absorption coefficient
From Glossary of Meteorology
A measure of the extinction due to absorption of monochromatic radiation as it traverses a medium.
Usually expressed as a volume absorption coefficient, kv, with units of reciprocal length (i.e., area per unit volume), but also as a mass absorption coefficient, km, with units of area per unit mass. The two are related by kv = ρkm, where ρ is the density of the absorber.
See also absorption optical thickness.
