Abstract

The main features of limb scanning derive directly from the view geometry. The thermal radiation emitted by a gas along the tangential path through the atmosphere is seen against the cold background of space. These factors enhance the sensitivity to the emission of trace gases, and allow weak features to be seen up to altitudes limited only by the noise level of the instrument and the uncertainty of the background determination. Emission spectra of the atmosphere show features of the "major" (ppmv) trace species--CO₂, O₃, H₂O, CH₄ and N₂O as well as species present only in ppbv amounts--HNOg and NOg, with interference from gases present in even smaller concentrations.

© 1985 Optical Society of America