P36  Impact of Meteorology Downscaling to the Regional Air Quality Simulation, using WRF/CMAQ Modeling System

Kim, Hyun Cheol, National Oceanic and Atmospheric Administration/ARL, Songyou Hong, Yonsei University, Fantine Ngan, and Pius Lee, NOAA/ARL

We investigated the impacts of meteorology downscaling in regional air quality simulation. Multiple global (or semi-global) meteorology simulations have been utilized to initiate regional meteorology simulations, and their impacts on regional air quality simulations are studied. Weather Research and Forecasting (WRF) modeling system is used to simulated regional meteorology using initializations from North American Mesoscale Model (NAM), Global Forecast System (GFS), and Global/Regional Integrated Model system (GRIMs), and Community Multi-scale Air Quality/Sparse Matrix Operator Kernel Emission (CMAQ/SMOKE) modeling system is used to simulated regional air quality. Impacts of meteorological variables (e.g. surface temperature, wind speed,  boundary layer, precipitation, and frontal activities) on forecast pollutant concentrations were investigated using surface observations from numerous observational sources, including the Meteorological Assimilation Data Ingest System (MADIS), the EPA AirNOW/AQS, the Interagency Monitoring of Protected Visual Environments (IMPROVE), and Continuous Ambient Monitoring Stations (CAMS). Results show that the variance of key meteorological parameters, such as synoptic wind patterns and surface temperature, have strong correlation with a pollutantŐs variation and the modelŐs forecast performance (e.g. ozone bias). We present how the differences in frontal passage location and timing affect production and removal of regional air pollutants. For the eastern US, locations of surface temperature bias are also well associated with surface ozone bias, implying potential explanation for the surface ozone bias during summertime in this region. Analysis of multi-year trend revealed a one-degree change of surface temperature was associated with up to 10% increase of afternoon ozone.