On the role of ozone feedback in the ENSO amplitude response under global warming

Peer J. Nowack, Peter Braesicke, N. Luke Abraham, John Pyle

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Abstract

The El Niño–Southern Oscillation (ENSO) in the tropical Pacific Ocean is of key importance to global climate and weather. However, state-of-the-art climate models still disagree on the ENSO's response under climate change. The potential role of atmospheric ozone changes in this context has not been explored before. Here we show that differences between typical model representations of ozone can have a first-order impact on ENSO amplitude projections in climate sensitivity simulations. The vertical temperature gradient of the tropical middle-to-upper troposphere adjusts to ozone changes in the upper troposphere and lower stratosphere, modifying the Walker circulation and consequently tropical Pacific surface temperature gradients. We show that neglecting ozone changes thus results in a significant increase in the number of extreme ENSO events in our model. Climate modeling studies of the ENSO often neglect changes in ozone. We therefore highlight the need to understand better the coupling between ozone, the tropospheric circulation, and climate variability.

Original languageEnglish
Pages (from-to)3858-3866
Number of pages9
JournalGeophysical Research Letters
Volume44
Issue number8
Early online date5 Apr 2017
DOIs
Publication statusPublished - 28 Apr 2017

Keywords

  • climate change
  • climate variability
  • ENSO
  • global warming
  • ozone
  • Walker circulation

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