Articles | Volume 19, issue 5
https://doi.org/10.5194/cp-19-999-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/cp-19-999-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
22 May 2023
Research article |
| 22 May 2023
| 22 May 2023
Methane, ethane, and propane production in Greenland ice core samples and a first isotopic characterization of excess methane
Climate and Environmental Physics and Oeschger Centre for Climate
Change Research, University of Bern, 3012 Bern, Switzerland
Jochen Schmitt
Climate and Environmental Physics and Oeschger Centre for Climate
Change Research, University of Bern, 3012 Bern, Switzerland
Barbara Seth
Climate and Environmental Physics and Oeschger Centre for Climate
Change Research, University of Bern, 3012 Bern, Switzerland
James E. Lee
Los Alamos National Laboratory, Earth Systems Observation, Los Alamos, NM 87545, USA
Jon S. Edwards
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR 97331, USA
Edward J. Brook
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR 97331, USA
Thomas Blunier
Centre for Ice and Climate, Niels Bohr Institute, University of
Copenhagen, Copenhagen, 2200, Denmark
Hubertus Fischer
Climate and Environmental Physics and Oeschger Centre for Climate
Change Research, University of Bern, 3012 Bern, Switzerland
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François Burgay, Haley Derrod, Tobias Erhardt, Federico Scoto, Delia Segato, Niccolò Maffezzoli, Federico Dallo, Daniele Zannoni, Azzurra Spagnesi, Helle-Astrid Kjær, Hubertus Fischer, Cristiano Varin, Carlo Barbante, and Andrea Spolaor
Clim. Past, 22, 1675–1689, https://doi.org/10.5194/cp-22-1675-2026, https://doi.org/10.5194/cp-22-1675-2026, 2026
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Ice-core measurements from Greenland suggest that atmospheric iron deposition played a smaller role than previously thought in regulating marine productivity in the iron-limited North Pacific. Despite a strong increase in total iron deposition, the fraction of iron more likely to be available to phytoplankton rose only modestly, pointing to sea-ice extent and sedimentary iron remobilization as potentially more important factors during the last glacial transition.
Geunwoo Lee, Tobias Erhardt, Piers Larkman, Chantal Zeppenfeld, Sarah Jackson, Jochen Schmitt, Barbara Delmonte, Giovanni Baccolo, Catherine Ritz, Frank Wilhelms, Dorthe Dahl-Jensen, Kevin Michael Nikolaus, Pascal Bohleber, and Hubertus Fischer
EGUsphere, https://doi.org/10.5194/egusphere-2026-4574, https://doi.org/10.5194/egusphere-2026-4574, 2026
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Deep ice cores preserve records of past climate, but chemical reactions inside the ice can blur these signals over time. To find out how, we studied millions of dust particles in a deep Antarctic ice core. We found that, over long timescales, dust dissolves and reforms into new minerals within tiny pockets of liquid, trapping chemical elements. Warm temperatures speed up this process. Accounting for it helps scientists interpret ancient climate records from deep ice more reliably.
Christian Wirths, Kyung-Sook Yun, Axel Timmermann, Hubertus Fischer, Thomas F. Stocker, and Johannes C. R. Sutter
EGUsphere, https://doi.org/10.5194/egusphere-2026-4275, https://doi.org/10.5194/egusphere-2026-4275, 2026
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Ice drilled from deep inside Antarctica reveals how climate changed over hundreds of thousands of years. However, the ice sheet itself rises and sinks over time, which can distort temperatures read from the ice. Using three computer simulations covering the last two million years, we show that drilling sites rose and sank by up to 240 metres and their summits shifted by up to 120 kilometres, and we estimate how this biases climate records, including potential for the oldest ice.
Alissa Choi, Austin J. Carter, Julia Marks-Peterson, Sarah Shackleton, John A. Higgins, Edward J. Brook, Liam Kirkpatrick, Jacob I. Chalif, and Sarah M. Aarons
EGUsphere, https://doi.org/10.5194/egusphere-2026-2434, https://doi.org/10.5194/egusphere-2026-2434, 2026
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We investigated the particle mass concentration, size distribution, and mineralogy of an ice core drilled from the Allan Hills, Antarctica to assess the preservation of dust records in Blue Ice Areas (BIAs) with complex flow histories. We find potential evidence of alteration including entrainment of basal sediment in the deepest ice, biasing towards interglacial dust concentrations, and chemical weathering. Thus, accurate reconstruction of climate signals in BIAs requires a multiproxy approach.
Lison Soussaintjean, Jochen Schmitt, Joël Savarino, J. Andy Menking, Edward J. Brook, Barbara Seth, Vladimir Lipenkov, Thomas Röckmann, and Hubertus Fischer
Biogeosciences, 23, 3939–3963, https://doi.org/10.5194/bg-23-3939-2026, https://doi.org/10.5194/bg-23-3939-2026, 2026
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Nitrous oxide (N2O) produced in dust-rich Antarctic ice complicates the reconstruction of past atmospheric levels from ice core records. Using isotope analysis, we show that N2O forms from two nitrogen precursors, one being nitrate. For the first time, we demonstrate that the site preference (SP) of N2O reflects the isotopic difference between these precursors, not the production pathway, which challenges the common interpretation of SP.
