黑河流域上游融雪径流时间变化特征及成因分析

Analyses on Temporal Variations of Snowmelt Runoff Time in the Upper Reaches of Heihe River and Its Climate Causes

以黑河流域上游莺落峡水文站和札马什克水文站1959-2008年及祁连水文站1967-2008年的天然径流序列为基础数据,通过计算水文站的流量质心时间来表示融雪径流时间,研究了黑河流域上游融雪径流时间变化的特征.结果表明:莺落峡站和札马什克站自20世纪70年代起,融雪径流时间表现为提前的趋势,祁连站自20世纪80年代起融雪径流时间提前.野牛沟站和祁连站10月至次年4月降水量增加或4-7月气温升高,会使得莺落峡站融雪径流时间提前,札马什克站融雪径流时间的提前与野牛沟站10月至次年4月降水量的增加具有较高的相关性,祁连站融雪径流的提前与祁连气象站4-7月气温升高的相关性较强.通过分析莺落峡站融雪径流时间与年径流及各季节径流的相关性,可知如果融雪径流时间提前,莺落峡站观测到的年径流量和夏秋季的径流量均会减少,而同时冬春季的径流量会增加,这对合理安排流域水资源配置和管理具有重要的指导意义.

Spring snowmelt is the most important contribution to water resources of Heihe River in Northwest China.Timing of the Center of Mass for Flow（CT） was used as a proxy of timing of snowmelt runoff in this study,which was investigated in Yingluoxia and Zhamashike from 1959 to 2008,and in Qianlian（hydrological station） in the upper reaches of Heihe River from 1967 to 2008.The characteristics of the decadal variations of CT show that snowmelt runoff in Yingluoxia and Zhamashike has become ahead of time since the 1970s,and snowmelt runoff in Qianlian also has become earlier since 1980s.Pearson correlation coefficient between snowmelt runoff time（CT） in each station and local temperature index（TI） and precipitation index（PI） were calculated.It is found that the increase of air temperature from April to July or precipitation from October to April in the next year would result in the earlier snowmelt runoff time in Yingluoxia and Zhamashike.The temperature variation of Qianlian from April to July has greater influence on the snowmelt runoff time in Qianlian than precipitation variation in the cold season.Correlation between the timing of snowmelt runoff and the annual runoff in Yingluoxia demonstrates that timing advance of snowmelt runoff may lead to decreases in annual runoff and runoff of summer and autumn,but runoff would increase in spring and winter during the study period.