Rutils/maybe-not-useful/rshort.bdown.r
In manfredo89/ED2io: Manages Input/Output for Ecosystem Demography 2 Model
#==========================================================================================#
#==========================================================================================#
# This subroutine computes the split between direct and diffuse radiation, and #
# between visible and near-infrared radiation using the method suggested by: #
# #
# Weiss, A., J. M. Norman, 1985: Partitioning solar radiation into direct and diffuse, #
# visible and near-infrared components. Agric. For. Meteorol., 34, 205-213. (WN85) #
# #
# Input variables: #
# #
# * rad.in - The incoming radiation at surface, in W/m2. This can be either PAR, #
# NIR, or the total shortwave radiation, but it must be in W/m2 in any of #
# the cases. #
# * atm.prss - The atmospheric pressure at the surface, in Pa. An actual measurement #
# is better, but if you don't have one just use some typical value given #
# the place altitude (higher elevation sites get more radiation). #
# * cosz - The cosine of zenith angle. This can be estimated using function ed.zen #
# in file zen.r
# * rad.type - The type of radiation provided in rad.in. Default is total shortwave #
# radiation, but the function also accepts PAR or NIR. The value is case #
# insensitive and only the first letter is checked. "p" means PAR, "n" #
# means NIR, and any other letter will be assumed shortwave. #
#------------------------------------------------------------------------------------------#
rshort.bdown = function(rad.in,atm.prss,cosz,rad.type="rshort"){
if (length(atm.prss) == 1) atm.prss = rep(atm.prss,times=length(rad.in))
#---------------------------------------------------------------------------------------#
# Local constants. #
#---------------------------------------------------------------------------------------#
#----- Extinction coefficient. (equations 1 and 4 of WN85) -----------------------------#
par.beam.expext = -0.185
nir.beam.expext = -0.060
#----- This is the typical conversion of diffuse radiation in sunny days. --------------#
par2diff.sun = 0.400
nir2diff.sun = 0.600
#----- Coefficients for various equations in WN85. -------------------------------------#
wn85.06 = c( -1.1950, 0.4459, -0.0345 )
wn85.11 = c( 0.90, 0.70 )
wn85.12 = c( 0.88, 0.68 )
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Make rad type case insensitive, and retain only the first letter. #
#---------------------------------------------------------------------------------------#
rty = substring(tolower(rad.type),1,1)
#---------------------------------------------------------------------------------------#
#------ Initialise the radiation with NAs. ---------------------------------------------#
par.beam = NA * rad.in
nir.beam = NA * rad.in
par.diff = NA * rad.in
nir.diff = NA * rad.in
par.full = NA * rad.in
nir.full = NA * rad.in
rshort.beam = NA * rad.in
rshort.diff = NA * rad.in
rshort.full = NA * rad.in
par.max = NA * rad.in
nir.max = NA * rad.in
rshort.max = NA * rad.in
#------ Make day and night flags. ------------------------------------------------------#
ntimes = length(cosz)
night = cosz <= cosz.min
day = ! night
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# First thing to check is whether this is daytime or "night-time". If the zenith #
# angle is too close to horizon, we assume it's dawn/dusk and all radiation goes to #
# diffuse. #
#---------------------------------------------------------------------------------------#
par.beam [night] = 0.0
nir.beam [night] = 0.0
if (rty %in% "p"){
par.diff [night] = rad.in[night]
nir.diff [night] = fnir.diff.def * rad.in[night] / fvis.diff.def
}else if(rty %in% "n"){
par.diff [night] = fvis.diff.def * rad.in[night] / fnir.diff.def
nir.diff [night] = rad.in[night]
}else{
par.diff [night] = fvis.diff.def * rad.in[night]
nir.diff [night] = fnir.diff.def * rad.in[night]
}#end if
par.full [night] = par.beam [night] + par.diff [night]
nir.full [night] = nir.beam [night] + nir.diff [night]
rshort.beam [night] = par.beam [night] + nir.beam [night]
rshort.diff [night] = par.diff [night] + nir.diff [night]
rshort.full [night] = rshort.beam[night] + rshort.diff[night]
par.max [night] = 0.0
nir.max [night] = 0.0
rshort.max [night] = 0.0
#---------------------------------------------------------------------------------------#
