A simple method to estimate basin-scale actual evapotranspiration using SEBS algorithm and global data sources (Case study: Neyshabur basin)

Actual evapotranspiration (ET) is one of the most important and complex components of the water balance. In recent years, various remote sensing techniques and algorithms have been developed which provide a cost‐effective and reliable estimate of actual ET. In this research, the spatial distribution of actual ET at the basin scale was estimated based on SEBS algorithm and world-known information data sources which are rarely used in Iran. The estimated actual ET values were compared to the results of well-known SEBAL algorithm and the SWAT hydrological model. The study shows that the SEBS algorithm has overestimated actual ET in comparison with SEBAL algorithm. The primary cause of differences between two models is in their algorithms for calculating sensible heat. Moreover, SEBS algorithm is highly sensitive to the air temperature. SEBAL is a more complex and reliable method, but it needs reliable ground-based weather data. On the other hand, SEBS does not depend on ground-based data and its results could be acceptable under limited data condition.