Prototype geophysical vortex structures via large-scale statistical theory

Mark T. Dibattista, Andrew J. Majda, Bruce Turkington

Research output: Contribution to journalArticlepeer-review

Abstract

Suitable vortex dipole pairs (modons) in eastward flow as well as monopole vortices in β-plane channel flow are characterized systematically in appropriate parameter regimes as the most-probable large-scale mean-field states predicted from a recent statistical theory (Turkington, 1998); this theory utilizes only a few conserved quantities involving energy, circulation, potential vorticity extrema, and the mean potential vorticity magnitude. The large-scale coherent structures emerge systematically from the statistical theory through maximization of a suitable coarse-grained entropy functional subject to the constraints imposed by these few conserved quantities. An accurate numerical procedure is developed here to study these states. For dilute PV theory, the most-probable large-scale coherent structures in eastward mean flows with nonzero β-effect are either dipolar vortex streets or zonal shear flows. The transition boundary of the predicted large-scale coherent structures between coherent vortices and zonal shear flows is related to a generalized Rhines' scale as the β-effect and energy are varied. The role of symmetry groups in the potential vorticity is emphasized here. In particular, in some parameter regimes the most-probable state within a given symmetry group of dipole pairs is not necessarily the most-probable large-scale coherent structure when the symmetry is broken.

Original languageEnglish (US)
Pages (from-to)235-283
Number of pages49
JournalGeophysical and Astrophysical Fluid Dynamics
Volume89
Issue number3-4
DOIs
StatePublished - 1998

Keywords

  • Coherent structure
  • Dipole vortices
  • Eastward flow
  • Statistical theory

ASJC Scopus subject areas

  • Computational Mechanics
  • Astronomy and Astrophysics
  • Geophysics
  • Mechanics of Materials
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Prototype geophysical vortex structures via large-scale statistical theory'. Together they form a unique fingerprint.

Cite this