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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Tracking Spread of the Agulhas Leakage Into the Western South Atlantic and Its Northward Transmission During the Last Interglacial

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Author(s):
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Ballalai, Joao M. [1] ; Santos, Thiago P. [1] ; Lessa, Douglas O. [1] ; Venancio, Igor M. [2] ; Chiessi, Cristiano M. [3] ; Johnstone, Heather J. H. [4] ; Kuhnert, Henning [4] ; Claudio, Marcela R. [1] ; Toledo, Felipe [5] ; Costa, Karen B. [5] ; Albuquerque, Ana Luiza S. [1]
Total Authors: 11
Affiliation:
[1] Univ Fed Fluminense, Programa Geociencias Geoquim, Niteroi, RJ - Brazil
[2] Natl Inst Space Res INPE, Ctr Weather Forecasting & Climate Studies CPTEC, Cachoeira Paulista - Brazil
[3] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Sao Paulo, SP - Brazil
[4] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany
[5] Univ Sao Paulo, Inst Oceanog, Lab Paleoceanog Atlantico Sul, Sao Paulo, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY; v. 34, n. 11 NOV 2019.
Web of Science Citations: 1
Abstract

Intensification of the Agulhas Leakage (AL) during glacial terminations has long been proposed as a necessary mechanism for reverting the Atlantic Meridional Overturning Circulation (AMOC) to its interglacial mode. However, lack of records showing the downstream evolution of AL signal and substantial temporal differences between AL intensification and resumption of deep-water convection have cast doubt on the importance of this mechanism to the AMOC. Here, we analyze a combination of new and previously published data relating to Mg/Ca-derived temperatures and ice volume-corrected seawater delta O-18 records (delta O-18(IVC-SW), as a proxy for relative changes in ocean salinity), which demonstrate propagation of AL signal via surface and thermocline waters to the western South Atlantic (Santos Basin) during Termination II and the early Last Interglacial. The saline AL waters were temporally stored in the upper subtropical South Atlantic until they were abruptly released in two stages into the North Atlantic via surface and thermocline waters at ca. 129 and 123 ka BP, respectively. Accounting for age model uncertainties, these two stages are coeval with the resumption of convection in the Labrador and Nordic seas during the Last Interglacial. We propose a mechanism whereby both active AL and a favorable ocean-atmosphere configuration in the tropical Atlantic were required to allow flux of AL waters into the North Atlantic, where they then contributed to enhancing the AMOC during the Last Interglacial period. Our results provide a framework that connects AL strengthening to the AMOC intensifications that followed glaciations. (AU)

FAPESP's process: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM)
Grantee:Cristiano Mazur Chiessi
Support Opportunities: Research Grants - Research Program on Global Climate Change - Young Investigators - Phase 2