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A YEAR-LONG MM5 EVALUATION USING A MODEL EVALUATION TOOLKIT
Citation:
Gilliam, R, P. Bhave, J E. Pleim, AND T L. Otte. A YEAR-LONG MM5 EVALUATION USING A MODEL EVALUATION TOOLKIT. Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18-20, 2004.
Impact/Purpose:
The objectives of this task are to continuously develop and improve EPA's mesoscale (regional through urban scale) air quality simulation models, such as the Community Multiscale Air Quality (CMAQ) model, as air quality management and NAAQS implementation tools. CMAQ is a multiscale and multi-pollutant chemistry-transport model (CTM) that includes the necessary critical science process modules for atmospheric transport, deposition, cloud mixing, emissions, gas- and aqueous-phase chemical transformation processes, and aerosol dynamics and chemistry. To achieve the advances in CMAQ, research will be conducted to develop and test appropriate chemical and physical mechanisms, improve the accuracy of emissions and dry deposition algorithms, and to develop and improve state-of-the-science meteorology models and contributing process parameterizations.
Description:
Air quality modeling has expanded in both sophistication and application over the past decade. Meteorological and air quality modeling tools are being used for research, forecasting, and regulatory related emission control strategies. Results from air quality simulations have far reaching implications and are closely linked to the meteorological model that drives chemical transport, diffusion, and reactions. Therefore, modeling systems should be evaluated by considering all components involved (Hogrefe et al. 2001). This connection can be achieved by linking the statistical analysis of the air quality model with that of the meteorological model in space and time, in order to distinguish how errors in the air chemistry model are attributed to errors in the meteorological modeling.
An evaluation tool is being developed that will 1) provide a better sense of meteorological model uncertainty; 2) standardize the evaluation process; 3) manage a large volume of evaluation results; 4) make the overall evaluation process more efficient and less labor intensive; and 5) directly link the meteorological model evaluation with the air quality model evaluation.
This study applies the model evaluation tool to a year-long simulation using the Pennsylvania State University (PSU)/National Center for Atmospheric Research (NCAR) fifth-generation mesoscale model (MM5). The results are reported not only to examine the MM5 model performance, but also to demonstrate the effectiveness of the evaluation system. Among the evaluations presented are surface-based 2m temperature, 10m wind, 2m mixing ratio, precipitation and solar radiation. Wind profiler data are also used to examine the ability of MM5 to simulate the vertical distribution of wind over the diurnal cycle. Additionally, a direct linkage between the meteorological and the air quality model performance, specifically ozone and nitrate, is attempted. Only a brief summary of the results are presented here because of manuscript length requirements.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW 13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.