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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
Sato, Yosuke*; Sekiyama, Tsuyoshi*; Fang, S.*; Kajino, Mizuo*; Qurel, A.*; Qulo, D.*; Kondo, Hiroaki*; Terada, Hiroaki; Kadowaki, Masanao; Takigawa, Masayuki*; et al.
Atmospheric Environment; X (Internet), 7, p.100086_1 - 100086_12, 2020/10
The third model intercomparison project for investigating the atmospheric behavior of Cs emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident (FDNPP-MIP) was conducted. A finer horizontal grid spacing (1 km) was used than in the previous FDNPP-MIP. Nine of the models used in the previous FDNPP-MIP were also used, and all models used identical source terms and meteorological fields. Our analyses indicated that most of the observed high atmospheric Cs concentrations were well simulated, and the good performance of some models improved the performance of the multi-model ensemble. The analyses also confirmed that the use of a finer grid resolution resulted in the meteorological field near FDNPP being better reproduced. The good representation of the wind field resulted in the reasonable simulation of the narrow distribution of high deposition amount to the northwest of FDNPP and the reduction of the overestimation over the area to the south of FDNPP. In contrast, the performance of the models in simulating plumes observed over the Nakadori area, the northern part of Gunma, and the Tokyo metropolitan area was slightly worse.
Yamazawa, Hiromi*; Sato, Yosuke*; Sekiyama, Tsuyoshi*; Kajino, Mizuo*; Goto, Daisuke*; Morino, Yu*; Kondo, Hiroaki*; Qurel, A.*; Fang, S.*; Takigawa, Masayuki*; et al.
no journal, ,
Following the previous atmospheric transport model intercomparison project (MIP2), a new model intercomparison (MIP3) has been conducted in which, out of 12 models in MIP2, 9 models are participating. The main aim of MIP3 is to examine the effects of using a refined meteorological data with a finer horizontal resolution of 1 km. The horizontal distribution Cs-137 deposition in the eastern part of Honshu Island calculated by the models were compared with the aerial survey results to find that the simple ensemble average of the 9 models was a little worse than that of the 12-model ensemble in MIP2 statistically. However, in the sector in the northwestern direction from the accidental site, the deposition pattern by the MIP3 ensemble is more consistent with the survey result compared with that of MIP2. As for the atmospheric concentrations, although the model performance for the plumes that traveled over wider areas was slightly poorer for MIP3 than MIP2, the MIP3 ensemble generally showed better performance for the plumes that affected the near area in the Hamadori area. This better performance can be attributed to the better representation of topography in the meteorological simulation.
Sato, Yosuke*; Sekiyama, Tsuyoshi*; Sheng, F.*; Kajino, Mizuo*; Qulo, D.*; Qurel, A.*; Kondo, Hiroaki*; Terada, Hiroaki; Kadowaki, Masanao; Takigawa, Masayuki*; et al.
no journal, ,
no abstracts in English
Sato, Yosuke*; Takigawa, Masayuki*; Sekiyama, Tsuyoshi*; Kajino, Mizuo*; Terada, Hiroaki; Nagai, Haruyasu; Kadowaki, Masanao; Kondo, Hiroaki*; Uchida, Junya*; Goto, Daisuke*; et al.
no journal, ,
Two Model Intercomparison of Projects (MIPs) of atmospheric dispersion model targeting on Cs released from Fukushima Daiichi Nuclear Power Plant (FDNPP) on March 2011 were conducted. Both MIPs were conducted using an identical source term of Cs, identical meteorological data, and the same horizontal grid resolution (3 km and 1 km) to exclude the uncertainties of the model originated from them. Our analyses indicated that most of the model well simulated the atmospheric Cs obtained from the operational aerosol sampling of the national suspended particle matter network. Our analyses also indicated that meteorological data were most critical for reproducing the atmospheric Cs events, and the extent of the horizontal diffusion and the deposition were critical if the meteorological field was reasonably simulated. The comparison of the results between the two MIPs elucidated that the fine grid resolution is required to simulate atmospheric Cs in the vicinity of FDNPP, but the use of the fine grid resolution does not always improve the performance of the models especially for areas distant from the FDNPP. The results of both MIPs elucidated that the good performance of some models improved the performance of the multimodel, highlighting the advantage of using a multimodel ensemble.
Yamazawa, Hiromi*; Sato, Yosuke*; Sekiyama, Tsuyoshi*; Kajino, Mizuo*; Fang, S.*; Qurel, A.*; Qulo, D.*; Kondo, Hiroaki*; Terada, Hiroaki; Kadowaki, Masanao; et al.
no journal, ,
The 3rd model intercomparison project (MIP) of atmospheric dispersion model targeting on Cs emitted from Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 were conducted. All participated 9 models used the identical source term and meteorological data as in the previous MIP (2nd MIP), but finer horizontal grid resolution (1 km) than that of 2nd MIP (3 km) was used for understanding the behavior of atmospheric Cs in the vicinity of FDNPP. Results of the models elucidated that most of the observed high atmospheric Cs concentrations were well simulated, and the good performance of some models cancelled bad performance of some models when used as an ensemble, which highlights the advantage of multimodel ensemble. The analyses also indicated that the use of the finer grid resolution improved the meteorological field in the vicinity of FNDPP and the atmospheric Cs measured near FDNPP was more reasonably reproduced in 3rd MIP than 2nd MIP. As well as the evaluation of the performance of the model, we examined usefulness of the results of atmospheric dispersion simulation in an emergency. The analyses reported that the multimodel ensemble missed only 3% of the observed plumes, even if the absolute value of the simulated Cs in each model was different in the range of factor 3-6. The analyses also indicated that from six to eight models are required for making most of advantages of the multimodel ensemble.
Terada, Hiroaki; Nagai, Haruyasu; Tsuzuki, Katsunori; Kadowaki, Masanao
no journal, ,