Multiyear to daily radon variability from continuous monitoring at the Amram tunnel, southern Israel
Multiyear to daily radon variability from continuous monitoring at the Amram tunnel, southern Israel
复制标题
DOI：
10.1111/j.1365-246x.2010.04660.x
复制
发表时间：
2010-08-01
影响因子：
2.8
通讯作者：
Piatibratova, O.
中科院分区：
文献类型：
--
作者：
Barbosa, S. M.;Zafrir, H.;Piatibratova, O.
氡是一种天然存在的放射性惰性气体，由镭的α衰变在含铀岩石的矿物颗粒中产生。阿姆拉姆隧道（Amram Tunnel）布洛赫地球物理观测站）是一个特别适合调查氡变化的地点。该观测站位于阿拉瓦沙漠的干旱环境中，靠近埃拉特，构成观测站的170米隧道可以在沙漠环境和相当稳定的环境条件下进行氡监测。在阿姆拉姆隧道连续测量氡和环境参数的时间变化的分析，在几年的时间显示出一个复杂的时间模式，其特点是非平稳和多尺度功能。氡浓度表现出多年变化，其形式为平均值增加趋势类似于1000 Bq m（-3）yr（-1），而最大氡水平的趋势更大，最高可达2500 Bq m（-3）yr（-1）。氡浓度也显示出强烈的季节性模式，夏季最高，冬季最低，范围从冬季的2.5 kBq m（-3）到夏季的35 kBq m（-3）。季节内变化的特征是氡异常非常大，相对于基准面急剧增加超过20 kBq m（-3），发生在春季和夏季，并持续数天。日周期变化与午夜附近的最大值也出现在春季和夏季，在寒冷的月份缺席。氡在季节、季节内和每日时间尺度上的变化与隧道外的空气温度有关，特别是外部环境与进行测量的隧道内更稳定环境之间的温度梯度。
Radon is a naturally occurring radioactive noble gas generated within mineral grains of uranium bearing rocks by alpha decay from radium. The Amram tunnel (A. Bloch Geophysical Observatory) is a particularly suitable location for the investigation of radon variability. Located in the arid environment of the Arava desert, near Elat, the 170 m tunnel that constitutes the observatory enables radon monitoring in a desert environment and under fairly stable environmental conditions. The analysis of the temporal variability of continuous measurements of radon and environmental parameters at the Amram tunnel over a period of several years shows a complex temporal pattern characterized by non-stationary and multiscale features. Radon concentrations exhibit multiyear variability in the form of a increasing trend of similar to 1000 Bq m(-3) yr(-1) in the mean and much larger trends up to similar to 2500 Bq m(-3) yr(-1) in the maximum radon levels. Radon concentrations also display strong seasonal patterns, with maxima in summer and minima in winter, ranging from 2.5 kBq m(-3) in winter to 35 kBq m(-3) in summer. Intraseasonal variability is characterized by very large radon anomalies, with sharp increases of more than 20 kBq m(-3) relative to the base level, that occur in spring and summer and last for several days. Daily periodic variability with maxima around midnight appears also in spring and summer, being absent in the cold months. Radon variability at seasonal, intraseasonal and daily timescales is associated with the air temperature outside the tunnel, specifically the temperature gradient between the external environment and the more stable environment inside the tunnel where the measurements are performed.