| quotient of the sum of the solid angles subtended by clouds and the solid angle 2π sr of the whole sky Note 1 to entry: Observation of total cloud amount is usually recorded in tenths or oktas, where one okta indicates an extent of cloud cover equal to one eighth of the sky. Note 2 to entry: The total cloud amount has unit one. Note 3 to entry: This entry was numbered 845-09-92 in IEC 60050-845:1987.
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