天山乌鲁木齐河上游径流极值变化分析研究

以天山乌鲁木齐河上游作为研究对象, 结合乌鲁木齐河上游近50 a的实测月均径流变化资料, 对未来的月均径流进行了预测. 基于对重现水平的95%置信区间进行估计的结果表明, 乌鲁木齐河上游重现期为10 a、25 a、50 a和100 a的月均径流量极大值分别约为35.4 m³·s^-1、39.9 m³·s^-1、43.2 m³·s^-1和46.3 m³·s^-1;重现期为10 a、25 a、50 a和100 a的月均径流量极小值分别约为0.60 m³·s^-1、0.43 m³·s^-1、0.30 m³·s^-1和0.18 m³·s^-1. 在当前气候变化背景下, 乌鲁木齐河上游在2058年前后枯水期时可能发生断流现象. 该研究对乌鲁木齐河径流变化预测具有重要意义.

A Study of the Variation of Extreme Runoff in the Upstream of the Ürümqi River,Tianshan Mountains

Extreme value theory is the major means to deal with extreme events of small probability, which has been widely used in hydrology. In this paper, based on the theory and method of generalized Pareto distribution model, the extreme runoff in the upstream of the Ürümqi River, Tianshan Mountains was predicated. The results of different average runoff return levels, which contain 95% confidence intervals, indicate that the maximum average monthly runoff corresponding to 10 a, 25 a, 50 a and 100 a return period is 35.4 m³·s^-1, 39.9 m³·s^-1, 43.2 m³·s^-1 and 46.3 m³·s^-1, respectively, and the minimum average monthly runoff corresponding to 10 a, 25 a, 50 a and 100 a return period is 0.60 m³·s^-1, 0.43 m³·s^-1, 0.30 m³·s^-1 and 0.18 m³·s^-1, respectively, in the upstream of the Ürümqi River. Regarding the impact of present climate change, it is expected that the upstream of the river will dry up in the dry season around 2058. The results are only from the statistically significant associations. Of course, there are substantial uncertainties about the extreme runoff prediction.