Influence of Synoptic Processes on the Vietnamese Current (the South China Sea) Dynamics during the Winter–Summer 1999 Transition Period

G. A. Vlasova, Nguyen Ba Xuan, and Bui Hong Long

Demonstrated is an influence of synoptic processes on the seasonal dynamics of the Vietnamese Current in the South China Sea varying its direction under the influence of the monsoon. The spring season of 1999 is used as an example of the transition from the winter to summer. In winter, under the influence of the northeastern monsoon, the current is directed from north to south and in the summer, at the southwestern monsoon, in the opposite direction. In the spring, two zones of different water modification are formed: an impact is observed of both the leaving winter monsoon and the coming summer monsoon. Considered is an atmospheric process of low-gradient field type, when the pressure field is characterized by the low pressure gradient over the whole South China Sea. It is revealed that the Vietnamese Current moves in the summer regime (from south to north) in the northern and southern parts and keeps the winter regime (from north to south) in the central part.