Measurement of air-sea fluxes over the Indian Ocean and the Bay of Bengal

Atmospheric and oceanic data were collected in 1998 and 1999 over the tropical Indian Ocean during three cruises of the Indian research vessel Sagar Kanya, covering different geographic locations and seasons, including boreal winter, peak monsoon, and postmonsoon periods. The present study is mainly based on the measurements made during the three cruises. It is found that there are important differences in the near-surface characteristics during monsoon and other seasons. The largest variations in the net surface heat flux occurred during the monsoon period. The specific humidity difference between sea surface and air at 10-m height shows a strong seasonal dependence, with the lowest values observed during the monsoon period. An important finding from the ship observations is that, at a given SST, the surface air over the Indian Ocean is much warmer compared to that over other tropical oceans and the west Pacific warm pool in particular. These findings are supported by data obtained by a moored buoy in the north Indian Ocean and also from the Comprehensive Ocean-Atmosphere Data Set for the Indian Ocean.