Comparing the Results of Actual Evapotranspiration from SEBAL and METRIC Models Using MODIS and ETM+ Sensor Images

Increasing crop production depends on the supply crop water demands, thus accurate estimation of crop water demands helps not only to crop production, but also is effective in the management of water resources. SEBAL and METRIC algorithms are the most widely used methods for estimating evapotranspiration as a residual of the energy balance with using remote sensing data. Based on this, the purpose of the present research was to investigate the results of actual evapotranspiration of crop from SEBAL and METRIC models in the Qazvin plain. To evaluate the results of actual evapotranspiration, two sensors with different temporal and spatial resolution (images of MODIS sensor Terra satellite and ETM sensor Landsat 7 satellite) were used. In this regard, Qazvin weather station data as well as data Lysimeter were used in order to verify the results of METRIC and SEBAL algorithm. The results of METRIC and SEBAL models with a total of 10 images obtained from MODIS sensor Terra satellite and ETM sensor Landsat 7 satellite were evaluated with data Lysimeter for grass reference crop in 1380. MODIS sensor with r=0.88, RMSE=1.91 and SE=0.85 mm/day with r=1.00, RMSE=0.91 and SE=0.09 in METRIC model compared with the SEBAL model estimates are more accurate than the lysimeter operation and in this research recommended as a top model for estimating actual evapotranspiration in the Qazvin plain.