## 2 Materials and Methods
### Validation of STEPS, SCOPE, and TSEB  
For validation, fine-quality level 2 data from 18 Integrated Carbon Observation System (ICOS) sites were downloaded from the DIBAF-ICOS portal for the year 2019. Although eddy covariance observations are available for the Mediterranean region from 1999 to 2021 across 144 sites, much of these data are not publicly accessible or are only available up to 2015 (the eddy flux sites distribution is shown in Figure 1).  
In sites where eddy covariance-based ground (G) flux data were available, energy balance closure correction was applied to validate energy balance. These validation datasets  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Product Name** & **Temporal Frequency** & **Resolution** & **Approach** & **Input Data** \\ \hline MOD16A2 & 8-days & 500 m & \begin{tabular}{c} Penman–Monteith, surface \\ conductance model \\ \end{tabular} & \begin{tabular}{c} MERRA 2 Meteorology, MODIS LAI, \\ landcover, albedo, emissivity \\ \end{tabular} \\ \hline GLEAM & Daily & 25 km & \begin{tabular}{c} Priestly–Taylor Equation, \\ soil stress factor \\ \end{tabular} & \begin{tabular}{c} Air T (ERA-Interim, AIRS) net \\ Radiation (CERES), TRMM for \\ precipitation, Dynamic LC, Veg \\ Optical Depth (Microwave \\ RS-LPRM), Surface Soil Moisture \\ (SMOS, ESA CCI) \\ \end{tabular} \\ \hline Terra Climate & Monthly & 4 km & \
\begin{tabular}{c} Modified Thornwaite \\ Mather one-dimensional \\ water balance model \\ \end{tabular} &
\begin{tabular}{c} GridMET (WorldClim climate data, \\ Climate Research Unit (CRU) and \\ Japanese 55-year reanalysis (JRA55) \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 7: Characteristics of Global ET products used as reference datasets in this study.  
Figure 1: The figure shows the study area, locations of seven AOIs colored in blue capturing major land use types of Mediterranean countries, and locations of eddy covariance sites in purple from where ground ET is retrieved for validating the results.  
were screened for missing values, and the screened LE flux was multiplied with a conversion factor (the latent heat of vaporization) to obtain ET values in millimeters per day.  
\[\text{ET}_{\frac{\text{mm}}{\text{d}}}=\text{LE}\times 2.5\text{ MJ} \tag{1}\]  
The daily ET pixels of models were validated against ground-based ET flux measurements to assess model performance in specific ecosystems and compare their differences at sites and regional scales. For this statistical comparison, the determination of coefficients (r\({}^{2}\)), root mean square error (RMSE), and mean bias error (MBE) were calculated to find the agreement between the model-based estimates and EC measurements. They were calculated as follows:  
\[\text{r}^{2}=\frac{\sum_{\text{i}=1}^{\text{N}}(\text{ET}_{\text{estimated,i}}- \text{mean}_{\text{ET}_{\text{measured}}})^{2}}{\sum_{\text{i}=1}^{\text{N}}( \text{ET}_{\text{measured,i}}-\text{mean}_{\text{ET}_{\text{measured}}})^{2}} \tag{2}\]  
\[\text{RMSE}=\sqrt{\frac{1}{\text{N}}\sum_{\text{i}=1}^{\text{N}}\left|\text{ ET}_{\text{estimated,i}}-\text{ET}_{\text{measured,i}}\right|^{2}} \tag{3}\]  
\[\text{MBE}=\frac{1}{\text{N}}\sum_{\text{i}=1}^{\text{N}}(\text{ET}_{\text {estimated,i}}-\text{ET}_{\text{measured,i}}) \tag{4}\]