Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kawamura, Hideyuki; Kamidaira, Yuki; Kobayashi, Takuya
Journal of Nuclear Science and Technology, 57(4), p.472 - 485, 2020/04
Times Cited Count:3 Percentile:30.79(Nuclear Science & Technology)The Japan Atomic Energy Agency developed a Short-Term Emergency Assessment system of the Marine Environmental Radioactivity (STEAMER) to predict the oceanic dispersion of radionuclides in the ocean around Japan. The purpose of this study is to validate the predictability of STEAMER using oceanographic forecast and reanalysis data, which were saved for past several years. Results of oceanic dispersion simulations that are driven by oceanographic reanalysis data are assumed to be true solutions. Oceanic dispersion simulations are conducted for Cs-137 released hypothetically from the Fukushima Daiichi Nuclear Power Plant. The predictability of STEAMER is quantitatively examined for the length of the forecast period. Ensemble forecast simulations are also conducted to successfully improve the predictability of STEAMER.
Kawamura, Hideyuki; Furuno, Akiko; Kobayashi, Takuya; In, Teiji*; Nakayama, Tomoharu*; Ishikawa, Yoichi*; Miyazawa, Yasumasa*; Usui, Norihisa*
Journal of Environmental Radioactivity, 180, p.36 - 58, 2017/12
Times Cited Count:11 Percentile:34.92(Environmental Sciences)This study simulates the oceanic dispersion of Fukushima-derived Cs-137 by an oceanic dispersion model and multiple oceanic general circulation models. The models relatively well reproduced the observed Cs-137 concentrations in the coastal, offshore, and open oceans. Multiple simulations in the coastal, offshore, and open oceans consistently suggested that Cs-137 dispersed along the coast in the north-south direction during the first few months post-disaster, and were subsequently dispersed offshore by the Kuroshio Current and Kuroshio Extension. Quantification of the Cs-137 amounts suggested that Cs-137 actively dispersed from the coastal and offshore oceans to the open ocean, and from the surface layer to the deeper layers in the North Pacific.
Kawamura, Hideyuki; Kamidaira, Yuki; Kobayashi, Takuya
no journal, ,
The Japan Atomic Energy Agency developed a Short-Term Emergency Assessment system of the Marine Environmental Radioactivity (STEAMER). STEAMER is in daily test operation to predict the oceanic dispersion of radionuclides that are released into the ocean from nuclear facilities. The predictability of oceanic dispersion simulations is validated in this study. Oceanic dispersion simulations are performed for a hypothetical release of Cs-137 from the Fukushima Daiichi Nuclear Power Plant using oceanographic forecast and reanalysis data. Comparison between forecast and reanalysis simulations enables us to estimate the predictability quantitatively. Ensemble forecast simulations are also performed to improve the predictability. Moreover, a Regional Ocean Modeling System is applied to simulate ocean circulations accurately in the coastal and offshore areas. As a result, submesoscale eddies and tidal currents affect the oceanic dispersion of Cs-137.