Articles | Volume 9, issue 6
https://doi.org/10.5194/cp-9-2579-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/cp-9-2579-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
14 Nov 2013
Research article |
| 14 Nov 2013
High-resolution glacial and deglacial record of atmospheric methane by continuous-flow and laser spectrometer analysis along the NEEM ice core
J. Chappellaz
UJF – Grenoble 1/CNRS, UMR5183, CNRS – Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, France
C. Stowasser
Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
T. Blunier
Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
D. Baslev-Clausen
Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
E. J. Brook
College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
R. Dallmayr
UJF – Grenoble 1/CNRS, UMR5183, CNRS – Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, France
now at: National Institute of Polar Research, Tokyo, Japan
UJF – Grenoble 1/CNRS, UMR5183, CNRS – Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, France
J. E. Lee
College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
L. E. Mitchell
College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
O. Pascual
UJF – Grenoble 1/CNRS, UMR5183, CNRS – Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, France
D. Romanini
UJF – Grenoble 1/CNRS, LIPhy UMR5588, Grenoble, France
J. Rosen
College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
S. Schüpbach
Physics Institute, Climate and Environmental Physics and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
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Sarah Shackleton, James A. Menking, Edward Brook, Christo Buizert, Michael N. Dyonisius, Vasilii V. Petrenko, Daniel Baggenstos, and Jeffrey P. Severinghaus
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In this study, we measure atmospheric noble gases trapped in ice cores to reconstruct ocean temperature during the last glaciation. Comparing the new reconstruction to other climate records, we show that the ocean reached its coldest temperatures before ice sheets reached maximum volumes and atmospheric CO2 reached its lowest concentrations. Ocean cooling played a major role in lowering atmospheric CO2 early in the glaciation, but it only played a minor role later.
Yuzhen Yan, Nicole E. Spaulding, Michael L. Bender, Edward J. Brook, John A. Higgins, Andrei V. Kurbatov, and Paul A. Mayewski
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Naoko Nagatsuka, Kumiko Goto-Azuma, Akane Tsushima, Koji Fujita, Sumito Matoba, Yukihiko Onuma, Remi Dallmayr, Moe Kadota, Motohiro Hirabayashi, Jun Ogata, Yoshimi Ogawa-Tsukagawa, Kyotaro Kitamura, Masahiro Minowa, Yuki Komuro, Hideaki Motoyama, and Teruo Aoki
Clim. Past, 17, 1341–1362, https://doi.org/10.5194/cp-17-1341-2021, https://doi.org/10.5194/cp-17-1341-2021, 2021
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Andreas Plach, Bo M. Vinther, Kerim H. Nisancioglu, Sindhu Vudayagiri, and Thomas Blunier
Clim. Past, 17, 317–330, https://doi.org/10.5194/cp-17-317-2021, https://doi.org/10.5194/cp-17-317-2021, 2021
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warmer-than-present period of the past. Our simulations show more
extensive melt than today. This is important for the interpretation of
ice cores which are used to reconstruct the evolution of the ice sheet
and the climate.
Ikumi Oyabu, Kenji Kawamura, Kyotaro Kitamura, Remi Dallmayr, Akihiro Kitamura, Chikako Sawada, Jeffrey P. Severinghaus, Ross Beaudette, Anaïs Orsi, Satoshi Sugawara, Shigeyuki Ishidoya, Dorthe Dahl-Jensen, Kumiko Goto-Azuma, Shuji Aoki, and Takakiyo Nakazawa
Atmos. Meas. Tech., 13, 6703–6731, https://doi.org/10.5194/amt-13-6703-2020, https://doi.org/10.5194/amt-13-6703-2020, 2020
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Jenna A. Epifanio, Edward J. Brook, Christo Buizert, Jon S. Edwards, Todd A. Sowers, Emma C. Kahle, Jeffrey P. Severinghaus, Eric J. Steig, Dominic A. Winski, Erich C. Osterberg, Tyler J. Fudge, Murat Aydin, Ekaterina Hood, Michael Kalk, Karl J. Kreutz, David G. Ferris, and Joshua A. Kennedy
Clim. Past, 16, 2431–2444, https://doi.org/10.5194/cp-16-2431-2020, https://doi.org/10.5194/cp-16-2431-2020, 2020
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James E. Lee, Edward J. Brook, Nancy A. N. Bertler, Christo Buizert, Troy Baisden, Thomas Blunier, V. Gabriela Ciobanu, Howard Conway, Dorthe Dahl-Jensen, Tyler J. Fudge, Richard Hindmarsh, Elizabeth D. Keller, Frédéric Parrenin, Jeffrey P. Severinghaus, Paul Vallelonga, Edwin D. Waddington, and Mai Winstrup
Clim. Past, 16, 1691–1713, https://doi.org/10.5194/cp-16-1691-2020, https://doi.org/10.5194/cp-16-1691-2020, 2020
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Anders Svensson, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Thomas Blunier, Sune O. Rasmussen, Bo M. Vinther, Paul Vallelonga, Emilie Capron, Vasileios Gkinis, Eliza Cook, Helle Astrid Kjær, Raimund Muscheler, Sepp Kipfstuhl, Frank Wilhelms, Thomas F. Stocker, Hubertus Fischer, Florian Adolphi, Tobias Erhardt, Michael Sigl, Amaelle Landais, Frédéric Parrenin, Christo Buizert, Joseph R. McConnell, Mirko Severi, Robert Mulvaney, and Matthias Bigler
Clim. Past, 16, 1565–1580, https://doi.org/10.5194/cp-16-1565-2020, https://doi.org/10.5194/cp-16-1565-2020, 2020
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We identify signatures of large bipolar volcanic eruptions in Greenland and Antarctic ice cores during the last glacial period, which allows for a precise temporal alignment of the ice cores. Thereby the exact timing of unexplained, abrupt climatic changes occurring during the last glacial period can be determined in a global context. The study thus provides a step towards a full understanding of elements of the climate system that may also play an important role in the future.
Stephen J. Harris, Jesper Liisberg, Longlong Xia, Jing Wei, Kerstin Zeyer, Longfei Yu, Matti Barthel, Benjamin Wolf, Bryce F. J. Kelly, Dioni I. Cendón, Thomas Blunier, Johan Six, and Joachim Mohn
Atmos. Meas. Tech., 13, 2797–2831, https://doi.org/10.5194/amt-13-2797-2020, https://doi.org/10.5194/amt-13-2797-2020, 2020
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The latest commercial laser spectrometers have the potential to revolutionize N2O isotope analysis. However, to do so, they must be able to produce trustworthy data. Here, we test the performance of widely used laser spectrometers for ambient air applications and identify instrument-specific dependencies on gas matrix and trace gas concentrations. We then provide a calibration workflow to facilitate the operation of these instruments in order to generate reproducible and accurate data.
Kévin Fourteau, Laurent Arnaud, Xavier Faïn, Patricia Martinerie, David M. Etheridge, Vladimir Lipenkov, and Jean-Marc Barnola
Earth Syst. Sci. Data, 12, 1171–1177, https://doi.org/10.5194/essd-12-1171-2020, https://doi.org/10.5194/essd-12-1171-2020, 2020
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Measurements of the porosity of three polar firns were conducted in the 1990s by Jean-Marc Barnola using the method of gas pycnometry. From these data, a parametrization of firn pore closure was produced and used in different published articles. However, the data have not been published in their own right yet. We have made the data publicly accessible on the PANGAEA database and here propose describing how they were obtained and used to produce the pore closure parametrization.
