ناپایداری ِ فشارشیبی
Fr.: instabilité barocline
1) A type of instability occurring within a rapidly → rotating star
where non-axisymmetric motions can separate surfaces of constant pressure from
→ equipotential surfaces.
2) A hydrodynamic instability associated with a baroclinic layer of the atmosphere. It
arises from temperature variation along the pressure surfaces. Baroclinic instability is
associated with the vertical → shear
of the mean flow, which is related to the
horizontal temperature gradient by the thermal wind equation. Instabilities in a
baroclinic region grow by converting potential energy associated with the mean horizontal
temperature gradient into kinetic energy through ascending warm air and descending cold air
(Rasmussen & Turner (eds.), Polar Lows, Cambridge Univ. Press, 2003).
→ baroclinic; → instability.