Spatial Change of Salinity at Kuroshio in East China Sea with Seasons

Kuroshio influences hydrological-climate environment of East China Sea by exchanging heat and salinity. It has great influence on climate-environment in East China. Understanding of seasonal variability of salinity at Kuroshio in the East China Sea (ECS Kuroshio) can provide a scientific basis to reveal the climate-environment change in East China. In this paper, Using salinity database of World Ocean Atlas 2009(WOA09) issued by NOAA in 2010, the change of salinity distribution and the high-salt areas at ECS Kuroshio with seasons have been analyzed, the results show that: upper low-salinity water between 0 similar to 125m is obviously changing with seasons. From spring to winter, the horizontal stratification at upper low-salinity water first increases and then decreases, but the phenomenon of vertical mixing is opposite with the horizontal stratification. The horizontal stratification is the most obvious in summer, it forms 0.33/m of halocline strength above 10m; the vertical mixing is the strongest in winter, upper low-salinity water mixes with higher-salinity water in Okinawa trough, and salinity is homogenous in vertical above 250m. There are seasonal variations of depth and range of the high-salt areas in different segments along ECS Kuroshio, and there are three high salinity cores in the high-salt areas: two of the high salinity cores appear in the sea area east of Taiwan in autumn and winter, the third core appears in the sea area northwest of Miyako-jima in spring.