clear-air turbulence


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clear-air turbulence

[‚klir ′er ′tərb·yə·ləns]
(meteorology)
A meteorological phenomenon occurring in the upper troposphere and lower stratosphere, in which high-speed aircraft are subject to violent updrafts and downdrafts. Abbreviated CAT.

clear-air turbulence (CAT)

clear-air turbulence (CAT)click for a larger image
Turbulence in clear air, which is not a result of the presence of clouds or thermal heating of the ground. It appears to arise from an internal function of the atmosphere resulting from wind shear and perhaps temperature shear. Clear-air turbulence is generally associated with jet streams, although it can occur at lower levels and outside the jet streams. Clear air turbulence may also be experienced above the mountain waves and thunderstorms.
References in periodicals archive ?
Currently, computer models can forecast clear-air turbulence, but there's no direct detection device.
Kate pointed out many uses, including detecting clear-air turbulence and avalanches and monitoring atmospheric explosions.
A United spokeswoman said the Boeing 747 encountered ``severe clear-air turbulence,'' unanticipated rockiness that develops when there are no storms visible.