Williams, G. P., 1978: Planetary Circulations: 1. Barotropic representation of Jovian and terrestrial
turbulence. Journal of the Atmospheric Sciences, 35, 1399-1426.
Abstract: We seek the formative processes of the planetary circulations of Jupiter
and Saturn. the study concentrates on examining whether processes known
to control the terrestrial circulation, namely, two-dimensional turbulence
and baroclinic instability, can produce Jovian circulations under Jovian
conditions. The first numerical model involves a spherical barotropical
vorticity equation subjected to a stochastic representation of baroclinic
processes. The resulting solutions suggest that a strong affinity exists
between the Jovian and terrestrial circulations. This leads to a reevaluation
of terrestrial circulation theory from the broader perspective of parameter
space.
The solutions in the Jovian regime support the hypothesis that a variation
of the Rhines effect-an interaction of the two-dimensional turbulence cascade
and Rossby wave propagation-creates the pseudo-axisymmetry and scale of
the bands. The anisotropy of the interaction produces zonally oriented flows,
composed of a series of alternating easterly and westerly jets, between
which lie characteristic ovals. Equatorial jets occur readily when vorticity
sources that lie symmetrically about the equator act on the atmosphere.
Frictionally induced Ekman circulations provide a possible mechanism for
cloud formation.
Integrations with terrestrial parameters support Kuo's (1951) forced vorticity-transfer
theory for the Earth's circulation: westerly jets form in the forces midlatitude
zones, and Rossby-wave propagation from those zones causes the broad easterly
trade winds. Enstrophy cascade and B effects control the formation of momentum converging eddy patterns. LB also provides a measure of the width of the terrestrial jet. Cascade blocking
by a stronger surface drag prevents terrestrial flows from approaching the
same degree of zonality as Jovian ones.
Jupiter also appears to be dynamically equivalent to a hypothetical (or
primeval) global ocean that has neither continental boundaries nor surface
winds.