in providing accurate <span class="hlt">mesoscale</span> forcing boundaries for the LES domain. This study aims to characterize the <span class="hlt">mesoscale</span> variability in WRF to lay the groundwork for future <span class="hlt">mesoscale</span>-LES <span class="hlt">nested</span> simulations. A low-level jet (LLJ) event that was observed during the CBLAST-Low 2001 campaign (07 Aug to 09 Aug) provides a robust case study to test the capabilities of and characterize the <span class="hlt">mesoscale</span> variabilities in WRF. The dynamical interaction of a frontal passage with a stable boundary layer over a coastal region makes this an interesting and challenging case for real <span class="hlt">mesoscale</span> simulation and future LES <span class="hlt">nested</span> simulations. Sensitivities to vertical resolution, PBL schemes and initial forcing datasets were tested. This presentation will describe and explain the factors that influence the simulation of this frontal passage and the resulting LLJ. The initial forcing datasets have a major influence on spatial and temporal characteristics, as seen in Figure 1, introducing larger differences than the PBL schemes do. Furthermore, the <span class="hlt">mesoscale</span> simulation also showed a strong dependence on the vertical resolution: increasing the vertical resolution within the atmospheric boundary layer resulted in a more accurate vertical profile for wind speed. Lastly, the simulations did show a dependency on the PBL scheme selected however, the variability between PBL schemes were not large, especially compared to the variability introduced by the boundary and initial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23584035','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23584035"><span id="translatedtitle">Issues related to aircraft take-off plumes in a <span class="hlt">mesoscale</span> photochemical <span class="hlt">model</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bossioli, Elissavet; Tombrou, Maria; Helmis, Costas; Kurtenbach, Ralf; Wiesen, Peter; Schäfer, Klaus; Dandou, Aggeliki; Varotsos, Kostas V</p> <p>2013-07-01</p> <p>The physical and chemical characteristics of aircraft plumes at the take-off phase are simulated with the <span class="hlt">mesoscale</span> CAMx <span class="hlt">model</span> using the individual plume segment approach, in a highly resolved domain, covering the Athens International Airport. Emission indices during take-off measured at the Athens International Airport are incorporated. <span class="hlt">Model</span> predictions are compared with in situ point and path-averaged observations (NO, NO₂) downwind of the runway at the ground. The influence of <span class="hlt">modeling</span> process, dispersion properties and background air composition on the chemical evolution of the aircraft plumes is examined. It is proven that the mixing properties mainly determine the plume dispersion. The initial plume properties become significant for the selection of the appropriate vertical resolution. Besides these factors, the background NOx and O₃ concentration levels control NOx distribution and their conversion to nitrogen reservoir species. PMID:23584035</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GMD.....8.2645N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GMD.....8.2645N"><span id="translatedtitle">High-resolution numerical <span class="hlt">modeling</span> of <span class="hlt">mesoscale</span> island wakes and sensitivity to static topographic relief data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nunalee, C. G.; Horváth, Á.; Basu, S.</p> <p>2015-08-01</p> <p>Recent decades have witnessed a drastic increase in the fidelity of numerical weather prediction (NWP) <span class="hlt">modeling</span>. Currently, both research-grade and operational NWP <span class="hlt">models</span> regularly perform simulations with horizontal grid spacings as fine as 1 km. This migration towards higher resolution potentially improves NWP <span class="hlt">model</span> solutions by increasing the resolvability of <span class="hlt">mesoscale</span> processes and reducing dependency on empirical physics parameterizations. However, at the same time, the accuracy of high-resolution simulations, particularly in the atmospheric boundary layer (ABL), is also sensitive to orographic forcing which can have significant variability on the same spatial scale as, or smaller than, NWP <span class="hlt">model</span> grids. Despite this sensitivity, many high-resolution atmospheric simulations do not consider uncertainty with respect to selection of static terrain height data set. In this paper, we use the Weather Research and Forecasting (WRF) <span class="hlt">model</span> to simulate realistic cases of lower tropospheric flow over and downstream of mountainous islands using the default global 30 s United States Geographic Survey terrain height data set (GTOPO30), the Shuttle Radar Topography Mission (SRTM), and the Global Multi-resolution Terrain Elevation Data set (GMTED2010) terrain height data sets. While the differences between the SRTM-based and GMTED2010-based simulations are extremely small, the GTOPO30-based simulations differ significantly. Our results demonstrate cases where the differences between the source terrain data sets are significant enough to produce entirely different orographic wake mechanics, such as vortex shedding vs. no vortex shedding. These results are also compared to MODIS visible satellite imagery and ASCAT near-surface wind retrievals. Collectively, these results highlight the importance of utilizing accurate static orographic boundary conditions when running high-resolution <span class="hlt">mesoscale</span> <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007sos..symp...87M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007sos..symp...87M"><span id="translatedtitle">Optical Turbulence simulations with <span class="hlt">meso-scale</span> <span class="hlt">models</span>. Towards a new ground-based astronomy era</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masciadri, Elena</p> <p></p> <p>The optical turbulence characterization made with atmospherical <span class="hlt">meso-scale</span> <span class="hlt">models</span> for astronomical applications is a relatively recent approach (first studies have been published in the ninety). Simulations retrieved from such <span class="hlt">models</span> can be fundamental for the optimization of the AO techniques and characterization and selection of astronomical sites. In most cases, simulations and measurements provide complementary information on turbulence features. The potentialities related to the numerical approach and the most fundamental scientific challenges related to <span class="hlt">meso-scale</span> atmospheric <span class="hlt">models</span> rely upon the possibility (1) to describe a 3D map of the CN2 in a region around a telescope, (2) to forecast the optical turbulence i.e. to know with some hours in advance the state of the turbulence conditions above an astronomical site and (3) to perform a climatology of the optical turbulence extended over decades. The forecast of the optical turbulence is a fundamental requirement for the optimization of the management of the scientific programs to be carried out at ground-based telescopes foci. Ground-based astronomy will remain competitive with respect to the space-based one only if telescopes management will be performed taking advantage of the best turbulence conditions. The future of new ground- based telescopes generation relies therefore upon the success of these studies. No other tool of investigation with comparable potentialities can be figured out at present to achieve these 3 scientific goals. However, these highly challenging goals are associated to an intrinsic difficulty in parameterizing a physical process such as turbulence evolving at spatial and temporal scales smaller than what usually resolved by a <span class="hlt">meso-scale</span> <span class="hlt">model</span>. In this talk I will summarize the main results and progress achieved so far in this field since the ninety and I will present the most important scientific goals for the near and far future research. I will conclude with a brief presentation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010901','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010901"><span