Comment on amt-2021-395

Abstract

Abstract. In this study, an extension on the previously reported status of the COllaborative Carbon Column Observing Network's (COCCON) calibration procedures incorporating refined methods is presented. COCCON is a global network of portable Bruker EM27/SUN FTIR spectrometers for deriving column-averaged atmospheric abundances of greenhouse gases. The original laboratory open-path lamp measurements for deriving the instrumental line shape (ILS) of the spectrometer from water vapour lines have been refined and extended to the secondary detector channel incorporated in the EM27/SUN spectrometer for detection of carbon monoxide (CO). The refinements encompass improved spectroscopic line lists for the relevant water lines and a revision of the laboratory pressure measurements used for the analysis of the spectra. The new results are found to be in good agreement with those reported by Frey et al. (2019) and discussed in detail. In addition, a new calibration cell for ILS measurements was designed, constructed and put into service. Spectrometers calibrated since January 2020 were tested using both methods for ILS characterization, open-path (OP) and cell measurements. We demonstrate that both methods can detect the small variations in ILS characteristics between different spectrometers, but the results of the cell method indicate a systematic bias of the OP method. Finally, a revision and extension of the COCCON network instrument-to-instrument calibration factors for XCO2, XCO and XCH4 is presented, incorporating 47 new spectrometers (of 83 in total by now). This calibration is based on the reference EM27/SUN spectrometer operated by the Karlsruhe Institute of Technology (KIT) and spectra collected by the collocated TCCON station Karlsruhe. Variations in the instrumental characteristics of the reference EM27/SUN from 2014 to 2017 were detected, probably arising from realignment and the dual-channel upgrade performed in early 2018. These variations are considered in the evaluation of the instrument-specific calibration factors in order to keep all tabulated calibration results consistent.

Authors 61

1. Carlos Alberti

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

2. Frank Hase

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

3. Matthias Frey

   National Institute for Environmental Studies

   Affiliation as printed

   National Institute for Environmental Studies (NIES), Tsukuba, Japan

4. Darko Dubravica

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

5. Thomas Blumenstock

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

6. Angelika Dehn

   European Space Agency · European Space Research Institute

   Affiliation as printed

   European Space Agency/Centre for Earth Observation (ESA/ESRIN), Frascati, Italy

7. Paolo Castracane

   European Space Agency · European Space Research Institute

   Affiliation as printed

   European Space Agency/Centre for Earth Observation (ESA/ESRIN), Frascati, Italy

8. Gregor Surawicz

   Bruker (Germany)

   Affiliation as printed

   Bruker Optics GmbH, Ettlingen, Germany

9. Roland Harig

   Bruker (Germany)

   Affiliation as printed

   Bruker Optics GmbH, Ettlingen, Germany

10. Bianca C. Baier

    National Oceanic and Atmospheric Administration · Cooperative Institute for Research in Environmental Sciences · University of Colorado Boulder · NOAA Global Monitoring Laboratory · NOAA Earth System Research Laboratory

    Affiliation as printed

    Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado-Boulder, Boulder, CO, USA

    Earth System Research Laboratory Global Monitoring Division, National Oceanic and Atmospheric Administration(NOAA), Boulder, CO, USA

11. Caroline BÃ ̈s

    Centre National d'Études Spatiales

    Affiliation as printed

    Centre National d'Etudes Spatiales (CNES), Paris, France​​​​​​​

12. Jianrong Bi

    Lanzhou University

    Affiliation as printed

    Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China​​​​​​​

13. Hartmut Boesch

    University of Leicester · National Centre for Earth Observation

    Affiliation as printed

    National Centre for Earth Observation, University of Leicester, Leicester, UK

14. André Butz

    Heidelberg University

    Affiliation as printed

    Institut für Umweltphysik, Universität Heidelberg, Heidelberg, Germany

15. Zhaonan Cai

    Chinese Academy of Sciences · Institute of Atmospheric Physics

    Affiliation as printed

    Carbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

16. Jia Chen

    Technical University of Munich

    Affiliation as printed

    Environmental Sensing and Modeling, Department of Electrical and Computer Engineering, Technische Universität München, Munich, Germany

17. Sean Crowell

    University of Oklahoma

    Affiliation as printed

    College of Atmospheric and Geographic Sciences, University of Oklahoma, Norman, OK, USA

