CO2 and O2/N2 variations in and just below the bubble–clathrate transformation zone of Antarctic ice cores

Lüthi, Dieter; Bereiter, Bernhard; Stauffer, Bernhard; Winkler, Renato; Schwander, Jakob; Kindler, Philippe; Leuenberger, Markus; Kipfstuhl, Sepp; Capron, Emilie; Landais, Amaelle; Fischer, Hubertus; Stocker, Thomas F. (2010). CO2 and O2/N2 variations in and just below the bubble–clathrate transformation zone of Antarctic ice cores. Earth and planetary science letters, 297(1-2), pp. 226-233. Amsterdam: Elsevier 10.1016/j.epsl.2010.06.023

[img] Text
1-s2.0-S0012821X10003985-main.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

CO2 measurements on the EPICA (European Project for Ice Coring in Antarctica) DML ice core in depth levels just below the bubble ice–clathrate ice transformation zone (1230–2240 m depth) were performed. In the youngest part (1230–1600 m), they reveal variations of up to 25 ppmv around the mean atmospheric concentration within centimetres, corresponding to a snow deposition interval of a few years. Similar results are found at corresponding depth regions of the Dome C and the Talos Dome ice cores. Since we can exclude all hitherto known processes altering the concentration of CO2 in ice cores, we present a hypothesis about spatial fractionation of air components related to episodically increasing clathrate formation followed by diffusion processes from bubbles to clathrates. This hypothesis is supported by optical line-scan observations and by O2/N2 measurements at the same depth where strong CO2 variations are detected. Below the clathrate formation zone, this small-scale fractionation process is slowly smoothed out, most likely by diffusion, regaining the initial mean atmospheric concentration. Although this process compromises the representativeness of a single CO2 measurement on small ice samples in the clathrate formation zone of an ice core, it does not affect the mean atmospheric CO2 concentration if CO2 values are averaged over a sufficiently long depth scale (> 10 cm in case of the EPICA DML ice core).

Item Type:

Journal Article (Original Article)


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:

Bereiter, Bernhard, Stauffer, Bernhard, Schwander, Jakob, Kindler, Philippe, Leuenberger, Markus, Fischer, Hubertus, Stocker, Thomas


500 Science > 530 Physics








Factscience Import

Date Deposited:

04 Oct 2013 14:16

Last Modified:

02 Mar 2023 23:20

Publisher DOI:


Web of Science ID:




URI: (FactScience: 209089)

Actions (login required)

Edit item Edit item
Provide Feedback