Baroclinic toroidal quasi-geostrophic vortices
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We investigate the stability and nonlinear evolution of two tori of opposite-signed uniform potential vorticity, located one above the other, in a three-dimensional, continuously-stratified, quasi-geostrophic flow. We focus on the formation of het- ons as a result of the destabilisation of the tori of potential vorticity. Hetons are pairs of vortices of opposite-sign lying at different depths capable of transporting heat, momentum and mass over large distances. Particular attention is paid to the condition under which the hetons move away from their region of formation. We show that their formation and evolution depend on the aspect ratio of the tori, as well as the vertical gap separating them. The aspect ratio of a torus is the ratio of his major (centreline) radius to its minor (cross-sectional) radius. Pairs of thin opposite-signed potential vorticity tori self-organise into a large number of hetons. On the other hand, increasing the vertical gap between the tori decreases the cou- pling between the opposite-signed vortices forming the hetons. This results in a more convoluted dynamics where the vortices remain near the centre of the domain.
Reinaud , J N 2020 , ' Baroclinic toroidal quasi-geostrophic vortices ' , Physics of Fluids , vol. 32 , no. 5 , 056601 . https://doi.org/10.1063/5.0005942
Physics of Fluids
Copyright © 2020 the Author. Published under licence by AIP. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1063/5.0005942
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