#----- Save 1/cos(zen), which is the secant. We will use this several times. ----------#
secz = 1. / cosz[day]
log10secz = log10(secz)
#---------------------------------------------------------------------------------------#
#----- Total radiation at the top [ W/m2], using ED defaults. -------------------------#
par.beam.top = fvis.beam.def * solar
nir.beam.top = fnir.beam.def * solar
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the potential PAR components (beam, diffuse, total), using equations 1, 3, #
# and 9 of WN85. #
#---------------------------------------------------------------------------------------#
par.beam.pot = ( par.beam.top
* exp ( par.beam.expext * (atm.prss[day] / prefsea) * secz) * cosz[day])
par.diff.pot = par2diff.sun * (par.beam.top - par.beam.pot) * cosz[day]
par.full.pot = par.beam.pot + par.diff.pot
#------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the NIR absorption of 10 mm of precipitable water, using WN85 equation 6. #
#---------------------------------------------------------------------------------------#
w10 = solar * 10 ** ((wn85.06[1]) + log10secz * (wn85.06[2] + wn85.06[3] * log10secz))
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the potential direct and diffuse near-infrared radiation, using equations #
# 4, 5, and 10 of WN85. #
#---------------------------------------------------------------------------------------#
nir.beam.pot = ( ( nir.beam.top
* exp ( nir.beam.expext * (atm.prss[day] / prefsea) * secz) - w10 )
* cosz[day] )
nir.diff.pot = nir2diff.sun * ( nir.beam.top - nir.beam.pot - w10 ) * cosz[day]
nir.full.pot = nir.beam.pot + nir.diff.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Total maximum radiation. #
#---------------------------------------------------------------------------------------#
par.max [day] = par.full.pot
nir.max [day] = nir.full.pot
rshort.max[day] = par.full.pot + nir.full.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the actual total for PAR and NIR, using equations 7 and 8. #
#---------------------------------------------------------------------------------------#
if (rty == "p"){
ratio = rad.in[day] / par.full.pot
}else if (rty == "n"){
ratio = rad.in[day] / nir.full.pot
}else{
ratio = rad.in[day] / (par.full.pot + nir.full.pot)
}#end if
par.full[day] = ratio * par.full.pot
nir.full[day] = ratio * nir.full.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the fraction of PAR and NIR that stays as beam, using equations 11 and 12 #
# of WN85. #
#---------------------------------------------------------------------------------------#
#----- Make sure that the ratio is bounded. --------------------------------------------#
aux.par = pmin(wn85.11[1],pmax(0.,ratio))
aux.nir = pmin(wn85.12[1],pmax(0.,ratio))
fvis.beam.act = ( par.beam.pot
* (1. - ((wn85.11[1] - aux.par)/wn85.11[2]) ^ twothirds)
/ par.full.pot )
fvis.beam.act = pmin(1.,pmax(0.,fvis.beam.act))
fnir.beam.act = ( nir.beam.pot
* (1. - ((wn85.12[1] - aux.nir)/wn85.12[2]) ^ twothirds)
/ nir.full.pot )
fnir.beam.act = pmin(1.,pmax(0.,fvis.beam.act))
fvis.diff.act = 1. - fvis.beam.act
fnir.diff.act = 1. - fnir.beam.act
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the radiation components. #
#---------------------------------------------------------------------------------------#
par.beam [day] = fvis.beam.act * par.full[day]
par.diff [day] = fvis.diff.act * par.full[day]
nir.beam [day] = fnir.beam.act * nir.full[day]
nir.diff [day] = fnir.diff.act * nir.full[day]
rshort.beam [day] = par.beam [day] + nir.beam [day]
rshort.diff [day] = par.diff [day] + nir.diff [day]
rshort.full [day] = rshort.beam[day] + rshort.diff[day]
#---------------------------------------------------------------------------------------#
rshort.bdown = list( par.beam = par.beam
, par.diff = par.diff
, par.full = par.full
, nir.beam = nir.beam
, nir.diff = nir.diff
, nir.full = nir.full
, rshort.beam = rshort.beam
, rshort.diff = rshort.diff
, rshort.full = rshort.full
, par.max = par.max
, nir.max = nir.max
, rshort.max = rshort.max
)#end list
return(rshort.bdown)
}#end function rshort.bdown
#==========================================================================================#
#==========================================================================================#
manfredo89/ED2io documentation built on May 21, 2019, 11:24 a.m.
