The Comparison between the Geostrophic Current Field and the Water Mass Distribution in the South China Sea

Using geopotential anomaly fields and distribution patterns of the North Pacific Tropical Water and the North Pacific Intermediate Water, the circulation in the upper and intermediate layers of the South China Sea is described. In summer, three eddies are found in the upper layer, while a small anti-cyclonic circulation exists in the intermediate layer in the central part of the South China Sea. In winter, a cyclonic circulation occupies the entire South China Sea basin in the upper Iayer, while the existence of a double-gyre pattern is suggested in the intermediate layer.