青海湖流域径流变化趋势及归因分析

Trend and Attribution Analysis of Runoff in Qinghai Lake Basin

针对青海湖流域近年来径流量增加的现状,根据流域内1976~2016年水文、遥感观测数据,采用滑动平均法、Mann-Kendall趋势检验及突变检验法、距平累积法和双累积曲线法研究了流域气温、降水、径流及积雪等的时空特性。结果表明,青海湖流域气温总体变化呈上升趋势,并在1998年前后发生突变;1976~2016年气温上升率为0.06℃/a;流域内降水量呈缓慢上升,2014年后降水量显著增加。布哈河流域近5年冰雪覆盖面积缩小较迅速且入湖径流量上升趋势显著;通过径流影响因素分析,2005~2015年冻土及冰雪融化对径流影响占主导地位,达75%,降水量占25%。这说明青海湖流域正向暖湿化发展,近年来青海湖湖泊的扩张主要是由降水和径流增加所致。

According to the hydrological and remote sensing data of 1976-2016 years in the Qinghai Lake Basin,the temporal and spatial characteristics of watershed temperature,precipitation,runoff and snow cover were studied by moving average method,Mann-Kendall trend test and mutation test,anomaly cumulative method and double cumulative curve method.The results indicate that the temperature of Qinghai Lake Basin changes in the overall upward trend,and mutated in 1998.The temperature rise rate during1976-2016 year is 0.06 C/a.The precipitation in the basin increased slowly,and the precipitation increased significantly after 2014.The ice covered area in Buha River Basin in recent 5 years is shrinking rapidly and runoff flow into the lake rise significantly.Through the analysis of the influencing factors of runoff,the 2005-2015 year permafrost and the melting of ice and snow have a dominant influence on the runoff,accounting for75%,and the amount of precipitation is 25%.The Qinghai Lake Basin is developing to the trend of warm and humid.In recent years,the expansion of Qinghai Lake is mainly caused by the increase of precipitation and runoff.