Difference between revisions of "Extinction Coefficient"
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Extinction Coefficient
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In meteorology, a measure of the space rate of diminution, or extinction,
of any transmitted light; thus, it is the attenuation
coefficient
applied to visible
radiation. The extinction coefficient Missing Image:img src="SP7-e_files/epsilonsm.gif" is
identified as
illuminance (luminous flux density) at the selected point in space,
I0 is the illuminance at the light source; and x is
the distance from the source.
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When so used, the extinction coefficient equals the sum of the medium's
absorption coefficient and scattering coefficient, each computed as a weighted
average over all wavelengths in the visible spectrum. As long as scattering
effects are primary, as in the lower atmosphere, the value of the extinction
coefficient is a function of the particle size of atmospheric suspensoids. It
varies in order of magnitude from 10 per kilometer with very low visibility to
0.01 per kilometer in very clear air.
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References
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use
