CaltechAUTHORS
Published May 6, 2024 | Version Published
Journal Article Open

The Total Carbon Column Observing Network's GGG2020 data version

Creators

  • 1. ROR icon Jet Propulsion Lab
  • 2. ROR icon Environment and Climate Change Canada
  • 3. ROR icon University of Bremen
  • 4. ROR icon Harvard University
  • 5. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 6. ROR icon University of Toronto
  • 7. ROR icon University of Wollongong
  • 8. ROR icon Finnish Meteorological Institute
  • 9. ROR icon Scripps Research Institute
  • 10. ROR icon California Institute of Technology
  • 11. Earth Observing Laboratory, National Center for Atmospheric Research (NCAR), Boulder, CO, USA
  • 12. ROR icon Earth System Research Laboratory
  • 13. ROR icon University of Groningen
  • 14. ROR icon Nanjing University
  • 15. ROR icon Langley Research Center
  • 16. Analytical Mechanics Associated, Hampton, VA 23666, USA
  • 17. ROR icon Karlsruhe Institute of Technology
  • 18. Laboratoire d'Études du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA-IPSL), Sorbonne Université, CNRS, Observatoire de Paris, PSL Université, 75005 Paris, France
  • 19. ROR icon University of Paris-Saclay
  • 20. ROR icon University of Bern
  • 21. ROR icon Cooperative Institute for Research in Environmental Sciences
  • 22. ROR icon National Institute for Environmental Studies
  • 23. ROR icon National Institute of Water and Atmospheric Research
  • 24. NASA Earth Science Technology Office (ESTO), B22, 242, 8800 Greenbelt Rd., Greenbelt, MD 20771, USA
  • 25. ROR icon Cyprus Institute
  • 26. ROR icon Royal Belgian Institute for Space Aeronomy
  • 27. ROR icon Japan Aerospace Exploration Agency
  • 28. ROR icon German Meteorological Service
  • 29. ROR icon Institute of Atmospheric Physics

Abstract

The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs), beginning in 2004, from over 30 current or past measurement sites around the world using solar absorption spectroscopy in the near-infrared (near-IR) region. TCCON GHG data have been used extensively for multiple purposes, including in studies of the carbon cycle and anthropogenic emissions, as well as to validate and improve observations from space-based sensors. Here, we describe an update to the retrieval algorithm used to process the TCCON near-IR solar spectra and to generate the associated data products. This version, called GGG2020, was initially released in April 2022. It includes updates and improvements to all steps of the retrieval, including but not limited to the conversion of the original interferograms into spectra, the spectroscopic information used in the column retrieval, post hoc air mass dependence correction, and scaling to align with the calibration scales of in situ GHG measurements.

Copyright and License

© Author(s) 2024. This work is distributed under the Creative Commons Attribution 4.0 License. Published by Copernicus Publications.

Acknowledgement

The authors gratefully acknowledge the use of GNU Parallel (Tange, 2011) in the GGG processing. The authors also thank James Abshire for providing the CO2 data used in deriving the in situ correction (Sect. 8.3). A portion of this research was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with NASA (80NM0018D0004). Government sponsorship is acknowledged. Support for Caltech TCCON sites and partial support for Joshua L. Laughner, Matthäus Kiel, Coleen M. Roehl, and Paul O. Wennberg were provided by NASA grants NNX17AE15G and 80NSSC22K1066. Material from Britton B. Stephens and Ralph F. Keeling is based upon work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement No. 1852977.

Markus Rettinger and Ralf Sussmann acknowledge funding by the German Helmholtz Research Program “Changing Earth – Sustaining our Future” within the Research Field “Earth and Environment”. The Paris TCCON site has received funding from Sorbonne Université, the French research center CNRS, and the French space agency CNES. The Cyprus TCCON site and AirCore flights have received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 856612 and from the Cyprus Government. The TCCON site at Réunion Island has been operated by the Royal Belgian Institute for Space Aeronomy with financial support since 2014 by the EU project ICOS-INIWRE (grant agreement no. 313169), the ministerial decree for ICOS (grant nos. FR/35/IC1 to FR/35/C6), the ESFRI-FED ICOS-BE project (grant no. EF/211/ICOS-BE), and local activities supported by LACy/UMR8105 and by OSU-R/UMS3365 – Université de La Réunion. The Eureka TCCON measurements were made at the Polar Environment Atmospheric Research Laboratory (PEARL) by the Canadian Network for the Detection of Atmospheric Change (CANDAC), primarily supported by the Natural Sciences and Engineering Research Council of Canada, Environment and Climate Change Canada, and the Canadian Space Agency. TCCON sites at Tsukuba, Rikubetsu, and Burgos are supported in part by the GOSAT series project. Burgos is supported in part by the Energy Development Corporation Philippines.

Funding

This research has been supported by the National Aeronautics and Space Administration (contract no. 80NM0018D0004, grant nos. NNX17AE15G, and 80NSSC22K1066), the Horizon 2020 (grant no. EMME-CARE – Eastern Mediterranean and Middle East – Climate and Atmosphere Research Centre (856612)), the Seventh Framework Programme FP7 Cooperation (grant no. 313169), and the Belgian Federal Science Policy Office (grant nos. FR/35/IC1 to FR/35/C6 and EF/211/ICOS-BE).

Data Availability

All TCCON GGG2020 data are linked through https://tccondata.org (last access: 22 April 2024) and stored as DOI-tagged data sets on CaltechDATA (https://data.caltech.edu, last access: 22 April 2024). Each TCCON site has a separate repository and DOI on CaltechDATA; these are listed in Table 2. If a future correction requires a revision of previously published data, that revision will receive a new DOI. Users are encouraged to check https://tccondata.org for the latest revisions of data rather than relying on Table 2. A repository containing the full set of TCCON GGG2020 data is also available on CaltechDATA with the DOI https://doi.org/10.14291/TCCON.GGG2020 (Total Carbon Column Observing Network (TCCON) Team, 2022). Users are asked to cite the individual sites' data records rather than the combined record as this helps track usage of site data and thus support the ongoing operation of these sites. We provide a citation generator at https://tccondata.org/metadata/siteinfo/genbib/ (last access: 22 April 2024). All data are provided in netCDF format, and additional documentation for the data is available at https://tccon-wiki.caltech.edu/ The TCCON community, 2024. The GGG2020 retrieval software is archived on CaltechDATA (https://doi.org/10.14291/tccon.ggg2020.stable.R0, Toon, 2023), as well as being publicly available through GitHub at https://github.com/TCCON/GGG (last access: 11 July 2023).

Additional Information

This paper was edited by David Carlson and reviewed by Denis Jouglet, Gretchen Keppel-Aleks, and one anonymous referee.

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Additional details

Related works

Is new version of
Discussion Paper: 10.5194/essd-2023-331 (DOI)
Is supplemented by
Dataset: 10.14291/TCCON.GGG2020 (DOI)
Dataset: 10.14291/tccon.ggg2020.stable.R0 (DOI)
Software: https://github.com/TCCON/GGG (URL)

Funding

National Aeronautics and Space Administration
80NM0018D0004
National Aeronautics and Space Administration
NNX17AE15G
National Aeronautics and Space Administration
80NSSC22K1066
European Research Council
856612
FP7 Cooperation
313169
Belgian Federal Science Policy Office
FR/35/IC1
Belgian Federal Science Policy Office
FR/35/C6
Belgian Federal Science Policy Office
EF/211/ICOS-BE

Dates

Accepted
2024-02-29

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Caltech groups
Division of Engineering and Applied Science (EAS), Division of Geological and Planetary Sciences (GPS)
Publication Status
Published