S_r: longwave re-radiation (W / m^2)
S_r: longwave re-radiation (W / m^2)
.get_Sr(T_leaf, pars)
T_leaf |
Leaf temperature in Kelvin |
pars |
Concatenated parameters ( |
S_r = 2 σ α_l T_air ^ 4
The factor of 2 accounts for re-radiation from both leaf surfaces (Foster and Smith 1986).
| Symbol | R | Description | Units | Default |
| α_l | abs_l |
absorbtivity of longwave radiation (4 - 80 μm) | none | 0.97 |
| T_air | T_air |
air temperature | K | 298.15 |
| σ | s |
Stefan-Boltzmann constant | W / (m^2 K^4) | 5.67e-08 |
Note that leaf absorbtivity is the same value as leaf emissivity
Value in W / m^2 of class units
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))
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