The Simulation on seasonal variation of the Tsugaru Warm Current by the ocean forecasting system off Rokkasho village

In, Teiji*; Nakayama, Tomoharu*; Matsuura, Yasutaka*; Shima, Shigeki*; Ishikawa, Yoichi*; Awaji, Toshiyuki*; Kobayashi, Takuya ; Kawamura, Hideyuki  ; Togawa, Orihiko 

An oceanic forecasting system for coastal area near Rokkasho village has been developed. A circulation in this area is primarily controlled by the seasonally-varying Tsugaru Warm Current and the Oyashio. Previous observations suggest that seasonal variation in this region is characterized by two different modes: the coastal mode in cold seasons and the gyre mode in warm seasons. To attempt the accurate forecast, a downscaling method is an effective approach because it enables us to use a high resolution 4-dimensional variational data assimilation system. Model results realistically reproduced the seasonal variation of the Tsugaru Warm Current and the Oyashio from May in 2003 to January in 2004.