Seasonal Variations of Upper Ocean Circulation over the South China Sea from Satellite Altimeter Data of Many Years

Abstract

In combination with the topography model EGM96 for stationary sea surface, we use high-precision grid data of sea surface anomaly from satellite altimeter measurements in ten years to construct the time series for the formation of the sea surface topography in the South China Sea and calculate the circulation fields of its upper layer in different periods. Comparison between the satellite tracing observations to drifting buoys and the geostrophic current fields in corresponding times indicates that the circulation fields derived by this study can reveal some characteristics of the circulation and eddy over the South China Sea on medium- and small-scales. Based on the circulation field structure of the uppermost layer of the South China Sea averaged to seasons of many years, we make a preliminary analysis of the annual and seasonal variations of the circulation in the study area. The result shows that the circulation of the uppermost layer of the South China Sea is always in a constant process of change and evolution which exhibits pronounced multi-scale characteristics both in time and space.