Modeling potential evapotranspiration based on energy balance

To investigate a more accurate method for potential evapotranspiration estimation under climate change, three sets of experiments were conducted using small lysimeters at Wudaogou experimental station on the Huaibei Plain (China), and a new model of potential evapotranspiration was proposed by integrating the advection dynamics term and introducing a correction parameter for surface net radiation fluxes on the basis of the energy balance principle. The results revealed the following: ① The correlation between evapotranspiration of the grass cover group (E14 and E25) with different measurement methods was better (R=0.95) among the three sets of experiments. ② The Nash-Sutcliffe efficiency coefficient (0.85) and root mean square error (0.83) of the proposed potential evapotranspiration model were better than those of existing empirical methods such as the Penman equation in the two experiments covered with gras. ③ The model demonstrated capability for estimation of evapotranspiration under grass cover and marked advantages in its application to the Huaibei Plain area. The proposed model can improve the accuracy of regional potential evapotranspiration simulation, and provide scientific reference for water cycle process simulation and water resources utilization.