Statistical equilibrium predictions of jets and spots on Jupiter

An equilibrium statistical theory of coherent structures is applied to midl atitude bands in the northern and southern hemispheres of Jupiter. The theo ry imposes energy and circulation constraints on the large-scale motion and uses a prior distribution on potential vorticity fluctuations to parameter ize the small-scale turbulent eddies. Nonlinearly stable coherent structure s are computed by solving the constrained maximum entropy principle governi ng the equilibrium states of the statistical theory. The theoretical predic tions are consistent with the observed large-scale features of the weather layer if and only if the prior distribution has anticyclonic skewness, mean ing that intense anticyclones predominate at small scales. Then the computa tions show that anticyclonic vortices emerge at the latitudes of the Great Red Spot and the White Ovals in the southern band, whereas in the northern band no vortices form within the zonal jets. Recent observational data from the Galileo mission support the occurrence of intense small-scale anticycl onic forcing. The results suggest the possibility of using equilibrium stat istical theory for inverse modeling of the small-scale characteristics of t he Jovian atmosphere from observed features.