天山东段冰雪消融与产汇流水文过程——以乌鲁木齐河源区为例

应用天山北坡乌鲁木齐河源区1 号冰川、空冰斗和总控3 个水文断面2011 年5-9 月每10min 实测水位数据、15 min 的气温、降水数据、1 号冰川消融及空冰斗区积雪观测数据，采用排除和不排除降水对冰雪消融产流影响的研究方法，系统分析了不同冰川覆盖率下水文断面冰雪消融特征及产汇流过程。结果表明：（1） 乌鲁木齐河源区3 个水文断面流量昼夜差异明显，1 号冰川水文断面白天径流大于夜晚径流，空冰斗和总控断面则相反；3 个断面流量亦具有显著日变化过程，且流量峰值大小和到来的时间存在差异。（2） 在排除与不排除降水两种天气影响下，1 号冰川最大流量滞后最高气温分别为1~3 h 和0~1 h；空冰斗断面分别为10~16 h和13 h，总控断面分别为5~11 h 和6~7 h，反映了1 号冰川从消融产流到汇流时间最短，空冰斗积雪消融产流时间最长，总控位于二者之间，同时亦反映伴随降水过程冰雪融水汇流迅速，即从产流到汇流时间有一定的缩短。（3） 影响3 个水文断面流量变化的因素不同，冰川区热量条件是影响1 号冰川水文断面的关键，1 号冰川在过去20 余年间，冰内、冰下排水道变得更为单一，对融水的阻滞和贮存作用弱化，融水汇流过程变得更为迅速。（4） 冰川覆盖山区流域水文断面在冰川消融期的流量过程线变化及最大流量与最高气温时滞变化规律在一定程度上对于认识冰川覆盖率有差异背景下的流域下垫面水系演化、冰雪消融过程及水文断面径流补给具有重要的指示意义。

Hydrological process of glacier and snow melting and runoff in Urumqi River source region,eastern Tianshan Mountains,China

In this study, the hydrological processes were used to analyze the differences between the glacierized catchment and the non-glacierized catchment of the eastern Tianshan Mountains in the melting season (May-September) in 2011, from two perspectives in regard to and regardless of the influence of precipitation on discharge. The data included the observed hydrological data (10 minutes interval), meteorological data (15 minutes interval), glacier melting and snow observation materials from Urumqi Glacier No.1, Empty Cirque and Zongkong gauging sites in the Urumqi River source region. The results showed that there was difference in the discharge among three gauging sites. The daily discharge was more than the night value at Glacier No.1 gauging site, but it was on the contrary at Zongkong and Empty Cirque gauging sites. Moreover, the discharge at three gauging sites presented an obvious daily variation process, and their peak time points were different. With no consideration of precipitation, the delay time between the maximum discharge and the highest temperature was 1-3 h, 10-16 h and 5-11 h at Glacier No.1, Empty Cirque and Zongkong gauging sites, respectively. If the precipitation was taken into account, the corresponding delay time at three gauging sites was 0-1 h, 13 h and 6-7 h, respectively. The comparison proved that the duration from the discharge generation to confluence was the shortest in the glacierized catchment and the hydrological process became shorter along with the increase of precipitation. Factors influencing discharge change of three gauging sites were different. For Glacier No.1 station, the discharge change was mainly influenced by heat conditions in the glacierized region and the discharge showed an accelerated growth, when the temperature in the melting season was more than 5oC. In comparison, it was found that the englacial and subglacial drainage channel of Glacier No.1 became simpler during the past 20 years. Its weaker retardant and storage on the glacier melting water resulted in the quick discharge confluence. The result also demonstrated the discharge curve and the lag time between the maximum discharge and the highest temperature could reveal the drainage system evolution and the process of glacier and snow melting in different glacier coverage to some extent.