id="translatedtitle">Nonhydrostatic effects in numerical <span class="hlt">modeling</span> of <span class="hlt">mesoscale</span> convective systems and baroclinic waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cohen, Charles</p> <p>1993-01-01</p> <p>The present investigation is concerned with the role of convection upon <span class="hlt">mesoscale</span> <span class="hlt">modeling</span> results, particularly when the grid resolution becomes small enough that there is not a clear scale separation between the explicitly resolved circulations and the parameterized clouds. In those situations, the vertical accelerations in explicitly resolved circulations become strong enough that the hydrostatic assumption may no longer be valid. These concerns arise from interests in improving <span class="hlt">mesoscale</span> <span class="hlt">modeling</span> per se and in improving the subgrid-scale parameterizations in global <span class="hlt">models</span>. The hydrostatic and the nonhydrostatic options of the Colorado State University Regional Atmospheric <span class="hlt">Modeling</span> System were used to simulate dry gravity currents in two dimensions, using several different horizontal grid sizes. With horizontal grid intervals of 10 km or less, nonhydrostatic simulations produce wider and colder heads and weaker but wider forced updrafts than do the hydrostatic simulations. Comparing the hydrostatic and nonhydrostatic <span class="hlt">models</span> show that the difference between the vertical mass fluxes is much less than the difference between the vertical velocities. When the grid is fine enough to resolve the head of the gravity current, horizontal convergence at the gust front extends upwards almost to the head of the cold air. Vertical mass flux in the forced updraft at the front varies with horizontal grid size mainly as a function of the height of the simulated head. For coarser grids, which do not resolve the head, vertical mass flux at all heights decreases with increasing horizontal grid size. A comparison on nonhydrostatic simulations with horizontal grid intervals of 1 km and 2 km illustrates how decreasing the grid size does not necessarily increase the intensity of the resolved circulation. The smaller grid enables the simulated gravity current to entrain a bubble of warm air behind the head, which results in a weaker circulation with a shorter head and weaker updraft.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Geomo.256...68V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Geomo.256...68V&link_type=ABSTRACT"><span id="translatedtitle">Simulating <span class="hlt">mesoscale</span> coastal evolution for decadal coastal management: A new framework integrating multiple, complementary <span class="hlt">modelling</span> approaches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Maanen, Barend; Nicholls, Robert J.; French, Jon R.; Barkwith, Andrew; Bonaldo, Davide; Burningham, Helene; Brad Murray, A.; Payo, Andres; Sutherland, James; Thornhill, Gillian; Townend, Ian H.; van der Wegen, Mick; Walkden, Mike J. A.</p> <p>2016-03-01</p> <p>Coastal and shoreline management increasingly needs to consider morphological change occurring at decadal to centennial timescales, especially that related to climate change and sea-level rise. This requires the development of morphological <span class="hlt">models</span> operating at a <span class="hlt">mesoscale</span>, defined by time and length scales of the order 101 to 102 years and 101 to 102 km. So-called 'reduced complexity' <span class="hlt">models</span> that represent critical processes at scales not much smaller than the primary scale of interest, and are regulated by capturing the critical feedbacks that govern landform behaviour, are proving effective as a means of exploring emergent coastal behaviour at a landscape scale. Such <span class="hlt">models</span> tend to be computationally efficient and are thus easily applied within a probabilistic framework. At the same time, reductionist <span class="hlt">models</span>, built upon a more detailed description of hydrodynamic and sediment transport processes, are capable of application at increasingly broad spatial and temporal scales. More qualitative <span class="hlt">modelling</span> approaches are also emerging that can guide the development and deployment of quantitative <span class="hlt">models</span>, and these can be supplemented by varied data-driven <span class="hlt">modelling</span> approaches that can achieve new explanatory insights from observational datasets. Such disparate approaches have hitherto been pursued largely in isolation by mutually exclusive <span class="hlt">modelling</span> communities. Brought together, they have the potential to facilitate a step change in our ability to simulate the evolution of coastal morphology at scales that are most relevant to managing erosion and flood risk. Here, we advocate and outline a new integrated <span class="hlt">modelling</span> framework that deploys coupled <span class="hlt">mesoscale</span> reduced complexity <span class="hlt">models</span>, reductionist coastal area <span class="hlt">models</span>, data-driven approaches, and qualitative conceptual <span class="hlt">models</span>. Integration of these heterogeneous approaches gives rise to <span class="hlt">model</span> compositions that can potentially resolve decadal- to centennial-scale behaviour of diverse coupled open coast, estuary and inner</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880060530&hterms=pea&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpea','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880060530&hterms=pea&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpea"><span id="translatedtitle"><span class="hlt">Mesoscale</span> spiral vortex embedded within a Lake Michigan snow squall band - High resolution satellite observations and numerical <span class="hlt">model</span> simulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyons, Walter A.; Keen, Cecil S.; Hjelmfelt, Mark; Pease, Steven R.</p> <p>1988-01-01</p> <p>It is known that Great Lakes snow squall convection occurs in a variety of different modes depending on various factors such as air-water temperature contrast, boundary-layer wind shear, and geostrophic wind direction. An exceptional and often neglected source of data for <span class="hlt">mesoscale</span> cloud studies is the ultrahigh resolution multispectral data produced by Landsat satellites. On October 19, 1972, a clearly defined spiral vortex was noted in a Landsat-1 image near the southern end of Lake Michigan during an exceptionally early cold air outbreak over a still very warm lake. In a numerical simulation using a three-dimensional Eulerian hydrostatic primitive equation <span class="hlt">mesoscale</span> <span class="hlt">model</span> with an initially uniform wind field, a definite analog to the observed vortex was generated. This suggests that intense surface heating can be a principal cause in the development of a low-level <span class="hlt">mesoscale</span> vortex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1222552','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1222552"><span id="translatedtitle">A creep-damage <span class="hlt">model</span> for <span class="hlt">mesoscale</span> simulations of concrete expansion-degradation phenomena</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Giorla, Alain B; Le Pape, Yann</p> <p>2015-01-01</p> <p>Long-term performance of aging concrete in nuclear power plants (NPPs) requires a careful examination of the physical phenomena taking place in the material. Concrete under high neutron irradiation is subjected to large irreversible deformations as well as mechanical damage, caused by a swelling of the aggregates. However, these results, generally obtained in accelerated conditions in test reactors, cannot be directly applied to NPP irradiated structures, i.e., the biological shield, operating conditions due to difference in time scale and environmental conditions (temperature, humidity). <span class="hlt">Mesoscale</span> numerical simulations are performed to separate the underlying mechanisms and their interactions. The cement paste creep-damage <span class="hlt">model</span> accounts for the effect of the loading rate on the apparent damage properties of the material and uses an event-based approach to capture the competition between creep and damage. The <span class="hlt">model</span> is applied to the simulation of irradiation experiments from the literature and shows a good agreement with the experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dceg.cancer.gov/tools/analysis/nested-cohort','NCI'); return false;" href="http://dceg.cancer.gov/tools/analysis/nested-cohort"><span id="translatedtitle"><span class="hlt">Nested</span> Cohort</span></a></p> <p><a target="_blank" href="http://www.cancer.gov">Cancer.gov</a></p> <p></p> <p></p> <p><span class="hlt">Nested</span>Cohort is an R software package for fitting Kaplan-Meier and Cox <span class="hlt">Models</span> to estimate standardized survival and attributable risks for studies where covariates of interest are observed on only a sample of the cohort.