Influence of Two Eddy Pairs on High‐Salinity Water Intrusion in the Northern South China Sea During Fall‐Winter 2015/2016

Two processes of high‐salinity water (≥34.7 psu; HSW) intrusion were recorded by an Argo float in the northeastern South China Sea (SCS) during fall‐winter of 2015/2016. Combined with the satellite altimetry and reanalysis data, the influence of related eddy pairs on HSW transport was investigated. The results show that apart from the Kuroshio‐originated anticyclonic eddy (AE), the localized cyclonic eddy (CE), and the westward jet between the eddy pair all contributed to the HSW transport. In the first process, the effect of eddy trapping accounted for 74% of the HSW transport, while the associated jet accounted for the residual 26%. The contribution of the southern CE was stronger than that of the northern AE. In the second process, the Kuroshio‐originated AE and its southern jet dominated the HSW transport. The westward jet conveyed abundant HSW to the interior SCS before the eddy pair propagated westward, accounting for 52% of HSW transport, while AE accounted for 43% and CE for 5%. Energy analysis showed that barotropic and baroclinic instabilities were important for the generation and growth of the AE in both processes, and CE in the first process was produced by baroclinic instability and wind stress work, while CE in the second process was predominantly triggered by barotropic instability. The development of eddy pairs combined with the SCS interior circulation jointly affected the HSW transport. This study identified the important contributions from two eddy pairs and discussed the effect of interior circulation‐Kuroshio interaction on HSW intrusion in the northern SCS. In this study, we report a special case in which two successive anticyclonic eddies were shed from the Kuroshio into the South China Sea (SCS) during fall‐winter of 2015/2016. We focus on the high‐salinity water (HSW) intrusion induced by the eddy pair that includes the Kuroshio‐originated anticyclonic eddy and the localized cyclonic eddy. The eddies and their associated jet contribute to the transport of HSW from the western Pacific to the northern SCS. The relative contributions of eddy trapping and jet transport were related to the development of the eddy pair and the interior circulation in the SCS. Two processes of eddy pair intrusion were revealed in the northeastern South China Sea during fall‐winter of 2015/2016The northern anticyclonic and southern cyclonic eddies, together with their associated jet, affected the high‐salinity water transportThe interior circulation and the development of eddy pairs jointly affected the relative contributions of eddy trapping and jet transport Two processes of eddy pair intrusion were revealed in the northeastern South China Sea during fall‐winter of 2015/2016 The northern anticyclonic and southern cyclonic eddies, together with their associated jet, affected the high‐salinity water transport The interior circulation and the development of eddy pairs jointly affected the relative contributions of eddy trapping and jet transport