Evaluation of Estimated Actual Evopotranspiration of Winter Wheat Using METRIC and SEBS Models in Gareh Bygone Plain, Southern Iran

Water resources management is a complicated specialty that requires accurate datasets. Evapotranspiration (ET) plays a key role in these datasets, but using traditional methods for its estimation and lacking large-scale spatially distributed methods reduce the desirable accuracy. In order to overcome the limitations imposed by point wise calculation, remote sensing based methods have been developed. In this study, a regional ET map was produced for an area in the Gareh bygone Plain, using METRIC (Mapping Evapotranspiration at High Resolution using Internalized Calibration), a remote sensing based ET algorithm and meteorological data measured at two weather stations. For this purpose, Landsat 5 Thematic Mapper images acquired between December 2009 to July 2010 were used. Performance of the ET model was evaluated by comparing predicted daily ET with measured applied water at different irrigated fields covering 1234 ha. Comparing the seasonal results acquired from METRIC showed 4.5% error in estimations. It is also concluded that missing images between intervals can influence seasonal evapotranspiration depending on the physiology growth stage and referenced ET values. Generally, Good agreement was found between the remote sensing based ET (METRIC and SEBS) and soil water budget ET.