Trends in tropical tropospheric column ozone from satellite data and MOZART model

Abstract

Trend analysis of tropical (30° S-30° N) tropospheric columnar ozone (TCO) has been done using Nimbus7 and Earth Probe satellite -Total Ozone Mapping Spectrometer (TOMS) data for the period of 1979-2005 using multifunctional regression model. Results indicate highest increasing trend (7-9% per decade) over some parts of south Asian continental region which is attributed to increasingly high emissions of ozone precursors over the region. Among different marine regions, Ozone trend is found to be highest (4-6% per decade) over the Bay of Bengal which is largely be explained by the large scale wind systems causing massive transport of continental pollutants over this region. The study also includes the comparison of the satellite results with those obtained from a 3-D chemistry transport model. In some cases, the magnitude of observed trends is consistent with the model trends. However, in some cases like East Asia and area around Philippines differences are inevitable.