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
#==========================================================================================#
#==========================================================================================#
# This subroutine computes the split between direct and diffuse radiation, and #
# between visible and near-infrared radiation using the method suggested by: #
# #
# Weiss, A., J. M. Norman, 1985: Partitioning solar radiation into direct and diffuse, #
# visible and near-infrared components. Agric. For. Meteorol., 34, 205-213. (WN85) #
# #
# Input variables: #
# #
# * rad.in - The incoming radiation at surface, in W/m2. This can be either PAR, #
# NIR, or the total shortwave radiation, but it must be in W/m2 in any of #
# the cases. #
# * atm.prss - The atmospheric pressure at the surface, in Pa. An actual measurement #
# is better, but if you don't have one just use some typical value given #
# the place altitude (higher elevation sites get more radiation). #
# * cosz - The cosine of zenith angle. This can be estimated using function ed.zen #
# in file zen.r
# * rad.type - The type of radiation provided in rad.in. Default is total shortwave #
# radiation, but the function also accepts PAR or NIR. The value is case #
# insensitive and only the first letter is checked. "p" means PAR, "n" #
# means NIR, and any other letter will be assumed shortwave. #
#------------------------------------------------------------------------------------------#
rshort.bdown = function(rad.in,atm.prss,cosz,rad.type="rshort"){
if (length(atm.prss) == 1) atm.prss = rep(atm.prss,times=length(rad.in))
#---------------------------------------------------------------------------------------#
# Local constants. #
#---------------------------------------------------------------------------------------#
#----- Extinction coefficient. (equations 1 and 4 of WN85) -----------------------------#
par.beam.expext = -0.185
nir.beam.expext = -0.060
#----- This is the typical conversion of diffuse radiation in sunny days. --------------#
par2diff.sun = 0.400
nir2diff.sun = 0.600
#----- Coefficients for various equations in WN85. -------------------------------------#
wn85.06 = c( -1.1950, 0.4459, -0.0345 )
wn85.11 = c( 0.90, 0.70 )
wn85.12 = c( 0.88, 0.68 )
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Make rad type case insensitive, and retain only the first letter. #
#---------------------------------------------------------------------------------------#
rty = substring(tolower(rad.type),1,1)
#---------------------------------------------------------------------------------------#
#------ Initialise the radiation with NAs. ---------------------------------------------#
par.beam = NA * rad.in
nir.beam = NA * rad.in
par.diff = NA * rad.in
nir.diff = NA * rad.in
par.full = NA * rad.in
nir.full = NA * rad.in
rshort.beam = NA * rad.in
rshort.diff = NA * rad.in
rshort.full = NA * rad.in
par.max = NA * rad.in
nir.max = NA * rad.in
rshort.max = NA * rad.in
#------ Make day and night flags. ------------------------------------------------------#
ntimes = length(cosz)
night = cosz <= cosz.min
day = ! night
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# First thing to check is whether this is daytime or "night-time". If the zenith #
# angle is too close to horizon, we assume it's dawn/dusk and all radiation goes to #
# diffuse. #
#---------------------------------------------------------------------------------------#
par.beam [night] = 0.0
nir.beam [night] = 0.0
if (rty %in% "p"){
par.diff [night] = rad.in[night]
nir.diff [night] = fnir.diff.def * rad.in[night] / fvis.diff.def
}else if(rty %in% "n"){
par.diff [night] = fvis.diff.def * rad.in[night] / fnir.diff.def
nir.diff [night] = rad.in[night]
}else{
par.diff [night] = fvis.diff.def * rad.in[night]
nir.diff [night] = fnir.diff.def * rad.in[night]
}#end if
par.full [night] = par.beam [night] + par.diff [night]
nir.full [night] = nir.beam [night] + nir.diff [night]
rshort.beam [night] = par.beam [night] + nir.beam [night]
rshort.diff [night] = par.diff [night] + nir.diff [night]
rshort.full [night] = rshort.beam[night] + rshort.diff[night]
par.max [night] = 0.0
nir.max [night] = 0.0
rshort.max [night] = 0.0
#---------------------------------------------------------------------------------------#
#----- Save 1/cos(zen), which is the secant. We will use this several times. ----------#
