Formation rate of water masses in the Japan Sea

Kawamura, Hideyuki  ; Yoon, J.-H.*; Ito, Toshimichi 

Water masses in the subsurface and intermediate layer are formed vigorously due to strong winter convection in the Japan Sea. Taking it into account that a part of pollutants is carried into the layer below the sea surface together with such water masses, it is significant to estimate a formation rate and turnover time of water masses to study a fate of pollutants. This study aims to estimate the formation rate and turnover time of water masses by using a three-dimensional ocean circulation model and particle chasing method. The total formation rate of water masses below the sea surface amounts to about 3.63 Sv in the Japan Sea. The formation rates of the Upper portion of the Japan Sea Proper Water (UJSPW) and Japan/East Sea Intermediate Water (JESIW) are estimated to be about 0.37 and 1.51 Sv, respectively. An estimate of turnover time shows that the UJSPW and JESIW circulate in the subsurface and intermediate layer with time scales of about 22.6 and 2.1 years, respectively.