Kévin Fourteau, Patricia Martinerie, Xavier Faïn, Alexey A. Ekaykin, Jérôme Chappellaz, and Vladimir Lipenkov
Clim. Past, 16, 503–522, https://doi.org/10.5194/cp-16-503-2020, https://doi.org/10.5194/cp-16-503-2020, 2020
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We quantify how the greenhouse gas records of East Antarctic ice cores (which are the oldest ice cores) might differ from the actual atmosphere history. It is required to properly interpret ice core data. For this, we measured the methane of five new East Antarctic ice core sections using a high-resolution technique. We found that in these very old ice cores, one can retrieve concentration variations occurring in only a few centuries, allowing climatologists to study climate's fast dynamics.
Kévin Fourteau, Patricia Martinerie, Xavier Faïn, Christoph F. Schaller, Rebecca J. Tuckwell, Henning Löwe, Laurent Arnaud, Olivier Magand, Elizabeth R. Thomas, Johannes Freitag, Robert Mulvaney, Martin Schneebeli, and Vladimir Ya. Lipenkov
The Cryosphere, 13, 3383–3403, https://doi.org/10.5194/tc-13-3383-2019, https://doi.org/10.5194/tc-13-3383-2019, 2019
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Understanding gas trapping in polar ice is essential to study the relationship between greenhouse gases and past climates. New data of bubble closure, used in a simple gas-trapping model, show inconsistency with the final air content in ice. This suggests gas trapping is not fully understood. We also use a combination of high-resolution measurements to investigate the effect of polar snow stratification on gas trapping and find that all strata have similar pores, but that some close in advance.
Hubertus Fischer, Jochen Schmitt, Michael Bock, Barbara Seth, Fortunat Joos, Renato Spahni, Sebastian Lienert, Gianna Battaglia, Benjamin D. Stocker, Adrian Schilt, and Edward J. Brook
Biogeosciences, 16, 3997–4021, https://doi.org/10.5194/bg-16-3997-2019, https://doi.org/10.5194/bg-16-3997-2019, 2019
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N2O concentrations were subject to strong variations accompanying glacial–interglacial but also rapid climate changes over the last 21 kyr. The sources of these N2O changes can be identified by measuring the isotopic composition of N2O in ice cores and using the distinct isotopic composition of terrestrial and marine N2O. We show that both marine and terrestrial sources increased from the last glacial to the Holocene but that only terrestrial emissions responded quickly to rapid climate changes.
Damiano Della Lunga, Hörhold Maria, Birthe Twarloh, Behrens Melanie, Dallmayr Remi, Erhardt Tobias, Jensen Camille Marie, and Wilhelms Frank
The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-215, https://doi.org/10.5194/tc-2019-215, 2019
Preprint withdrawn
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The extent of sea ice plays a major role in the present Arctic warming, and it is possibly one of its first victims, since it has been predicted to disappear in the near future, if warming proceed. Our manuscript validates ice core proxies for the reconstruction of the variability of sea ice extent around Greenland in the last 600 years, and simultanesouly infers the evolution of the proxy-sources with time. Understanding past sea ice extent variability, is thus crucial in predicting its future.
Dominic A. Winski, Tyler J. Fudge, David G. Ferris, Erich C. Osterberg, John M. Fegyveresi, Jihong Cole-Dai, Zayta Thundercloud, Thomas S. Cox, Karl J. Kreutz, Nikolas Ortman, Christo Buizert, Jenna Epifanio, Edward J. Brook, Ross Beaudette, Jeffrey Severinghaus, Todd Sowers, Eric J. Steig, Emma C. Kahle, Tyler R. Jones, Valerie Morris, Murat Aydin, Melinda R. Nicewonger, Kimberly A. Casey, Richard B. Alley, Edwin D. Waddington, Nels A. Iverson, Nelia W. Dunbar, Ryan C. Bay, Joseph M. Souney, Michael Sigl, and Joseph R. McConnell
Clim. Past, 15, 1793–1808, https://doi.org/10.5194/cp-15-1793-2019, https://doi.org/10.5194/cp-15-1793-2019, 2019
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A deep ice core was recently drilled at the South Pole to understand past variations in the Earth's climate. To understand the information contained within the ice, we present the relationship between the depth and age of the ice in the South Pole Ice Core. We found that the oldest ice in our record is from 54 302 ± 519 years ago. Our results show that, on average, 7.4 cm of snow falls at the South Pole each year.
James A. Menking, Edward J. Brook, Sarah A. Shackleton, Jeffrey P. Severinghaus, Michael N. Dyonisius, Vasilii Petrenko, Joseph R. McConnell, Rachael H. Rhodes, Thomas K. Bauska, Daniel Baggenstos, Shaun Marcott, and Stephen Barker
Clim. Past, 15, 1537–1556, https://doi.org/10.5194/cp-15-1537-2019, https://doi.org/10.5194/cp-15-1537-2019, 2019
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An ice core from Taylor Glacier, Antarctica, spans a period ~ 70 000 years ago when Earth entered the last ice age. Chemical analyses of the ice and air bubbles allow for an independent determination of the ages of the ice and gas bubbles. The difference between the age of the ice and the bubbles at any given depth, called ∆age, is unusually high in the Taylor Glacier core compared to the Taylor Dome ice core situated to the south. This implies a dramatic accumulation gradient between the sites.
Jai Chowdhry Beeman, Léa Gest, Frédéric Parrenin, Dominique Raynaud, Tyler J. Fudge, Christo Buizert, and Edward J. Brook
Clim. Past, 15, 913–926, https://doi.org/10.5194/cp-15-913-2019, https://doi.org/10.5194/cp-15-913-2019, 2019
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Atmospheric CO2 was likely an important amplifier of global-scale orbitally-driven warming during the last deglaciation. However, the mechanisms responsible for the rise in CO2, and the coherent rise in Antarctic isotopic temperature records, are under debate. Using a stochastic method, we detect variable lags between coherent changes in Antarctic temperature and CO2. This implies that the climate mechanisms linking the two records changed or experienced modulations during the deglaciation.
Tobias Erhardt, Emilie Capron, Sune Olander Rasmussen, Simon Schüpbach, Matthias Bigler, Florian Adolphi, and Hubertus Fischer
Clim. Past, 15, 811–825, https://doi.org/10.5194/cp-15-811-2019, https://doi.org/10.5194/cp-15-811-2019, 2019
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The cause of the rapid warming events documented in proxy records across the Northern Hemisphere during the last glacial has been a long-standing puzzle in paleo-climate research. Here, we use high-resolution ice-core data from to cores in Greenland to investigate the progression during the onset of these events on multi-annual timescales to test their plausible triggers. We show that atmospheric circulation changes preceded the warming in Greenland and the collapse of the sea ice by a decade.
Mai Winstrup, Paul Vallelonga, Helle A. Kjær, Tyler J. Fudge, James E. Lee, Marie H. Riis, Ross Edwards, Nancy A. N. Bertler, Thomas Blunier, Ed J. Brook, Christo Buizert, Gabriela Ciobanu, Howard Conway, Dorthe Dahl-Jensen, Aja Ellis, B. Daniel Emanuelsson, Richard C. A. Hindmarsh, Elizabeth D. Keller, Andrei V. Kurbatov, Paul A. Mayewski, Peter D. Neff, Rebecca L. Pyne, Marius F. Simonsen, Anders Svensson, Andrea Tuohy, Edwin D. Waddington, and Sarah Wheatley
Clim. Past, 15, 751–779, https://doi.org/10.5194/cp-15-751-2019, https://doi.org/10.5194/cp-15-751-2019, 2019
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We present a 2700-year timescale and snow accumulation history for an ice core from Roosevelt Island, Ross Ice Shelf, Antarctica. We observe a long-term slightly decreasing trend in accumulation during most of the period but a rapid decline since the mid-1960s. The latter is linked to a recent strengthening of the Amundsen Sea Low and the expansion of regional sea ice. The year 1965 CE may thus mark the onset of significant increases in sea-ice extent in the eastern Ross Sea.
