蒸散发是流域能量循环和水文循环的重要变量，准确估算蒸散发具有重要的现实意义。FAO56 Penman-Monteith方法计算潜在蒸散发量时气象资料往往不易满足，同时，在提出形式简单且满足精度要求的其它估算方法时，缺乏足够全面的适用性分析。针对上述问题，本文基于汉江流域中上游地区12个气象站点1961-2013年的逐日气象资料，以FAO56 Penman-Monteith 方法估算的潜在蒸散发量作为参考标准，分别从不同的时间尺度和空间尺度对比分析了1种综合类方法、2种辐射类方法和3种温度类方法在汉江流域的适用性。结果表明，辐射类方法适用性最好，综合类方法次之，温度类方法适用性较差。其中Makkink方法和Priestley-Taylor方法在研究区的适用性最好，计算精度高，McCloud方法在研究区的适用性最差，误差较大。
As the potential evapotranspiration (PET) is one of the important factors in the energy cycle and hydrological cycle, the accurate estimation of PET has important practical significance. The FAO56-PM method can give efficient estimation of PET; however, its applicability is constrained as it requires a large amount of data. Different PET estimation methods have been proposed and the applicability of these methods should be tested before they are applied in a typical region. In this study, we attempted to examine the efficiency of 7 PET estimation methods in spatial and temporal dimensions in the upper and middle reaches of Hanjiang River Basin using the daily meteorological data during 1961-2013. The results showed that the radiation-based methods were the optimal choice, followed by the combination method, and the temperature-based methods were the least suitable choice for the PET estimation in the study area. Among these estimation methods, the Makkink method and the Priestley-Taylor method showed the best applicability and highest precision in the study area, while the McCloud method showed the worst applicability and largest error.