The modeling responses of heat budget in the Eastern China Seas to global warming

Impacts of climate change on heat budget in the Eastern China Seas (ECSs) are estimated under the historical, RCP4.5 and RCP8.5 scenarios using an atmosphere-ocean coupled regional climate model system (REMO/MPIOM). Solar radiation contributes the largest heat source of the ECSs. The heat gain achieved by solar radiation is overruled by thermal radiation, latent heat flux and sensible heat flux released at the ocean surface. The air-sea heat exchange thus cools the ECSs, whereas an overall warming is found for the ECSs. An increased oceanic heat transport by ocean currents balances this reduced heat supply by the sea surface heat fluxes. In particular, the water transport through Taiwan Strait brings the largest amount of heat into the ECSs. Despite of an inward heat transport onto the ECS shelf caused by the Kuroshio intrusion occurring northeast of Taiwan, overall, the shelf break section acts as a heat sink for the ECSs. The net heat gain/loss by the Tsushima Strait is marginal. Under the climate projection scenarios, the net heat loss from the shelf break section reduces, probably associated with the change in surface wind. Thus the net heat transported into the ECSs through the lateral boundaries increases slightly under these scenarios, leading to an overall warming of the ECSs, relative to 20C run. Noteworthy, the warmer SST, along with strengthened wind, further enhances the surface evaporation, providing a negative feedback onto the net effect of oceanic transport.