Journal of Marine Science: Research & Development
Open Access

Abstract

Indian summer monsoon is characterized by the formation of intermittent monsoon organized convections. These are formed in the equatorial region and move to the north up to the foot hill of Himalayas within 2 to 4 weeks. It is found that mud banks (calm water with a high load of suspended sediments and high chlorophyll-a concentration) are formed on the coast of southwest peninsular India. Mud bank is a peculiar eco system with high bio-productivity and is a favourable occasion for the high fish catch. The objective is to understand the role played by monsoon system for intermittent high bio-productivity in the coastal waters of southwest the Peninsular India. The analysis is carried out utilizing daily OLR, QuikSCAT wind, NCEP wind and chlorophyll-a concentration. It is found that the low level wind is directed towards the region of monsoon organized convection. When the organized convection is in the equatorial region, the low level wind over the southwest peninsular India blows parallel to the coast. This alongshore wind gives rise to Ekman mass transport away from the coast and subsequent upwelling in the coastal region, resulting nutrient rich subsurface water to occupy the surface. Strong alongshore winds persisting for 3 days makes high bio-productivity in the coastal waters as evidenced by chlorophyll-a concentration. The strength of alongshore wind decreases as the organized convection moves to the north since wind direction turns to westerly. Further details about features of monsoon organized convection, alongshore wind and factors favourable for the formation of high bio-productivity are included in the presentation.

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