Numerical study of the McIntyre instability around Gaussian floating vortices in thermal wind balance

TL;DR

This study uses numerical simulations and stability analysis to investigate the McIntyre instability's role in density layering around vortices, confirming its significance in laboratory settings but questioning its applicability to oceanic meddies.

Contribution

It provides a quantitative assessment of the McIntyre instability's effects on vortex-induced layering using idealised models and stability analysis.

Findings

McIntyre instability causes layering around laboratory vortices.

Its relevance to meddy layering is doubtful.

Numerical simulations support the instability's role in laboratory conditions.

Abstract

The visco-diffusive McIntyre instability (McIntyre 1970) has been suggested as a possible source for density layer formation around laboratory and oceanic vortices. This suggestion is here quantitatively addressed using idealised, axisymmetric, numerical simulations of a simple Gaussian-like vortex in thermal wind balance, floating in a rotating, stratified flow. Numerical simulations are complemented by a local stability analysis derived from the seminal study (McIntyre 1970). It is confirmed that the McIntyre instability is responsible for the layering observed around laboratory vortices, but its relevance for explaining layering around meddies remains doubtful.