Jonas Beck, Michael Bock, Jochen Schmitt, Barbara Seth, Thomas Blunier, and Hubertus Fischer
Biogeosciences, 15, 7155–7175, https://doi.org/10.5194/bg-15-7155-2018, https://doi.org/10.5194/bg-15-7155-2018, 2018
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Ice core concentration and stable isotope measurements of atmospheric CH4 give valuable insights into the CH4 cycle of the past. New carbon and hydrogen stable isotope CH4 data measured on ice from both Greenland and Antarctica over the Holocene allow us to draw conclusions on the methane emission processes. In particular, our results cast doubt on a hypothesis proposing early human land use to be responsible for the atmospheric methane concentration increase in the second half of the Holocene.
Taku Umezawa, Carl A. M. Brenninkmeijer, Thomas Röckmann, Carina van der Veen, Stanley C. Tyler, Ryo Fujita, Shinji Morimoto, Shuji Aoki, Todd Sowers, Jochen Schmitt, Michael Bock, Jonas Beck, Hubertus Fischer, Sylvia E. Michel, Bruce H. Vaughn, John B. Miller, James W. C. White, Gordon Brailsford, Hinrich Schaefer, Peter Sperlich, Willi A. Brand, Michael Rothe, Thomas Blunier, David Lowry, Rebecca E. Fisher, Euan G. Nisbet, Andrew L. Rice, Peter Bergamaschi, Cordelia Veidt, and Ingeborg Levin
Atmos. Meas. Tech., 11, 1207–1231, https://doi.org/10.5194/amt-11-1207-2018, https://doi.org/10.5194/amt-11-1207-2018, 2018
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Isotope measurements are useful for separating different methane sources. However, the lack of widely accepted standards and calibration methods for stable carbon and hydrogen isotopic ratios of methane in air has caused significant measurement offsets among laboratories. We conducted worldwide interlaboratory comparisons, surveyed the literature and assessed them systematically. This study may be of help in future attempts to harmonize data sets of isotopic composition of atmospheric methane.
Nancy A. N. Bertler, Howard Conway, Dorthe Dahl-Jensen, Daniel B. Emanuelsson, Mai Winstrup, Paul T. Vallelonga, James E. Lee, Ed J. Brook, Jeffrey P. Severinghaus, Taylor J. Fudge, Elizabeth D. Keller, W. Troy Baisden, Richard C. A. Hindmarsh, Peter D. Neff, Thomas Blunier, Ross Edwards, Paul A. Mayewski, Sepp Kipfstuhl, Christo Buizert, Silvia Canessa, Ruzica Dadic, Helle A. Kjær, Andrei Kurbatov, Dongqi Zhang, Edwin D. Waddington, Giovanni Baccolo, Thomas Beers, Hannah J. Brightley, Lionel Carter, David Clemens-Sewall, Viorela G. Ciobanu, Barbara Delmonte, Lukas Eling, Aja Ellis, Shruthi Ganesh, Nicholas R. Golledge, Skylar Haines, Michael Handley, Robert L. Hawley, Chad M. Hogan, Katelyn M. Johnson, Elena Korotkikh, Daniel P. Lowry, Darcy Mandeno, Robert M. McKay, James A. Menking, Timothy R. Naish, Caroline Noerling, Agathe Ollive, Anaïs Orsi, Bernadette C. Proemse, Alexander R. Pyne, Rebecca L. Pyne, James Renwick, Reed P. Scherer, Stefanie Semper, Marius Simonsen, Sharon B. Sneed, Eric J. Steig, Andrea Tuohy, Abhijith Ulayottil Venugopal, Fernando Valero-Delgado, Janani Venkatesh, Feitang Wang, Shimeng Wang, Dominic A. Winski, V. Holly L. Winton, Arran Whiteford, Cunde Xiao, Jiao Yang, and Xin Zhang
Clim. Past, 14, 193–214, https://doi.org/10.5194/cp-14-193-2018, https://doi.org/10.5194/cp-14-193-2018, 2018
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Temperature and snow accumulation records from the annually dated Roosevelt Island Climate Evolution (RICE) ice core show that for the past 2 700 years, the eastern Ross Sea warmed, while the western Ross Sea showed no trend and West Antarctica cooled. From the 17th century onwards, this dipole relationship changed. Now all three regions show concurrent warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea.
Malte Winther, David Balslev-Harder, Søren Christensen, Anders Priemé, Bo Elberling, Eric Crosson, and Thomas Blunier
Biogeosciences, 15, 767–780, https://doi.org/10.5194/bg-15-767-2018, https://doi.org/10.5194/bg-15-767-2018, 2018
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Nitrous oxide (N2O) is an important and strong greenhouse gas in the atmosphere and part of climate. N2O is produced by microbes in terrestrial and aquatic ecosystems. The properties of each specific molecule can be used to determine the source. We implemented continuous measurements of N2O during incubation of denitrifying bacteria and believe that similar experiments will lead to a better understanding of N2O turnover and on the biotic mechanisms behind greenhouse gas exchange of the globe.
Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz
Clim. Past, 13, 1815–1830, https://doi.org/10.5194/cp-13-1815-2017, https://doi.org/10.5194/cp-13-1815-2017, 2017
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We measured methane concentrations from a polar ice core to quantify the differences between the ice record and the past true atmospheric conditions. Two effects were investigated by combining data analysis and modeling: the stratification of polar snow before gas enclosure driving chronological hiatuses in the record and the gradual formation of bubbles in the ice attenuating fast atmospheric variations. This study will contribute to improving future climatic interpretations from ice archives.
Ji-Woong Yang, Jinho Ahn, Edward J. Brook, and Yeongjun Ryu
Clim. Past, 13, 1227–1242, https://doi.org/10.5194/cp-13-1227-2017, https://doi.org/10.5194/cp-13-1227-2017, 2017
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The early Holocene climate is characterized as an interglacial boundary condition without substantial human influence. Here we present a high-resolution CH4 record covering the early Holocene. The results show that abrupt cooling in Greenland and southward migration of ITCZ were able to induce an ~20 ppb CH4 decrease on a millennial timescale. The inter-polar difference exhibits a gradual increase during the early Holocene, implying the strengthening of northern extratropical emission.
Léa Gest, Frédéric Parrenin, Jai Chowdhry Beeman, Dominique Raynaud, Tyler J. Fudge, Christo Buizert, and Edward J. Brook
Clim. Past Discuss., https://doi.org/10.5194/cp-2017-71, https://doi.org/10.5194/cp-2017-71, 2017
Revised manuscript has not been submitted
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In this manuscript, we place the atmospheric CO2 and Antarctic temperature records onto a common age scale during the last deglaciation. Moreover, we evaluate the phase relationship between those two records in order to discuss possible climatic and carbon cycle scenarios. Indeed, this phase relationship is central to determine the role of the former in past (and therefore future) climatic variations. This scientific problem was even discussed by some policy makers (e.g., in the USA senate).
