## 2 Materials and Methods
### Sentinel-2  
The Sentinel-2 satellites are under the care and operation of the European Space Agency (ESA), an intergovernmental organization representing 22 European countries. The management of the Sentinel satellite missions falls within the purview of the Copernicus Programme. This satellite constellation comprises two units, Sentinel-2A (S2A) and Sentinel-2B (S2B), taking Earth's landscape images at noon. Each of these satellites takes multispectral image scenes, covering an area of 290 km by 290 km. They orbit the Earth, providing imagery every 10 days for a single satellite device around the equator. When both satellites are combined, this interval shortens to 5 days. For areas located at mid-latitudes, such as the LIRF and IIC research facilities, the revisiting time is as frequent as every 2 to 3 days near local noon time. Additional details concerning the satellite's design, operation, and components can be found in the work of ([PERSON] et al., 2014). Both the S2A and S2B satellites follow sun-synchronous orbits, maintaining an average altitude of 786 km, with equator crossings occurring around noon local time (12 p.m.). It is important to note that Sentinel-2 satellites currently do not provide thermal imagery. The spatial resolution of Sentinel-2 images varies and depends on the specific multispectral bands in use, ranging from 10 m to 60 m. For this study, we have considered only Sentinel-2 bands 2, 3, 4, and 8, which offer a spatial resolution of 10 m, as these bands are provided at their original spatial resolution, as documented in Table 4.  
The original radiometric resolution of Sentinel-2 images is 12 bits. However, ESA enhances these images to a 16-bit radiometric resolution through post-processing. Sentinel-2 Level-2 images undergo calibration and pre-processing, aiming to provide ground-based surface reflectance. The surface reflectance images provided (downloaded) include a scaling factor of 10,000. To obtain surface reflectance decimal values, the Sentinel downloaded images are divided by 10,000. The atmospheric corrections are carried out using a radiative transfer algorithm developed by ESA, known as Sen2 Cor. For details regarding the use \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Bands** & **Central Wavelength (nm)** & **Bandwidth (nm)** & **Spatial Resolution (m)** \\ \hline BLUE & 492 & 66 & 10 \\ \hline GREEN & 560 & 36 & 10 \\ \hline RED & 665 & 31 & 10 \\ \hline NIR & 833 & 106 & 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Sentinel-2 multispectral bands used in this study at LIRF and IIC research sites. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Bands** & **Central Wavelength (nm)** & **Bandwidth (nm)** & **Spatial Resolution (m)** \\ \hline BLUE & 480 & 60 & 30 \\ \hline GREEN & 560 & 60 & 30 \\ \hline RED & 655 & 30 & 30 \\ \hline NIR & 870 & 30 & 30 \\ \hline LWIR & 1090 & 60 & 100 (Resampled to 30) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Landsat-8 multispectral bands used in this study at both LIRF and IIC sites. of Sen2 Cor in atmospherically correcting S2A and S2B satellite images, refer to the work of [43]. The pixels that contained the stations of measurements for each research site were considered representative for the calculations of maize ET\({}_{\text{a}}\) using the TSEB approaches. Planet CubeSat is a cost-effective commercial constellation of micro (Dove) satellites, managed by Planet Labs, Inc. in San Francisco, California, USA. Comparising over 130 CubeSat units, these satellites observe Earth's landscapes, providing high temporal (daily) and spatial resolutions (3 m). Planet CubeSat microsatellites capture multispectral imagery in the visible and near-infrared (NIR) portions of the light spectrum. The radiometric resolution of Planet CubeSat imagery starts at 12 bits during image acquisition but is enhanced to a 16-bit resolution through post-processing before it is made accessible for download.