Variability of Mixed Layer Depth in the Northern Indian Ocean during 1977 and 1979 Summer Monsoon Seasons

Abstract

Influences of wind stress (tau) and wind stress curl (Grad Gamma) on the short term variability of the mixed layer depth at different locations in the northern Indian Ocean during different phases of summer monsoon activity were examined quantitatively making use of time-series data collected during MONSOON-77 and MONEX-79 programmes. After the onset of monsoon (June/July 1977) over the central Arabian Sea, wind stress together with possible sinking processes on account of negative wind stress curl and convective turnover seemed to play an important role in the development of mixed layer while in the southern Arabian Sea region, the mixed layer mainly responded to the wind stress forcing, whose magnitude though was one order less during May/June 1979. In the northern Bay of Bengal the correlation between wind stress and mixed layer was weak indicating influence of stratification caused by the fresh water discharges from Hooghly and Brahmaputra rivers.