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22230857','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22230857"><span id="translatedtitle">Hybrid <span class="hlt">nested</span> sampling algorithm for Bayesian <span class="hlt">model</span> selection applied to inverse subsurface flow problems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Elsheikh, Ahmed H.; Wheeler, Mary F.; Hoteit, Ibrahim</p> <p>2014-02-01</p> <p>A Hybrid <span class="hlt">Nested</span> Sampling (HNS) algorithm is proposed for efficient Bayesian <span class="hlt">model</span> calibration and prior <span class="hlt">model</span> selection. The proposed algorithm combines, <span class="hlt">Nested</span> Sampling (NS) algorithm, Hybrid Monte Carlo (HMC) sampling and gradient estimation using Stochastic Ensemble Method (SEM). NS is an efficient sampling algorithm that can be used for Bayesian calibration and estimating the Bayesian evidence for prior <span class="hlt">model</span> selection. <span class="hlt">Nested</span> sampling has the advantage of computational feasibility. Within the <span class="hlt">nested</span> sampling algorithm, a constrained sampling step is performed. For this step, we utilize HMC to reduce the correlation between successive sampled states. HMC relies on the gradient of the logarithm of the posterior distribution, which we estimate using a stochastic ensemble method based on an ensemble of directional derivatives. SEM only requires forward <span class="hlt">model</span> runs and the simulator is then used as a black box and no adjoint code is needed. The developed HNS algorithm is successfully applied for Bayesian calibration and prior <span class="hlt">model</span> selection of several nonlinear subsurface flow problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950052180&hterms=katabatic+winds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkatabatic%2Bwinds','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950052180&hterms=katabatic+winds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkatabatic%2Bwinds"><span id="translatedtitle">A <span class="hlt">mesoscale</span> <span class="hlt">modeling</span> study of the atmospheric circulation of high southern latitudes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hines, K. M.; Bromwich, David H.; Parish, T. R.</p> <p>1995-01-01</p> <p>The meteorology of high southern latitudes during winter is simulated using a cloud-free version of The Pennsylvania State University-National Center for Atmospheric Research <span class="hlt">Mesoscale</span> <span class="hlt">Model</span> version 4 (MM4) with a 100-km horizontal resolution. Comparisons between idealized simulations of Antarctic with MM4 and with the <span class="hlt">mesoscale</span> <span class="hlt">model</span> of Parish and Waight reveal that both <span class="hlt">models</span> produce similarly realistic velocity fields in the boundary layer. The latter <span class="hlt">model</span> tends to produce slightly faster drainage winds over East Antarctica. The intensity of the katabatic winds produced by MM4 is sensitive to parameterizations of boundary layer fluxes. Two simulations performed with MM4 using analyses from the European Center for Medium-Range Weather Forecasts (ECMWF) for June 1988 as initial and boundary conditions. A simulation of the period from 000 UTC 2 June to 0000 UTC 8 June produces realistic synoptic phenomena including ridge development over East Antarctica, frontogenesis over the Amundsen Sea, and a katabatic surge over the Ross Ice Shelf. The simulated time-averaged fields for June 1988, particularly that of a 500-hPa height, are in good agreement with time-averaged fields analyzed by the ECMWF. The results of the simulations provide detailed features of the Antarctic winter boundary layer along the steeply sloping terrain. Highest boundary layer wind speeds averaged over the month-long simulation are approximately 20 m/s. The lack of latent heating in the simulations apparently results in some bias in the results. In particular, the cloud-free version of MM4 underpredicts the intensity of lows in the sea level pressure field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.A44D..04K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.A44D..04K"><span id="translatedtitle">Investigation of flow transition problems at WRFs <span class="hlt">nested</span>-domain interfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirkil, G.; Mirocha, J.</p> <p>2010-12-01</p> <p>Many contemporary atmospheric simulation <span class="hlt">models</span> employ a grid <span class="hlt">nesting</span> capability that permits large-eddy simulations (LES) to be conducted over subsets of larger bounding simulations, with the bounding-domain solutions providing lateral boundary conditions for the <span class="hlt">nested</span> domains within. This approach can provide lateral boundary conditions that include <span class="hlt">mesoscale</span> features and the effects of upstream topography and land cover for the LES. Such an approach is particularly applicable to wind power forecasting, especially over complex terrain, for which <span class="hlt">mesoscale</span> flow conditions, local terrain effects and turbulence information can all be important. While grid <span class="hlt">nesting</span> has been successfully applied at GCM to <span class="hlt">mesoscale</span> resolutions, such <span class="hlt">nesting</span> behavior at higher resolutions, including those appropriate for LES, is less well understood. We investigate such grid <span class="hlt">nesting</span> capabilities for conducting an LES inside both larger-scale LES and <span class="hlt">mesoscale</span> simulations using the Weather Research and Forecasting (WRF) <span class="hlt">model</span>. Comparisons among the velocity and stress profiles inside the <span class="hlt">nested</span> domain relative to both the outer domain and non-<span class="hlt">nested</span> simulations indicate that errors contributed from the bounding domains are observed within the <span class="hlt">nested</span>-domain solution. We also examine the spatial scales required for flow structures to equilibrate to the finer mesh as flow enters a <span class="hlt">nest</span>, and how equilibration depends on several parameters, including mesh resolution and the type of turbulence subfilter-scale stress <span class="hlt">model</span> used. We outline approaches for addressing each of these issues, and provide progress to date. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-451371</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=257882&keyword=go&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77934621&CFTOKEN=77279243','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=257882&keyword=go&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77934621&CFTOKEN=77279243"><span id="translatedtitle">User’s manual for basic version of MCnest Markov chain <span class="hlt">nest</span> productivity <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The Markov Chain <span class="hlt">Nest</span> Productivity <span class="hlt">Model</span> (or MCnest) integrates existing toxicity information from three standardized avian toxicity tests with information on species life history and the timing of pesticide applications relative to the timing of avian breeding seasons to quantit...