气候变化对河川径流量的影响--以皇甫川流域为例

Impact from climate change on amount of river runoff——a case of Huangfuchuan Watershed

基于非参数检验方法 Mann-Kendall法,对黄河中游皇甫川流域的降水、平均气温和径流量的长期变化趋势和序列突变情况进行了检验,并运用水文敏感性分析和降水—径流相关关系分析两种方法探究了皇甫川流域径流锐减的原因。1985—2006年,皇甫川流域的气候暖旱化趋势显著。其中,年降水系列呈减少趋势,但减少趋势不显著;年平均气温呈明显的上升趋势,远远超过了α=0.05的显著性水平。年径流量也表现出显著的减少趋势,显著性水平α=0.1。径流突变性检验结果显示,在1998年前后皇甫川径流出现显著变化,天然时期(1985—1998年)和径流变化时期(1999—2006年)相比,年均径流量减少了60%。归因分析表明,气候变化因素对年均径流变化的贡献率为46%,说明气候变化是导致径流减少的重要因素。

Based on the nonparametric Mann-Kendall test method,the long-term changing trends and the change-points of the precipitation,the mean temperature and the amount of runoff of Huangfuchuan Watershed of the Mid-Yellow River are tested,and then the causation of the sharp decrease of the runoff within the watershed is explored with both the methods of hydrological sensitivity analysis and precipitation-runoff correlative relation. From 1985 to 2006,the climate warming and drying trend is significant therein; in which the annual precipitation exhibits a decreasing trend,but it is not so significant,while the mean annual temperature presents a rising trend,which is far over the significance level of α = 0. 05. Meanwhile,the amount of the annual runoff also shows a significant decreasing trend with the significance level of α = 0. 1. The testing result of the runoff change-points shows that significant changes of the runoffs of Huangfuchuan Watershed has occurred before and after 1998,i. e.,compared the natural period（ 1985—1998） with the period of the runoff variation（ 1999—2006）,the amount of the mean annual runoff has decreased by 60%. It is indicated through the relevant attribution analysis that the rate of the contribution from the factor of climate change to the mean annual runoff variation is 46%,which demonstrates that the climate change is an important factor for the decrease of the runoff.