{"NOAAStudyId":"23210","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","constraints":"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.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2017-12-07","dataPublisher":"NOAA","dataType":"ICE CORES","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/ice-core","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-icecore-23210.xml","doi":null,"earliestYearBP":60829,"earliestYearCE":-58879,"entryId":"noaa-icecore-23210","funding":[],"investigators":"Fourteau, K.; Faïn, X.; Martinerie, P.; Landais, A.; Ekaykin, A.A.; Lipenkov, V.; Chappellaz, J.A.","mostRecentYearBP":57907,"mostRecentYearCE":-55957,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/23210","originalSource":null,"publication":[{"abstract":"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.","author":{"name":"Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz"},"citation":"Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz. 2017. Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low-accumulation conditions. Climate of the Past, 13(12), 1815-1830. doi: 10.5194/cp-13-1815-2017","edition":null,"identifier":{"id":"10.5194/cp-13-1815-2017","type":"doi","url":"http://dx.doi.org/10.5194/cp-13-1815-2017"},"issue":"12","journal":"Climate of the Past","pages":"1815-1830","pubRank":"1","pubYear":2017,"reportNumber":null,"title":"Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low-accumulation conditions","type":"publication","volume":"13"}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"19976","geo":{"geoType":"Feature","geometry":{"coordinates":["-78.47","106.8"],"type":"POINT"},"properties":{"easternmostLongitude":"106.8","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"-78.47","southernmostLatitude":"-78.47","westernmostLongitude":"106.8"}},"locationName":"Continent>Antarctica","mappable":"Y","paleoData":[{"NOAADataTableId":"34693","coreLengthMeters":36,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>age control"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017age.txt","linkText":"Vostok 4G-2 61-58KYr Depth/Gas Age","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age>gas age"}]}],"dataTableName":"Vostok2017age","dataTableNotes":null,"earliestYear":6002,"earliestYearBP":6002,"earliestYearCE":-4052,"mostRecentYear":57907,"mostRecentYearBP":57907,"mostRecentYearCE":-55957,"species":[],"timeUnit":"cal yr BP"},{"NOAADataTableId":"34694","coreLengthMeters":36,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>atmospheric gas"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017ch4.txt","linkText":"Vostok 4G-2 61-58KYr Methane Mixing Ratio","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":"corrected for contamination and calibrated","cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":"continuous flow analysis","cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"},{"cvAdditionalInfo":"corrected for contamination and calibrated","cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":"optical feedback cavity enhanced absorption spectroscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"},{"cvAdditionalInfo":"values corresponding to layering artifacts removed","cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":"continuous flow analysis","cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"},{"cvAdditionalInfo":"values corresponding to layering artifacts removed","cvDataType":"ICE CORES","cvDetail":"corrected","cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":"optical feedback cavity enhanced absorption spectroscopy","cvSeasonality":null,"cvShortName":null,"cvUnit":"parts per billion","cvWhat":"chemical composition>compound>organic compound>hydrocarbon>alkane>n-alkane>methane"}]}],"dataTableName":"Vostok2017CH4","dataTableNotes":"This dataset is the high resolution methane mixing ratio measured along a section of the 4G-2 Vostok ice core from East Antarctica; Earliest and most recent years were given according to the AICC2012 gas age scale;","earliestYear":60829,"earliestYearBP":60829,"earliestYearCE":-58879,"mostRecentYear":58118,"mostRecentYearBP":58118,"mostRecentYearCE":-56168,"species":[],"timeUnit":"cal yr BP"},{"NOAADataTableId":"34695","coreLengthMeters":36,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>nitrogen isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017d15n.txt","linkText":"Vostok 4G-2 61-58KYr d15N","urlDescription":"NOAA Template File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":"values measured by mass spectrometry in extracted air after water and CO2 trap and corrected for O2/N2 chemical slope","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"atmospheric material>bulk atmosphere","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil AIR","cvWhat":"chemical composition>isotope>isotope ratio>delta 15N"}]}],"dataTableName":"Vostok2017d15N","dataTableNotes":null,"earliestYear":60829,"earliestYearBP":60829,"earliestYearCE":-58879,"mostRecentYear":58118,"mostRecentYearBP":58118,"mostRecentYearCE":-56168,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Vostok"}],"studyCode":null,"studyName":"Vostok, Antarctica Ice Core 4G-2 61-58KYr Methane and d15N Data","studyNotes":"Vostok, Antarctica 61-58 kY 4G-2 ice core methane mixing ratio.","version":"1.0","xmlId":"21414"}