Geophysical flows with anisotropic turbulence and dispersive waves: Flows with a β-effect

Boris Galperin, Semion Sukoriansky, Nadejda Dikovskaya

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Geostrophic turbulence is a key paradigm in the current understanding of the large-scale planetary circulations. It implies that a flow is turbulent, rotating, stably stratified, and in near-geostrophic balance. When a small-scale forcing is present, geostrophic turbulence features an inverse energy cascade. When the meridional variation of the Coriolis parameter (or a β-effect) is included, the horizontal flow symmetry breaks down giving rise to the emergence of jet flows. The presence of a large-scale drag ensures that the flow attains a steady state. Dependent on the governing parameters, four steady-state flow regimes are possible, two of which are considered in this study. In one of these regimes, a flow is dominated by the drag while in the other one, the recently discovered regime of zonostrophic turbulence, a flow becomes strongly anisotropic and features slowly evolving systems of alternating zonal jets. Zonostrophic turbulence is distinguished by anisotropic inverse energy cascade and emergence of a new class of nonlinear waves known as zonons. In addition, meridional scalar diffusion is strongly modified in this regime. This paper provides an overview of various regimes of turbulence with a β-effect, elaborates main characteristics of frictiondominated and zonostrophic turbulence, elucidates the physical nature of the zonons, discusses the meridional diffusion processes in different regimes, and relates these results to oceanic observations.

Original languageEnglish
Pages (from-to)427-441
Number of pages15
JournalOcean Dynamics
Volume60
Issue number2
DOIs
StatePublished - 1 Apr 2010

Keywords

  • Geostrophic turbulence
  • Nonlinear waves
  • Turbulent diffusion

ASJC Scopus subject areas

  • Oceanography

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