TwopParallelModel: Implementation of a linear two pool model with parallel structure

Description

This function creates a model for two independent (parallel) pools. It is a wrapper for the more general function ParallelModel that can handle an arbitrary number of pools.

Usage

TwopParallelModel(
  t,
  ks,
  C0,
  In,
  gam,
  xi = 1,
  solver = deSolve.lsoda.wrapper,
  pass = FALSE
)

Value

A Model Object that can be further queried

Arguments

t: A vector containing the points in time where the solution is sought.
ks: A vector of length 2 containing the decomposition rates for the 2 pools.
C0: A vector of length 2 containing the initial amount of carbon for the 2 pools.
In: A scalar or a data.frame object specifying the amount of litter inputs by time.
gam: A scalar representing the partitioning coefficient, i.e. the proportion from the total amount of inputs that goes to pool 1.
xi: A scalar or a data.frame specifying the external (environmental and/or edaphic) effects on decomposition rates.
solver: A function that solves the system of ODEs. This can be euler or deSolve.lsoda.wrapper or any other user provided function with the same interface.
pass: Forces the constructor to create the model even if it is invalid

References

Sierra, C.A., M. Mueller, S.E. Trumbore. 2012. Models of soil organic matter decomposition: the SoilR package version 1.0. Geoscientific Model Development 5, 1045-1060.

Examples

Run this code

t_start=0 
t_end=10 
tn=50
timestep=(t_end-t_start)/tn 
t=seq(t_start,t_end,timestep) 
Ex=TwopParallelModel(t,ks=c(k1=0.5,k2=0.2),C0=c(c10=100, c20=150),In=10,gam=0.7,xi=0.5)
Ct=getC(Ex)
plot(t,rowSums(Ct),type="l",lwd=2,
ylab="Carbon stocks (arbitrary units)",xlab="Time",ylim=c(0,sum(Ct[1,]))) 
lines(t,Ct[,1],col=2)
lines(t,Ct[,2],col=4)
legend("topright",c("Total C","C in pool 1", "C in pool 2"),
lty=c(1,1,1),col=c(1,2,4),lwd=c(2,1,1),bty="n")

Rt=getReleaseFlux(Ex)
plot(t,rowSums(Rt),type="l",ylab="Carbon released (arbitrary units)",
xlab="Time",lwd=2,ylim=c(0,sum(Rt[1,]))) 
lines(t,Rt[,1],col=2)
lines(t,Rt[,2],col=4) 
legend("topleft",c("Total C release","C release from pool 1", "C release from pool 2"),
lty=c(1,1,1),col=c(1,2,4),lwd=c(2,1,1),bty="n")

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