Irène Ventrillard, Irène Xueref-Remy, Martina Schmidt, Camille Yver Kwok, Xavier Faïn, and Daniele Romanini
Atmos. Meas. Tech., 10, 1803–1812, https://doi.org/10.5194/amt-10-1803-2017, https://doi.org/10.5194/amt-10-1803-2017, 2017
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We present a comparison of CO measurements performed with a portable OF-CEAS laser spectrometer against a high-performance gas chromatograph. For both surface and airborne measurements, the instruments show an excellent agreement very close to the 2 ppb World Meteorological Organization recommendation for CO inter-laboratory comparison. This work establishes that this laser technique allows for the development of sensitive, compact, robust and reliable instruments for in situ trace-gas analysis.
Markella Prokopiou, Patricia Martinerie, Célia J. Sapart, Emmanuel Witrant, Guillaume Monteil, Kentaro Ishijima, Sophie Bernard, Jan Kaiser, Ingeborg Levin, Thomas Blunier, David Etheridge, Ed Dlugokencky, Roderik S. W. van de Wal, and Thomas Röckmann
Atmos. Chem. Phys., 17, 4539–4564, https://doi.org/10.5194/acp-17-4539-2017, https://doi.org/10.5194/acp-17-4539-2017, 2017
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Nitrous oxide is the third most important anthropogenic greenhouse gas with an increasing mole fraction. To understand its natural and anthropogenic sources
we employ isotope measurements. Results show that while the N2O mole fraction increases, its heavy isotope content decreases. The isotopic changes observed underline the dominance of agricultural emissions especially at the early part of the record, whereas in the later decades the contribution from other anthropogenic sources increases.
Saehee Lim, Xavier Faïn, Patrick Ginot, Vladimir Mikhalenko, Stanislav Kutuzov, Jean-Daniel Paris, Anna Kozachek, and Paolo Laj
Atmos. Chem. Phys., 17, 3489–3505, https://doi.org/10.5194/acp-17-3489-2017, https://doi.org/10.5194/acp-17-3489-2017, 2017
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A record of light-absorbing refractory black carbon (rBC), emitted by fossil fuel combustion and biomass burning, was reconstructed from the ice cores drilled at a high-altitude eastern European site in Mt. Elbrus. This record reports for the first time the high-resolution rBC mass concentrations in the European outflows over the past 189 years. Our study suggests that the past changes in BC emissions of eastern Europe need to be considered in assessing ongoing air quality regulations.
Michel Legrand, Joseph McConnell, Hubertus Fischer, Eric W. Wolff, Susanne Preunkert, Monica Arienzo, Nathan Chellman, Daiana Leuenberger, Olivia Maselli, Philip Place, Michael Sigl, Simon Schüpbach, and Mike Flannigan
Clim. Past, 12, 2033–2059, https://doi.org/10.5194/cp-12-2033-2016, https://doi.org/10.5194/cp-12-2033-2016, 2016
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Here, we review previous attempts made to reconstruct past forest fire using chemical signals recorded in Greenland ice. We showed that the Greenland ice records of ammonium, found to be a good fire proxy, consistently indicate changing fire activity in Canada in response to past climatic conditions that occurred since the last 15 000 years, including the Little Ice Age and the last large climatic transition.
Cathy M. Trudinger, Paul J. Fraser, David M. Etheridge, William T. Sturges, Martin K. Vollmer, Matt Rigby, Patricia Martinerie, Jens Mühle, David R. Worton, Paul B. Krummel, L. Paul Steele, Benjamin R. Miller, Johannes Laube, Francis S. Mani, Peter J. Rayner, Christina M. Harth, Emmanuel Witrant, Thomas Blunier, Jakob Schwander, Simon O'Doherty, and Mark Battle
Atmos. Chem. Phys., 16, 11733–11754, https://doi.org/10.5194/acp-16-11733-2016, https://doi.org/10.5194/acp-16-11733-2016, 2016
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Perfluorocarbons (PFCs) are potent, long-lived and mostly man-made greenhouse gases released to the atmosphere mainly during aluminium production and semiconductor manufacture. Here we present the first continuous histories of three PFCs from 1800 to 2014, derived from measurements of these PFCs in the atmosphere and in air bubbles in polar ice. The records show how human actions have affected these important greenhouse gases over the past century.
Peter Sperlich, Nelly A. M. Uitslag, Jürgen M. Richter, Michael Rothe, Heike Geilmann, Carina van der Veen, Thomas Röckmann, Thomas Blunier, and Willi A. Brand
Atmos. Meas. Tech., 9, 3717–3737, https://doi.org/10.5194/amt-9-3717-2016, https://doi.org/10.5194/amt-9-3717-2016, 2016
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Isotope measurements in atmospheric CH4 are performed since more than 3 decades. However, standard gases to harmonize global measurements are not available to this day. We designed two methods to calibrate a suite of 8 CH4 gases with a wide range in isotopic composition to the VPDB and VSMOW scales with high precision and accuracy. Synthetic air mixtures with ~2 ppm of calibrated CH4 can be provided to the community by the ISOLAB of the Max Planck Institute for Biogeochemistry in Jena, Germany.
Theo Manuel Jenk, Mauro Rubino, David Etheridge, Viorela Gabriela Ciobanu, and Thomas Blunier
Atmos. Meas. Tech., 9, 3687–3706, https://doi.org/10.5194/amt-9-3687-2016, https://doi.org/10.5194/amt-9-3687-2016, 2016
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Atmospheric CO2 and δ13C-CO2 records from polar ice cores provide important constraints on the natural carbon cycle variability. Still, data exist only from a limited number of sampling sites and time periods due to demanding analytical challenges. Additional analytical state-of-the-art resources are desirable. This study describes such a new facility. Its analytical performance and new approaches for dealing with procedural blank contribution and analytical outliers are discussed in detail.
Malte Winther, David Balslev-Harder, Søren Christensen, Anders Priemé, Bo Elberling, Eric Crosson, and Thomas Blunier
Biogeosciences Discuss., https://doi.org/10.5194/bg-2016-258, https://doi.org/10.5194/bg-2016-258, 2016
Revised manuscript not accepted
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Nitrous oxide (N2O) is an important and strong greenhouse gas in the atmosphere and part of climate. N2O is produced by microbes in terrestrial and aquatic ecosystems. The properties of each specific molecule can be used to determine the source. We implemented continuous measurements of N2O during incubation of denitrifying bacteria and believe that similar experiments will lead to a better understanding of N2O turnover and on the biotic mechanisms behind greenhouse gas exchange of the Globe.
Rachael H. Rhodes, Xavier Faïn, Edward J. Brook, Joseph R. McConnell, Olivia J. Maselli, Michael Sigl, Jon Edwards, Christo Buizert, Thomas Blunier, Jérôme Chappellaz, and Johannes Freitag
Clim. Past, 12, 1061–1077, https://doi.org/10.5194/cp-12-1061-2016, https://doi.org/10.5194/cp-12-1061-2016, 2016
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Local artifacts in ice core methane data are superimposed on consistent records of past atmospheric variability. These artifacts are not related to past atmospheric history and care should be taken to avoid interpreting them as such. By investigating five polar ice cores from sites with different conditions, we relate isolated methane spikes to melt layers and decimetre-scale variations as "trapping signal" associated with a difference in timing of air bubble closure in adjacent firn layers.
L. M. T. Joelsson, J. A. Schmidt, E. J. K. Nilsson, T. Blunier, D. W. T. Griffith, S. Ono, and M. S. Johnson
Atmos. Chem. Phys., 16, 4439–4449, https://doi.org/10.5194/acp-16-4439-2016, https://doi.org/10.5194/acp-16-4439-2016, 2016
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We present experimental kinetic isotope effects (KIE) for the OH oxidation of CH3D and 13CH3D and their temperature dependence. Our determination of the 13CH3D + OH KIE is novel and we find no "clumped" isotope effect within the experimental uncertainty.
