Decadal-scale progression of the onset of Dansgaard–Oeschger warming events

Erhardt, Tobias; Capron, Emilie; Rasmussen, Sune Olander; Schüpbach, Simon; Bigler, Matthias; Adolphi, Florian; Fischer, Hubertus (2019). Decadal-scale progression of the onset of Dansgaard–Oeschger warming events. Climate of the past, 15(2), pp. 811-825. Copernicus Publications 10.5194/cp-15-811-2019

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During the last glacial period, proxy records throughout the Northern Hemisphere document a succession of rapid millennial-scale warming events, called Dansgaard–Oeschger (DO) events. A range of different mechanisms has been proposed that can produce similar warming in model experiments; however, the progression and ultimate trigger of the events are still unknown. Because of their fast nature, the progression is challenging to reconstruct from paleoclimate data due to the limited temporal resolution achievable in many archives and cross-dating uncertainties between records. Here, we use new high-resolution multi-proxy records of sea-salt (derived from sea spray and sea ice over the North Atlantic) and terrestrial (derived from the central Asian deserts) aerosol concentrations over the period 10–60 ka from the North Greenland Ice Core Project (NGRIP) and North Greenland Eemian Ice Drilling (NEEM) ice cores in conjunction with local precipitation and temperature proxies from the NGRIP ice core to investigate the progression of environmental changes at the onset of the warming events at annual to multi-annual resolution. Our results show on average a small lead of the changes in both local precipitation and terrestrial dust aerosol concentrations over the change in sea-salt aerosol concentrations and local temperature of approximately one decade. This suggests that, connected to the reinvigoration of the Atlantic meridional overturning circulation and the warming in the North Atlantic, both synoptic and hemispheric atmospheric circulation changes at the onset of the DO warming, affecting both the moisture transport to Greenland and the Asian monsoon systems. Taken at face value, this suggests that a collapse of the sea-ice cover may not have been the initial trigger for the DO warming.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Physics Institute

UniBE Contributor:

Erhardt, Tobias and Fischer, Hubertus

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

1814-9324

Publisher:

Copernicus Publications

Funders:

[4] Swiss National Science Foundation
[31] Oeschger Centre for Climate Change Research (OCCR)
[UNSPECIFIED] EU 7th framework program
[UNSPECIFIED] Carlsberg Foundation
[20] Swedish Research Council

Language:

English

Submitter:

Hubertus Fischer

Date Deposited:

02 Jul 2019 09:21

Last Modified:

02 Jul 2019 09:21

Publisher DOI:

10.5194/cp-15-811-2019

Uncontrolled Keywords:

ice core Greenland aerosol paleoclimate

BORIS DOI:

10.7892/boris.130378

URI:

https://boris.unibe.ch/id/eprint/130378

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