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Analyzing the Effects of Horizontal Resolution on Long-Term Coupled WRF-CMAQ Simulations
Citation:
Gan, M., C. Hogrefe, J. Xing, R. Gilliam, David-C Wong, Jon Pleim, R. Mathur, AND C. Wei. Analyzing the Effects of Horizontal Resolution on Long-Term Coupled WRF-CMAQ Simulations. AWMA Conference, Raleigh, NC, June 22 - 25, 2015.
Impact/Purpose:
The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment. AMAD’s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation’s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
The objective of this study is to determine the adequacy of using a relatively coarse horizontal resolution (i.e. 36 km) to simulate long-term trends of pollutant concentrations and radiation variables with the coupled WRF-CMAQ model. To this end, WRF-CMAQ simulations over the continental U.S. are performed for multiple years during the 1990 -2010 time period at two different horizontal resolutions of 12 and 36 km. Both simulations used the same emission inventory and model configurations. The results show that the 36 km and 12 km simulations are comparable in term of trends analysis for both pollutant concentrations and radiation variables. The advantage of using the coarser 36 km resolution is a significant reduction of computational cost and time which is a key consideration when performing multiple years of simulations for trend analysis. However, if the simulation is used for regional or local air quality analysis, finer horizontal resolution may be beneficial since it can provide information on local gradients. For example, there are minor divergences of both simulations found in the urban, complex terrain and coast regions. Both simulations will be compared to observations and their performance will be assessed. These results will be presented in the poster.
