atmospheric duct


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atmospheric duct

[¦at·mə¦sfir·ik ′dəkt]
(geophysics)
A stratum of the troposphere within which the refractive index varies so as to confine within the limits of the stratum the propagation of an abnormally large proportion of any radiation of sufficiently high frequency, as in a mirage.
References in periodicals archive ?
When radio waves propagate inside an atmospheric duct, the duct may be thought of as a "leaky waveguide.
Sixun, 2012: Estimation of atmospheric duct structure using radar sea clutter.
Atmospheric duct can change the electromagnetic wave propagation path and effective coverage areas, as it is formed in an anomalous atmospheric refractivity structure.
The statistical results for atmospheric duct parameters using synthetic data are shown in Table 1.
Atmospheric duct is a type of abnormal atmosphere structure above maritime boundary layer, caused by the abrupt changes in the vertical atmospheric temperature and humidity profiles above the sea surface [1].
In the atmospheric duct environment, the electromagnetic wave will be trapped into an electromagnetic duct layer, and it can give rise to the over the horizon propagation phenomenon and form the radar detection shadow zone.
Chen, 2013: Statistical estimations of atmospheric duct over the South China Sea and the tropical eastern Indian Ocean.
In the lower MABL, atmospheric ducts frequently occur, which can result in nonstandard electromagnetic propagation of radar signals and wireless communications.
Gong, "Modeling on multieigenpath channel in marine atmospheric duct," Radio Sci.
Three typical types of atmospheric ducts exist: evaporation, surface-based, and elevated ducts [20, 21].
Modeling low elevation GPS signal propagation in maritime atmospheric ducts," Journal of Atmospheric and Solar-Terrestrial Physics, Vol.

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