Long-term variation of bromine monoxide in India from GOME and SCIAMACHY instruments

The production of bromine monoxide (BrO) from seawater and its influence in catalytically depleting stratospheric and boundary layer ozone at high latitudes have been well established. In India the study of BrO has so far been limited to relatively short-term measurements, even though the Indian mainland has a coastline of length 6100 km and is surrounded by the Arabian Sea, the Indian Ocean and the Bay of Bengal, all probable major sources of BrO. In this study the variation in BrO vertical column density (VCD) was examined using data derived from Global Ozone Monitoring Experiment (GOME) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instruments for the period from 1996 to 2008. BrO columns in India are found to be anticorrelated with total ozone column, increase with an increase in latitude, display a small interannual and seasonal variation, and an increasing trend over the Arabian Sea, Ahmedabad and Chennai, a mixed trend over the Bay of Bengal, the Indian Ocean, Jharia and Kolkata and a decreasing trend at New Delhi and Kanpur.