Ozone in the marine boundary layer of Bay of Bengal during post-winter period: Spatial pattern and role of meteorology

Ozone measurements were carried out in the marine environment of the Bay of Bengal during the post-winter months of March–April 2006, as part of the Integrated Campaign for Aerosols, gases and Radiation Budget. The ozone mixing ratio was found to be high over the northern/head BoB with a mean value of 27 ± 3 ppb and minimum over the mid-BoB with 12 ± 3 ppb. The spatial distribution was closely associated with the airflow pattern, airmass back trajectories and the boundary layer height. In this marine environment, meteorology, in particular, the water vapour content also played a significant role in governing the diurnal pattern of ozone in addition to photochemistry. Vertical transport is also partially responsible for the high ozone over the head BoB. The diurnal patterns were simulated using the chemical box model. The spatial map of marine boundary layer ozone was compared with that of tropospheric column ozone, NO2 and CO.