3. Results
3.1 Temporal variation of environmental variables
The daily variations in precipitation, air temperature, land surface evaporation, and humidity in the study area from May 2018 to June 2019 are presented in Fig. 3. The daily precipitation ranged from 0.01 mm to 146.4 mm. During the rainy season, the cumulative rainfall was 1079.49 mm, which accounted for 64.7% of the total rainfall during the test period, and the average daily rainfall was 8.7 mm. During the test, the daily temperature ranged from −2.38 °C to 32.67 °C, and the average daily temperature was 18.48 °C. The daily relative humidity ranged from 39.78% to 98.79%, and the daily average relative humidity was 74.53%. The daily evaporation ranged from 0.36 mm to 7.07 mm, and the average daily evaporation was 2.8 mm. The daily evaporation trend was consistent with that of the temperature. The evaporation in the rainy season was 755.69 mm, which accounted for 63.43% of the total evaporation, thus reflecting the rapid evaporation of atmospheric precipitation driven by the temperature in the rainy season.