THE SOUTH EQUATORIAL BELT OF JUPITER .2. THE ONSET AND DEVELOPMENT OFTHE 1993 DISTURBANCE

On April 6, 1993 an SEB disturbance commenced with a bright white spot at 15.5 degrees S latitude, The spot was followed by a dark column ly ing only 24 degrees from the eastern edge of the Great Red Spot. A con tinuous CCD and photographic survey at visual wavelengths of the el ml during the four months following the eruption has allowed us to obtai n the best imaging records of the evolution of an SEB disturbance, wit h a spatial resolution and temporal coverage of unprecedent quality, A high resolution zonal wind velocity profile in the 8 degrees S to 25 degrees S latitude range has been obtained tracking the cloud elements pertaining to the SEBD and nearby features, The SEBD central and nort hern branches developed according to the classical morphology patterns and values of the zonal winds as described in paper I, However, this SEBD event was marked by the unusual proximity of the onset site to th e GRS and by the interaction of the SEBD spots with preexisting featur es in the STrZ, The new phenomena observed included: (i) A temporal de lay in the development of the SEBD southern branch spots, that moved w ith lower velocities (at about 30 m sec(-1)) than those observed on th e average in other events; (ii) The interaction of a preexisting STrZ disturbance with the GRS and the SEBD southern branch features; (iii) The interaction of the features of the central branch with a long-live d anticyclonic vortex in the STrZ, The revival of the SEB was complete in November 1993, entering the belt during 1993 in an SEBD1 phase (as described in paper I) which was characterized at continuum wavelength s by the formation of a STrZ belt at similar to 23.5 degrees S and by the presence of synoptic and rapidly changing white spots at 11.5 degr ees S, This activity formed tilted cloud patterns of turbulence in the northern half of the belt in a region that corresponds to the cycloni c southern half of the strong eastward jetstream at similar to 7 degre es S. (C) 1996 Academic Press, Inc.