EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impact of sub-seasonal atmosphere-ocean interactions in a large ensemble

Matthias Aengenheyster1, Sarah Sparrow2, Peter Watson3, David Wallom2, Laure Zanna1,5, and Myles Allen1,4
Matthias Aengenheyster et al.
  • 1Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, UK
  • 2Oxford e-Research Centre, University of Oxford, UK
  • 3School of Geographical Sciences, University of Bristol, Bristol, UK
  • 4Environmental Change Institute, University of Oxford, Oxford, UK
  • 5Courant Institute of Mathematical Sciences, New York University, New York, USA

Air-sea coupling is critical in influencing atmospheric temperature and precipitation. The effect of greenhouse gases has influenced atmospheric variability and extreme events. Understanding and quantifying the effect of air-sea feedback on atmospheric variability and extremes remains unknown.

In this work we show results obtained from two numerical experiments. We use the HadSM4 configuration that couples the HadAM4 model at N144 resolution with a Slab Ocean to generate a large ensemble (~1000 members) of realizations of the 2013-14 October-March winter season, forced with a calibrated ocean heat convergence flux.

A twin experiment is performed by forcing HadAM4 with the diagnosed SST and sea ice from the ensemble, yielding a new ensemble with identical realizations of SST and sea ice. The only difference between the two ensembles is the enabling or disabling of the feedback of air-sea heat fluxes on SST.

While the impact of the feedback on the mean climate is relatively small, we show that its influence has important consequences for the variability of many important quantities, including air-sea fluxes and return periods of extreme events.

How to cite: Aengenheyster, M., Sparrow, S., Watson, P., Wallom, D., Zanna, L., and Allen, M.: Impact of sub-seasonal atmosphere-ocean interactions in a large ensemble, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12033,, 2022.

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