Spatio-Temporal Assessment of Global Gridded Evapotranspiration Datasets across Iran

Estimating evapotranspiration (ET), the main water output flux within basins, is an important step in assessing hydrological changes and availability. However, direct measurements of ET are challenging, especially for large regions. Global products now provide gridded estimates at different temporal resolution, each with its own method estimating based on various data sources. This study investigates differences between ERA5, GLEAM, GLDAS datasets estimated points across Iran, their accuracy comparison reference ET. The spatial discrepancies identified, as well co-variation forcing variables. values used to check were balance (ETwb) from Iran’s errors product drivers results indicate that ETERA5 provides higher base average lower maximum annual than ETGLEAM. Temporal scale similar datasets, but seasonal monthly time scales identified. Some also recorded distribution, generally, all similarities, e.g., humid regions basins. has a correlation available energy water, while ETGLEAM ETGLDAS does not correlate none these drivers. Based ETwb, both have provided over under estimations northern southern respectively, compared them (ETERA5 ETGLEAM). All three better (values closer ETWB) hyper-arid arid central eastern Iran areas. Thus, more suitable rather basins Iran.