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On the role of the Agulhas system in ocean circulation and climate

Nature volume 472, pages 429–436 (2011)Cite this article

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Abstract

The Atlantic Ocean receives warm, saline water from the Indo-Pacific Ocean through Agulhas leakage around the southern tip of Africa. Recent findings suggest that Agulhas leakage is a crucial component of the climate system and that ongoing increases in leakage under anthropogenic warming could strengthen the Atlantic overturning circulation at a time when warming and accelerated meltwater input in the North Atlantic is predicted to weaken it. Yet in comparison with processes in the North Atlantic, the overall Agulhas system is largely overlooked as a potential climate trigger or feedback mechanism. Detailed modelling experiments—backed by palaeoceanographic and sustained modern observations—are required to establish firmly the role of the Agulhas system in a warming climate.

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Figure 1: Agulhas leakage affected by westerly winds and position of subtropical front.
Figure 2: Warm, saline Agulhas waters influence temperature and salinity in the Atlantic over the full depth of the water column.
Figure 3: Agulhas leakage advects warm, saline waters into the Atlantic, predominantly through Agulhas rings.
Figure 4: Palaeoceanographic time series from the Agulhas leakage corridor spanning the last 570,000 yr.

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Acknowledgements

Fig. 1 was produced by E. Van Sebille and Fig. 2 was produced by H. Van Aken. We thank D. leBars for discussions. L.M.B. is funded by the US National Science Foundation through the ACT project, award no. OCE-0850891. W.P.M.D.R. is funded by the Netherlands Organization for Scientific Research through the INATEX program, ZKO no. 839.08.430. R.Z. receives funding from the Ministerio de Ciencia e Innovación, Spain, through grant CGL2007-61579/CLI. A.B. and R.Z. acknowledge funding by the EC FP7 Marie Curie ITN GATEWAYS. This document is based on work partially supported by the US National Science Foundation under Grant OCE-0938349 to the Scientific Committee on Oceanic Research.

Author information

Authors and Affiliations

  1. Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, 33149, Florida, USA

    Lisa M. Beal

  2. Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands

    Wilhelmus P. M. De Ruijter

  3. Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany

    Arne Biastoch

  4. Institució Catalana de Recerca i Estudis Avançats (ICREA), Institut de Ciència i Tecnologia Ambientals (ICTA), Departament de Física, Universitat Autònoma de Barcelona, Bellaterra E-08193, Spain

    Rainer Zahn

  5. NOAA Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, 98115, Washington, USA

    Meghan Cronin

  6. South African Environmental Observation Network, Private Bag X2, Roggebaai 8012, South Africa

    Juliet Hermes

  7. Department of Oceanography, University of Cape Town, 7700 Rondebosch, South Africa

    Johann Lutjeharms

  8. National Oceanography Centre, Southampton, European Way, Southampton SO14 3ZH, UK

    Graham Quartly & Paolo Cipollini

  9. Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

    Tomoki Tozuka

  10. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, 02139, Massachusetts, USA

    Sheekela Baker-Yeboah

  11. South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa

    Thomas Bornman

  12. Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands

    Henk Dijkstra

  13. School of Earth and Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3AT, UK

    Ian Hall

  14. Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany

    Wonsun Park

  15. Faculty of Earth and Life Sciences, Section Marine Biogeology, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands

    Frank Peeters

  16. Department of Oceanography, Laboratoire de Physique des Oceans (UMR 6523 CNRS, IFREMER, IRD, UBO), LMI ICEMASA, University of Cape Town, Cape Town, 7700 Rondebosch, South Africa

    Pierrick Penven

  17. NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, The Netherlands

    Herman Ridderinkhof & Jens Zinke

Authors
  1. Lisa M. Beal
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  2. Wilhelmus P. M. De Ruijter
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  3. Arne Biastoch
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  4. Rainer Zahn
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Consortia

SCOR/WCRP/IAPSO Working Group 136

  • Meghan Cronin
  • , Juliet Hermes
  • , Johann Lutjeharms
  • , Graham Quartly
  • , Tomoki Tozuka
  • , Sheekela Baker-Yeboah
  • , Thomas Bornman
  • , Paolo Cipollini
  • , Henk Dijkstra
  • , Ian Hall
  • , Wonsun Park
  • , Frank Peeters
  • , Pierrick Penven
  • , Herman Ridderinkhof
  •  & Jens Zinke

Contributions

The ideas presented here were developed jointly by L.M.B., W.P.M.D.R., A.B., R.Z. and the SCOR/WCRP/IAPSO Working Group 136 on the Climatic Importance of the Greater Agulhas System. Working Group 136 is sponsored by the Scientific Committee for Oceanic Research (SCOR), the World Climate Research Program (WCRP) and the International Association for the Physical Sciences of the Ocean (IAPSO).

Corresponding author

Correspondence to Lisa M. Beal.

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Competing interests

The authors declare no competing financial interests.

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Beal, L., De Ruijter, W., Biastoch, A. et al. On the role of the Agulhas system in ocean circulation and climate. Nature 472, 429–436 (2011). https://doi.org/10.1038/nature09983

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