Banded surface flow maintained by convection in a model of the rapidly rotating giant planets.

In three-dimensional numerical simulations of a rapidly rotating Boussinesq fluid shell, thermally driven convection in the form of columns parallel to the rotation axis generates an alternately directed mean zonal flow with a cylindrical structure. The mean structure at the outer spherical surface consists of a broad eastward flow at the equator and alternating bands of westward and eastward flows at higher latitudes in both hemispheres. The banded structure persists even though the underlying convective motions are time-dependent. These results, although still far from the actual motions seen on Jupiter and Saturn, provide support for theoretical suggestions that thermal convection can account for the remarkable banded flow structures on these planets.