Turbulence in the middle atmosphere: A review
Abstract
The stratosphere is characterized for being highly statically stable. lt takes considerable energy to interchange parcels of air from different altitudes; thus, turbulence is normally inhibited, Wind shears of the order of 40 m/sec per kilometer are necessary to overcome the stabilizing effect of negative buoyancy if turbulence is to occur. Shears close to these values do exist in narrow but horizontally extensive layers as a consequence of internal gravity waves and the twodimensional (horizontal) turbulent character of mesoscale stratospheric winds. Shorter wavelength waves, superimposed on these shears, make the local shear exceed the threshold (Richardson number < 0.25) for KelvinHelmholtz instabilities to occur and in turn, to break into turbulence. In addition, the shear of these waves may be enhanced by a nonlinear unstable amplification of those gravity waves whose phase velocity matches the local wind velocity. As a consequence, turbulence in the stratosphere occurs intermittently, in extensive layers from ten to a few hundred kilometers in extent, and only a few ten to a few hundred meters in thickness.
Description
Date
1980
Keywords
Stratosphere , Turbulence , Stratospheric winds
Citation
Woodman, R. F. (1980). Turbulence in the middle atmosphere: A review.
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