## 2 Materials and Methods
### Model Experiments
\begin{table}
\begin{tabular}{c l c c} \hline \hline
**Quantiy 1** & **Meaning** & **Value** & **Units** \\ \hline D\({}_{\text{TI}}\) & Energy of deactivation for electron transport rate & 200,000 & J mol\({}^{-1}\) \\ \hline E\({}_{\text{SCO}}\) & Activation energy for decline in Rubisco affinity for CO\({}_{2}\) with T & \(-\)24,460 & J mol\({}^{-1}\) \\ \hline E\({}_{\text{TC}}\) & Activation energy for V\({}_{\text{max},25}\) & 65,000 & J mol\({}^{-1}\) \\ \hline E\({}_{\text{TI}}\) & Activation energy for maximum electron transport rate & 35,000 & J mol\({}^{-1}\) \\ \hline J\({}_{\text{max}25}\)(25 \({}^{\circ}\)C) & Maximum summer electron transport rate at 25 \({}^{\circ}\)C & 36.5 & umel e\({}^{-}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline J\({}_{\text{max}25P}\)(25 \({}^{\circ}\)C) & Maximum spring electron transport rate at 25 \({}^{\circ}\)C & 17.5 & umel e\({}^{-}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline J\({}_{\text{max}25P}\)(25 \({}^{\circ}\)C) & Maximum fall electron transport rate at 25 \({}^{\circ}\)C & 18.5 & umel e\({}^{-}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline K\({}_{\text{C}25}\)(25 \({}^{\circ}\)C) & Michaelis-Menten constant for Rubisco CO\({}_{2}\) fixation & 275 & umol mol\({}^{-1}\) \\ \hline K\({}_{\text{O}25}\) (25 \({}^{\circ}\)C) & Michaelis-Menten constant for Rubisco O\({}_{2}\) utilization & 420,000 & umol mol\({}^{-1}\) \\ \hline R\({}_{\text{A,light,25}}\) & Mitochondrial respiration in the light at 25 \({}^{\circ}\)C & 1.3 & umol CO\({}_{2}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline S\({}_{\text{CO}}\) (25 \({}^{\circ}\)C) & Relative CO\({}_{2}\)/O\({}_{2}\) specificity factor for Rubisco & 2800 & bar bar\({}^{-1}\) \\ \hline S\({}_{\text{TI}}\) & Entropy with deactivation & 650 & J K\({}^{-1}\) mol\({}^{-1}\) \\ \hline V\({}_{\text{max}25S}\)(25 \({}^{\circ}\)C) & Maximum rate of carboxylation in summer at 25 \({}^{\circ}\)C & 19.5 & umel e\({}^{-}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline V\({}_{\text{max}25P}\)(25 \({}^{\circ}\)C) & Maximum rate of carboxylation in spring at 25 \({}^{\circ}\)C & 7.5 & umel e\({}^{-}\) m\({}^{-2}\) s\({}^{-1}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Selected parameters of _DIMONA_ PB model for photosynthesis, plant productivity, growth, and nutrient uptake. Model runs for hummocks and hollows driven by observed \(\mathrm{d}_{\mathrm{WT}}\) or near-surface \(\theta\) with various combinations of equations for soil water retention curves (SWRCs) and stomatal conductance chosen via _DIMONA_ GUI (Figure 2b) to represent the soil water constraints (via simulated \(\overline{\theta}\) and \(\theta_{1}\)) and atmospheric water constraints (via simulated \(\mathrm{g}_{\mathrm{s}}\)) were conducted to show that the modifiers \(\mathrm{f}_{\mathrm{P}}\), \(\mathrm{f}_{\mathrm{Q}}\), \(\mathrm{f}_{\mathrm{R}}\), and \(\mathrm{f}_{\mathrm{U}\mathrm{i}}\) work reasonably well, i.e., to test Hypotheses 1 and 2. Hummock \(\mathrm{d}_{\mathrm{WT}}\) was elevated by 25 cm to run for hollows. All model runs are summarized in Table 2 along with their model names, hydrological drivers (\(\mathrm{d}_{\mathrm{WT}}\) or near-surface \(\theta\)), SWRCs (Van Genuchten or Campbell), and stomatal conductance equations (Ball-Berry or Leuning). each model run, hummock and hollow GPP and NPP were obtained by summing hummock and hollow shrub and moss GPP and NPP. Ecosystem GPP and NPP were obtained by summing the hummock and hollow values, weighted, respectively, at 0.67 and 0.33 to reflect the microform surface coverage. Simulated ecosystem GPP was compared to observed eddy covariance (EC)-derived ecosystem GPP. Comparisons were made at hourly and at daily time steps, the latter to eliminate the effects of possible autocorrelation due to the diurnal pattern of hourly photosynthesis. Hourly-binned aggregations were analyzed too to show the general patterns.