Annual and seasonal mean buoyancy fluxes for the tropical Indian Ocean

• Published in: Current science (Bangalore) 1997-10, Vol.73 (8), p.667-674
• Main Author: Prasad, T. G.
• Format: Article
• Language: English
• Subjects: Buoyancy; Equatorial regions; Evaporation; Fresh water; Heat flux; Marine; Oceans; Precipitation; Seas; Tropical regions; Winter
• ISSN: 0011-3891

INSAT-derived monthly mean precipitation, combined with estimates of evaporation from COADS, are used to prepare the annual mean and seasonal distributions of evaporation–precipitation (E–P) and buoyancy fluxes for the tropical Indian Ocean. The fluxes of heat and freshwater across the air–sea interface, and hence the surface buoyancy flux, show strong spatial and temporal variability. The Bay of Bengal and eastern equatorial Indian Ocean are characterized by a net freshwater gain due to heavy precipitation, while the northern Arabian Sea and the ocean south of 10°S experience a net loss of freshwater due to excessive evaporation. The regions of high and low salt flux broadly correspond to those of high and low E–P and the seasonal fluctuations of E–P appear to contribute to the seasonal cycle of salt flux. The buoyancy flux is dominated by strong density loss by the ocean in the northern Indian Ocean and modest density gain in the southern Indian Ocean. Though heat flux is the dominant contributor to the buoyancy flux over most of the region, salt flux dominates during winter in the northern Arabian Sea and during summer and fall in the Bay of Bengal and the eastern equatorial Indian Ocean.