ET‐ACDM 2025‐5: 2 December 2025 - wmo-im/et-acdm GitHub Wiki

Date and Time

2 December 2025 12:00 UTC (13:00 CET)

Venue

telecon

Attendance

Jörg Klausen, Judd Welton, Markus Fiebig, Debra Kollonige, Alex Vermeulen, Kaisa Lakkala, Gao Chen, Kentaro Ishijima, Lingaona Zhu (Secretariat), Sergi Moreno (Secretariat)

Agenda

1. Welcome and approval of minutes from previous meeting

Notes from last meeting approved.

2. GAW updates from Secretariat

No major updates from Secretariat but the reorganisation of the GAW Programme, see point 4.

3. Developing GAW dashboard: feedback from ET-ACDM to the list of GAW variables & csv description

Current status and feedback received

  • Comments from Kentaro (WDCGG) received. Other member's suggestions are welcomed.

  • Project awaiting for Copernicus signature.

Comments on the list of variables

  • Objections to mole fraction: discussion between 'mole fraction' more widely used (for example by GCOS) or 'amount fraction' which does not include a unit (mole); cf. https://doi.org/10.1351/goldbook.A00296.

  • Suggestion to specify column: content or height and to change unit, ppm is an amount not a column unit. Gas column concentration unit is ppm.m. Total column observations are usually expressed as column-averaged dry-air mole fraction (XCO2, ...)

  • Suggestion to link the variables to those in the WMO code registry and follow the discussion in WMO ET-Metadata's github forum.

  • Discussion about the inclusion of H2: emerging variable and indirect GHG.

  • Scrutiny needed between objects of interests vs observed variables.

  • Suggestion to include NOx and NO.

  • Discussion about particle light scattering (23 and 24) surface and profile, should it be named differently?

  • Question on AOD, why we name it aerosol if the rest are particle light? Particle light extinction optical depth suggested.

  • Particle light scattering is a process, not an observable variable.

  • Discussion about what is preferable: using widely recognized terms (PM, AOD) or more precise descriptions such as particle light extinction. Are we aiming to align with general understanding, or are we educating the general public?

  • Suggestion to expand the list - however, it is the first version and must be short to allow testing process and not overload the systems.

  • Suggestion to create github sub-issues for each topic: aerosols, VOCs...

Comments on csv description

  • Comment on the wavelength been put into a separate section without format, suggestion to constraint the possible entries to help data identification/extraction.

4. Feedback from ET-ACDM to GAW reorganisation proposal GAW reorganized proposal slides, GAW Reorganization Document with Questions

  • Suggestion to look at the number of tasks/services GAW wish to achieve or deliver and then balance them with the expected resources.

  • Suggestion to relocate measurement quality to SAGs where the expertise to measure a variable must be.

  • Comment on the difficulties the SAGs can face while dealing with network design, tiered networks concept, or issues relate to the GAW Central Facilities.

  • Question on GAW mandate: to provide high quality data or to facilitate the use of that data? Or, both?

  • Questions on the large scope of an ET dealing with calibration and data management. Regional activities should not be an ET on its own.

  • Suggestion to have a less rigid structure and make it more fluid and focused on tasks, time-bound and well-scoped.

  • Suggestion to have a pool of experts, larger than the current cohort of experts in GAW groups, and then organise WG focus on specific projects. Still keeping a core group (SAGs?).

  • Issues with the interaction of SAGs with Expert Teams due to the composition of SAGs or lack of communication (SAG-ET) or lack of predefined relation (SAG-ET).

  • Suggestion for a better communication between all the groups and in particular from SSC-EPAC with the rest.

5. Discussion about KPIs postponed

Update from Secretariat:

  • Agreement to receive data every 3 months. Microsoft Power BI will be used.

  • Option 1: Excel or csv file format. WMO will do the rest.

  • Option 2: If you have database in SQL, can WDCs enable access to WMO via connection string or API?

Action: WDCs to choose Option 1 or 2

6. Contingency plans for atmospheric composition data

https://github.com/wmo-im/et-acdm/issues/27

7. AOB, next meeting

Jörg asked for volunteers to contribute to the evolution of the WIGOS metadata representation. The idea is to simplify the current one while retaining its potential, and to properly specify it, similar to WIS2, and/or an OGC/ISO standard.

Action: To contact Jörg if you want to participate in preparing the standard

Next ET-ACDM meeting 22 January 2026