Daily Actual Evapotranspiration Estimation in a Mediterranean Ecosystem from Landsat Observations Using SEBAL Approach

Quantifying actual evapotranspiration (ETa) over natural vegetation is crucial in evaluating the water status of ecosystems and water-use patterns local or regional hydrological basins. Remote sensing-based surface energy balance models have been used extensively for estimating ETa agro-environments; however, application these to still limited. The algorithm land (SEBAL) physical-based model was applied estimate a heterogeneous coverage Mediterranean maquis reserve Sardinia, Italy. on 19 Landsat 5 8 images from 2009 2014, results were compared data micrometeorological station with eddy covariance flux measurements. Comparing SEBAL-based evaporative fraction (ΛS) corresponding tower-derived fractions (ΛT) showed good estimations overpass time (Coefficient determination R2 = 0.77, root mean square error RMSE 0.05 absolute MAE 0.076). Three methods evaluated upscaling instantaneous latent heat (λE) daily (ETa,D). use (Λ), reference (EFr) ratio incoming shortwave radiation (Rs24/Rsi) as factors under hypothesis diurnal self-preservation. A preliminary analysis performed using only in-situ measured demonstrated that three relatively self-preserved during daytime, can yield ETa,D estimations, particularly when obtained at near scene acquisition (≈10:00 UTC). SEBAL retrieved fluxes, some ancillary meteorological upscale SEBAL-estimated λ ET. Λ EFr Rs24/Rsi average overestimated by nearly 20, 61 18%, respectively. performance considered satisfactory, bearing mind high variable ground cover inherent variability biome composition, which cannot be properly represented moderate spatial resolution. In this study, we tested potential complex ecosystem. This modeling approach will represent dynamics ET, integrated into further environmental applications.