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土壤侵蚀是关系人类生存与可持续发展的重大环境问题。20世纪60年代以来,Cs-137作为一种人工放射性示踪核素,被广泛应用于土壤侵蚀及堆积研究。而准确估算区域Cs-137背景值(Cs-137 Reference Inventory,CRI)是应用Cs-137开展土壤侵蚀研究的前提条件,其结果直接影响土壤侵蚀速率结果的准确性和可靠性。基于现有文献资料中获取的中国大陆102个CRI实测数据,以及全球降水气候中心提供的降水量再分析资料(空间分辨率2.5°×2.5°、0.5°×0.5°,1981-2010年),在借鉴Walling&He模型(Walling&He Model,WHM)和Michio Aoyama模型(Michio Aoyama Model,MAM)的基础上,本文建立了中国大陆CRI修正模型(Modified CRI Model for the Mainland of China,MCM),并利用Kriging/Cokriging插值方法计算了中国大陆CRI的空间分布。模型评估与对比分析表明,MCM模拟值与实测值大致吻合,且总体高于WHM和MAM模拟值,MCM能对中国大陆CRI进行较高分辨率、较高精度的模拟。模拟结果显示,中国大陆CRI的范围为141~12123 Bq/m2,在东北及新疆局部地区达到最大值,最小值主要集中于25°N以南地带。除新疆局部地区外,中国大陆CRI分布整体呈现自西向东,同纬度地区随降水量增加而增加的特点,而纬向上主要呈现随纬度增加而增加的特点。此外,大尺度大气流场、再悬浮过程、局部核试验等因素增加了中国大陆CRI分布的不均匀性。
Soil erosion is a major environmental issue that is related to human survival and sustainable development. Since the 1960s, Cs-137 has been widely used in soil erosion and accumulation studies as an artificial radioactive nuclide. Accurately estimating the Cs-137 Reference Inventory (CR-137) is a prerequisite for applying Cs-137 to soil erosion research. The results directly affect the accuracy and reliability of soil erosion rate results. Based on the 102 CRI data obtained from the existing literature and the reanalysis data of precipitation provided by the Global Precipitation and Climate Center (spatial resolution of 2.5 ° × 2.5 °, 0.5 ° × 0.5 °, 1981-2010) Based on the Walling & He Model (WHM) and the Michio Aoyama Model (MAM), the CRI Model for the Mainland of China (MCM) was established and the Kriging / The Cokriging interpolation method calculates the spatial distribution of CRI in mainland China. The model evaluation and comparative analysis show that the simulated values of MCM agree well with the measured values, and they are generally higher than the values of WHM and MAM. MCM can simulate the CRI of Chinese mainland with higher resolution and higher accuracy. The simulation results show that the CRI of the Chinese mainland ranges from 141 to 12123 Bq / m2, reaching the maximum in the northeast and part of Xinjiang, with the minimum concentrating mainly in the south of 25 ° N. Except for some areas in Xinjiang, the distribution of CRI in Mainland China showed an overall increase with increasing precipitation from west to east and in the same latitude. However, the latitudinal distribution of CRI mainly showed an increase in latitude. In addition, large-scale atmospheric flow field, resuspension process, local nuclear test and other factors increase the inhomogeneity of CRI distribution in China.