Direct measurements of surface and mid-depth circulation in the Shikoku Basin by Argo profiling floats
1.Institute of Marine Environment, Ocean University of China, Qingdao 266100, China
2. Second Institute of Oceanography, SOA Hangzhou 310012.
3. key Lab of Ocean Dynamic Processes and Satellite Oceanography, SOA Hangzhou 310012
Abstract: The circulation in the Shikoku Basin plays a very important role in the pathway of the Kuroshio and the water exchange in the subtropical gyre in the North Pacific Ocean. The Argo profiling floats deployed in the Shikoku Basin are used to study the circulations and water masses in the basin. The trajectories and parking depth velocity fields derived from all Argo floats show an anticyclonic circulation at 2 000 m in the Shikoku Basin. There are inhanced eddy activities in the Shikoku Basin, which have large influence on the Shikoku Basin circulation patterns. The characteristics of temperature - salinity curves indicate that there are North Pacific Ocean tropical water （NPTW）, North Pacific Ocean subtropical mode water （NPSTMW） and North Pacific Ocean intermediate water （NPIW） in the Shikoku Basin. The NPTW is only exists south of 32°N. In the middle part of the basin, which is 28°～31°N,133°～135°E, there is a confluence region. Water masses coming from the Kuroshio mix with the water in the Shikoku Basin.
Key words: Argo,Kuroshio,anticyclonic eddy;mid-depth current,water mass,Shikoku Basin