东沙群岛西南冷涡的海水理化特性

PHYSICAL CHEMICAL CHARACTERISTICS OF SEAWATER IN THE COLD EDDY SOUTHWEST OF DONGSHA ISLANDS

东沙群岛西南海区的溶解氧、活性磷酸盐和活性硅酸盐100m层四季的平面等值线出现封闭或半封闭的分布,表明了该海域气旋型涡旋的终年存在,溶解氧饱和度的断面分布也证实了东沙群岛西南海域终年存在下层海水抬升,并表明冷涡轴随深度增加而向东南方向倾斜。温度、盐度、溶解氧.活性磷酸盐在表层都有一均匀层,次表层有一跃层,而深层值则季节变化不大。

In the sea area southwest of Dongsha Islands, there occurs an enclosed or semi-enclosed distribution of dissolved oxygen,active phosphate and active silicate at the 100m layer of isoline level, during the season of spring, summer, autumn and winter. This shows that there is a cyclone eddy in this area throughout the year. The profile distribution of dissolved oxygen saturation degree also proves that there exists a rising of the lower layer seawater in the sea area southwest of Dongsha Islands throughout the year, and the axis of the cold eddy slopes down to the southeast with the increase of water depth.An uniform layer exists at the surface layer for temperature, salinity, dissolved oxygen and active phosphate, there is a cline at the sub-surface layer, while their values in the deep layer show few seasonal variation.