Evaluation of the SEBS for upscaling the evapotranspiration based on in-situ observations over the Tibetan Plateau

Evapotranspiration (ET) is a boundary condition for regional scale hydrological and climatological modeling. Spatial knowledge of land surface ET is of principal interest for environmental evaluation especially in semi-arid regions. The study used the Surface Energy Balance System (SEBS) model based on Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing and field observations data that have been used and tested for deriving ET over the NamCo area in the Tibetan Plateau, located in the southwest of China. Two ASTER scenes were used for estimating the ET over the study area. To validate the proposed methodology, the ground-measured ET was compared to the ASTER derived ET values for the study area. The results show that the derived ET in different months over the study area is in good accordance with the in-situ data. The derived ET value over the study area is much closer to the field measurement; the RMSE is 0.7 mm/d. It is therefore concluded that the SEBS methodology is successful for the retrieval of ET using the ASTER and in-situ data over the study area.