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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. Plain Language Summary: 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. Key Points: 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 [ABSTRACT FROM AUTHOR]

This study investigates the deep circulation in the South China Sea (SCS) using oceanographic observations combined with results from a bottom layer reduced gravity model. The SCS water, 2000 m below the surface, is quite different from that in the adjacent Pacific Ocean, and it is characterized by its low dissolved oxygen (DO), high temperature and low salinity. The horizontal distribution of deep water properties indicates a basin-scale cyclonic circulation driven by the Luzon overflow. The results of the bottom layer reduced gravity model are consistent with the existence of the cyclonic circulation in the deep SCS. The circulation is stronger at the northern/western boundary. After overflowing the sill of the Luzon Strait, the deep water moves broadly southwestward, constrained by the 3500 m isobath. The broadening of the southward flow is induced by the downwelling velocity in the interior of the deep basin. The main deep circulation bifurcates into two branches after the Zhongsha Islands. The southward branch continues flowing along the 3500 m isobath, and the eastward branch forms the sub-basin scale cyclonic circulation around the seamounts in the central deep SCS. The returning flow along the east boundary is fairly weak. The numerical experiments of the bottom layer reduced gravity model reveal the important roles of topography, bottom friction, and the upwelling/downwelling pattern in controlling the spatial structure, particularly the strong, deep western boundary current. [ABSTRACT FROM AUTHOR]