Data/hora: 09/06/2024 12:37:21

Provedor de dados: | 5
País: | France
Título: | Dansgaard-Oeschger cycles: Interactions between ocean and sea ice intrinsic to the Nordic seas
Autores: | Dokken, Trond M.; Nisancioglu, Kerim H.; Li, Camille; Battisti, David S.; Kissel, Catherine.
Data: | 2013-09
Ano: | 2013
Palavras-chave: | D-O cycles; Nordic seas; Marine sediment core; Greenland ice core; Abrupt changes; Sea ice.
Resumo: | Dansgaard-Oeschger (D-O) cycles are the most dramatic, frequent, and wide-reaching abrupt climate changes in the geologic record. On Greenland, D-O cycles are characterized by an abrupt warming of 105 degrees C from a cold stadial to a warm interstadial phase, followed by gradual cooling before a rapid return to stadial conditions. The mechanisms responsible for these millennial cycles are not fully understood but are widely thought to involve abrupt changes in Atlantic Meridional Overturning Circulation due to freshwater perturbations. Here we present a new, high-resolution multiproxy marine sediment core monitoring changes in the warm Atlantic inflow to the Nordic seas as well as in local sea ice cover and influx of ice-rafted debris. In contrast to previous studies, the freshwater input is found to be coincident with warm interstadials on Greenland and has a Fennoscandian rather than Laurentide source. Furthermore, the data suggest a different thermohaline structure for the Nordic seas during cold stadials in which relatively warm Atlantic water circulates beneath a fresh surface layer and the presence of sea ice is inferred from benthic oxygen isotopes. This implies a delicate balance between the warm subsurface Atlantic water and fresh surface layer, with the possibility of abrupt changes in sea ice cover, and suggests a novel mechanism for the abrupt D-O events observed in Greenland ice cores.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00264/37490/35779.pdf

DOI:10.1002/palo.20042

https://archimer.ifremer.fr/doc/00264/37490/

Editor: | Amer Geophysical Union
Formato: | application/pdf
Fonte: | Paleoceanography (0883-8305) (Amer Geophysical Union), 2013-09 , Vol. 28 , N. 3 , P. 491-502

Fonte:

2013. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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