Directional sky luminance versus cloud cover and solar position

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Solar Energy (Journal of Solar Energy Science and Engineering); (USA)

DOI:https://doi.org/10.1016/0038-092X(91)90102-3· OSTI ID:5850932

Harrison, A W ^[1]

---

1. Univ. of Calgary, Alberta (Canada)

Measurements of sky luminance at 121 equally spaced points ({theta},{phi}) over the sky dome under clear, partly cloudy and overcast skies have led to the following analytical expression for normalized sky luminance L{sub v}({theta},{phi},{theta}*,C) = CL {sub vc}{sup 0}({theta},{phi},{theta}*) + (1 {minus} C)L{sub vc}{sup c}({theta},{phi},{theta}*) L{sub vc}{sup 0}({theta},{phi},{theta}I) = 0.40 + 0.21{theta}* + 0.27 cos {theta} + 1.45 e{sup {minus}2.4l{psi}}L{sub vc}({theta},{phi},{theta}*) = (1.28 + 147e{sup {minus}11.1{phi}} + 4.28 cos{sup 2}{phi} cos{theta}*)*(1 {minus} e{sup {minus}0.42sec{theta}})*(1{minus}e{sup {minus}0.67sec{theta}}) where {theta} = sky point zenith angle, {phi} = sky point azimuth angle, {theta}* = solar zenith angle, {phi} = scattering angle between sky, and sun direction and C = opaque cloud cover ({theta}* and {phi} in radians).

• OSTI ID: 5850932
• Journal Information: Solar Energy (Journal of Solar Energy Science and Engineering); (USA), Journal Name: Solar Energy (Journal of Solar Energy Science and Engineering); (USA) Vol. 46:1; ISSN SRENA; ISSN 0038-092X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140100* -- Solar Energy-- Resources & Availability
CLOUD COVER
CORRELATIONS
DATA
DIFFUSE SOLAR RADIATION
DIRECT SOLAR RADIATION
EQUATIONS
INFORMATION
INSOLATION
MAIN SEQUENCE STARS
MAPS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
ORIENTATION
RADIATIONS
SOLAR FLUX
SOLAR RADIATION
STARS
STELLAR RADIATION
SUN