Michael Sigl, Tyler J. Fudge, Mai Winstrup, Jihong Cole-Dai, David Ferris, Joseph R. McConnell, Ken C. Taylor, Kees C. Welten, Thomas E. Woodruff, Florian Adolphi, Marion Bisiaux, Edward J. Brook, Christo Buizert, Marc W. Caffee, Nelia W. Dunbar, Ross Edwards, Lei Geng, Nels Iverson, Bess Koffman, Lawrence Layman, Olivia J. Maselli, Kenneth McGwire, Raimund Muscheler, Kunihiko Nishiizumi, Daniel R. Pasteris, Rachael H. Rhodes, and Todd A. Sowers
Clim. Past, 12, 769–786, https://doi.org/10.5194/cp-12-769-2016, https://doi.org/10.5194/cp-12-769-2016, 2016
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Here we present a chronology (WD2014) for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide ice core, which is based on layer counting of distinctive annual cycles preserved in the elemental, chemical and electrical conductivity records. We validated the chronology by comparing it to independent high-accuracy, absolutely dated chronologies. Given its demonstrated high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere.
V. Mikhalenko, S. Sokratov, S. Kutuzov, P. Ginot, M. Legrand, S. Preunkert, I. Lavrentiev, A. Kozachek, A. Ekaykin, X. Faïn, S. Lim, U. Schotterer, V. Lipenkov, and P. Toropov
The Cryosphere, 9, 2253–2270, https://doi.org/10.5194/tc-9-2253-2015, https://doi.org/10.5194/tc-9-2253-2015, 2015
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For the first time an ice core unaffected by melting was recovered from the western Elbrus plateau in the Caucasus. The preserved chemical and isotopic data are considered a source of paleo-climate information for southern/eastern Europe. Considerable snow accumulation (about 1500mm w.e.) and high sampling resolution allowed seasonal variability to be obtained in climate signals, covering a time period of about 200 years. Ice flow models suggest that the basal ice age can be more than 600 years.
C. Reutenauer, A. Landais, T. Blunier, C. Bréant, M. Kageyama, M.-N. Woillez, C. Risi, V. Mariotti, and P. Braconnot
Clim. Past, 11, 1527–1551, https://doi.org/10.5194/cp-11-1527-2015, https://doi.org/10.5194/cp-11-1527-2015, 2015
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Isotopes of atmospheric O2 undergo millennial-scale variations during the last glacial period, and systematically increase during Heinrich stadials.
Such variations are mostly due to vegetation and water cycle processes.
Our modeling approach reproduces the main observed features of Heinrich stadials in terms of climate, vegetation and rainfall.
It highlights the strong role of hydrology on O2 isotopes, which can be seen as a global integrator of precipitation changes over vegetated areas.
A. Svensson, S. Fujita, M. Bigler, M. Braun, R. Dallmayr, V. Gkinis, K. Goto-Azuma, M. Hirabayashi, K. Kawamura, S. Kipfstuhl, H. A. Kjær, T. Popp, M. Simonsen, J. P. Steffensen, P. Vallelonga, and B. M. Vinther
Clim. Past, 11, 1127–1137, https://doi.org/10.5194/cp-11-1127-2015, https://doi.org/10.5194/cp-11-1127-2015, 2015
S. J. Allin, J. C. Laube, E. Witrant, J. Kaiser, E. McKenna, P. Dennis, R. Mulvaney, E. Capron, P. Martinerie, T. Röckmann, T. Blunier, J. Schwander, P. J. Fraser, R. L. Langenfelds, and W. T. Sturges
Atmos. Chem. Phys., 15, 6867–6877, https://doi.org/10.5194/acp-15-6867-2015, https://doi.org/10.5194/acp-15-6867-2015, 2015
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Stratospheric ozone protects life on Earth from harmful UV-B radiation. Chlorofluorocarbons (CFCs) are man-made compounds which act to destroy this barrier.
This paper presents (1) the first measurements of the stratospheric δ(37Cl) of CFCs -11 and -113; (2) the first quantification of long-term trends in the tropospheric δ(37Cl) of CFCs -11, -12 and -113.
This study provides a better understanding of source and sink processes associated with these destructive compounds.
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
Clim. Past, 11, 153–173, https://doi.org/10.5194/cp-11-153-2015, https://doi.org/10.5194/cp-11-153-2015, 2015
M. Guillevic, L. Bazin, A. Landais, C. Stowasser, V. Masson-Delmotte, T. Blunier, F. Eynaud, S. Falourd, E. Michel, B. Minster, T. Popp, F. Prié, and B. M. Vinther
Clim. Past, 10, 2115–2133, https://doi.org/10.5194/cp-10-2115-2014, https://doi.org/10.5194/cp-10-2115-2014, 2014
T. K. Bauska, E. J. Brook, A. C. Mix, and A. Ross
Atmos. Meas. Tech., 7, 3825–3837, https://doi.org/10.5194/amt-7-3825-2014, https://doi.org/10.5194/amt-7-3825-2014, 2014
P. Zennaro, N. Kehrwald, J. R. McConnell, S. Schüpbach, O. J. Maselli, J. Marlon, P. Vallelonga, D. Leuenberger, R. Zangrando, A. Spolaor, M. Borrotti, E. Barbaro, A. Gambaro, and C. Barbante
Clim. Past, 10, 1905–1924, https://doi.org/10.5194/cp-10-1905-2014, https://doi.org/10.5194/cp-10-1905-2014, 2014
G. Gfeller, H. Fischer, M. Bigler, S. Schüpbach, D. Leuenberger, and O. Mini
The Cryosphere, 8, 1855–1870, https://doi.org/10.5194/tc-8-1855-2014, https://doi.org/10.5194/tc-8-1855-2014, 2014
S. Lim, X. Faïn, M. Zanatta, J. Cozic, J.-L. Jaffrezo, P. Ginot, and P. Laj
Atmos. Meas. Tech., 7, 3307–3324, https://doi.org/10.5194/amt-7-3307-2014, https://doi.org/10.5194/amt-7-3307-2014, 2014
X. Faïn, J. Chappellaz, R. H. Rhodes, C. Stowasser, T. Blunier, J. R. McConnell, E. J. Brook, S. Preunkert, M. Legrand, T. Debois, and D. Romanini
Clim. Past, 10, 987–1000, https://doi.org/10.5194/cp-10-987-2014, https://doi.org/10.5194/cp-10-987-2014, 2014
S. O. Rasmussen, P. M. Abbott, T. Blunier, A. J. Bourne, E. Brook, S. L. Buchardt, C. Buizert, J. Chappellaz, H. B. Clausen, E. Cook, D. Dahl-Jensen, S. M. Davies, M. Guillevic, S. Kipfstuhl, T. Laepple, I. K. Seierstad, J. P. Severinghaus, J. P. Steffensen, C. Stowasser, A. Svensson, P. Vallelonga, B. M. Vinther, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 2713–2730, https://doi.org/10.5194/cp-9-2713-2013, https://doi.org/10.5194/cp-9-2713-2013, 2013
H. Fischer, J. Severinghaus, E. Brook, E. Wolff, M. Albert, O. Alemany, R. Arthern, C. Bentley, D. Blankenship, J. Chappellaz, T. Creyts, D. Dahl-Jensen, M. Dinn, M. Frezzotti, S. Fujita, H. Gallee, R. Hindmarsh, D. Hudspeth, G. Jugie, K. Kawamura, V. Lipenkov, H. Miller, R. Mulvaney, F. Parrenin, F. Pattyn, C. Ritz, J. Schwander, D. Steinhage, T. van Ommen, and F. Wilhelms
