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| Spatial-temporal distribution characteristics and attribution analysis of reference crop evapotranspiration in Yunnan-Kweichow Plateau |
| LIU Quanshan1, WU Zongjun1, CUI Ningbo1,2,3*, ZHU Shidan1, ZHENG Shunsheng1 |
| 1. State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China; 2. Provincial Key Laboratory of Water-saving Agriculture in Hill Areas of Southern China, Chengdu, Sichuan 610066, China; 3. Key Lab for Crop Water Requirement and Regulation of Ministry of Agriculture, Farmland Irrigation Research Institute, Chinese Academy of Agriculture Sciences, Xinxiang, Henan 453000, China |
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Abstract In order to investigate the temporal and spatial distribution characteristics of reference crop evapotranspiration(ET0)in the Yunnan-Kweichow Plateau, based on the daily meteorological data of 42 representative meteorological stations in the Yunnan-Kweichow Plateau in recent 56 years(1961—2016). Mann-Kendall test was used to explore the main meteorological driving factors of ET0, and multiple regression analysis was used to quantify the contribution rate of each meteorological factor to ET0. The results show that: the wind speed and temperature have increased year by year during the past 56 years, with the increase rate of 0.001 2(m·s-1)/a and 0.018 °C/a, respectively. The solar ra-diation and relative humidity have shown a downward trend, with the decrease rate of 0.007 3(MJ·m-2·d-1)/a and 0.074 6%/a, respectively, in the Yunnan-Kweichow Plateau. Over the past 56 years, ET0 has shown a fluctuating upward trend, with an increase rate of 0.287 1 mm/a. The spatial distribution of ET0 in the west is higher than the east with significant difference characteristics. The annual average ET0 of 24 sites ranges from 1 100 mm to 1 200 mm in the western region, and annual average ET0 of 18 sites ranges from 843 mm to 950 mm in the eastern region. Solar radiation is the main driving factor of ET0 Plateau in spring, autumn and winter, and temperature is the main driving factor of ET0 in summer in the Yunnan-Kweichow. The annual contribution rate of various meteorological factors to ET0 throughout the year is ranked as solar radiation(Rs)> air temperature(Tmean)> relative humidity(RH)> wind speed(u2). Therefore, solar radiation is the dominant driving factor affec-ting ET0 changes in the Yunnan-Kweichow Plateau.
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Received: 25 May 2021
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