Function to describe the light levels inside the canopy

Function to describe the light levels inside the canopy

f.canopy.interception(
  meteo_hourly,
  lat,
  DOY,
  nlayers,
  dLAI,
  LAI,
  Rho = 0.11,
  Tau = 0.06,
  Rho_soil = 0.1,
  Rho_NIR = 0.46,
  Tau_NIR = 0.33,
  Rho_soil_NIR = 0.33,
  chil = 0.32,
  clumpfac = 0.85,
  model = "Norman"
)

Arguments

meteo_hourly

Hourly weather data frame with at least the column time (time in numeric, for example 0 to 23),Tair (air temperature in degree C), RH (humidity in pc from 0 to 100), cs the CO2 concentration and PFD the total PFD in micro mol m-2 s-1.

lat

Latitude of the canopy to model.

DOY

Day of Year .

nlayers

Number of layers inside the canopy (max = 50).

dLAI

LAI of each one of the n layers of vegetation in the canopy.

LAI

Cumulated LAI in the midle of each layer.

Rho

Leaf reflectance in the visible wavelengths.

Tau

Leaf transmittance in the visible wavelengths.

Rho_soil

Soil reflectance in the visible wavelengths.

Rho_NIR

Leaf reflectance in the NIR wavelengths.

Tau_NIR

Leaf transmittance in the NIR wavelengths.

Rho_soil_NIR

Soil reflectance in the NIR wavelengths.

chil

Index of departure of the leaf angles from a spherical distribution. -0.4 < chil < 0.6.

clumpfac

Clumping factor, index of non random spatial distribution of leaves. = 1 for randomly spaced leaves, <1 for clumed leaves (Chen et al. 2012).

model

Model for the radiation interception model, default is Norman (only Norman implemented so far).

Examples

##Simulation of the vegetation
LAItot = 6
nlayers=20
dLAI=rep(6/nlayers,nlayers)
LAI=cumsum(dLAI)-dLAI/2 # LAI in the midle of each layer
##Simulation of the weather
meteo_hourly=data.frame(time=0:23,RH=80,Tair=25,cs=400,PFD=dnorm(x = seq(0,23,1),mean = 12,sd = 2.5)/0.16*2000,Tleaf=25)
##Simulation of position and moment of the simulation
lat=9.2801048
DOY = 60
##Representation of the light interception inside the canopy
canopy=f.canopy.interception(meteo_hourly=meteo_hourly,lat = lat,DOY = DOY,nlayers = nlayers,dLAI = dLAI,LAI=LAI)

#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"
#> [1] "Radiation model for a total LAI of  6"