General Overview


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This report is the result of the use of the python package bgc_md, as means to translate published models to a common language. The underlying yaml file was created by Verónika Ceballos-Núñez (Orcid ID: 0000-0002-0046-1160) on .

About the model

The model depicted in this document considers carbon allocation with a process based approach. It was originally described by Gu et al. (2010).

Space Scale

forest

state_variables
Name Description Unit
\(C_{S}\) Carbon in stem -
\(C_{R}\) Carbon in root -
\(C_{L}\) Carbon in leaf -
photosynthetic_parameters
Name Description Unit
\(t\) time step \(year\)
\(NPP\) Net Primary Production -
\(L\) Scalar light availability -
\(W\) Scalar water availability -
nutrient_uptake
Name Description Expression
\(N_{ava}\) effect of nitrogen availability on carbon allocation -
partitioning_rates
Name Description Expression
\(\Omega\) Sensitivity of allocation to changes in resources availability. If =0, partitioning is determined by constant allocation fractions. -
\(\epsilon_{S}\) Parameter relative to vegetation type -
\(\epsilon_{R}\) Parameter relative to vegetation type -
\(\epsilon_{L}\) Parameter relative to vegetation type \(\epsilon_{L}=-\epsilon_{R} -\epsilon_{S} + 1\)
\(a_{S}\) Allocation fraction to stem \(a_{S}=\frac{\Omega\cdot\left(- L - 0.5\cdot N_{ava} + 1.5\right) +\epsilon_{S}}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)
\(a_{R}\) Allocation fraction to root \(a_{R}=\frac{\Omega\cdot\left(- 0.5\cdot N_{ava} - W + 1.5\right) +\epsilon_{R}}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)
\(a_{L}\) Allocation fraction to leaf \(a_{L}=\frac{\epsilon_{L}}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)
cycling_rates
Name Description Unit
\(\gamma_{S}\) Stem turnover rate \(years\)
\(\gamma_{R}\) Root turnover rate \(years\)
\(\gamma_{L}\) Stem turnover rate \(years\)
components
Name Description Expression
\(x\) vector of states for vegetation \(x=\left[\begin{matrix}C_{S}\\C_{R}\\C_{L}\end{matrix}\right]\)
\(u\) scalar function of photosynthetic inputs \(u=NPP\)
\(b\) vector of partitioning coefficients of photosynthetically fixed carbon \(b=\left[\begin{matrix}a_{S}\\a_{R}\\a_{L}\end{matrix}\right]\)
\(A\) matrix of cycling rates \(A=\left[\begin{matrix}-\gamma_{S} & 0 & 0\\0 & -\gamma_{R} & 0\\0 & 0 & -\gamma_{L}\end{matrix}\right]\)
\(f_{v}\) the righthandside of the ode \(f_{v}=u b + A x\)

Pool model representation


Figure 1
Figure 1: Pool model representation

Input fluxes

\(C_{S}: \frac{NPP\cdot\left(\Omega\cdot\left(- L - 0.5\cdot N_{ava} + 1.5\right) +\epsilon_{S}\right)}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)
\(C_{R}: \frac{NPP\cdot\left(\Omega\cdot\left(- 0.5\cdot N_{ava} - W + 1.5\right) +\epsilon_{R}\right)}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)
\(C_{L}: \frac{NPP\cdot\left(-\epsilon_{R} -\epsilon_{S} + 1\right)}{\Omega\cdot\left(- L - N_{ava} - W + 3\right) + 1}\)

Output fluxes

\(C_{S}: C_{S}\cdot\gamma_{S}\)
\(C_{R}: C_{R}\cdot\gamma_{R}\)
\(C_{L}: C_{L}\cdot\gamma_{L}\)

Steady state formulas

\(C_S = \frac{0.5\cdot NPP\cdot\left(2.0\cdot L\cdot\Omega + N_{ava}\cdot\Omega - 3.0\cdot\Omega - 2.0\cdot\epsilon_{S}\right)}{\gamma_{S}\cdot\left(L\cdot\Omega + N_{ava}\cdot\Omega +\Omega\cdot W - 3.0\cdot\Omega - 1.0\right)}\)

\(C_R = \frac{0.5\cdot NPP\cdot\left(N_{ava}\cdot\Omega + 2.0\cdot\Omega\cdot W - 3.0\cdot\Omega - 2.0\cdot\epsilon_{R}\right)}{\gamma_{R}\cdot\left(L\cdot\Omega + N_{ava}\cdot\Omega +\Omega\cdot W - 3.0\cdot\Omega - 1.0\right)}\)

\(C_L = \frac{NPP\cdot\left(\epsilon_{R} +\epsilon_{S} - 1.0\right)}{\gamma_{L}\cdot\left(L\cdot\Omega + N_{ava}\cdot\Omega +\Omega\cdot W - 3.0\cdot\Omega - 1.0\right)}\)

References

Gu, F., Zhang, Y., Tao, B., Wang, Q., Yu, G., Zhang, L., & Li, K. (2010). Modeling the effects of nitrogen deposition on carbon budget in two temperate forests. Ecological Complexity, 7(2), 139–148. http://doi.org/10.1016/j.ecocom.2010.04.002