noaa-icecore-18095 North Greenland Eemian (NEEM) Ice Core 107KYr High-Resolution Methane Data Chappellaz, J.A.; Stowasser, C.; Blunier, T.; Baslev-Clausen, D.; Brook, E.J.; Dallmayr, R.; Faïn, X.; Lee, J.-E.; Mitchell, L.E.; Pascual, O.; Romanini, D.; Rosen, J.; Schüpbach, S. North Greenland Eemian (NEEM) Ice Core 107KYr High-Resolution Methane Data 2015-02-25 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/18095 Investigator J.A. Chappellaz Investigator C. Stowasser Investigator T. Blunier Investigator D. Baslev-Clausen Investigator E.J. Brook Investigator R. Dallmayr Investigator X. Faïn Investigator J.-E. Lee Investigator L.E. Mitchell Investigator O. Pascual Investigator D. Romanini Investigator J. Rosen Investigator S. Schüpbach earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,one standard error,parts per billion,null,climate forcing|ice cores,corrected,cavity ring-down spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,null,cavity ring-down spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,null,optical feedback cavity enhanced absorption spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,cavity ring-down spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected|smoothed,optical feedback cavity enhanced absorption spectroscopy,N,null earth science paleoclimate ice cores gas age,null,null,calendar year before present,null,ice cores,null,null,N,Present is 2000 AD earth science paleoclimate ice cores number of samples,null,null,count,null,ice cores,null,null,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,optical feedback cavity enhanced absorption spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,smoothed,cavity ring-down spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected|smoothed,cavity ring-down spectroscopy,N,null earth science paleoclimate ice cores depth,null,null,meter,null,ice cores,null,null,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,one standard error,parts per billion,null,climate forcing|ice cores,null,optical feedback cavity enhanced absorption spectroscopy,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,smoothed,optical feedback cavity enhanced absorption spectroscopy,N,null earth science paleoclimate ice core atmospheric gas geoscientificInformation 107667 cal yr BP 9527 cal yr BP Complete 77.45 77.45 -51.06 -51.06 Continent North America Greenland NEEM>LATITUDE 77.45>LONGITUDE -51.06 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 J. Chappellaz, C. Stowasser, T. Blunier, D. Baslev-Clausen, E.J. Brook, R. Dallmayr, X. Faïn, J.E. Lee, L.E. Mitchell, O. Pascual, D. Romanini, J. Rosen, and S. Schüpbach 2013 Climate of the Past 9 6 2579-2593 10.5194/cp-9-2579-2013 http://www.clim-past.net/9/2579/2013/cp-9-2579-2013.html

The Greenland NEEM (North Greenland Eemian Ice Drilling) operation in 2010 provided the first opportunity to combine trace-gas measurements by laser spectroscopic instruments and continuous-flow analysis along a freshly drilled ice core in a field-based setting. We present the resulting atmospheric methane (CH4) record covering the time period from 107.7 to 9.5 ka b2k (thousand years before 2000 AD). Companion discrete CH4 measurements are required to transfer the laser spectroscopic data from a relative to an absolute scale. However, even on a relative scale, the high-resolution CH4 data set significantly improves our knowledge of past atmospheric methane concentration changes. New significant sub-millennial-scale features appear during interstadials and stadials, generally associated with similar changes in water isotopic ratios of the ice, a proxy for local temperature. In addition to the midpoint of Dansgaard-Oeschger (D/O) CH4 transitions usually used for cross-dating, sharp definition of the start and end of these events brings precise depth markers (with +/- 20 cm uncertainty) for further cross-dating with other palaeo- or ice core records, e.g. speleothems. The method also provides an estimate of CH4 rates of change. The onsets of D/O events in the methane signal show a more rapid rate of change than their endings. The rate of CH4 increase associated with the onsets of D/O events progressively declines from 1.7 to 0.6 ppbv yr-1 in the course of marine isotope stage 3. The largest observed rate of increase takes place at the onset of D/O event 21 and reaches 2.5 ppbv yr-1. STUDY NOTES: High-resolution methane (CH4) data from the North Greenland Eemian (NEEM) ice core for the time period 107.7 to 9.5 ka b2k.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4.zip Data File; NEEM CH4 Continuous and 20cm Averages - All Data ZIP file GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4section-mean.txt Data File; NEEM CH4 WS-CRDS vs. OF-CEAS Differences GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4ofceas-mean.txt Data File; NEEM CH4 OF-CEAS ~20cm means GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4ofceas-cont.txt Data File; NEEM CH4 OF-CEAS Continuous measurements (Large File 37MB) GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4wscrds-mean.txt Data File; NEEM CH4 WS-CRDS ~20cm means GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2013ch4wscrds-cont.txt Data File; NEEM CH4 WS-CRDS Continuous measurements (Large File 23MB) USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11