Multiscale Comparison of Air Quality Modeling for the 1996 Paso Del Norte Ozone event
Duanjun Lu, Jackson State University, Jackson, MS; and R. S. Reddy, D. R. M. Fitzgerald, W. R. Stockwell, Q. L. Williams, and P. B. Tchounwou
Many studies have investigated model performance at the spatial resolution of less than 10 km, there is relatively limited information available for showing what spatial resolution is needed to successfully capture the high ozone event with an acceptable accuracy of central strength and sufficiently detail information of structural distribution. In this study, an air quality modeling system including chemistry and transport model, CMAQ, emission processing model, SMOKE and mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of 1996 Paso del Norte Ozone Campaign. The results show that grid resolution evidently influences the simulations of ozone formation, dispersion, transportation and structural distribution. The 36 km, 12 km, 4 km and 1 km models captured the diurnal variation of surface ozone. But there were a few hours lag for simulated peak ozone. The coarser the spatial resolution of model, the more the lag of peak ozone occurs. All models underpredicted the peak ozone concentration where the 1 km model produced the best while 36 km model yielded the worst. The problems of maximum ozone underprediction and minimum ozone overprediction can be mitigated by increasing the spatial resolution of model. Compared to fine models, coarse models provided rather simple and smooth structures with many detailed and complex structures lost. The frequency distribution analysis revealed that the high ozone event can hardly be captured by using coarse spatial resolution models, and the high resolution model (grid spacing is no greater than 4 km) is necessary.
Session 2, Field, laboratory, and modeling studies of air quality—II
Monday, 12 January 2009, 1:30 PM-2:30 PM, Room 127A
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