中文摘要：

验证参考作物蒸散量模拟方法的适用性，对于加强水资源管理和指导生态建设具有重要理论意义和应用价值。根据黄河上游地区50a来10个站点的逐日气象资料，以FAO推荐的Pen—man—Monteith（P—M）方法为标准，验证11种参考作物蒸散量计算方法在该区域的适用性。分别在月尺度和年尺度计算了各方法与P—M方法之间的相关性和均方根误差，结果表明：基于辐射的Priestley—Taylor和Makkink方法与P—M方法具有一致性，在黄河上游地区具有较好的应用前景；Priestley—Taylor方法更适宜于在月尺度上计算整个区域的参考作物蒸散量，而Makkink方法在高寒地区的生长季的适用性更强。基于温度的Thornthwaite、McCloud、Blaney—Criddle和Holdridge方法在黄河上游地区的适用性较差，低估了EL，主要原因是其无法反映研究区域气温低但辐射强的气候特征。

英文摘要：

Evapotranspiration is a complex process and the only term that appears in both a water balance equation and a land surface energy balance equation. It is practically and scientifically significant for water resources management and ecological restoration to evaluate the applicability of reference crop evapotranspiration （ETo） models. Based on the daily data of ten weather stations across a large climatic gradient in the headwater catchment of the Yellow River basin, China for recent 50 years, ETo was estimated with twelve different models, included FAO56 Penman-Monteith （P-M） , Hargreaves-Samani, Turc, Irmak-Allen, Jensen-Haise, Priestley-Taylor, Makkink, Hamon, McCloud, Blaney-Criddle, Thornthwaite, and Holdridge methods. The first five methods are based on com- prehension of temperature and radiation, and the Priestley-Taylor and Makkink are based on radiation, the last five methods are based on temperature. The climate data include maximum and minimum temperature and daily mean air temperature at 2 m height above the ground, wind speed, relative humidity, sunshine hours provided by the National Climate Center of the China Meteorological Administration. The western and southern of the study area is located in the Qinghai-Tibet Plateau; the eastern of the study area has some characteristics of the Loess Plateau, so an accurate estimate of reference crop evapotranspiration is the important work for the trend analysis of regional ecological changes and assessment of water resources. The P-M approach was recommended by FAO as the sole standard tool to calculate ETo and is a physically based technique and can be used globally without any need for additional ad- justments of parameters. Taking P-M equation as the standard for evaluating the other methods, the linear regression and root mean squared error between P-M equation and the other simple equations were calculated, the results show that the best relationship and minimal difference were obtained with Priestley-Taylor or Makkink method, which is the best