VARIABILITY OF THE FLOW-FIELD IN THE INNER SHELF ALONG THE CENTRAL EAST-COAST OF INDIA DURING APRIL-1989

Current measurements collected along the inner shelf off the central e ast coast of India (water depth similar or equal to 50 m) at three sta tions, A (17 degrees 59'N, 83 degrees 53.9'E), B (17 degrees 00'N, 82 degrees 32.1'E) and C (16 degrees 31.3'N, 82 degrees 21.8'E) during th e cruise 211 of R.V. Gaveshani (April 1989) are discussed. Data analys is show there to be two layer circulation at Sta. A: a northerly flowi ng current, which is restricted to the surface and southerly flowing c urrent at mid water depth and near the bottom. Southerly flowing curre nt occupies the whole of the water column at Sta. B and northerly flow ing current at Sta. C. The striking divergence of the mean velocity fi eld between Stas B and C is due to disparate advection states of the l ocal eddy field. The mean southerly velocity of 6-12 cm s(-1) from the surface to 45 m depth at Sta. B, and northerly velocity of 84-121 cm s(-1) from the surface to 45 m at Sta. C suggesting that the meridiona l flow is substantially baroclinic. The onshore-offshore component of the currents is much smaller than the alongshore current at all the st ations. The upwelling circulation off Kakinada was generally three lay ered: the surface offshore flow was confined to approximately the uppe r 10 m, the compensating onshore flow was maximum at mid depth (about 30 m) and there was weak offshore flow along the bottom. The large val ues of both K-e and K-m encountered at Sta. C are consistent with the idea that, in this region, baroclinic instability is converting potent ial energy of the strong mean flow into fluctuation energy. The overal l K-e decreases northward from Sta. C to Sta. A represent the interior of the northern anticlockwise gyre.