SoilR (version 1.2.107)

ThreepParallelModel14: Implementation of a three-pool C14 model with parallel structure

Description

This function creates a model for two independent (parallel) pools. It is a wrapper for the more general function GeneralModel_14 that can handle an arbitrary number of pools.

Usage

ThreepParallelModel14(
  t,
  ks,
  C0,
  F0_Delta14C,
  In,
  gam1,
  gam2,
  xi = 1,
  inputFc,
  lambda = -0.0001209681,
  lag = 0,
  solver = deSolve.lsoda.wrapper,
  pass = FALSE
)

Arguments

t

A vector containing the points in time where the solution is sought. It must be specified within the same period for which the Delta 14 C of the atmosphere is provided. The default period in the provided dataset C14Atm_NH is 1900-2010.

ks

A vector of length 3 containing the decomposition rates for the 3 pools.

C0

A vector of length 3 containing the initial amount of carbon for the 3 pools.

F0_Delta14C

A vector of length 3 containing the initial amount of the radiocarbon fraction for the 3 pools in Delta14C values in per mil.

In

A scalar or a data.frame object specifying the amount of litter inputs by time.

gam1

A scalar representing the partitioning coefficient, i.e. the proportion from the total amount of inputs that goes to pool 1.

gam2

A scalar representing the partitioning coefficient, i.e. the proportion from the total amount of inputs that goes to pool 2.

xi

A scalar or a data.frame specifying the external (environmental and/or edaphic) effects on decomposition rates.

inputFc

A Data Frame object containing values of atmospheric Delta14C per time. First column must be time values, second column must be Delta14C values in per mil.

lambda

Radioactive decay constant. By default lambda=-0.0001209681 y^-1 . This has the side effect that all your time related data are treated as if the time unit was year.

lag

A positive scalar representing a time lag for radiocarbon to enter the system.

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

if TRUE Forces the constructor to create the model even if it is invalid

See Also

There are other predefinedModels and also more general functions like Model_14.

Examples

years=seq(1903,2009,by=0.5) # note that we 
LitterInput=700 

Ex=ThreepParallelModel14(
t=years,
ks=c(k1=1/2.8, k2=1/35, k3=1/100),
C0=c(200,5000,500),
F0_Delta14C=c(0,0,0),
In=LitterInput,
gam1=0.7,
gam2=0.1,
inputFc=C14Atm_NH,
lag=2
)
R14m=getF14R(Ex)
C14m=getF14C(Ex)
C14t=getF14(Ex)

par(mfrow=c(2,1))
plot(C14Atm_NH,type="l",xlab="Year",ylab="Delta 14C (per mil)",xlim=c(1940,2010)) 
lines(years, C14t[,1], col=4)
lines(years, C14t[,2],col=4,lwd=2)
lines(years, C14t[,3],col=4,lwd=3)
legend(
"topright",
c(
"Delta 14C Atmosphere", 
"Delta 14C pool 1",
"Delta 14C pool 2", 
"Delta 14C pool 3"
),
lty=rep(1,4),
col=c(1,4,4,4),
lwd=c(1,1,2,3),
bty="n"
)

plot(C14Atm_NH,type="l",xlab="Year",ylab="Delta 14C (per mil)",xlim=c(1940,2010)) 
lines(years,C14m,col=4)
lines(years,R14m,col=2)
legend("topright",c("Delta 14C Atmosphere","Delta 14C SOM", "Delta 14C Respired"),
lty=c(1,1,1), col=c(1,4,2),bty="n")
par(mfrow=c(1,1))