Rozkład luminancji nieba (CIE)
15 standardowych typów nieba wg CIE S 011/E:2003
Dane
Typ nieba
1 — CIE Standard Overcast
2 — Overcast, steeper gradation
3 — Overcast, azimuthal uniformity
4 — Overcast, slight brightening near sun
5 — Uniform luminance
6 — Partly cloudy, no zenith gradation
7 — Partly cloudy, brighter circumsolar
8 — Partly cloudy, distinct solar corona
9 — Partly cloudy, obscured sun
10 — Partly cloudy, brighter circumsolar
11 — White-blue, distinct solar corona
12 — CIE Standard Clear Sky
13 — Clear sky, polluted
14 — Cloudless turbid, broad corona
15 — White-blue turbid, broad corona
Wyniki
Wzór
L_p / L_z = [ f(χ) · φ(Z) ] / [ f(Z_s) · φ(0) ]
f(χ) = 1 + c·(e^(d·χ) − e^(d·π/2)) + e·cos²(χ)
φ(Z) = 1 + a · exp(b / cos Z)
cos χ = cos Z_s · cos Z + sin Z_s · sin Z · cos|A − A_s|