noaa-icecore-23210 Vostok, Antarctica Ice Core 4G-2 61-58KYr Methane and d15N Data Fourteau, K.; Faïn, X.; Martinerie, P.; Landais, A.; Ekaykin, A.A.; Lipenkov, V.; Chappellaz, J.A. Vostok, Antarctica Ice Core 4G-2 61-58KYr Methane and d15N Data 2017-12-07 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/23210 Investigator K. Fourteau Investigator X. Faïn Investigator P. Martinerie Investigator A. Landais Investigator A.A. Ekaykin Investigator V. Lipenkov Investigator J.A. Chappellaz earth science paleoclimate ice cores depth,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate ice cores methane,bulk atmosphere,null,parts per billion,null,ice cores,corrected,continuous flow analysis|optical feedback cavity enhanced absorption spectroscopy,N,corrected for contamination and calibrated earth science paleoclimate ice cores methane,bulk atmosphere,null,parts per billion,null,ice cores,corrected,continuous flow analysis|optical feedback cavity enhanced absorption spectroscopy,N,values corresponding to layering artifacts removed earth science paleoclimate ice cores delta 15N,bulk atmosphere,null,per mil AIR,null,ice cores,null,null,N,values measured by mass spectrometry in extracted air after water and CO2 trap and corrected for O2/N2 chemical slope 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 nitrogen isotopes earth science paleoclimate ice core age control earth science paleoclimate ice core atmospheric gas geoscientificInformation 60829 cal yr BP 57907 cal yr BP Complete -78.47 -78.47 106.8 106.8 Continent Antarctica Vostok>LATITUDE -78.47>LONGITUDE 106.8 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

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Boulder CO 80305-3328 USA online ASCII Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz 2017 Climate of the Past 13 12 1815-1830 10.5194/cp-13-1815-2017 https://www.clim-past.net/13/1815/2017/

We investigate for the first time the loss and alteration of past atmospheric information from air trapping mechanisms under low-accumulation conditions through continuous CH4 (and CO) measurements. Methane concentration changes were measured over the Dansgaard-Oeschger event 17 (DO-17, - 60 000 yr BP) in the Antarctic Vostok 4G-2 ice core. Measurements were performed using continuous-flow analysis combined with laser spectroscopy. The results highlight many anomalous layers at the centimeter scale that are unevenly distributed along the ice core. The anomalous methane mixing ratios differ from those in the immediate surrounding layers by up to 50 ppbv. This phenomenon can be theoretically reproduced by a simple layered trapping model, creating very localized gas age scale inversions. We propose a method for cleaning the record of anomalous values that aims at minimizing the bias in the overall signal. Once the layered-trapping-induced anomalies are removed from the record, DO-17 appears to be smoother than its equivalent record from the high-accumulation WAIS Divide ice core. This is expected due to the slower sinking and densification speeds of firn layers at lower accumulation. However, the degree of smoothing appears surprisingly similar between modern and DO-17 conditions at Vostok. This suggests that glacial records of trace gases from low-accumulation sites in the East Antarctic plateau can provide a better time resolution of past atmospheric composition changes than previously expected. We also developed a numerical method to extract the gas age distributions in ice layers after the removal of the anomalous layers based on comparison with a weakly smoothed record. It is particularly adapted for the conditions of the East Antarctic plateau, as it helps to characterize smoothing for a large range of very low-temperature and low-accumulation conditions. STUDY NOTES: Vostok, Antarctica 61-58 kY 4G-2 ice core methane mixing ratio.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017ch4.txt NOAA Template File; Vostok 4G-2 61-58KYr Methane Mixing Ratio GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017d15n.txt NOAA Template File; Vostok 4G-2 61-58KYr d15N GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017age.txt NOAA Template File; Vostok 4G-2 61-58KYr Depth/Gas Age USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11