Clim. Past, 9, 2489–2505, https://doi.org/10.5194/cp-9-2489-2013, https://doi.org/10.5194/cp-9-2489-2013, 2013
P. Sperlich, C. Buizert, T. M. Jenk, C. J. Sapart, M. Prokopiou, T. Röckmann, and T. Blunier
Atmos. Meas. Tech., 6, 2027–2041, https://doi.org/10.5194/amt-6-2027-2013, https://doi.org/10.5194/amt-6-2027-2013, 2013
V. V. Petrenko, P. Martinerie, P. Novelli, D. M. Etheridge, I. Levin, Z. Wang, T. Blunier, J. Chappellaz, J. Kaiser, P. Lang, L. P. Steele, S. Hammer, J. Mak, R. L. Langenfelds, J. Schwander, J. P. Severinghaus, E. Witrant, G. Petron, M. O. Battle, G. Forster, W. T. Sturges, J.-F. Lamarque, K. Steffen, and J. W. C. White
Atmos. Chem. Phys., 13, 7567–7585, https://doi.org/10.5194/acp-13-7567-2013, https://doi.org/10.5194/acp-13-7567-2013, 2013
L. Bazin, A. Landais, B. Lemieux-Dudon, H. Toyé Mahamadou Kele, D. Veres, F. Parrenin, P. Martinerie, C. Ritz, E. Capron, V. Lipenkov, M.-F. Loutre, D. Raynaud, B. Vinther, A. Svensson, S. O. Rasmussen, M. Severi, T. Blunier, M. Leuenberger, H. Fischer, V. Masson-Delmotte, J. Chappellaz, and E. Wolff
Clim. Past, 9, 1715–1731, https://doi.org/10.5194/cp-9-1715-2013, https://doi.org/10.5194/cp-9-1715-2013, 2013
D. Veres, L. Bazin, A. Landais, H. Toyé Mahamadou Kele, B. Lemieux-Dudon, F. Parrenin, P. Martinerie, E. Blayo, T. Blunier, E. Capron, J. Chappellaz, S. O. Rasmussen, M. Severi, A. Svensson, B. Vinther, and E. W. Wolff
Clim. Past, 9, 1733–1748, https://doi.org/10.5194/cp-9-1733-2013, https://doi.org/10.5194/cp-9-1733-2013, 2013
H. C. Steen-Larsen, S. J. Johnsen, V. Masson-Delmotte, B. Stenni, C. Risi, H. Sodemann, D. Balslev-Clausen, T. Blunier, D. Dahl-Jensen, M. D. Ellehøj, S. Falourd, A. Grindsted, V. Gkinis, J. Jouzel, T. Popp, S. Sheldon, S. B. Simonsen, J. Sjolte, J. P. Steffensen, P. Sperlich, A. E. Sveinbjörnsdóttir, B. M. Vinther, and J. W. C. White
Atmos. Chem. Phys., 13, 4815–4828, https://doi.org/10.5194/acp-13-4815-2013, https://doi.org/10.5194/acp-13-4815-2013, 2013
M. Guillevic, L. Bazin, A. Landais, P. Kindler, A. Orsi, V. Masson-Delmotte, T. Blunier, S. L. Buchardt, E. Capron, M. Leuenberger, P. Martinerie, F. Prié, and B. M. Vinther
Clim. Past, 9, 1029–1051, https://doi.org/10.5194/cp-9-1029-2013, https://doi.org/10.5194/cp-9-1029-2013, 2013
E. Capron, A. Landais, D. Buiron, A. Cauquoin, J. Chappellaz, M. Debret, J. Jouzel, M. Leuenberger, P. Martinerie, V. Masson-Delmotte, R. Mulvaney, F. Parrenin, and F. Prié
Clim. Past, 9, 983–999, https://doi.org/10.5194/cp-9-983-2013, https://doi.org/10.5194/cp-9-983-2013, 2013
A. Svensson, M. Bigler, T. Blunier, H. B. Clausen, D. Dahl-Jensen, H. Fischer, S. Fujita, K. Goto-Azuma, S. J. Johnsen, K. Kawamura, S. Kipfstuhl, M. Kohno, F. Parrenin, T. Popp, S. O. Rasmussen, J. Schwander, I. Seierstad, M. Severi, J. P. Steffensen, R. Udisti, R. Uemura, P. Vallelonga, B. M. Vinther, A. Wegner, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 749–766, https://doi.org/10.5194/cp-9-749-2013, https://doi.org/10.5194/cp-9-749-2013, 2013
P. Vallelonga, C. Barbante, G. Cozzi, J. Gabrieli, S. Schüpbach, A. Spolaor, and C. Turetta
Clim. Past, 9, 597–604, https://doi.org/10.5194/cp-9-597-2013, https://doi.org/10.5194/cp-9-597-2013, 2013
C. M. Trudinger, I. G. Enting, P. J. Rayner, D. M. Etheridge, C. Buizert, M. Rubino, P. B. Krummel, and T. Blunier
Atmos. Chem. Phys., 13, 1485–1510, https://doi.org/10.5194/acp-13-1485-2013, https://doi.org/10.5194/acp-13-1485-2013, 2013
Related subject area
Subject: Greenhouse Gases | Archive: Ice Cores | Timescale: Millenial/D-O
Methane, ethane, and propane production in Greenland ice core samples and a first isotopic characterization of excess methane
CH4 and N2O fluctuations during the penultimate deglaciation
An 83 000-year-old ice core from Roosevelt Island, Ross Sea, Antarctica
Antarctic temperature and CO2: near-synchrony yet variable phasing during the last deglaciation
Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low-accumulation conditions
NGRIP CH4 concentration from 120 to 10 kyr before present and its relation to a δ15N temperature reconstruction from the same ice core
Limited response of peatland CH4 emissions to abrupt Atlantic Ocean circulation changes in glacial climates
Enrichment in 13C of atmospheric CH4 during the Younger Dryas termination
A refined TALDICE-1a age scale from 55 to 112 ka before present for the Talos Dome ice core based on high-resolution methane measurements
Michaela Mühl, Jochen Schmitt, Barbara Seth, James E. Lee, Jon S. Edwards, Edward J. Brook, Thomas Blunier, and Hubertus Fischer
Clim. Past, 19, 999–1025, https://doi.org/10.5194/cp-19-999-2023, https://doi.org/10.5194/cp-19-999-2023, 2023
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Our ice core measurements show that methane, ethane, and propane concentrations are significantly elevated above their past atmospheric background for Greenland ice samples containing mineral dust. The underlying co-production process happens during the classical discrete wet extraction of air from the ice sample and affects previous reconstructions of the inter-polar difference of methane as well as methane stable isotope records derived from dust-rich Greenland ice.
Loïc Schmidely, Christoph Nehrbass-Ahles, Jochen Schmitt, Juhyeong Han, Lucas Silva, Jinwha Shin, Fortunat Joos, Jérôme Chappellaz, Hubertus Fischer, and Thomas F. Stocker
Clim. Past, 17, 1627–1643, https://doi.org/10.5194/cp-17-1627-2021, https://doi.org/10.5194/cp-17-1627-2021, 2021
Short summary
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Using ancient gas trapped in polar glaciers, we reconstructed the atmospheric concentrations of methane and nitrous oxide over the penultimate deglaciation to study their response to major climate changes. We show this deglaciation to be characterized by modes of methane and nitrous oxide variability that are also found during the last deglaciation and glacial cycle.
