noaa-icecore-19662 WAIS Divide Ice Core 67,000 Year Discrete Sample Methane Data Brook, E.J.; Sowers, T. WAIS Divide Ice Core 67,000 Year Discrete Sample Methane Data 2016-01-12 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/19662 Investigator E.J. Brook Investigator T. Sowers earth science paleoclimate ice cores notes,null,null,null,null,ice cores,null,null,C,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,range,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography - flame ionization detection,N,null earth science paleoclimate climate forcing|ice cores methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography - flame ionization detection,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,null,parts per billion,null,climate forcing|ice cores,corrected,gas chromatography - flame ionization detection,N,All CH4 data are reported on the NOAA04 scale earth science paleoclimate ice cores gas age,null,null,calendar year before present,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,gas chromatography - flame ionization detection,N,Corrections for gas solubility and blank and gravitational enrichment for the Oregon State University data earth science paleoclimate ice core atmospheric gas geoscientificInformation 67145 cal yr BP 169 cal yr BP Complete -79.4676 -79.4676 -112.0865 -112.0865 1806 1806 Continent Antarctica WAIS Divide WDC06A>LATITUDE -79.4676>LONGITUDE -112.0865 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 WAIS Divide Project Members 2015 Nature 520 7459 661-665 10.1038/nature14401 http://www.nature.com/nature/journal/v520/n7549/full/nature14401.html Shaun A. Marcott, Thomas K. Bauska, Christo Buizert, Eric J. Steig, Julia L. Rosen, Kurt M. Cuffey, T.J. Fudge, Jeffery P. Severinghaus, Jinho Ahn, Michael L. Kalk, Joseph R. McConnell, Todd Sowers, Kendrick C. Taylor, James W.C. White, and Edward J. Brook 2014 Nature 515 7524 616-619 10.1038/nature13799 http://www.nature.com/nature/journal/v514/n7524/full/nature13799.html C. Buizert, K. M. Cuffey, J. P. Severinghaus, D. Baggenstos, T. J. Fudge, E. J. Steig, B. R. Markle, M. Winstrup, R. H. Rhodes, E. J. Brook, T. A. Sowers, G. D. Clow, H. Cheng, R. L. Edwards, M. Sigl, J. R. McConnell, and K. C. Taylor 2015 Climate of the Past 11 2 153-173 10.5194/cp-11-153-2015 http://www.clim-past.net/11/153/2015/cp-11-153-2015.html Logan Mitchell, Ed Brook, James E. Lee, Christo Buizert, Todd Sowers 2013 Science 342 6161 964-966 10.1126/science.1238920 http://science.sciencemag.org/content/342/6161/964.abstract Logan E. Mitchell, Edward J. Brook, Todd Sowers, J.R. McConnell, Kendrick Taylor 2011 Journal of Geophysical Research: Biogeosciences 116 G2 10.1029/2010JG001441 http://onlinelibrary.wiley.com/doi/10.1029/2010JG001441/full

Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination (23,000 to 9,000 years ago), however, remains uncertain. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500 years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination, given the strong covariance of CO2 levels and Antarctic temperatures. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models. STUDY NOTES: Methane concentrations from discrete samples of the WAIS Divide Ice Core measured at Penn State University and Oregon State University. All depths in meters below the surface. All methane dry air mixing ratios in nano-mol per mol (ppb) on the NOAA04 scale. Methane data have been corrected for blank offsets, solubility loss, and gravitational fractionation using interpolated d15N or N2 data reported in WAIS Divide Project Members (2015). Concentrations are slightly (less than 0.5 ppb) different in this file than in previous data reports because of an updated gravitational enrichment correction based on the newest d15N of N2 data. All ages are given in years before 1950.0 C.E. (A.D.) on the WD2014 timescale. The Combined WAIS Divide Methane record combines the PSU and OSU data sets, and where they overlap, uses the higher resolution data set. This combined file is the version of choice for users needing a complete discrete WAIS Divide methane data set. WAIS Divide Project Members: Christo Buizert, Betty Adrian, Jinho Ahn, Mary Albert, Richard B. Alley, Daniel Baggenstos, Thomas K. Bauska, Ryan C. Bay, Brian B. Bencivengo, Charles R. Bentley, Edward J. Brook, Nathan J. Chellman, Gary D. Clow, Jihong Cole-Dai, Howard Conway, Eric Cravens, Kurt M. Cuffey, Nelia W. Dunbar, Jon S. Edwards, John M. Fegyveresi, Dave G. Ferris, Joan J. Fitzpatrick, T. J. Fudge, Chris J. Gibson, Vasileios Gkinis, Joshua J. Goetz, Stephanie Gregory, Geoffrey M. Hargreaves, Nels Iverson, Jay A. Johnson, Tyler R. Jones, Michael L. Kalk, Matthew J. Kippenhan, Bess G. Koffman, Karl Kreutz, Tanner W. Kuhl, Donald A. Lebar, James E. Lee, Shaun A. Marcott, Bradley R. Markle, Olivia J. Maselli, Joseph R. McConnell, Kenneth C. McGwire, Logan E. Mitchell, Nicolai B. Mortensen, Peter D. Neff, Kunihiko Nishiizumi, Richard M. Nunn, Anais J. Orsi, Daniel R. Pasteris, Joel B. Pedro, Erin C. Pettit, P. Buford Price, John C. Priscu, Rachael H. Rhodes, Julia L. Rosen, Andrew J. Schauer, Spruce W. Schoenemann, Paul J. Sendelbach, Jeffrey P. Severinghaus, Alexander J. Shturmakov, Michael Sigl, Kristina R. Slawny, Joseph M. Souney, Todd A. Sowers, Matthew K. Spencer, Eric J. Steig, Kendrick C. Taylor, Mark S. Twickler, Bruce H. Vaughn, Donald E. Voigt, Edwin D. Waddington, Kees C. Welten, Anthony W. Wendricks, James W. C. White, Mai Winstrup, Gifford J. Wong and Thomas E. Woodruff

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osupsu.txt Data File; WAIS Divide Discrete Sample Methane Data - Combined OSU-PSU Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-glacial.txt Data File; WAIS Divide Discrete Sample Methane Data - OSU Glacial GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-holocene.txt Data File; WAIS Divide Discrete Sample Methane Data - OSU Holocene GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4psu.txt Data File; WAIS Divide Discrete Sample Methane Data - PSU Data USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11