Copyright © The Oceanographic Society of Japan. Significance of Shallow Bottom Friction in the Dynamics of the Tsushima Current

A simple analytical model is considered for the dynamics of volume transport of the Tsushima Current. This model is basically baroclinic but allows bottom friction over the shallow regions connecting the Pacific Ocean to the Japan Sea basin, and is thus different from previous models which are either purely barotropic with bottom fric-tion predominating over the whole domain, or purely baroclinic with bottom friction completely ignored. Compared to the previous barotropic model, this model is not only more realistic but also gives much simpler results. It gives the observed down-stream sea level slope, which is not seen in the previous baroclinic model. As a result, the estimated transport of the Tsushima Current is closer to the observational data than those of previous models. This model indicates that the localized bottom friction acting over the shallow regions not only controls the transport of the Tsushima Cur-rent but also moves the stagnation point of the western boundary current northward. of oceanic water. On the other hand, Lie and Cho (1994) indicate that the branching of the Kuroshio or the origin of the Tsushima Current takes place near the eastern sid