James E. Lee, Edward J. Brook, Nancy A. N. Bertler, Christo Buizert, Troy Baisden, Thomas Blunier, V. Gabriela Ciobanu, Howard Conway, Dorthe Dahl-Jensen, Tyler J. Fudge, Richard Hindmarsh, Elizabeth D. Keller, Frédéric Parrenin, Jeffrey P. Severinghaus, Paul Vallelonga, Edwin D. Waddington, and Mai Winstrup
Clim. Past, 16, 1691–1713, https://doi.org/10.5194/cp-16-1691-2020, https://doi.org/10.5194/cp-16-1691-2020, 2020
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The Roosevelt Island ice core was drilled to investigate climate from the eastern Ross Sea, West Antarctica. We describe the ice age-scale and gas age-scale of the ice core for 0–763 m (83 000 years BP). Old ice near the bottom of the core implies the ice dome existed throughout the last glacial period and that ice streaming was active in the region. Variations in methane, similar to those used as evidence of early human influence on climate, were observed prior to significant human populations.
Jai Chowdhry Beeman, Léa Gest, Frédéric Parrenin, Dominique Raynaud, Tyler J. Fudge, Christo Buizert, and Edward J. Brook
Clim. Past, 15, 913–926, https://doi.org/10.5194/cp-15-913-2019, https://doi.org/10.5194/cp-15-913-2019, 2019
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Atmospheric CO2 was likely an important amplifier of global-scale orbitally-driven warming during the last deglaciation. However, the mechanisms responsible for the rise in CO2, and the coherent rise in Antarctic isotopic temperature records, are under debate. Using a stochastic method, we detect variable lags between coherent changes in Antarctic temperature and CO2. This implies that the climate mechanisms linking the two records changed or experienced modulations during the deglaciation.
Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz
Clim. Past, 13, 1815–1830, https://doi.org/10.5194/cp-13-1815-2017, https://doi.org/10.5194/cp-13-1815-2017, 2017
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We measured methane concentrations from a polar ice core to quantify the differences between the ice record and the past true atmospheric conditions. Two effects were investigated by combining data analysis and modeling: the stratification of polar snow before gas enclosure driving chronological hiatuses in the record and the gradual formation of bubbles in the ice attenuating fast atmospheric variations. This study will contribute to improving future climatic interpretations from ice archives.
M. Baumgartner, P. Kindler, O. Eicher, G. Floch, A. Schilt, J. Schwander, R. Spahni, E. Capron, J. Chappellaz, M. Leuenberger, H. Fischer, and T. F. Stocker
Clim. Past, 10, 903–920, https://doi.org/10.5194/cp-10-903-2014, https://doi.org/10.5194/cp-10-903-2014, 2014
P. O. Hopcroft, P. J. Valdes, R. Wania, and D. J. Beerling
Clim. Past, 10, 137–154, https://doi.org/10.5194/cp-10-137-2014, https://doi.org/10.5194/cp-10-137-2014, 2014
J. R. Melton, H. Schaefer, and M. J. Whiticar
Clim. Past, 8, 1177–1197, https://doi.org/10.5194/cp-8-1177-2012, https://doi.org/10.5194/cp-8-1177-2012, 2012
S. Schüpbach, U. Federer, M. Bigler, H. Fischer, and T. F. Stocker
Clim. Past, 7, 1001–1009, https://doi.org/10.5194/cp-7-1001-2011, https://doi.org/10.5194/cp-7-1001-2011, 2011
Cited articles
Bândǎ, N., Krol, M., van Weele, M., van Noije, T., and Röckmann, T.: Analysis of global methane changes after the 1991 Pinatubo volcanic eruption, Atmos. Chem. Phys., 13, 2267–2281, https://doi.org/10.5194/acp-13-2267-2013, 2013.
Baumgartner, M., Schilt, A., Eicher, O., Schmitt, J., Schwander, J., Spahni, R., Fischer, H., and Stocker, T. F.: High-resolution interpolar difference of atmospheric methane around the Last Glacial Maximum, Biogeosciences, 9, 3961–3977, https://doi.org/10.5194/bg-9-3961-2012, 2012.
Bekki, S. and Law, K. S.: Sensitivity of the atmospheric CH4 growth rate to global temperature changes observed from 1980 to 1992, Tellus Ser. B, 49, 409–416, 1997.
Bekki, S., Pyle, J. A., Zhong, W., Toumi, R., Haigh, J. D., and Pyle, D. M.: The role of microphysical and chemical processes in prolonging the climate forcing of the Toba eruption, Geophys. Res. Lett., 23, 2669–2672, 1996.
Blunier, T. and Brook, E. J.: Timing of Millennial-Scale climate change in Antarctica and Greenland during the last glacial period, Science, 291, 109–111, 2001.
Blunier, T., Chappellaz, J., Schwander, J., Dällenbach, A., Stauffer, B., Stocker, T. F., Raynaud, D., Jouzel, J., Clausens, H. B., Hammer, C. U., and Johnsen, S. J.: Asynchrony of Antarctic and Greenland climate change during the last glacial period, Nature, 394, 739–743, 1998.
Brook, E. J., Sowers, T., and Orchardo, J.: Rapid variations in atmospheric methane concentration during the past 110000 years, Science, 273, 1087–1091, 1996.
Buizert, C., Martinerie, P., Petrenko, V. V., Severinghaus, J. P., Trudinger, C. M., Witrant, E., Rosen, J. L., Orsi, A. J., Rubino, M., Etheridge, D. M., Steele, L. P., Hogan, C., Laube, J. C., Sturges, W. T., Levchenko, V. A., Smith, A. M., Levin, I., Conway, T. J., Dlugokencky, E. J., Lang, P. M., Kawamura, K., Jenk, T. M., White, J. W. C., Sowers, T., Schwander, J., and Blunier, T.: Gas transport in firn: multiple-tracer characterisation and model intercomparison for NEEM, Northern Greenland, Atmos. Chem. Phys., 12, 4259–4277, https://doi.org/10.5194/acp-12-4259-2012, 2012.
Capron, E., Landais, A., Chappellaz, J., Buiron, D., Fischer, H., Johnsen, S. J., Jouzel, J., Leuenberger, M., Masson-Delmotte, V., and Stocker, T. F.: A global picture of the first abrupt climatic event occurring during the last glacial inception, Geophys. Res. Lett., 39, L15703, https://doi.org/10.1029/2012GL052656, 2012.
Chappellaz, J., Blunier, T., Raynaud, D., Barnola, J.-M., Schwander, J., and Stauffer, B.: Synchronous changes in atmospheric CH4 and Greenland climate between 40 and 8kyr BP, Nature, 366, 443–445, 1993.
Crosson, E. R.: A cavity ring-down analyzer for measuring atmospheric levels of methane, carbon dioxide, and water vapor, Appl. Phys. B, 92, 403–408, 2008.
Dällenbach, A., Blunier, T., Flückiger, J., Stauffer, B., Chappellaz, J., and Raynaud, D.: Changes in the atmospheric CH4 gradient between Greenland and Antarctica during the last glacial and the transition to the Holocene, Geophys. Res. Lett., 27, 1005–1008, 2000.
Dlugokencky, E. J., Masarie, K. A., Lang, P. M., and Tans, P. P.: Continuing decline in the growth rate of the atmospheric methane burden, Nature, 393, 447–450, 1998.
Dlugokencky, E. J., Myers, R. C., Lang, P. M., Masarie, K. A., Crotwell, A. M., Thoning, K. W., Hall, B. D., Elkins, J. W., and Steele, L. P.: Conversion of NOAA atmospheric dry air CH4 mole fractions to a gravimetrically prepared standard scale, J. Geophys. Res.-Atmos., 110, D18306, https://doi.org/10.1029/2005JD006035, 2005.
EPICA community members: One-to-one interhemispheric coupling of polar climate variability during the last glacial, Nature, 444, 195–198, 2006.
Etheridge, D. M., Steele, L. P., Francey, R. J., and Langenfelds, R. L.: Atmospheric methane between 1000 A.D. and present: Evidence of anthropogenic emissions and climatic variability, J. Geophys. Res., 103, 15979–15994, 1998.
Fa\"in, X., Chappellaz, J., Rhodes, R. H., Stowasser, C., Blunier, T., McConnell, J. R., Brook, E. J., Preunkert, S., Legrand, M., Desbois, T., and Romanini, D.: High resolution measurements of carbon monoxide along a late Holocene Greenland ice core: evidence for in-situ production, Clim. Past Discuss., 9, 2817–2857, https://doi.org/10.5194/cpd-9-2817-2013, 2013.
Flückiger, J., Blunier, T., Stauffer, B., Chappellaz, J., Spahni, R., Kawamura, K., Schwander, J., Stocker, T. F., and Dahl-Jensen, D.: N20 and CH4 variations during the last glacial epoch: insight into global processes, Global Biogeochem. Cy., 16, GB1020, https://doi.org/10.1029/2003GB002122, 2004.
Gkinis, V., Popp, T. J., Johnsen, S. J., and Blunier, T.: A continuous stream flash evaporator for the calibration of an IR cavity ring-down spectrometer for the isotopic analysis of water, Isotopes in Environmental and Health Studies, 46, 463–475, 2010.
Grachev, A. M., Brook, E. J., and Severinghaus, J. P.: Abrupt changes in atmospheric methane at the MIS 5b-5a transition, Geophys. Res. Lett., 34, L20703, https://doi.org/10.1029/2007GL029799, 2007.
Grachev, A. M., Brook, E. J., Severinghaus, J. P., and Pisias, N. G.: Relative timing and variability of atmospheric methane and GISP2 oxygen isotopes between 68 and 86 ka, Global Biogeochem. Cy., 23, GB2009, https://doi.org/10.1029/2008GB003330, 2009.
Huber, C., Leuenberger, M., Spahni, R., Flückiger, J., Schwander, J., Stocker, T. F., Johnsen, S., Landais, A., and Jouzel, J.: Isotope calibrated Greenland temperature record over Marine Isotope Stage 3 and its relation to CH4, Earth Planet. Sci. Lett., 243, 504–519, 2006.
Kaufmann, P. R., Federer, U., Hutterli, M. A., Bigler, M., Schupbach, S., Ruth, U., Schmitt, J., and Stocker, T. F.: An Improved Continuous Flow Analysis System for High-Resolution Field Measurements on Ice Cores, Environ. Sci. Technol., 42, 8044–8050, 2008.
Loulergue, L., Schilt, A., Spahni, R., Masson-Delmotte, V., Blunier, T., Lemieux, B., Barnola, J. M., Raynaud, D., Stocker, T. F., and Chappellaz, J.: Orbital and millennial-scale features of atmospheric CH4 over the past 800,000 years, Nature, 453, 383–386, 2008.
Mitchell, L. E., Brook, E. J., Sowers, T., McConnell, J. R., and Taylor, K.: Multidecadal variability of atmospheric methane, 1000–1800 CE, J. Geophys. Res.-Biogeosci., 116, G02007, https://doi.org/10.1029/2010JG001441, 2011.
Nakazawa, T., Machida, T., Tanaka, M., Fujii, Y., Aoki, S., and Watanabe, M.: Antarctic regions in pre-industrial/pre-agricultural era, Geophys. Res.Lett., 20, 943–946, 1993.
North Greenland Ice Core Project members: High resolution record of Northern Hemisphere climate extending into the last interglacial period, Nature, 2805, 1–5, 2004.
Rasmussen, S. O., Abbott, P., Blunier, T., Bourne, A., Brook, E., Buchardt, S. L., Buizert, C., Chappellaz, J., Clausen, H. B., Cook, E., Dahl-Jensen, D., Davies, S., Guillevic, M., Kipfstuhl, S., Laepple, T., Seierstad, I. K., Severinghaus, J. P., Steffensen, J. P., Stowasser, C., Svensson, A., Vallelonga, P., Vinther, B. M., Wilhelms, F., and Winstrup, M.: A first chronology for the NEEM ice core, Clim. Past Discuss., 9, 2967–3013, https://doi.org/10.5194/cpd-9-2967-2013, 2013.
Rhodes, R. H., Faïn, X., Stowasser, C., Blunier, T., Chappellaz, J., McConnell, J. R., Romanini, D., Mitchell, L. E., and Brook, E. J.: Continuous methane measurements from a late Holocene Greenland ice core: Atmospheric and in-situ signals, Earth Planet. Sci. Lett., 368, 9–19, 2013.
Romanini, D., Chenevier, M., Kassi, S., Schmidt, M., Valant, C., Ramonet, M., Lopez, J., and Jost, H. J.: Optical-feedback cavity-enhanced absorption: a compact spectrometer for real-time measurement of atmospheric methane, Appl. Phys., 83, 659–667, 2006.
Rousseau, D. D., Kukla, G., and McManus, J.: What is what in the ice and the ocean?, Quaternary Sci. Rev., 25, 2025–2030, 2006.
Schilt, A., Baumgartner, M., Schwander, J., Buiron, D., Capron, E., Chappellaz, J., Loulergue, L., Schupbach, S., Spahni, R., Fischer, H., and Stocker, T. F.: Atmospheric nitrous oxide during the last 140,000 years, Earth Planet. Sci. Lett., 300, 33–43, 2010.
Schüpbach, S., Federer, U., Kaufmann, P. R., Hutterli, M. A., Buiron, D., Blunier, T., Fischer, H., and Stocker, T. F.: A New Method for High-Resolution Methane Measurements on Polar Ice Cores Using Continuous Flow Analysis, Environ. Sci. Technol., 43, 5371–5376, 2009.
Sowers, T., Brook, E. J., Etheridge, D. M., Blunier, T., Fuchs, A., Leuenberger, M., Chappellaz, J., Barnola, J.-M., Wahlen, M., Deck, B. L., and Weyhenmeyer, C.: An interlaboratory comparison of techniques for extracting and analyzing trapped gases in ice cores, J. Geophys. Res., 102, 26527–26538, 1997.
Stowasser, C., Buizert, C., Gkinis, V., Chappellaz, J., Schüpbach, S., Bigler, M., Fa\"in, X., Sperlich, P., Baumgartner, M., Schilt, A., and Blunier, T.: Continuous measurements of methane mixing ratios from ice cores, Atmos. Meas. Tech., 5, 999–1013, https://doi.org/10.5194/amt-5-999-2012, 2012.
Svensson, A., Bigler, M., Blunier, T., Clausen, H. B., Dahl-Jensen, D., Fischer, H., Fujita, S., Goto-Azuma, K., Johnsen, S. J., Kawamura, K., Kipfstuhl, S., Kohno, M., Parrenin, F., Popp, T., Rasmussen, S. O., Schwander, J., Seierstad, I., Severi, M., Steffensen, J. P., Udisti, R., Uemura, R., Vallelonga, P., Vinther, B. M., Wegner, A., Wilhelms, F., and Winstrup, M.: Direct linking of Greenland and Antarctic ice cores at the Toba eruption (74 ka BP), Clim. Past, 9, 749–766, https://doi.org/10.5194/cp-9-749-2013, 2013.
