UPWELLING DYNAMICS AND WATER ADVECTION ALONG THE PENINSULAR MALAYSIA’S EAST COAST AND ITS RELATION TO CLIMATE VARIABILITY IN THE TROPICAL PACIFIC

Abstract

The southern South China Sea (SCS) and Java Sea are connecting water bodies but the knowledge of the interaction between these water bodies are vague, particularly in the boreal summer when the waters from the Java Sea merged with the upwelling water along the Peninsular Malaysia’s east coast (PMEC). The upwelling along the PMEC is a newly discovered feature after the 21st century. Therefore, its understanding particularly the upwelling-driven processes and its interannual variability are equivocal. Considering that the SCS and Java Sea play an important role in regulating the regional climate system and the upwelling is important in primary productivity, thus it is important to understand the interconnection between the southern SCS and Java Sea as well as the upwelling along the PMEC. This study employed the Regional Ocean Modelling System (ROMS) to simulate the circulations between the southern SCS and Java Sea as well as the upwelling along the PMEC. In addition, cruise surveys and satellite data were used to provide datasets of upwelling features. The patterns of circulation and seasonal water transport between the southern SCS and Java Sea were governed by the seasonal reversal of circulation. In the boreal winter, the cooler and saltier waters of the southern SCS were advected to the Java Sea. In the boreal summer, the cooler and fresher waters from the Java Sea were advected to the southern SCS and merged with the upwelling water along the PMEC. The upwelling along the PMEC had a greater effect on the sea surface temperature (SST) where it further cooled down the already cooled water from the Java Sea.