North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate

The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the southcentral Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the difference...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Rasmussen, Tine L., Thomsen, Erik, Moros, Matthias
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:https://pure.au.dk/portal/da/publications/north-atlantic-warming-during-dansgaardoeschger-events-synchronous-with-antarctic-warming-and-outofphase-with-greenland-climate(9a024687-c0f9-4e1f-a755-339eca379392).html
https://doi.org/10.1038/srep20535
Description
Summary:The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the southcentral Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that surface and intermediate-depth water south of Iceland warmed gradually synchronously with the Antarctic warming and out of phase with the abrupt warming of the Nordic seas and over Greenland. The hinge line between areas showing abrupt and gradual warming was close to the Greenland-Scotland Ridge and the marine system appears to be a 'push-and-pull' system rather than a seesaw system. 'Pull' during the warm interstadials, when convection in the Nordic seas was active; 'push' during the cold stadials, when convection stopped and warm water from the south-central Atlantic pushed northward gradually warming the North Atlantic and Nordic seas.