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The brightness distribution of the overcast sky when the ground is snow‐covered
Author(s) -
Petherbridge P.
Publication year - 1955
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49708134919
Subject(s) - overcast , brightness , sky , zenith , snow , environmental science , sky brightness , albedo (alchemy) , atmospheric sciences , meteorology , remote sensing , geology , physics , optics , art , performance art , art history
Measurements have been made of the brightness distribution of a densely overcast sky when the ground was covered with snow. The distribution proved to be moze uniform than has been reported for normal ground conditions. The distribution was found to be somewhat asymmetric, which may have been due to differences in cloud thickness or to the local influence of inter‐reflections between the base of the cloud and the ground below. The averaged data were found to be represented with reasonable accuracy by the empirical formula: B θ = 1/2 B Z (1 + cos θ) where B θ = brightness of the sky at zenith angle θ and B Z = brightness of the sky at the zenith. The reflection factor of the snow was measured and found to be 80 per cent.