Changes in the atmospheric CH4 gradient between Greenland and Antarctica during the Holocene ...

• Main Authors: Chappellaz, Jérôme, Blunier, Thomas, Kints, Sophie, Dällenbach, André, Barnola, Jean-Marc, Schwander, Jakob, Raynaud, Dominique, Stauffer, Bernhard
• Format: Article in Journal/Newspaper
• Language: English
• Published: University of Bern 1997
• Subjects: Antarctic; Byrd; Greenland; Antarc*; Greenland ice core; Greenland Ice core Project; ice core
• Online Access: https://dx.doi.org/10.48350/158723; https://boris-portal.unibe.ch/handle/20.500.12422/43337

High-resolution records of atmospheric methane over the last 11,500 years have been obtained from two Antarctic ice cores (D47 and Byrd) and a Greenland core (Greenland Ice Core Project). These cores show similar trapping conditions for trace gases in the ice combined with a comparable sampling resolution; this together with a good relative chronology, provided by unequivocal CH4 features, allows a direct comparison of the synchronized Greenland and Antarctic records, and it reveals significant changes in the interpolar difference of CH4 mixing ratio with time. On the average, over the full Holocene records, we find an interpolar difference of 44±7 ppbv. A minimum difference of 33±7 ppbv is observed from 7 to 5 kyr B.P. whereas the maximum gradient (50±3 ppbv) took place from 5 to 2.5 kyr B.P. A gradient of 44±4 ppbv is observed during the early Holocene (11.5 to 9.5 kyr B.P). We use a three-box model to translate the measured differences into quantitative contributions of methane sources in the tropics and ...