BELT-ZONE VARIATIONS IN THE JOVIAN CLOUD STRUCTURE

Voyager IRIS observations of Jupiter in the far infrared (180-1200 cm- 1) are sensitive to emission originating from pressures less than 2 ba rs, while the 5-mum (1800-2300 cm-1) observations are primarily sensit ive to emission, originating from pressures greater than 2 bars. We us e these differences in the location of the peak emission level to cons train the properties of the upper tropospheric cloud structure from th e far-infrared observations and then use the 5-mum observations, with the upper tropospheric cloud structure fixed, to constrain the deep cl oud structure. The relationship between observed 45- and 5-mum brightn ess temperatures reveals three distinct regions between +/-25-degrees latitude: North Equatorial Belt hot spots, which are ''hot'' at both 4 5 and 5 mum; Equatorial Zone spectra, which are ''warm'' at 45 mum and ''cold'' at 5 mum; and North Tropical Zone spectra, which are ''cold' ' at both 45 and 5 mum. We find that the hot extreme spectral ensemble is unique to belts, and the cold extreme spectral ensembles are uniqu e to zones, but that all other intermediate spectral ensembles are com mon to both regions. Analyses of these spectra using an anisotropic mu ltiple scattering radiative transfer model reveal that the primary dif ference between belts and zones is the increased opacity and vertical extent of clouds in zones relative to their belt counterparts. In addi tion, we find a shift in the location of the para hydrogen gradient to ward lower pressures in zones, with an increase in the ''equilibrated' ' cloud-top para fraction. We suggest that all of the variations in ga s abundance profiles, temperature, and cloud structure are consistent with the effects of a simple mean circulation and large-scale wave mot ions.