dot-get_Sr.RdS_r: longwave re-radiation (W / m^2)
.get_Sr(T_leaf, pars)Leaf temperature in Kelvin
Concatenated parameters (leaf_par, enviro_par, and constants)
Value in W / m\(^2\) of class units
$$S_\mathrm{r} = 2 \sigma \alpha_\mathrm{l} T_\mathrm{air} ^ 4$$
The factor of 2 accounts for re-radiation from both leaf surfaces (Foster and Smith 1986).
| Symbol | R | Description | Units | Default |
| \(\alpha_\mathrm{l}\) | abs_l | absorbtivity of longwave radiation (4 - 80 \(\mu\)m) | none | 0.97 |
| \(T_\mathrm{air}\) | T_air | air temperature | K | 298.15 |
| \(\sigma\) | s | Stefan-Boltzmann constant | W / (m\(^2\) K\(^4\)) | 5.67e-08 |
Note that leaf absorbtivity is the same value as leaf emissivity
Foster JR, Smith WK. 1986. Influence of stomatal distribution on transpiration in low-wind environments. Plant, Cell & Environment 9: 751-9.
library(tealeaves)
cs <- make_constants()
ep <- make_enviropar()
lp <- make_leafpar()
T_leaf <- set_units(298.15, K)
tealeaves:::.get_Sr(T_leaf, c(cs, ep, lp))
#> 869.2087 [W/m^2]