Changes in surface ozone levels due to convective downdrafts over the Bay of Bengal

Abstract

Simultaneous measurements of surface level ozone (O3) and meteorological parameters were made over the Bay of Bengal (BOB) during a cruise between 14 September and 12 October 2002. Variations in surface O3, equivalent potential temperature (θE) and associated meteorological parameters clearly show evidence of convective downdrafts during 18-19 September and 25-26 September. Sharp increase in O3 mixing ratio is coupled with decrease in θE value in the detrained air. The vertical wind velocity and satellite images also indicate significant convective activities during these periods. The maximum changes in O3 and θE were 26 ppbv and 12 K, respectively. These events comprise of both short and long time scale downdrafts. Copyright 2006 by the American Geophysical Union.