On the origin of the Tsushima Warm Current Water

The origin of the Tsushima Warm Current Water (TWCW) in summer is studied mainly on the basis of the CTD data and the observations of satellite-traced surface drifters of Coastal Ocean Process Experiment of the East China Sea (COPEX-ECS) conducted by Korea Ocean Research and Development Institute.The main results are as follows: (1) The structures of the TWCW show obvious regional varitaions.The TWCW can be divided into three layers in the northern Okinawa Trough west of Kyushu and into two layers on the continental shelf and in the Tsushima/Korea Strait.(2) The surface TWCW,characterized by a sub-high salinity (33.5-34.10),comes mainly from the coastal water composed largely of the Changjiang Diluted Water,the surface Kuroshio water and the shelf water in the area south of the East China Sea (ECS).(3) The middle TWCW is sub-grouped into two parts: the water of salinity (S) larger than 34.50 located below the thermocline originates from the climbed sub-surface Kuroshio water;the TWCW lying in the thermocline is a mixture of the Kuroshio water and the shelf water with low salinity.(4) In the strait,the water from the source area is denatured obviously due to mixing unceasingly wth the shelf water and coastal water.The high salinity water of S > 34.5 appears only in the bottom layer with depths > 50m.