d_wv: water vapour gradient (mol / m ^ 3)

d_wv: water vapour gradient (mol / m ^ 3)

.get_dwv(T_leaf, pars, unitless)

Arguments

T_leaf

Leaf temperature in Kelvin

pars

Concatenated parameters (leaf_par, enviro_par, and constants)

unitless

Logical. Should function use parameters with units? The function is faster when FALSE, but input must be in correct units or else results will be incorrect without any warning.

Value

Value in mol / m^3 of class units

Details

Water vapour gradient: The water vapour pressure differential from inside to outside of the leaf is the saturation water vapor pressure inside the leaf (p_leaf) minus the water vapor pressure of the air (p_air):

$$d_\mathrm{wv} = p_\mathrm{leaf} / (R T_\mathrm{leaf}) - RH p_\mathrm{air} / (R T_\mathrm{air})$$

Note that water vapor pressure is converted from kPa to mol / m^3 using ideal gas law.

Symbol	R	Description	Units	Default
\(p_\mathrm{air}\)	p_air	saturation water vapour pressure of air	kPa	calculated
\(p_\mathrm{leaf}\)	p_leaf	saturation water vapour pressure inside the leaf	kPa	calculated
\(R\)	R	ideal gas constant	J / (mol K)	8.3144598
\(\mathrm{RH}\)	RH	relative humidity	%	0.50
\(T_\mathrm{air}\)	T_air	air temperature	K	298.15
\(T_\mathrm{leaf}\)	T_leaf	leaf temperature	K	input

Examples

# Water vapour gradient: 

leaf_par <- make_leafpar()
enviro_par <- make_enviropar()
constants <- make_constants()
pars <- c(leaf_par, enviro_par, constants)
T_leaf <- set_units(300, K)
T_air <- set_units(298.15, K)
p_leaf <- set_units(35.31683, kPa)
p_air <- set_units(31.65367, kPa)

d_wv <- p_leaf / (pars$R * T_leaf) - pars$RH * p_air / (pars$R * T_air)