| TwopFeedbackModel {SoilR} | R Documentation |
This function creates a model for two pools connected with feedback. It is a
wrapper for the more general function GeneralModel.
TwopFeedbackModel( t, ks, a21, a12, C0, In, xi = 1, solver = deSolve.lsoda.wrapper, pass = FALSE )
t |
A vector containing the points in time where the solution is sought. |
ks |
A vector of length 2 with the values of the decomposition rate for pools 1 and 2. |
a21 |
A scalar with the value of the transfer rate from pool 1 to pool 2. |
a12 |
A scalar with the value of the transfer rate from pool 2 to pool 1. |
C0 |
A vector of length 2 containing the initial amount of carbon for the 2 pools. |
In |
A data.frame object specifying the amount of litter inputs by time. |
xi |
A scalar or data.frame object specifying the external (environmental and/or edaphic) effects on decomposition rates. |
solver |
A function that solves the system of ODEs. This can be
|
pass |
if TRUE forces the constructor to create the model even if it is invalid |
A Model Object that can be further queried
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.
There are other predefinedModels and also more
general functions like Model.
#This example show the difference between the three types of two-pool models
times=seq(0,20,by=0.1)
ks=c(k1=0.8,k2=0.00605)
C0=c(C10=5,C20=5)
Temp=rnorm(times,15,2)
WC=runif(times,10,20)
TempEffect=data.frame(times,fT=fT.Daycent1(Temp))
MoistEffect=data.frame(times, fW=fW.Daycent2(WC)[2])
Inmean=1
InRand=data.frame(times,Random.inputs=rnorm(length(times),Inmean,0.2))
InSin=data.frame(times,Inmean+0.5*sin(times*pi*2))
Parallel=TwopParallelModel(t=times,ks=ks,C0=C0,In=Inmean,gam=0.9,
xi=(fT.Daycent1(15)*fW.Demeter(15)))
Series=TwopSeriesModel(t=times,ks=ks,a21=0.2*ks[1],C0=C0,In=InSin,
xi=(fT.Daycent1(15)*fW.Demeter(15)))
Feedback=TwopFeedbackModel(t=times,ks=ks,a21=0.2*ks[1],a12=0.5*ks[2],C0=C0,
In=InRand,xi=MoistEffect)
CtP=getC(Parallel)
CtS=getC(Series)
CtF=getC(Feedback)
RtP=getReleaseFlux(Parallel)
RtS=getReleaseFlux(Series)
RtF=getReleaseFlux(Feedback)
par(mfrow=c(2,1),mar=c(4,4,1,1))
plot(times,rowSums(CtP),type="l",ylim=c(0,20),ylab="Carbon stocks (arbitrary units)",xlab=" ")
lines(times,rowSums(CtS),col=2)
lines(times,rowSums(CtF),col=3)
legend("topleft",c("Two-pool Parallel","Two-pool Series","Two-pool Feedback"),
lty=c(1,1,1),col=c(1,2,3),bty="n")
plot(times,rowSums(RtP),type="l",ylim=c(0,3),ylab="Carbon release (arbitrary units)", xlab="Time")
lines(times,rowSums(RtS),col=2)
lines(times,rowSums(RtF),col=3)
par(mfrow=c(1,1))