中文摘要：

本文结合涡度相关技术的实际观察数据，运用Penman—Monteith公式，估算了塔里木河下游以胡杨为主体的荒漠河岸林潜在蒸散发量，并与实际蒸散发进行了对比分析。结果表明，研究区潜在蒸散发量日变化相差较大，最大最小值之间相差约3倍；平均气温、地表净辐射、平均饱和水汽压与潜在蒸散发量变化有较好的相关性，是影响潜在蒸散发量变化的主要因素；研究区日实际蒸散量呈波动变化趋势，与地表净辐射变化有较好的相关性；降雨对实际蒸散发有明显影响，降雨后实际蒸散发量比降雨前实际蒸散发量明显增加。

英文摘要：

Combining the actual observation data of eddy covariance technique, potential evapotranspiration of the desert riparian forest is estimated in the lower reaches of tarim river that Populus Populus euphratica is the main plant species, and compared with the actual evapotranspiration by using Penman - Monteith formula. The results show that the potential evapotranspiration of diurnal variation is a larger difference , about 3 times of difference between the maximum and minimum value ; the main factor of affecting the potential evapotranspiration change is average temperature, surface net radiation, the average saturation vapor pressure and the changes of potential evapotranspiration, there is a good correlation between them;daily actual evapotranspiration of the study area have a good correlation with the change of rainfall on the surface net radiation that showing the fluctuation trend ; the rain has a significant effect on the actual evapotranspiration, actual evapotranspiration in the after rainfall increased obviously than before rainfall.