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Topic: Baroclinic Instability

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	Baroclinic Instability - Wikipedia, the free encyclopedia
		Baroclinic Instability is a fluid dynamic instability which helps to understand some important features of the so-called large scale waves in the mid-latitude atmosphere.
		The first accurate theoretical model to include baroclinic instability was the one developed by Jule Charney in 1947.
		Baroclinic instability can be investigated in the laboratory using a rotating, fluid filled annulus.
	en.wikipedia.org /wiki/Baroclinic_Instability (316 words)

	[No title]
		The long wave limit of the baroclinic instability of the associated mean flow (varying only in the vertical) is studied and analytical calculations demonstrate that growth rates of order one cycle per year can be produced, large enough to amplify thermal anomalies in the face of dissipation.
		Motivated by the previous idea that baroclinic instability of the western boundary current region provides the energy source for the oscillations to be maintained against dissipation, we wish to inquire from a more general theoretical ground the character of that instability and evaluate its strength as gauged by the growth rate.
		Although most studies of baroclinic instability choose basic states which consist of zonal flows, the experiments do not suggest this to be a particularly good choice since the predominantly meridional flows along the western boundaries appear to be potentially the most unstable.
	www.ifremer.fr /lpo/thuck/publis/jpo3.html (9335 words)

	Instability - Wikipedia, the free encyclopedia
		Instability in systems is generally characterized by some of the outputs or internal states growing without bounds.
		Fluid instabilities occur in liquids, gases and plasmas, and are often characterised by the shape that form; they are studied in fluid dynamics and magnetohydrodynamics.
		Diocotron instability (similar to, but different to the Kelvin-Helmholtz instability).
	en.wikipedia.org /wiki/Instability (266 words)

	Mesoscale Dynamics
		Relating these observations to the classical theory of baroclinic instability is not immediately obvious, since in the latter, the precise form of the initial condition is not important, and the theory predicts cyclogenesis with a fixed-in-time vertical structure.
		Baroclinicity, while reducing the overall mountain effect, allows the northerlies in the lee to extend further downstream.
		The intensity of rainband activity is correlated with the depth of the tradewind layer and conditional instability.
	www.mmm.ucar.edu /asr95/part-A.html (7616 words)

	Mount Washington Observatory: Glossary of Weather Terms (Site not responding. Last check: 2007-10-18)
		In a baroclinic atmosphere, there is a horizontal temperature gradient and variation with height of the geostrophic wind (thermal wind).
		Baroclinic instability converts potential energy to kinetic energy and is an important mechanism in the global energy balance.
		Baroclinic waves are also referred to as baroclinic cyclones or baroclinic disturbances.
	www.mountwashington.org /glossary/glosb.html (595 words)

	Abstract: Linear Baroclinic Instability (Site not responding. Last check: 2007-10-18)
		The linear wave and baroclinic instability properties of various geostrophic models valid when the Rossby number is small, are investigated.
		The goal is to determine whether these models accurately portray linear baroclinic instability properties in various geophysically relevant parameter regimes, in a highly idealized and limited set of cases.
		The growth rate of baroclinic instability in the planetary geostrophic equations is shown to be generally less than the growth rate of the other models near the deformation radius.
	www.math.nyu.edu /research/shafer/papers/abstract_lin.html (311 words)

	Mixed baroclinic-barotropic instability
		Killworth (1980) performed linear stability analysis of assumed profiles with both two-layer and continuous stratification and found the mixed instability is described by three non-dimensional parameters: the ratio of the horizontal length scale of the shear to the internal deformation radius, the ratio of layer depths, and
		In the simplest case, the energy is drawn from the available potential energy of the heavy upwelled fluid (baroclinic instability) and from the kinetic energy of the mean flow (barotropic instability).
		The equations employed here to study frontal instability are the inviscid shallow-water equations [Barth, 1989a] since the quasi-geostrophic equations do not allow large interface displacements, strong shears or large slopes of the bottom surface.
	www-fpc.stanford.edu /research/insb1/node9.html (628 words)

