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Arid Land Geography ›› 2020, Vol. 43 ›› Issue (5): 1192-1201.doi: 10.12118/j.issn.1000-6060.2020.05.04

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Climate change and its runoff response in the middle section of the Qilian Mountains in the past 60 years

CHENG Peng1, 2, KONG Xiang-wei3, LUO Han1, LI Bao-zi1, WANG Yan-feng1   

  1. 1 Gansu Weather Modification Office, Lanzhou 730020, Gansu, China; 2 Key Laboratory for Cloud Physics of China Meteorological Administration, Beijing 100081, China; 3 Lanzhou Central Meterological Observatory, Lanzhou 730020, Gansu, China
  • Received:2019-05-29 Revised:2020-01-06 Online:2020-09-25 Published:2020-09-25

Abstract: Based on hydrological and meteorological data from 1960 to 2017, the characteristics of variations in cli? mate and runoff in the middle section of the Qilian Mountains were studied by using correlation characteristics, mu? tation analysis, and wavelet analysis. The results showed thatover the past 60 years, temperature, precipitation, and runoff in the middle section of the Qilian Mountains showgenerallyincreasing trends. The annual average tempera? ture in this region rose at the rate of 0.39°C·(10 a)- 1. The annual minimum temperature rose much higher than the maximum and average temperatures, and temperature increased in all seasons, especially in the winter. The in? crease of precipitation in the middle Qilian Mountains (approximately 19.2% over the past 60 years) was prominent in northwestern China. This increase is mainly due to increased summer precipitation. There was climate warming and a humidifying trend, with winter warming and summer humidification being more obvious. The mutation analy? sis showed that the average temperature changed abruptly in 1993, which occurred earlier than other regions of northwestern China. The main periods of temperature and precipitation were 8 a and 30 a, respectively. In the runoff period response, the short period (8 a) is consistent with average temperature oscillation, whereas the long period (30 a) is consistent with annual average precipitation. Further simulation results confirmed that precipitation and temperature were the main factors affecting runoff. The established runoff prediction model has a Nash efficiency co? efficient of 0.68, thus it can be used for analyzing and predicting runoff. Precipitation and temperature helped in? crease runoff by 21.1% and 10.9%, respectively, and the impact of precipitation on runoff is greater.

Key words: climate change, runoff, Mann-Kendall test, Heihe River, Qilian Mountains