A STUDY ON THE VARIATION OF LATENT-HEAT FLUX OVER THE ARABIAN SEA ANDTHE BAY OF BENGAL BASED ON SATELLITE DATA

Using the 1988 data of ocean surface wind speed and atmospheric water vapour obtained from special sensor microwave/imager (SSM/I) of the De fence Meteorological Satellite Programme (DMSP) of the USA and of sea surface temperature obtained from advanced very high resolution radiom eter (AVHRR) of NOAA, a study on the variation of monthly mean latent heat flux over the Arabian Sea and the Bay of Bengal has been carried out. The surface level humidity has been obtained from the relation de veloped by Liu [Liu W T, Mon Weather Rev (USA), 114 (1986) 1591] with precipitable water. The evaporation has been computed using Bulk param etrization formula. The study shows that the latent heat flux exhibits semi-annual oscillation. It attains the peak just before the onset of the monsoon and reaches the lower values during the active phase of t he monsoon. After the summer monsoon season, it is found to be increas ing. Short-period oscillations are found to be dominant over the Bay o f Bengal. The positions of its maximum and minimum change with season. The potential of passive microwave radiometers to monitor its variabi lity over oceans, which may be useful to several coupled ocean-atmosph ere research problems, is also brought out.