Data/hora: 03/06/2024 01:05:33

Provedor de dados: | 5
País: | France
Título: | Glacial reduction and millennial-scale variations in Drake Passage throughflow
Autores: | Lamy, Frank; Arz, Helge W.; Kilianc, Rolf; Lange, Carina B.; Lembke-jene, Lester; Wengler, Marc; Kaiser, Jerome; Baeza-urrea, Oscar; Hall, Ian R.; Harada, Naomi; Tiedemann, Ralf.
Data: | 2015-11
Ano: | 2015
Palavras-chave: | Paleoceanography; Drake Passage; Antarctic Circumpolar Current; Glacial-interglacial changes; Sedimentology.
Resumo: | The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean's role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total reduction of DP transport and reveal an up to similar to 40% decrease in flow speed along the northernmost ACC pathway entering the DP during glacial times. Superimposed on this long-term decrease are high-amplitude, millennial-scale variations, which parallel Southern Ocean and Antarctic temperature patterns. The glacial intervals of strong weakening of the ACC entering the DP imply an enhanced export of northern ACC surface and intermediate waters into the South Pacific Gyre and reduced Pacific-Atlantic exchange through the DP ("cold water route"). We conclude that changes in DP throughflow play a critical role for the global meridional overturning circulation and interbasin exchange in the Southern Ocean, most likely regulated by variations in the westerly wind field and changes in Antarctic sea ice extent.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00351/46233/46119.pdf

DOI:10.1073/pnas.1509203112

https://archimer.ifremer.fr/doc/00351/46233/

Editor: | Natl Acad Sciences
Formato: | application/pdf
Fonte: | Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2015-11 , Vol. 112 , N. 44 , P. 13496-13501

Fonte:

2015 National Academy of Sciences.

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