Abstract
Approximating the evapotranspiration is one of the most difficult parts of the hydrologic cycle. However it plays a very important role in the water balance equation. In the present study, the SEBAL model has been revalidated as an approved and successful approach for calculating the evapotranspiration. In SEBAL model, the evapotranspiration is the unknown value in the equation of surface energy balance for the land surface. Considering the differences in the calibration of LDCM compared to the previous generations of the Landsat satellite, the SEBAL model was reexamined in some especial parts. In order to test of the usefulness of SEBAL model over LDCM, the measured values was compared with the values obtained via Penman-Monteith method in 20 different days. ET estimated by SEBAL compared with PM ET was found to correlate significantly as R2 (0.7) with the correlation coefficient of 0.83. Hence the results of this analysis outline that actual evapotranspiration data can be calculated and mapped in large areas and with high reliability without the need for meteorological information periodically and regularly.
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