Difference between revisions of "Barotropic instability"

From Glossary of Meteorology
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<div class="definition"><div class="short_definition">The [[hydrodynamic instability]] arising from certain distributions of [[vorticity]]  in a two-dimensional nondivergent flow.</div><br/> <div class="paragraph">This is an [[inertial instability]] in that [[kinetic energy]] is the only form of [[energy]] transferred  between [[current]] and [[perturbation]]. The [[variation]] of vorticity in the basic current may be concentrated  in discontinuities of the [[horizontal wind shear]] (to be distinguished from [[Helmholtz  instability]], where the [[velocity]] itself is discontinuous) or may be continuously distributed in a  curved [[velocity profile]]. A well-known necessary condition for barotropic instability is that the  basic state vorticity gradient must have both signs in the domain (i.e., counterpropagating [[Rossby  waves]] must be possible).</div><br/> </div>
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<div class="definition"><div class="short_definition">The [[hydrodynamic instability]] arising from certain distributions of [[vorticity]]  in a two-dimensional nondivergent flow.</div><br/> <div class="paragraph">This is an [[inertial instability]] in that [[kinetic energy]] is the only form of [[energy]] transferred  between [[current]] and [[perturbation]]. The [[variation]] of vorticity in the basic current may be concentrated  in discontinuities of the [[horizontal wind shear]] (to be distinguished from [[Helmholtz instability|Helmholtz  instability]], where the [[velocity]] itself is discontinuous) or may be continuously distributed in a  curved [[velocity profile]]. A well-known necessary condition for barotropic instability is that the  basic state vorticity gradient must have both signs in the domain (i.e., counterpropagating [[Rossby  waves]] must be possible).</div><br/> </div>
 
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Latest revision as of 15:28, 25 April 2012



barotropic instability

The hydrodynamic instability arising from certain distributions of vorticity in a two-dimensional nondivergent flow.

This is an inertial instability in that kinetic energy is the only form of energy transferred between current and perturbation. The variation of vorticity in the basic current may be concentrated in discontinuities of the horizontal wind shear (to be distinguished from Helmholtz instability, where the velocity itself is discontinuous) or may be continuously distributed in a curved velocity profile. A well-known necessary condition for barotropic instability is that the basic state vorticity gradient must have both signs in the domain (i.e., counterpropagating Rossby waves must be possible).