Interannual variability of winter eddy patterns in the eastern South China Sea

Merged altimetry data collected over 21 years are analyzed to study the interannual variability of winter eddy activities in the eastern South China Sea (SCS) associated with the El Nino-Southern Oscillation. Composite analyses of eddy probability reveal that a Luzon cold eddy (LCE) northwest of the Luzon Island, an anticyclonic eddy northwest of the Mindoro Island (referred as MAE) and a cyclonic eddy west of the Mindoro Island (referred as MCE) are common for winter. Further studies indicate that LCE and MAE weaken and MCE strengthens in El Nino winters, whereas data show the opposite behavior for La NiNa winters. In addition, the geographical pattern of MAE and MCE in an El NiNo winter is different from that in a La NiNa winter. The interannual wind curl anomalies west of the Luzon and Mindoro Islands and the outflow from the SCS via the Mindoro Strait may be responsible for the interannual eddy variability.