Three-dimensional Baroclinic Numerical Model Of Current And Salinity In Yangtze Estuary

This paper presents a series of numerical models and simulated results of Yangtze Estuary. First of all, 3-D nonlinear baroclinic current and salinity numerical models with vertical cr coordinate were derived. 2-D, 3-D barotropic, 3-D baroclinic-diagnosis and 3-D baroclinic-prediction numerical models of Yangtze Estuary were established, in which vertical eddy coefficient was obtained from the advanced K-KL turbulence closure model. Based on analysis and comparison of results, it was discussed on choosing of current and salinity numerical models.Water and land boundary conditions for numerical models of Yangtze Estuary were dealt especially. Water level process obtained from tidal wave model of China East Sea was used as open water boundary condition of Yangtze Estuary models, which ensures simulated tidal current feature in Yangtze Estuary consistent with that in China East Sea. It is indicated that runoff at upstream section should be used as velocity boundary condition. If no field data of boundary runoff available, the "runoff process magnifying method" presented is suggested, which ensures the facticity of boundary runoff. Wetting and drying boundary condition in 3-D model was dealt with the idea of "wetting and drying method" in 2-D model, which ensures the simulation stability with longer time step and also widens the application area of 3-D model in shallow water zone.2-D and 3-D residual currents in Yangtze Estuary were simulated with tracking method of water particles, and macro characteristic of residual current was presented. The effects of runoff, wind and water density gradient on Lagrange residual current were simulated and analyzed. It's the first time to analyze the simulated current and Lagrange residual current fields obtained from a series of models systemically.Error Back-Propagation Neural Network (BP Neural Network) method was used to predicate Salinity Intrusion in estuary for the first time, and the predicated results are satisfying. It not only widens research ideas and approaches on Salinity Intrusion in estuary, but also improves predication efficiency.