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Takayama, Katsumi*; Hirose, Naoki*; Kawamura, Hideyuki; Shimizu, Daisuke*; Watanabe, Tatsuro*
no journal, ,
An ocean general circulation model in the Japan Sea has been being developed to reproduce and forecast movement of pollutants at JAEA. It was demonstrated that an assimilation of sea level variation at tide stations along the Japanese coast is effective to reproduce oceanic condition in the nearshore region. In this study, an effect of assimilation of satellite altimeter data, CTD data and tide data is quantitatively surveyed. As a result, it was demonstrated that this assimilation scheme improves the oceanic condition.
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.
Watanabe, Tatsuro*; Takayama, Katsumi*; Kawamura, Hideyuki; Tanaka, Iori*
no journal, ,
Based on an operational ocean forecast system, a one dimensional lower trophic ecosystem model was applied for understanding seasonal and vertical variations of the primary production in the northern Japan Sea. The ecosystem model successfully showed realistic seasonal variations and their vertical distributions of nitrate, phytoplankton and zooplankton. For example, the spring bloom occurred with approximately 1.5
10
molN/l in early April from the surface to the depth of 50 m.
Takayama, Katsumi*; Watanabe, Tatsuro*; Kawamura, Hideyuki; Tanaka, Iori*
no journal, ,
A three-dimensional lower trophic ecosystem model is applied to understand temporal and spatial variation of chlorophyll-a and nutrient in the Japan Sea. The lower trophic ecosystem model is driven by monthly solar radiation and daily temperature, current velocity and vertical diffusion coefficient calculated from the eddy-resolving ocean general circulation model. Satellite data of SeaWiFS on chlorophyll-a concentration at sea surface and long-term bimonthly data in the northern Japan Sea are used to validate model results. The lower trophic ecosystem model qualitatively reproduced seasonal variation of chlorophyll-a and nutrient. Spatial averages of correlation coefficient and RMS between the model results and the satellite-observed chlorophyll-a are 0.455 and 1.468 mg/m
, respectively.
Takayama, Katsumi*; Watanabe, Tatsuro*; Kawamura, Hideyuki
no journal, ,
Variation of chlorophyll-a is analyzed with three-dimensional lower trophic ecosystem model in this study. The lower trophic ecosystem model is driven by daily temperature, current velocity, and vertical diffusion coefficient and monthly solar radiation. Satellite data on chlorophyll-a concentration by MODIS/AQUA and chlorophyll-a concentration observed at PM line by Japan Meteorological Agency are used to validate model results. It is found that spatial average of correlation coefficient of chlorophyll-a concentration between model and observation is 0.403 and the correlation coefficient is comparatively low in the southwestern Japan Sea. The lower trophic ecosystem model qualitatively reproduced year-by-year variation of chlorophyll-a concentration as well as seasonal variation.