Different roles of Ekman pumping in the west and east segments of the South China Sea Warm Current

A three-dimensional model is used to investigate the mechanism of the South China Sea (SCS) winter counter-current (also known as the SCS Warm Current, or the SCSWC), which flows against the wind. The model can reproduce the structure of the band-like currents over the northern shelf of the SCS, including the westward coastal current and slop current, and the SCSWC sandwiched in between. Sensitivity experiments are designed to understand the different roles of Ekman pumping of the SCSWC at different longitude. The results show that the Ekman pumping drives the SCSWC in the west segment. In the east, it is not the Ekman pumping but the intrusion of the Kuroshio that drives the SCSWC.