Anisotropic Turbulence and Rossby Waves in an Easterly Jet: An Experimental Study

Boris Galperin, Jesse Hoemann, Stefania Espa, Gabriella Di Nitto

Research output: Contribution to journalArticlepeer-review

Abstract

A westward propagating jet is investigated experimentally. The focus is on complex interaction between anisotropic turbulence with inverse energy cascade and Rossby waves. The energy spectrum is highly anisotropic. To diagnose turbulence characteristics, we explore the analogy between turbulent overturns in stably stratified and quasi-geostrophic flows and develop a novel method based upon the monotonizing of potential vorticity (PV). The RMS displacement from the monotonic PV profile yields a length scale, L M , analogous to the Thorpe's scale used in flows with stable stratification. As the Thorpe scale is proportional to the Ozmidov scale, the scale L M is proportional to the scale L β at which the time scales of turbulent overturns and Rossby waves are approximately equal. The relationship between L M and L β is established here for the first time. The method of PV monotonizing offers a simple and powerful tool for diagnosing geophysical and planetary macroturbulence.

Original languageAmerican English
JournalGeophysical Research Letters
Volume41
DOIs
StatePublished - Jan 1 2014

Keywords

  • zonal jets
  • planetary macroturbulence
  • Thorpe scale

Disciplines

  • Life Sciences

Cite this