Extinction cross section

From Glossary of Meteorology

extinction cross section

(Also called attenuation cross section, especially for radar and radio wave propagation.) The area that, when multiplied by the irradiance of electromagnetic waves incident on an object, gives the total radiant flux scattered and absorbed by the object.

Customary usage in radar describes the attenuation cross section as the area that, when multiplied by the power density of incident plane-wave radiation, gives the power removed from the beam by absorption and scattering. For a propagation medium consisting of a dispersion of scattering and absorbing objects, the volume extinction coefficient (m2m-3 or m-1) at a given location in the medium is the sum of the extinction cross sections of all the objects in a unit volume centered at the location.
Compare scattering cross section, absorption cross section.