R/C4EstimateWithCA.R

Defines functions C4EstimateWithCA

Documented in C4EstimateWithCA

#' Estimate photosynthesis parameters for C4 species using Sharkey's fitting procedure
#'
#' Using the gas exchange measurement (A_Ci curve), C4 photosynthesis model with
#' carbonic anhydrase reaction and Sharkey et al. (2007) fitting processure to do
#' nonlinear curve fitting (using nlminb package) for estimating photosynthesis
#' parameters (Vcmax,J,Rd,gm and Vpmax) for C4 species. Make sure to load the "stats"
#' package before intstalling and using the "C4Estimation" package.
#' @param ACi     Gas exchange measurement from Li6400 or other equipment. It is a
#' dataframe iput. Ci with the unit of ppm. You can prepare the data in Excel file
#' like the given example and save it as "tab delimited text". Then import data by
#' ACi <- read.table(file = "/Users/haoranzhou/Desktop/Learn R/ACi curve.txt",
#' header = TRUE)
#' @param Tleaf   Leaf temperature when A_Ci curve is measured.
#' @param Patm    Atmosphere pressure when A_Ci curve is measured.
#' @param alpha1  The fraction of O2 evolution occurring in the bundle sheath.
#' Unless you have enough information, input it as the 0.15.
#' @param x       the fraction of total electron transport that are confined to be
#' used for the PEP regeneration out of J, which is the total electron transport.
#' @param CaBreakL  Higher bound of Ci below which A is thought to be controled by
#' Rubisco Carboxylation (Ac). Start with 10.
#' @param CaBreakH  Lower bound of Ci above which A is thought to be controled by
#' RuBP regeneration (Aj). Start with 50. If the estimation results showed
#' "inadmissible fits", change the CaBreakL and CaBreakH until "inadmissible fits"
#' disappear.
#' @param startp    A vector that gives the start points for the estimation
#' (c(Vcmax,J,Rd,gm,Vpmax,KCA))
#' @return This package will return a dataframe that contains the following values
#' (c(Vcmax,J,Rd,gm,Vpmax and KCA)). You can try with c(30, 150, 3, 10, 50, 80).
#' @return Parameter at leaf temperature:      A vector (c(Vcmax,J,Rd,gm,Vpmax and
#' KCA)) returns the estimation parameters at leaf temperature.
#' @return Parameter at 25°C:                  A vector (c(Vcmax,J,Rd,gm,Vpmax and
#' KCA)) returns the estimation parameters at leaf temperature.
#' @return Objective:                          The final objective value based on
#' the estimation results.
#' @return Convergence:                        An integer code. 0 indicates
#' successful convergence.
#' @return Message:	                          A character string giving any
#' additional information returned by the optimizer, or NULL. For details, see PORT
#' documentation.
#' @return Iterations:	                        Number of iterations performed.
#' @return Evaluations:	                      Number of objective function and
#' gradient function evaluations.
#' @export

C4EstimateWithCA<- function(ACi,Tleaf,Patm,alpha1,x,CaBreakL,CaBreakH,startp)
  {

  A.obs <- ACi$A
  Ci.obs<-ACi$Ci*Patm*0.001
  O2<-Patm*0.21

  #Temperature adjustment for Kc,Ko,gammastar,Kp from 25°C to Tleaf
  Kc<-75.06*exp(36.5*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  Ko<-35.82*exp(12.8*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  gammastar<-0.000244*exp(24.82*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  Kp <- 8.5455*exp(52.2*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  Kp2 <- 33.541088*exp(27.20*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  gbs <-0.029455*exp(116.77*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))*
        (1+exp((298.15*0.86-264.6)/298.15/0.008314))/
        (1+exp(((273.15+Tleaf)*0.86-264.6)/(273.15+Tleaf)/0.008314))
  kr<-0.00332955*exp(65.2704*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  kf<-0.0389858*exp(74.8936*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))
  KH<-2.9799*exp(-2400*(1/(273.15+Tleaf)-1/298.15))
  #Define objective function
  fn2<-function(Param){
    Vcmax <- Param[1]
    J <- Param[2]
    Rd <- Param[3]
    gm <- Param[4]
    Vpmax <- Param[5]
    KCA <- Param[6]
    Rm <- Rd/2

