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Arctic ozone depletion in 2019/20: Roles of chemistry, dynamics and the Montreal Protocol
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  • Wuhu Feng,
  • Sandip Dhmose,
  • Carlo Arosio,
  • Mark Weber,
  • John P Burrows,
  • Michelle L. Santee,
  • Martyn P. Chipperfield
Wuhu Feng
University of Leeds
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Sandip Dhmose
School of Earth and Environment

Corresponding Author:[email protected]

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Carlo Arosio
IUP - Unibremen
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Mark Weber
University of Bremen FB1
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John P Burrows
University of Bremen
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Michelle L. Santee
Jet Propulsion Laboratory
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Martyn P. Chipperfield
University of Leeds
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Abstract

We use a 3-D chemical transport model and satellite observations to investigate Arctic ozone depletion in winter/spring 2019/20 and compare with earlier years. Persistently low temperatures caused extensive chlorine activation through to March. March-mean polar-cap-mean modelled chemical column ozone loss reached 78 DU (local maximum loss of ~108 DU in the vortex), similar to that in 2011. However, weak dynamical replenishment of only 59 DU from December to March was key to producing very low (<220 DU) column ozone values. The only other winter to exhibit such weak transport in the past 20 years was 2010/11, so this process is fundamental to causing such low ozone values. A model simulation with peak observed stratospheric total chlorine and bromine loading (from the mid-1990s) shows that gradual recovery of the ozone layer over the past two decades ameliorated the polar cap ozone depletion in March 2020 by ~20 DU.
28 Feb 2021Published in Geophysical Research Letters volume 48 issue 4. 10.1029/2020GL091911