气候变化和人类活动对湟水河流域径流量影响的定量评估

湟水河是西北干旱区重要河流之一,对维持西北干旱区生态平衡具有极其重要的作用。近年来,湟水河流域水资源减少已经引起了严重的生态环境问题,本文根据流域内1966-2010年水文气象数据,采用累积距平法、累积量斜率变化率法,对湟水河流域径流量和气候变化特征及趋势进行了分析,并定量评估了气候变化和人类活动对径流量变化的影响。结果表明:年降水量、蒸散发量和径流量总体均呈减少趋势;径流量的下降变幅为0.1亿m3/10a,具有4a、9a和20a的准周期变化,且在1987年前后发生了突变;气候变化对湟水河流域径流减少的贡献率达35.46%,人类活动改变了部分水循环的路径,对径流的减少起主导作用,贡献率为64.54%。

The Impact of Climate Variability and Human Activity on Runoff Changes in the Huangshui River Basin

The Huangshui River is located in a semiarid area of northwestern China and plays a significant role in maintaining water balance and ecological health of NCP. Since the beginning of the 21st century,frequent extreme weather events have resulted in significant changes under a background of global climate change. In the past few decades,decreasing runoff in the Huangshui River Basin associated with climate variability and human activities has caused a series of water and eco-environmental problems. These have had a profound and lasting impact on the hydrologic progress. Assessing and separating the responses of runoff to these two driving factors is urgent. Based on meteorological and hydrological data from 1966-2010 and using accumulative anomaly, nonparametric Mann-Kendall test,and the change rate of accumulation slope,we analyzed runoff and climate in this region and calculated the contribution rates of climate change and human activity. The results show that annual precipitation,evaporation and runoff are decreasing. Annual runoff decreased by 0.1 hundred million m³/10a,there are periods of 4a,9a,20a and an abrupt change was identified around 1987. Climate variation accounted for 35.46% of the decrease in runoff,while human activities altered the cycle route of water in the basin,accounting for 64.54%. Human activities are a dominant influence in the decline in runoff across the Huagshui River Basin.