WAIS Divide Ice Core 67,000 Year Discrete Sample Methane Data Brook, E.J.; Sowers, T. Brook, E.J. Sowers, T. 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 (WAIS Divide WDC06A>LATITUDE -79.4676>LONGITUDE -112.0865) 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 NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Brook, E.J. Investigator : Sowers, T. 2016-01-12 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19662 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osupsu.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-glacial.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-holocene.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4psu.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osupsu.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-glacial.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-holocene.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4psu.txt English https://www.ncdc.noaa.gov/paleo/study/19662 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osupsu.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-glacial.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4osu-holocene.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2015ch4psu.txt WAIS Divide Project Members2015Precise interpolar phasing of abrupt climate change during the last ice ageNature5207459661-66510.1038/nature14401http://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. Brook2014Centennial-scale changes in the global carbon cycle during the last deglaciationNature5157524616-61910.1038/nature13799http://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. Taylor2015The WAIS Divide deep ice core WD2014 chronology - Part 1: Methane synchronization (68-31 ka BP) and the gas age-ice age differenceClimate of the Past112153-17310.5194/cp-11-153-2015http://www.clim-past.net/11/153/2015/cp-11-153-2015.html Logan Mitchell, Ed Brook, James E. Lee, Christo Buizert, Todd Sowers2013Constraints on the Late Holocene Anthropogenic Contribution to the Atmospheric Methane BudgetScience3426161964-96610.1126/science.1238920http://science.sciencemag.org/content/342/6161/964.abstract Logan E. Mitchell, Edward J. Brook, Todd Sowers, J.R. McConnell, Kendrick Taylor2011Multidecadal variability of atmospheric methane, 1000-1800 C.E.Journal of Geophysical Research: Biogeosciences116G210.1029/2010JG001441http://onlinelibrary.wiley.com/doi/10.1029/2010JG001441/full START YEAR: 67145 cal yr BP * END YEAR: 169 cal yr BP -112.0865 -79.4676 -112.0865 -79.4676