EGU21-15246
https://doi.org/10.5194/egusphere-egu21-15246
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Brewer-Dobson circulation in CMIP6

Natalia Calvo1, Marta Abalos1, Samuel Benito-Barca1, Hella Garny2, Steven Hardiman3, and Pu Lin4
Natalia Calvo et al.
  • 1Dpt. Earth Physics and Astrophysics, Universidad Complutense de Madrid, Madrid, Spain (nataliac@fis.ucm.es)
  • 2DLR, Germany
  • 3Metoffice , United Kingdom
  • 4GFDL, USA

The Brewer-Dobson circulation (BDC) is a key feature of the stratosphere that models need to accurately represent in order to improve the representation of surface climate variability. For the first time, the Climate Model Intercomparison Project includes in its phase 6 (CMIP6) a set of diagnostics that allow for careful evaluation of the BDC. Here, the BDC is evaluated against observations and reanalyses using historical simulations. CMIP6 results confirm the well-known inconsistency in BDC trends between observations and models in the middle and upper stratosphere. The increasing CO2 simulations feature a robust acceleration of the BDC but also reveal large uncertainties in the deep branch trends. The very close connection between the shallow branch and surface temperature is highlighted, which is absent in the deep branch. The trends in mean age of air are shown to be more robust throughout the stratosphere than those in the residual circulation.

How to cite: Calvo, N., Abalos, M., Benito-Barca, S., Garny, H., Hardiman, S., and Lin, P.: The Brewer-Dobson circulation in CMIP6, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15246, https://doi.org/10.5194/egusphere-egu21-15246, 2021.

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