南海海表盐度变化特征及机制研究OACSTPCD

The variation mechanism of Sea Surface Salinity(SSS)is complex and mainly affected by air-sea exchange and ocean circulation processes.There are significant inter-annual and inter-decadal variations of SSS in the South China Sea,and the compound effects of ENSO and PDO is still unclear.In this paper,the long-term SSS dataset of the South China Sea for 151 years(1871-2021)was genera-ted by integrating Marine reanalysis data and satellite remote sensing data.The long-term spatio-tempo-ral characteristics and mechanisms of SSS in the South China Sea were analyzed by using EOF and corre-lation analysis methods.The results show that the overall SSS of the South China Sea has not changed significantly in the past 150 years,but the SSS increased significantly(0.31per/decade)from 1940 to 1958.The variation of SSS in the Pearl River Estuary and Luzon Strait under the influence of runoff and Kuroshio was the largest(-0.04 and 0.03 per/decade).The overall variation of SSS in the South China Sea was mainly controlled by precipitation and Kuroshio,with correlation coefficients of-0.41 and-0.49,respectively.SSS in the continental shelf and offshore areas of the South China Sea were signifi-cantly affected by river runoff,with correlation coefficients of-0.51.ENSO controls the precipitation in the South China Sea in the inter-annual scale,while PDO affects the change of the invasion of the Kuroshio in the South China Sea in the inter-decadal scale.When the PDO is in the positive phase,the occurrence of El Nino will lead to the decrease of precipitation,and the intensity of the invasion of the Kuroshio in the South China Sea will increase,so the SSS of the South China Sea increases significantly.This study is of great significance for understanding air-sea exchange and ocean circulation in the South China Sea.