## 3 Results
### Daily and Monthly Reco  
We evaluated Reco (ecosystem respiration) by comparing modeled (MD) and observed (EC) daily and monthly time series. Daily \(R\) ranged between 0.45 in ITCpz and 0.9 in FIHyy (Table 7). RMSE was of 1.28 gC m\({}^{-2}\) day\({}^{-1}\) on average, and MEB ranged between 0.43 and 1 gC m\({}^{-2}\) day\({}^{-1}\). Most of the bias happened in summer, where Reco was generally overestimated, especially in ITCol and ITCpz. NSE was positive in any case but ITCpz. It was generally lower in DBF (0.32), and higher in FIHyy (0.60) and FRPue (0.57). Reco at monthly timescale was strongly improved in predictability, especially for ITRen, whose \(R\) increased to 0.67 and NSE to 0.84. Monthly predictions showed improvements for the other simulations too, improving R and NSE of about 0.07. Since most of the bias occurred in summer, monthly predictions showed no dramatic improvements for neither RMSE nor MEB. The only exception was ITRen, whose RMSE reduced of about 0.4 gC m\({}^{-2}\) day\({}^{-1}\), suggesting that daily Reco may be noisy.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Version** & **ITRen** & **FRPue** & **DEHai** & **FIHyy** & **Avg** \\ \hline Daily & 5.1 & 0.81 & **0.82** & 0.92 & 0.91 & **0.87** \\ \(R\) & PSM & **0.88** & 0.64 & **0.93** & 0.91 & 0.85 \\ Monthly & 5.1 & 0.95 & 0.64 & 0.97 & 0.96 & 0.89 \\ \(R\) & PSM & **0.96** & **0.84** & **0.98** & 0.96 & **0.94** \\ Daily & 5.1 & 0.61 & \(-\)0.54 & 0.84 & **0.87** & 0.45 \\ NSE & PSM & **0.72** & **0.09** & **0.96** & 0.76 & **0.63** \\ Monthly & 5.1 & 0.91 & \(-\)0.11 & 0.94 & 0.91 & 0.66 \\ NSE & PSM & 0.91 & **0.56** & **0.98** & **0.92** & **0.84** \\ Daily & 5.1 & 2.09 & **1.52** & **1.85** & **1.56** & 1.76 \\ RMSE & PSM & **1.59** & 1.96 & 1.91 & 1.57 & 1.76 \\ Monthly & 5.1 & 0.97 & **1.01** & 1.07 & 0.91 & 0.99 \\ RMSE & PSM & **0.82** & 1.09 & **0.82** & **0.93** & **0.92** \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparisons between 3D-CMCC-FEM 5.1 (5.1) and 3D-CMCC-PSM (PSM) versions, using the same parameterization for 4 out of 6 sites (ITRen, FRPue, DEHai, FIHyy). As stated in Table 3, R and NSE are dimensionless; RMSE is gC m\({}^{-2}\) day\({}^{-1}\). Bold values represent best performing version.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **DEHai** & **ITCol** & **FIHyy** & **ITRen** & **ITCpz** & **FRPue** & **Mean** \\ \hline \multicolumn{8}{c}{Daily Reco} \\ \hline R & 0.79 & 0.71 & 0.90 & 0.67 & 0.45 & 0.86 & 0.73 \\ NSE & 0.32 & 0.32 & 0.60 & 0.34 & \(-\)0.43 & 0.57 & 0.29 \\ RMSE & 1.29 & 1.83 & 1.18 & 1.03 & 1.65 & 0.70 & 1.28 \\ MEB & 0.63 & 1.00 & 0.43 & 0.62 & 0.98 & 0.48 & 0.69 \\ \hline \multicolumn{8}{c}{Monthly Reco} \\ \hline R & 0.86 & 0.79 & 0.96 & 0.84 & 0.54 & 0.93 & 0.82 \\ NSE & 0.40 & 0.37 & 0.66 & 0.69 & \(-\)0.40 & 0.67 & 0.40 \\ RMSE & 1.10 & 1.67 & 1.04 & 0.64 & 1.49 & 0.54 & 1.08 \\ MEB & 0.60 & 0.99 & 0.41 & 0.50 & 1.04 & 0.43 & 0.66 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Daily and Monthly Validation statistics for R\({}_{\text{eco}}\) calculated on the test-set. As stated in Table 3, R and NSE are dimensionless; RMSE and MAB are gC m\({}^{-2}\) day\({}^{-1}\).