Sunlight just at noon on a horizontal plane in Lund
LARS OLOF BJÖRN. 2007. The Science of Life and Light. 2nd ed. New York: Springer 978-0-387-72654-0.
Spectrum 31: SUN Edit
DeleteMeasurement
| Brand |
other other |
|---|---|
| Lamp Product |
Sun Direct sunlight |
| Lamp ID |
SUN (01/2000) |
| Spectrometer | - |
| Ballast | - no ballast or default/unknown ballast - |
| Reflector | |
| Distance | 0 cm |
| Age | 0 hours |
| Originator (measurement) | Publication |
Database entry created:
Sarina Wunderlich
28/Jan/2010 ; updated:
Sarina Wunderlich
9/Oct/2011
Colorimetry
Colorimetry is the science to describe physically the human color perception. The wavelength range 380 nm - 780 nm is visible to humans and detected by three different photoreceptors. Many Reptiles see the range 350 nm - 800 nm and have an additional UV photoreceptor in their retina.
Whereas a spectrometer measures the intensity in every tiny wavelength interval resulting in thousands of individual intensities, the human eye only measures three intensities detected by the three cones. The same is true for the reptile eye with usually three or four photoreceptors. Effectively the detailled spectrum displayed above reduces to a much compacter bar graph displayed below. The photoreceptor sensitivites from these L-Cone, M-Cone, S-Cone, and U-Cone are used, they are chosen as an average of measured reptile photoreceptor sensitivity curves. The bar graph also shows as reference the intensity seen by the three or four photoreceptors for average sunlight (id 1).
From these three numbers the colour coordinate and the correlated colour temperature for humans are calculated using the CIE standard method. I adapted this concept to a "3 cone reptile (M,S,U)" and a "4 cone reptile (L,M,S,U)". I am sure, that this adaption to other colour spaces makes sense mathematically and this is also done in scientific research regarding colour vision of animals, however I have not seen calculation of colour temperatures for other animals in the scientific literature. Even if it is hypothetical, at least this shows, how arbitrary the colour temperature is, and that the colour temperature calculated for humans does not apply to reptiles. The colour spaces also show the colour coordinates of different phases of daylight ((ids 1, 338 – 451, 511 – 513 ), indicated by crosses, coloured in the appriximate colour perceived by a human.
| Human (CIE) | 3 cone reptile | 4 cone reptile | |
|---|---|---|---|
| Cone Excitation | |||
| Colour Coordinate | ( 0.33 ; 0.35 ) | ( 0.43 ; 0.37 ) | ( 0.3 ; 0.31 ; 0.26 ) |
| CCT | 5400 Kelvin | 4400 Kelvin | 4800 Kelvin |
| distance | 0.031 | 0.033 | |
| colour space | 3-D-graph not implemented yet |
Vitamin D3 Analysis
Vitamin D3 is produced by UVB radiation around 300 nm. 7DHC/ProD3 present in the skin is converted to PreD3 when absorbing an UV photon. PreD3 can be converted back to ProD3, to Lumisterol, or to Tachysterol when absorbing another UV photon or can be converted to Vitamin D3 in a warm environment.
This process prevents any overdose of vitamin D3 from UV radiation with a spectrum similar to sunlight. As a comparison the solar spectra at 20°(id:14) and at 85°(id:21) solar angle are shown.
The ratio of the two solarmeters 6.2 (UVB) and 6.5 (UV index) readings has proven a useful and very simply number to acess the spectral shape in the vitamin-d3-active region.
Effective Irradiances
Effective irradiances are calculated for all ranges, actionspectra and radiometers currently present in this database.
The calculation method is a numerical implementation (Simpson's rule) of the formula
To learn more about calculating effective irradiances and radiometers I recommend this excellent report on UVB meters: Characterizing the Performance of Integral Measuring UV-Meters (pdf).
