Atmospheric Chemistry and Physics (Jul 2025)
Global ground-based tropospheric ozone measurements: reference data and individual site trends (2000–2022) from the TOAR-II/HEGIFTOM project
- R. Van Malderen,
- A. M. Thompson,
- A. M. Thompson,
- D. E. Kollonige,
- D. E. Kollonige,
- R. M. Stauffer,
- H. G. J. Smit,
- E. Maillard Barras,
- C. Vigouroux,
- I. Petropavlovskikh,
- I. Petropavlovskikh,
- T. Leblanc,
- V. Thouret,
- P. Wolff,
- P. Effertz,
- P. Effertz,
- D. W. Tarasick,
- D. Poyraz,
- G. Ancellet,
- M.-R. De Backer,
- S. Evan,
- V. Flood,
- M. M. Frey,
- J. W. Hannigan,
- J. L. Hernandez,
- M. Iarlori,
- B. J. Johnson,
- N. Jones,
- R. Kivi,
- E. Mahieu,
- G. McConville,
- K. Müller,
- T. Nagahama,
- J. Notholt,
- A. Piters,
- N. Prats,
- R. Querel,
- D. Smale,
- W. Steinbrecht,
- K. Strong,
- R. Sussmann
Affiliations
- R. Van Malderen
- Royal Meteorological Institute of Belgium and Solar-Terrestrial Centre of Excellence, Uccle, Belgium
- A. M. Thompson
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- A. M. Thompson
- GESTAR, University of Maryland, Baltimore County, Baltimore, MD, USA
- D. E. Kollonige
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- D. E. Kollonige
- Science Systems and Applications, Inc, Lanham, MD, USA
- R. M. Stauffer
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- H. G. J. Smit
- Forschungszentrum Jülich, Jülich, Germany
- E. Maillard Barras
- Federal Office of Meteorology and Climatology MeteoSwiss, Payerne, Switzerland
- C. Vigouroux
- Royal Belgium Institute for Space Aeronomy, Uccle, Belgium
- I. Petropavlovskikh
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- I. Petropavlovskikh
- NOAA Global Monitoring Laboratory, Boulder, CO, USA
- T. Leblanc
- Jet Propulsion Laboratory, California Institute of Technology, Wrightwood, California, USA
- V. Thouret
- Laboratoire d'Aérologie, Université Toulouse III – Paul Sabatier, CNRS, Toulouse, France
- P. Wolff
- Observatoire Midi-Pyrénées, Université Toulouse III – Paul Sabatier, CNRS, Toulouse, France
- P. Effertz
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- P. Effertz
- NOAA Global Monitoring Laboratory, Boulder, CO, USA
- D. W. Tarasick
- Environment and Climate Change Canada, Downsview, ONT, Canada
- D. Poyraz
- Royal Meteorological Institute of Belgium and Solar-Terrestrial Centre of Excellence, Uccle, Belgium
- G. Ancellet
- LATMOS, Sorbonne Université, Université Versailles St-Quentin, CNRS/INSU, Paris, France
- M.-R. De Backer
- Groupe de Spectrométrie Moléculaire et Atmosphérique, Université de Reims, Reims, France
- S. Evan
- Laboratoire de l'Atmosphère et des Cyclones (LACy), CNRS, Université de La Réunion, Météo-France, Saint-Denis, France
- V. Flood
- Department of Physics, University of Toronto, Toronto, ON, Canada
- M. M. Frey
- IMKASF, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- J. W. Hannigan
- Atmospheric Chemistry, Observations & Modeling, National Center for Atmospheric Research, Boulder, CO, USA
- J. L. Hernandez
- State Meteorological Agency of Spain (AEMET), Madrid, Spain
- M. Iarlori
- CETEMPS Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, L'Aquila, Italy
- B. J. Johnson
- NOAA Global Monitoring Laboratory, Boulder, CO, USA
- N. Jones
- School of Physics, University of Wollongong, Wollongong, Australia
- R. Kivi
- Finnish Meteorological Institute, Space and Earth Observation Centre, Sodankylä, Finland
- E. Mahieu
- Institut d'Astrophysique et de Géophysique, Université de Liège, Liège, Belgium
- G. McConville
- NOAA Global Monitoring Laboratory, Boulder, CO, USA
- K. Müller
- Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research, Potsdam, Germany
- T. Nagahama
- Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
- J. Notholt
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- A. Piters
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
- N. Prats
- Izaña Atmospheric Research Center, State Meteorological Agency of Spain (AEMET), Santa Cruz de Tenerife, Spain
- R. Querel
- National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
- D. Smale
- National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
- W. Steinbrecht
- Deutscher Wetterdienst, Hohenpeissenberg, Germany
- K. Strong
- Department of Physics, University of Toronto, Toronto, ON, Canada
- R. Sussmann
- Karlsruhe Institute of Technology (KIT), IMK-IFU, Garmisch-Partenkirchen, Germany
- DOI
- https://doi.org/10.5194/acp-25-7187-2025
- Journal volume & issue
-
Vol. 25
pp. 7187 – 7225
Abstract
Tropospheric ozone trends from models and satellites are found to diverge. Ground-based (GB) observations are used to reference models and satellites, but GB data themselves might display station biases and discontinuities. Reprocessing with uniform procedures, the TOAR-II working group Harmonization and Evaluation of Ground-based Instruments for Free-Tropospheric Ozone Measurements (HEGIFTOM) homogenized public data from five networks: ozonesondes, In-service Aircraft for a Global Observing System (IAGOS) profiles, solar absorption Fourier transform infrared (FTIR) spectrometer measurements, lidar observations, and Dobson Umkehr data. Amounts and uncertainties for total tropospheric ozone (TrOC; surface to 300 hPa), as well as free- and lower-tropospheric ozone, are calculated for each network. We report trends (2000 to 2022) for these segments using quantile regression (QR) and multiple linear regression (MLR) for 55 datasets, including six multi-instrument stations. The findings are that (1) median TrOC trends computed with QR and MLR trends are essentially the same; (2) pole-to-pole, across all longitudes, TrOC trends fall within +3 to −3 ppbv per decade, equivalent to (−4 % to +8 %) per decade depending on site; (3) the greatest fractional increases occur over most tropical and subtropical sites, with decreases at northern high latitudes, but these patterns are not uniform; (4) post-COVID trends are smaller than pre-COVID trends for Northern Hemisphere mid-latitude sites. In summary, this analysis conducted in the frame of TOAR-II/HEGIFTOM shows that high-quality, multi-instrument, harmonized data over a wide range of ground sites provide clear standard references for TOAR-II models and evolving tropospheric ozone satellite products for 2000–2022.
