洮河流域径流输沙演变与降雨及降雨侵蚀力的关系

目的]揭示气候变化、人类活动耦合作用下复杂的水沙变化、水沙关系，探明降雨侵蚀力的影响及径流输沙变化的响应机理，为流域水土流失防治和生态建设提供科学参考依据。方法]基于洮河流域及周边6个气象站点逐日降水和下游控制站逐月径流输沙数据，采用多元统计分析法、水沙曲线、相关系数、灰色关联度、弹性分析法等方法分析研究了径流、输沙、降雨(P)、降雨侵蚀力(R)演变规律，及其相互作用关系。结果]洮河流域1956—2019年径流整体呈显著下降趋势，线性变化率-2.8×10⁷m³/a, 1987年发生突变，输沙整体呈显著下降趋势，线性变化率-4.61×10⁵t/a, 2003年发生突变，降雨、降雨侵蚀力均呈不显著上升趋势，且未出现明显突变。洮河流域R上中游小于下游，夏季(626.33)>秋季(125.31)>春季(122.22)>冬季(0),夏季降雨侵蚀力占比71.67%,夏季对泥沙侵蚀影响最大。P与R分布相反，P相对较小的下游流域R较大，P相对较大的上中游R较小，流域水沙异源，上中游产水，下游产沙。对输沙量影响最大...

Relationship Between the Evolution of Runoff and Sediment and Rainfall and Rainfall Erosivity in the Taohe River Basin

Objective] The aim of this study is to reveal the complex changes of water and sediment and the relationship between water and sediment under the coupling effect of climate change and human activities, as well as the influence of rainfall erosivity and the response mechanism of runoff and sediment transport changes, and then to provide scientific reference for water and soil loss prevention and ecological construction in the basin. Methods] The daily precipitation data of six meteorological stations in Taohe River Basin and its surrounding areas and monthly runoff and sediment data of downstream control stations were used. Multivariate statistical analysis method, water-sediment curve, correlation coefficient, grey correlation degree and elastic analysis method were used to analyze and study the variability of runoff, sediment, rainfall (P) and rainfall erosivity (R) and their interaction relationship. Results] The runoff in Taohe River Basin decreased significantly from 1956 to 2019 with the linear change rate of -2.8×10⁷m³/a and the abrupt change occurred in 1987. The sediment decreased significantly with the linear change rate of -4.61×10⁵t/a and the abrupt change occurred in 2003. The rainfall and rainfall erosivity did not increase significantly without obvious mutation. R in the upper and middle reaches of Taohe River basin was less than that in the lower reaches with R in summer(626.33)>R in autumn(125.31)>R in spring(122.22)>R in winter(0), and R in summer was 71.67% and the influence of rainfall erosivity in summer was the greatest. The distribution of P and R was opposite. R was greater in the lower reaches of the basin where P was relatively little, and R was less in the upper and middle reaches of the basin where P was relatively great. Runoff and sediment were generated in different part of the basin with runoff producing in the upper and middle reaches and sediment producing in the lower reaches. R had the greatest influence on sediment, when P had the greatest influence on runoff. The sediment caused by unit rainfall erosivity had been decreased since 2003. Human activities that affected the sediment accounted for about 90%, and climate factors accounted for 10%. Conclusion] The sediment in the Taohe Basin is mainly influenced by human activities under the changing environment, and the runoff and sediment in the basin have different sources. Compared with P, more attention should be paid to the effect of R on the sediment change.