Jupiter's Atmospheric Composition and Cloud Structure Deduced from Absorption Bands in Reflected Sunlight

Abstract

Abstract The spectrum of sunlight reflected by Jupiter is analyzed by comparing observations of Woodman et al. (1979) with multiple-scattering computations. The analysis yields information on the vertical cloud structure at several latitudes and on the abundance of CH4 and NH3 in the atmosphere of Jupiter. The abundance of CH4, is (1.8±0.4) × 10−3 for [CH4]/[H2], which corresponds to a carbon abundance 2±0.4 times that in the atmosphere of the sun for currently accepted values of the solar composition. The quoted limits for the abundance include the effects of uncertainties in the cloud and haze structure. The abundance of NH3 is (2.8±1.0) × 10−4 for [NH3]/[H2] in the region between 1 bar and 3–5 bars, corresponding to a nitrogen abundance 1.5±0.5 times that in the atmosphere of the sun. Thus nitrogen is at least as abundant on Jupiter as on the sun, and it may exceed the abundance in the solar atmosphere by a factor as great as that for carbon. These abundances suggest that all ices (and rocks) are overa...