Lists SIPNET state variables and tunable parameters, mapping symbols to the
model equations, configuration names, units, and I/O fields. See
Model Inputs and
Model Outputs for file formats. Unless noted,
pools are mass per ground area and rates are mass per area per day. The actual parameter set that is used depends on the configured model structure. For equation references, see the model structure documentation.
Rate constant (e.g., for decomposition or respiration)
\(Q_{10}\)
Temperature sensitivity coefficient
\(\alpha\)
Fraction of NPP allocated to a plant pool
\(f\)
Fraction of a pool or flux other than NPP
\(k\)
Scaling factor
\(D\)
Dependency or damping function
\(SLW\)
Specific Leaf Weight (leaf carbon per unit leaf area)
Note on superscripts: Most variables use superscripts and subscripts (e.g., \(F^C_{\text{growth}}\) for growth respiration flux). However, some terms that are widely used in the scientific literature use the common notation \(NPP\), \(GPP\), \(R_H\), \(R_A\), and \(ET\).
Subscripts (Temporal, Spatial, or Contextual Identifiers)¶
Category
Subscript
Description
Temporal identifiers
\(X_0\)
Initial value
\(X_t\)
Value at time \(t\)
\(X_d\)
Daily value or average
\(X_{\text{avg}}\)
Average value (e.g., over a timestep or spatial area)
\(X_{\text{max}}\)
Maximum value (e.g., temperature or rate)
\(X_{\text{min}}\)
Minimum value (e.g., temperature or rate)
\(X_{\text{opt}}\)
Optimal value (e.g., temperature or rate)
Structural components
\(X_{\text{leaf}}\)
Leaf pools or fluxes
\(X_{\text{wood}}\)
Wood pools or fluxes
\(X_{\text{root}}\)
Root pool (general)
\(X_{\text{fine root}}\)
Fine root pool
\(X_{\text{coarse root}}\)
Coarse root pool
\(X_{\text{soil}}\)
Soil pools or processes
\(X_{\text{litter}}\)
Litter pools or processes
\(X_{\text{veg}}\)
Vegetation processes (general)
Processes context
\(X_{\text{resp}}\)
Respiration processes
\(X_{\text{growth}}\)
Growth respiration
\(X_{\text{dec}}\)
Decomposition processes
\(X_{\text{vol}}\)
Volatilization processes
\(X_{\text{drain}}\)
Drainage processes
Chemical / environmental identifiers
\(X_{\text{org}}\)
Organic forms
\(X_{\text{mineral}}\)
Mineral forms
\(X_{\text{anaer}}\)
Anaerobic soil conditions
\(X_{\text{HC}}\)
Water holding capacity
Subscripts may be used in combination, e.g., \(X_{\text{soil,mineral},0}\).
Run-time parameters can change from one run to the next, or when the model is stopped and restarted. These include initial state values and parameters related to plant physiology, soil physics, and biogeochemical cycling.
fraction of plant available soil water which can be removed in one day by transpiration without water stress occurring
unitless
\(D_{\text{frozen,water}}\)
frozenSoilEff
fraction of water that is available if soil is frozen (0 = none available, 1 = all still avail.)
unitless
if frozenSoilEff = 0, then shut down psn. even if WATER_PSN = 0, if soil is frozen (if frozenSoilEff > 0, it has no effect if WATER_PSN = 0)
\(WUE\)
wueConst
water use efficiency constant
unitless
\(WHC_{\text{soil}}\)
soilWHC
soil (transpiration layer) water holding capacity
cm
\(WHC_{\text{leaf}}\)
leafPoolDepth
leaf/canopy evaporative pool capacity per unit leaf area (used to limit interception evaporation when enabled)
cm
Only used when LEAF_WATER = 1 (--leaf-water). defines LAI-scaled cap on interception evaporation: \(immedEvap \le LAI \cdot WHC_{\text{leaf}}\). Excess throughfall goes to the soil.
\(f_{\text{intercept}}\)
immedEvapFrac
fraction of rain that is immediately intercepted & evaporated
unitless
\(f_{\text{fastflow}}\)
fastFlowFrac
fraction of water entering soil that goes directly to drainage
unitless
\(f_a\)
fAnoxia
Soil wetness fraction at which oxygen diffusion begins to limit aerobic respiration
unitless
Used in moisture partitioning between aerobic and anaerobic pathways (\eqref{eq:water_rh_2} in model structure)
\(\eta\)
anaerobicDecompRate
Relative anaerobic decomposition rate
unitless
Active when anaerobic pathway is enabled; expected range \((0,1]\)
\(p\)
anaerobicTransExp
Methane anoxia sensitivity exponent in \(D_{\text{water,CH}_4}=A^p\)
unitless
Expected range \(\ge 1\)
\(K_{\text{CH}_4\text{,soil}}\)
soilMethaneRate
First-order methane production rate constant for the soil C pool
\(\text{day}^{-1}\)
Expected range \(\ge 0\)
\(K_{\text{CH}_4\text{,litter}}\)
litterMethaneRate
First-order methane production rate constant for the litter C pool
\(\text{day}^{-1}\)
Expected range \(\ge 0\)
\(M_{\text{snow}}\)
snowMelt
rate at which snow melts
cm water equivalent per degree Celsius per day
\(r_{d}\)
rdConst
scalar determining amount of aerodynamic resistance