天山乌鲁木齐河源1号冰川昼、夜径流变化特征

Characteristics of Daily Cycle of Discharge from Glacier No.1 at Headwaters of rümqi River

利用天山乌鲁木齐河源1号冰川2001-2005年消融期的水文气象实测资料,分析了河源区径流量的昼、夜变化特征,并对径流变化过程与气温、降水等关系进行了相关分析.结果表明:从5月份消融初期开始,昼、夜平均流量都较小,随着强消融期的到来,迅速增大,到消融期后期(8月份末),又逐渐变小.就年际相同月份昼(夜)平均流量相比而言,不确定性较大;年内消融季节各月昼、夜平均径流的变化不同:5月份基本没有昼夜变化,从6月份昼夜变化增大,而且径流最大值出现在16:00-18:00,最小径流发生在9:00-10:00.消融季节各月典型晴朗天气下的径流延迟情况是:6月份最大径流比最高气温延迟1～2h,7月基本没有延迟,8月份延迟2～3h;6-8月份的昼、夜平均径流量比率都大于1(除2002年6月),从6月份开始比率逐渐增大(除2004年7月).

Characteristics of the daily cycle of discharge and the relation between discharge and the extreme air temperature are analyzed based on the observation during 2001-2005 in the Glacier No.1 at the headwaters of the rümqi River,Tianshan Mountains.The studies indicate that the daytime and nighttime discharges were small at the preliminary ablation stage in May,and then became more.The daytime（or nighttime） discharge in the same month for different years was different.The daily cycle of discharge for different months during su mmer months were dissimilar.It did not change much in May and then increased from June.The maximum runoff was observed in the evening（16：00-18：00） and the minimum one occurred in the morning（9：00-10：00）.Meltwater runoff usually had lags behind air temperature for the selected clear days.In June the peak runoff delayed one to two hours comparing with the daily maximum air temperature,while it hardly delayed in July.However,it delayed about two to three hours in August.The ratios of monthly daytime discharge to nighttime discharge in su mmer months during 2001-2004 were larger than 1.0,except for July,2002.The ratio increased from May to August,except for 2004.