Atmospheric Chemistry and Physics (Sep 2025)
Ground-based tropospheric ozone measurements: regional tropospheric ozone column trends from the TOAR-II/HEGIFTOM homogenized datasets
- R. Van Malderen,
- Z. Zang,
- K.-L. Chang,
- K.-L. Chang,
- R. Björklund,
- O. R. Cooper,
- J. Liu,
- E. Maillard Barras,
- C. Vigouroux,
- I. Petropavlovskikh,
- I. Petropavlovskikh,
- T. Leblanc,
- V. Thouret,
- P. Wolff,
- P. Effertz,
- P. Effertz,
- A. Gaudel,
- A. Gaudel,
- D. W. Tarasick,
- H. G. J. Smit,
- A. M. Thompson,
- A. M. Thompson,
- R. M. Stauffer,
- D. E. Kollonige,
- D. E. Kollonige,
- D. Poyraz,
- G. Ancellet,
- M.-R. De Backer,
- M. M. Frey,
- J. W. Hannigan,
- J. L. Hernandez,
- B. J. Johnson,
- N. Jones,
- R. Kivi,
- E. Mahieu,
- I. Morino,
- G. McConville,
- K. Müller,
- I. Murata,
- J. Notholt,
- A. Piters,
- M. Prignon,
- R. Querel,
- V. Rizi,
- 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
- Z. Zang
- Department of Geography and Planning, University of Toronto, Toronto, Canada
- K.-L. Chang
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- K.-L. Chang
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
- R. Björklund
- Royal Belgian Institute for Space Aeronomy, Uccle, Belgium
- O. R. Cooper
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
- J. Liu
- Department of Geography and Planning, University of Toronto, Toronto, Canada
- E. Maillard Barras
- Federal Office of Meteorology and Climatology MeteoSwiss, Payerne, Switzerland
- C. Vigouroux
- Royal Belgian 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
- A. Gaudel
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- A. Gaudel
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
- D. W. Tarasick
- Environment and Climate Change Canada, Downsview, ON, Canada
- H. G. J. Smit
- Institute of Climate and Energy Systems 3: Troposphere (ICE-3), Forschungszentrum Jülich (FZJ), Jülich, Germany
- 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
- R. M. Stauffer
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, 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
- 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
- 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
- Spanish Meteorological Agency (AEMET), Madrid, Spain
- 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
- I. Morino
- Earth System Division, National Institute for Environmental Studies, Tsukuba, Japan
- G. McConville
- NOAA Global Monitoring Laboratory, Boulder, CO, USA
- K. Müller
- Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research, Potsdam, Germany
- I. Murata
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
- J. Notholt
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
- A. Piters
- Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
- M. Prignon
- Space Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden
- R. Querel
- National Institute of Water and Atmospheric Research (NIWA), Lauder, New Zealand
- V. Rizi
- CETEMPS Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, L'Aquila, Italy
- 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-25-9905-2025
- Journal volume & issue
-
Vol. 25
pp. 9905 – 9935
Abstract
Quantifying long-term free-tropospheric ozone trends is essential for understanding the impact of human activities and climate change on atmospheric chemistry. However, this is complicated by two key challenges: the differences among existing satellite-derived tropospheric ozone products, which are not yet fully understood or reconciled, and the limited temporal and spatial coverage of ground-based reference measurements. Here, we explore if a more consistent understanding of the geographical distribution of tropospheric ozone column (TrOC) trends can be obtained by focusing on regional trends from ground-based measurements. Regions were determined with a correlation analysis between modeled TrOCs at the site locations. For those regions, TrOC trends were estimated with quantile regression for the Trajectory-mapped Ozonesonde dataset for the Stratosphere and Troposphere (TOST) and with a linear mixed-effects modeling (LMM) approach to calculate synthesized trends from homogenized HEGIFTOM (Harmonization and Evaluation of Ground-based Instruments for Free-Tropospheric Ozone Measurements) individual site trends. For different periods (1990–2021/22, 1995–2021/22, 2000–2021/22), both approaches give increasing (partial) tropospheric ozone column amounts over almost all Asian regions (median confidence) and negative trends over Arctic regions (very high confidence). Trends over Europe and North America are mostly weakly positive (LMM) or negative (TOST). For both approaches, the 2000–2021/22 trends decreased in magnitude compared to 1995–2021/22 for most regions; and for all time periods and regions, the pre-COVID trends are larger than the post-COVID trends. Our results enable the validation of global satellite TrOC trends and assessment of the performance of atmospheric chemistry models to represent the distribution and variation of TrOC.
