中文摘要：

根据黑河流域取得的降水水样和降水气象资料，分析了该区域降水中氢氧同位素的时空差异与水汽输送的关系，定量估算了大陆性局地水汽循环在总降水中所占的比率。研究表明，春夏季降水主要受海洋性水汽来源影响，秋冬季降水受大陆性局地水汽来源影响；受水库水体蒸发水汽影响的附近区域降水氘盈余偏高，受海洋蒸发水汽控制的祁连山区降水氘盈余接近全球平均值10‰；基于氘盈余值估算，局地水循环对区域降水贡献率较大，占全年降水比例至少达31．06％。

英文摘要：

The Heihe River, as one of the greatest inland rivers in China, was confronted with water resources＂ scarceness due to unreasonable development or utilization. To utilize effectively the limited water resource, isotope techniques was widely used to study water cycle. Precipitation from different water vapor sources was analyzed by using isotope tracers based on some precipitation sampling sites in the Heihe River basin. Based on the analysis of the linear slope of δD - δ^l8O associated with deuteriuna excess, conclusions were drawn that water vapor for precipi- tation in spring and summer mainly come from the ocean air mass, and conversely the precipitation in autumn and winter is mostly formed of continental recycling water. The trajectory of water vapor for one large - scale precipitation in July is from the mountain area to the basin in front of the mountain because of the decline of tritium content in precipitation. Deuterium excess ranges from -45%0 to 65%0 with large scope, which means the complicated water vapor and the complex conditions of precipitation. Deuterium excess is some higher than 10‰ in precipitation at stations near reservoir due to a key role of its evaporation water in water cycle, and that almost equals to 10‰ of the worldwide mean in precipitation of the mountain areas with water vapor controlled by ocean air mass. With the deuterium excess evaluated for water vapor sources, the proportion of precipitation formed by the continental recycling water evaporation was estimated at least 31.06% in total preeipitation.