Abstract: This paper took the Zhejiang coast as the research domain and a 3D baroclinic nonlinear numerical model was used to simulate coastal upwelling on the basis of special topography along Zhejiang coast, with some variable dynamic factors, such as wind, Taiwan Warm Current, tides, and Changjiang runoff, taken into account. The results show that upwelling in banding shape occurs along Zhejiang coast in spring, with the strong upwelling centers occurring near Yushan Islands(28.40°N, 122.00°E) and Zhoushan Islands(30.70°N,122.60°~123.00°E). The wind, Taiwan Warm Current, and tides are main inducements of upwelling. The wind and Taiwan Warm Current influence entire upwelling band. Tides affect the two strong upwelling centers and the upwelling between 28.60°N and Zhoushan Islands, which parallels the Zhejiang coast. Changjiang runoff affect the upwelling near Zhoushan Islands, Changjiang Estuary and the two centers of upwelling.The dynamic cause of currents demonstrates that onshore velocities at the bottom depth contours of 20 m, 30 m, and 50 m near Zhoushan Islands are bigger than those surrounding areas. The phenomenon of upwelling is obvious. For the upwelling near Zhoushan, Coriolis force, horizontal advection, and vertical viscous force are main driving mechanisms of upwelling within 20~30 m. Coriolis force and pressure gradient force are main forcing factors below 30 m, while horizontal advection and vertical viscous force are weak.

Key words: Zhejiang coast, upwelling, Regional Ocean Modeling System(ROMS), dynamic cause