Absorption coefficient (ABSCO) tables for the Orbiting Carbon Observatories: Version 5.1

Journal Article · Sun Nov 01 00:00:00 EDT 2020 · Journal of Quantitative Spectroscopy and Radiative Transfer

DOI:https://doi.org/10.1016/j.jqsrt.2020.107217· OSTI ID:1646512

Payne, Vivienne H.; Drouin, Brian J.; Oyafuso, Fabiano; Kuai, Le; Fisher, Brendan M.; Sung, Keeyoon; Nemchick, Deacon; Crawford, Timothy J.; Smyth, Mike; Crisp, David; Adkins, Erin; Hodges, Joseph T.; Long, David A.; Mlawer, Eli J.; Merrelli, Aronne; Lunny, Elizabeth; O’Dell, Christopher W.

The accuracy of atmospheric trace gas retrievals depends directly on the accuracy of the molecular absorption model used within the retrieval algorithm. For remote sensing of well-mixed gases, such as carbon dioxide (CO₂), where the atmospheric variability is small compared to the background, the quality of the molecular absorption model is key. Recent updates to oxygen (O₂) absorption coefficients (ABSCO) for the 0.76 μm A-band and the water vapor (H₂O) continuum model within the 1.6 μm and 2.06 μm CO₂ bands used within the Orbiting Carbon Observatory (OCO-2 and OCO-3) algorithm are described here. Updates in the O₂ A-band involve the inclusion of new laboratory measurements within multispectrum fits to improve relative consistency between O₂ line shapes and collision-induced absorption (CIA). The H₂O continuum model has been updated to MT_CKD v3.2, which has benefited from information from a range of laboratory studies relative to the model utilized in the previous ABSCO version. Impacts of these spectroscopy updates have been evaluated against ground-based atmospheric spectra from the Total Carbon Column Observing Network (TCCON) and within the framework of the OCO-2 algorithm, using OCO-2 soundings covering a range of atmospheric and surface conditions. The updated absorption coefficients (ABSCO version 5.1) are found to offer improved fitting residuals and reduced biases in retrieved surface pressure relative to the previous version (ABSCO v5.0) used within B8 and B9 of the OCO-2 retrieval algorithm and have been adopted for the OCO B10 Level 2 algorithm.

• Research Organization: Atmospheric and Environmental Research, Inc., Lexington, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institute of Standards and Technology (NIST); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: DEFG02-90ER610; FG02-90ER61064; FG02-90ER610
• OSTI ID: 1646512
• Alternate ID(s): OSTI ID: 1849995
• Journal Information: Journal of Quantitative Spectroscopy and Radiative Transfer, Journal Name: Journal of Quantitative Spectroscopy and Radiative Transfer Vol. 255 Journal Issue: C; ISSN 0022-4073
• Publisher: Elsevier
• Country of Publication: United Kingdom
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
oxygen
carbon dioxide
absorption
atmosphere
CIA
line-mixing