PRELES: A simple semi-empirical ecosystem carbon and water balance...

In ForModLabUHel/Rprebasso: PRELES, YASSO and PREBAS models

A simple semi-empirical ecosystem carbon and water balance model.

Description

The model predicts gross primary production and evapotranpiration (and soil water balance) based on embedded empirical relationships and basic meteorological inputs.

Usage

 
  PRELES(PAR, TAir, VPD, Precip, CO2, fAPAR, 
    GPPmeas = NA, ETmeas = NA, SWmeas = NA, 
      p = rep(NA, 30), DOY = NA, LOGFLAG = 0, control = 0,   
        returncols = c("GPP", "ET", "SW")) 

Arguments

PAR	A numeric vector of daily sums of photosynthetically active radiation, mmol/m2.
TAir	A numeric vector of daily mean temperature, degrees C.
VPD	A numeric vector of daily mean vapour pressure deficits
Precip	A numeric vector of daily rainfall, mm
CO2	A numeric vector of air CO2
fAPAR	A numeric vector of fractions of absorbed PAR by the canopy, 0-1 unitless

## OPTIONAL FOR BYPASSING PREDICTION. FOR DEVELOPMENT ONLY

GPPmeas	NA
ETmeas	NA
SWmeas	NA
p	parameter vector of length 30. If parameter has value NA it is replaced with a default corresponding to Hyytiälä calibration. Vector p has following defaults: SITE AND SOIL RELATED 1 soildepth = 413.0, soildepth 2 Effective field capacity = 0.450, ThetaFC 3 Permanent wilting point = 0.118, ThetaPWP 4 Drainage delay = 3 days, tauDrainage GPP_MODEL_PARAMETERS 5 LUE = 0.748018, betaGPP 6 tauGPP = 13.23383, tauGPP 7 S0GPP = -3.9657867, S0GPP 8 SmaxGPP = 18.76696, SmaxGPP 9 kappaGPP = -0.130473, kappaGPP 10 gammaGPP = 0.034459, gammaGPP 11 soilthresGPP = 0.450828, soilthresGPP 12 bCO2 = 0.5, CO2 modifier in GPP model 13 xCO2 = -0.364, CO2 modifier in ET model EVAPOTRANSPIRATION_PARAMETERS 14 transpiration efficiency = 0.324463, betaET 15 kappaET = 0.874151, kappaET 16 chiET = 0.075601, chiET 17 soilthresET = 0.541605, soilthresET 18 nuET = 0.273584, nu ET ## SNOW_RAIN_PARAMETERS 19 Metlcoeff = 1.2, Meltcoef 20 I_0 = 0.33, I_0 21 CWmax = 4.970496, CWmax, i.e. max canopy water 22 SnowThreshold = 0, SnowThreshold, 23 T_0 = 0, T_0, ## START INITIALISATION PARAMETERS 24 SWinit = 200, SWinit, Initial soil water 25 CWinit = 0, CWinit, Initial Canopy water 26 SOGinit = 0, SOGinit, Initial Snow on Ground 27 Sinit = 20, Sinit, Initial temperature acclimation state 28 t0 = -999, t0 fPheno_start_date_Tsum_accumulation; conif -999, for birch 57 29 tcrit = -999, tcrit, fPheno_start_date_Tsum_Tthreshold, 1.5 birch 30 tsumcrit = -999, tsumcrit, fPheno_budburst_Tsum, 134 birch
DOY	Day of year integer vector. Needed for the prediction of deciduous species phenology. If DOY is not provided and deciduous species phenology parameters are not set to -999, it is assumed that the first values of all input vectors are from 1st Jan, and year has 365 day.
LOGFLAG	levels 0 (default), 1, 2. Generates increasing logging to preles.log file in the run directory.
control	Parameter that selects the transpiration model. Equals etmodel in c-code. if (etmodel == 0) et = D * ET_par.beta*A/pow(D, ET_par.kappa) * pow(fWgpp, ET_par.nu) * // ET differently sensitive to soil water than GPP fCO2mean + // Mean effect of CO2 on transpiration ET_par.chi * s / (s + psychom) * (1-fAPAR) * fWsub * ppfd; if (etmodel == 1) et = D * ET_par.beta*A/pow(D, ET_par.kappa) * pow(fWgpp, ET_par.nu) * fCO2mean + ET_par.chi * (1-fAPAR) * fWsub * ppfd; if (etmodel == 2) et = D * (1 + ET_par.beta/pow(D, ET_par.kappa)) * A / CO2 * pow(fWgpp, ET_par.nu) * fCO2mean + ET_par.chi * (1-fAPAR) * fWsub * ppfd;
returncols	What columns are returned, defaults to c('GPP','ET','SW'). Other possible options are fD for vapour pressure deficit modifier, fW for soil water modifier, fE (minimum of fD, fW), fS (temperature/season modifier), SOG (snow on ground, mm weq.), Throughfall, Interception, Snowmelt (mm per day), Drainage, i.e. water melted or precipitated that is above field capacity runs off with a small delay (see parameter tau), Canopywater for surfacial water storage (upper limit set by parameter Cmax and fAPAR), S season status (C) for fS calculation.

See Also

Package information: Rpreles

Examples

## Run model with artificial inputs
CO2 <- 280:(2*380)
T=rep(18, length(CO2))
fAPAR=rep(1, length(CO2))
Precip=rep(3, length(CO2))
PAR=rep(20, length(CO2))

## Plot CO2 effect on GPP, ET, and SW. Feedbacks through soil
## eliminated with high precipitation
pdf('testCO2.pdf', hei=10, wid=10)
op <- par(mfrow=c(4,4), mar=c(1,1,1,1), oma=c(4,4,4,4))
for (D in c(0, 0.5, 1, 1.5)) {
    D <- rep(D, length(CO2))
    o1 <- PRELES(PAR, T, D, Precip, CO2, fAPAR,
  returncols=c("GPP", "ET", "SW", "fW", "fE"), LOGFLAG=0)
    plot(CO2, o1$GPP)
abline(v=380)
    plot(CO2, o1$ET)
abline(v=380)
    plot(CO2, o1$GPP/o1$ET)
abline(v=380)
    plot(CO2, o1$SW)
abline(v=380)
}

ForModLabUHel/Rprebasso documentation built on April 13, 2025, 10:48 a.m.