Quasi-geostrophic Rayleigh-Bénard convection on the tilted $f$-plane

Fuente: arXiv
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Main Authors: Miquel, Benjamin, Ellison, Abram, Calkins, Michael A., Julien, Keith, Knobloch, Edgar
Format: Preprint
Published: 2026
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author Miquel, Benjamin
Ellison, Abram
Calkins, Michael A.
Julien, Keith
Knobloch, Edgar
author_facet Miquel, Benjamin
Ellison, Abram
Calkins, Michael A.
Julien, Keith
Knobloch, Edgar
contents Rapidly rotating Rayleigh-Bénard convection on a $f$-plane at colatitude $\vartheta_f$ is investigated numerically using an asymptotically reduced equation set valid in the limit of very rapid rotation. The equations provide a non-hydrostatic but quasi-geostrophic description in a non-orthogonal coordinate system. The tilt changes the structure of the large-scale barotropic condensate from large-scale vortices to zonal flows as the colatitude of the $f$-plane increases, with bistable states present for certain parameter ranges, extending prior work to a geophysically significant parameter regime. This behaviour is understood through the impact of broken rotation symmetry on the barotropic source terms resulting from baroclinic vortical stresses and baroclinic torque. As the tilt angle $\vartheta_f$ increases, global heat and momentum transport is reduced relative to upright-polar convection, a result that is explained through linear theory and nonlinear power maps both of which demonstrate increased attenuation of the domain of dynamically active spatial scales as the convective modes depart from a North-South alignment in the horizontal plane. A key finding is that the predominance of lateral thermal mixing allows for the maintenance of a persistent unstable mean temperature gradient that saturates at increasing forcing levels and remains insensitive to the colatitude.
format Preprint
id arxiv_https___arxiv_org_abs_2602_20975
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Quasi-geostrophic Rayleigh-Bénard convection on the tilted $f$-plane
Miquel, Benjamin
Ellison, Abram
Calkins, Michael A.
Julien, Keith
Knobloch, Edgar
Fluid Dynamics
Rapidly rotating Rayleigh-Bénard convection on a $f$-plane at colatitude $\vartheta_f$ is investigated numerically using an asymptotically reduced equation set valid in the limit of very rapid rotation. The equations provide a non-hydrostatic but quasi-geostrophic description in a non-orthogonal coordinate system. The tilt changes the structure of the large-scale barotropic condensate from large-scale vortices to zonal flows as the colatitude of the $f$-plane increases, with bistable states present for certain parameter ranges, extending prior work to a geophysically significant parameter regime. This behaviour is understood through the impact of broken rotation symmetry on the barotropic source terms resulting from baroclinic vortical stresses and baroclinic torque. As the tilt angle $\vartheta_f$ increases, global heat and momentum transport is reduced relative to upright-polar convection, a result that is explained through linear theory and nonlinear power maps both of which demonstrate increased attenuation of the domain of dynamically active spatial scales as the convective modes depart from a North-South alignment in the horizontal plane. A key finding is that the predominance of lateral thermal mixing allows for the maintenance of a persistent unstable mean temperature gradient that saturates at increasing forcing levels and remains insensitive to the colatitude.
title Quasi-geostrophic Rayleigh-Bénard convection on the tilted $f$-plane
topic Fluid Dynamics
url https://arxiv.org/abs/2602.20975