EPICA Dronning Maud Land Ice Core 64-30KYr CO2 Data Lüthi, D.; Bereiter, B.; Stauffer, B.; Winkler, R.; Schwander, J.; Kindler, P.; Leuenberger, M.; Kipfstuhl, S.; Capron, E.; Landais, A.; Fischer, H.; Stocker, T.F. Lüthi, D. Bereiter, B. Stauffer, B. Winkler, R. Schwander, J. Kindler, P. Leuenberger, M. Kipfstuhl, S. Capron, E. Landais, A. Fischer, H. Stocker, T.F. carbon cycle earth science/paleoclimate/climate forcing|ice cores (carbon dioxide,bulk atmosphere,one standard deviation,parts per million,null,climate forcing|ice cores,null,null,N,null) earth science/paleoclimate/climate forcing|ice cores (carbon dioxide,bulk atmosphere,null,parts per million,null,climate forcing|ice cores,null,null,N,null) earth science/paleoclimate/ice cores (depth,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (gas age,null,null,calendar year before present,null,ice cores,null,null,N,null) earth science/paleoclimate/ice core (EPICA Dronning Maud Land>LATITUDE -75>LONGITUDE .07) 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). STUDY NOTES: CO2 record from the EPICA Dronning Maud Land ice core covering the time period between 64000 and 30000 yr BP. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Lüthi, D. Investigator : Bereiter, B. Investigator : Stauffer, B. Investigator : Winkler, R. Investigator : Schwander, J. Investigator : Kindler, P. Investigator : Leuenberger, M. Investigator : Kipfstuhl, S. Investigator : Capron, E. Investigator : Landais, A. Investigator : Fischer, H. Investigator : Stocker, T.F. 2010-10-04 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/9898 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.xls https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.xls English https://www.ncdc.noaa.gov/paleo/study/9898 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml-co2-64-30ka.xls Lüthi, D., B. Bereiter, B. Stauffer, R. Winkler, J. Schwander, P. Kindler, M. Leuenberger, S. Kipfstuhl, E. Capron, A. Landais, H. Fischer, and T.F. Stocker. 2010. CO2 and O2/N2 variations in and just below the bubble-clathrate transformation zone of Antarctic ice cores. Earth and Planetary Science Letters, Vol. 297, pp. 226-233. doi:10.1016/j.epsl.2010.06.023 START YEAR: 63750 cal yr BP * END YEAR: 30775 cal yr BP .07 -75 .07 -75