Hydrography and circulation in the western Bay of Bengal during the northeast monsoon

摘要: The Bay of Bengal, a semienclosed tropical basin that comes under the influence monsoonal wind and freshwater influx, is distinguished by strongly stratified surface layer seasonally reversing circulation. We discuss characteristics these features in western during northeast monsoon, when East India Coastal Current (EICC) flows southward, using hydrographic data collected December 1991. Vertical profiles show uniform temperature salinity homogeneous layer, on average, 25 m deep but shallower northward coastward. halocline, immediately below, approximately 50 thick; changes 3 parts per thousand. About two thirds inversions this layer. Salinity below halocline hardly changes, stratification predominantly due to variation, noticeably better developed thinner low-salinity plume hugs coastline along entire east coast India, is, km wide, with isohalines sloping down toward coast. Most prominent geostrophic velocity field equatorward EICC. Its transport north about 13 degrees N, computed 1000 dbar as level reference, varies between 2.6 7.1 x 10(6) m(3) s(-1); just south latitude, northwestward flow from offshore recurves merges coastal current. At southern end region surveyed, 7.7 s(-1). Recent model studies lead us conclude EICC monsoon driven winds Ekman pumping interior bay. In south, over southwestern bay responsible for