Estimating of Actual Crops Evapotranspiration Using Energy Balance Algorithms in Qazvin Plain

The estimation of evapotranspiration is one of the most important parameters in irrigation planning. In this research, drainage lysimeter data and three single-source energy balance, SEBAL, METRIC and SSEB and a two source energy balance algorithm, TSEB have been evaluated. Satellite imageries of MODIS, ETM + sensors were used in the years 1379-1382 according to the lysimeter data loading and OLI & TIRS sensor images in 1392-1395. It should be noted that, the mismatching of the OLI & TIRS images timing with the lysimeter data timing, cause to try to evaluate the results of OLI images with Hargreaves Sarmari equation as a superior experimental method. According to the statistical indices, the results obtained from single-source algorithms showed that the SSEB algorithm with the lowest root mean square error in MODIS, ETM + and OLI & TIRS (RMSE = 0.87, 0.41 and 0.92 mm per day), and a large correlation It was introduced with lysimeter data as the best method in this area (R = 0.97, 0.99, 0.96). Among the sensors examined, ETM +, OLI & TIRS sensitivity is high on the two sensors, but the ETM + sensor also has better results