近50年黄河上游降水变化及其对径流的影响

Precipitation Variations Happened in the Upper Stream of the Yellow River and Effects to Its Runoff in the Last 50 years

利用黄河上游兰州以上地区降水量资料,在统计分析近50年降水时空分布和变化基本特征,以及各站降水量与兰州站天然年径流量关系的基础上,选取代表站,计算区域平均降水量,并建立天然年径流量计算公式,计算分析了降水变化对径流量的影响。结果表明,20世纪70、80年代降水变化对天然年径流量的影响不甚明显,而90年代以来影响十分显著,其影响幅度达10%～20%。

The paper selects typical stations, calculates the average regional precipitation, establishes a calculation formula of natural annual runoff and calculates and analyzes the effect of precipitation variation to the runoff by utilizing the precipitation data of the region above Lanzhou, upper stream of the Yellow River and based on the basic features of temporal and spatial distribution of precipitation in the last 50 years and the relationship between precipitation of each station and natural annual runoff volume of Lanzhou Station. The results shown that the effect of precipitation variations in 1970s and 1980s to the natural annual runoff volume is not clear, while it becomes greatly notable since 1990s and the effected range reaches to 10%～20%.