祁连山区气候变化对黑河出山径流的影响

Impacts of Climate Change in Qilian Mountain Area on Runoff in the Heihe River Basin

以黑河上游流域为研究区,依据祁连山区4个气象站的逐月实测气象资料及莺落峡水文站逐月径流资料,采用Penman-Monteith方法计算了潜在蒸散发量,采用线性回归以及Mann-Kendall趋势检验等方法研究了降水、潜在蒸散发、气温及径流的年、季变化趋势,运用弹性系数法分析了降水、气温和潜在蒸散发变化对黑河出山径流的影响。结果表明:(1)黑河流域气候水文要素的总体年际变化为年降水量和气温均呈显著升高趋势,潜在蒸散发量呈不显著增加趋势,出山口莺落峡水文站径流量呈显著增大趋势;(2)祁连山区降水量、气温和潜在蒸散发量是影响黑河流域出山径流量的主要气象因子,径流与降水在年和季节尺度上都存在显著相关关系,其中祁连山区秋季降水量与莺落峡站径流量的相关性最为显著,春季气温与径流量呈正相关,气温升高促进了冰雪消融,进而增大径流量,潜在蒸散发量特别是夏季蒸散发量增大对降水量增大造成的年径流增大起到了一定的削弱作用;(3)祁连山区降水量增加1%将使莺落峡站径流量增加约0.74%,祁连山区气温升高1%将使莺落峡站径流量增大约0.16%,祁连山区潜在蒸散发量增加1%将导致莺落峡站径流量减少约1.75%。

The upperHeihe River basin in Gansu Province was taken as the research area in this paper. Based on the monthly observed meteorological data from four meteorological stations of the Qilian Mountain area and monthly observed runoff data from Yingluoxia Hydrologic Station of Heihe River basin,the Penman-Monteith formula was used to calculate the potential evaporationET_0,meanwhile the Linear regression and Mann-Kendall trend test methods were used to research the annual and seasonal variation of precipitation,atmospheric temperature, ET_0 and runoff. What was more,the elastic coefficient method was used to study the effect of the climate changes on rainfall. The results show that a)the increasing trend of annual precipitation and atmospheric temperature,the overall annual variation of hydrology and climate factors is obvious in Heihe River basin. The rising tendency of potential evaporation is not significant. The increasing trend of runoff is prominent in Yingluoxia Hydrometric Station;b)precipitation,atmospheric temperature andET_0 in Qilian Mountain are the main meteorological factors that affect the runoff at Yingluoxia Station in Heihe River basin. Runoff and precipitation are observably correlated in annual and seasonal scales and the relationship between precipitation of Qilian Mountain area in autumn season and runoff at Yingluoxia Station is the most conspicuous. The atmospheric temperature in spring is positively correlated with runoff. The temperature rising promotes the snow melt of Qilian Mountain,which further produces runoff. The potential evaporation,especially in summer,has a certain effect to weaken the increase of flow caused by rainfall increasing;c)1% rise of precipitation on Qilian Mountain will cause runoff to increase by 0.74% at Yingluoxia Station,1% growth of atmospheric temperature on Qilian Mountain will result in runoff increasing by 0.16% at Yingluoxia Station and 1% increase of potential evaporation on Qilian Mountain will lead to runoff decreasing by 1.75% at Yingluoxia Station.