Equivalent reflectivity factor: Difference between revisions
From Glossary of Meteorology
(Created page with " {{TermHeader}} {{TermSearch}} <div class="termentry"> <div class="term"> == equivalent reflectivity factor == </div> <div class="definition"><div class="short_definiti...") |
m (Rewrite with Template:Term and clean up) |
||
| Line 1: | Line 1: | ||
{{Term | |||
|Display title=equivalent reflectivity factor | |||
{{ | |Definitions={{Definition | ||
|Num=1 | |||
|Meaning= The [[radar reflectivity factor]] of a [[target]] consisting of water drops small compared with the [[radar]] wavelength, which would produce the same [[reflectivity]] as that of a target with unknown properties. | |||
|Explanation=Mathematically, the equivalent [[radar reflectivity factor]], ''Z''<sub>''e''</sub>, of a given target is defined by <blockquote>[[File:ams2001glos-Ee57.gif|link=|center|ams2001glos-Ee57]]</blockquote> where η is the reflectivity of the target, λ is the radar [[wavelength]], and 0.93 is the [[dielectric factor]] appropriate for water. This definition is based on the [[Rayleigh scattering]] approximation, which requires that the water drops have diameters no larger than about one-tenth the radar wavelength. For targets consisting of sufficiently small water drops, it follows from the definition that the reflectivity factor, ''Z'', and ''Z''<sub>''e''</sub> are equivalent. But if the composition and sizes of the [[particles]] are unknown, it is appropriate to regard the reflectivity factor that is determined from the measured reflectivity as ''Z''<sub>''e''</sub>. <br/>''See'' [[radar equation]]. | |||
}} | |||
}} | |||
Latest revision as of 08:14, 29 March 2024
The radar reflectivity factor of a target consisting of water drops small compared with the radar wavelength, which would produce the same reflectivity as that of a target with unknown properties.
Mathematically, the equivalent radar reflectivity factor, Ze, of a given target is defined by
See radar equation.
where η is the reflectivity of the target, λ is the radar wavelength, and 0.93 is the dielectric factor appropriate for water. This definition is based on the Rayleigh scattering approximation, which requires that the water drops have diameters no larger than about one-tenth the radar wavelength. For targets consisting of sufficiently small water drops, it follows from the definition that the reflectivity factor, Z, and Ze are equivalent. But if the composition and sizes of the particles are unknown, it is appropriate to regard the reflectivity factor that is determined from the measured reflectivity as Ze.
See radar equation.