    #Useful intermediates
    Obs <- alpha1*(A.obs+Rd)/(0.047*gbs)/1000+O2
    cm <- Ci.obs-A.obs/gm
    a_hco3 <- KCA*KH*kr/kf
    b_hco3 <- Vpmax-cm*KCA+Kp2*KCA*KH*kr/kf
    c_hco3 <- -cm*KCA*Kp2
    hco3 <- (-b_hco3+(b_hco3*b_hco3-4*a_hco3*c_hco3)^0.5)/2/a_hco3
    Vpc1 <- Vpmax*(gm*Ci.obs-A.obs)/(gm*Ci.obs-A.obs+Kp*gm)
    Vpc2 <-Vpmax*hco3/(hco3+Kp2)
    Vpr <- x*J/2
    Cbspc1 <- Vpmax*(gm*Ci.obs-A.obs)/(gm*Ci.obs-A.obs+Kp*gm)/gbs-
              Rd/2/gbs-A.obs/gbs+Ci.obs-A.obs/gm
    Cbspc2 <- (Vpc2-A.obs-Rd/2)/gbs+cm
    Cbspr <- x*J/2/gbs-Rd/2/gbs-A.obs/gbs+Ci.obs-A.obs/gm
    Acpc1 <- Vcmax*(Cbspc1-gammastar*Obs*1000)/(Cbspc1+Kc*(1+Obs/Ko))
    Acpc2 <- Vcmax*(Cbspc2-gammastar*Obs*1000)/(Cbspc2+Kc*(1+Obs/Ko))
    Acpr <- Vcmax*(Cbspr-gammastar*Obs*1000)/(Cbspr+Kc*(1+Obs/Ko))
    Ajpc1 <- (1-x)*J*(Cbspc1-gammastar*Obs*1000)/(4*Cbspc1+8*gammastar*Obs*1000)
    Ajpc2 <- (1-x)*J*(Cbspc2-gammastar*Obs*1000)/(4*Cbspc2+8*gammastar*Obs*1000)
    Ajpr <- (1-x)*J*(Cbspr-gammastar*Obs*1000)/(4*Cbspr+8*gammastar*Obs*1000)

    #Objective
    sum(((Ci.obs<=CaBreakL)*((Vpc1<=Vpc2)*(Acpc1)+(Vpc1>Vpc2)*Acpc2-Rd)+
        (Ci.obs>CaBreakL)*(Ci.obs<CaBreakH)*
        ((Vpc1<Vpc2)*((Vpc1<Vpr)*((Acpc1<Ajpc1)*Acpc1+(Acpc1>=Ajpc1)*Ajpc1)+
                       (Vpc1>=Vpr)*((Acpr<Ajpr)*Acpr+(Acpr>=Ajpr)*Ajpr))+
          (Vpc1>=Vpc2)*((Vpc2<Vpr)*((Acpc2<Ajpc2)*Acpc2+(Acpc2>=Ajpc2)*Ajpc2)+
                         (Vpc2>=Vpr)*((Acpr<Ajpr)*Acpr+(Acpr>=Ajpr)*Ajpr))-Rd)+
        (Ci.obs>=CaBreakH)*(Ajpr-Rd)-A.obs)^2)
  }

  #Using constrained optimization package "nloptr" to estimate Vcmax,J,Rd,gm and Vpmax
  Est.model <- nlminb(c(startp[1],startp[2],startp[3],startp[4],startp[5],startp[6]),
                      fn2, lower=c(0,0,0,0,0,0), upper=c(200, 600, 20, 30, 200,200))
  Parameters<-Est.model$par
  Vcmax <- Parameters[1]
  J <- Parameters[2]
  Rd <- Parameters[3]
  gm <- Parameters[4]
  Vpmax <- Parameters[5]
  KCA <- Parameters[6]
  Rm <- Rd/2

