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 16/9/2016.

About the model

The model depicted in this document considers carbon allocation with a process based approach. It was originally described by Williams, Schwarz, Law, Irvine, & Kurpius (2005).

Keywords

Deciduous forest, Phenology

Principles

All C fixed during a day is either released -autotrophic respiration (Ra)- or allocated to tissue pools (C_f, C_w, C_r), R_a is not directly temperature sensitive, Phenology -> Timing of leaf out controlled by simple growing degree day model, and leaf-fall by a min. temperature threshold., Maximum amount of C that can be allocated to leaves is limited by the parameter C_fmax, All C losses are via mineralization (no dissolved losses)

Space Scale

deciduous forest

Available parameter values

Information on given parameter sets
Abbreviation Description Source
param_vals NPP value was given per year. p14, p15 and p16 values not given in publication Williams et al. (2005)

Available initial values

Information on given sets of initial values
Abbreviation Description Source
init_vals C_lab values not provided in publication Williams et al. (2005)
state_variables
Name Description Unit
\(C_{f}\) Foliar C mass \(gC\cdot m^{-2}\)
\(C_{lab}\) Labile C mass \(gC\cdot m^{-2}\)
\(C_{w}\) Wood C mass \(gC\cdot m^{-2}\)
\(C_{r}\) Fine root C mass \(gC\cdot m^{-2}\)
photosynthetic_parameters
Name Description Unit
\(NPP\) \(gC\cdot m^{-2}\cdot day^{-1}\)
respiration_parameters
Name Description Unit
\(p_{2}\) Fraction of GPP respired -
\(p_{16}\) Fraction of labile transfers respired \(day^{-1}\)
partitioning_coefficients
Name Description
\(p_{3}\) Fraction of NPP partitioned to foliage
\(p_{4}\) Fraction of NPP partitioned to roots
cycling_rates
Name Description Unit
\(p_{5}\) Turnover rate of foliage \(day^{-1}\)
\(p_{6}\) Turnover rate of wood \(day^{-1}\)
\(p_{7}\) Turnover rate of roots \(day^{-1}\)
\(p_{14}\) Fraction of leaf loss transferred to litter -
\(p_{15}\) Turnover rate of labile carbon \(day^{-1}\)
phenology_parameters
Name Description Expression Unit
\(t\) time - \(day\)
\(p_{10}\) Parameter in exponential term of temperature dependent rate parameter - -
\(mint\) Dayly minimum temperature - -
\(maxt\) Dayly maximum temperature - -
\(T_{rate}\) Temperature sensitive rate parameter \(T_{rate}=0.5\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\) -
\(multtl\) Turnover of labile C (0 = off, 1 = On) - -
\(multtf\) Turnover of foliage C (0 = off, 1 = On) - -
components
Name Description Expression
\(x\) vector of states of vegetation \(x=\left[\begin{matrix}C_{f}\\C_{lab}\\C_{w}\\C_{r}\end{matrix}\right]\)
\(u\) scalar function of photosynthetic inputs \(u=NPP\)
\(b\) vector of partitioning coefficients of photosynthetically fixed carbon \(b=\left[\begin{matrix}multtl\cdot p_{3}\\0\\1 - p_{4}\\p_{4}\end{matrix}\right]\)
\(A\) matrix of cycling rates \(A=\left[\begin{matrix}- T_{rate}\cdot multtf\cdot p_{16}\cdot p_{5}\cdot\left(1 - p_{14}\right) - T_{rate}\cdot multtf\cdot p_{5}\cdot\left(1 - p_{14}\right)\cdot\left(1 - p_{16}\right) - multtf\cdot p_{14}\cdot p_{5} & T_{rate}\cdot multtl\cdot p_{15}\cdot\left(1 - p_{16}\right) & 0 & 0\\T_{rate}\cdot multtf\cdot p_{5}\cdot\left(1 - p_{14}\right)\cdot\left(1 - p_{16}\right) & - T_{rate}\cdot multtl\cdot p_{15}\cdot p_{16} - T_{rate}\cdot multtl\cdot p_{15}\cdot\left(1 - p_{16}\right) & 0 & 0\\0 & 0 & - p_{6} & 0\\0 & 0 & 0 & - p_{7}\end{matrix}\right]\)
\(f_{v}\) the right hand side of the ode \(f_{v}=u b + A x\)

Pool model representation


Figure 1
Figure 1: Pool model representation

Input fluxes

\(C_{f}: NPP\cdot multtl\cdot p_{3}\)
\(C_{w}: NPP\cdot\left(1 - p_{4}\right)\)
\(C_{r}: NPP\cdot p_{4}\)

Output fluxes

\(C_{f}: C_{f}\cdot multtf\cdot p_{5}\cdot\left(p_{14} - 0.5\cdot p_{16}\cdot\left(p_{14} - 1\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\right)\)
\(C_{lab}: 0.5\cdot C_{lab}\cdot multtl\cdot p_{15}\cdot p_{16}\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\)
\(C_{w}: C_{w}\cdot p_{6}\)
\(C_{r}: C_{r}\cdot p_{7}\)

Internal fluxes

\(C_{f} \rightarrow C_{lab}: 0.5\cdot C_{f}\cdot multtf\cdot p_{5}\cdot\left(p_{14} - 1\right)\cdot\left(p_{16} - 1\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\)
\(C_{lab} \rightarrow C_{f}: - 0.5\cdot C_{lab}\cdot multtl\cdot p_{15}\cdot\left(p_{16} - 1\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\)

Steady state formulas

\(C_f = \frac{2.0\cdot NPP\cdot multtl\cdot p_{3}\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}}{multtf\cdot p_{5}\cdot\left(\left(p_{16} - 1.0\right)\cdot\left(p_{14}\cdot p_{16} - p_{14} - p_{16} + 1.0\right)\cdot e^{p_{10}\cdot\left(maxt + mint\right)} +\left(- p_{14}\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)} + 2.0\cdot p_{14} + e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\right)}\)

\(C_lab = \frac{2.0\cdot NPP\cdot p_{3}\cdot\left(p_{14}\cdot p_{16} - p_{14} - p_{16} + 1.0\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}}{p_{15}\cdot\left(\left(p_{16} - 1.0\right)\cdot\left(p_{14}\cdot p_{16} - p_{14} - p_{16} + 1.0\right)\cdot e^{p_{10}\cdot\left(maxt + mint\right)} +\left(- p_{14}\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)} + 2.0\cdot p_{14} + e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\right)\cdot e^{0.5\cdot p_{10}\cdot\left(maxt + mint\right)}\right)}\)

\(C_w = -\frac{NPP\cdot\left(p_{4} - 1.0\right)}{p_{6}}\)

\(C_r = \frac{NPP\cdot p_{4}}{p_{7}}\)

References

Williams, M., Schwarz, P. A., Law, B. E., Irvine, J., & Kurpius, M. R. (2005). An improved analysis of forest carbon dynamics using data assimilation. Global Change Biology, 11(1), 89–105. http://doi.org/10.1111/j.1365-2486.2004.00891.x