Evapotranspiration (ET) is an essential component of watershed hydrological cycle. Spatial-temporal variations analyses of evapotranspiration and potential evapotranspiration (PET) have remarkable theoretical and practical significances for understanding the interaction between climate changes and hydrological cycle and optimal allocation of water resources under global warming background. The MODIS-estimated ET agreed well with basin evapotranspiration from water balance principle methods in the study. The spatiotemporal variations results based on MOD16 ET data showed the following: (1) multiyear mean ET and PET were 464.2 mm and 1192.2 mm, and annual ET showed an upward trend at a rate of 3.48 mm/a, while PET decreased significantly at a rate of −8.18 mm/a. The annual ET trend showed a complemental relationship with PET; (2) at the seasonal scale, ET was highest in summer and least in winter, while PET was higher in spring and summer. The change of ET and PET in spring and summer had a great contribution to the annual variations; (3) ET and PET in the northern part were significantly stronger than those in the western and southern parts; (4) ET in cropland increased significantly, while PET decreased obviously in grass and forest; (5) changes of ET and PET were closely related to climatic factors. The rise in temperature caused the increase in ET and the decrease of wind speed contributed more to the decrease in PET. The results can provide a scientific basis for water resources planning and management.

中文翻译：

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基于MOD16 ET数据的Tao河上游2001〜2018年地面蒸散量的时空变化。

蒸散量（ET）是流域水文循环的重要组成部分。蒸散量和潜在蒸散量（PET）的时空变化分析对于理解全球变暖背景下气候变化与水文循环之间的相互作用以及水资源的优化配置具有重要的理论和实践意义。MODIS估计的ET与研究中水平衡原理方法得出的盆地蒸散量非常吻合。基于MOD16 ET数据的时空变化结果表明：（1）多年平均ET和PET分别为464.2 mm和1192.2 mm，年ET呈上升趋势，速率为3.48 mm / a，而PET显着下降。速率为-8.18 mm / a。年度ET趋势显示与PET有互补关系。（2）在季节尺度上，夏季的ET最高，冬季最少，而春季和夏季的PET较高。春季和夏季，ET和PET的变化对年变化有很大贡献。（3）北部的ET和PET明显强于西部和南部的ET和PET；（4）农田和草木中的ET显着增加，而PET和PET显着下降；（5）ET和PET的变化与气候因素密切相关。温度的升高导致ET的增加，而风速的降低则对PET的降低做出了更大的贡献。研究结果可为水资源规划与管理提供科学依据。春季和夏季，ET和PET的变化对年变化有很大贡献。（3）北部的ET和PET明显强于西部和南部的ET和PET；（4）农田和草木中的ET显着增加，而PET和PET显着下降；（5）ET和PET的变化与气候因素密切相关。温度的升高导致ET的增加，而风速的降低则对PET的降低做出了更大的贡献。研究结果可为水资源规划与管理提供科学依据。春季和夏季，ET和PET的变化对年变化有很大贡献。（3）北部的ET和PET明显强于西部和南部的ET和PET；（4）农田和草木中的ET显着增加，而PET和PET显着下降；（5）ET和PET的变化与气候因素密切相关。温度的升高导致ET的增加，而风速的降低则对PET的降低做出了更大的贡献。研究结果可为水资源规划与管理提供科学依据。（5）ET和PET的变化与气候因素密切相关。温度的升高导致ET的增加，而风速的降低则对PET的降低做出了更大的贡献。研究结果可为水资源规划与管理提供科学依据。（5）ET和PET的变化与气候因素密切相关。温度的升高导致ET的增加，而风速的降低则对PET的降低做出了更大的贡献。研究结果可为水资源规划与管理提供科学依据。