Dynamics of radiocaesium within forests in Fukushima; Results and analysis of a model inter-comparison

Hashimoto, Shoji*; Tanaka, Taku*; Komatsu, Masabumi*; Gonze, M.-A.*; Sakashita, Wataru*; Kurikami, Hiroshi  ; Nishina, Kazuya*; Ota, Masakazu  ; Ohashi, Shinta*; Calmon, P.*; Coppin, F.*; Imamura, Naohiro*; Hayashi, Seiji*; Hirai, Keizo*; Hurtevent, P.*; Koarashi, Jun   ; Manaka, Takuya*; Miura, Satoru*; Shinomiya, Yoshiki*; Shaw, G.*; Thiry, Y.*

This study was aimed at analysing performance of models for radiocesium migration mainly in evergreen coniferous forest in Fukushima, by inter-comparison between models of several research teams. The exercise included two scenarios of countermeasures against the contamination, namely removal of soil surface litter and forest renewal, and a specific konara oak forest scenario in addition to the evergreen forest scenario. All the models reproduced trend of time evolution of radiocesium inventories and concentrations in each of the components in forest such as leaf and organic soil layer. However, the variations between models enlarged in long-term predictions over 50 years after the fallout, meaning continuous field monitoring and model verification/validation is necessary.