New Non-LTE Model of the IR emissions of Hydroxyl, Ozone and Carbon Dioxide in the nighttime MLT
Abstract
We present a new non-LTE model which couples IR emissions of OH, O_3 and CO_2 bands in the nighttime MLT. The model treats a large number of vibrational levels and ro-vibrational bands of these three optically active molecules as well of N_2(v) and O_2(v), which all are coupled by a variety of inter- and intra-molecular collisionally induced exchanges of vibrational energy. We compare model calculations of limb emissions in the 1.6 and 2.0 μm OH Meinel bands, 9.6 μm O_3 band and 4.3 μm CO_2 band with nighttime limb radiances measured by SABER/TIMED. Particular attention is given to the effect of the recently discovered mechanism of OH(v) quenching by collisions with O(^3P), subsequently producing O(^1D), which further transfers its energy to the N_2, CO_2 and O_3 vibrations, and therefore influencing OH, O_3, and CO_2 emissions.We also present a novel retrieval algorithm and show the application of the new model/algorithm to retrieving O(^3P) and OH densities in MLT from the OH 1.6 and 2.0 μm Meinel band emissions measured by SABER. We compare retrieved densities with observations of other airglow emissions (WINDII, OSIRIS, SCIAMACHY), as well as model results of WACCM. Implications for the aeronomy and energy budget of the MLT are discussed.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E2571P