论文部分内容阅读
7Be是一种自然产生的放射性核素 ,由对流层和同温层大气中的氧和氮在宇宙射线作用下分裂生成 ,其半衰期为 53.3天。7Be通过连续的干湿沉降作用到达土表 ,被土壤颗粒紧密吸附 ,其土壤环境化学行为与137Cs相似 ,因此 ,可以用于示踪某种特定土地利用方式或侵蚀事件下的土壤侵蚀作用的强度、空间分配以及季节性变化。7Be技术可与其它反映中长期土壤侵蚀的放射性核素( 137Cs、2 10 Pb)示踪技术相结合 ,共同表征某个流域的土壤侵蚀状况。对7Be示踪技术现有的土壤侵蚀速率定量估算模型进行了简述 ,并提出了各自的局限性及今后的研究方向
7Be is a naturally occurring radionuclide produced by cosmic rays splitting oxygen and nitrogen in the atmosphere of the troposphere and stratosphere with a half-life of 53.3 days. 7Be reaches the earth’s surface through continuous wet-wet deposition and is closely adsorbed by soil particles. Its environmental chemical behavior is similar to that of 137Cs and therefore can be used to trace the intensity of soil erosion under a particular land-use pattern or erosion event , Space allocation and seasonal changes. The 7Be technique can be combined with other radionuclide (137Cs, 2 10 Pb) tracing techniques that reflect long-term soil erosion to characterize soil erosion in a watershed. The existing quantitative estimation models of soil erosion rate of 7Be tracer technique are briefly described and their respective limitations and future research directions are put forward