Characteristics of Water Type Distribution and Seasonal Variations in the Southern East China Sea

By using the data of Summer and Winter 1987, Spring and Autumn 1988 obtained by the R/V " Shijian" during the China-Japan Joint Research Program on Kuroshio, the paper makes an analysis and research on the water type distribution and its variations in the studied sea area. Trie results of which are mainly as follows: (1) The Class IV mixing water whose property is similar to that of the continental coastal water is located in the northeast sea area, along the coast of the continent in autumn and winter while extending to the open sea in spring and summer. (2) The boundary between the Kuroshio water and the shelf mixing water (called the left boundary of the Kroshio water) is approximately located in between the 100m and 200m isobaths in various seasons and various layers, and mostly near the 200m isobath. In the sea area northeast of Taiwan, the Kuroshio water is to the west most in spring and then in winter. In summer, it is to the east most while, in autumn, it is in between its positions in summer

By using the data of Summer and Winter 1987, Spring and Autumn 1988 obtained by the R/V ' Shijian' during the China-Japan Joint Research Program on Kuroshio, the paper makes an analysis and research on the water type distribution and its variations in the studied sea area. Trie results of which are mainly as follows: (1) The Class IV mixing water whose property is similar to that of the continental coastal water is located in the northeast sea area, along the coast of the continent in autumn and winter while extending to the open sea in spring and summer. (2) The boundary between the Kuroshio water and the shelf mixing water (called the left boundary of the Kroshio water) is approximately located in between the 100m and 200m isobaths in various seasons and various layers, and mostly near the 200m isobath. In the sea area northeast of Taiwan, the Kuroshio water is to the west most in spring and then in winter. In summer, it is to the east most while, in autumn, it is in between its positions in summer and winter. At the bottom in summer and from surface to bottom in spring, the Kuroshio water mainly comes from the sea area to the northeast of Taiwan while part of it from the Taiwan Straits. Near the R1 , the intrusion of Kuroshio water into the shelf is the strongest in winter and the boundary is to the west; in summer, the intrusion is the weakest in the most cases and the authumn is in between the above two cases. (3) There is crisscross intrusion between the Kuroshio water and the shelf mixing water. The Kuroshio water is mingled with the mixing water of Classes I and II , while the shelf mixing water with isolating water of Kuroshio. (4) Along the continental slope, an upwelling phenomenon of Kuroshio water is often seen, but sometimes, slipping down of the shelf mixing water is also found to occur along the slope. (5) The water type distribution from southeast to northwest does not exactly follow the order of Classes K, I , II , III , and IV ; sometimes a transitional zone of water type may occur, its position varying with time and place.