Numerical model simulation of expansion of Changjiang diluted water in summer

A three-dimensional nonlinear baroclinic estuary and ocean model with primitive equation in σ-coordination system is developed to study the impacts of the factors of runoff, the Taiwan Warm Current (TWC) , the Huanghai Sea Cold Water Mass (HSCWM)and wind field on the expansion of Changjiang diluted water (CDW). Numerical experiments show the northeast expansion of freshwater tongue of CDW and the circulation structure of the East China Sea. Runoff has an effect only on the trend of southeast expansion of CDW and the extent of expansion. As greatly affected by topography, TWC has a stable flow path that is independent of its strength. And also because of the long distance of TWC from the Changjiang Estuary, TWC has a very little effect on the expansion of CDW. The residual current induced by HSCWM blocks the CDW's southward expansion along the coast. In sea area far from the Changjiang Estuary,HSCWM induces the CDW expand southeast. The HSCWM has a significant influence on the northeast turning direction of the CDW. The stronger the HSCWM is, the greater the effect of the HSCWM's induced residual currents and the more obvious the northeast turning of the CDW.