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Moriguchi, Yuichi*; Sato, Yosuke*; Morino, Yu*; Goto, Daisuke*; Sekiyama, Tsuyoshi*; Terada, Hiroaki; Takigawa, Masayuki*; Tsuruta, Haruo*; Yamazawa, Hiromi*
KEK Proceedings 2021-2, p.21 - 27, 2021/12
no abstracts in English
Terada, Hiroaki; Nagai, Haruyasu; Katata, Genki; Tsuzuki, Katsunori; Akari, Shusaku*
no journal, ,
During the Fukushima Daiichi Nuclear Power Station accident which is necessary for accurate estimation of doses to the public, atmospheric dispersion simulations were conducted by using an atmospheric dispersion model underdevelopment Japan Atomic Energy Agency. The simulations were done by a latest meteorological model WRF and a particle dispersion model GEARN which has detailed deposition scheme considering different chemical forms. Surface deposition distribution in east Japan measured by airborne survey was largely reproduced by the simulation using the four-dimensional variational assimilation method (4D-Var) with meteorological observation data near the site and the latest estimated source term. Hereafter, we aim to estimate more accurate source term based on the comparison with the measurements such as air concentrations of 
Cs, etc.
Cs due to the Fukushima Daiichi Nuclear Power Station accident based on the intercomparison of atmospheric dispersion modelsMorino, Yu*; Kitayama, Kyo*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
no journal, ,
For the evaluation of the validity and variability of atmospheric transport model results, we compared results of seven models submitted for the model inter-comparison project of Science Council of Japan to simulate Cs released from the Fukushima Daiichi Nuclear Power Plant. Model reproducibility was assessed with the observed hourly atmospheric concentrations of Cs in Tohoku and Kanto regions. Among nine plumes from 12 to 21 in March 2011, performance of the models was the best for the plume which dispersed over the Kanto region in 15 March. The models generally reproduced the observed Cs concentrations in plumes which widely spread inland of Tohoku or Kanto regions. By contrast, the models largely underestimated the observed Cs concentrations for the case which passed coastal areas of Japan. Ensemble average of seven models showed reasonable performance for most of plumes, and no individual models reproduced better than the ensemble average.