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CCQM GAWG Ozone Cross-Section Task Group (GAWG-TG-Ozone)

Terms of reference

The Ozone Cross-Section Task Group is established by the CCQM GAWG, with the approval of the CCQM (April 2015), with the task of recommending a value and uncertainty for the ozone cross-section at 253.65 nm to be used in ozone reference photometers and for comparisons of these standards in BIPM.QM-K1.

The Chairs and Executive Secretary of the Task Group have been appointed by the GAWG, and members are drawn from the scientific community having published ozone cross-section data, statistics experts and GAWG experts. They are charged with:

  • Reviewing published papers on ozone cross-section measurements at 253.65 nm (see Annex 1), and preparing an assessment of the completeness of the uncertainty budget and any potential sources of bias in the measurements described and their impact on the published values;

  • Proposing possible approaches of combining the published measurement data, taking into account the outcome of the review, and recommending the approach which the Group believes results in the best estimate of the SI traceable value and uncertainty of the ozone cross-section value at 253.65 nm;

  • Preparing a paper summarizing the outputs of the Task Group and the recommended value and uncertainty for publication in a peer-reviewed journal;

  • Presenting the outputs of the Task Group to the CCQM-GAWG, including a recommendation for the value and uncertainty of the ozone absorption cross-section to be used in future rounds of the BIPM.QM-K1 comparison.


  • Dr Joseph Hodges  (NIST)


  • Dr Joële Viallon  (BIPM)


  • Prof. Paul Brewer  [NPL]
  • Dr Brian Drouin  [NASA JPL]
  • Dr Victor Gorshelev  [IUP]
  • Dr Christof Janssen  [LPMAA]
  • Dr Sangil Lee  [KRISS]
  • Dr Antonio Possolo  [NIST]
  • Dr Marie Ann Smith  [NASA Langley Research Center]
  • Dr Jari Walden  [FMI]
  • Dr Robert I. Wielgosz  [BIPM]

Designation of contact persons

  CCQM: Upcoming meetings
23–30 April 2021: 26th meeting of the CCQM and related meetings
22–29 April 2022: 27th meeting of the CCQM and related meetings

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