Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation
Type | Article | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Date | 2021-01 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Nuber Sophie1, Rae James2, Andersen Morten3, Zhang Xu4, de Boer Bas5, Dumont Matthew2, Sun Yuchen, Mithan Huw1, Hall Ian6, Barker Stephen7 | ||||||||||||
Affiliation(s) | 1 : National Taiwan University, Taiwan 2 : University of St Andrews, UK 3 : School of Earth and Ocean Sciences, Cardiff University, Uk 4 : State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China 5 : Vrije Universiteit Amsterdam, Netherlands 6 : School of Earth and Ocean Sciences Sciences 7 : Cardiff University, UK |
||||||||||||
Source | Research Square (Research Square Platform LLC), 2021-01 , N. Version 1 , P. 12p. | ||||||||||||
DOI | 10.21203/rs.3.rs-1038170/v1 | ||||||||||||
Note | This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice. | ||||||||||||
Keyword(s) | Agulhas leakage salinity, Atlantic overturning circulation, Indian Ocean | ||||||||||||
Abstract | The Indian Ocean has been proposed as an important source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean’s overturning circulation. However, while past changes in Agulhas leakage volume have been explored, little is known about this water’s salt content, representing a major gap in our understanding of Agulhas salinity supply. Here, we present new planktonic foraminiferal Mg/Ca-derived sea surface temperatures (SST) and stable isotope-derived salinity reconstructions for the last 1.2Ma from the western Indian Ocean source waters of the Agulhas Leakage to investigate glacial-interglacial changes in surface water properties. We find that SST and relative salinity both increase during glaciation, leading to high salinity and SST during glacial maxima. We show that the onset of surface salinification and warming in the Indian Ocean occurs during a phase of rapid land-bridge exposure in the Indonesian archipelago induced by sea level lowering. We link these findings to new global climate model results which show that the export of salt from the Indian Ocean via the Agulhas Leakage can directly impact the deglacial Atlantic meridional overturning circulation and therefore global climate. |
||||||||||||
Full Text |
|