HEGIFTOM Focus Working Group
Working Group leads: Roeland Van Malderen, RMI, Belgium (roeland @ meteo.be)
Herman G.J. Smit, Forschungszentrum Juelich, Germany (h.smit @ fz-juelich.de)
TOAR-II Steering Committee liaison: Gabi Pfister, National Center for Atmospheric Research, Boulder, USA (pfister @ ucar.edu)
Established: October 13, 2020
The Harmonization and Evaluation of Ground Based Instruments for Free Tropospheric Ozone Measurements (HEGIFTOM) Focus Working Group has the following objectives:
Although tropospheric ozone monitoring has evolved from sporadic measurements at a few locations to extensive, well-calibrated networks with formal international collaboration, as well as global satellite observations, it is not comprehensive. Each method of observation has its inherent advantages and limitations, and the different techniques will continue to complement and support each other. In this context, international cooperation and data sharing will be of paramount importance. However, there is currently a need for a comprehensive intercomparison and homogenization of tropospheric ozone measurement methods and the datasets produced by them. The working group will bring together different networks of ground-based instruments measuring free tropospheric ozone, not only to strengthen, speed up, and expand existing activities of harmonization of instruments, but also to compare Quality Assurance/Quality Control (QA/QC) procedures and reports, and harmonization efforts between the different networks. Moreover, at dedicated sites or for identical air masses (in case of e.g. ozonesondes and aircraft measurements), the data themselves and their associated uncertainties will be cross-compared between different techniques. The major deliverable will be quality-assessed ozone datasets for which each measurement has an uncertainty and a quality flag. Instrumental bias, bias drifts and representativeness uncertainty will also be characterized, evaluated and documented. The working group will include both well-established techniques and developing strategies for tropospheric ozone retrieval (MAX-DOAS, Pandora, etc).