Impacts of the Kuroshio intrusion on the two eddies in the northern South China Sea in late spring 2016

During mid-May to early June 2016, a cold eddy and a warm eddy were captured on the continental slope of the northern South China Sea by the in situ measurements. A salty lens-shaped water mass in the subsurface layer existed in these two detected eddies, which indicated they had a Kuroshio water origin. The trajectories of the observed eddies from satellite altimeter data show that the cold eddy was generated in the central part of the Luzon Strait, while the warm eddy was formed southwest of Taiwan. The genesis of the cold eddy is related to a weak Kuroshio loop current, while that of the warm eddy is associated with a strong Kuroshio loop current. The warm eddy east of the Luzon Strait may trigger the Kuroshio from a leaping path to a looping path. During the evolution of these detected eddies, they had interactions with the Kuroshio and Luzon Gyre. Energy analysis from ocean reanalysis data showed that the baroclinic conversion between the cold eddy and the Kuroshio was stronger than that between the cold eddy and Luzon Gyre. During the eddy shedding stage, the warm eddy mainly acquired energy from the Kuroshio loop current through the baroclinic conversion.