Unveiling of the SST gradient over the South China Sea and its possible relationship to the Asian precipitation

Abstract

The present study examines the Sea Surface Temperature (SST) variations over the South China Sea (SCS) using the National Oceanic and Atmospheric Administration (NOAA) SST daily datasets for the period 1988–2009. In the SST over the South China Sea (SCS), a north-west versus south-east SST gradient (hereafter gra-SCS SST) is revealed. This SST gradient is seen to be induced by the distinct wind anomaly along with fresh water flux changes. The slope difference between the gra-SCS SST before and after 1999 is observed to be statistically significantly different than zero at a 95% confidence level. A decreasing/increasing trend in the gra-SCS SST is revealed before/after 1999. Besides, it is found that the gra-SCS SST characterizes the Asian monsoon variability by inducing cross equatorial monsoon flow towards the Asian Continent. In addition, we established the role of the gra-SCS SST in the Asian monsoon by computing causation based on the information flow concept between the gra-SCS SST and traditional monsoon indices, which pronounces that former impact the later. Based on the present corollary, we suggest that the gra-SCS SST should be considered as an important parameter in the climate studies as it is meticulously related to the precipitation over Asia.