Interactions Of Ocean Mesoscale Eddies And The Beginning Of The Kuroshio

The Kuroshio is a high-temperature, high-salt and high-velocity western boundary current of the North Pacific Subtropical Gyre. It originates at the east of the Philippines, and flows from the east of Taiwan Island, continental shelf of the East China Sea, Tokara Strait to the Pacific.A part of the western boundary current from the east of Luson Island to the Taiwan Island is named as the beginning of Kuroshio. When the Kuroshio flows to the Luzon Strait, it maybe deform and penetrate into the South China Sea(SCS). Then the Kuroshio exchanges the mass,momentum and energy with the SCS at the Luzon Strait and influence the circulation of the SCS. Thus, it has important significance to study the key process and dynamic mechanism of the Kuroshio penetration into the SCS.In my dissertation, I used the altimeter data and high-resolution numerical model output to analyse the upper circulation characters of the northeast of SCS and the eastern of the Luzon Island. Then I established a 1.5-layer reduced-gravity shallow-water model to analysis the nonlinear characters of the Kuroshio penetration into the SCS and the interaction between the ocean middle-scale eddies and the beginning of the Kuroshio at the Luzon Strait.Firstly, the analyses of altimeter data and high-resolution numerical model output shows that monsoon is the major factor of northern SCS upper circulation. Then the Kuroshio penetration into SCS also affects the northern South China Sea circulation features as an important factor. Secondly, using a ideal numerical model, we find that the kuroshio penetration into the SCS exits nonlinear characters, such as the steady state, bifurcation, period-solution, corresponding with multiple states such as loop current, rings, leap and so on. Finally, we discuss the interaction between the ocean mesoscale eddies and the beginning of the Kuroshio at the Luzon Strait. Results show that when the ocean mesoscale eddies moving westward and encountering the Kuroshio at Luzon Strait, they usually dissipate or move northward with the Kuroshio. But when the Kuroshio is weak, the eddies maybe transfer the energy from the Pacific to the SCS.