中文摘要：

随着全球或区域气候的变化,加上渐强的人类活动的影响,世界上一些河流的径流量发生了明显减小的变化趋势,这在干旱及半干旱地区的河流中尤其明显。在我国,北方干旱及半干旱地区河流的径流量的减小已经引起了严峻的生活及生态方面的问题。因此查明流域径流量的变化特征、趋势及分析其原因,是流域管理中面临的重要科学问题。该研究以黄河中游一级支流皇甫川流域为例,利用1960-2008年的数据资料,采用累积距平方法、年际累积量方法,分析了该流域径流量和降水量的变化趋势,识别出径流量变化过程中1979和1998为其两个突变年份,而降水量变化过程中仅存在唯一的突变年份1979。利用统计分析法分别分析了1960-1979、1980-1997和1998-2008三个时期的累积径流量与年份之间的线性关系,以及1960-1979、1980-2008两个时期累积降水量与年份之间的线性关系。采用本文提出的新的计算方法——累积量斜率变化率比较方法,以1960-1979为基准期,在不考虑蒸散总量的影响时,计算得出皇甫川流域径流量减小的降水量和人类活动的相对贡献率在1980-1997年间分别为36.43%和63.57%,在1998-2008年间分别为16.81%和83.19%。该研究结果揭示了皇甫川流域近半个世纪以来径流量的变化趋势及其主要影响因素的贡献率,对于该流域未来水资源的开发利用具有重要指导作用。同时,所提出的定量研究方法可以应用在干旱—半干旱地区河流径流量变化及其影响因素的定量评估中。

英文摘要：

The runoff of some rivers in the world especially in the arid and semi-arid regions has decreased remarkably with global or regional climate change and intensive human activities.The runoff decrease in the arid and semi-arid areas of northern China has brought severe problems in livelihood and ecology.So,to reveal the changing characteristics,trends of runoff and their influencing factors have been an important scientific problem for drainage basin management.This study,taking the Huangfuchuan drainage basin as an example,analyzes the changing trends of the runoff and precipitation according to the measured data in 1960-2008.Two inflection points,1979 and 1998,for the accumulative runoff,and one inflection point,1979,for the accumulative precipitation,were identified according to the methods of accumulative anomaly analysis.The linear relationships between year and accumulative runoff in 1960-1979,1980-1997 and 1998-2008 and between year and accumulative precipitation in 1960-1979 and 1980-2008 were fitted.Adopting the new method put forward in this study,we made a comparison of slope change ratio of the fitted beeline between year and accumulative quantity,and taking 1960-1979 as the base period,we obtained the contribution rates of the precipitation and human activities to the decreased runoff,which were 36.43% and 63.57% in 1980-1997,and 16.81% and 83.19% in 1998-2008,respectively.This study revealed the changing trend of runoff of the Huangfuchuan drainage basin during 1960-2008 and calculated the contribution ratio of the main influencing factors.It plays an important role in the drainage basin management in arid and semi-arid areas.Contemporarily,the new method of quantitative research can be applied in the quantitative evaluation of runoff change in the river basin of arid and semi-arid areas.