NGRIP CH 4 concentration from 120 to 10 kyr before present and its relation to a δ 15 N temperature reconstruction from the same ice core ...

• Main Authors: Chappellaz, J., Schilt, Adrian, Floch, G., Leuenberger, Markus, Baumgartner, Matthias, Fischer, Hubertus, Kindler, Philippe, Capron, E., Spahni, Renato, Stocker, Thomas, Schwander, Jakob, Eicher, Olivier
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2014
• Subjects: 530 Physics; Greenland; Greenland ice core; Greenland Ice core Project; ice core; NGRIP; North Greenland; North Greenland Ice Core Project
• Online Access: https://dx.doi.org/10.7892/boris.53692; http://boris.unibe.ch/53692/

During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard–Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from the Preboreal Holocene (PB) back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the local Greenland NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core (Kindler et al., 2014). We find the ratio to oscillate between 5 parts per billion (ppb) per °C and 18 ppb °C−1 with the approximate frequency of the precessional cycle. A remarkably high ratio of 25.5 ppb °C−1 is reached ...