secz = 1. / cosz[day]
log10secz = log10(secz)
#---------------------------------------------------------------------------------------#
#----- Total radiation at the top [ W/m2], using ED defaults. -------------------------#
par.beam.top = fvis.beam.def * solar
nir.beam.top = fnir.beam.def * solar
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the potential PAR components (beam, diffuse, total), using equations 1, 3, #
# and 9 of WN85. #
#---------------------------------------------------------------------------------------#
par.beam.pot = ( par.beam.top
* exp ( par.beam.expext * (atm.prss[day] / prefsea) * secz) * cosz[day])
par.diff.pot = par2diff.sun * (par.beam.top - par.beam.pot) * cosz[day]
par.full.pot = par.beam.pot + par.diff.pot
#------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the NIR absorption of 10 mm of precipitable water, using WN85 equation 6. #
#---------------------------------------------------------------------------------------#
w10 = solar * 10 ** ((wn85.06[1]) + log10secz * (wn85.06[2] + wn85.06[3] * log10secz))
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the potential direct and diffuse near-infrared radiation, using equations #
# 4, 5, and 10 of WN85. #
#---------------------------------------------------------------------------------------#
nir.beam.pot = ( ( nir.beam.top
* exp ( nir.beam.expext * (atm.prss[day] / prefsea) * secz) - w10 )
* cosz[day] )
nir.diff.pot = nir2diff.sun * ( nir.beam.top - nir.beam.pot - w10 ) * cosz[day]
nir.full.pot = nir.beam.pot + nir.diff.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Total maximum radiation. #
#---------------------------------------------------------------------------------------#
par.max [day] = par.full.pot
nir.max [day] = nir.full.pot
rshort.max[day] = par.full.pot + nir.full.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the actual total for PAR and NIR, using equations 7 and 8. #
#---------------------------------------------------------------------------------------#
if (rty == "p"){
ratio = rad.in[day] / par.full.pot
}else if (rty == "n"){
ratio = rad.in[day] / nir.full.pot
}else{
ratio = rad.in[day] / (par.full.pot + nir.full.pot)
}#end if
par.full[day] = ratio * par.full.pot
nir.full[day] = ratio * nir.full.pot
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the fraction of PAR and NIR that stays as beam, using equations 11 and 12 #
# of WN85. #
#---------------------------------------------------------------------------------------#
#----- Make sure that the ratio is bounded. --------------------------------------------#
aux.par = pmin(wn85.11[1],pmax(0.,ratio))
aux.nir = pmin(wn85.12[1],pmax(0.,ratio))
fvis.beam.act = ( par.beam.pot
* (1. - ((wn85.11[1] - aux.par)/wn85.11[2]) ^ twothirds)
/ par.full.pot )
fvis.beam.act = pmin(1.,pmax(0.,fvis.beam.act))
fnir.beam.act = ( nir.beam.pot
* (1. - ((wn85.12[1] - aux.nir)/wn85.12[2]) ^ twothirds)
/ nir.full.pot )
fnir.beam.act = pmin(1.,pmax(0.,fvis.beam.act))
fvis.diff.act = 1. - fvis.beam.act
fnir.diff.act = 1. - fnir.beam.act
#---------------------------------------------------------------------------------------#
#---------------------------------------------------------------------------------------#
# Find the radiation components. #
#---------------------------------------------------------------------------------------#
par.beam [day] = fvis.beam.act * par.full[day]
par.diff [day] = fvis.diff.act * par.full[day]
nir.beam [day] = fnir.beam.act * nir.full[day]
nir.diff [day] = fnir.diff.act * nir.full[day]
rshort.beam [day] = par.beam [day] + nir.beam [day]
rshort.diff [day] = par.diff [day] + nir.diff [day]
rshort.full [day] = rshort.beam[day] + rshort.diff[day]
#---------------------------------------------------------------------------------------#
rshort.bdown = list( par.beam = par.beam
, par.diff = par.diff
, par.full = par.full
, nir.beam = nir.beam
, nir.diff = nir.diff
, nir.full = nir.full
, rshort.beam = rshort.beam
, rshort.diff = rshort.diff
, rshort.full = rshort.full
, par.max = par.max
, nir.max = nir.max
, rshort.max = rshort.max
)#end list
return(rshort.bdown)
}#end function rshort.bdown
#==========================================================================================#
#==========================================================================================#
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