Upwelling and sinking along Visakhapatnam coast

Abstract

Stability and stratification of the water over the shelf disappear as cold saline waters characteristic of 60 m depth rise to the surface during March. Tilting of isopycnals and offshore displacement of isohalines suggest the surface divergence typical of a coastal upwelling driven by local wind stress. Upwelling is predominant off Visakhapatnam during premonsoon and monsoon periods. Waters from the deeper depths of the shelf appear to reach the surface causing considerable fall of temperature near the coast particularly during the premonsoon period