Banded convection in rotating fluid spheres and the circulation of the Jovian atmosphere

Laboratory experiments of thermal convection in rotating spherical shells exhibit symmetric bands and alternating zonal jets in a thin layer near the outer boundary at high rotation rates and at Rayleigh numbers far in excess of the critical value. The bands result from large-scale ordering of small-scale columnar convection deeper in the shell and the zonal jets are secondary flows derived from the columnar convection. The number of bands and the strength of the zonal jets increase with increasing rotation rate and with increasing Rayleigh number of the convection. The bands are best defined in the fluid outside of the cylinder tangent to the inner spherical boundary. In a spherical shell with an inner/outer radius ratio r = 0.76, the expected geometry of the molecular hydrogen layer in Jupiter, the bands occupy the region within +/-45 degrees of the equator. The presence of jets and bands in these experiments support the conjecture that the zonal winds on Jupiter are maintained by deep convection. (C) 1996 Academic Press, Inc.