Sunlight just before sunset 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 33: 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.
WARNING: The measurement range (350 - 800 nm) is not sufficient for this evaluation! Data is only available in the range 300 - 589 nm. Results are shown anyway but should be ignored by anyone except experts.
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 | ( 0.3 ; 0.51 ) | ( 0.69 ; 0.22 ) | ( 0.41 ; 0.41 ; 0.13 ) |
| CCT | 6300 Kelvin | 2200 Kelvin | 3700 Kelvin |
| distance | 0.015 | 0.13 | |
| 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) 87 µW/cm² = 0.87 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) 87 µW/cm² = 0.87 W/m² UVB (EU) ( 280 nm - 315 nm) 0.726 µW/cm² = 0.00726 W/m² UVB (US) ( 280 nm - 320 nm) 0.974 µW/cm² = 0.00974 W/m² UVA+B ( 280 nm - 380 nm) 3.94 µW/cm² = 0.0394 W/m² Solar UVB ( 290 nm - 315 nm) 0.726 µW/cm² = 0.00726 W/m² UVA D3 regulating ( 315 nm - 335 nm) 0.99 µW/cm² = 0.0099 W/m² UVA (EU) ( 315 nm - 380 nm) 3.22 µW/cm² = 0.0322 W/m² UVA2 (medical definition) ( 320 nm - 340 nm) 0.99 µW/cm² = 0.0099 W/m² UVA (US) ( 320 nm - 380 nm) 2.97 µW/cm² = 0.0297 W/m² UVA1 (variant) ( 335 nm - 380 nm) 2.23 µW/cm² = 0.0223 W/m² UVA1 (medical) ( 340 nm - 400 nm) 2.97 µW/cm² = 0.0297 W/m² vis. UVA ( 350 nm - 380 nm) 1.49 µW/cm² = 0.0149 W/m² VIS Rep3 ( 350 nm - 600 nm) 84.5 µW/cm² = 0.845 W/m² VIS Rep4 ( 350 nm - 700 nm) 84.5 µW/cm² = 0.845 W/m² purple ( 380 nm - 420 nm) 2.13 µW/cm² = 0.0213 W/m² VIS ( 380 nm - 780 nm) 83 µW/cm² = 0.83 W/m² VIS2 ( 400 nm - 680 nm) 82 µW/cm² = 0.82 W/m² PAR ( 400 nm - 700 nm) 82 µW/cm² = 0.82 W/m² tmp ( 400 nm - 1100 nm) 82 µW/cm² = 0.82 W/m² blue ( 420 nm - 490 nm) 13.7 µW/cm² = 0.137 W/m² green ( 490 nm - 575 nm) 54.1 µW/cm² = 0.541 W/m² yellow ( 575 nm - 585 nm) 9.27 µW/cm² = 0.0927 W/m² orange ( 585 nm - 650 nm) 3.86 µW/cm² = 0.0386 W/m² red ( 650 nm - 780 nm) 0 µW/cm² = 0 W/m² IRA ( 700 nm - 1400 nm) 0 µW/cm² = 0 W/m² IR2 ( 720 nm - 1100 nm) 0 µW/cm² = 0 W/m² IRB ( 1400 nm - 3000 nm) 0 µW/cm² = 0 W/m²
Actionspectra
Erythema 0.0556 UV-Index Pyrimidine dimerization of DNA 0.534 µW/cm² Photoceratitis 0.0846 µW/cm² Photoconjunctivitis 0.00138 µW/cm² DNA Damage 0.00458 Vitamin D3 0.28 µW/cm² Photosynthesis 45.1 µW/cm² Luminosity 388 lx Human L-Cone 54.9 µW/cm² Human M-Cone 54.4 µW/cm² Human S-Cone 10.5 µW/cm² CIE X 32.5 µW/cm² CIE Y 55.5 µW/cm² CIE Z 20.9 µW/cm² PAR 362000 mol photons Extinction preD3 1.29 e-3*m²/mol Extinction Tachysterol 4.32 e-3*m²/mol Exctincition PreD3 586 m²/mol Extinction Lumisterol 0.238 m²/mol Exctincition Tachysterol 5830 m²/mol Extinction 7DHC 0.14 m²/mol L-Cone 43.2 µW/cm² M-Cone 43.7 µW/cm² S-Cone 14 µW/cm² U-Cone 5.19 µW/cm² UVR - ICNIRP 2004 0.0454 Rel Biol Eff Melatonin Supression 21 µW/cm² Blue Light Hazard 11.7 µW/cm² (30.2 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 0.32 µW/cm² Lumen Reptil 275 "pseudo-lx" Vitamin D3 Degradation 0.209 µW/cm² Actinic UV 0.0437 µW/cm² (1.13 mW/klm) Exctincition Lumisterol 329 m²/mol Exctincition 7DHC 186 m²/mol Exctincition Toxisterols 83.3 m²/mol
Broadbandmeters
Solarmeter 6.2 (UVB, pre 2010) 1.15 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 0.0787 Leybold UVB 0.887 µW/cm² Leybold UVA 2.17 µW/cm² Leybold UVC 0 µW/cm² DeltaOhm UVB 1.55 µW/cm² DeltaOhm UVC 0.208 µW/cm² Vernier UVB 0.502 µW/cm² Vernier UVA 2.33 µW/cm² Gröbel UVA 2.67 µW/cm² Gröbel UVB 0.533 µW/cm² Gröbel UVC 0.000374 µW/cm² Luxmeter 428 lx Solarmeter 6.4 (D3) 0.246 IU/min UVX-31 1.76 µW/cm² IL UVB 0.000499 µW/cm² IL UVA 2.55 µW/cm² Solarmeter 6.5 (UVI, post 2010) 0.0636 UV-Index Solarmeter 6.2 (UVB, post 2010) 0.694 µW/cm² (Solarmeter Ratio = 10.9) Solarmeter AlGaN 6.5 UVI sensor 0.666 UV Index GenUV 7.1 UV-Index 0.034 UV-Index Solarmeter 10.0 (Global Power) (manuf.) 0.852 W/m² Solarmeter 4.0 (UVA) 0.0394 mW/cm² LS122 (manuf.) 0 W/m² ISM400 (first guess) 0.524 W/m² LS122 (assumption) 0.0266 W/m² ISM400_new 0.39 W/m² Solarmeter 10.0 (Global Power) (assumption) 0.83 W/m²