so17_eqn27: so17_eqn27: Approximate leaf temperature using equation 27 of...
In muir-lab/tleavesMC: Schymanski Equation

Description Usage Arguments Details Value Examples

so17_eqn27: Approximate leaf temperature using equation 27 of Schymanski and Or 2017

so17_eqn27(
  leaf_par,
  enviro_par,
  constants,
  progress = TRUE,
  quiet = FALSE,
  set_units = TRUE
)

`leaf_par`	A list of leaf parameters. This can be generated using the `make_leafpar` function.
`enviro_par`	A list of environmental parameters. This can be generated using the `make_enviropar` function.
`constants`	A list of physical constants. This can be generated using the `make_constants` function.
`progress`	Logical. Should a progress bar be displayed?
`quiet`	Logical. Should messages be displayed?
`set_units`	Logical. Should `units` be set? The function is faster when FALSE, but input must be in correct units or else results will be incorrect without any warning.

Schymanski and Or function can be used to obtain analytical expressions for H, L, and S_r that satisfy the energy balance (S_r). Alternatively, the value of T_leaf obtained from the Schymanski and Or function for specific conditions could be used to calculate any of the energy balance components using the fundamental equations. In this case, bias in T_leaf due to simplifying assumptions included in the derivation of Schymanski and Or function could lead to a mismatch in the leaf energy balance calculation.

Below is the same equation as Schymanski and Or 2017 but with variable nomenclature consistent with tealeaves:

T_leaf = (S_r + H (T_air) + ? (? + ? - p_sat) + ?(alpha_l)sigma(3T_air^4 = ?^4)) / (H + L? + 4?alpha_l sigma T_air^3)

Below is the original Schymanski and Or 2017 equation:

T_l = (R_s + C_H(T_a) + C_E(delta_eTa + P_wa - P_was) + a_sh(epsilon_l)sigma(3T_a^4 = T_w^4)) / (C_H + C_E(delta_eTa) + 4a_sh(epsilon_l)sigma(T_a^3))

Symbol	S & O 2017	R	Description	Units
T_leaf	T_l	`T_leaf`	leaf temperature	K
S_r	R_s	`S_r`	absorbed short-wave radiation	W m^-2
?	C_H	`?`	transfer coefficients for latent sensible heat	unitless
T_air	T_a	`T_air`	leaf temperature	K
?	C_E	`?`	transfer coefficients for latent heat	unitless
?	delta_eTa	`?`	slope of saturation vapour pressure at air temperature	unitless
?	P_wa	`?`	vapour pressure in the atmosphere	kPa
p_sat	P_was	`p_sat`	saturating water vapour pressure	kPa
?	a_sh	`?`	fraction of projected area exchanging sensible heat with the air	1
alpha_l	epsilon_l	`abs_l`	absorbtivity of long-wave radiation	unitless
signma	s	`signma`	Stefan–Boltzmann constant	W K^-1 m^-2
T_air	T_air	`T_a`	Stefan–Boltzmann constant	K
?	T_w	`?`	surroundings temperature	K

Value in degrees Kelvin (K) of class units

library(tealeaves)

leaf_par <- make_leafpar()
enviro_par <- make_enviropar()
constants <- make_constants()
tleaf(leaf_par, enviro_par, constants)

tealeaves:::so17_eqn27(leaf_par, enviro_par, constants)