科研之友
微信
新浪微博
Facebook
分享链接
摘要
The radiation monitoring network in the Netherlands is designed to detect and track increased radiation levels dose rate more specifically in 10-minute intervals The network consists of 153 monitoring stations Washout of radon progeny by rainfall is the most important cause of natural variations in dose rate The increase in dose rate at a given time is a function of the amount of progeny decaying which in turn is a balance between deposition of progeny by rainfall and radioactive decay The increase in progeny is closely related to average rainfall intensity over the last 2 5 h We included decay of progeny by using weighted averaged rainfall intensity where the weight decreases back in time The decrease in weight is related to the half-life of radon progeny In this paper we show for a rainstorm on the 20th of July 2007 that weighted averaged rainfall intensity estimated from rainfall radar images collected every 5 min performs much better as a predictor of increases in dose rate than using the non-averaged rainfall intensity In addition we show through cross-validation that including weighted averaged rainfall intensity in an interpolated map using universal kriging (UK) does not necessarily lead to a more accurate map This might be attributed to the high density of monitoring stations in comparison to the spatial extent of a typical rain event. Reducing the network density improved the accuracy of the map when universal kriging was used instead of ordinary kriging (no trend) Consequently in a less dense network the positive influence of including a trend is likely to increase Furthermore we suspect that UK better reproduces the sharp boundaries present in rainfall maps but that the lack of short-distance monitoring station pairs prevents cross-validation from revealing this effect.
- 出版日期2010-12-1
