Observed signals of upwelling and downwelling along the west coast of India

Abstract

Present study indicates the extension of upwelling to the northern part of the west coast of India. Upwelling along the southwest coast of India starts at the southern tip during April, propagates northward as the summer monsoon progresses and ends by September. However along the northwest coast, the upwelling intensifies during August and continues till October. The southwest coast is characterized by downwelling during October to March, whereas along the northwest coast upwelling comes to an end by November and sinking occurs during December to March. Compared to the northwest coast, both upwelling and downwelling are stronger along the southwest coast of India. During the peak southwest and northeast monsoon, magnitude of the mean vertical velocity with respect to 100m depth is 2.15 x 10-5m/s and 0.76 x 10-5m/s along the southwest and northwest coast, respectively.