## 3 Results  
### Ecological Indicators and Terrestrial Carbon Fluxes  
To illustrate the potential role of LAI parameterization in simulating the simulated terrestrial carbon fluxes, the following ecological indicators were analyzed: solar radiation absorbed by the vegetation (SABV; in W m\({}^{-2}\)), photosynthesis rate (FPSN; in \(\upmu\)mol m\({}^{-2}\)s\({}^{-1}\)), leaf carbon (LEFAC; in gC m\({}^{-2}\)) and soil temperature of depth 10 cm (ST10; in K) for 2001 to 2010 (Figure 2). From Figure 2a-c, it can be observed that LAImod has a lower SABV than the LAIorg by 40-80 W m\({}^{-2}\) over the Savanna of the Northern and Southern hemispheres, while over the evergreen forest (Congo basin region), the change is approximately 20 approaching 40 W m\({}^{-2}\). Such behavior can be explained by the fact that LAIorg severely overestimates the Total Leaf Area Index (TLAI; sum of sunlit and shaded leaves) relative to the MODIS, while LAImod alleviates this overestimation, particularly over the Savanna. Because of the noted behavior of the SABV, LAIorg reduces the FPSN by 2-4 \(\upmu\)mol m\({}^{-2}\)s\({}^{-1}\) approaching 8 \(\upmu\)mol.m\({}^{-2}\).sec\({}^{-1}\) over the Savanna of the Northern hemisphere, by 2-6 over the Savanna of the Southern hemisphere and it is \(\pm\)1 \(\upmu\)mol m\({}^{-2}\)s\({}^{-1}\) over the Congo basin (Figure 2d-f). Therefore, LAImod reduces the total carbon stored in the leaf (LEAFC) by 80-200 gC m\({}^{-2}\) over the Savanna of the Northern and Southern hemispheres and by \(\pm\)40 gC m\({}^{-2}\) over the Congo basin (Figure 2g-i). From Figure 2i-l, it can be noted that LAImod has a higher ST than LAIorg over the Savanna regions by 6-9 K and by 1-3 K over the Congo basin. Such behavior can be explained by the fact that LAIorg allows a low rate of incoming solar radiation because of high LAI. In contrast, LAImod allows a high rate of the incoming solar radiation [6]. Figure 3 shows the comparisons for GPP (defined as the total photosynthesis yield at the ecosystem scale). In general, RegCM4 is able to reproduce the spatial pattern of the GPP in comparison with the CARDAMOM in all seasons (Figure 3a-c,g-i,m-o,s-u), yet varying with the season as well as the region. For brevity in the analysis, only the spring (March-April-May; MAM) is considered for discussion. In the MAM season, it can be \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Station**} & \multirow{2}{*}{**Latitude**} & \multirow{2}{*}{**Longitude**} & \multirow{2}{*}{**V Vegetation Species**} & \multicolumn{2}{c}{**MB**} & \multicolumn{2}{c}{**SD**} & \multicolumn{2}{c}{**CORR**} \\ \cline{4-9}  & & & & **LAIorg** & **LAImod** & **LAIorg** & **LAImod** & **LAIorg** & **LAImod** \\ \hline Demokeya (SD-DEM) & 13.2829 & 30.4783 & Savanna & 5.7 & 4.16 & 2.5 & 2.47 & 0.46 & 0.44 \\ \hline Mongu (ZM-Mon) & \(-\)15.4391 & 23.2525 & Deciduous forest & 1.21 & 0.75 & 1.29 & 1.22 & 0.41 & 0.67 \\ \hline Tchizalamou (CG-Tch) & \(-\)4.2892 & 11.6564 & Savanna & 5.48 & 2.38 & 0.91 & 1.11 & 0.01 & 0.14 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The table shows a list and description of FLUXNET sites used in this study as well as statistical metrics for the model evaluations. Additionally, it shows mean bias (MB), standard deviation ratio (SD) and Pearson correlation coefficient (CORR) to quantitatively evaluate the performance of LAIorg and LAImod with respect to FLUXNET observations. noted that LAIorg overestimates the GPP over the Savanna of the Southern hemisphere by 2-5 gC m\({}^{-2}\) day\({}^{-1}\) and underestimates the GPP by 2-4 gC m\({}^{-2}\) day\({}^{-1}\) over the Congo basin and the coastal region of West Africa (Figure 3d). On the other hand, LAImod overestimates the GPP over the Savanna of the Southern hemisphere by 1-2.5 gC m\({}^{-2}\) day\({}^{-1}\) and underestimates the GPP over the Congo basin and West Africa by 3-4 gC m\({}^{-2}\) day\({}^{-1}\) (Figure 3e). LAImod has a lower GPP than the LAIorg by 1-3 gC m\({}^{-2}\) day\({}^{-1}\) overall in tropical Africa (Figure 3f).