A Topographic Perspective on Jupiter’s Great Red Spot: Insights from Ocean Circulation Models

Abstract

In a recent study using an Ocean General Circulation Model (OGCM) it was shown that the forcing by the surface vertical velocity generated a significant vorticity to that generated by the curl of the wind stress forcing.  On Jupiter the surface vertical velocity is the only source of vorticity, and the Coriolis force is very similar to that in the sub-tropics on Earth. This leads to a plausible mechanism for the existence of the Great Red Spot (GRS) which is investigated in this paper. The properties which are modelled include the topography of the GRS, which is predicted to be a tabletop mountain of probable height about 1 km, situated on a surrounding gently sloping plain extending outwards over approximately 2000 km.  On this plain, the upward vertical velocity brings fluid to the surface, where we propose it is trapped in a fluidic mixed layer probably of a few meters thickness beneath the intensely cold icy cap.  This is analogous to the formation of a mixed layer in the oceans on Earth   The time scale for heat exchange with the atmosphere is probably about 10 hrs, similar to the rotation period of Jupiter.