Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019

Abstract

Using Estimating the Circulation and Climate of the Ocean (phase 2, ECCO2) reanalysis products from 1997 to 2019, this study analyzes the spatiotemporal features of the eddy available gravitational potential energy (EAPE) in the South China Sea (SCS). The results indicate that the EAPE accounts for 64% of the total APE in the SCS with the climatological mean. The 2D EAPE distribution images manifest show high-value regions which are generally consistent with the eddy distributions. One region is located around 21° N and west of the Luzon Strait, the second around 17° N and near Luzon Island, and the third off the Vietnam coast. In the region around 21° N and 17° N, both the seasonal variability and the interannual variability associated with the El Niño–Southern Oscillation (ENSO) are significant. Off the Vietnam coast, the EAPE is closely associated with coastal processes which heavily depend on the seasonal monsoon, the El Nino/La Nina events, and the Indian Ocean Dipole (IOD). The results provide new insights into SCS dynamics from the point of view of ocean energy sources.

Keywords

• available gravitational potential energy
• mesoscale eddy
• South China Sea
• ENSO
• IOD