18. Nicholas Michael Deutscher

    University of Wollongong

    Affiliation as printed

    Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, NSW, Australia​​​​​​​

19. Dragoș Ene

    National Institute of Research and Development for Optoelectronics

    Affiliation as printed

    National Institute of R&D for Optoelectronics INOE 2000, Măgurele, Ilfov, Romania

20. Jonathan E. Franklin

    Harvard University

    Affiliation as printed

    School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA

21. Omaira E. García

    Agencia Estatal de Meteorología

    Affiliation as printed

    Izaña Atmospheric Research Centre (IARC), State Meteorological Agency of Spain (AEMet), Santa Cruz de Tenerife, Spain

22. Bruno Grouiez

    Centre National de la Recherche Scientifique · Groupe de Spectrométrie Moléculaire et Atmosphérique · Université de Reims Champagne-Ardenne

    Affiliation as printed

    Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA), Université de Reims-Champagne Ardenne, UMR CNRS 7331, Moulin de la Housse, BP 1039, 51687 CEDEX 2 Reims, France

23. Michel Grutter

    Universidad Nacional Autónoma de México

    Affiliation as printed

    Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico

24. A. Hamdouni

    Centre National de la Recherche Scientifique · Groupe de Spectrométrie Moléculaire et Atmosphérique · Université de Reims Champagne-Ardenne

    Affiliation as printed

    Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA), Université de Reims-Champagne Ardenne, UMR CNRS 7331, Moulin de la Housse, BP 1039, 51687 CEDEX 2 Reims, France

25. Sander Houweling Aachen SRON Netherlands Institute for Space Research

    Space Research Organisation Netherlands · Vrije Universiteit Amsterdam

    Affiliation as printed

    Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands

    SRON Netherlands Institute for Space Research, Utrecht, the Netherlands

26. Neil Humpage

    University of Leicester · National Centre for Earth Observation

    Affiliation as printed

    National Centre for Earth Observation, University of Leicester, Leicester, UK

27. Nicole Jacobs

    University of Alaska Fairbanks · Cooperative Institute for Research in the Atmosphere · Colorado State University

    Affiliation as printed

    Cooperative Institute for Research in the Atmosphere (CIRA), Colorado State University, Fort Collins, CO, USA

    Department of Chemistry and the Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA

28. Sujong Jeong

    Seoul National University

    Affiliation as printed

    Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, Republic of Korea

29. Lilian Joly

    Centre National de la Recherche Scientifique · Groupe de Spectrométrie Moléculaire et Atmosphérique · Université de Reims Champagne-Ardenne

    Affiliation as printed

    Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA), Université de Reims-Champagne Ardenne, UMR CNRS 7331, Moulin de la Housse, BP 1039, 51687 CEDEX 2 Reims, France

30. Nicholas Brian Jones

    University of Wollongong

    Affiliation as printed

    Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, NSW, Australia​​​​​​​

31. D. Jouglet

    Centre National d'Études Spatiales

    Affiliation as printed

    Centre National d'Etudes Spatiales (CNES), Paris, France​​​​​​​

32. Rigel Kivi

    Finnish Meteorological Institute

    Affiliation as printed

    Space and Earth Observation Centre, Finnish Meteorological Institute, Sodankylä, Finland

33. Ralph Kleinschek

    Heidelberg University

    Affiliation as printed

    Institut für Umweltphysik, Universität Heidelberg, Heidelberg, Germany

34. Morgan Lopez

    Centre National de la Recherche Scientifique · Université de Versailles Saint-Quentin-en-Yvelines · Commissariat à l'Énergie Atomique et aux Énergies Alternatives · Université Paris-Saclay · Laboratoire des Sciences du Climat et de l'Environnement · CEA Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France

