| China lies to northwest Pacific Ocean, including Tropical Zone, Subtropical Zone and Mid-latitude Zone. Continent coastal climate is variable. China Sea is divided into Chinese Shelf Sea and South China Sea by the Taiwan Strait. The dynamic characters of Yellow East Sea and South China Sea are very interesting to the ocean scholars all over the word. The two parts is interacting closely, and influenced with each other. At the same time, China Sea is bordered on the northwest Pacific Ocean; especially the SCS is the biggest pericontinental sea, which is one of the three tropical cyclone cradle lands in the northwest Pacific Ocean. Then the climate and the air-sea interaction become more complex. Studies of circulation systems in China Sea area and the air-sea interaction in the mesoscale weather process can provide theoretical basis and more reliable methods to forecast the climate and the ocean environments contribute to the disaster prevention and the shipping security and guarantee the people's life and safety.Research works were performed on the typical circulation of China Sea in summer and winter and Variation of South China Sea in the Interaction Process between Strong Tropical Cyclone and Ocean. At present, researching by the satellite data, buoy data, observation data and numerical simulation is main studying method of the above problems. Based on 3D and baroclinic ocean model POM2K, with forcing factors (terrain, water exchange, surface wind stress and thermal volume flux), China Sea circulation systems in summer and winter were simulated in the paper. The results show the good effects of the model which can provide the whole status of the circulation of the China Sea. Then based on the above improved model POM2K, a near reality ocean initial field was attained. Numerical simulation experiments were performed under the condition of a strong tropical cyclone named Vongfong (No.0214), by a two-way Mesoscale Coupled Model (MCMv1.0).The paper chooses the status of the China Sea in January and August representing the winter and summer circulation in the China Sea. With forcing factors (terrain, water exchange, surface wind stress and thermal volume flux), China Sea circulation systems in summer and winter were simulated in the paper. Quantitative analysis was taken on various physical factors of the experiments results.The summer simulation results show the whole status of the circulation of the China Sea, and indicates that, similar to the characteristics of west boundary current; Kuroshio appears anti-cyclonic bend when passing Bashi Channel (BC); the terrain and baroclinic effect are important to the 'West Side Current'; a cyclonic vortexappears on the north of the South China Sea (SCS) and a double vortex construction on south of the SCS.In winter, forced by the northeast monsoon and cold wave, there is surface coast water at two sides of China Sea, Korea West Coast and China Shelf Coast. The interaction between the Kuroshio and the shelf water is similar to summer. The Kuroshio and shelf mixing water induced by shear flow and continent sloping effect, moves northeast in the almost similar direction of Kuroshio, and get together forming a mixing water aggregation place. SCS is in the control of a larger scale cyclonic circulation, with two mesoscale ocean circulation in the north and south. After the researching work on the whole status of China Sea circulation system, based on the above improved model P0M2K, a near reality ocean initial field was attained. Numerical simulation experiments were performed under the condition of a strong tropical cyclone named Vongfong (No.0214), by a two-way Mesoscale Coupled Model (MCMvl.O). The results show that SST reduces heavily, the max-extent is about 4°C, with a greater reduction in the center and the right semicircle; Cool water pumping and the wind entrainment induced the reduction of the SST; the mixed layer deepened about 10-20m, whose area is obviously related to the SST changing area. A cyclonic vortex and water level fall appears on the sea surface, while storm surge occurs on the landing coast, with a 1.0m max increment. The results of Typhoon case (Rananim, No,0414) show that SST reduces heavily, the max-extent is about 4.5°C, with similar distribution; Cool water pumping and the wind entrainment induced the reduction of the SST, the extent and the scale of SST reducing increases as time, and the scale shape of the salinity reducing reflects the influent scale of Changjiang Diluted Water; the mixed layer deepened about 20-45m, whose area is obviously related to the SST changing area. A cyclonic vortex and water level fall appears on the sea surface, while storm surge occurs on the landing coast, with a 1.8m max increment.
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