Symmetric instability
From Glossary of Meteorology
Revision as of 18:03, 25 April 2012 by imported>Perlwikibot
symmetric instability
Similar to inertial instability but caused by the imbalance between pressure gradient and inertial forces for infinitesimal disturbances that meridionally displace fluid along isentropes (in the atmosphere) or isopycnals (in the ocean).
For geostrophic motion in the Northern Hemisphere, symmetric instability may occur only if the potential vorticity is negative.