35. Diogo J. Medeiros

    Universidade de São Paulo

    Affiliation as printed

    Departamento de Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brazil

36. Isamu Morino

    National Institute for Environmental Studies

    Affiliation as printed

    National Institute for Environmental Studies (NIES), Tsukuba, Japan

37. Nasrin Mostafavi Pak

    University of Toronto

    Affiliation as printed

    Department of Physics, University of Toronto, Toronto, Canada

38. Astrid MÃ ⁄ ller

    National Institute for Environmental Studies

    Affiliation as printed

    National Institute for Environmental Studies (NIES), Tsukuba, Japan

39. Hirofumi Ohyama

    National Institute for Environmental Studies

    Affiliation as printed

    National Institute for Environmental Studies (NIES), Tsukuba, Japan

40. Paul I. Palmer

    University of Edinburgh

    Affiliation as printed

    National Centre for Earth Observation, University of Edinburgh, Edinburgh, UK

    School of GeoSciences, University of Edinburgh, Edinburgh, UK

41. Mahesh Pathakoti

    Indian Space Research Organisation · National Remote Sensing Centre

    Affiliation as printed

    Earth and Climate Sciences Area (ECSA), National Remote Sensing Centre (NRSC), ISRO, Hyderabad, India

42. David Frank Pollard

    National Institute of Water and Atmospheric Research

    Affiliation as printed

    National Institute of Water and Atmospheric Research Ltd (NIWA), Lauder, New Zealand

43. Uwe Raffalski

    Swedish Institute of Space Physics

    Affiliation as printed

    Swedish Institute of Space Physics, Kiruna, Sweden

44. Michel Ramonet

    Centre National de la Recherche Scientifique · Université de Versailles Saint-Quentin-en-Yvelines · Commissariat à l'Énergie Atomique et aux Énergies Alternatives · Université Paris-Saclay · Laboratoire des Sciences du Climat et de l'Environnement · CEA Paris-Saclay

    Affiliation as printed

    Université Paris-Saclay, CEA, CNRS, UVSQ, Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Gif-sur-Yvette, France

45. Robbie Ramsay

    Natural Environment Research Council · University of Edinburgh

    Affiliation as printed

    NERC Field Spectroscopy Facility, James Hutton Road, Edinburgh, EH9 3FE, UK

46. Mahesh Kumar Sha

    Royal Belgian Institute for Space Aeronomy

    Affiliation as printed

    Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium

47. Kei Shiomi

    Japan Aerospace Exploration Agency

    Affiliation as printed

    Earth Observation Research Center, Japan Aerospace Exploration Agency (JAXA), Tsukuba, Ibaraki, Japan

48. William Robert Simpson

    University of Alaska Fairbanks

    Affiliation as printed

    Department of Chemistry and the Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA

49. Wolfgang Stremme

    Universidad Nacional Autónoma de México

    Affiliation as printed

    Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico

50. Youwen Sun

    Chinese Academy of Sciences · Anhui Institute of Optics and Fine Mechanics

    Affiliation as printed

    Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China

51. Hiroshi Tanimoto

    National Institute for Environmental Studies

    Affiliation as printed

    National Institute for Environmental Studies (NIES), Tsukuba, Japan

52. Yao Té

    Sorbonne Université · Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères

    Affiliation as printed

    Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA-IPSL), Sorbonne Université, Paris, France

53. Gizaw Mengistu Tsidu

    Botswana International University of Science and Technology

    Affiliation as printed

    Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Palapye, Botswana​​​​​​​

54. Voltaire A. Velazco

    University of Wollongong

    Affiliation as printed

    Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, NSW, Australia​​​​​​​

55. Felix Vogel

    Environment and Climate Change Canada

    Affiliation as printed

    Climate Research Division, Environment and Climate Change Canada, Toronto, Canada

56. Masataka Watanabe

    Chuo University

    Affiliation as printed

    Research and Development Initiative, Chuo University, Bunkyo-ku, Tokyo, Japan

57. Chong Wei

    Chinese Academy of Sciences · Shanghai Advanced Research Institute

    Affiliation as printed

    Shanghai Carbon Data Research Center, Shanghai Advanced Research Institute (SARI), Chinese Academy of Sciences, Shanghai, China

58. Debra B. Wunch

    University of Toronto

    Affiliation as printed

    Department of Physics, University of Toronto, Toronto, Canada

59. Márcia Akemi Yamasoe

    Universidade de São Paulo

    Affiliation as printed

    Departamento de Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brazil

60. Lu Zhang

    China Meteorological Administration

    Affiliation as printed

    National Satellite Meteorological Center (NSMC), China Meteorological Administration, Beijing, China

61. J. Orphal

    Karlsruhe Institute of Technology

    Affiliation as printed

    Institute of Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

    now at: Division 4 “Natural and Built Environment”, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany