Convert energy spectral irradiance to molar photon flux.
Source:R/n2W_spec_irradiance.R
W2mol_spec_irradiance.RdConverts W m\(^{-2}\) nm\(^{-1}\) spectral irradiance to a
photon-count flux expressed in molar units (mol, mmol, or µmol photons
m\(^{-2}\) s\(^{-1}\) nm\(^{-1}\)). The inverse operation is
n2W_spec_irradiance. The same per-bin conversion factor
applies to spectral radiance (W m\(^{-2}\) sr\(^{-1}\)
nm\(^{-1}\)).
Usage
W2mol_spec_irradiance(W, ...)
# S3 method for class 'numeric'
W2mol_spec_irradiance(W, lambda, molar_unit = "umol", ...)
# S3 method for class 'lux_spectrum'
W2mol_spec_irradiance(W, molar_unit = "umol", ...)Value
Numeric vector of photon flux in the requested molar unit per nm,
or a lux_spectrum with the updated unit. Radiance outputs retain
the "/sr" term.
Details
The inverse of n2W_spec_irradiance: photon flux is recovered
via \(N = E\lambda/(hc)\), then divided by Avogadro's constant scaled to
the requested molar unit:
$$\Phi(\lambda) = \frac{E(\lambda)\,\lambda}{hc\,N_A} \times s$$
where \(N_A = 6.022 \times 10^{23}\) mol\(^{-1}\) and \(s = 10^6\)
for "umol", \(10^3\) for "mmol", or \(1\) for "mol".
Examples
sp <- solar_irradiance("clear_noon")
W2mol_spec_irradiance(sp$irradiance, sp$wavelength, molar_unit = "umol")
#> [1] 0.00000000 0.02591398 0.37449876 0.99309045 1.84741574 2.60393666
#> [7] 3.37048880 3.77340934 3.55773818 3.32534833 3.34373889 4.18134548
#> [13] 5.02062395 5.28394338 5.55395030 5.86826175 6.15247956 6.52196271
#> [19] 6.90147707 7.29102265 7.69059945 8.01494212 8.25903506 8.41786266
#> [25] 8.48640931 8.50563581 8.47303435 8.38609714 8.33928480 8.23646482
#> [31] 8.12528551 8.00574684 7.87784883 7.74159147 7.59697476 7.44399871
#> [37] 7.28266331 7.05696093 6.82122734 6.57546253 6.31966651 6.05383926
#> [43] 5.77798080 5.49209113 5.19617024 4.89021813 4.57423480 4.24822026
#> [49] 3.91217450 3.56609753 3.20998934