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=257881&keyword=go&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77934621&CFTOKEN=77279243','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=257881&keyword=go&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=77934621&CFTOKEN=77279243"><span id="translatedtitle">Technical manual for basic version of the Markov chain <span class="hlt">nest</span> productivity <span class="hlt">model</span> (MCnest)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The Markov Chain <span class="hlt">Nest</span> Productivity <span class="hlt">Model</span> (or MCnest) integrates existing toxicity information from three standardized avian toxicity tests with information on species life history and the timing of pesticide applications relative to the timing of avian breeding seasons to quantit...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015OcSci..11..667L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015OcSci..11..667L&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mesoscale</span> variability in the Arabian Sea from HYCOM <span class="hlt">model</span> results and observations: impact on the Persian Gulf Water path</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>L'Hégaret, P.; Duarte, R.; Carton, X.; Vic, C.; Ciani, D.; Baraille, R.; Corréard, S.</p> <p>2015-09-01</p> <p>The Arabian Sea and Sea of Oman circulation and water masses, subject to monsoon forcing, reveal a strong seasonal variability and intense <span class="hlt">mesoscale</span> features. We describe and analyze this variability and these features, using both meteorological data (from ECMWF reanalyses), in situ observations (from the ARGO float program and the GDEM - Generalized Digital Environmental mode - climatology), satellite altimetry (from AVISO) and a regional simulation with a primitive equation <span class="hlt">model</span> (HYCOM - the Hybrid Coordinate Ocean <span class="hlt">Model</span>). The <span class="hlt">model</span> and observations display comparable variability, and the <span class="hlt">model</span> is then used to analyze the three-dimensional structure of eddies and water masses with higher temporal and spatial resolutions than the available observations. The <span class="hlt">mesoscale</span> features are highly seasonal, with the formation of coastal currents, destabilizing into eddies, or the radiation of Rossby waves from the Indian coast. The <span class="hlt">mesoscale</span> eddies have a deep dynamical influence and strongly drive the water masses at depth. In particular, in the Sea of Oman, the Persian Gulf Water presents several offshore ejection sites and a complex recirculation, depending on the <span class="hlt">mesoscale</span> eddies. The associated mechanisms range from coastal ejection via dipoles, alongshore pulses due to a cyclonic eddy, to the formation of lee eddies downstream of Ra's Al Hamra. This water mass is also captured inside the eddies via several mechanisms, keeping high thermohaline characteristics in the Arabian Sea. The variations of the outflow characteristics near the Strait of Hormuz are compared with variations downstream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=146423&keyword=Michael+AND+Brown&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=76933125&CFTOKEN=39151615','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=146423&keyword=Michael+AND+Brown&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=76933125&CFTOKEN=39151615"><span id="translatedtitle">EXPERIMENTAL AND <span class="hlt">MODEL</span>-COMPUTED AREA AVERAGED VERTICAL PROFILES OF WIND SPEED FOR EVALUATION OF <span class="hlt">MESOSCALE</span> URBAN CANOPY SCHEMES</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Numerous urban canopy schemes have recently been developed for <span class="hlt">mesoscale</span> <span class="hlt">models</span> in order to approximate the drag and turbulent production effects of a city on the air flow. However, little data exists by which to evaluate the efficacy of the schemes since "area-averaged&quo...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JChPh.141k5101N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JChPh.141k5101N"><span id="translatedtitle">Thermomechanical stability and mechanochemical response of DNA: A minimal <span class="hlt">mesoscale</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nisoli, Cristiano; Bishop, A. R.</p> <p>2014-09-01</p> <p>We show that a <span class="hlt">mesoscale</span> <span class="hlt">model</span>, with a minimal number of parameters, can well describe the thermomechanical and mechanochemical behavior of homogeneous DNA at thermal equilibrium under tension and torque. We predict critical temperatures for denaturation under torque and stretch, phase diagrams for stable DNA, probe/response profiles under mechanical loads, and the density of dsDNA as a function of stretch and twist. We compare our predictions with available single molecule manipulation experiments and find strong agreement. In particular we elucidate the difference between angularly constrained and unconstrained overstretching. We propose that the smoothness of the angularly constrained overstretching transition is a consequence of the molecule being in the vicinity of criticality for a broad range of values of applied tension.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20010072133&hterms=surface+temperature+measurement+error&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsurface%2Btemperature%2Bmeasurement%2Berror','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20010072133&hterms=surface+temperature+measurement+error&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsurface%2Btemperature%2Bmeasurement%2Berror"><span id="translatedtitle">Assimilation of Combined Microwave and Lightning Measurement in a <span class="hlt">Mesoscale</span> Weather Prediction <span class="hlt">Model</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, Dong-Eon; Weinman, James A.; Busalacchi, Antonio J. (Technical Monitor)</p> <p>2000-01-01</p> <p>Intermittent measurements of precipitation and integrated water vapor (IWV) distributions were retrieved from the Special Sensor Microwave/Imager (SSM/I) and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) radiometers. Lightning generates very low frequency (VLF) radio noise pulses called sferics. Those pulses propagate over large distances so that they can be continuously monitored with a sparse network of ground based radio receivers. Sferics data, tuned with intermittent spaceborne microwave radiometer data, were used to generate estimated rainfall that was assimilated into a <span class="hlt">mesoscale</span> weather prediction <span class="hlt">model</span>. Both continuous latent heating adjustment and a variational technique are applied as assimilation procedures to evaluate the impact of lightning observations on the forecast of an intense winter squall line over the Gulf of Mexico. Sensitivities to the assimilation of additional measurements such as IWV and sea surface temperature (SST), and measurement errors will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA43C..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA43C..07C"><span id="translatedtitle">The <span class="hlt">Mesoscale</span> Ionospheric Simulation Testbed (MIST) Regional Data Assimilation <span class="hlt">Model</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Comberiate, J.; Kelly, M. A.; Miller, E.; Paxton, L.</p> <p>2013-12-01</p> <p>The <span class="hlt">Mesoscale</span> Ionospheric Simulation Testbed (MIST) provides a regional nowcast and forecast of electron density values and has sufficient resolution to include equatorial plasma bubbles. The SSUSI instrument on the DMSP F18 satellite has high-resolution nightly observations of plasma bubbles at 8 PM local time throughout the current solar maximum. MIST can assimilate SSUSI UV observations, GPS TEC measurements, and SCINDA S4 readings simultaneously into a single scintillation map over a region of interest. MIST also <span class="hlt">models</span> ionospheric physics to provide a short-term UHF scintillation forecast based on assimilated data. We will present examples of electron density and scintillation maps from MIST. We will also discuss the potential to predict scintillation occurrence up to 6 hours in advance using observations of the equatorial arcs from SSUSI observations at 5:30 PM local time on the DMSP F17 satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005BAMS...86..961D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005BAMS...86..961D"><span id="translatedtitle">Multifunctional <span class="hlt">Mesoscale</span> Observing Networks.