14 Mar 2022
14 Mar 2022
Status: a revised version of this preprint was accepted for the journal ACP.

Updated trends of the stratospheric ozone vertical distribution in the 60° S–60° N latitude range based on the LOTUS regression model

Sophie Godin-Beekmann1, Niramson Azouz1, Viktoria Sofieva2, Daan Hubert3, Irina Petropavlovskikh4, Peter Effertz4, Gérard Ancellet1, Douglas Degenstein5, Daniel Zawada5, Lucien Froidevaux6, Stacey Frith7, Jeannette Wild8, Sean Davis9, Wolfgang Steinbrecht10, Thierry Leblanc11, Richard Querel12, Kleareti Tourpali13, Robert Damadeo14, Eliane Maillard-Barras15, René Stübi15, Corinne Vigouroux3, Carlo Arosio16, Gerald Nedoluha17, Ian Boyd18, and Roeland van Malderen19 Sophie Godin-Beekmann et al.
  • 1LATMOS Sorbonne Université, UVSQ, CNRS, France
  • 2Finish Meteorological Institute, Finland
  • 3Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Belgium
  • 4Cooperative Institute for Research in Environmental Sciences, U. of Colorado, Boulder, CO, USA
  • 5University of Saskatchewan, Canada
  • 6Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA
  • 7Science Systems and Applications, Inc &NASA Goddard Space Flight Center, USA
  • 8ESSIC/UMD & NOAA/NCEP/Climate Prediction Center, USA
  • 9NOAA Chemical Sciences Laboratory, USA
  • 10Deutsche Wetterdienst, Germany
  • 11Jet Propulsion Laboratory, California Institute of Technology, Wrightwood, USA
  • 12National Institute of Water and Atmospheric Research (NIWA), New Zealand
  • 13Aristotle University of Thessaloniki, Greece
  • 14NASA Langley, USA
  • 15Federal Office of Meteorology and Climatology, MeteoSwiss, Switzerland
  • 16Institute of Environmental Physics,Bremen Universität, Germany
  • 17Remote Sensing Division, Naval Research Laboratory, Washington, DC, USA
  • 18Bryan Scientific Consulting, Charlottesville, VA, USA
  • 19Royal Meteorological Institute, Belgium

Abstract. This study presents an updated evaluation of stratospheric ozone profile trends in the 60° S–60° N latitude range over the 2000–2020 period, using an updated version of the Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS) regression model that was used to evaluate such trends up to 2016 for the last WMO Ozone Assessment (2018). In addition to the derivation of detailed trends as a function of latitude and vertical coordinates, the regressions are performed with the data sets averaged over broad latitude bands, i.e. 60° S–35° S, 20° S–20° N and 35° N–60° N. The same methodology as in the last Assessment is applied to combine trends in these broad latitude bands in order to compare the results with the previous studies. Longitudinally resolved merged satellite records are also considered in order to provide a better comparison with trends retrieved from ground-based records, e.g. lidar, ozone sondes, Umkehr, microwave and Fourier Transform Infrared (FTIR) spectrometers at selected stations where long-term time series are available. The study includes a comparison with trends derived from the latest REF-C2 simulations of the Chemistry Climate Model Initiative (CCMI). This work confirms past results showing an ozone increase in the upper stratosphere, which is now significant in the three broad latitude bands. The increase is largest in the northern and southern hemisphere midlatitudes, with ~2.2 %/decade at ~2.1 hPa, and ~2.1 %/decade at ~3.2 hPa respectively, compared to ~1.6 %/decade at ~2.6 hPa in the tropics. New trend signals have emerged from the records, such as a significant decrease of ozone in the tropics around 35 hPa and a non-significant increase of ozone in the southern mid-latitudes at about 20 hPa. Non-significant negative ozone trends are derived in the lowermost stratosphere, with the most pronounced trends in the tropics. While a very good agreement is obtained between trends from merged satellite records and the CCMI REF-C2 simulation in the upper stratosphere, observed negative trends in the lower stratosphere are not reproduced by models at southern and, in particular, at northern midlatitudes, where models report an ozone increase. However, the lower stratospheric trend uncertainties are quite large, for both measured and modelled trends. Finally, 2000–2020 stratospheric ozone trends derived from the ground-based and longitudinally resolved satellite records are in close agreement, especially over the European Alpine and tropical regions.

Sophie Godin-Beekmann et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2022-137', Anonymous Referee #1, 03 Apr 2022
  • RC2: 'Comment on acp-2022-137', Anonymous Referee #2, 04 Apr 2022
  • CC1: 'Comment on acp-2022-137 regarding proper acknowledgment of data sets', Emmanuel Mahieu, 19 Apr 2022
    • AC3: 'Reply on CC1', Sophie Godin-Beekmann, 05 May 2022

Sophie Godin-Beekmann et al.

Sophie Godin-Beekmann et al.


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Short summary
An updated evaluation of stratospheric ozone profile long-term trends at extrapolar latitudes up to 2020 is presented. Ozone increase in the upper stratosphere is confirmed, with significant trends in most latitude bands. In this altitude region, a very good agreement is observed with trends derived from chemistry climate model simulations. Observed and modeled trends diverge in the lower stratosphere but the differences are non-significant due to large uncertainties.