Abstract
The Soya Warm Current（SWC）flows through a shallow strait between the Japan Sea and the Sea of Okhotsk. A surface cold belt with a subsurface doming structure forms offshore of the SWC axis. Mechanisms of the cold belt formation are discussed from a point of view of resonant interaction between a barotropic stratified flow and a shallow sill, and subsequent baroclinic adjustment along SWC. When a stratified current rides a slope upstream, the thermocline displaces upward greatly and outcrops owing to resonant generation of internal Kelvin waves if the upper layer is thinner than the lower layer. These upwelling features closely resemble those along the southwestern coast of the Sakhalin Island. SWC then flips from an upwelling-type to a downwelling-type structure, in doing so it transits from the west coast of Sakhalin to the east coast of Hokkaido. It is thistransition that leads to the offshore doming structure, which propagates downstream as a vorticity wave, manifesting the cold belt at surface.
