Multi-temporal patterns of upwelling-downwelling dynamics in the South China Sea based on a 47-year time-series of the NOAA-ERD upwelling index

Over the past decades, upwelling research has intensified in the South China Sea resulting in interesting findings about the phenomenon and its drivers especially at seasonal, intra-seasonal and annual timescales. However, whether upwelling variability follows well defined and coherent cycles on a multi-temporal basis, remains a least examined area of research. This is understandable because previous studies have been largely based on various proxy variables which limits the predictability of upwelling intensity. Consequently, a recently developed time-series of upwelling index (1967-2014),generated across northern South China Sea (NSCS): off Fujian, Guangdong, Hanoi and S.W. Taiwan, using NOAA-ERD model has been analyzed using a number of complementary statistical methods. The results reveal four distinct temporal modes of upwelling/downwelling variability including: seasonal, annual, inter-annual and Decadal patterns. A summary of the outcomes of this study is as follows: