保健物理
Online ISSN : 1884-7560
Print ISSN : 0367-6110
ISSN-L : 0367-6110
原著論文
冬季日本海側における高空間線量率事象の解析
永井 英志山澤 弘実森泉 純平尾 茂一
著者情報
ジャーナル フリー

2018 年 53 巻 4 号 p. 219-229

詳細
抄録

A high environmental dose rate observed at Rokkasho-mura on December 17, 2015, which was reported to be caused by the wet deposition of radon decay products, was analyzed to depict its spatial distribution and to understand mechanisms of the unprecedentedly high dose rate increase of 0.151 µGy/h. It was pointed out that the high dose rate was observed widely on the Sea of Japan side of the main island of Japan, with areas of slight increases where the precipitation was light. It was also pointed out that the large increases corresponded with the precipitation intensity exceeding about 3 mm/h. However, precipitation events exceeding the value did not necessarily correspond to large increases of the dose rate. According to the analysis using a long-range atmospheric transport model and weather charts, the causal 222Rn was transported from the northeastern part of China and the southeastern part of Siberia, where existed a cold low pressure system transporting 222Rn vertically to form a 1 to 2 km-deep high concentration air layer. This air layer was transported by the winter monsoon to Japan without significant decay of 222Rn. It was found in this analysis that the large dose rate increase was observed at the locations where the significant level of precipitation occurred when the air layer existed.

著者関連情報
© 2018 日本保健物理学会
前の記事 次の記事
feedback
Top