Typhoon effect on Kuroshio and Green Island wake: a modelling study

Abstract

Abstract. Green Island located in the typhoon active eastern Taiwan coastal water is the potential Kuroshio power plant site. In this study, a high resolution (250–2250 m) shallow-water equations (SWEs) model is used to investigate the effect of typhoon on the hydrodynamics of Kuroshio and Green Island wake. Two wind induced flows, typhoon Soulik and Holland's wind field model, are studied. Simulation results of the typhoon Soulik indicate that salient characteristics of Kuroshio and downstream island wake seems less affected by the typhoon Soulik because typhoon Soulik is 250 km away Green Island and the wind speed near Green Island is small. Moreover, Kuroshio currents increase when flow is in the same direction as the counterclockwise rotation of typhoon, and vice versa. This finding is in favorable agreements with the TOROS observed data. The SWEs model, forced by the Kuroshio and Holland's wind field model, successfully reproduces the downstream recirculation and meandering vortex street. Numerical results unveil that the slow moving typhoon has a more significant impact on the Kuroshio and downstream Green Island wake than the fast moving typhoon does. Due to the counterclockwise rotation of typhoon, Kuroshio currents increase (decrease) in the right (left) of the moving typhoon's track. This rightward bias phenomenon is evident, especially when typhoon moves in the same direction as the Kuroshio mainstream.