Document Type

Article

Publication Date

2025

DOI

10.1029/2024JD042470

Publication Title

Journal of Geophysical Research: Atmospheres

Volume

130

Issue

21

Pages

e2024JD042470

Abstract

Carbon dioxide isotopologues have been studied thoroughly in the troposphere. In the stratosphere, the minor oxygen CO₂ isotopologues have anomalous abundances due to their exchange reactions with isotopically fractionated ozone, differentiating them from tropospheric CO₂. Previously a model predicted that this anomalous isotopic abundance continues into the mesosphere but lacked verification from experimental observations. Here we use the Atmospheric Chemistry Experiment Fourier Transform Spectrometer which records infrared transmittance spectra of the Earth's limb from low Earth orbit using solar occultation. These infrared spectra provide measurements of global CO₂ isotopologue volume mixing ratios (VMRs) from the upper troposphere to the lower thermosphere. Data for the O¹³CO, ¹⁷OCO and ¹⁸OCO isotopologues are presented, including seasonal altitude‐latitude VMR distributions. The role of photolysis in the upper atmosphere for ¹⁷OCO and ¹⁸OCO fractionation has been analyzed and found to be "mass independent."

Rights

© 2025. The Authors.

This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

Data Availability

Article states: "All ACE data is available after signup at https://databace.scisat.ca/level2/."

Original Publication Citation

English, D., Bernath, P., & Boone, C. (2025). CO₂ isotopologues from the ACE satellite. Journal of Geophysical Research: Atmospheres, 130(21), Article e2024JD042470. https://doi.org/10.1029/2024JD042470

ORCID

0000-0002-1255-396X (Bernath)

2024jd042470-sup-0001-supporting information si-s01.pdf (532 kB)
Supporting Information S1

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