Single-scattering albedo is the ratio of scattering efficiency to total extinction efficiency (which is also termed "attenuance", a sum of scattering and absorption). Most often it is defined for small-particle scattering of
electromagnetic waves
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ran ...
. Single-scattering albedo is unitless, and a value of unity implies that all particle extinction is due to scattering; conversely, a single-scattering albedo of zero implies that all extinction is due to absorption.
For spherical particles, one can calculate single-scattering albedo from
Mie theory
In electromagnetism, the Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The sol ...
and knowledge of bulk properties of material such as
refractive index
In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...
. For non-spherical particles one could use
discrete dipole approximation
Discrete dipole approximation (DDA), also known as coupled dipole approximation, is a method for computing scattering of radiation by particles of arbitrary shape and by periodic structures. Given a target of arbitrary geometry, one seeks to calcul ...
or other methods of
computational electromagnetics. The albedo of particles of shapes that are easily parameterized in non-standard coordinate systems may be determined through solutions of Maxwell's equation analogs in such coordinate systems. Scattering albedo equations have yet to be determined in elliptical, toroidal, conical, and many others. Derivation and solutions to such equations is a field of ongoing research.
See also
*
Light scattering by particles
Light scattering by particles is the process by which small particles (e.g. ice crystals, dust, atmospheric particulates, cosmic dust, and blood cells) light scattering, scatter light causing optical phenomena such as the Rayleigh scattering, blue ...
*
Albedo
Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
References
*H. C. van de Hulst: ''Light scattering by small particles'', New York, Dover, 1981.
*C. F. Bohren, D. R. Huffmann: ''Absorption and scattering of light by small particles''. New York, Wiley-Interscience, 1983.
Scattering, absorption and radiative transfer (optics)
Atmospheric radiation
Aerosol measurement
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