8.4
Generation of multiple jets and equatorial superrotation on Jupiter
Junjun Liu, Environmental Science and Engineering, Pasadena, CA; and T. Schneider
In Jupiter's upper atmosphere, the heat flux emanating from the interior is of the same order of magnitude as the solar radiative flux. Here we show by means of simulations with a general circulation model that coupling of the convective flux to large-scale waves in an upper-atmospheric weather layer can account for the observed structure of winds in Jupiter's upper atmosphere, with strong equatorial superrotation and multiple jets in the extratropics.
In the model, solar radiative fluxes are deposited in the upper atmosphere by absorption and scattering, and a temporally constant and spatially homogeneous heat flux is imposed at the bottom boundary. Convection transports heat from the bottom boundary to the upper atmosphere. When the imposed heat flux at the bottom boundary is of the same order as Jupiter's interior heat flux (O(10 W/m2)), both multiple jets and strong equatorial superrotation are generated in the upper atmosphere. The extratropical jets are generated and organized by large-scale eddies, which receive their kinetic energy at convective scales, from where it cascades to large scales in an inverse energy cascade. For sufficiently strong imposed heat fluxes at the bottom boundary, convectively coupled waves generated in the equatorial region propagate out from the equatorial region into higher latitudes, leading to eddy momentum transport into the equatorial region and thus to equatorial superrotation.
.Session 8, Jets and Wave-Mean Flow Interactions
Tuesday, 26 June 2007, 3:15 PM-5:00 PM, Ballroom South
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