HR: 1340h
AN: A23C-1481    [Abstracts]
TI: Diagnosing MM5-CMAQ Performance for the Summer 2000 Central California Ozone Study
AU: * Brown, N J
EM: njbrown@lbl.gov
AF: Atmospheric Science Department, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
AU: Jin, L
AF: Atmospheric Science Department, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
AU: Tonse, S
AF: Atmospheric Science Department, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
AU: Harley, R A
AF: Department of Civil and Environmental Engineering, Unversity of California at Berkeley, Berkeley, CA 94720, United States
AU: Bao, J
AF: Regional Weather and Climate Applications Division, NOAA/Environmental Technology Laboratory 325 Broadway, Mail Stop: ET7, Boulder, CO 80305, United States
AU: Michelson, S A
AF: Regional Weather and Climate Applications Division, NOAA/Environmental Technology Laboratory 325 Broadway, Mail Stop: ET7, Boulder, CO 80305, United States
AU: Wilczak, J
AF: Regional Weather and Climate Applications Division, NOAA/Environmental Technology Laboratory 325 Broadway, Mail Stop: ET7, Boulder, CO 80305, United States
AB: Past evaluations of the Community Multiscale Air Quality (CMAQ) modeling system have focused on the eastern United States and applications of it are usually conducted for high ozone episodes that last for a few days. In our research, we seek more comprehensive model evaluation by applying MM5-CMAQ to simulating ozone formation for an entire summer season in central California, where ozone air pollution problems are severe and air districts are out of compliance with the 8-hour ozone standard. In this paper, we have simulated ozone formation in the central California region with CMAQv4.6 for a 15-day period, which includes a five-day high ozone episode. Simulated ozone concentrations adequately match the observed patterns, except in the Bay area during the last 5-day period. Model performance does not degrade over time, but exhibits spatial trends in biases. CMAQ tends to over-predict ozone at coastal areas, and slightly under- predict it in the central valley. Wind field nudging greatly improves the chemical transport processes. When transport errors are minimized, we see similar ozone sensitivities when comparing observed and modeled ozone production efficiencies. Sensitivity analysis is performed and the most influential factors studied here are listed for different geographical regions. The Bay area is sensitive to uncertainties in all the input parameters considered here, which suggests greater challenges on correct simulating ozone concentrations in this area.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting