Fig. 1.

A shows the azimuthally averaged zonal flow on the outer boundary of the simulation (left axis) and for Saturn (right axis). B shows the azimuthally averaged zonal flow on a meridional plane. The simulation data are time averaged over a few rotations of the shell. The zonal velocity magnitude is given in terms of the Rossby number defined here as $u/\left(\mathrm{\Omega }{r}_o\right)$, where $u$ is velocity, $\mathrm{\Omega }$ is shell rotation rate, and $r_o$ is outer radius of the shell. The Rossby number for Saturn is calculated using the observed cloud-level zonal flow velocities, Saturn’s mean radius $5.8232\times 10^7$ m, and the rotation period $1.64\times 10^{-4}$ rad/s in System IIIw (6).