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dabberdt, Walter F.; Schlatter, Thomas W.; Carr, Frederick H.; Friday, Elbert W. Joe; Jorgensen, David; Koch, Steven; Pirone, Maria; Ralph, F. Martin; Sun, Juanzhen; Welsh, Patrick; Wilson, James W.; Zou, Xiaolei</p> <p>2005-07-01</p> <p>More than 120 scientists, engineers, administrators, and users met on 8 10 December 2003 in a workshop format to discuss the needs for enhanced three-dimensional <span class="hlt">mesoscale</span> observing networks. Improved networks are seen as being critical to advancing numerical and empirical <span class="hlt">modeling</span> for a variety of <span class="hlt">mesoscale</span> applications, including severe weather warnings and forecasts, hydrology, air-quality forecasting, chemical emergency response, transportation safety, energy management, and others. The participants shared a clear and common vision for the observing requirements: existing two-dimensional <span class="hlt">mesoscale</span> measurement networks do not provide observations of the type, frequency, and density that are required to optimize <span class="hlt">mesoscale</span> prediction and nowcasts. To be viable, <span class="hlt">mesoscale</span> observing networks must serve multiple applications, and the public, private, and academic sectors must all actively participate in their design and implementation, as well as in the creation and delivery of value-added products. The <span class="hlt">mesoscale</span> measurement challenge can best be met by an integrated approach that considers all elements of an end-to-end solution—identifying end users and their needs, designing an optimal mix of observations, defining the balance between static and dynamic (targeted or adaptive) sampling strategies, establishing long-term test beds, and developing effective implementation strategies. Detailed recommendations are provided pertaining to nowcasting, numerical prediction and data assimilation, test beds, and implementation strategies.<HR ALIGN="center" WIDTH="30%"></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.........3A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.........3A"><span id="translatedtitle"><span class="hlt">Mesoscale</span> <span class="hlt">Modeling</span> of Heterogeneous Materials Systems: From Solid Oxide Fuel Cells to Bulk Metallic Glasses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdeljawad, Fadi F.</p> <p></p> <p>Heterogeneous materials systems hold the key to the future development of a broad range of increasingly complex technological applications. For example, multi-phase and/or multi-component materials are at the forefront research on the development of efficient energy devices, and the future generation of structural materials with optimal mechanical properties. In this dissertation, we focus on two materials systems, namely, solid oxide fuel cells (SOFCs) and bulk metallic glasses (BMGs), where we investigate, through theoretical and <span class="hlt">mesoscale</span> computational <span class="hlt">models</span>, the role of microstructure on the properties of these heterogeneous systems. For the solid oxide fuel cell project, a computational framework is developed to investigate the topological evolution of Ni phase in SOFC porous anodes, and the accompanying changes to a wide range of microstructural attributes that affect electrochemical performance. Additionally, with the aid of this framework, we study the reduction-oxidation instability, mechanical deformation and damage accumulation in SOFC anodes. In particular, the SOFC project is focused on the role of anode microstructure, characterized by particle size and ratio, on the microstructural stability and mechanical durability of SOFC anodes. For the bulk metallic glass project, a <span class="hlt">mesoscale</span> <span class="hlt">model</span> is introduced that accounts for the structural heterogeneity of monolithic BMGs and BMG composites, and captures the fundamental aspects of plastic deformation in such systems. We examine the effect of internal structure, characterized by rigid/soft short range order (SRO), on the deformation behavior of monolithic BMGs, while for BMG composites, we study the role of ductile phase microstructure, particle size, morphology and area fraction, on the mechanical properties and overall ductility of these systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8128N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8128N"><span id="translatedtitle">Streamflow data assimilation for the <span class="hlt">mesoscale</span> hydrologic <span class="hlt">model</span> (mHM) using particle filtering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noh, Seong Jin; Rakovec, Oldrich; Kumar, Rohini; Samaniego, Luis; Choi, Shin-woo</p> <p>2015-04-01</p> <p>Data assimilation has been becoming popular to increase the certainty of the hydrologic prediction considering various sources of uncertainty through the hydrologic <span class="hlt">modeling</span> chain. In this study, we develop a data assimilation framework for the <span class="hlt">mesoscale</span> hydrologic <span class="hlt">model</span> (mHM 5.2, http://www.ufz.de/mhm) using particle filtering, which is a sequential DA method for non-linear and non-Gaussian <span class="hlt">models</span>. The mHM is a grid based distributed <span class="hlt">model</span> that is based on numerical approximations of dominant hydrologic processes having similarity with the HBV and VIC <span class="hlt">models</span>. The developed DA framework for the mHM represents simulation uncertainty by <span class="hlt">model</span> ensembles and updates spatial distributions of <span class="hlt">model</span> state variables when new observations are available in each updating time interval. The evaluation of the proposed method is carried out within several large European basins via assimilating multiple streamflow measurements in a daily interval. Dimensional limitations of particle filtering is resolved by effective noise specification methods, which uses spatial and temporal correlation of weather forcing data to represent <span class="hlt">model</span> structural uncertainty. The presentation will be focused on gains and limitations of streamflow data assimilation in several hindcasting experiments. In addition, impacts of non-Gaussian distributions of state variables on <span class="hlt">model</span> performance will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011HESSD...8.5165B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011HESSD...8.5165B"><span id="translatedtitle">A framework to utilize turbulent flux measurements for <span class="hlt">mesoscale</span> <span class="hlt">models</span> and remote sensing applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babel, W.; Huneke, S.; Foken, T.</p> <p>2011-05-01</p> <p>Meteorologically measured fluxes of energy and matter between the surface and the atmosphere originate from a source area of certain extent, located in the upwind sector of the device. The spatial representativeness of such measurements is strongly influenced by the heterogeneity of the landscape. The footprint concept is capable of linking observed data with spatial heterogeneity. This study aims at upscaling eddy covariance derived fluxes to a grid size of 1 km edge length, which is typical for <span class="hlt">mesoscale</span> <span class="hlt">models</span> or low resolution remote sensing data. Here an upscaling strategy is presented, utilizing footprint <span class="hlt">modelling</span> and SVAT <span class="hlt">modelling</span> as well as observations from a target land-use area. The general idea of this scheme is to <span class="hlt">model</span> fluxes from adjacent land-use types and combine them with the measured flux data to yield a grid representative flux according to the land-use distribution within the grid cell. The performance of the upscaling routine is evaluated with real datasets, which are considered to be land-use specific fluxes in a grid cell. The measurements above rye and maize fields stem from the LITFASS experiment 2003 in Lindenberg, Germany and the respective <span class="hlt">modelled</span> timeseries were derived by the SVAT <span class="hlt">model</span> SEWAB. Contributions from each land-use type to the observations are estimated using a forward lagrangian stochastic <span class="hlt">model</span>. A representation error is defined as the error in flux estimates made when accepting the measurements unchanged as grid representative flux and ignoring flux contributions from other land-use types within the respective grid cell. Results show that this representation error can be reduced up to 56 % when applying the spatial integration. This shows the potential for further application of this strategy, although the absolute differences between flux observations from rye and maize were so small, that the spatial integration would be rejected in a real situation. Corresponding thresholds for this decision have been estimated as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.2729C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.2729C"><span id="translatedtitle">What can we learn from the hydrological <span class="hlt">modeling</span> of small-scale catchments for the discharge and water balance <span class="hlt">modeling</span> of <span class="hlt">mesoscale</span> catchments?