Radiative transfer processes in outer planetary atmospheres

Abstract

With the exception of Jupiter, none of the atmospheres of the giant planets has been directly sampled. Even with Jupiter the only in situ measurements that are available were made from the Galileo entry probe, which sampled a single, probably not very representative, region of the planet, namely a 5 µm hotspot. Hence, the bulk of our knowledge of the composition, cloud structure, and dynamics of these planets has not come from direct measurements, but instead has come indirectly from analyzing features in their electromagnetic spectrum, measured by ground-based telescopes, Earth-orbiting telescopes, and from specific flyby and orbiting spacecraft missions. There are two main components of the observed spectra that provide atmospheric information: reflected sunlight from the cloud and haze layers, and thermal emission from the atmosphere itself.