| The South China Sea (SCS) is a semi-enclosed marginal sea in the western North Pacific Ocean. The circulation of the northern SCS is strongly influenced by the Kuroshio, the western boundary current of the North Pacific, which frequently intrudes into the northern SCS through the Luzon Strait, the only deep passage connecting SCS to the open Pacific. The intruded Kuroshio moves westward and collides with the Dongsha Islands off the China coast. The collision forces most of the flow to return as a strong return flow to the north and a splinter current to the southwest along the upper continental slope. The return loop occasionally spawns anti-cyclonic rings which are instrumental in transporting tropical heat and salt into the northern SCS. The splinter current, on the other hand, feeds a northeastward shelf-break current that arises due to the alongshore pressure variation imposed offshore by the collision action, at the Dongsha Islands, of the intruded Kuroshio. The dissertation provides a dynamic explanation of the occasional current ring formation in terms of a mass-imbalance that can be found in current loops in general. It explains, in the absence of rings, the dynamics for the year-round existence of the northeastward shelf-break current (the so-called South China Sea Warm Current) in terms of the pressure imposed offshore due to the Kuroshio collision with the continental slope. In addition, the dissertation also demonstrates, albeit with a numerical model, the fact that the splinter current (the so-called South China Sea Branch of the Kuroshio (SCSBK)) feeds the northeastward shelf-break current all along the shelf-break, making the latter a warm current. |
