Extraordinary subsurface mesoscale eddy detected in the southeast of Okinawa in February 2002

In February 2002, a subsurface mesoscale eddy with extraordinary features was detected at a depth of about 300 dbar in the southeast of Okinawa ( a part of the Ryukyu Islands). The water mass occupying this subsurface eddy is characterized as the North Pacific Subtropical Mode Water (NPSTMW) with salinity maximum and thick thermostad; its temperature, salinity and potential density at the core of the eddy are 18.4 degrees C, 34.81 and 25.06 sigma(theta), respectively. Thickness and width of the eddy are about 300 m and 100 km, respectively. Mixing between the eddy and the surrounding water mass is also found. Such eddy with the NPSTMW has never been detected during ten years.