Spatiotemporal characteristics of mesoscale eddies in the South China Sea and the influence mechanism of Eddy Kinetic Energy

Abstract

This paper uses 28 years of satellite altimeter fusion data from 1993 to 2020 to identify and track the mesoscale eddies in the South China Sea based on the Sea Level Anomaly (SLA) closed contour method, with the goal of improving our overall understanding of mesoscale eddy activities in the South China Sea and further investigating the ocean dynamic processes in the region, so as to provide fundamental data for climate change studies. The study examined the spatiotemporal distribution, generation and demise, and movement trajectories of the eddies. Furthermore, key parameters including velocity, vortex radius, amplitude and Eddy Kinetic Energy (EKE) were analyzed, with a particular emphasis on the seasonal changes and mechanisms that influence EKE in two areas of the South China Sea with high energy values. The South China Sea has more cyclonic eddies than anticyclonic eddies, according to the study, and its eastern region is primarily home to high-frequency generating areas. However, the majority of the vortices will eventually dissipate in the western and central areas of the South China Sea. Furthermore, vortices usually flow farther to the west. With decreasing latitude, the eddy radius and EKE distribution gradually increase, whereas the amplitude is contrary. EKE is caused by the interaction of factors including wind field driving, seawater movement, and circulation. Seasonal changes in the EKE occur near the Luzon Strait, and the sea area east of the south in Vietnam exhibits clear characteristics.