1960-2012年河西内陆河上游山区降水量变化及其区域性差异分析

基于我国河西内陆河流域有关水文、气象台站的观测数据，对1960年代以来河西走廊的石羊河、黑河、疏勒河三大内陆河水系上游山区降水变化特征、趋势及区域时空变化差异进行了分析.结果表明：受全球变暖的影响，石羊河、黑河、疏勒河流域上游的降水量年代际、年际及季节性的变化总体上呈增加的态势，但不同区域降水增幅存在着一定的差异.其中，1960年代，位于祁连山东部的石羊河水系上游山区、中部的黑河水系上游山区及西部的疏勒河水系上游山区普遍少雨；1970年代，石羊河山区降水偏多并持续至今，黑河、疏勒河水系上游山区则降水偏少；1980年代，三大水系上游山区均多雨；1990年代的黑河、疏勒河山区和2000年代的三大水系上游山区均多雨；2010年以来，黑河山区降水偏少，石羊河与疏勒河山区降水均偏多.相对而言，位于祁连山西部山区的疏勒河水系上游年降水量与夏季降水量的增长较为显著.

Changes of Precipitation in Mountainous Areas of the Three Large Inland River Basins in the Hexi Corridor and Their Regional Differences During 1960-2012

All rivers in the Hexi Corridor of Gansu Province originate from the north slopes of the Qilian Mountains and respectively belong to three large river systems, which are the Shiyang River, the Heihe River and the Shule River from east to west. The rivers are supplied by precipitation and snow and ice meltwater from the Qilian Mounta-ins. Therefore, the changes in precipitation and temperature in the upriver watershed of the rivers have quite pronounced effect on the change in mountain runoff and reasonable utilization of water resources in the Hexi Corridor. For this reason, the Qilian Mountains, together with the upstream watershed and runoff forming areas, are chosen as a study area, where the change characteristics and variation trend of precipitation under global warming backdrop are analyzed based on the observed data in the area. The results show that precipitations in the upper reaches of Heihe River and Shule River located in the middle and western Qilian Mountains have increased, but the annual and seasonal precipitations decreased in the 1960s, which means, as a whole, the climate in the upper reaches of the three river systems has shifted to wet in the past about 60 years.