HR: 17:45h
AN: P44A-08    [Abstracts]
TI: Modeling Zonal Flows on the Giant Planets
AU: * Heimpel, M H
EM: mheimpel@phys.ualberta.ca
AF: University of Alberta, Department of Physics, Edmonton, AB T6G 2J1 Canada
AU: Aurnou, J M
EM: aurnou@ucla.edu
AF: UCLA, Department of Earth and Space Sciences, Los Angeles, CA 90095-1567 United States
AB: Large-scale zonal flows, as observed on the giant planets, can result from deeply driven thermal convection in a rapidly rotating spherical shell. Using 3D numerical models, we study the affects of velocity boundary conditions and spherical shell geometry on zonal flow generation. The radius ratio, $\chi = r_i/r_o$, where $r_i$ is the inner shell boundary and $r_o$ is the outer shell boundary, is varied over the range $0.60 \le \chi \le 0.923$. The resulting surface zonal flow Rossby numbers for the models are comparable to those measured on the giant planets. In all our calculations a prograde barotropic jet forms in the equatorial region. This jet is flanked by large-scale alternating baroclinic jets at higher latitudes. Near the poles, an upwelling along the rotation axis is associated with a strong vortex structure. Superimposed on this are small-scale zonal flows driven by local 3D vortical convection that occurs only in this polar region. Scaling behavior for the number of alternating jets and their strength will be presented. The relevance of our numerical models to the characteristics and differences between zonal flows on Jupiter and Saturn will be discussed.
DE: 5707 Atmospheres--structure and dynamics
DE: 3230 Numerical solutions
DE: 3314 Convective processes
DE: 3319 General circulation
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting