This study has been carried out to analyze the sensitivity of pollutants concentrations over North-East Asia by employing different options of both cumulus parameterization schemes (CPSs) and microphysics schemes. Meteorological model MM5 and air quality model CMAQ were employed and the sensitivity tests of CPSs and microphysics were performed for long-range transport case of higher ozone and PM10. Employed CPSs are Betts-Miller(BM), Grell(GR), Kain-Fritsch2 (KF2), Anthes-Kuo(AK), None scheme, and four microphysics used here are Simple ice, Reisner1, Reisner2, Schultz scheme in MM5. Four cases of high ozone and PM10 long range transportation case were selected in this study based on the observed concentrations and backward trajectory model results. The results showed that horizontal distributions of ensemble mean precipitation yielded acceptable results. Of the all options, GR and Resiner-2 showed relatively good and stable variations for both O3 and PM10 against ensemble mean values. The resultant pollutant concentrations simulated from various CPSs and microphysics schemes indicated maximum 10% and 40% differences on the average for O3 and PM10, respectively.
For O3 case, both CPS and microphysics schemes showed that the difference of precipitation arising from different parameterization schemes was significant by itself, but the resultant ozone variations showed only marginal. However, it is noted that cloud fraction differences played more important role than precipitation in controlling O3 concentrations. The calculated correlation coefficients between cloud fraction vs. ozone variations showed strong negative, while precipitation vs. ozone variations showed relatively lower. This is mainly associated with the difference of photochemical reactions for gas phase O3 generation processes, rather than ozone removal processes by wet deposition.
For PM10 case, sensitivity tests of both CPSs and microphysics showed overall relatively lower correlation coefficients than O3 case. CPS and microphysics tests showed that only precipitation difference gave rise to detectable (but not significant) PM10 difference, reflecting the existence of distinct precipitation band. However cloud fraction essentially derived negligible changes to PM10 concentrations in general, implying that PM10 variation can be traced to number of assumptions made in the model. In this study, weak precipitation intensity cases was primarily selected, focusing on high and long-ranged transported air pollutant cases, indicating that further sensitivity tests of more diverse cases will be required.