STRUCTURE OF THE ATMOSPHERE OF JUPITER - GALILEO PROBE MEASUREMENTS

Temperatures and pressures measured by the Galileo probe during parach ute descent into Jupiter's atmosphere essentially followed the dry adi abat between 0.41 and 24 bars, consistent with the absence of a deep w ater cloud and with the low water content found by the mass spectromet er. From 5 to 15 bars, lapse rates were slightly stable relative to th e adiabat calculated for the observed H-2/He ratio, which suggests tha t upward heat transport in that range is not attributable to simple ra dial convection, In the upper atmosphere, temperatures of >1000 kelvin at the 0.01-microbar level confirmed the hot exosphere that had been inferred from Voyager occultations. The thermal gradient increased sha rply to 5 kelvin per kilometer at a reconstructed altitude of 350 kilo meters, as was recently predicted, Densities at 1000 kilometers were 1 00 times those in the preencounter engineering model.