The warm sea current Kuroshio is very strong in the East China Sea. During the winter season the polar-continental air-mass breaks out over the warm sea so that a large amount of sensible heat and water-vapor are supplied from the ocean and produce a remarkable air-mass modification.
The heat and water-vapor budget over the East China Sea is analysed with special emphasis on the relations among the energy supply, the convective transfer of heat energy and the synoptic weather situations in February of 1968 by using aerological data.
The heat and moisture supply from the sea surface are also evaluated by using the bulk method basing on marine observation data for the February of 1966, 1967, and 1968.
The amount of the sensible heat supply and the evaporation are estimated to be 300 ly•day
-1 and 10 mm day
-1 respectively both by budget calculations and by bulk method.
During the period of the analyses in February 1968, predominant synoptic-scale disturbances developed with a period of about 4-day over the East China Sea region. The amount of the energy supply from the sea increases remarkably under the situation of the polar-air outbreak.
The terms concerning the convective transfer of heat and moisture are introduced in the largescale budget equation and the magnitudes of the transfer across various levels are estimated.
It is shown that the magnitude of the convergence of the horizontal water-vapor flux in the lower layer and that of the convective transfer of heat energy increases remarkably when the cyclone developes in the East China Sea region. It is suggested that the convergence of the water-vapor flux in the lower troposphere would play an important role, as well as the energy supply from the ocean, for the development of the cyclone in the East China Sea region in winter season.
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