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cornelissen, Thomas; Diekkrüger, Bernd; Bogena, Heye</p> <p>2015-04-01</p> <p>The application of 3D hydrological <span class="hlt">models</span> remains a challenge both in research and application studies because the parameterization not only depends on the amount and quality of data available for calibration and validation but also on the spatial and temporal <span class="hlt">model</span> resolution. In recent years, the <span class="hlt">model</span> parameterization has improved with the availability of high resolution data (e.g. eddy-covariance, wireless soil sensor networks). Unfortunately, these high resolution data are typically only available for small scale research test sites. This study aims to upscale the parameterization from a highly equipped, small-scale catchment to a <span class="hlt">mesoscale</span> catchment in order to reduce the parameterization uncertainty at that scale. The two <span class="hlt">nested</span> catchments chosen for the study are the 0.38 km² large spruce covered Wüstebach catchment and the 42 km² large Erkensruhr catchment characterized by a mixture of spruce and beech forest and grassland vegetation. The 3D hydrogeological <span class="hlt">model</span> HydroGeoSphere (HGS) has already been setup for the Wüstebach catchment in a previous study with a focus on the simulation performance of soil water dynamics and patterns. Thus, the parameterization process did not only optimize the water balance components but the catchment's wireless soil sensor network data were utilized to calibrate porosities in order to improve the simulation of soil moisture dynamics. In this study we compared different HGS <span class="hlt">model</span> realizations for the Erkensruhr catchment with different input data. For the first <span class="hlt">model</span> realization, the catchment is treated heterogeneous in terms of soil properties and topography but homogeneous with respect to land use, precipitation and potential evapotranspiration. For this case, the spruce forest parameterization and the climate input data were taken directly from the small-scale Wüstebach <span class="hlt">model</span> realization. Next, the calibrated soil porosity for the Wüstebach catchment is applied to the Erkensruhr. Further <span class="hlt">model</span> realizations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5879503','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5879503"><span id="translatedtitle">MELSAR: a <span class="hlt">mesoscale</span> air quality <span class="hlt">model</span> for complex terrain. Volume 2. Appendices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Allwine, K.J.; Whiteman, C.D.</p> <p>1985-04-01</p> <p>This final report is submitted as part of the Green River Ambient <span class="hlt">Model</span> Assessment (GRAMA) project conducted at the US Department of Energy's Pacific Northwest Laboratory for the US Environmental Protection Agency. The GRAMA Program has, as its ultimate goal, the development of validated air quality <span class="hlt">models</span> that can be applied to the complex terrain of the Green River Formation of western Colorado, eastern Utah and southern Wyoming. The Green River Formation is a geologic formation containing large reserves of oil shale, coal, and other natural resources. Development of these resources may lead to a degradation of the air quality of the region. Air quality <span class="hlt">models</span> are needed immediately for planning and regulatory purposes to assess the magnitude of these regional impacts. This report documents one of the <span class="hlt">models</span> being developed for this purpose within GRAMA - specifically a <span class="hlt">model</span> to predict short averaging time (less than or equal to 24 h) pollutant concentrations resulting from the <span class="hlt">mesoscale</span> transport of pollutant releases from multiple sources. MELSAR has not undergone any rigorous operational testing, sensitivity analyses, or validation studies. Testing and evaluation of the <span class="hlt">model</span> are needed to gain a measure of confidence in the <span class="hlt">model</span>'s performance. This report consists of two volumes. This volume contains the Appendices, which include listings of the FORTRAN code and Volume 1 contains the <span class="hlt">model</span> overview, technical description, and user's guide. 13 figs., 10 tabs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004ACPD....4.5455L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004ACPD....4.5455L&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mesoscale</span> <span class="hlt">modeling</span> of combined aerosol and photo-oxidant processes in the eastern Mediterranean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lazaridis, M.; Spyridaki, A.; Solberg, S.; Smolík, J.; Ždímal, V.; Eleftheriadis, K.; Aleksandropoulou, V.; Hov, O.; Georgopoulos, P. G.</p> <p>2004-09-01</p> <p>Particulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO <span class="hlt">mesoscale</span> air quality <span class="hlt">model</span> in conjunction with the NILU-CTM regional <span class="hlt">model</span>. Meteorological data were obtained from the RAMS prognostic meteorological <span class="hlt">model</span>. The <span class="hlt">modeling</span> domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The <span class="hlt">modeling</span> system is applied to study the atmospheric processes in three periods, i.e. 13-16 July 2000, 26-30 July 2000 and 7-14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The <span class="hlt">modeling</span> results were compared with field data obtained in the same period. Comparison of the <span class="hlt">modeling</span> results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO <span class="hlt">model</span> underestimates the PM10 measured concentrations during summer but better comparison has been obtained for the winter data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015MolPh.113..898M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015MolPh.113..898M&link_type=ABSTRACT"><span id="translatedtitle">Mucin aggregation from a rod-like <span class="hlt">meso-scale</span> <span class="hlt">model</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreno, Nicolas; Perilla, Jairo E.; Colina, Coray M.; Lísal, Martin</p> <p>2015-05-01</p> <p>Dissipative particle dynamics, a <span class="hlt">meso-scale</span> particle-based <span class="hlt">model</span>, was used to study the aggregation of mucins in aqueous solutions. Concentration, strength of the mucin-water interactions, as well as the effects of size, shape, and composition of the <span class="hlt">model</span> molecules were studied. <span class="hlt">Model</span> proteins were represented as rod-like objects formed by coarse-grained beads. In the first <span class="hlt">model</span>, only one type of beads formed the mucin. It was found that all the surfaces were available to form aggregates and the conformation of the aggregates was a function of the strength of the mucin-water interaction. With this <span class="hlt">model</span>, the number of aggregates was unaffected by the initial position of the mucins in the simulation box, except for the lowest mucin concentration. In a more refined mucin <span class="hlt">model</span>, two kinds of beads were used in the molecule in order to represent the existence of cysteine-like terminal groups in the actual molecule. With this new scheme, aggregation took place by the interaction of the terminal groups between <span class="hlt">model</span> molecules. The kinetic analysis of the evolution of the number of aggregates with time was also studied for both mucin <span class="hlt">models</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990PhDT........91H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990PhDT........91H"><span id="translatedtitle">a <span class="hlt">Mesoscale</span> Planetary Boundary Layer Numerical <span class="hlt">Model</span> for Simulations of Topographically Induced Circulations.