Saturn's South Polar Vortex: Idealized 2-layer Experiments of Vorticity Mixing

The Cassini mission has provided unprecedented high-resolution observations of Saturn's atmosphere. Among many recent discoveries, a massive warm-core cyclonic vortex has been observed on the south pole: Saturn's South Polar Vortex (SPV). The SPV has the highest measured temperatures on Saturn and in many ways resembles the gross features of a terrestrial tropical cyclone, with a double eyewall, deep eye and a rapid cyclonic jet with the second highest windspeeds observed on the planet. However, in part because Saturn lacks the thermal disequilibrium mechanism understood to be the energy source for tropical cyclones, scientists have yet to explain its dynamics and energy source. Interestingly, numerous small, vortical and potentially convective systems are embedded within the large-scale flow of the SPV. We explore one potential mechanism of vortex maintenance: up-scale vorticity flux due to vortical hot towers (VHTs). Using a two-layer shallow water model on a polar β-plane, we represent deep convection with mass flux-induced hetons and allow them to move freely. Results are presented for experiments with and without a cyclonic, large-scale background flow.