Evapotranspiration products Assessment using FAO-Penman-Monteith method in Zayandehrood Basin

Evapotranspiration is one of the most important parameters of the water cycle that its correct estimation is important in water resources management, especially in arid and semi-arid climates. With the development of remote sensing, methods were developed to produce evapotranspiration products using satellite data. In this study, the output of evapotranspiration products including GLEAM, GLDAS, and MOD16A2 was compared with the evapotranspiration of the FAO-Penman-Monteith method During wet, normal and dry years in the Zayandehrood basin. , RMSE, BIAS, and IOA statistical indices were used to evaluate the results. Also, Taylor simple skill fusion method was also used to combine the product. The results showed that two products MOD16A2 and GLDAS estimated the rate of reference evapotranspiration compared to the FAO-Penman-Monteith method during the wet, normal and dry years and the GLEAM product less. RMSE values for these products ranged from 37.4 to 47.6, from 136.2 to 141.4, and from 92.8 to 98.7 mm per month, respectively. The error rates of GLEAM and GLDAS were lower in the wet years than in the dry and normal years, while the MOD16A2 product had better performance in the dry years. Also, the results of the products combination showed that the product produced had a better performance than other products in the Basin and in different moisture conditions.