~7Be法估算土壤侵蚀速率若干问题的探讨

发布时间：2018-03-15 23:26

本文选题：Be　切入点：土壤侵蚀　出处：《地球科学进展》2016年09期 　论文类型：期刊论文

【摘要】：~7Be是由宇宙射线撞击同温层和对流层大气中氮、氧原子核而生成的天然放射性核素。由于连续沉降、半衰期短(53.3天)以及在土层中分布深度浅(约2 cm)等特点,~7Be在示踪单次暴雨或短期强降雨等短时间尺度的侵蚀产沙空间分布研究中具有独特优势。随着气候变化加剧和暴雨等极端天气增多,~7Be法应用前景广阔。然而该技术目前处于探索阶段,一些重要基础假设尚未得到有效验证,限制了其在土壤侵蚀研究中的广泛应用。简要回顾了利用~7Be法定量土壤侵蚀速率空间分布的历史和现状,介绍了其示踪原理和计算模型及其最新进展;重点评述了~7Be法估算土壤侵蚀速率的关键基础假设及其不确定性,以及植被截留、侵蚀分选等对~7Be法评价土壤侵蚀速率的影响;并对未来研究趋势进行了展望,包括基础假设的验证及不确定性分析、植被影响的定量评价、示踪时空尺度的扩展以及新模型的开发等方面。
[Abstract]:7Be is a natural radionuclide produced by cosmic rays impacting nitrogen and oxygen nuclei in the stratosphere and troposphere. The characteristics such as short half-life (53.3 days) and shallow distribution depth (about 2 cm) have unique advantages in the study of spatial distribution of erosive sediment on a short time scale, such as single rainstorm or short term heavy rainfall. The application of the 7Be method is promising. However, the technology is still in the exploration stage. Some important basic hypotheses have not been validated effectively, which limits their wide application in soil erosion research. The history and present situation of spatial distribution of soil erosion rate by using 7Be method are briefly reviewed. In this paper, the tracer principle, calculation model and its latest progress are introduced, and the key basic assumptions and uncertainties of estimating soil erosion rate by means of 7Be method are reviewed, as well as the effects of vegetation interception and erosion sorting on the evaluation of soil erosion rate by the method. The trend of future research is prospected, including the verification of basic assumptions and uncertainty analysis, the quantitative evaluation of vegetation impact, the expansion of tracer space-time scale and the development of new models.
【作者单位】：中国科学院山地表生过程与生态调控重点实验室中国科学院水利部成都山地灾害与环境研究所;
【基金】：国家自然科学基金项目“粒度效应对137Cs、7Be法测算紫色土农耕地土壤流失量的影响”(编号:41301293) 国家重点基础研究发展计划项目“横断山地水土作用失衡机制与灾害风险评价”(编号:2015CB452704)资助~~
【分类号】：S157.1

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