Description Usage Arguments Value Examples
It represents an integration of the photosynthesis function
c4photo
, canopy evapo/transpiration and the
multilayer canopy model sunML
.
1 2 3 4 5 6 7 |
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. |
stress |
coefficient controlling the effect of water stress on stomatal conductance and assimilation. |
chi.l |
The ratio of horizontal to vertical projected area of leaves in the canopy segment. A smaller than 1 value represents a more upright canopy and a value higher than 1 is represented by more horizontal leaves. |
leafwidth |
average leaf width. |
heightFactor |
Height Factor. Divide LAI by this number to get the height of a crop. |
photoControl |
list that sets the photosynthesis parameters. See
|
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 * (CumLAI-(LAI/nlayers))). 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 vmax in the depth of the canopy. In this function this parameter together with lnb1 will override the vmax value set in photoControl. lnb1: Slope of the linear decline of leaf nitrogen in the depth of the canopy. The equation is 'vmax = leafN_lay * lnb1 + lnb0'. |
units |
Whether to return units in kg/m2/hr or Mg/ha/hr. This is typically run at hourly intervals, that is why the hr is kept, but it could be used with data at finer timesteps and then convert the results. |
list
returns a list with several elements
CanopyAssim: hourly canopy assimilation (kg/m2 per hour) or canopy assimilation (Mg/ha per hour)
CanopyTrans: hourly canopy transpiration (kg/m2 per hour) or canopy transpiration (Mg/ha per hour)
CanopyCond: hourly canopy conductance (mmol/m2/s)
TranEpen: hourly canopy transpiration according to Penman (kg m^{-2} per hour) or canopy transpiration according to Penman (Mg ha^{-1} per hour)
TranEpries: hourly canopy transpiration according to Priestly (kg/m2 per hour) 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 (micro mol/m2/s) col2: Diffuse Irradiance (micro mol/m2/s) col3: Leaf area in the sun (m2/m2) col4: Leaf area in the shade (m2/m2) col5: Transpiration of leaf area in the sun (kg/m2/h) col6: Transpiration of leaf area in the shade (kg/m2/h) col7: Assimilation of leaf area in the sun (micro mol/m2/s) col8: Assimilation of leaf area in the shade (micro mol/m2/s) col9: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in sun (units = C). col10: Difference in temperature between the leaf and the air (i.e. TLeaf - TAir) for leaves in shade (units = C). 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 col15: Relative humidty (0-1) col16: Wind speed (m/s) col17: Canopy height (m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | ## Not run:
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] <- CanA(lai,doy,hr,solar,temp,rh,ws)$CanopyAssim
}
plot(c(0:23),tmp,
type="l",lwd=2,
xlab="Hour",
ylab=expression(paste("Canopy assimilation (kg ",
m^-2," ",h^-1,")")))
## End(Not run)
|
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