## 3 Results
### MSI vs. ETM+  
The scatterplot representing the comparison between paired surface reflectance pixel values of satellites Sentinel-2 and Landsat-7 (training dataset) was reported in Figure 3. This comparison between sensors also demonstrates a good level of agreement, as evidenced by the dashed line representing the ODR slope values (Figure 3; Table 9). The blue band has a higher degree of disagreement (ODR slope, 0.7901). Nevertheless, the mean difference values for all band comparisons are statistically significant (\(p\)-value \(<\) 0.05) and the RMSD values range from 0.0196 (Blue band) to 0.0505 (SWIR1 band) (Table 9). Applying adjustment coefficients of the regression models from this study (OLS/RMA) (Table 10) and those available in the literature, by [PERSON] et al. (2019), statistical differences were appreciated (Table 11). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Regression** & **Blue** & **Green** & **Red** & **NIR** & **NIRa** & **SWIR1** & **SWIR2** \\ \hline OLS Intercept & \(-\)0.0083 & \(-\)0.0037 & \(-\)0.0041 & 0.0065 & 0.0038 & 0.0067 & \(-\)0.0083 \\ OLS Slope & 0.9375 & 0.934 & 0.9325 & 0.959 & 0.9416 & 0.9246 & 0.9375 \\ \hline RMA Intercept & \(-\)0.0119 & \(-\)0.0067 & \(-\)0.0067 & \(-\)0.0063 & \(-\)0.0054 & 0.0010 & \(-\)0.0119 \\ RMA Slope & 0.9764 & 0.9554 & 0.9464 & 1.0009 & 0.9688 & 0.9462 & 0.9764 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Intercept and slope values obtained by applying both OLS and RMA regression models for each pair of MSI surface reflectance as a function of ETM+ surface reflectance. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Band** & **OLS** & **RMA** & **[PERSON] et al. Coeff.** \\ \hline Blue & \(-\)7.68 \(\times\) 10\({}^{-6}\) & 4.40 \(\times\) 10\({}^{-5}\) & 0.0116 * \\ Green & \(1.91\times\) 10\({}^{-6}\) & 4.54 \(\times\) 10\({}^{-5}\) & 0.0026 * \\ Red & \(4.62\times\) 10\({}^{-6}\) & \(-\)1.05 \(\times\) 10\({}^{-5}\) & 0.001 \\ NIR & \(3.68\times\) 10\({}^{-5}\) & \(-\)1.24 \(\times\) 10\({}^{-5}\) & 0.0219 * \\ NIRa & \(-\)5.09 \(\times\) 10\({}^{-5}\) & \(-\)1.40 \(\times\) 10\({}^{-5}\) & \(-\)0.006 * \\ SWIR1 & \(6.16\times\) 10\({}^{-5}\) & 4.80 \(\times\) 10\({}^{-5}\) & 0.0121 * \\ SWIR2 & \(3.66\times\) 10\({}^{-5}\) & \(-\)3.22 \(\times\) 10\({}^{-5}\) & 0.0149 * \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Statistical differences in surface reflectance between the MSI and ETM+ band values after transformation functions. Mean difference (a) and RMSD values (b) for each pairwise band of the training set subjected to OLS and RMA regression models in this study and to [PERSON] et al. (2019) transformation functions. The asterisk (*) indicates the significance of the \(t\)-test, with a \(p\)-value \(<\) 0.05. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Band** & **ODR Slope** & **Mean Difference** & **RMSD** \\ \hline Blue & 0.7901 & 0.0065 * & 0.0196 \\ Green & 0.9119 & 0.0055 * & 0.0210 \\ Red & 0.9164 & 0.0083 * & 0.0274 \\ NIR & 0.9243 & 0.0156 * & 0.0422 \\ NIRa & 0.9238 & 0.0232 * & 0.0457 \\ SWIR1 & 0.9564 & 0.0273 * & 0.0505 \\ SWIR2 & 0.9251 & 0.0329 * & 0.0498 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Statistical differences in surface reflectance between the MSI and ETM+ band values. ODR slope, mean difference, and RMSD values for each pairwise band of the training set, comprising a total of 18,116 data points. The asterisk (*) indicates the significance of the \(t\)-test, with a \(p\)-value \(<\) 0.05. The coefficients available in the literature and applied to our dataset revealed statistically significant differences (\(p\)-value \(<\) 0.05) (Table 11a) for all comparisons between MSI and ETM+ bands adjusted, except for the red band. RMSD values (Table 11b) range from 0.0026 (green band) to 0.0449 (NIR band) for [PERSON] et al. [39] transformation functions. The regression models developed in this study (OLS and RMA) both improved the fitting of the data for all band pairs (Table 11).