Abstract

Atomic oxygen and translational temperature play vital roles in the chemistry and heat balance of the earth's atmosphere above 80 km. However, existing techniques, both in situ and remote, for measuring vertical profiles of the temperature and O-atom density at these altitudes have severe limitations; see, eg., Zachor and Sharma (1989). Described in the present paper is a new remote sensing technique in which the data is a pair of limb radiance profiles corresponding to the spectrally unresolved 147 μm and 63 μm lines of atomic oxygen (the inter-multiplet transitions ³P₀ → ³P₁ and ³P₁ → ³P₂ of the ground electronic state). We outline a retrieval procedure that uses both the onion peeling and global-fit methods to recover temperature and O-atom density between 90 km and 300 km altitude. The global-fit technique (Carlotti, 1988), which provides solution values simultaneously for several altitudes, is used only near 200 km altitude, where a singular Jacobian causes the onion peeling method to diverge. The retrieval procedure was applied to noise-contaminated synthetic data in order to establish basic system requirements for a spaceborne sensor. It is concluded that the proposed remote sensing technique can be implemented with a small cryogenic sensor system based on (non-scanning) Fabry-Perot etalons and detectors having current state-of-the-art performance.

© 1990 Optical Society of America