Variability of sea surface salinity and chlorophyll in the Yellow and East China Sea: ENSO effects

Abstract

El Ni&ntilde o&#8211 Southern Oscillation (ENSO) has known to affect inter-annual variability in both physical and biological aspects in relation in the Yellow and East China Seas (YECS). In this study, we examine inter-annual variability of summer sea surface salinity (SSS) and chrolophyll (CHL) in the YECS and its relation with ENSO, using a global ocean general circulation model (OGCM) with a regional focus on the YECS. A cyclostationary EOF (CSEOF) shows that Changjiang River discharge (CRD) contributes to the dominant inter-annual variability of the SSS in the YECS. The variability of the CRD is linked to ENSO through changes in precipitation over the Changjiang River. When El Ni&ntilde o events occur in winter, precipitation over the Changjiang River increases in the rainy season of the following year through enhanced southwesterly moisture flux from the South China Sea into southern China. The increased CRD in El Ni&ntilde o years also appears to increase CHL-a concentration by supplying more nutrients into the YECS, suggesting that the ENSO is likely to affect biological production in the YECS by changing CRD. Our finding suggests that ENSO may contribute to inter-annual variability of both physical and biological processes in the YECS by modulating CRD through precipitation changes over the Changjiang River. of summer sea surface salinity (SSS) and chrolophyll (CHL) in the YECS and its relation with ENSO, using a global ocean general circulation model (OGCM) with a regional focus on the YECS. A cyclostationary EOF (CSEOF) shows that Changjiang River discharge (CRD) contributes to the dominant inter-annual variability of the SSS in the YECS. The variability of the CRD is linked to ENSO through changes in precipitation over the Changjiang River. When El Ni&ntilde o events occur in winter, precipitation over the Changjiang River increases in the rainy season of the following year through enhanced southwesterly moisture flux from the South China Sea into southern China. The increased CRD in El Ni&ntilde o years also appears to increase CHL-a concentration by supplying more nutrients into the YECS, suggesting that the ENSO is likely to affect biological production in the YECS by changing CRD. Our finding suggests that ENSO may contribute to inter-annual variability of both physical and biological processes in the YECS by modulating CRD through precipitation changes over the Changjiang River.