Trends in potential evapotranspiration from 1960 to 2013 for a desertification‐prone region of China

Evapotranspiration is a sensitive parameter for assessing climate change. It controls energy and mass exchange and is a descriptor of drought in arid‐ and semi‐arid regions. Using the Mann– Kendall ( M–K ) test, Sen's slope estimator, and the stepwise regression, temporal, and spatial variations in potential evapotranspiration ( ET 0 ) and its dominant factors were analysed. The analysis was based on data from 173 meteorological stations in a desertification‐prone region of China over the period from 1960 to 2013. The annual ET 0 decreased prior to 1990s and increased thereafter. The majority of stations had a decreasing ET 0 trend, especially in summer, in which the average slope of all stations was −2.43 mm decade −1 . Analysis of determining factors showed that a decrease in wind speed was the primary factor associated with decreasing ET 0 . The trend magnitude of ET 0 increased from −2.25 mm decade −1 to −7.43 mm decade −1 as wind speed increased, then decreased to −3.00 mm decade −1 . Decreasing ET 0 and increasing P in the western region led to decrease in the aridity index, suggesting a wetter climate and reduced desertification. Increasing aridity index in the eastern region reduced the vegetation cover and facilitated desertification processes, which might be a disadvantage for ecological reconstruction and desertification control. Better understanding of the response of ET 0 to regional climate change may facilitate efficient use of limited water resources and establish management strategies that can combat desertification and maintain ecological security in a desertification‐prone region.