Heat Balance of the East China Sea during the Air Mass Transformation Experiment

Abstract

Transfers of heat and momentum in winter for the East China Sea and adjacent seas were estimated by means of an aerodynamic bulk method under diabatic conditions. It is found that at the Kuroshio region the sensible and latent heat losses (H+lE) are primarily compensated for by the heat convergence caused by the oceanic eddy and/or current transport. The secondary contribution to the heat balance is due to the net flux radiation and the oceanic heat storage. On the basis of heat balance consideration, the thermal diffusivity of the ocean of K= 1.0×108cm2 s-1 is obtained for a period of about one month. There is also suggested that in the Yellow Sea there occurs a counterclockwise circulation of water.
The average value of H+lE over the AMTEX area for the entire period of AMTEX '74 is by about 10 to 20% smaller than the climatological normal value for he corresponding period. The value of H+lE estimated by the present aerodynamic method agrees in general with those obtained by the atmosph ric budget computations by Nitta (1976) and Murty (1976) for both the period of AMTEX '74 and AMTEX '75. During an intense cold-air outbreak the very large amount of latent heat of about 500 to 800W m-2 is supplied to the atmosphere over the Kuroshio, while only a small amount is supplied to the atmosphere over the shallow seas of the continental shelf. The Bowen ratio (H/lE) is about 0.7 to 0.8 over the Yellow Sea, whereas it is 0.3 to 0.4 over the AMTEX region, and 0.1 to 0.2 over the sub-tropical ocean.