## 2 Materials and Methods  
### Common Inputs for STEPS, SCOPE, and TSEB  
In the first step, daily meteorological data are prepared by aggregating the hourly 5 th generation ECMWF Reanalysis for the Global Climate and Weather data (ERA5), United Kingdom [34] in the Google Earth Engine (GEE) platform. These data are used as a common meteorological input for all models. ERA5 is chosen due to its global coverage and efficacy for data-sparse areas. Some discrepancies observed in the ERA5 repository in GEE led us to cross-check a portion of ERA5-Land data \"ECMWF/ERA5_LAND/HOURLY\" against the official Copernicus Climate Data Store for consistency. The pre-processing of ERA5 was carried out following the method in [35]. For TSEB, hourly ERA5 weather data [air temperature, wind speed, and vapor pressure forcing] and LST from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI), France on board the Meteosat Second Generation MSG were used to calculate instantaneous ET at 12:00 UTC, using Sentinels for the ET method (Sen-ET). These hourly variables are processed at the 100 m atmospheric blending height above the surface. TSEB also uses a different source of radiation data. Both instantaneous and daily average downward shortwave radiation input of TSEB are from MSG, i.e., the Total and Diffuse Downward Surface Shortwave Flux product ([[https://landsaf.ipma.pt/en/products/longwave-shortwave-radiation/mdssftd/](https://landsaf.ipma.pt/en/products/longwave-shortwave-radiation/mdssftd/)]([https://landsaf.ipma.pt/en/products/longwave-shortwave-radiation/mdssftd/](https://landsaf.ipma.pt/en/products/longwave-shortwave-radiation/mdssftd/))) accessed on 1 November 2022. Their daily average is used to upscale the TSEB's instantaneous ET to a daily ET following the method in [36]. For STEPS, we used daily maximum, minimum, and average temperature (\({}^{\circ}\)C), median dew point (\({}^{\circ}\)C), total precipitation (mm), wind speed (ms\({}^{-1}\)), and total short-wave radiation (Wm\({}^{2}\)). A list of these datasets is in Table 1 showing input variables for each model. \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Variable** & **Dataset** & **Units** & **STEPS** & **TSEB** & **SCOPE** \\ \hline Shortwave incoming radiation & ERA5 SW incoming & Wm\({}^{2}\) & + & - & + \\ \hline Longwave incoming radiation & ERA5 LW incoming & Wm\({}^{2}\) & + & - & + \\ \hline Land Surface Temperature & SEVIRI LST@12:00 & \({}^{\circ}\)C & - & + & - \\ \hline Leaf Area Index & SEVIRI MSG LAI & m\({}^{2}\)/m\({}^{2}\) & - & + & - \\ \hline Total Downwelling Surface Short-wave & MSG Total and diffuse downward & Wm\({}^{2}\) & - & + & - \\ Radiative flux & Surface shortwave flux product & & & \\ \hline Dewpoint temperature at 2 m above & ERA5 Dewpoint\_T\_2 m & \({}^{\circ}\)C & + & - & + \\ the surface & & & & \\ \hline Temperature of the soil in layer (7–28 cm) & ERA5 Soil Temperature\_7\_28 cm & \({}^{\circ}\)C & + & - & - \\ \hline Highest Leaf Area Index observed & MODIS\_LAImax & m\({}^{2}\)/m\({}^{2}\) & + & - & + \\ \hline Soil Depth & Soil Depth (Soil Grids ISRIC) & cm & + & - & - \\ \hline Soil Texture & Soil Texture (Soil Grids ISRIC) & \(-\) & + & - & - \\ \hline Land use land cover by the European & & & & - & - \\ Space Agency (ESA) & ESA World cover 100 m & \(-\) & + & - & - \\ \hline Land use land cover by the Global Land & & & & \\ Cover by National Mapping & GLCNMO\_LULC & \(-\) & - & + & - \\ Organizations (GLCNMO) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: ERA5: hourly climate datasets and other surface parameters used in three models input listed with their names and units.