11th Conference on Satellite Meteorology and Oceanography

Monday, 15 October 2001
TOPEX/POSEIDON ALTIMETRY REVEALS THE VIETNAM SUMMER RECIRCULATION
Eric J. Bayler, Univ. of Wisconsin, Madison, WI; and Z. Liu
Poster PDF (148.2 kB)
The sea surface height anomalies (SSHA) for the South China Sea, provided by TOPEX/Poseidon altimetry, indicate the presence of seasonal recirculation along the coast of Vietnam. With each regime shift, the monsoon forcing of the ocean circulation in the South China Sea reverses the western boundary current along Vietnam. During the summer southwest monsoon, an anticyclonic recirculation cell develops near 12 North 111 East, consistent with large-scale recirculation theory. The subsequent transition to the winter northeast monsoon regime destroys this recirculation cell. This investigation employs high-resolution 1.5 and 2.0-layer numerical models to demonstrate the applicability of large-scale recirculation dynamics to the deep basin of the South China Sea, specifically to show that the gyre-scale circulation determines the development of the Vietnam Summer Recirculation. In addition to demonstrating the development of inertial recirculation by mean seasonal wind forcing, the seasonal destruction of the recirculation by the migrating monsoon winds is also modeled and shown to be consistent with TOPEX/Poseidon observations. The sequential wind forcing for the model uses values derived from the European Remote Sensing (ERS) satellite scatterometer observations covering the same time period as the TOPEX / Poseidon altimetry observations. The migrating monsoon wind forcing highlights the driving role of gyre-scale dynamics in the formation and destruction of the Vietnam Summer Recirculation.

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