EGU21-157, updated on 03 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Observational evidence of solar activity interaction with chlorine chemistry curbing Antarctic ozone loss

Annika Seppälä1, Emily Gordon1,2, Bernd Funke3, Johanna Tamminen4, and Kaley Walker5
Annika Seppälä et al.
  • 1Department of Physics, University of Otago, Dunedin, New Zealand (
  • 2Now at Colorado State University, United States
  • 3Instituto de Astrofísica de Andalucía, Granada, Spain
  • 4Space and Earth Observation Centre, Finnish Meteorological Institute, Helsinki, Finland
  • 5Department of Physics, University of Toronto, Toronto, Canada

We present the impact of the so-called energetic particle precipitation (EPP), part of natural solar forcing on the atmosphere, on polar stratospheric NOx, ozone, and chlorine chemistry in the Antarctic springtime, using multi-satellite observations covering the overall period of 2005–2017. We find consistent ozone increases when high solar activity occurs during years with easterly phase of the quasi biennial oscillation. These ozone enhancements are also present in total O3 column observations. We find consistent decreases in springtime active chlorine following winters of elevated solar activity. Further analysis shows that this is accompanied by increase of chemically inactive chlorine reservoir species, explaining the observed ozone increase. This provides the first observational evidence supporting the previously proposed mechanism relating to EPP modulating chlorine driven ozone loss. Our findings suggest that solar activity via EPP has played an important role in modulating Antarctic ozone depletion in the last 15 years. As chlorine loading in the polar stratosphere continues to decrease in the future, this buffering mechanism will become less effective and catalytic ozone destruction by EPP produced NOx will likely become a major contributor to Antarctic ozone loss.

How to cite: Seppälä, A., Gordon, E., Funke, B., Tamminen, J., and Walker, K.: Observational evidence of solar activity interaction with chlorine chemistry curbing Antarctic ozone loss, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-157,, 2020.

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