- 1The Catholic University of America, Institute for Astrophysics and Computational Sciences, Physics Department, Washington, United States of America (kutepov@cua.edu)
- 2LMD/IPSL, Sorbonne Université, UPMC Univ Paris 06, CNRS, École polytechnique, Palaiseau, France
- 4Center for Geospace Studies, SRI International, Menlo Park, CA, USA
The year 2025 marks the 55th anniversary of Paul Crutzen’s brilliant hypothesis that collisions of the carbon dioxide molecules with oxygen atoms is the dominant process responsible for excitation of the bending vibrational mode of carbon dioxide and, thus, the resulting 15-µm infrared (IR) emission from vibrationally excited CO2 provides a remote sensing window into the temperature profiles, energy budget, and thermal balance of the upper atmosphere. The O + CO2 problem has remained open for the past five decades due to unacceptably large discrepancies between the laboratory measurements of the rate constant for this process, its values retrieved from space-based observations, and the rate constant values used in general circulation models (GCMs) for estimating CO2 cooling of the mesosphere and lower thermosphere (MLT).
We have been actively engaged in research efforts to address this problem by revisiting its different aspects, including theoretical analysis, atmospheric modeling, and laboratory experiments investigating the processes leading to the generation of the 15-µm emission in the Earth’s MLT region. This report discusses our recent progress on this topic. We will present non-local thermodynamic equilibrium (non-LTE) modeling calculations on the MLT 15-µm cooling using our recently published, optimized version of the Accelerated Lambda Iteration for Atmospheric Radiation and Molecular Spectra (ALI-ARMS) research code [Kutepov and Feofilov, 2024]. Detailed comparisons of these results with the parameterizations of this cooling used in GCMs and remote sensing by space-based observations will be discussed.
This research is supported by grants from the US National Science Foundation (AGS-2312191/92, AGS-2125760) and NASA (80NSSC21K0664).
References
Kutepov, A. and Feofilov, A., 2024. New routine NLTE15µmCool-E v1. 0 for calculating the non-local thermodynamic equilibrium (non-LTE) CO2 15 µm cooling in general circulation models (GCMs) of Earth’s atmosphere. Geoscientific Model Development, 17(13), 5331-5347.
How to cite: Kutepov, A., Feofilov, A., Rezac, L., and Kalogerakis, K.: Studies to Resolve a Persistent Upper Atmospheric Mystery, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7102, https://doi.org/10.5194/egusphere-egu25-7102, 2025.
