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利用长江上游主要水文站1956~2010年输沙量数据和雨量站日降雨量时间序列资料,采用线性回归研究流域降雨侵蚀力与河流输沙量的关系,并估算长江上游各子流域降雨侵蚀力变化对河流输沙量的总体贡献。结果表明:长江上游降雨侵蚀力为2 362 MJ·mm/(hm2·h·a)到3 814 MJ·mm/(hm2·h·a),多年平均值为3 006MJ·mm/(hm2·h·a);各子流域的年均降雨侵蚀力差异较大,其中乌江子流域最大,为5 055 MJ·mm/(hm2·h·a),金沙江子流域最小(1 560 MJ·mm/(hm2·h·a)),不足乌江子流域的1/3。各子流域降雨侵蚀力的极值比大小嘉陵江>岷江>乌江>金沙江。长江上游流域以及子流域输沙量在1956~2010年间均呈总体下降趋势,各子流域年均输沙量大小金沙江>嘉陵江>岷江>乌江。降雨侵蚀力变化对长江上游输沙量变化贡献率为7%,对岷江、嘉陵江、乌江子流域输沙量变化的贡献率分别为36%、20%、9%。总体来说,降雨对长江上游输沙量变化的影响不如人类活动的影响大。
Based on the time series data of sediment discharge and rainfall daily rainfall of the main hydrological stations in the upper reaches of the Yangtze River from 1956 to 2010, the relationship between the rainfall erosivity and the sediment discharge was studied by linear regression. The rainfall erosivity of each sub-catchment in the upper reaches of the Yangtze River Changes in the overall contribution of river sediment load. The results show that the rainfall erosivity in the upper reaches of the Yangtze River reaches from 2 362 MJ · mm / (hm2 · h · a) to 3 814 MJ · mm / (hm2 · h · a), and the annual average is 3 006 MJ · mm / (hm2 · h · A). The average annual rainfall erosivity of each sub-basin is quite different, among which the Wujiangzi basin is the largest, which is 5 055 MJ · mm / (hm2 · h · a) and the Jinshajiang subbasin is the smallest (1 560 MJ · mm / ( hm2 · h · a), less than 1/3 of the Wujiang River basin. The extreme value of rainfall erosivity of each sub-basin is smaller than that of Jialing River, Minjiang River, Wujiang River and Jinsha River. The volume of sediment transport in the upper reaches of the Yangtze River and its sub-basins all showed an overall downward trend from 1956 to 2010, and the average annual sediment discharge in the sub-basins was Jinsha River> Jialing River> Minjiang River> Wujiang River. Changes in rainfall erosivity contributed 7% to the change of sediment load in the upper reaches of the Yangtze River, contributing 36%, 20% and 9% of the sediment load changes in the Minjiang River, Jialing River and Wujiangzi respectively. In general, the impact of rainfall on the sediment transport in the upper reaches of the Yangtze River is less affected than that of human activities.