	[No title]
		Baroclinic instability, a hydrodynamic instability arising from the existence of a meridional temperature gradient, and hence thermal wind, is a well accepted theoretical explanation of cyclogenesis [
		Paralleling the studies of the role of baroclinic instability in cyclone development have been a number of studies that have examined the role of diabatic processes.
		(Barotropic instability is a hydrodynamic wave instability associated with the horizontal shear in a jet-like current, and grows by extracting kinetic energy from the mean flow.) In some cases these modes lead to triple the growth rate of unsheared waves.
	www.agu.org /revgeophys/busing00/node3.html (718 words)

	Baroclinic instability (Site not responding. Last check: 2007-10-18)
		Baroclinic instability produces wave motion due to vertical shear of the basic current in the presence of Coriolis and buoyancy forces.
		The structure of the baroclinic mode depends on the stratification.
		In a stratified fluid, APE is the difference between the sum of internal and potential energy and the minimum value obtained by adiabatic redistribution.
	www-fpc.stanford.edu /research/insb1/node8.html (157 words)

	[No title]
		Baroclinic Instability, cont d.¡ C$ª¨>We typically try to solve instability problems like the Eady model by assuming a time and space dependence like: exp[ik(x-ct)] where c = cr + icim where cr is the phase speed, and cim is the growth rate.
		Grotjahn, R., M. Chen, J. Tribbia, 1994: Linear instability with Ekman and interior friction.
		Grotjahn, R., R. Pederson, J. Tribbia, 1994: Linear instability with Ekman and interior friction.
	www.atmos.umd.edu /~dankd/BLM/BLM2004Notes10.ppt (444 words)

	Harley Hurlburt (Site not responding. Last check: 2007-10-18)
		The models show how the combined effects of baroclinic instability and specific topographic features have a profound influence on 1) the mean path of the Kuroshio just south and east of Japan and 2) on separating the northward flow connecting the Kuroshio and Oyashio/subarctic front from the east coast of Japan.
		The baroclinic instability gives eddy driven deep mean flows that follow the f/h contours of the bottom topography.
		At 1/16° resolution we are discovering the widespread importance of baroclinic instability in allowing bottom topography to steer upper ocean currents.
	sam.ucsd.edu /WOCE/Workshop/Abstracts/hurlburt.html (541 words)

	Polar Low Forecasting (Site not responding. Last check: 2007-10-18)
		Baroclinic instability is associated with vertical shear of the mean flow.
		Baroclinic instabilities grow by converting potential energy associated with the mean horizontal temperature gradient (Holton 1992).
		Barotropic instability is a wave instability associated with the horizontal shear in a jet-like current.
	meted.ucar.edu /norlat/snow/polarlows/print_whole.htm (12195 words)

	[No title]
		The instability associated with the horizontal and vertical shear is called the barotropic and baroclinic instability, respectively.
		(km ¨2 ). In the case of barotropic instability, for a mean flow of (yU > 0, the unstable disturbance will have Fy ( -
		(6.4.9) The instability is called the barotropic instability if the first term (horizontal shear) is dominant, and is called the baroclinic instability if the second term (vertical shear, or horizontal temperature gradient) or the temperature gradient on the top and bottom boundaries is dominant.
	www.aos.wisc.edu /~aos611/611Chapt6.doc (2816 words)

	1999: Journal of the Atmospheric Sciences, 56(11), 1579-1593
		Abstract: The linear wave and baroclinic instability properties of various geostrophic models valid when the Rossby number is small are investigated.
		The models are cast in multilayer form, and the dispersion properties and eigenfunctions of wave modes and baroclinic instabilities produced are found numerically.
		The growth rate of the planetary geostrophic equations diverges at high wavenumbers, but it is shown how this is ameliorated by the presence of the relative vorticity term in the geostrophic potential vorticity equations.
	www.gfdl.noaa.gov /reference/bibliography/1999/kss9901.html (404 words)

	The Observed Life Cycle of a Baroclinic Instability (Site not responding. Last check: 2007-10-18)
		Randel and Stanford have studied the dynamics of these features, demonstrating that the medium-scale waves result from baroclinic excitation and exhibit well-defined life cycles.
		The specific case chosen exhibits a high degree of zonal symmetry, prompting study based upon zonally averaged diagnostics.
		An analysis of the medium-scale wave energetics reveals a well-defined life cycle of baroclinic growth, maturity, and barotropic decay.
	www.physics.iastate.edu /atmos/abs64.html (134 words)

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