Deep model simulation of polar vortices in gas giant atmospheres

Abstract

The Cassini and Juno probes have revealed large coherent cyclonic vortices in the polar regions of Saturn and Jupiter, a dramatic contrast from the east-west banded jet structure seen at lower latitudes. Debate has centered on whether the jets are shallow, or extend to greater depths in the planetary envelope. Recent experiments and observations have demonstrated the relevance of deep convection models to a successful explanation of jet structure and cyclonic coherent vortices away from the polar regions have been simulated recently including an additional stratified shallow layer. Here we present new convective models able to produce long-lived polar vortices. Using simulation parameters relevant for giant planet atmospheres we find flow regimes that are in agreement with geostrophic turbulence (GT) theory in rotating convection for the formation of large scale coherent structures via an upscale energy transfer fully three-dimensional. Our simulations generate polar characteristics qualitatively similar to those seen by Juno and Cassini: they match the structure of cyclonic vortices seen on Jupiter; or can account for the existence of a strong polar vortex extending downwards to lower latitudes with a marked spiral morphology and the hexagonal pattern seen on Saturn. Our findings indicate that these vortices can be generated deep in the planetary interior. A transition differentiating these two polar flows regimes is described, interpreted in terms of different force balances and compared with previous shallow atmospheric models which characterised polar vortex dynamics in giant planets. In addition, the heat transport properties are investigated confirming recent scaling laws obtained in the context of reduced models of GT.

18 pages, 13 figures and 3 tables

References in corpus (6)

• Constraints on Deep-seated Zonal Winds Inside Jupiter and Saturn
• Scaling regimes in spherical shell rotating convection
• Patterns of convection in rotating spherical shells
• Transition between viscous dipolar and inertial multipolar dynamos
• Seasonal Evolution of Saturn's Polar Temperatures and Composition
• Power Spectral Analysis of Jupiter's Clouds and Kinetic Energy from Cassini

Cited by in corpus (5)

• Deep convection-driven vortex formation on Jupiter and Saturn
• The number and location of Jupiter's circumpolar cyclones explained by vorticity dynamics
• The Oscillatory Motion of Jupiter's Polar Cyclones Results From Vorticity Dynamics
• Weak branch and multimodal convection in rapidly rotating spheres at low Prandtl number
• Real Schur flow computations, helicity fastening effects and Bagua-pattern cyclones