The aim of this paper is to compare ETa estimation result using remote sensing technique with that of hydrological and meteorological model in a semi-arid Region. Specific objectives are: (1) to search about a validation method for the surface evapotranspiration estimation on the pixel scale, (2) to assess the validity of the estimation in the temporal scale. A satellite-based energy balance model (SEBAL) was employed to estimated daily and monthly ETa using multi-temporaries MODIS data. And the results were compared with two common hydrological and meteorological models. The results showed that the monthly results by SEBAL model have the higher relativity with both two methods. The correlation coefficient is R~2=0.88 with the TWB model and R~2=0.85 with the GG model. The relative error is less to the 10 percentage. The methods comparison results indicate that SEBAL model using remote sensing technique can be achieved a good outcome on the monthly scale. The results also indicate that more suitable validation models will be necessary when using the SEBAL method to estimating daily ETa.
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