High-Resolution Observations of Jupiter's 300-mbar Temperature Field by the PPR Experiment from Galileo's Europa-16 Orbit

From the ashes of Galileo's Europa-16 orbit, in which a spacecraft safing event deleted almost all atmospheric observations, come two sets of high-spatial resolution maps of Jupiter's 300-mbar temperature field using the 27-mu m radiometric channel of the Photopolarimeter-Radiometer (PPR) experiment. The first of these is an observation of a new white oval (see Fisher et al. this meeting), observed at ~ 1800-km resolution. The oval is unmistakenly defined as a distinct cold feature, ~ 10,000 - 18,000 km, roughly commensurate with the same feature as defined by high-altitude particulates observable in the near infrared (again,see Fisher et al.). The 300-mbar temperature of the interior of the spot, ~ 115.8 K, is uniform to the extent of our spatial resolution and ~ 1.2 K colder than the general surroundings. The oval appears to be surrounded by a narrow ring at the limit of our spatial resolution that is ~ 0.5 K warmer than the surrounding material. The spot lies to the immediate north of a region that is uniformly about 1 K warmer than the general area at the latitude of of the white oval. The second region mapped is a broad area in the northern hemisphere from 3(deg) to 27(deg) N planetocentric latitude and 35(deg) to 100(deg) System-III longitude, observed at ~ 1600-km resolution. The latitude range includes portions of the axisymmetric features known as the Equatorial Zone (EZ), North Equatorial Belt (NEB), North Tropical Zone (NTrZ) and the North Temperate Belt (NTB). There is much detail in the temperature structure, with a temperature range from 124.8 K in the peak of a NEB wave to 117.0 K in the coldest part of a NTrZ zonal wave. The warm NTB extends further south than its boundary in the visible or 5-mu m cloud field. There is striking zonal wave structure in the NEB, and considerable detail is apparent at the smallest spatial scales. High temperatures are correlated with the width of the NEB in the thermal field. These, in turn appear to be correlated with the width of the NEB in the cloud field and the longitudes of 5-mu m hot spots, perhaps coincidentally. There is a clear mixture of large- and small-scale structure correlations and non-correlations between the temperature and cloud fields that must be sorted out.