Description Usage Arguments Details Value Author(s) References See Also Examples
It represents an integration of the photosynthesis function
c3photo
, canopy evapo/transpiration and the
multilayer canopy model sunML
.
1 2 3 4 |
lai |
leaf area index. |
doy |
day of the year, (1–365). |
hr |
hour of the day, (0–23). |
solar |
solar radiation (micro mol m-2 s-1). |
temp |
temperature (Celsius). |
rh |
relative humidity (0–1). |
windspeed |
wind speed (m s-1). |
lat |
latitude. |
nlayers |
number of layers in the simulation of the canopy (max allowed is 50). |
kd |
Ligth extinction coefficient for diffuse light. |
heightFactor |
Height Factor. Divide LAI by this number to get the height of a crop. |
c3photoControl |
list that sets the photosynthesis parameters for c3 plants through the c3photoParms function |
lnControl |
list that sets the leaf nitrogen parameters. LeafN: Initial value of leaf nitrogen (g m-2). kpLN: coefficient of decrease in leaf nitrogen during the growing season. The equation is LN = iLeafN * exp(-kLN * TTc). lnFun: controls whether there is a decline in leaf nitrogen with the depth of the canopy. 'none' means no decline, 'linear' means a linear decline controlled by the following two parameters. lnb0: Intercept of the linear decline of leaf nitrogen in the depth of the canopy. lnb1: Slope of the linear decline of leaf nitrogen in the depth of the canopy. The equation is 'vmax = leafN_lay * lnb1 + lnb0'. |
The photosynthesis function is modeled after the version in WIMOVAC. This is based on the well known Farquar model.
list
returns a list with several elements
CanopyAssim: hourly canopy assimilation (Mg/ha per hour)
CanopyTrans: hourly canopy transpiration (Mg/ha per hour)
CanopyCond: hourly canopy conductance (units ?)
TranEpen: hourly canopy transpiration according to Penman (Mg ha^{-1} per hour)
TranEpen: hourly canopy transpiration according to Priestly (Mg/ha per hour)
LayMat: hourly by Layer matrix containing details of the calculations by layer (each layer is a row). col1: Direct Irradiance col2: Diffuse Irradiance col3: Leaf area in the sun col4: Leaf area in the shade col5: Transpiration of leaf area in the sun col6: Transpiration of leaf area in the shade col7: Assimilation of leaf area in the sun col8: Assimilation of leaf area in the shade col9: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in sun. col10: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in shade. col11: Stomatal conductance for leaves in the sun col12: Stomatal conductance for leaves in the shade col13: Nitrogen concentration in the leaf (g m^-2) col14: Vmax value as depending on leaf nitrogen
Fernando E. Miguez
Farquhar model
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | data(doy124)
tmp <- numeric(24)
for(i in 1:24){
lai <- doy124[i,1]
doy <- doy124[i,3]
hr <- doy124[i,4]
solar <- doy124[i,5]
temp <- doy124[i,6]
rh <- doy124[i,7]
ws <- doy124[i,8]
tmp[i] <- c3CanA(lai,doy,hr,solar,temp,rh,ws)$CanopyAssim
}
plot(c(0:23),tmp,
type="l",lwd=2,
xlab="Hour",
ylab=expression(paste("Canopy assimilation (Mg ",
ha^-2," ",h^-1,")")))
|
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