Abstract:
In order to investigate the temporal and spatial distribution characteristics of reference crop evapotranspiration(ET
0) 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 ET
0, and multiple regression analysis was used to quantify the contribution rate of each meteorological factor to ET
0. 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 radiation 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, ET
0 has shown a fluctuating upward trend, with an increase rate of 0.287 1 mm/a. The spatial distribution of ET
0 in the west is higher than the east with significant difference characteristics. The annual average ET
0 of 24 sites ranges from 1 100 mm to 1 200 mm in the western region, and annual average ET
0 of 18 sites ranges from 843 mm to 950 mm in the eastern region. Solar radiation is the main driving factor of ET
0 in spring, autumn and winter, and temperature is the main driving factor of ET
0 in summer in the Yunnan-Kweichow Plateau. The annual contribution rate of various meteorological factors to ET
0 throughout the year is ranked as solar radiation(R
s), air temperature(T
mean), relative humidity(RH), wind speed(u
2). Therefore, solar radiation is the dominant driving factor affecting ET
0 changes in the Yunnan-Kweichow Plateau.