A Hydraulic Model of the Korea Strait Bottom Cold Current

A one and a half layer inviscid hydraulic model was introduced to study the dynamics of the flow that brings the bottom cold water southward into the Korea Strait. Two different channel geometries were considered; a rectangular channel and a channel with a sloping western wall, which represents the continental slope near the Korean coast. The lower layer water in the rectangular channel separates from the eastern wall when the depth of the channel, HO, becomes shallower than a critical value downstream. Hydraulic control of the flow is possible after the flow separation, if the channel becomes shallow enough. Before hydraulic control, the width of the flow decreases as HO decreases, but the effect of the slope of the western wall is negligible. After the control, however, the width increases as HO decreases or the slope becomes weaker. If the slope becomes weak enough or the channel becomes deep enough, which is determined by upstream conditions, the lower layer is observed only over the sloping western wall. This simple model shows that the continental slope between the East Sea (Japan Sea) and the Korea Strait makes the southward flowing North Korean Cold Water bank against the Korean coast in the Korea Strait. The model also shows that the sloping bottom near the Korean coast makes the bottom cold water of the Korea Strait appear only over the continental slope away from the trough of the strait. 1