Geotrophic and drift current in the South China Sea, Area IV: Vietnamese waters

Abstract

The water circulation in area IV was calculated by 2 methods. The circulation for the area where water depth exceeded 600m was calculated by the geostrophic balance method. In a shallow water area effect of wind absolutely surpasses geostrophic balance, so wind induced drift current is greater than geostrophic current many times. So, for the whole area (shallow deep) the drift current was calculated by two-dimensional nonlinear shallow water equation based on typical monsoon fields. The results of 2 methods showed common picture of the circulation with divergence and convergence changing by season.