Climatic and insolation control on the high-resolution total air content in the NGRIP ice core

Eicher, O.; Baumgartner, M.; Schilt, A.; Schmitt, J.; Schwander, J.; Stocker, T. F.; Fischer, H. (2016). Climatic and insolation control on the high-resolution total air content in the NGRIP ice core. Climate of the past, 12(6), pp. 1979-1993. Copernicus Publications 10.5194/cpd-11-5509-2015

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Because the total air content (TAC) of polar ice is directly affected by the atmospheric pressure, its record in polar ice cores was considered as a proxy for past ice sheet elevation changes. However the Antarctic ice core TAC record is known to also contain an insolation signature, although the underlying physical mechanisms are still a matter of debate. Here we present a high-resolution TAC record over the whole North Greenland Ice Core Project ice core, covering the last 120 000 years, which independently supports an insolation signature in Greenland. Wavelet analysis reveals a clear precession and obliquity signal similar to previous findings on Antarctic TAC, with different insolation history. In our high-resolution record we also find a decrease of 3–5% (3–4.2mLkg⁻¹) in TAC as a response to Dansgaard-Oeschger-Events (DO-events). TAC starts to decrease in parallel to increasing Greenland surface temperature and slightly before CH₄ reacts to the warming, but also shows a two-step decline that lasts for several centuries into the warm phase/interstadial. The TAC response is larger than expected considering only local temperature and atmospheric pressure as a driver, pointing to transient firnification response caused by the accumulation-induced increase in the load on the firn at bubble close-off, while temperature changes deeper in the firn are still small.

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)

UniBE Contributor:

Eicher, Olivier; Baumgartner, Matthias; Schilt, Adrian; Schmitt, Jochen; Schwander, Jakob; Stocker, Thomas and Fischer, Hubertus

Subjects:

500 Science > 530 Physics

ISSN:

1814-9324

Publisher:

Copernicus Publications

Language:

English

Submitter:

Doris Rätz

Date Deposited:

14 Nov 2016 16:50

Last Modified:

14 Nov 2016 16:50

Publisher DOI:

10.5194/cpd-11-5509-2015

BORIS DOI:

10.7892/boris.89328

URI:

https://boris.unibe.ch/id/eprint/89328

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