[3J09-12] Fukushima 2

[3J12] Investigation on distribution of radioactive substances in Fukushima

(12) Modeling the effect of soil moisture content on the change of air dose rate in forests in Fukushima Prefecture

*Miyu Nakanishi¹, Yuichi Onda¹, Hiroaki Kato¹, Junko Takahashi¹ (1. University of Tsukuba)

Keywords:Air dose rate, Soil moisture content, Effective rainfall

In this study, soil moisture and air dose rate were investigated in several forests in Fukushima Prefecture, with the aim of estimating changes in air dose rate using effective rainfall (Rw), which represents soil moisture status. Field observations showed a negative correlation between soil moisture and air dose rate. The decay rate of air dose rate was also found to be related to the 137Cs concentration in the surface soil. Effective rainfall not only combined half-lives of a few hours and days, but also differentiated between water absorption and drainage processes, which made it possible to reproduce soil moisture and air dose rate. This leads to the possibility of removing the influence of rain on measured air dose rate data.