Model Intercomparison of Atmospheric 137Cs From the Fukushima Daiichi Nuclear Power Plant Accident: Simulations Based on Identical Input Data
Model Intercomparison of Atmospheric 137Cs From the Fukushima Daiichi Nuclear Power Plant Accident: Simulations Based on Identical Input Data
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DOI：
10.1029/2018jd029144
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发表时间：
2018-10
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通讯作者：
Yousuke Sato;M. Takigawa;T. Sekiyama;M. Kajino;H. Terada;H. Nagai;H. Kondo;J. Uchida;D. Goto;D. Quélo;A. Mathieu;A. Quérel;Sheng Fang;Y. Morino;Pontus von Schoenberg;Håkan Grahn;N. Brännström;S. Hirao;H. Tsuruta;H. Yamazawa;T. Nakajima
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作者：
Yousuke Sato;M. Takigawa;T. Sekiyama;M. Kajino;H. Terada;H. Nagai;H. Kondo;J. Uchida;D. Goto;D. Quélo;A. Mathieu;A. Quérel;Sheng Fang;Y. Morino;Pontus von Schoenberg;Håkan Grahn;N. Brännström;S. Hirao;H. Tsuruta;H. Yamazawa;T. Nakajima
为了更详细地了解大气中铯- 137 （137Cs）的行为，对日本福岛第一核电站事故后排放的铯- 137 （137Cs）的大气扩散进行了模型比对。所有模式均采用具有良好时空分辨率和排放清单的相同气象数据，以排除因气象和排放数据差异而导致的模式差异。气象数据用于初始、边界和助推数据或离线气象场。此外，所有模式均采用与气象资料相同分辨率的水平网格。这种设置使我们能够关注源自每个模型中包含的过程的模型可变性，例如，物理过程。多模式集合捕获了观测到的大气137Cs事件的40%，137Cs总沉积在空间的功绩值超过80。大气137Cs值低于沉积137Cs值的主要原因是观测值与模拟值的时间差。我们的分析表明，气象资料是重现大气137Cs事件的最关键因素。结果进一步表明，在气象场模拟较好的情况下，不同模式间的137Cs浓度差异来源于沉积和扩散过程。沉降通量小的模式对大气137Cs的得分较高，扩散强度大的模式成功捕获了观测到的高137Cs浓度；然而，他们也倾向于高估浓度。
A model intercomparison of the atmospheric dispersion of cesium‐137 (137Cs) emitted after the Fukushima Daiichi Nuclear Power Plant accident in Japan was conducted to understand the behavior of atmospheric 137Cs in greater detail. The same meteorological data with a fine spatiotemporal resolution and an emission inventory were applied to all models to exclude the differences among the models originating from differences in meteorological and emission data. The meteorological data were used for initial, boundary, and nudging data or offline meteorological field. Furthermore, a horizontal grid with the same resolution as that of the meteorological data was adopted for all models. This setup enabled us to focus on model variability originating from the processes included in each model, for example, physical processes. The multimodel ensemble captured 40% of the atmospheric 137Cs events observed by measurements, and the figure of merit in space for the total deposition of 137Cs exceeded 80. The lower score of the atmospheric 137Cs than that of the deposition originated from the difference in timing between observed and simulated atmospheric 137Cs. Our analyses indicated that meteorological data were most critical for reproducing the atmospheric 137Cs events. The results further revealed that differences in 137Cs concentrations among the models originated from deposition and diffusion processes when the meteorological field was simulated reasonably well. The models with small deposition fluxes produced higher scores for atmospheric 137Cs, and those with strong diffusion succeeded in capturing the high 137Cs concentrations observed; however, they also tended to overestimate the concentrations.