  #Temperature adjustment for Vcmax,J,Rd,gm and Vpmax from Tleaf to 25°C
  Vcmax25<-Parameters[1]/(exp(51.89*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf))))
  J25<-Parameters[2]/(exp(69.246*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))*
                      (1+exp((298.15*0.609-188.502)/298.15/0.008314))/
                      (1+exp(((273.15+Tleaf)*0.609-188.502)/(273.15+Tleaf)/0.008314)))
  Rd25<-Parameters[3]/(exp(41.85*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf))))
  gm25<-Parameters[4]/(exp(46.533*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))*
                       (1+exp((298.15*1.2-366.8)/298.15/0.008314))/
                       (1+exp(((273.15+Tleaf)*1.2-366.8)/(273.15+Tleaf)/0.008314)))
  Vpmax25<-Parameters[5]/(exp(65.6905*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf)))*
                          (1+exp((298.15*0.47-147.69375)/298.15/0.008314))/
                          (1+exp(((273.15+Tleaf)*0.47-147.69375)/(273.15+Tleaf)/
                                  0.008314)))
  KCA25<-Parameters[6]/(exp(40.9*(Tleaf-25)/(298.15*0.008314*(273.15+Tleaf))))

  para25<-c(Vcmax25,J25,Rd25,gm25,Vpmax25,KCA25)
  #Calculate the estimation results

  #Useful intermediate
  O2<-Patm*0.21*1000
  x1_ac <- Vcmax
  x2_ac <- Kc/Ko/1000
  x3_ac <- Kc
  deno_ac <- gm+gbs-x2_ac*gm*alpha1/0.047

  x1_aj <- (1-x)*J/4
  x2_aj <- 2*gammastar
  x3_aj <- 0
  deno_aj <- gm+gbs-x2_aj*gm*alpha1/0.047

  #Explicit calculation of AEE and AET
  d <- gm*(Rm-Vpmax-Ci.obs*(gm+2*gbs)-Kp*(gm + gbs))
  f <- gm*gm*(Ci.obs*Vpmax+(Ci.obs+Kp)*(gbs*Ci.obs-Rm))
  k <- gm*gm*gbs*(Ci.obs+Kp)

  RcPc_p <- (d-(x3_ac+x2_ac*O2)*gm*gbs+(Rd-x1_ac)*(gm+gbs)-
            (x1_ac*gammastar*gm+x2_ac*Rd*gm-x2_ac*k/gbs)*alpha1/0.047)/deno_ac
  RrPc_p <- (d-(x3_aj+x2_aj*O2)*gm*gbs+(Rd-x1_aj)*(gm+gbs)-
            (x1_aj*gammastar*gm+x2_aj*Rd*gm-x2_aj*k/gbs)*alpha1/0.047)/deno_aj
  RcPc_q <- (f+(x3_ac+x2_ac*O2)*k+d*(Rd-x1_ac)-
            gm*gbs*(x1_ac*gammastar*O2+Rd*(x3_ac+x2_ac*O2))+
            (x1_ac*gammastar+x2_ac*Rd)*k*alpha1/0.047/gbs)/deno_ac
  RrPc_q <- (f+(x3_aj+x2_aj*O2)*k+d*(Rd-x1_aj)-
            gm*gbs*(x1_aj*gammastar*O2+Rd*(x3_aj+x2_aj*O2))+
            (x1_aj*gammastar+x2_aj*Rd)*k*alpha1/0.047/gbs)/deno_aj
  RcPc_r <- (Rd*(f+(x3_ac+x2_ac*O2)*k)-x1_ac*(f-k*gammastar*O2))/deno_ac
  RrPc_r <- (Rd*(f+(x3_aj+x2_aj*O2)*k)-x1_aj*(f-k*gammastar*O2))/deno_aj

  RcPc_Q <- (RcPc_p*RcPc_p-3*RcPc_q)/9
  RrPc_Q <- (RrPc_p*RrPc_p-3*RrPc_q)/9
  RcPc_U <- (2*RcPc_p^3-9*RcPc_p*RcPc_q+27*RcPc_r)/54
  RrPc_U <- (2*RrPc_p^3-9*RrPc_p*RrPc_q+27*RrPc_r)/54
  RcPc_PHI <- acos(RcPc_U/(RcPc_Q^3)^0.5)
  RrPc_PHI <- acos(RrPc_U/(RrPc_Q^3)^0.5)

  RcPc <- -2*RcPc_Q^0.5*cos(RcPc_PHI/3)-RcPc_p/3
  RrPc <- -2*RrPc_Q^0.5*cos(RrPc_PHI/3)-RrPc_p/3


