visual range

(Or daytime visual range.) The distance, under daylight conditions, at which the apparent contrast between a specified type of target and its background becomes just equal to the threshold contrast of an observer; to be distinguished from the night visual range.

The visual range is a function of the atmospheric extinction coefficient, the albedo and visual angle of the target, and the observer's threshold contrast at the moment of observation. Only in the so-called meteorological range does one have a visibility figure dependent only upon the extinction coefficient.
See visual-range formula;
compare visibility.
Middleton, W. E. K. 1952. Vision through the Atmosphere. 104–122.
Johnson, J. C. 1954. Physical Meteorology. 79–90.

1. The product of a distance and another parameter.

1. A gaseous envelope gravitationally bound to a celestial body (e.g., a planet, its satellite, or a star).

1. The study of the physics, chemistry, and dynamics of the earth's atmosphere, including the related effects at the air–earth boundary over both land and the oceans. Fundamental topics include the composition, structure, and motion of the atmosphere. The goals ascribed to meteorology are the complete understanding and accurate prediction of atmospheric phenomena.