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Reevaluation of total-column ozone trends and of the Effective Radiative Forcing of ozone-depleting substances
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  • Olaf Morgenstern,
  • Stacey M Frith,
  • Gregory Elton Bodeker,
  • Vitali Fioletov,
  • Dr. Ronald Vander A
Olaf Morgenstern

Corresponding Author:olaf.morgenstern@niwa.co.nz

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Stacey M Frith
Science Systems and Applications, Inc.
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Gregory Elton Bodeker
Bodeker Scientific Ltd.
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Vitali Fioletov
Environment and Climate Change Canada
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Dr. Ronald Vander A
Climate Observations KNMI (Royal Netherlands Meteorological Institute,Netherlands
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We evaluate total-column ozone trends using a piecewise linear regression approach and maximizing usage of five gridded total-column ozone datasets. The new approach yields more consistent estimates of observed ozone loss during 1979-2000, when halocarbon concentrations were increasing, and consequently, using CMIP6 simulations, an increased Effective Radiative Forcing estimate of ozone-depleting substances with a substantially reduced uncertainty range versus an earlier evaluation. At more than 84% confidence it is now larger than zero and compares more favorably with two previous evaluations. We furthermore find significant, positive post-1997 global- and Southern-Hemisphere mean trends, respectively, in these four datasets. For the extrapolar region (60S-60N) and for the Northern Hemisphere, the assessment whether there is a positive trend is inconclusive and depends on which observational dataset is included in the calculation.
16 Nov 2021Published in Geophysical Research Letters volume 48 issue 21. 10.1029/2021GL095376