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Ching-Yuang Albert</p> <p>1990-01-01</p> <p>A <span class="hlt">mesoscale</span> planetary boundary layer (PBL) numerical <span class="hlt">model</span> is developed to investigate airflow over complex topography. The <span class="hlt">model</span> physics includes PBL turbulent transfer, atmospheric longwave and shortwave radiation, diurnal energy budgets over ground, cloud microphysics and subgrid cumulus parameterization. The <span class="hlt">model</span> utilizes a new fourth order Crowley advection scheme which preserves phase and amplitude much better than other Crowley schemes. Turbulence closures using the turbulent kinetic energy (TKE) and dissipation (varepsilon ) equations are investigated with the level 2.5 scheme of Mellor and Yamada (1982) to better determine eddy diffusivities. One-dimensional (1-D) <span class="hlt">model</span> results show that the PBL flows under various stability conditions are not significantly sensitive to the modified Blackadar's and Kolmogorov's eddy mixing length formations, although the latter yields excessively large mixing lengths in the entrainment region of the upper PBL. With the same prognostic TKE equation, the <span class="hlt">model</span> results show insensitivity of the 1-D flow to the details of diagnostic formulations in the closures and to eddy Prandtl numbers. A 2-D <span class="hlt">model</span> is used to stimulate January 28 cold -air outbreak over the Gulf Stream region during the IOP -2 (Intensive Observation Period) of the 1986 Genesis of Atlantic Lows Experiment (GALE). The <span class="hlt">modeled</span> 2-D circulation system is found to be sensitive to Prandtl number, in contrast to the 1-D <span class="hlt">model</span> results. Prandtl number becomes increasingly important as the clouds begin to interact with the marine boundary layer (MBL). Using the E-varepsilon closure, the <span class="hlt">model</span> predicts the observed MBL structure that includes a low level jet west of the Gulf Stream warm core and a constrained boundary layer height due to the middle-level stable layer. Two cases with 3-D idealized flow are also simulated for the same GALE IOP. For the easterly onshore ambient flow, a confluence zone appears near the coastline in response to the strong oceanic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002902','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002902"><span id="translatedtitle">High-Resolution <span class="hlt">Mesoscale</span> <span class="hlt">Model</span> Setup for the Eastern Range and Wallops Flight Facility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Watson, Leela R.; Zavodsky, Bradley T.</p> <p>2015-01-01</p> <p><span class="hlt">Mesoscale</span> weather conditions can have an adverse effect on space launch, landing, ground processing, and weather advisories, watches, and warnings at the Eastern Range (ER) in Florida and Wallops Flight Facility (WFF) in Virginia. During summer, land-sea interactions across Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) lead to sea breeze front formation, which can spawn deep convection that can hinder operations and endanger personnel and resources. Many other weak locally-driven low-level boundaries and their interactions with the sea breeze front and each other can also initiate deep convection in the KSC/CCAFS area. These convective processes often last 60 minutes or less and pose a significant challenge to the local forecasters. Surface winds during the transition seasons (spring and fall) pose the most difficulties for the forecasters at WFF. They also encounter problems forecasting convective activity and temperature during those seasons. Therefore, accurate <span class="hlt">mesoscale</span> <span class="hlt">model</span> forecasts are needed to better forecast a variety of unique weather phenomena. Global and national scale <span class="hlt">models</span> cannot properly resolve important local-scale weather features at each location due to their horizontal resolutions being much too coarse. Therefore, a properly tuned local data assimilation (DA) and forecast <span class="hlt">model</span> at a high resolution is needed to provide improved capability. To accomplish this, a number of sensitivity tests were performed using the Weather Research and Forecasting (WRF) <span class="hlt">model</span> in order to determine the best DA/<span class="hlt">model</span> configuration for operational use at each of the space launch ranges to best predict winds, precipitation, and temperature. A set of Perl scripts to run the Gridpoint Statistical Interpolation (GSI)/WRF in real-time were provided by NASA's Short-term Prediction Research and Transition Center (SPoRT). The GSI can analyze many types of observational data including satellite, radar, and conventional data. The GSI/WRF scripts</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713593K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713593K"><span id="translatedtitle">Investigation of flow transition problems at WRFs <span class="hlt">nested</span>-domain interfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirkil, Gokhan</p> <p>2015-04-01</p> <p>Many contemporary atmospheric simulation <span class="hlt">models</span> employ a grid <span class="hlt">nesting</span> capability that permits large-eddy simulations (LES) to be conducted over subsets of larger bounding simulations, with the bounding-domain solutions providing lateral boundary conditions for the <span class="hlt">nested</span> domains within. While grid <span class="hlt">nesting</span> has been successfully applied at GCM to <span class="hlt">mesoscale</span> resolutions, such <span class="hlt">nesting</span> behavior at higher resolutions, including those appropriate for LES, is less well understood. We investigate such grid <span class="hlt">nesting</span> capabilities for conducting an LES inside both larger-scale LES and <span class="hlt">mesoscale</span> simulations using the Weather Research and Forecasting (WRF) <span class="hlt">model</span>. Comparisons among the velocity and stress profiles inside the <span class="hlt">nested</span> domain relative to both the outer domain and non-<span class="hlt">nested</span> simulations indicate that errors contributed from the bounding domains are observed within the <span class="hlt">nested</span>-domain solution. We also examine the spatial scales required for flow structures to equilibrate to the finer mesh as flow enters a <span class="hlt">nest</span>, and how equilibration depends on several parameters, including mesh resolution and the type of turbulence subfilter-scale stress <span class="hlt">model</span> used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17500628','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17500628"><span id="translatedtitle"><span class="hlt">Nested</span> incremental <span class="hlt">modeling</span> in the development of computational theories: the CDP+ <span class="hlt">model</span> of reading aloud.