| 摘 要： | - The influence of salinity gradient on the velocity distributions in the Changjiang Estuary has been studied in consideration of gravitational circulation. It is shown by the results of calculation and analysis that there are two regions with the maximum values of both horizontal salinity gradient and gravitational circulation along the longitudinal direction of the Estuary, and the level of stratification is determined by the intensity of tidal turbulence. Values of Richardson Number and Internal Froude Number which represent the characteristics of salinity stratification in the Estuary have been given, and the relationship between them has been determined. Values of tidal diffusion component and shear diffusion component of the salt flux in the South Channel, the North Channel and the North Passage of the Changjiang Estuary have been calculated. It is shown that both components are closely related to the level of salinity stratification. Finally, the two-dimensional distribution of the vertical diffusion coefficient under salinity stratified conditions is discussed. It can be seen that the distribution of vertical diffusion coefficient is related to that of Richardson Number.
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