Uncertainties in recent tropical stratospheric and tropospheric ozone changes restrict our understanding of future total column ozone change
Abstract. A variety of chemical and dynamical processes in the troposphere and stratosphere affect tropical total column ozone (TCO), the net effect of which may cause changes in surface UV radiation and impact human and ecosystem health. We use dynamical linear modeling to estimate tropical trends in TCO and partial column ozone (PCO) in the troposphere and three stratospheric layers to assess agreement between satellite observational composites and chemistry–climate model (CCM) simulations from two multi-model experiments (CCMI-1 and CCMI-2022). While both model experiments show tropical TCO increases over 2000–2021, CCMI–2022 trends (+2.5 DU) agree slightly better with observations than CCMI-1 (+1.6 DU). However, this overall agreement obscures multiple systematic differences in PCO trends between the models and observations across atmospheric layers. For example, since 2000 tropical tropospheric PCO increased significantly in CCMI-2022 (+1.5 DU) but not in CCMI–1 (+0.3 DU), largely explaining the difference in TCO trends. Also, despite nearly identical stratospheric PCO trends, CCMI-2022 trends are slightly more negative in the lower stratospheric (by ~0.5 DU), compensated by more positive middle/upper stratosphere trends compared to CCMI-1. Crucially, substantial differences exist across observational PCO trends, particularly in the troposphere and middle/upper stratosphere, and these disagreements limit the ability to evaluate CCM fidelity. Furthermore, while the inter-model correlation between late and early 21st century trends is suggestive of a potential emergent constraint on future ozone trends, the spread in observational trends precludes its observational implementation.
Authors
- Carlo Arosio (ORCID: https://orcid.org/0000-0002-8759-6390)
- R. W. Portmann (ORCID: https://orcid.org/0000-0002-0279-6087)
- Diego Loyola (ORCID: https://orcid.org/0000-0002-8547-9350)
- Olaf Morgenstern (ORCID: https://orcid.org/0000-0002-9967-9740)
- D. A. Plummer
- Sean M. Davis (ORCID: https://orcid.org/0000-0001-9276-6158)
- Hideharu Akiyoshi (ORCID: https://orcid.org/0000-0001-6463-9004)
- James M. Keeble (ORCID: https://orcid.org/0000-0003-2714-1084)
- William T. Ball (ORCID: https://orcid.org/0000-0002-1005-3670)
- Mohamadou Diallo (ORCID: https://orcid.org/0000-0003-0225-8120)
- Ronald Johannes Van Der A
- M. Marchand
- Viktoria Sofieva (ORCID: https://orcid.org/0000-0002-9192-2208)
- J. Staehelin
- Gabriel Chiodo (ORCID: https://orcid.org/0000-0002-8079-6314)
- Andreas Chrysanthou (ORCID: https://orcid.org/0000-0002-8670-5436)
- Melanie Coldewey‐Egbers (ORCID: https://orcid.org/0000-0002-9275-498X)
- N. A. Kramarova (ORCID: https://orcid.org/0000-0002-6083-8548)
- Jeannette Wild
- Krzysztof Wargan (ORCID: https://orcid.org/0000-0002-3795-2983)
- Roland Eichinger (ORCID: https://orcid.org/0000-0001-6872-5700)
- Justin Alsing (ORCID: https://orcid.org/0000-0003-4618-3546)
- Birgit Haßler (ORCID: https://orcid.org/0000-0003-2724-709X)
- Robert Damadeo (ORCID: https://orcid.org/0000-0002-1466-839X)
- Patrick Jöckel
- Daan Hubert
- Béatrice Josse
- Eliane Maillard Barras
- Kleareti Tourpali
- Yue Jia
- Yousuke Yamashita
- Mark Weber
- Simone Dietmüller
- H. J. Ray Wang
- Sandip Dhomse
- Shingo Watanabe
- Stacey Frith
- Alexei Rozanov
- Jerry Ziemke
- Timofei Sukhodolov
- Ewa M. Bednarz
- Michaela Hegglin
- Karen Rosenlof
Institutions
- Finnish Meteorological Institute (FI)
- Centre National de la Recherche Scientifique (FR)
- Goddard Space Flight Center (US)
- Georgia Institute of Technology (US)
- University of Leeds (GB)
- Royal Netherlands Meteorological Institute (NL)
- Japan Agency for Marine-Earth Science and Technology (JP)
- Langley Research Center (US)
- Environment and Climate Change Canada (CA)
- Stockholm University (SE)
- Cooperative Institute for Research in Environmental Sciences (US)
- The University of Texas at Dallas (US)
- University of Wuppertal (DE)
- Forschungszentrum Jülich (DE)
- Deutscher Wetterdienst (DE)
- Université Fédérale de Toulouse Midi-Pyrénées (FR)
- University of Bremen (DE)
- University of Canterbury (NZ)
- Université de Versailles Saint-Quentin-en-Yvelines (FR)
- Royal Belgian Institute for Space Aeronomy (BE)
- National Institute for Environmental Studies (JP)
- Tohoku University (JP)
- Charles University (CZ)
- Aristotle University of Thessaloniki (GR)
- Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE)
- ETH Zurich (CH)
- Sorbonne Université (FR)
- Météo-France (FR)
- Institut Pierre-Simon Laplace (FR)
- Physikalisch-Meteorologisches Observatorium Davos (CH)
- National Centre for Earth Observation (GB)
- NOAA Chemical Sciences Laboratory (US)
- NOAA Center for Satellite Applications and Research (US)
- Science Systems and Applications (United States) (US)
- Instituto de Geociencias (ES)
- Laboratoire atmosphères, milieux, observations spatiales (FR)
- Adnet Systems (United States) (US)
- National Institute of Water and Atmospheric Research (NZ)
- Lancaster University (GB)
- University of Reading (GB)
- Morgan State University (US)
- University of North Texas at Dallas (US)
- Delft University of Technology (NL)
Publication Details
- Published
- 2026-02-26
- DOI
- https://doi.org/10.5194/egusphere-2026-532
- Primary Topic
- Atmospheric Ozone and Climate
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Deutsches Zentrum für Luft- und Raumfahrt
- National Oceanic and Atmospheric Administration
- Japan Society for the Promotion of Science