Intercomparison of oceanic dispersion simulations on the Fukushima-derived Cs

Kawamura, Hideyuki  ; Furuno, Akiko   ; Kobayashi, Takuya ; In, Teiji*; Nakayama, Tomoharu*; Ishikawa, Yoichi*; Miyazawa, Yasumasa*; Usui, Norihisa*

Oceanic dispersion simulations include errors originated from source terms, oceanographic data, etc. In this study, the oceanic dispersion simulations were carried out with five oceanographic data in order to analyze an effect of oceanographic data on Cs dispersion and clarify Cs dispersion in the coastal area and the open ocean. The high-resolution simulation could well reproduce the observed Cs concentration in Fukushima Prefecture and it suggested that directly-released Cs into the ocean dispersed in the north-south direction during a few months after the Fukushima disaster. The relatively low-resolution simulations could reproduce main currents in the North Pacific and they suggested that the Kuroshio Extension played an important role on Cs transport from the coastal area to the open ocean. Moreover, it was demonstrated that Cs was transported from the mixed layer to the deeper layer 1 year after the Fukushima disaster.