Retrieval of mesospheric and lower thermospheric kinetic temperature from measurements of CO₂ 15 µm Earth Limb Emission under non‐LTE conditions

Abstract

We present a new algorithm for the retrieval of kinetic temperature in the terrestrial mesosphere and lower thermosphere from measurements of CO 2 15 µm earth limb emission. Non‐local‐thermodynamic‐equilibrium (non‐LTE) processes are rigorously included in the new algorithm, necessitated by the prospect of satellite‐based limb radiance measurements to be made from the TIMED/SABER platform in the near future between 15 km and 120 km tangent altitude. The algorithm requires 20 seconds to retrieve temperature to better than 3 K accuracy on a desktop computer, easily enabling its use in operational processing of satellite data. We conclude this letter with a study of the sensitivity of the retrieved temperatures to parameters used in the non‐LTE models, including sensitivity to the rate constant for physical quenching of CO 2 bending mode vibrations by atomic oxygen.