Quantitative estimate of the paleo-Agulhas leakage

Thibaut Caley, Frank J.C. Peeters, Arne Biastoch, Linda Rossignol, Erik Van Sebille, Jonathan Durgadoo, Bruno Malaizé, Jacques Giraudeau, Kristina Arthur, Rainer Zahn

Research output: Contribution to journalArticleResearchpeer-review

18 Citations (Scopus)

Abstract

The Indian-Atlantic water exchange south of Africa (Agulhas leakage) is a key component of the global ocean circulation. No quantitative estimation of the paleo-Agulhas leakage exists. We quantify the variability in interocean exchange over the past 640,000 years, using planktic foraminiferal assemblage data from two marine sediment records to define an Agulhas leakage efficiency index. We confirm the validity of our new approach with a numerical ocean model that realistically simulates the modern Agulhas leakage changes. Our results suggest that, during the past several glacial-interglacial cycles, the Agulhas leakage varied by ~10 sverdrup and more during major climatic transitions. This lends strong credence to the hypothesis that modifications in the leakage played a key role in changing the overturning circulation to full strength mode. Our results are instrumental for validating and quantifying the contribution of the Indian-Atlantic water leakage to the global climate changes. Key Points A quantitative index for the Agulhas leakage has been developed Paleo-Agulhas leakage over the past 640,000 years has been quantified We provide reference points for further analyses and interpretations ©2014. American Geophysical Union. All Rights Reserved.
Original languageEnglish
Pages (from-to)1238-1246
JournalGeophysical Research Letters
Volume41
Issue number4
DOIs
Publication statusPublished - 28 Feb 2014

Keywords

  • numerical ocean model
  • overturning circulation
  • planktic foraminiferal
  • quantitative palaeo Agulhas leakage

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