Deep model simulation of polar vortices in gas giant atmospheres

TL;DR

This paper presents advanced 3D convective models that successfully simulate long-lived polar vortices in gas giants, matching observed features like Saturn's hexagon and Jupiter's polar cyclones, suggesting deep interior origins.

Contribution

The study introduces new deep convection simulations that reproduce realistic polar vortices and analyze their force balances, extending understanding beyond shallow atmospheric models.

Findings

Simulations produce polar vortices similar to those observed by Juno and Cassini.

Identifies a transition between different polar flow regimes based on force balances.

Confirms scaling laws for heat transport in giant planet 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.