On the flow, thermal field and winds along the Western continental shelf of India

Abstract

Short duration current meter recordings during May 1984, March 1986 and November 1986 along with wind and hydrographic data at a point (15°08'N and 73°16'E) in the western continental shelf of India were analysed for mean flow characteristics and for their possible relationship with wind and mass field. The analyses show that the mean alongshore flows (V) during May and March are towards south and during November, towards north. The barotropic and baroclinic components of the observed flow and the correspondence between the alongshore components of the flow and the wind stress suggest that the alongshore flows are mainly barotropic and wind driven. The correlation coefficients computed between pairs of U and V components also support this proposition. The mass field is found to be in agreement with the observed alongshore flow during May, but it does not favour the observed northward flow during November. This discrepancy during November is explained as due to the time lag in the adjustment of the mass field to the wind driven flow during the transition phase. It is further suggested that along the west coast of India, the impulse needed to trigger the flow reversal during October-November is provided by the wind. The process of flow reversal starts near the coast first and propagates slowly offshore.