R_abs: total absorbed radiation (W / m^2)
R_abs: total absorbed radiation (W / m^2)
.get_Rabs(pars, unitless)
pars |
Concatenated parameters ( |
unitless |
Logical. Should function use parameters with |
The following treatment follows Okajima et al. (2012):
R_abs = α_s (1 + r) S_sw + α_l σ (T_sky ^ 4 + T_air ^ 4)
The incident longwave (aka thermal infrared) radiation is modeled from sky and air temperature σ (T_sky ^ 4 + T_air ^ 4) where T_sky is function of the air temperature and incoming solar shortwave radiation:
T_sky = T_air - 20 S_sw / 1000
| Symbol | R | Description | Units | Default |
| α_s | abs_s |
absorbtivity of shortwave radiation (0.3 - 4 μm) | none | 0.80 |
| α_l | abs_l |
absorbtivity of longwave radiation (4 - 80 μm) | none | 0.97 |
| r | r |
reflectance for shortwave irradiance (albedo) | none | 0.2 |
| σ | s |
Stefan-Boltzmann constant | W / (m^2 K^4) | 5.67e-08 |
| S_sw | S_sw |
incident short-wave (solar) radiation flux density | W / m^2 | 1000 |
| S_lw | S_lw |
incident long-wave radiation flux density | W / m^2 | calculated |
| T_air | T_air |
air temperature | K | 298.15 |
| T_sky | T_sky |
sky temperature | K | calculated |
Value in W / m^2 of class units
Okajima Y, H Taneda, K Noguchi, I Terashima. 2012. Optimum leaf size predicted by a novel leaf energy balance model incorporating dependencies of photosynthesis on light and temperature. Ecological Research 27: 333-46.
library(tealeaves) cs <- make_constants() ep <- make_enviropar() lp <- make_leafpar() ep$T_sky <- ep$T_sky(ep) tealeaves:::.get_Rabs(c(cs, ep, lp), FALSE)
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