P3.17
Equatorial superrotation on giant planets driven by internal convection
Yohai Kaspi, MIT, Cambridge, MA; and G. R. Flierl
Jupiter and Saturn's atmospheres are dominated by multiple zonal jets with strong superrotation around the equator. We have modified the MIT general circulation model to be suitable for giant planets. The model's geometry is a full 3D sphere down to an inner core (unlike the traditional spherical shell). It is non-hydrostatic, anelastic, uses an equation of state suitable for hydrogen-helium mixtures (SCVH), and is driven by internal heat. In the parameter regime suitable for giant planets the convective plumes tend to align with the direction of the rotation axis. We find that the baroclinic density gradients caused by the convection drive the system away from the Taylor-Proudman constraint, to a state closer to having the total zonal momentum rather than the velocity itself constant along the rotation axis. The convection drives large positive vorticity columnar eddies supporting superrotating flows around the equator.
Poster Session 3, General Circulation and Low-Frequency Variability
Wednesday, 27 June 2007, 10:30 AM-12:00 PM, Ballroom North
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