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资源科学 2012
Relationship between Streamflow in Summer at the Headwaters of Urumqi River in the Tianshan Mountains and the 0℃ Isotherm Height
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Abstract:
Urumqi River originates in northern slope of the Tianger Range of Tianshan Mountains. Many previous studies pay more attention to the river runoff of Urumqi River rather than the impacts of the change of 0 ℃ isotherm height in summer on runoff. Therefore, based on the observed materials of daily 0 ℃ isotherm height in summer from meteorological stations and the average daily streamflow materials during 1985-2006 from three hydrological observation stations in the headwater of Urumqi River, the paper has analyzed the 0 ℃ isotherm height change and average daily runoff variety trend and its correlation with statistical methods. The results show that: 1) Streamflow of Glacier No.1 hydrological observation station, Ice-free Cirque hydrological observation station and Master Control hydrological observation station kept increasing during 1985-2006, and the trend rates of them are 0.007m 3 /(s · a), 0.005m 3 /(s · a) and 0.011m 3 /(s · a) respectively. At the same time, the average height of 0 ℃ isotherm increased by 7.917m/a. Besides, the average daily streamflow presents different change trends at the three stations; 2) The correlation between 0 ℃ isotherm height and average daily streamflow at Glacier No.1 hydrological observation station is the best, but the change of the latter is lagging behind that of the former; Master Control hydrological observation station and Ice-free Cirque hydrological observation station respectively have the second and the worst correlation; 3) The correlation coefficient between the average daily streamflow and 0 ℃ isotherm height accumulated value under the condition of 2~3 days ahead and 3~4 days’continuing is the largest; 4) The best regression models are gained by using the time series of the 0 ℃ isotherm height and the average daily streamflow of the Urumqi River, and they present a relation of exponent function.