全国γ辐射剂量率空间分布差异影响机理研究

Influencing Mechanism of Spatial Distribution Difference in National γ Radiation Dose Rate Based on Geographical Detector

γ辐射剂量率的监测是天然放射性水平调查的重要部分,其关系到公众健康和辐射环境安全。目前中国环境γ辐射剂量率的空间分布水平的评价多基于专家经验知识,该方法不能够定量化表达γ辐射剂量率与环境因子的相互作用关系。为了进一步了解中国环境γ辐射剂量率的空间分布水平及影响其分布的机理,基于地理探测器提出了定量表达γ辐射剂量率与环境因子的相互作用关系的方法。本文首先收集了2015年全国辐射环境自动监测站的空气吸收剂量率的数据,并计算了44个地级市的年均值作为被解释变量;然后探索性分析了44个地级市的γ辐射剂量率的空间分布的规律;最后结合环境要素指标,借助地理探测器方法揭示了全国辐射剂量率的空间分布影响机理。研究发现:(1)低值沿着中国黑河至南宁的沿线缓冲带分布,高值在该缓冲带两侧扩散。(2)环境要素中解释力由高到底排序为:海拔高程(0.846)>气候带(0.741)>植被覆盖(0.691)>土地利用分类(0.427)>生态系统(0.419)>地形(0.101)。海拔高程一方面通过表观地球营力与地质构造,从而影响着地壳中天然辐射水平;另一方面对通过对自然环境的分布情况的影响,决定着人类生产活动的分布,进而作用到人工电离辐射源。因此影响γ辐射剂量率的空间分布的主要环境因子是综合了自然要素与人文经济活动的海拔高程。

The monitoring of γ radiation dose rate is an essential part in the field of natural radioactivity level research. In addition, it relates to the public health and radiation environment safety. The evaluation methods of spatial distribution level are mostly based on expert experience knowledge, which cannot explicitly express the quantitative relationship between the γ Radiation dose rate and the environmental factors. In order to understand the spatial distribution and the influencing mechanism of γ Radiation dose rate, we proposed a new evaluation method of revealing the environmental influence mechanism of ）, Radiation dose rate, based on geographical detector （Geogdetector）. A total of 6 environmental factors were selected for the evaluation of spatial distribution of γ Radiation dose rate, including the elevation, ecology, topography, climate, vegetation, and LUCC. Firstly, we collected the data of automatic monitoring station of national radiation environment in 2015, and calculated the annual average value in each city. Then, we studied the spatial distribution of γ Radiation dose rate in 44 cities to discover the spatial pattern. Finally, we used the geographical detector to reveal the environmental influence mechanism of γ radiation dose rate. The results show that： （1） the spatial distribution of γ radiation dose rate in China has the following pattern： the low value distribute along the buffer zone from the city Heihe to Nanning, the high value distribute on both sides of the buffer zone. （2） The explanatory power of environmental factors is sorted into： Elevation （0.846） 〉Climate （0.741） 〉Vegetation （0.691） 〉LUCC（0.427） 〉Ecology （0.419） 〉 Topography （0.101）. On the one hand, the elevation works through the appearance of the geological structure to influence the crust in the natural radiation level. On the other hand, through the impact of the distribution of the natural environment, the elevation also determines the distribution of human activities, and the role of artificial ionizing radiation source. Therefore, the distribution of γ radiation dose rate was significantly affected by elevation classification, which is comprehensively considered as the human economic factors and the natural environment factors.