Mesoscale Meteorological Models

Evaluation of the suitability of mesoscale NWP models for use in dispersion modeling is based on following criteria  

OMEGA Science Application International Corporation (SAIC) 

HOTMAC Yamada Science and Art (YSA) Corporation, New Mexico WRF NCAR, NOAA, DOD, and a consortium of universities 

MM5 is a multiscale (10-1000 km) weather prediction system consisting of data analysis and initialization, dynamical prediction, and postprediction diagnosis and verification codes. The MM5 model (Grell et al. 1994) system source codes and documentation are in the public domain (i.e., the Internet) for use by any person. The MM5 model has demonstrated high skill in mesoscale simulation of tropical cyclone-orography interaction (Wu et al. 1999) as well as various mesoscale 

The results of six real-data case studies are presented here. The case studies considered conditions including dry-line perturbations, tranquil conditions, weak disturbances with light precipitation, mild synoptic forcing, and severe weather environment. The full physics and nonhydrostatic version of MM5 was used in the case studies. The six cases were as follows  

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R. A. P Ake, Mesoscale Meteorological Modeling AcAeimc Press, Orlando, Pla., 1984. 

Brown, M.J., and Williams, M.D. (1998) An Urban Canopy Parameterization for Mesoscale Meteorological Models. Los Alamos National Laboratory, Report LA-UR-98-3831. 

Pielke, R.A. (1984) Mesoscale meteorological modelling, Academic Press. 

More often, three-dimensional gridded meteorological forecast data provided by mesoscale meteorological models such as MM5 will be available. The resolution of the grid will typically be on the order of 1 km, which is too large to capture microscale surface features. Mesoscale model results can be coupled with fine-scale models by enforcing conservation of mass to provide enhanced fine-scale detail. 

CFD-based models use high-resolution grids to develop a detailed representation of the wind field and are typically used to investigate wind fields within urban (obstacle-rich) environments. The models incorporate detailed representations of each obstacle in the environment and provide the only possible approach to the computation of flows deep within urban canyons (a capability not offered by mesoscale meteorological models). A recent field study of dispersion in New York City provided... 

Our studies show that the MM5/11P. C conjugation can provide useful prediction of airborne transport of hazardous materials near the surface. It also demonstrates that the accuracy of HPAC computation strongly depends on the performance of MM5. The forecast skill of mesoscale models is likely to be a function of weather scenarios and the terrain over which the models are being run. Because the numerical techniques are different and the model physics (e.g., PBL, surface, and moist processes) vary considerably among different mesoscale meteorological models, we anticipate that there would be discrepancies between the predictions of individual models. 

Pielke, R.A., 2001. Mesoscale Meteorological Modeling, 2nd ed.. Academic Press, New York. Pielke, R.A. and Pearce, R.P., 1994. Mesoscale Modeling of the Atmosphere, American Mete-... 

Daggupaty, S. M., Tangirala, R. S., andSahota, H. (1994). BLFMESO— A 3-dimensional mesoscale meteorological model for microcomputers, BoMwctary Layer Mefero/. 71, 81-107. 

Pielke, R. A. (2000). Mesoscale Meteorological Modeling, 2nd ed.. Academic Press, New York. 

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