Zonal Flow as Pattern Formation: Merging Jets and the Ultimate Jet Length Scale
Authors: Jeffrey B. Parker and John A. Krommes
Abstract: Zonal flows are well known to arise spontaneously out of turbulence. It is shown that for statisti-
cally averaged equations of quasigeostrophic turbulence on a beta plane, zonal flows and inhomoge-
neous turbulence fit into the framework of pattern formation. There are many implications. First,
the zonal flow wavelength is not unique. Indeed, in an idealized, infinite system, any wavelength
within a certain continuous band corresponds to a solution. Second, of these wavelengths, only those
within a smaller subband are linearly stable. Unstable wavelengths must evolve to reach a stable
wavelength; this process manifests as merging jets.
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Submitted to: Physical Review Letters (January 2013)
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