The Ocean Heat Content Changes in the South China Sea due to Tropical Cyclones with Different Tracks

Abstract

The influences of the tropical cyclones (TCs) on the ocean heat content (OHC) of the South China Sea (SCS) was investigated by observations and numerical simulations. Ensemble analyses based on observations showed notable differences in OHC changes caused by TCs with different tracks: (1) TCs which generated over the western North Pacific (WNP) and did not enter the SCS (TC-P) decreased the OHC mainly in the central SCS while increasing the OHC in southern SCS and coastal areas along South China; (2) TCs which generated over the WNP and entered the SCS (TC-PS) decreased the OHC in most of the SCS beyond the coastal areas with a higher amplitude than that caused by TC-P; and (3) TCs which generated over the SCS (TC-S) induced the strongest OHC decrease and a distinct OHC increase in the southeastern SCS and Sulu Sea (SS). The distinct response of the SCS OHC was mainly attributed to the different surface heat fluxes and oceanic transports caused by TCs. Strong surface heat flux proximal to TC tracks led to ocean heat release to the atmosphere and decreased the OHC in these areas, while the oceanic current caused by the TC cyclonic wind field transported the OHC to areas distant from the TC center. Eastward transport of the OHC south of 15° N increased the OHC in the southeastern SCS and SS. These results expressed the detailed response of the OHC to TCs with different tracks over the WNP and SCS, and clarified the influences of TCs on the ocean environments of the SCS and for predicting the changes in the SCS.