| The main physical processes in the East China Sea include the Kuroshio and water flux of the Taiwan strait and Tsushima strait, the thermohaline structure and its seasonal variation by exchange of heat and water on sea surface and mixing of tide, as well as the tide and tidal current, and circulation and its seasonal variation. These processes control the distributions of oceanography factors and the transports of mass and energy in the East China Sea (ECS).Knowledge of the fluxes, velocity distributions and their variations in each of straits in the ECS were very important for study of the circulation and coastal environment in ESC. The OCCAM global ocean model results were applied to calculate monthly water transport through 4 main straits around ECS. Analysis results showed that annual mean flux in Eastern Taiwan was about 25.8Sv and the flux in summer was larger than that in spring and autumn, as well as smallest in winter. Annual mean flux in Togara Strait was about 27.9Sv and the flux in summer was larger than that in spring and winter, as well as smallest in autumn. Water always flowed from the South China Sea to the ECS in each season in the Taiwan Strait. The maximum flux was about 3.1Sv that appeared in July, and minimum was only 0.9Sv in November. The annual mean flux was about 2.0Sv. In the Tsushima Strait, the annual mean flux was 2.3Sv and its monthly variation just was only 0.4Sv.The thermocKne structure and its variation affected the circulation system in the ECS. The weekly and monthly mean sea surface temperatures (SST) in the ECS were obtained by analysis and calibration of SST data from satellites during 1990-1999. The character of monthly mean SST distribution in the ECS were descript in detail.The tide and tidal current were important processes in the ECS. A three -dimensional model, imbedded a closure turbulence sub-model, was built andapplied to simulate the barotropic tides and tidal currents in the ECS. Model results showed that tidal currents over the shelf from the continental edge to the entrance of the Yellow Sea rotated in a clockwise direction, while the currents in the Yellow Sea were rectilinear following and their direction of propagation along the coast. The semi-diurnal tidal ellipse showed three rectilinear regions that located in the middle of the Yellow Sea, the Bohai Strait and the Liaodong Bay.The studies of circulation in ECS were most based on the analysis of temperature and salinity data and diagnostic mode. Aim at breaking this limitation, we had established a quasi-predictive model in the ECS by reconstructing the POM model to overcome the difficulties brought to the simulations by steep terrain and great density gradient In the new model, the monthly mean SST data in the ECS and the result of global ocean model were used as the boundary conditions to simulate the distribution of the temperature and the circulation structure in the ECS. The analytical result showed that, the width of Kuroshio in the middle part became wider from south to north, and the velocity increased, and the depth of the core became shallow. In the northeast continental shelf in ECS, the Kuroshio intruded towards north in several branches in winter, while in summer, the Kuroshio intruded the northern shelf through continental marginal flow. The Taiwan warm current showed that an east and a north branches existing through the whole year, but the two branches showed obvious seasonal variations. In winter, the north branch had a lower speed and a narrower width, compared with that in summer, but the width of East branch was wider than that in summer. Huanghai warm current exist only in winter, which support the conclusion that it was a compensatory current under a strong north wind. The thesis has also done a systematical analysis on the sources and the seasonal variations of the warm currents in the ECS.The pattern an it seasonal variety of circulation in the Yellow Sea, significantly depended on distribution and vertical structure of temperature. In this paper, yearly cyclic...
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