Shallow Water Modeling of Jovian Polar Cyclone and Vortices

Jupiter’s polar atmosphere was observed for the first time by the Juno visible spectrum camera (JunoCAM) and Juno Infrared Auroral Mapper (JIRAM). Both the visible and infrared images show active vortices and weather systems that unlike any polar regions previously seen or modeled on any of the planets in our solar system. We developed an ultra-high resolution global shallow water model on a sphere with poles rotated to the equator to investigate the formation, maintenance and dynamic regimes controlling the morphology of polar cyclone and vortices. We verified that a westward barotropically unstable jet can spontaneously break the axial symmetry into a polygon-shaped figure rotating rigidly around the rotation axis as reported by previous laboratory experiments. The number of sides of the polygon depends on the deformation radius and is insensitive to the initial condition. In contrast, an unstable eastward jet will break into small vortices that mimics the polar image of Jupiter.