Satellite measurements of tropospheric column O3 and NO2 in eastern and southeastern Asia:: Comparison with a global model (MOZART-2)

Satellite measurements of tropospheric column O(3) and NO(2) in eastern and southeastern Asia are analyzed to study the spatial and seasonal characteristics of pollution in these regions. Tropospheric column O(3) is derived from differential measurements of total column ozone from Total Ozone Mapping Spectrometer (TOMS), and stratospheric column ozone from the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS). The tropospheric column NO(2) is measured by Global Ozone Monitoring Experiment (GOME). A global chemical and transport model (Model of Ozone and Related Chemical Tracers, version 2; MOZART-2) is applied to analyze and interpret the satellite measurements. The study, which is based on spring, summer, and fall months of 1997 shows generally good agreement between the model and satellite data with respect to seasonal and spatial characteristics of O(3) and NO(2) fields. The analysis of the model results show that the industrial emission of NO(x) (NO+NO(2)) contributes about 50%-80% to tropospheric column NO(2) in eastern Asia and about 20%-50% in southeastern Asia. The contribution of industrial emission of NO(x) to tropospheric column O(3) ranges from 10% to 30% in eastern Asia. Biomass burning and lightning NO(x) emissions have a small effect on tropospheric O(3) in central and eastern Asia, but they have a significant impact in southeastern Asia. The varying effects of NO(x) on tropospheric column ozone are attributed to differences in relative abundance of volatile organic compounds (VOCs) with respect to total nitrogen in the two regions.