## 3 Results
### Analyzing Productivity Simulations Under Wet Conditions  
During the wet period DOY 214-227 in 2000, VBall_WT reproduced the hourly dynamics of hummock and hollow shrubs and moss GPP (Figure 13), which were in general agreement with hourly ecosystem GPP (Figure 9a). VBall_NS had similar results (Figures 11a and 14a,b,d), except for the dynamics of hourly hollow shrub GPP, which followed a different pattern (Figure 14c), as explained below. Increased GPP from DOY 214 to DOY 215 in VBall_WT hummocks and hollows (Figure 13) and VBall_NS hummocks (Figure 14a,b) was due to increased I\({}_{\rm SWR}\) (Figure 15a) (Equations (S1.1.1.4) and (S1.1.2.2)). Although the increase in I\({}_{\rm SWR}\) continued through to DOY 218, simulated shrub GPP decreased, except on DOY 218 in VBall_WT hollows (Figures 13a,c and 14a). That de crease was due to the constraining effect of decreasing RH from DOY 215 to DOY 218 (Figure 15c) depressing \(\mathrm{g_{s}}\) (Equation (S1.1.5.5)) and reducing \(\mathrm{T_{L}}\) with decreased \(\mathrm{T_{air}}\) (Equations (S1.1.3.1), (S1.1.4.4) and (S1.1.4.6)) in the model. The decrease in simulated shrub GPP from DOY 218 to DOY 220 (Figures 13a,c and 14a) was due to decreasing \(\mathrm{I_{SWR}}\), while RH increased during this time (Figure 15a,b). As moss has no stomatal control, the \(\mathrm{I_{SWR}}\) increase with a relatively high RH on DOY 216 (Figure 15a,c) resulted in increasing moss GPP in both VBall_WT and VBall_NS hummocks and hollows (Figures 13b,d and 14b,d) in the first three days of the period (Equations (S1.2.1.1) and (S1.2.3.1)). A subsequent \(\mathrm{I_{SWR}}\) increase from DOY 221 to DOY 223 (Figure 15a) caused increases in shrub and moss GPP in hummocks and hollows in VBall_WT (Figure 13) and in shrub and moss GPP in hummocks (Figure 14a,b) and moss GPP in hollows (Figure 14d) in VBall_NS (Equations (S1.1.1.4) and (S1.1.2.2)). Figure 9: Hourly ecosystem gross primary productivity (GPP) and net primary productivity (NPP) at Mer Bleue bog during 2-15 August 2000 (**a**), 2001 (**b**), 2002 (**c**), and 2003 (**d**). Simulated GPP by VBall_WT model run driven by the observed depth to water table, \(\mathrm{d_{WT}}\), is compared vs. observed GPP derived from eddy covariance (EC) CO\({}_{2}\) exchange. DOY means day of year. shrub GPP (Figures 13a,b and 14a). Compared to shrubs, moss GPP was reduced by the low I\({}_{\text{SWR}}\) on DOY 222 (Equation (S1.2.1.1)) in both VBall_WT (Figure 13b,d) and VBall_NS (Figure 14b,d). The subsequent pronounced decline of shrub and moss GPP in hummocks and hollows on DOY 224 in both VBall_WT (Figure 13) and VBall_NS (Figure 14) was due to the significantly lower I\({}_{\text{SWR}}\) and T\({}_{\text{air}}\) that day (Figure 15a,b) and its effect on the model (Equations (S1.1.3.1), (S1.1.4.4) and (S1.1.4.6)). The stable, relatively high I\({}_{\text{SWR}}\) and T\({}_{\text{air}}\) and relatively low RH and v\({}_{\text{w}}\) (Figure 15a-d) during the last three days of the period resulted in a moderately high GPP in VBall_WT and VBall_NS (Figures 13 and 14a,b,d). Figure 11: Hourly ecosystem gross primary productivity (GPP) and net primary productivity (NPP) at Mer Bleue bog during 2–15 August 2000 (**a**), 2001 (**b**), 2002 (**c**), and 2003 (**d**). Simulated GPP by VBall_NS model run driven by the observed near-surface soil water contents, \(\theta\), is compared vs. observed GPP derived from eddy covariance (EC) CO\({}_{2}\) exchange. DOY means day of year. In VBSall_WT, d\({}_{\text{WT}}\) in hummocks was \(\sim\)34 cm below the hummock surface (Figure 15e), and d\({}_{\text{WT}}\) in hollows was \(\sim\)9 cm below the hollow surface. Thus, in unsaturated soil layers above WT, simulated \(\theta\) in hollows was higher than that in hummocks (Equation (S6.1.1.4a,b)),  
Figure 12: Daily ecosystem gross primary productivity (GPP) at Mer Bleue bog during 2-15 August 2000 (**a**), 2001 (**b**), 2002 (**c**), and 2003 (**d**), and the course of daily GPP in 2000–2004 (**e**).