【摘要】 气候变化和人类活动是影响河川径流、输沙变化的主要原因。笔者基于渭河流域23个气象站1961—2015年日降雨量数据和水文站年输沙量资料,采用Mann-Kendall非参数性检验、双累积曲线和克里金插值等方法,对近55年以来渭河流域的降雨侵蚀力和输沙量的动态变化进行分析。结果表明:1)渭河流域近55年的平均降雨侵蚀力为1 685. 67 MJ·mm/(hm~2·h·a),研究时段内的降雨侵蚀力增加趋势不显著。2)渭河流域降雨侵蚀力的分布范围为292. 9～4 098. 9 MJ·mm/(hm~2·h·a),降雨侵蚀力的空间差异较大。流域多年平均降雨侵蚀力自东向西,由南向北呈逐渐减小趋势。3)渭河流域输沙量受降雨侵蚀力和人类活动共同影响:张家山站和咸阳站在20世纪90年代以后,人类活动对输沙量的影响较大,贡献率均> 100%。状头站在1980—1994年期间,人类活动的贡献率达到58%,进入21世纪以来,人类活动贡献率达到67%。本研究定量评价了渭河流域输沙量变化及对降雨侵蚀力和人类活动的响应,为未来区域水土保持措施配置、流域综合治理提供基础依据。更多还原

【Abstract】 [Background]Severe soil erosion in the Weihe River basin has attracted much attention due to its impact on land degradation,river bed siltation and sedimentation in reservoirs. Investigations on variations of sediment load and its response to climate change and human activities may provide good reference for river basin management. [Methods] The present study applied the Mann-Kendell nonparametric test,double cumulative curve method and Kriging interpolation to analyze the dynamic variations of rainfall erosivity and sediment load by using daily precipitation data from 23 climate stations and annual sediment load time series at 3 hydrological stations in Weihe River basin from 1961 to 2015.[Results]1) Average annual rainfall erosivity was 1 685. 67 MJ·mm/( hm~2·h·a) in the past 55 years in Weihe River basin. The annual rainfall erosivity showed an insignificant increasing trend of 1. 94 MJ·mm/( hm~2·h·a). The lowest value was 1 507. 23 MJ·mm/( hm~2·h·a),occurring in 1990 s,which was 10%lower than the annual average. In the 1960 s,the rainfall erosivity was 1 685. 67 MJ·mm/( hm~2·h·a),which was similar to the average rainfall erosivity in the last 55 years. The average rainfall erosivity in the1970 s was slightly lower than the average. In the 1980 s and the first 15 years of the 21 st century,the average annual rainfall erosivity was almost the same. 2) The rainfall erosivity ranged from 292. 9 to 4 098. 9 MJ·mm/( hm~2·h·a) in the Weihe River basin with high spatial heterogeneity. The average annual rainfall erosivity in the basin decreased from southeast to northwest. High values occurred in Huashan and Foping station,which were 2 980 and 4 098. 9 MJ·mm/( hm~2·h·a). 3) Sediment load exhibited significant decrease during the past 55 years in the Weihe River basin. Human activities had a greater impact on sediment load at Zhangjiashan and Xianyang stations after 1990 s and the contribution was higher than 100%,which resulted from increasing rainfall erosivity,as well as the vegetation restoration and soil and water conservation. From 1980 to 1994,human activities accounted for 58% of sediment load reduction at Zhuangtou station, and increased up to 67% during 2000—2015.[Conclusions]This study investigated the spatial and temporal changes in rainfall erosivity and sediment load,as well the causes of variation in sediment load in the study area. The results may provide scientific bases for the future soil and water conservation in the Weihe River basin.更多还原