Circulation in the north Arabian Sea at Murray Ridge during S.W. monsoon

Abstract

Circulation in the Arabian Sea north of 20°N has been observed to contain warm and cold core eddies. These have been confirmed from various investigations during the International Indian Ocean Expedition (1962–1967) and subsequent oceanographic surveys. Satellite imageries using records of high resolution infrared radiometer have also delineated these eddies with more clarity. The eddy circulation appears to get intensified and in some areas persists in the SW monsoon (May–September). These months are dominated by upwelling along the Arabian coast and the cold water plumes and wedges extend eastward. Upwelling, comparatively weak, also appears along the Pakistan coast, west of Karachi. In the middle of these two upwelled cold water areas an anticyclonic eddy is found with warm core. Records generally show that this eddy circulation is repeated in the S.W. monsoon. Interaction of permanent seabed topographic features like the Murray Ridge and continental shelf on the eddy field, if any, has been studied. This eddy circulation favoured the vertical and horizontal mixing of nutrient rich water.