1959—2008年乌鲁木齐河源1号冰川融水径流变化及其原因

Analysis on Runoff Variation of Glacier No.1 at the Headwaters of the Urumqi River from 1959 to 2008

采用数理统计、Morlet小波分析和Mann-Kendall突变检验对乌鲁木齐河源1号冰川1959—2008年径流序列进行分析,揭示了冰川融水径流的变化趋势、周期特征和突变特性,并对径流与气候、冰川变化关系进行了探讨。结果表明:乌鲁木齐河源1号冰川近50 a来径流增加趋势显著,特别是在1993年发生突变后,平均径流较1993年前增加了69.4%。径流序列第一主周期为15 a,第二主周期为6 a。在13～16 a时间尺度上看,1号冰川融水径流在未来的几年将继续保持偏多趋势,但是从5～7 a和超长期时间尺度上看则相反。冰川融水径流与冰川物质平衡、年均气温、消融期气温及年降水量存在良好的瞬时响应关系,其中消融期气温的振动对冰川融水径流振动能量贡献最大,在气温超过2℃时,径流将加速增长。物质平衡变化100mm可引起河流径流变化22.9×104m3,1号冰川过去50 a累积物质平衡为-13 693 mm,相当于额外补给河流径流量3 135.7×104m3,约是年径流量的16.1倍。

Based on multiple methods,such as mathematical statistics,Morlet wavelet analysis and Mann-Kendall method,runoff variation of Glacier No.1 at the headwaters of the Urumqi River during 1959-2008 was analyzed in order to detect its changing trend,periodicity characteristics and mutation features.Then the relationships among runoff,climate and glacier change were also discussed.The results firstly showed that runoff of Urumqi Glacier No.1 experienced an increasing trend in recent 50 years;especially since 1993 the increase was more obvious.Secondly,the first principal periodicity of runoff series was 15 years and the secondary one was 6 years.From 13-16 years scale,the glacier runoff would continue to increase in the future years.However,an opposite tendency existed from another time scales of 5-7 years or more.Thirdly,there was a good instantaneous response relation among glacier runoff,glacier mass balance,annual average temperature,temperature in the melt season and annual precipitation.More specifically,the vibration of temperature in the ablation season gave the greatest contribution to glacier runoff vibration,and glacier runoff showed an accelerated growth when the temperature was more than 2 ℃.It was finally concluded that 100 mm change of glacier mass balance could cause 22.9×104 m3 river runoff.The cumulative mass balance of Glacier No.1 reached up to-13693 mm in the past 50 years,which was equivalent to 3135.7×104 m3 additional supplies of river runoff and was about 1.6 times that of the river annual runoff.This study highlighted the relationships between climate-induced glacier change and runoff yield.The mutation and periodicity of glacier mass balance was also analyzed,so the inherent law of glacier runoff was revealed to some extent.