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SUMMARY:The turbulent equilibration of an unstable baroclinic jet - Esler\
 , G (UCL)
DTSTART:20081208T103000Z
DTEND:20081208T110000Z
UID:TALK15601@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:The evolution of an unstable baroclinic jet\, subject to a sma
 ll perturbation\, is examined numerically in a quasi-geostrophic two-layer
  channel model. After a period of initial wave growth\, wave breaking lead
 s to two-dimensional turbulence within each layer\, and to the eventual eq
 uilibration of the flow. The equilibrated flow must satisfy certain constr
 aints\; its total momentum is conserved\, its total energy is bounded and 
 the flow must be realizable via some area preserving (diffusive) rearrange
 ment of the potential vorticity field of the initial flow. A theory is int
 roduced that predicts the equilibrated flow in terms of the initial flow p
 arameters. The idea is that the final state minimizes available potential 
 energy\, subject to constraints on the total momentum and total energy\, a
 nd the further constraint that the potential vorticity changes through a p
 rocess of complete homogenization within well-delineated regions in each l
 ayer. Within a large region of parameter space\, the theory is found to ac
 curately predict the cross-channel structure and strength of the equilibra
 ted jet\, the regions where potential vorticity mixing takes place\, and t
 otal eddy mass (temperature) fluxes.
LOCATION:Seminar Room 1\, Newton Institute
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