The thermal structure of Jupiter II. Observations and analysis of 8–14 micron radiation

Abstract

Observations of Jovian limb structure at 8.11 and 8.45 microns are reported. These are used along with other limb structure and spectral data in the 8–14 micron region to derive a model of the thermal and cloud structure within the 1.0-0.01 bar pressure regime. The model is generally consistent with models derived from Pioneer 10 infrared radiometer data reported by Orton (1975b). The temperature is about 165K at 1.00 bar, 108K at 0.01 bar, and 143K at 0.03 bar. In zones, an optically opaque cloud of NH 3 exists near the 143K (0.60 bar) level. A partly transparent haze of solid NH 3 particles overlies the cloud. Belts are free of the cloud and have a much lower abundance of NH 3 haze than the zones. The data are consistent with an NH 3 gas abundance defined by saturation equilibrium, with a mixing ratio of 1.5 × 10 −4 deep in the atmosphere, and with a CH 4 mixing ratio of 2 × 10 −3, about three times the currently accepted value.