Attenuation: Difference between revisions
From Glossary of Meteorology
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#<div class="definition"><div class="short_definition">(''Also called'' [[extinction]], especially in reference to optical frequencies.) A general term used to denote a decrease in [[signal strength]] in transmission from one point to another.</div><br/> <div class="paragraph">For the propagation of [[electromagnetic waves]] through a medium, attenuation is caused by [[absorption]] and [[scattering]]. The volume [[attenuation coefficient]] (m<sup> | #<div class="definition"><div class="short_definition">(''Also called'' [[extinction]], especially in reference to optical frequencies.) A general term used to denote a decrease in [[signal strength]] in transmission from one point to another.</div><br/> <div class="paragraph">For the propagation of [[electromagnetic waves]] through a medium, attenuation is caused by [[absorption]] and [[scattering]]. The volume [[attenuation coefficient]] (m<sup>−1</sup>) of such a medium is the fractional reduction of [[radiance]] per unit pathlength. In [[radar]] usage, the [[specific attenuation]] is the fractional reduction in [[power density]] per unit pathlength as plane-wave [[radiation]] propagates through a medium, usually expressed in decibels per kilometer. Attenuation ordinarily does not refer to the inverse-square falloff of [[irradiance]] or power density with [[range]] that is simply a consequence of [[beam]] divergence. <br/>''See'' [[extinction coefficient]].</div><br/> </div> | ||
#<div class="definition"><div class="short_definition">The [[scattering]] and [[absorption]] of [[radiant energy]] by clouds or the [[atmosphere]] that decreases the [[radiation]] received by satellite sensors.</div><br/> </div> | #<div class="definition"><div class="short_definition">The [[scattering]] and [[absorption]] of [[radiant energy]] by clouds or the [[atmosphere]] that decreases the [[radiation]] received by satellite sensors.</div><br/> </div> | ||
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Latest revision as of 11:04, 9 April 2018
attenuation
- (Also called extinction, especially in reference to optical frequencies.) A general term used to denote a decrease in signal strength in transmission from one point to another.
For the propagation of electromagnetic waves through a medium, attenuation is caused by absorption and scattering. The volume attenuation coefficient (m−1) of such a medium is the fractional reduction of radiance per unit pathlength. In radar usage, the specific attenuation is the fractional reduction in power density per unit pathlength as plane-wave radiation propagates through a medium, usually expressed in decibels per kilometer. Attenuation ordinarily does not refer to the inverse-square falloff of irradiance or power density with range that is simply a consequence of beam divergence.
See extinction coefficient.
- The scattering and absorption of radiant energy by clouds or the atmosphere that decreases the radiation received by satellite sensors.