气候变化和人类活动对玛纳斯河流域径流及干旱的影响

Impact of Climate Change and Human Activities on Runoff and Drought in Manas River Basin

基于1956—2020年玛纳斯河流域逐月降水和径流资料,运用Mann-Kendall非参数检验法、双累积曲线法和标准化径流指数(standardized runoff index,SRI)揭示了流域径流量的年际变化趋势,定量描述了气候变化和人类活动对流域径流变化的贡献比例,同时探究了气候变化和人类活动影响下流域季节尺度的干旱变化特征。结果表明:①玛纳斯河流域年径流量呈上升趋势,并在1995年发生了显著性突变;②气候变化是导致玛纳斯河流域径流量增加的主要因素,气候变化和人类活动对流域径流量增加的贡献率分别为56.73%、43.37%;③从季节尺度上看,相较于受气候变化的影响,人类活动降低了流域干旱事件发生的频率,改善了流域冬季的干旱状况,但同时春季农田灌溉需要消耗大量的水资源,使得流域春季呈现出干旱化趋势。

On the basis of the monthly precipitation and runoff data of Manas River Basin from 1956 to 2020,the Mann-Kendall nonparametric test method,double cumulative curve method,and standardized runoff index(SRI)are adopted to reveal the interannual variation trend of watershed runoff and quantitatively describe the contribution proportion of climate change and human activities to watershed runoff change.In addition,the characteristics of seasonal drought change are explored under the influence of climate change and human activities.The results indicate that:①the annual runoff of Manas River Basin shows an upward trend,and a significant mutation occurred in 1995;②Climate change is the main factor leading to the increase in runoff in Manas River Basin,and the contribution rates of climate change and human activities to the increase in runoff are 56.73%and 43.37%,respectively;③On a seasonal scale,in contrast with the impact of climate change,human activities reduce the frequency of drought events in the basin and improve the drought situation in winter.In the meanwhile,however,farmland irrigation in spring consumes enormous water resources,which results in the trend of drought in the basin in spring.