Northwest Pacific Ocean Circulation And Its Impact On China's Coastal Circulation

The seasonal change of the circulation of Northwest Pacific and the circulation structure of Yellow Sea Cold Water Mass (YSCWS) in summer are studied with Modular Ocean Model (MOM2.O). In Chapter three the seasonal change of the circulation of Northwest Pacific is investigated. The annual forcing are used to integrate the model till 8 years. After that, monthly forcing are used to integrate the model for another 4 years when the seasonal equilibrium has reached for the upper layers. The model results show that: 1) The Volume Transport (VT) of Kuroshio changes in the East China Sea from 29.0 X 106m3/s in winter to 32.2 X I 06m3/s in summer, which is in contrast with the Sverdrup relation. One of the main cause of the seasonal change of VT of Kuroshio in the East China Sea is that there is seasonal changes of position of the zero-line of curl ~ (~ is the wind stress), which then cause the seasonal shift the bifurcation position of North Equator Current in the Phillippine Coast. 2) The comparison between the surface velocity in the East China Sea in summer and winter shows the intensification of the former, which is in consistence with the observation. 3) The Kuroshio east of Taiwan bifiircates into two branches: the main stream and eastern branch. The main stream flows northward into the East China Sea, and the eastern branch flows northeastward to the region east of Okinawa Islands. 4) The Smagorinsky scheme is capable to simulate the mesoscale phenomena. In Chapter four, based on the CTD data during July of 1997 from the cruise of China-Japan Cooperative Study on the Subtropical Circulation and the data of the same period of Global Temperature Salinity Profile Program (GTSPP) Real-time Data Sets, MOM2.0 is used to calculate the circulation for the 5 region of 21.8750 N~-?5.1250 N,120.8750 E~?37.1250 E. Both Diagnostic and Robust Diagnostic simulations are done. The result of Diagnostic simulations is more reliable. The main feature of the circulation 7 pattern in this season is as below: 1) The Kuroshio east of Taiwan does not split into two branches as usual. 2)The VT of Kurosbio in the East China Sea is about 30X 106m3/s. The VT south of Japan is about 70X 106m3/s. 3) There is a westward flow at 21.875 N~-?50 N comes from 137~ E with a VT of 15 X 1 06m3/s(SV). It splits into three branches south of Okinawa Islands, the main branch flows northeastward east of Ry黭y?guntO. 4) The Ry黭y? Current comes mainly from the above westward flow. In Chapter five theoretic solution of one dimensional heat transfer equation and a numerical simulation of 3D baroclinic circulation by MOM2.O are found to analyze the influence of bottom boundary mixing and the Topographic Heat Accumulation Effect (THAE) to the baroclinic structure of the YSCWS in summer. The vertical eddy viscosity of Yellow Sea is about 10條OOcm2/s. Our results show: 1) for different tidal mixing, the YSCWS shows different temperature distribution. Strong bottom boundary mixing makes the doming thermocline. The time scale of heat transfer is about a few days, while the circulation response in a longer time scale. 2) The circulation of YSCWS has a two4ayer structure. The circulation in the upper layer is cyclonic, while it is anticyclonic in the lower layer, and is thinner (about 10?0 meter) and weaker than the upper layer. The vertical integrated circulation is cyclonic. The strength of the bo...