There are different algorithms to estimate the energy balance equation. This equation expresses net radiation converting to other forms of radiation fluxes. Thus, the equation consists of the net radiation (Rn), sensible heat flux (H), latent heat flux (λE), and soil heat flux (G). The computation of the equation is helpful to consider energy exchange between the atmosphere and the surface. Therefore, testing different methods could help us in finding a more accurate way to estimate the energy balance equation. The simple algorithm for evapotranspiration retrieving (SAFER) algorithm is a method to estimate energy balance equation parameters. Mashhad area in northeast of Iran located in a semiarid region was chosen as the study area. Rn, H, λE, and G were calculated by the SAFER algorithm (method 1). In addition, Rn, H, λE, and G were computed based on a theoretical formula (method 2). Surface albedo (α0) and surface temperature (T0) were the two input parameters used in both methods. In method 1, α0 and T0 values are spatially distributed in Mashhad while they are constant values in method 2. The results of method 1 and method 2 were compared. The obtained results showed 2 Mjm−2 d−1 differences for Rn, H, and λE variables in both methods. Albedo and surface temperature values that were spatially distributed in method 1 lead to a wide variation range in the calculated energy terms. However, these parameters, which were considered as constant values, made energy terms have limited variation range in method 2. Therefore, the differences in the obtained results between the two methods were resulted from α0 and T0 values. The differences in the values were insignificant in the large-scale calculation, which can be ignored. The SAFER algorithm showed acceptable results in the semiarid of Mashhad region. This algorithm can be used for energy balance equation estimation in Mashhad.

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