Evapotranspiration Observation and Research of the Populus euphratica communities in lower reaches of the Tarim River.

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.