zonal jets, planetary macroturbulence, Thorpe scale
Digital Object Identifier (DOI)
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, LM, analogous to the Thorpe's scale used in flows with stable stratification. As the Thorpe scale is proportional to the Ozmidov scale, the scale LM is proportional to the scale Lβ at which the time scales of turbulent overturns and Rossby waves are approximately equal. The relationship between LM and Lβ is established here for the first time. The method of PV monotonizing offers a simple and powerful tool for diagnosing geophysical and planetary macroturbulence.
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Citation / Publisher Attribution
Geophysical Research Letters, v. 41, issue 17, p. 6237-6243
©2014. American Geophysical Union. All Rights Reserved.
Scholar Commons Citation
Galperin, Boris; Hoemann, Jesse; Espa, Stefania; and Nitto, Gabriella Di, "Anisotropic Turbulence and Rossby Waves in an Easterly Jet: An Experimental Study" (2014). Marine Science Faculty Publications. 1496.