Atlantic Ocean circulation changes preceded millennial tropical South America rainfall events during the last glacial - Faculté des Sciences de Sorbonne Université Accéder directement au contenu
Article Dans Une Revue Geophysical Research Letters Année : 2015

Atlantic Ocean circulation changes preceded millennial tropical South America rainfall events during the last glacial

Résumé

During the last glacial period, Greenland's climate shifted between cold (stadial) and warm (interstadial) phases that were accompanied by ocean circulation changes characterized by reduced Atlantic Meridional Overturning Circulation (AMOC) during stadials. Here we present new data from the western tropical Atlantic demonstrating that AMOC slowdowns preceded some of the large South American rainfall events that took place during stadials. Based on 231 Pa/ 230 Th and Ti/Ca measurements in the same sediment core, we determine that the AMOC started to slowdown 1420 ± 250 and 690 ± 180 (1σ) years before the onset of two large precipitation events associated with Heinrich stadials. Our results bring unprecedented evidence that AMOC changes could be at the origin of the large precipitation events observed in tropical South America during Heinrich stadials. In addition, we propose a mechanism explaining the differences in the extent and timing of AMOC slowdowns associated with shorter and longer stadials.
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Dates et versions

hal-02884305 , version 1 (17-09-2020)

Identifiants

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Pierre Burckel, Claire Waelbroeck, Jeanne Gherardi, Sylvain Pichat, Helge W. Arz, et al.. Atlantic Ocean circulation changes preceded millennial tropical South America rainfall events during the last glacial. Geophysical Research Letters, 2015, 42 (2), pp.411-418. ⟨10.1002/2014GL062512⟩. ⟨hal-02884305⟩
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