Evaluation of Different Parametric Situations on Satellite SEBAL, METRIC and TVT Methods on Estimation of Actual Evapotranspiration in the Northern Ahwaz Study Region

Remote sensing (RS) data is widely applied for estimation of actual evapotranspiration (ETa) and different methods are also developed in this regard. Among them, SEBAL and METRIC as energy balance models and TVT as vegetation-based have received more attentions. However, they are based on some parameters that need to evaluate while being used. For this, 12 MODIS images for the 2008-2009 water year period that covers the Northern Ahwaz study region (based on the classification of Ministry of Energy), were prepared to be applied for estimation of ETa using the RS models. In order to evaluate and compare the results, estimation of actual evapotranspiration using the conventional water balance model was also used for the same period. Furthermore, the best estimations of ETa using RS models for alfalfa were compared with the respected values in the national water document. The results showed better performance of SEBAL and then METRIC and TVT. While, the water balance model showed 341 mm/yr of ETa, SEBAL showed it 347.24 mm/yr for the same period. However, evaluation of these parameters revealed that application of calibrated soil heat flux andMomentum roughness length equations have significant effect of its performance and reducing of the uncertainties.