noaa-icecore-14651 Antarctic Ice Cores 160KYr Methane Isotope Data Möller, L.; Sowers, T.; Bock, M.; Spahni, R.; Behrens, M.; Schmitt, J.; Miller, H.; Fischer, H. Antarctic Ice Cores 160KYr Methane Isotope Data 2013-06-17 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/14651 Investigator L. Möller Investigator T. Sowers Investigator M. Bock Investigator R. Spahni Investigator M. Behrens Investigator J. Schmitt Investigator H. Miller Investigator H. Fischer earth science paleoclimate ice cores notes,null,null,null,null,ice cores,null,null,C,null earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,corrected,null,N,corrected for krypton earth science paleoclimate ice cores delta 13C,methane,one standard deviation,per mil VPDB,null,ice cores,null,null,N,null earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,corrected,null,N,corrected for machine specific drift earth science paleoclimate ice cores ice age,null,null,calendar year before present,null,ice cores,null,null,N,Antarctic unified age scale earth science paleoclimate ice cores delta 2H,methane,one standard deviation,per mil,null,ice cores,null,null,N,standard deviation of the standard air measurements used to calibrate dD to the VSMOW scale earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,corrected,null,N,corrected for glacial offset due to gravitational settling earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,corrected,null,N,corrected for gravitational settling earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,null,null,N,deviations due to krypton interference earth science paleoclimate ice cores delta 2H,methane,null,per mil VSMOW,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,Antarctic unified age scale 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,Antarctic unified age scale; EDC3 corrected earth science paleoclimate ice cores delta 13C,methane,null,per mil VPDB,null,ice cores,corrected,null,N,corrected for interlaboratory offset earth science paleoclimate ice cores gas age,null,null,calendar year before present,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,methane synchronization earth science paleoclimate ice core carbon isotopes earth science paleoclimate ice core hydrogen isotopes geoscientificInformation carbon cycle 164013 cal yr BP 9937 cal yr BP Complete -78.47 -75 .07 106.8 2892 2892 Continent Antarctica Vostok>LATITUDE -78.47>LONGITUDE 106.8 Continent Antarctica EPICA Dronning Maud Land>LATITUDE -75>LONGITUDE .07 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

325 Broadway, E/NE31

Boulder CO 80305-3328 USA online ASCII Lars Möller, Todd Sowers, Michael Bock, Renato Spahni, Melanie Behrens, Jochen Schmitt, Heinrich Miller, and Hubertus Fischer 2013 Nature Geoscience 6 885-890 10.1038/ngeo1922 https://www.nature.com/articles/ngeo1922

During the last glacial cycle, greenhouse gas concentrations fluctuated on decadal and longer timescales. Concentrations of methane, as measured in polar ice cores, show a close connection with Northern Hemisphere temperature variability, but the contribution of the various methane sources and sinks to changes in concentration is still a matter of debate. Here we assess changes in methane cycling over the past 160,000 years by measurements of the carbon isotopic composition d13C of methane in Antarctic ice cores from Dronning Maud Land and Vostok. We find that variations in the d13C of methane are not generally correlated with changes in atmospheric methane concentration, but instead more closely correlated to atmospheric CO2 concentrations. We interpret this to reflect a climatic and CO2-related control on the isotopic signature of methane source material, such as ecosystem shifts in the seasonally inundated tropical wetlands that produce methane. In contrast, relatively stable d13C values occurred during intervals of large changes in the atmospheric loading of methane. We suggest that most methane sources - most notably tropical wetlands - must have responded simultaneously to climate changes across these periods. STUDY NOTES: We reconstructed atmospheric d13CH4 records using wet extraction techniques and continuous flow gas chromatography combustion isotope ratio mass spectrometry (GC/C/IRMS) measurements performed on ice core material from both the European Project for Ice Coring in Antarctica (EPICA) core from Dronning Maud Land (EDML) and the Vostok cores. At the Alfred Wegener Institute (AWI) we analyzed 151 samples from the EDML core (including 32 replicates, reproducibility of 0.2 , 1s) to construct a high resolution record between 20 kyr and 75 kyr BP (1.000 years before present, present referring to 1950 AD) with an average temporal resolution of better than one sample every 500 years. The period covering the two most pronounced climatic excursions in the Greenland temperature record during MIS 3 (DO events 7 and 8) were sampled with a resolution of ~200 years. A complementary record of 79 samples of Vostok ice core material was measured at the Pennsylvania State University (PSU) covering a time period from 50 kyr to 160 kyr BP with an analytical uncertainty of 0.3 (1s), equivalent to an average temporal resolution of 1660 years. The two records were corrected for an instrumental interference from atmospheric krypton, for gravitational settling in the firn, and a minor inter-laboratory offset of 0.14 . All d13C values are reported versus Vienna PeeDee Belemnite (VPDB). We further analyzed 20 samples of EDML ice for dD(CH4) with an external precision of about 2.5 (1s). The measurements were performed at the University of Bern using a purge and trap extraction coupled to a gas chromatography pyrolysis isotope ratio mass spectrometer (GC/P/IRMS) and cover the MIS 5/4 transition with an average resolution of 1.5 kyr in between 54 and 85 kyr BP. The dD(CH4) values are reported with respect to the international Vienna Standard Mean Ocean Water (VSMOW) scale.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml2013ddch4.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2013d13ch4.txt GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/maud/edml2013d13ch4.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11