Title: Interannual modulation of eddy kinetic energy in the northeastern South China Sea as revealed by an eddy-resolving OGCM

Journal: Journal of Geophysical Research: Oceans, 121(5): 3190-3201

Authors: SUN Z. -B., Z. -W. Zhang, W. Zhao*, and J.-W. Tian

Abstract:Interannual modulation of eddy kinetic energy (EKE) in the northeastern South China Sea (NE-SCS) is investigated based on outputs of an eddy-resolving oceanic general circulation model between 1980 and 2014. The EKE displays distinct interannual modulations with periods between 1.5 and 7 years. The maximum peak-to-trough amplitude of the interannual modulation occurred during period 2004–2005, which was about 1.5-fold the time-mean EKE level. Further analysis suggested that interannual variability of EKE in the NE-SCS is primarily modulated by the Luzon Strait transport (LST). During high-EKE years, the LST increases corresponding to a strengthened Kuroshio intrusion. The strengthened Kuroshio intrusion enhances the baroclinic instability of current in the NE-SCS and thus leads to a strong EKE. The reverse is true during low-EKE years when LST is smaller. Influences of ENSO and Pacific mesoscale eddies on the interannual modulation of LST are also discussed in this study.