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

• Main Authors: Schilt, A., Baumgartner, M., Eicher, O., Fischer, H., Schwander, J., Stocker, T. F., Schmitt, J.
• Format: Text
• Language: English
• Published: Copernicus Publications 2016
• Subjects: 530 Physics; Antarctic; The Antarctic; Greenland; Tac; Antarc*; Dansgaard-Oeschger events; Greenland ice core; Greenland Ice core Project; ice core; Ice Sheet; NGRIP; North Greenland; North Greenland Ice Core Project
• Online Access: https://dx.doi.org/10.7892/boris.89328; http://boris.unibe.ch/89328/

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 ...