Abstract
The mechanisms driving the annual cycle of the South China Sea surface temperature are examined using the 1979-1999 NCEP/NCAR reanalysis data. The cycle is not symmetric. The summer half-year from May to October is the warm phase with the sea surface temperature decreasing slowly. This slow decrease is due to the effect of oceanic processes that overcome the net surface heating. The winter halfyear is the cold phase with a rapid decrease in sea surface temperature from October to January followed by a rapid rise from February to May. These rapid temperature changes are dominated by net surface heating with negligible effects from oceanic processes. The net surface heating is mainly a result of the offsetting between heating due to shortwave radiation and cooling due to latent heat flux and longwave radiation, whose magnitudes have an approximate ratio of 3:2:1. The rapid warming and cooling periods can both be accounted for by the opposite variations of shortwave radiation heating and wind speedregulated evaporation cooling.