The numbers in the following tables can also be used to estimate certain (effective) irradiances from radiomer readings. Example: If the database lists
- range: UVB (US) = 13.8 µW/cm²
- radiometer: Solarmeter 6.2 = 19.6 µW/cm²
Ranges
total ( 0 nm - 0 nm) 44500 µW/cm² = 445 W/m² UVC ( 0 nm - 280 nm) 0 µW/cm² = 0 W/m² non-terrestrial ( 0 nm - 290 nm) 0 µW/cm² = 0 W/m² total2 ( 250 nm - 880 nm) 44500 µW/cm² = 445 W/m² UVB (EU) ( 280 nm - 315 nm) 41.8 µW/cm² = 0.418 W/m² UVB (US) ( 280 nm - 320 nm) 92.9 µW/cm² = 0.929 W/m² UVA+B ( 280 nm - 380 nm) 2140 µW/cm² = 21.4 W/m² Solar UVB ( 290 nm - 315 nm) 41.8 µW/cm² = 0.418 W/m² UVA D3 regulating ( 315 nm - 335 nm) 381 µW/cm² = 3.81 W/m² UVA (EU) ( 315 nm - 380 nm) 2100 µW/cm² = 21 W/m² UVA2 (medical definition) ( 320 nm - 340 nm) 472 µW/cm² = 4.72 W/m² UVA (US) ( 320 nm - 380 nm) 2050 µW/cm² = 20.5 W/m² UVA1 (variant) ( 335 nm - 380 nm) 1720 µW/cm² = 17.2 W/m² UVA1 (medical) ( 340 nm - 400 nm) 2680 µW/cm² = 26.8 W/m² vis. UVA ( 350 nm - 380 nm) 1270 µW/cm² = 12.7 W/m² VIS Rep3 ( 350 nm - 600 nm) 26000 µW/cm² = 260 W/m² VIS Rep4 ( 350 nm - 700 nm) 37300 µW/cm² = 373 W/m² purple ( 380 nm - 420 nm) 2810 µW/cm² = 28.1 W/m² VIS ( 380 nm - 780 nm) 42300 µW/cm² = 423 W/m² VIS2 ( 400 nm - 680 nm) 32900 µW/cm² = 329 W/m² PAR ( 400 nm - 700 nm) 34900 µW/cm² = 349 W/m² tmp ( 400 nm - 1100 nm) 41200 µW/cm² = 412 W/m² blue ( 420 nm - 490 nm) 8140 µW/cm² = 81.4 W/m² green ( 490 nm - 575 nm) 10800 µW/cm² = 108 W/m² yellow ( 575 nm - 585 nm) 1240 µW/cm² = 12.4 W/m² orange ( 585 nm - 650 nm) 7710 µW/cm² = 77.1 W/m² red ( 650 nm - 780 nm) 11600 µW/cm² = 116 W/m² IRA ( 700 nm - 1400 nm) 6300 µW/cm² = 63 W/m² IR2 ( 720 nm - 1100 nm) 4350 µW/cm² = 43.5 W/m² IRB ( 1400 nm - 3000 nm) 0 µW/cm² = 0 W/m²
Actionspectra
Erythema 2.49 UV-Index Pyrimidine dimerization of DNA 33.9 µW/cm² Photoceratitis 2.9 µW/cm² Photoconjunctivitis 0.0258 µW/cm² DNA Damage 0.0896 Vitamin D3 8.8 µW/cm² Photosynthesis 24700 µW/cm² Luminosity 96000 lx Human L-Cone 14400 µW/cm² Human M-Cone 11900 µW/cm² Human S-Cone 6570 µW/cm² CIE X 12800 µW/cm² CIE Y 13300 µW/cm² CIE Z 12300 µW/cm² PAR 165000000 mol photons Extinction preD3 101 e-3*m²/mol Extinction Tachysterol 385 e-3*m²/mol Exctincition PreD3 57800 m²/mol Extinction Lumisterol 4.9 m²/mol Exctincition Tachysterol 715000 m²/mol Extinction 7DHC 2.08 m²/mol L-Cone 12300 µW/cm² M-Cone 12600 µW/cm² S-Cone 10600 µW/cm² U-Cone 5740 µW/cm² UVR - ICNIRP 2004 1.43 Rel Biol Eff Melatonin Supression 10200 µW/cm² Blue Light Hazard 7520 µW/cm² (78.3 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 9.49 µW/cm² Lumen Reptil 97100 "pseudo-lx" Vitamin D3 Degradation 20.7 µW/cm² Actinic UV 1.43 µW/cm² (0.149 mW/klm) Exctincition Lumisterol 10300 m²/mol Exctincition 7DHC 3640 m²/mol Exctincition Toxisterols 15500 m²/mol
Broadbandmeters
Solarmeter 6.2 (UVB, pre 2010) 154 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 2.96 Leybold UVB 95.1 µW/cm² Leybold UVA 1560 µW/cm² Leybold UVC 0 µW/cm² DeltaOhm UVB 410 µW/cm² DeltaOhm UVC 36.1 µW/cm² Vernier UVB 22.2 µW/cm² Vernier UVA 1260 µW/cm² Gröbel UVA 1720 µW/cm² Gröbel UVB 40.2 µW/cm² Gröbel UVC -0.0243 µW/cm² Luxmeter 97100 lx Solarmeter 6.4 (D3) 9.25 IU/min UVX-31 496 µW/cm² IL UVB 0.0773 µW/cm² IL UVA 1830 µW/cm² Solarmeter 6.5 (UVI, post 2010) 2.61 UV-Index Solarmeter 6.2 (UVB, post 2010) 116 µW/cm² (Solarmeter Ratio = 44.5) Solarmeter AlGaN 6.5 UVI sensor 40.6 UV Index GenUV 7.1 UV-Index 3.02 UV-Index Solarmeter 10.0 (Global Power) (manuf.) 486 W/m² Solarmeter 4.0 (UVA) 31.2 mW/cm² LS122 (manuf.) 0 W/m² ISM400 (first guess) 382 W/m² LS122 (assumption) 17.6 W/m² ISM400_new 333 W/m² Solarmeter 10.0 (Global Power) (assumption) 472 W/m²