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 ?
As well as making flights bumpier and less comfortable, this could also increase the risk of injury to passengers and crew"-especially in winter when Northern Hemisphere clear-air turbulence is thought to be most intense.
A: Clear-air turbulence is often referred to as `rough air' or `air pockets', and is a safety hazard for aircraft, as it cannot be seen, but definitely can be felt.
28 incident in which clear-air turbulence jarred a Boeing 747-100, killing one woman and injuring dozens of other passengers.
There he managed projects involving refractive-index turbulence and clear-air turbulence in the free atmosphere.
At NASA's Langley Research Center, Zuckerwar is investigating how to use infrasound data to warn airplane pilots of clear-air turbulence.
A United spokeswoman said the Boeing 747 encountered ``severe clear-air turbulence,'' unanticipated rockiness that develops when there are no storms visible.
Since lee-side troughing is strongly associated with clear-air turbulence (CAT), it's always a good idea to sift carefully through the turbulence forecasts and PIREPs in this kind of pattern.
Supercell thunderstorms, on the other hand, often produce dangerous clear-air turbulence downwind that's essentially invisible.