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Perry, Conrad; Ziegler, Johannes C; Zorzi, Marco</p> <p>2007-04-01</p> <p>At least 3 different types of computational <span class="hlt">model</span> have been shown to account for various facets of both normal and impaired single word reading: (a) the connectionist triangle <span class="hlt">model</span>, (b) the dual-route cascaded <span class="hlt">model</span>, and (c) the connectionist dual process <span class="hlt">model</span>. Major strengths and weaknesses of these <span class="hlt">models</span> are identified. In the spirit of <span class="hlt">nested</span> incremental <span class="hlt">modeling</span>, a new connectionist dual process <span class="hlt">model</span> (the CDP+ <span class="hlt">model</span>) is presented. This <span class="hlt">model</span> builds on the strengths of 2 of the previous <span class="hlt">models</span> while eliminating their weaknesses. Contrary to the dual-route cascaded <span class="hlt">model</span>, CDP+ is able to learn and produce graded consistency effects. Contrary to the triangle and the connectionist dual process <span class="hlt">models</span>, CDP+ accounts for serial effects and has more accurate nonword reading performance. CDP+ also beats all previous <span class="hlt">models</span> by an order of magnitude when predicting individual item-level variance on large databases. Thus, the authors show that building on existing theories by combining the best features of previous <span class="hlt">models</span>--a <span class="hlt">nested</span> <span class="hlt">modeling</span> strategy that is commonly used in other areas of science but often neglected in psychology--results in better and more powerful computational <span class="hlt">models</span>. PMID:17500628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=234244&keyword=Winds&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=64993251&CFTOKEN=39643336','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=234244&keyword=Winds&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=64993251&CFTOKEN=39643336"><span id="translatedtitle">Examining Interior Grid Nudging Techniques Using Two-Way <span class="hlt">Nesting</span> in the WRF <span class="hlt">Model</span> for Regional Climate <span class="hlt">Modeling</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>This study evaluates interior nudging techniques using the Weather Research and Forecasting (WRF) <span class="hlt">model</span> for regional climate <span class="hlt">modeling</span> over the conterminous United States (CONUS) using a two-way <span class="hlt">nested</span> configuration. NCEP–Department of Energy Atmospheric <span class="hlt">Model</span> Intercomparison Pro...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000384','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000384"><span id="translatedtitle">Range-Specific High-Resolution <span class="hlt">Mesoscale</span> <span class="hlt">Model</span> Setup: Data Assimilation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Watson, Leela R.</p> <p>2014-01-01</p> <p><span class="hlt">Mesoscale</span> weather conditions can have an adverse effect on space launch, landing, and ground processing at the Eastern Range (ER) in Florida and Wallops Flight Facility (WFF) in Virginia. During summer, land-sea interactions across Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) lead to sea breeze front formation, which can spawn deep convection that can hinder operations and endanger personnel and resources. Many other weak locally driven low-level boundaries and their interactions with the sea breeze front and each other can also initiate deep convection in the KSC/CCAFS area. Some of these other boundaries include the Indian River breeze front, Banana River breeze front, outflows from previous convection, horizontal convective rolls, convergence lines from other inland bodies of water such as Lake Okeechobee, the trailing convergence line from convergence of sea breeze fronts due to the shape of Cape Canaveral, frictional convergence lines from the islands in the Bahamas, convergence lines from soil moisture differences, convergence lines from cloud shading, and others. All these subtle weak boundary interactions often make forecasting of operationally important weather very difficult at KSC/CCAFS during the convective season (May-Oct). These convective processes often build quickly, last a short time (60 minutes or less), and occur over small distances, all of which also poses a significant challenge to the local forecasters who are responsible for issuing weather advisories, watches, and warnings. Surface winds during the transition seasons of spring and fall pose the most difficulties for the forecasters at WFF. They also encounter problems forecasting convective activity and temperature during those seasons. Therefore, accurate <span class="hlt">mesoscale</span> <span class="hlt">model</span> forecasts are needed to aid in their decision making. Both the ER and WFF would benefit greatly from high-resolution <span class="hlt">mesoscale</span> <span class="hlt">model</span> output to better forecast a variety of unique weather</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010ACPD...1025909F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010ACPD...1025909F&link_type=ABSTRACT"><span id="translatedtitle">Sensitivity of <span class="hlt">mesoscale</span> <span class="hlt">model</span> urban boundary layer meteorology to urban morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flagg, D. D.; Taylor, P. A.</p> <p>2010-11-01</p> <p><span class="hlt">Mesoscale</span> <span class="hlt">modeling</span> of the urban boundary layer requires careful parameterization of the surface due to its heterogeneous morphology. <span class="hlt">Model</span> estimated meteorological quantities, including the surface energy budget and canopy layer variables, will respond accordingly to the scale of representation. This study examines the sensitivity of the surface energy balance, canopy layer and boundary layer meteorology to the scale of urban surface representation in a real urban area (Detroit-Windsor (USA-Canada)) during several dry, cloud-free summer periods. The <span class="hlt">model</span> used is the Weather Research and Forecasting (WRF) <span class="hlt">model</span> with its coupled single-layer urban canopy <span class="hlt">model</span>. Some <span class="hlt">model</span> verification is presented using measurements from the Border Air Quality and Meteorology Study (BAQS-Met) 2007 field campaign and additional sources. Case studies span from "neighborhood" (10 s ~ 30 m) to very coarse (120 s ~ 3.7 km) resolution. Small changes in scale can affect the classification of the surface, affecting both the local and grid-average meteorology. Results indicate high sensitivity in turbulent latent heat flux from the natural surface and sensible heat flux from the urban canopy. Small scale change is also shown to delay timing of a lake-breeze front passage and can affect the timing of local transition in static stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ACP....11.2951F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ACP....11.2951F&link_type=ABSTRACT"><span id="translatedtitle">Sensitivity of <span class="hlt">mesoscale</span> <span class="hlt">model</span> urban boundary layer meteorology to the scale of urban representation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flagg, D. D.; Taylor, P. A.</p> <p>2011-03-01</p> <p><span class="hlt">Mesoscale</span> <span class="hlt">modeling</span> of the urban boundary layer requires careful parameterization of the surface due to its heterogeneous morphology. <span class="hlt">Model</span> estimated meteorological quantities, including the surface energy budget and canopy layer variables, will respond accordingly to the scale of representation. This study examines the sensitivity of the surface energy balance, canopy layer and boundary layer meteorology to the scale of urban surface representation in a real urban area (Detroit-Windsor (USA-Canada)) during several dry, cloud-free summer periods. The <span class="hlt">model</span> used is the Weather Research and Forecasting (WRF) <span class="hlt">model</span> with its coupled single-layer urban canopy <span class="hlt">model</span>. Some <span class="hlt">model</span> verification is presented using measurements from the Border Air Quality and Meteorology Study (BAQS-Met) 2007 field campaign and additional sources. Case studies span from "neighborhood" (10 s ~308 m) to very coarse (120 s ~3.7 km) resolution. Small changes in scale can affect the classification of the surface, affecting both the local and grid-average meteorology. Results indicate high sensitivity in turbulent latent heat flux from the natural surface and sensible heat flux from the urban canopy. Small scale change is also shown to delay timing of a lake-breeze front passage and can affect the timing of local transition in static stability.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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