## 3 Results and Discussion
### Calibration
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Rn**} & \multicolumn{2}{c}{**Rr**} & \multicolumn{2}{c}{**LE**} & \multicolumn{2}{c}{**H**} & \multicolumn{2}{c}{**NEE**} \\ \cline{2-11}  & **clb** & **def** & **clb** & **def** & **clb** & **def** & **clb** & **def** & **clb** & **def** \\ \hline
**RMSE** & 14.84 & 27.78 & 2.00 & 19.88 & 26.06 & 29.02 & 16.46 & 15.88 & 2.32 & 7.37 \\
**PBIAS** & \(-1.40\) & \(-20.00\) & \(-1.00\) & 57.00 & 2.80 & \(-13.40\) & 23.40 & \(-8.40\) & 189.20 & 739.10 \\
**MAE** & 8.59 & 24.22 & 1.40 & 17.62 & 19.29 & 21.29 & 12.45 & 12.09 & 1.90 & 6.81 \\
**NSE** & 0.94 & 0.79 & 0.98 & \(-0.53\) & 0.59 & 0.49 & 0.41 & 0.46 & \(-0.13\) & \(-10.32\) \\
**R2** & 0.94 & 0.93 & 0.99 & 0.98 & 0.64 & 0.55 & 0.62 & 0.54 & 0.52 & 0.41 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Daily average statistics of the simulated values (calibrated \(clb\) and default \(def\)) against data observed from the Santa Maria experimental site from 2014 to 2017, for net radiation (Rn), solar radiation reflected by the surface (Rr), latent heat flux (LE), sensible heat flux (H), and net ecosystem exchange of CO\({}_{2}\) (NEE). Figure 6: Average monthly albedo observed (\(obs\)), simulated by the model before calibration (\(def\)) and simulated after calibration (\(clb\)). Figure 7: Daily average latent heat flux observed (\(LE.obs\)), simulated by the model before calibration (\(LE.def\)), and simulated after the calibration (\(LE.clb\)). the daytime period. The difference between the peak \(LE.obs\) and \(LE.def\) of approximately 40 W m\({}^{-2}\) found stands out while the difference found between \(LE.obs\) and \(LE.clb\) does not exceed a value of 10 W m\({}^{-2}\). In addition, a clear trend in the model can be observed in its overestimation of \(LE\) values for the daytime values. We also highlight the good fit of the linear regression line between calibrated and observed hourly values (m = 0.94, b = 8.35, and R2 = 0.77), which is substantially better than values shown in the literature [13; 25]. Daily mean values (Figure 9) and average diurnal cycles simulated (Figure 10) for sensible heat flux, simulated with the calibrated parameters show significant improvements relative to the default simulation. However, unlike values for \(LE\), the model did not reproduce the annual seasonality of observed \(H\) for the Pampa biome. Different patterns between the simulated diurnal and nocturnal periods in relation to those observed are found. Systematic underestimations between 6 and 12 a.m. and overestimations between 1 and 6 p.m. (Figure 10). The scatter plot shows good adjustment in relation to the hourly observed data (angular coefficient 0.83, linear coefficient 12.3 and \(R2\) 0.78). It is also possible to observe a slight  
Figure 8: (**a**) Average diurnal cycle of latent heat flux observed (\(LE.obs\)), simulated by the model before calibration (\(LE.def\)), and simulated after the calibration (\(LE.clb\)); (**b**) daily \(LE\) cumulative sum by year; (**c**) scatter plot of hourly \(LE\) observed and simulated by the calibrated model. Figure 9: Daily average of sensible heat flux observed (\(H.obs\)), simulated by the model before calibration (\(H.def\)), and simulated after the calibration (\(H.clb\)). lag in simulated values covering approximately one hour at the upper peak of \(H\) and underestimations at this point of approximately 5 W m\({}^{-2}\) and 40 W m\({}^{-2}\) for \(H.clb\) and \(H.def\), respectively. Good fit of the mean daily values by year and average diurnal cycle of the \(NEE.clb\) for daytime periods (diurnal and nocturnal) can be observed in Figure 11 and Figure 12a, respectively. Values of \(NEE.def\) for the daytime period present great discrepancies in relation to the observed data. Coefficients of the regression line for hourly values present values of m = 0.75 and b = \(-1\), which are similar to the values found by [13].