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Otosaka, Shigeyoshi
no journal, ,
Transport processes of particulate materials were inferred from elemental and isotopic proxies of seabed sediment, suspended particles and sinking particles collected in the Japan Sea between 1998 and 2008. The behavior of particles in the Japan Sea was summarized as follows; (1) lithogenic materials were supplied to the western regions via the atmosphere and to the eastern regions through the Tsushima Current, (2) the vertical sinking of particles occurred in spring due to remarkable biological productions in this season, (3) lithogenic particles act as ballast for the sinking of organic matters in the surface waters and it enhances the effect of the biological pump in the sea, (4) particulate fluxes were higher in the western regions, and (5) the lateral transport of particles along the abyssal slope was the dominant process in the eastern regions.
Takayama, Katsumi*; Watanabe, Tatsuro*; Kawamura, Hideyuki; Tanaka, Iori*
no journal, ,
Recently, researches of estimating a primary production are active by coupling an ocean general circulation model and a lower trophic level ecosystem model. This study aims to develop the vertically one-dimensional ecosystem model west of Hokkaido. The lower trophic level ecosystem model used in this study originates from the one-box NEMURO. It successfully reproduced spring and autumn phytoplankton bloom and maximum of phytoplankton concentration in the subsurface layer in summer.
In, Teiji*; Nakayama, Tomoharu*; Shima, Shigeki*; Ishikawa, Yoichi*; Awaji, Toshiyuki*; Kobayashi, Takuya; Kawamura, Hideyuki; Togawa, Orihiko
no journal, ,
A clockwise circulation called the Tsugaru gyre is formed from summer to autumn after the Tsugaru Warm Current passes through the Tsugaru Strait into the Pacific Ocean. This study aims to clarify a formation process of the Tsugaru gyre by a numerical model and observational data. It is suggested that a separation of the Tsugaru gyre from the coast is related to a strong southward current near the coast resulted from a penetration of the Oyashio to the Tsugaru Warm Current.
Kawamura, Hideyuki; Kobayashi, Takuya; Ito, Toshimichi; Otosaka, Shigeyoshi; Togawa, Orihiko; Onitsuka, Go*; Hirose, Naoki*
no journal, ,
Japan Atomic Energy Agency has been developing a material circulation model in the Japan Sea to confirm aspect of observational results. The material circulation model consists of three numerical models, an ocean general circulation model, a particle random-walk model and a lower trophic ecosystem model. A preliminary numerical experiment shows that vertical profile and total amount of Sr-90 and Cs-137 are well compared with observational results.
Aramaki, Takafumi*; Togawa, Orihiko
no journal, ,
no abstracts in English