Asymmetrical Behavior of the Arabian Sea and Bay of Bengal

The Arabian Sea (AS) and the Bay of Bengal (BB) are located in the north part of the Indian Ocean with similar geographical and meteorological features. Despite this, the two basins have significant differences. Using various satellite data sets, this study investigates the asymmetrical environment of the AS and BB in terms of sea surface salinity (SSS) and rainfall circulation in the two basins. It is observed that the surface salinity in the AS steadily raises northward – the annual mean rises from 35 psu (at the equator) to 36.5 psu (at north of 23° N). The BB, on the contrary, has a high surface salinity in the equatorial region, with salinity decreasing northward – the annual mean drops from 34 psu (at the equator) to 29 psu (in the northern bay), which is roughly 6 psu fresher than the northern AS. There is also a considerable disparity in rainfall distribution between the two basins. The BB is estimated to have a low rainfall pattern in the equatorial span, with rainfall increasing northward - the yearly increase from 7 mm/day at the equator to around 12 mm/day in the northern bay, which is approximately 11 mm/day more than in the northern AS.