  ##Explicit calculation of ATE and ATT
  Vpr <- x*J/2

  a_ac <- x2_ac*gm*alpha1/0.047-gm-gbs
  a_aj <- x2_aj*gm*alpha1/0.047-gm-gbs
  b_ac <- gm*(Ci.obs*gbs+Vpr-Rm)+(x3_ac+x2_ac*O2)*gm*gbs+
          (x1_ac*gammastar+x2_ac*Rd)*gm*alpha1/0.047+(gm+gbs)*(x1_ac-Rd)
  b_aj <- gm*(Ci.obs*gbs+Vpr-Rm)+(x3_aj+x2_aj*O2)*gm*gbs+
          (x1_aj*gammastar+x2_aj*Rd)*gm*alpha1/0.047+(gm+gbs)*(x1_aj-Rd)
  c_ac <- -gm*(Ci.obs*gbs+Vpr-Rm)*(x1_ac-Rd)+
          gm*gbs*(x1_ac*gammastar*O2+Rd*(x3_ac+x2_ac*O2))
  c_aj <- -gm*(Ci.obs*gbs+Vpr-Rm)*(x1_aj-Rd)+
          gm*gbs*(x1_aj*gammastar*O2+Rd*(x3_aj+x2_aj*O2))

  RcPr <- (-b_ac+(b_ac^2-4*a_ac*c_ac)^0.5)/2/a_ac
  RrPr <- (-b_aj+(b_aj^2-4*a_aj*c_aj)^0.5)/2/a_aj

  Vpc_RcPc <- Vpmax*(Ci.obs-RcPc/gm)/((Ci.obs-RcPc/gm)+Kp)
  Vpc_RrPc <- Vpmax*(Ci.obs-RrPc/gm)/((Ci.obs-RrPc/gm)+Kp)

  Ac <- (Vpc_RcPc<=Vpr)*RcPc+(Vpc_RcPc>Vpr)*RcPr
  Aj <- (Vpc_RrPc<=Vpr)*RrPc+(Vpc_RrPc>Vpr)*RrPr

  #Calculate the real estimation error term

  Error1 <- sum((A.obs-(Ac<=Aj)*Ac-(Ac>Aj)*Aj)^2)

  #Write a while loop to compare Ac and Aj
  Count<-length(Ci.obs)
  limitation <- rep(0,Count)
  i <- 1
  while (i<=Count){
    limitation[i] <- 2*(Ac[i]>=Aj[i])+1*(Ac[i]<Aj[i])
    i=i+1
}
  #Print out to see whether there is inadmissible fit
  print("Print out to see whether there is inadmissible fit")
  Ci_name <- "Ci"
  limitation_name <- "limitation_state"
  df <- data.frame(Ci.obs,limitation)
  colnames(df)<-c(Ci_name,limitation_name)
  print(df)

  #Plot the estimation and observation
  print("Plot the observed A and estimated Ac and Aj")
  xrange<-max(Ci.obs)
  yrange<-max(RcPc)
  plot(Ci.obs,A.obs, type="p",col="blue",xlim=range(0,xrange),ylim=range(0,yrange),
       pch=20, xlab="Ci(Pa)",ylab="A")
  lines(Ci.obs,RcPc, type="l",col="red4",lwd=2)
  lines(Ci.obs,RcPr,type="l",col="red",lwd=2)
  lines(Ci.obs,RrPc, type="l",col="green",lwd=2)
  lines(Ci.obs,RrPr,type="l",col="green4",lwd=2)
  leg.text<-c("Obs A", "Cal RcPc", "Cal RcPr","Cal RrPc","Cal RrPr")
  xrange<-max(Ci.obs)
  legend(xrange-20,7,leg.text,col=c("blue","red4","red","green","green4"),
         pch=c(20,NA,NA,NA,NA),lty=c(0,1,1,1,1),cex=0.5,lwd=c(0,2,2,2,2))

  #Return the estimation results
  EstF<-list(Est.model$par,para25,Est.model$objective,Error1,Est.model$convergence,
             Est.model$iterations,Est.model$evaluations,Est.model$message)
  EstFinal<-setNames(EstF,c("Parameter at leaf temperature","Parameter at 25°C",
                            "Objective","Estimation Error","Convergence","Iterations",
                            "Evaluations","Message"))
  return(EstFinal)
}
zhouhaoran06/C4-Parameter-Estimation documentation built on Dec. 23, 2021, 9:20 p.m.