Apparaît dans la collection : 2026 - T2 - WS3 - Idealised mathematical models for geophysical flows

Planetary cores and the subsurface oceans of icy moons are stirred by quasi-geostrophic turbulent convection. The transport (of heat, momentum, etc.) by the flow vary regionally with the colatitude, which coincides with the tilt angle between gravity and rotation. Here, we analyse rapidly rotating Rayleigh-Benard convection in a local model: the tilted f-plane. Employing non-orthogonal coordinates, we obtain a natural formulation for geostrophy and a set of governing equations for the non-hydrostatic quasi-geostrophic dynamics on the tilted f-plane (fNHQGE), valid in the asymptotic limit of rapid rotation.

We conduct a systematic parametric study by varying the Rayleigh number and the tilt angle. As the tilt increases, the barotropic condensate transitions from large scale vortices (near the pole) to East-West jets (near the equator), with bistability at intermediate latitudes. Concomitantly, both heat transport and the vertical kinetic energy decrease monotonically with colatitude.

Co-authors: A. Ellison, M. Calkins, K. Julien, E. Knobloch