Upwelling and associated hydrography along the west coast of india during southwest monsoon, 1999

Abstract

During May 1999 twenty-five hydrographic stations were carried out covering the waters of the west coast of India from 8 degrees N to 13 degrees N as a part of Marine Research - Living Resources (MR-LR) programme. The inference on upwelling and related hydrography is discussed. Analysis of wind field and hydrography indicated active upwelling along the southwest coast of India. The sea surface temperature near the coast were lower by 1.7 degrees C (off Kanyakumari), 1.4 degrees C (off Cochin) and 1.2 degrees C (off Mangalore) from the farthest stations, indicating the presence of upwelled water near the coast. Well defined thermal, saline and density fronts were visible. Relatively high offshore transport was observed off Kanyakumari. Signatures of coastal under current were prominent which deepens, as moving towards north. Analysis of hydrographic characteristics reveals the presence of cool upwelled water by May itself. Strong signals of upwelling were observed off Kanyakumari, relatively less off Cochin and weak off Mangalore indicating the propagation of this seasonal phenomenon towards north with time.