Characteristics of runoff variation during ablation season in Laohugou watershed of western Qilian Mountains

Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》

晋子振 秦 翔 赵求东 李延召 刘宇硕 陈记祖 王利辉 王 强

Abstract： Based on the runoff data and meteorological data of Laohugou watershed in the western of Qilian Mountains, northwest China, the research analyzed the relationship between runoff and meteorological variables in glacier area, and established a multivariate exponential nonlinear regression to reconstructe the runoff. In addition, the characteristics of interannual, seasonal, diurnal variations of runoff in the glacial region were analyzed. The results showed that: (1) The correlation between runoff and temperature is the highest (0.86), followed by water vapor pressure (0.81), relative humidity (0.46), and precipitation (0.27). Runoff is most affected by temperature. (2) The mean daily runoff is 2.10 m3 ·s -1 in this century, which is higher than 1.65 m3 ·s -1 in the late 1950s, the main reason is that the temperature increased by 0.75 ℃ in the ablation season. The interannual variation of runoff is large in the strong ablation period, and the interannual variation is small in the beginning (May-June) and end (September) of the ablation period. The proportion of runoff generation from May to September was 5.3%, 16.1%, 37.3%, 35.1% and 6.2%, respectively. (3) Multivariate exponential nonlinear regression equation can better simulate the daily runoff (the mean Nash efficiency coefficient is 0.70). After the supplement of the missing runoff, the diurnal variation of runoff is small in the beginning and end of the ablation period, but the diurnal variation of runoff is large in the strong ablation period. For the time-lag effect of runoff, monthly runoff in Laohugou watershed showed a characteristic of diurnal variation of“valley-peak”during the ablation period. The time interval between the maximum temperature and the maximum runoff was long in the beginning and end of the ablation period, while the time interval was short between the maximum temperature and the maximum runoff during the strong ablation period, and the maximum difference between the maximum temperature and the maximum runoff was 3 hours in June.

 Hits 6274  Downloads 279  Comment