Study on the currents in Lake Biwa (II)

Abstract

Some numerical experiments are made using a linear barotropic model of Lake Biwa to investigate the current induced by the spatially uniform wind stress. Concerning the phenomena whose time scale is longer than the inertial period, we integrate the non-divergent vorticity equation.

It is found that the “topographic curl” of the wind stress which comes from the bottom topography and the wind stress induces circular currents and that the current, generated by the wind, attenuates gradually accompanying the topographic Rossby wave whose period is about 9 half-pendulum days in Lake Biwa. This mechanism of the barotropic response of the lake water to the wind will explain well the unsteady lake current in Lake Biwa in winter.