策勒河出山径流特征及其趋势

Changing trend and features of the runoff from mountain areas of the Qira River

根据策勒河近50年水文及气象资料,利用经验频率、Mann-Kendall非参数检验和非线性回归分析等方法,分析策勒河径流量的变化特征、变化趋势及其对气候的响应。结果表明:策勒河径流年内分配不均,夏、秋季偏丰,5～9月径流量占全年88.70%;冬、春季偏枯,10月到次年4月径流量占全年11.30%,策勒河变差系数为0.21,径流最大值与最小值之比为2.53,河流年际变化相对稳定;Mann-Kendall检验得出近十年出山径流量有减少的趋势;月平均流量与月平均降水量、月平均蒸发量和月平均气温之间存在复杂的非线性关系,非线性回归模型模拟的月平均流量与实测值对比,确定系数为0.73,模拟效果较好,月平均蒸发量与月平均流量呈负相关。

Water is one of main control factors of the sustainable development in the oasis region, understanding the characteristics of runoff changes of the Qira River is useful to plan and use water resources rationally and promote the oasis sustainable development of society and economy. According to nearly 50-year hydro-meteorological data of the Qira River, in virtue of the frequency of experience, Mann - Kendall non-parametric test methods, the characteristics of runoff interannual variation of the Qira River and its changing trend were analyzed. The results show that： the distribution of runoff is uneven in a year, summer and autumn with much more runoff, namely, the runoff from May to September accounted for 88.7% ; winter and spring is with less runoff, the runoff from October to next April accounted for 11.3%. The Qira River value is 0.21 and maximum ratio 2.53. The interannual variation of runoff is relatively stable. Mann - Kendall test indecates a decrease trend of runoff in the past decade. There are complex nonlinear relationships between the monthly average runoff and average precipitation, the average evaporation and average temperature. The average monthly runoff determined with nonlinear regression model was compared with its measured one, whose NSE value is 0. 729 7, and the simulation results are better. The average evaporation is negatively correlated with the average runoff, which results in monthly runoff reducing, the temperature and evaporation increasing.