中文摘要：

依据长江源区1956~2012年水文、气象数据,采用距平分析、集中度、集中期、不均匀系数等方法,分析了该地区近年降水、径流、泥沙变化趋势及其原因。结果显示：2005~2012年期间,长江源区降水量、降雨日数增加,降雨强度亦增强,降水集中度、不均匀系数略有减小;源区径流量明显增加,径流集中度、不均匀系数明显减小,集中期有所推后,枯季径流占全年径流的比例明显提高;河流泥沙年内趋于均匀,含沙量、输沙量呈明显减小趋势。上述径流变化以及下垫面生态植被覆盖条件好转是泥沙变化的主要原因。研究成果为长江源区流域规划和生态保护提供了有益参考。

英文摘要：

On the basis of the hydrological and meteorological data in the source region of Yangtze River from 1956 to 2012, the distance average analysis, concentration degree, concentration period, non - uniform coefficient method are adopted to analyze the variation trends of precipitation, runoff, sediment in recent years and the variation causes are studied as well. The results show that from 2005 to 2012, the precipitation, rainy days and the rainfall intensity increases; the precipitation concentration de- gree and the non - uniform coefficient decreases slightly; the runoff increases obviously, and the runoff concentration degree and non - uniform coefficient decreases; the concentration period is delayed, the proportion of dry season runoff in the annual runoff increases. The sediment tends to be uniform within a year, the sediment concentration and discharge shows a significant decreasing trend. The causes for the sediment variation include the above - mentioned variation of runoff and the improvement of vegetation cover conditions.