Data/hora: 02/06/2024 01:11:59

Provedor de dados: | 5
País: | France
Título: | Rbiative timing of precipitation and ocean circui In changes in the western equatorial Atlantic over the last 45 kyr
Autores: | Waelbroeck, Claire; Pichat, Sylvain; Bohm, Evelyn; Lougheed, Bryan C.; Faranda, Davide; Vrac, Mathieu; Missiaen, Lise; Vazquez Riveiros, Natalia; Burckel, Pierre; Lippold, Joerg; Arz, Helge W.; Dokken, Trond; Thil, Francois; Dapoigny, Arnaud.
Data: | 2018-09
Ano: | 2018
Resumo: | Thanks to its optimal location on the northern Brazilian margin, core MD09-3257 records both ocean circulation and atmospheric changes. The latter occur locally in the form of increased rainfall on the adjacent continent during the cold intervals recorded in Greenland ice and northern North Atlantic sediment cores (i.e., Greenland stadials). These rainfall events are recorded in MD09-3257 as peaks in ln(Ti / Ca). New sedimentary Pa / Th data indicate that mid-depth western equatorial water mass transport decreased during all of the Greenland stadials of the last 40 kyr. Using cross-wavelet transforms and spectrogram analysis, we assess the relative phase between the MD09-3257 sedimentary Pa / Th and ln(Ti/Ca) signals. We show that decreased water mass transport between a depth of similar to 1300 and 2300 m in the western equatorial Atlantic preceded increased rainfall over the adjacent continent by 120 to 400 yr at Dansgaard-Oeschger (D-O) frequencies, and by 280 to 980 yr at Heinrich-like frequencies. We suggest that the large lead of ocean circulation changes with respect to changes in tropical South American precipitation at Heinrich-like frequencies is related to the effect of a positive feedback involving iceberg discharges in the North Atlantic. In contrast, the absence of widespread ice rafted detrital layers in North Atlantic cores during D-O stadials supports the hypothesis that a feedback such as this was not triggered in the case of D-O stadials, with circulation slowdowns and subsequent changes remaining more limited during D-O stadials than Heinrich stadials.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00460/57126/59040.pdf

http://archimer.ifremer.fr/doc/00460/57126/59041.pdf

http://archimer.ifremer.fr/doc/00460/57126/59043.xlsx

http://archimer.ifremer.fr/doc/00460/57126/59044.pdf

http://archimer.ifremer.fr/doc/00460/57126/59045.pdf

http://archimer.ifremer.fr/doc/00460/57126/59046.xlsx

http://archimer.ifremer.fr/doc/00460/57126/59047.pdf

DOI:10.5194/cp-14-1315-2018

https://archimer.ifremer.fr/doc/00460/57126/

Editor: | Copernicus Gesellschaft Mbh
Relação: | info:eu-repo/grantAgreement/EC/FP7/339108/EU//ACCLIMATE
Formato: | application/pdf
Fonte: | Climate Of The Past (1814-9324) (Copernicus Gesellschaft Mbh), 2018-09 , Vol. 14 , N. 9 , P. 1315-1330

Fonte:

Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License.

info:eu-repo/semantics/openAccess

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