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

Overturning Variations in the South Atlantic in an Ocean Reanalyses Ensemble

Jon Baker1, Richard Renshaw1, Laura Jackson1, Clotilde Dubois2, Doroteaciro Iovino3, Hao Zuo4, Renellys Perez5, Shenfu Dong5, and Marion Kersalé5
Jon Baker et al.
  • 1Met Office, United Kingdom of Great Britain – England, Scotland, Wales (
  • 2Mercator Océan, France
  • 3Centro Euro-Mediterraneo sui Cambiamenti Climatici, Italy
  • 4European Centre for Medium-Range Weather Forecasts, United Kingdom
  • 5NOAA Atlantic Oceanographic and Meteorological Laboratory, USA

The ocean's Atlantic Meridional Overturning Circulation (AMOC) has a significant influence on global climate through its meridional transport of heat and carbon. The Southern Ocean is the conduit connecting the South Atlantic Ocean to the Pacific and Indian Oceans. Thus, overturning in the South Atlantic plays a crucial role in determining the pathways of the global overturning circulation and the transports into and out of the Atlantic Ocean. Understanding the nature and causes of its multiannual to multidecadal variation in this region is critical to improve our understanding of the MOC and more accurately predict its future changes and impacts. We analyse the South Atlantic overturning at 34.5°S in an ensemble of eddy permitting ¼ degree global ocean reanalyses, constrained by observations and historical forcings, over the period 1993-2021. This overturning transport and the meridional heat transport are validated against the continuous measurements obtained along the South Atlantic Meridional Overturning Circulation – Basin-wide Array (SAMBA). The ability of each reanalysis to capture the observed changes in the overturning will be determined, providing confidence in their ability to simulate changes prior to the availability of SAMBA, and exposing their limitations. We analyse the vertical variation of the transports and their temporal variability on various timescales. This research complements previous studies investigating changes in the subtropical and subpolar North Atlantic overturning using the same reanalyses ensemble, which was shown to provide a good representation of observations.

How to cite: Baker, J., Renshaw, R., Jackson, L., Dubois, C., Iovino, D., Zuo, H., Perez, R., Dong, S., and Kersalé, M.: Overturning Variations in the South Atlantic in an Ocean Reanalyses Ensemble, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5416,, 2022.

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