Skylight 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 35: 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 | ( 0.26 ; 0.28 ) | ( 0.36 ; 0.39 ) | ( 0.18 ; 0.29 ; 0.32 ) |
| CCT | 14000 Kelvin | 5800 Kelvin | 7400 Kelvin |
| distance | 0.05 | 0.075 | |
| 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) 811 µW/cm² = 8.11 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) 811 µW/cm² = 8.11 W/m² UVB (EU) ( 280 nm - 315 nm) 0.0284 µW/cm² = 0.000284 W/m² UVB (US) ( 280 nm - 320 nm) 0.176 µW/cm² = 0.00176 W/m² UVA+B ( 280 nm - 380 nm) 75.4 µW/cm² = 0.754 W/m² Solar UVB ( 290 nm - 315 nm) 0.0284 µW/cm² = 0.000284 W/m² UVA D3 regulating ( 315 nm - 335 nm) 7.32 µW/cm² = 0.0732 W/m² UVA (EU) ( 315 nm - 380 nm) 75.4 µW/cm² = 0.754 W/m² UVA2 (medical definition) ( 320 nm - 340 nm) 12.9 µW/cm² = 0.129 W/m² UVA (US) ( 320 nm - 380 nm) 75.3 µW/cm² = 0.753 W/m² UVA1 (variant) ( 335 nm - 380 nm) 68.1 µW/cm² = 0.681 W/m² UVA1 (medical) ( 340 nm - 400 nm) 100 µW/cm² = 1 W/m² vis. UVA ( 350 nm - 380 nm) 49.6 µW/cm² = 0.496 W/m² VIS Rep3 ( 350 nm - 600 nm) 615 µW/cm² = 6.15 W/m² VIS Rep4 ( 350 nm - 700 nm) 741 µW/cm² = 7.41 W/m² purple ( 380 nm - 420 nm) 94.7 µW/cm² = 0.947 W/m² VIS ( 380 nm - 780 nm) 736 µW/cm² = 7.36 W/m² VIS2 ( 400 nm - 680 nm) 635 µW/cm² = 6.35 W/m² PAR ( 400 nm - 700 nm) 653 µW/cm² = 6.53 W/m² tmp ( 400 nm - 1100 nm) 698 µW/cm² = 6.98 W/m² blue ( 420 nm - 490 nm) 232 µW/cm² = 2.32 W/m² green ( 490 nm - 575 nm) 203 µW/cm² = 2.03 W/m² yellow ( 575 nm - 585 nm) 15.6 µW/cm² = 0.156 W/m² orange ( 585 nm - 650 nm) 90.2 µW/cm² = 0.902 W/m² red ( 650 nm - 780 nm) 101 µW/cm² = 1.01 W/m² IRA ( 700 nm - 1400 nm) 45 µW/cm² = 0.45 W/m² IR2 ( 720 nm - 1100 nm) 27.9 µW/cm² = 0.279 W/m² IRB ( 1400 nm - 3000 nm) 0 µW/cm² = 0 W/m²
Actionspectra
Erythema 0.0232 UV-Index Pyrimidine dimerization of DNA 0.151 µW/cm² Photoceratitis 0.00119 µW/cm² Photoconjunctivitis 0 µW/cm² DNA Damage 0.000116 Vitamin D3 0.0033 µW/cm² Photosynthesis 478 µW/cm² Luminosity 1560 lx Human L-Cone 224 µW/cm² Human M-Cone 212 µW/cm² Human S-Cone 190 µW/cm² CIE X 197 µW/cm² CIE Y 215 µW/cm² CIE Z 350 µW/cm² PAR 2960000 mol photons Extinction preD3 0.397 e-3*m²/mol Extinction Tachysterol 1.87 e-3*m²/mol Exctincition PreD3 682 m²/mol Extinction Lumisterol 0.00038 m²/mol Exctincition Tachysterol 10100 m²/mol Extinction 7DHC 0 m²/mol L-Cone 177 µW/cm² M-Cone 292 µW/cm² S-Cone 319 µW/cm² U-Cone 203 µW/cm² UVR - ICNIRP 2004 0.0154 Rel Biol Eff Melatonin Supression 279 µW/cm² Blue Light Hazard 219 µW/cm² (140 µW/cm² per 1000 lx) CIE 174:2006 PreVit D3 0.00201 µW/cm² Lumen Reptil 2140 "pseudo-lx" Vitamin D3 Degradation 0.142 µW/cm² Actinic UV 0.0154 µW/cm² (0.0986 mW/klm) Exctincition Lumisterol 15.5 m²/mol Exctincition 7DHC 2.1 m²/mol Exctincition Toxisterols 320 m²/mol
Broadbandmeters
Solarmeter 6.2 (UVB, pre 2010) 1.15 µW/cm² Solarmeter 6.5 (UV-Index, pre 2010) 0.012 Leybold UVB 0.531 µW/cm² Leybold UVA 60 µW/cm² Leybold UVC 0 µW/cm² DeltaOhm UVB 8.11 µW/cm² DeltaOhm UVC 0.271 µW/cm² Vernier UVB 0.00941 µW/cm² Vernier UVA 42.8 µW/cm² Gröbel UVA 63.2 µW/cm² Gröbel UVB 0.373 µW/cm² Gröbel UVC -5.97E-5 µW/cm² Luxmeter 1620 lx Solarmeter 6.4 (D3) 0.0374 IU/min UVX-31 11.9 µW/cm² IL UVB 0.00124 µW/cm² IL UVA 69.2 µW/cm² Solarmeter 6.5 (UVI, post 2010) 0.00922 UV-Index Solarmeter 6.2 (UVB, post 2010) 0.931 µW/cm² (Solarmeter Ratio = 101) Solarmeter AlGaN 6.5 UVI sensor 0.0823 UV Index GenUV 7.1 UV-Index 0.0231 UV-Index Solarmeter 10.0 (Global Power) (manuf.) 7.52 W/m² Solarmeter 4.0 (UVA) 1.14 mW/cm² LS122 (manuf.) 0 W/m² ISM400 (first guess) 4.87 W/m² LS122 (assumption) 0.201 W/m² ISM400_new 3.95 W/m² Solarmeter 10.0 (Global Power) (assumption) 6.87 W/m²