f.gs.RdSemi-empirical model of the leaf conductance to water vapour
f.gs(
A,
cs,
ds = NULL,
RH = NULL,
Rd = NULL,
g0,
g1,
power = 0.5,
model = "USO"
)Net assimilation in micromol.m-2.s-1, i-e, the assimilation in presence of respiration.
CO2 at the surface of the leaf in ppm.
Leaf surface to air vapour pressure deficit in Pa. Needed for the USO, USO_simpl and Nonlinear models.
Humidity at the surface of the leaf (0 - 100). Only needed for the BWB model.
Dark respiration for the non linear model. Be carefull that the net assimilation is implemented in all the models except the non linear where the gross assimilation is used (A + Rd).
Constant of the USO model, representing the conductance when A is 0, in mol.m-2.s-1
Slope parameter, between 1.14 and 3.58 KPa^0.5 (Wu et al., 2019)
Power of the VPDl in USO model. By default is is 0.5 as in Medlyn publication
Stomatal model ("USO", "USO_simpl" or "BWB" or "Nonlinear")
This function returns the stomatal conductance to water vapour in mol.m-2.s-1
USO : gs=g0+1.6*(1+g1/(ds/1000)^power)*(A)/cs. Cf Medlyn et al. 2011
USO_simpl : gs=g0+1.6*(g1/(ds/1000)^power)*(A)/cs. Cf Medlyn et al. 2011
BWB : gs=g0+g1*(A*RH/100)/cs. Cf Ball et al. 1987
Nonlinear: gs=g0+1.6*(g1/(ds/1000)^power)*(A+Rd)^2/cs. Cf Lamour et al. 2022
Medlyn, B.E., Duursma, R.A., Eamus, D., Ellsworth, D.S., Colin Prentice, I., Barton, C.V.M., Crous, K.Y., de Angelis, P., Freeman, M. and Wingate, L. (2012), Reconciling the optimal and empirical approaches to modelling stomatal conductance. Glob Change Biol, 18: 3476-3476. doi:10.1111/j.1365-2486.2012.02790.x.
Wu, J, Serbin, SP, Ely, KS, et al. The response of stomatal conductance to seasonal drought in tropical forests. Glob Change Biol. 2020; 26: 823– 839. https://doi.org/10.1111/gcb.14820.
Leuning, R., Kelliher, F. M., De Pury, D. G. G., & Schulze, E. D. (1995). Leaf nitrogen, photosynthesis, conductance and transpiration: scaling from leaves to canopies. Plant, Cell & Environment, 18(10), 1183-1200.
Ball, J. T., Woodrow, I. E., & Berry, J. A. (1987). A model predicting stomatal conductance and its contribution to the control of photosynthesis under different environmental conditions. In Progress in photosynthesis research (pp. 221-224). Springer, Dordrecht.
Lamour, J., Davidson, K.J., Ely, K.S., Le Moguédec, G., Leakey, A.D., Li, Q., Serbin, S.P. and Rogers, A., 2022. An improved representation of the relationship between photosynthesis and stomatal conductance leads to more stable estimation of conductance parameters and improves the goodness‐of‐fit across diverse data sets. Global change biology, 28(11), pp.3537-3556.
f.gs(A=30,cs=400,ds=1500,g0=0.01,g1=2,power=0.5)
#> [1] 0.3259592