Reference solar spectral irradiance under standard conditions.
Source:R/solar_irradiance.R
solar_irradiance.RdReturns a reference spectrum from the bundled solar_spectra dataset,
based on ASTM G173-03 global-tilt values scaled to several representative
illumination conditions. Intended for use as the reference shape in
broadband2spectrum and lux2irradiance.
Value
A data frame with columns wavelength (nm) and
irradiance (W/m^2/nm). Attributes record condition,
reference_depth_m (metres relative to the water surface), and
reference_medium ("air" or "water").
Details
Available conditions:
"clear_noon"Full-sun midday irradiance (ASTM G173-03 GTI).
"clear_dawn"Clear sky near sunrise/sunset (~35% of noon).
"overcast"Overcast diffuse sky (~22% of noon).
"underwater_1m"ASTM GTI attenuated through 1 m of Jerlov IA water.
"underwater_10m"ASTM GTI attenuated through 10 m of Jerlov IA water.
The historical underwater sources span 300–800 nm and were generated with constant endpoint extension beyond the bundled Jerlov dataset's supported 350–700 nm domain. Their attributes explicitly record this assumption and the Jerlov table checksum so it is not a silent extrapolation path.
Examples
solar_irradiance("clear_noon")
#> wavelength irradiance
#> 1 300 0.00
#> 2 310 0.01
#> 3 320 0.14
#> 4 330 0.36
#> 5 340 0.65
#> 6 350 0.89
#> 7 360 1.12
#> 8 370 1.22
#> 9 380 1.12
#> 10 390 1.02
#> 11 400 1.00
#> 12 410 1.22
#> 13 420 1.43
#> 14 430 1.47
#> 15 440 1.51
#> 16 450 1.56
#> 17 460 1.60
#> 18 470 1.66
#> 19 480 1.72
#> 20 490 1.78
#> 21 500 1.84
#> 22 510 1.88
#> 23 520 1.90
#> 24 530 1.90
#> 25 540 1.88
#> 26 550 1.85
#> 27 560 1.81
#> 28 570 1.76
#> 29 580 1.72
#> 30 590 1.67
#> 31 600 1.62
#> 32 610 1.57
#> 33 620 1.52
#> 34 630 1.47
#> 35 640 1.42
#> 36 650 1.37
#> 37 660 1.32
#> 38 670 1.26
#> 39 680 1.20
#> 40 690 1.14
#> 41 700 1.08
#> 42 710 1.02
#> 43 720 0.96
#> 44 730 0.90
#> 45 740 0.84
#> 46 750 0.78
#> 47 760 0.72
#> 48 770 0.66
#> 49 780 0.60
#> 50 790 0.54
#> 51 800 0.48
broadband2spectrum(480, unit = "W", spectrum = solar_irradiance("overcast"))
#> wavelength irradiance
#> 1 300 0.000000000
#> 2 310 0.007722008
#> 3 320 0.108108108
#> 4 330 0.277992278
#> 5 340 0.501930502
#> 6 350 0.687258687
#> 7 360 0.864864865
#> 8 370 0.942084942
#> 9 380 0.864864865
#> 10 390 0.787644788
#> 11 400 0.772200772
#> 12 410 0.942084942
#> 13 420 1.104247104
#> 14 430 1.135135135
#> 15 440 1.166023166
#> 16 450 1.204633205
#> 17 460 1.235521236
#> 18 470 1.281853282
#> 19 480 1.328185328
#> 20 490 1.374517375
#> 21 500 1.420849421
#> 22 510 1.451737452
#> 23 520 1.467181467
#> 24 530 1.467181467
#> 25 540 1.451737452
#> 26 550 1.428571429
#> 27 560 1.397683398
#> 28 570 1.359073359
#> 29 580 1.328185328
#> 30 590 1.289575290
#> 31 600 1.250965251
#> 32 610 1.212355212
#> 33 620 1.173745174
#> 34 630 1.135135135
#> 35 640 1.096525097
#> 36 650 1.057915058
#> 37 660 1.019305019
#> 38 670 0.972972973
#> 39 680 0.926640927
#> 40 690 0.880308880
#> 41 700 0.833976834
#> 42 710 0.787644788
#> 43 720 0.741312741
#> 44 730 0.694980695
#> 45 740 0.648648649
#> 46 750 0.602316602
#> 47 760 0.555984556
#> 48 770 0.509652510
#> 49 780 0.463320463
#> 50 790 0.416988417
#> 51 800 0.370656371