Exploring Jupiter's Polar Deformation Lengths with High Resolution Shallow Water Modeling

TL;DR

This study uses a high-resolution shallow water model to explore how polar moist convective events influence Jupiter's high-latitude dynamics, revealing the role of deformation length and turbulent forcing in FFR formation and vortex stability.

Contribution

Introduces a novel high-resolution shallow water model to analyze polar Jovian phenomena, linking deformation length and turbulence to FFR and vortex formation.

Findings

Models with larger deformation length tend to form stable polar cyclones.

High turbulent forcing scales lead to the formation of FFRs.

Moist convection at high latitudes can produce observed Jovian polar dynamics.

Abstract

The polar regions of Jupiter host a myriad of dynamically interesting phenomena including vortex configurations, folded-filamentary regions (FFRs), and chaotic flows. Juno observations have provided unprecedented views of the high latitudes, allowing for more constraints to be placed upon the troposphere and the overall atmospheric energy cycle. Moist convective events are believed to be the primary drivers of energetic storm behavior as observed on the planet. Here, we introduce a novel single layer shallow water model to investigate the effects of polar moist convective events at high resolution, the presence of dynamical instabilities over long timescales, and the emergence of FFRs at high latitudes. We use a flexible, highly parallelizable, finite-difference hydrodynamic code to explore the parameter space set up by previous models. We study the long term effects of deformation length (Ld), injected pulse size, and injected geopotential. We find that models with Ld beyond 1500 km (planetary Burger number, Bu$=4.4\times10^{-4}$) tend to homogenize their potential vorticity (PV) in the form of dominant stable polar cyclones, while lower Ld cases tend to show less stability with regards to Arnol'd-type flows. We also find that large turbulent forcing scales consistently lead to the formation of high latitude FFRs. Our findings support the idea that moist convection, occurring at high latitudes, may be sufficient to produce the dynamical variety seen at the Jovian poles. Additionally, derived values of localized horizontal shear and Ld may constrain FFR formation and evolution.