Abigail Hudak, Asmita Banerjee, Christo Buizert, Edward Brook, Michael Kalk, Lindsey Davidge, Andrew J. Schauer, Eric J. Steig, Noah Brown, Liam Kirkpatrick, John-Morgan Manos, Jacob I. Chalif, Erich Osterberg, Miranda Helena Miranda, Eric Saltzman, Yuzhen Yan, Valens Hishamunda, and John Higgins
EGUsphere, https://doi.org/10.5194/egusphere-2026-2045, https://doi.org/10.5194/egusphere-2026-2045, 2026
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The Allan Hills contains the oldest known ice, extending records millions of years, however, this area along the Transantarctic Mountains margin results in stratigraphically discontinuous ice core records. Here, we investigate high-resolution geochemical records to better constrain biases and stratigraphic complexities, and find these records exhibit reduced variance, some degree of interglacial bias, with varying behaviours across ice cores at the Allan Hills.
Héloïse Guilluy, Émilie Capron, Frédéric Parrenin, Vladimir Lipenkov, Jochen Schmitt, Patricia Martinerie, Zhipeng Wu, Qiuzhen Yin, Anna Maria Klüssendorf, Amaëlle Landais, Barbara Seth, Hubertus Fischer, and Dominique Raynaud
EGUsphere, https://doi.org/10.5194/egusphere-2026-953, https://doi.org/10.5194/egusphere-2026-953, 2026
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Air bubbles in polar ice cores retain information about past climates over hundreds of thousands of years. The total air content (TAC) trapped within these bubbles varies with summer insolation cycles, making it a tool for dating ice cores. We present a multi-site update on TAC, combining new and published data. We confirm that insolation impacts bubble volume in East Antarctica, but surface climate changes can hide the insolation signal in the TAC record, impacting the TAC-derived chronologies.
Marc N. Fiddler, Vaios Moschos, Megan M. McRee, Abu Sayeed Md Shawon, Kyle Gorkowski, James E. Lee, Nevil A. Franco, Katherine B. Benedict, Samir Kattel, Chelia Thompson, Manvendra K. Dubey, and Solomon Bililign
Atmos. Meas. Tech., 19, 307–321, https://doi.org/10.5194/amt-19-307-2026, https://doi.org/10.5194/amt-19-307-2026, 2026
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The study used a photoacoustic spectrometer as a reference instrument to determine the multiple-scattering correction factor Cλ for an AE33 aethalometer at three wavelengths, which we believe is critical for aerosol absorption measurements using aethalometer. This is an important parametrization of Cλ specifically geared towards BB aerosol from African fuels under different aging states, and is of particular importance for future field work in that continent which is at present least studied.
Lisa Ardoin, Catherine Larose, Jean-Louis Tison, Christoph Keuschnig, Vasileios Gkinis, Saïda El Amri, Pierre-Henry Blard, Paul Bierman, Thomas Blunier, Dorthe Dahl-Jensen, Charlotte Maistriau, Jørgen-Peder Steffensen, Thomas Röckmann, and François Fripiat
EGUsphere, https://doi.org/10.5194/egusphere-2025-6204, https://doi.org/10.5194/egusphere-2025-6204, 2026
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We investigated gas dynamics at the ice–bed interface of two Greenland ice cores to assess methane and carbon dioxide behaviour beneath ice sheets. At Camp Century, methane diffuses into the ice and is partly oxidized. At GRIP, methane remains preserved despite oxygen. These contrasts suggest that methane oxidation is controlled by local basal conditions, including ice thickness and substrate availability.
Margaret Harlan, Helle Astrid Kjær, Aylin de Campo, Anders Svensson, Thomas Blunier, Vasileios Gkinis, Sarah Jackson, Christopher Plummer, and Tessa Vance
Earth Syst. Sci. Data, 17, 6255–6271, https://doi.org/10.5194/essd-17-6255-2025, https://doi.org/10.5194/essd-17-6255-2025, 2025
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This paper provides high-resolution chemistry and impurity measurements from the Mount Brown South ice core in East Antarctica, from 873 to 2008 CE. Measurements include sodium, ammonium, hydrogen peroxide, electrolytic conductivity, and insoluble microparticles. Data are provided on three scales: 1 mm and 3 cm averaged depth resolution and decadally averaged. The paper also describes the continuous flow analysis systems used to collect the data and characterizes uncertainties and data quality.
Emily Follansbee, James E. Lee, Mohit L. Dubey, Jonathan F. Dooley, Curtis Shuck, Ken Minschwaner, Andre Santos, Sebastien C. Biraud, and Manvendra K. Dubey
Atmos. Meas. Tech., 18, 4527–4542, https://doi.org/10.5194/amt-18-4527-2025, https://doi.org/10.5194/amt-18-4527-2025, 2025
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This work uses ambient methane and wind measurements to quantify methane emissions from a leaking orphaned oil and gas well using Gaussian plume inversions. Our analysis shows that existing Gaussian plume methods that assume atmospheric stability are prone to large errors. We report a more robust analysis that determines plume dispersion coefficients from our in situ observations. Our technique enables more accurate methane quantification of orphaned oil and gas wells to prioritize plugging.
Mohit L. Dubey, Andre Santos, Andrew B. Moyes, Ken Reichl, James E. Lee, Manvendra K. Dubey, Corentin LeYhuelic, Evan Variano, Emily Follansbee, Fotini K. Chow, and Sébastien C. Biraud
Atmos. Meas. Tech., 18, 2987–3007, https://doi.org/10.5194/amt-18-2987-2025, https://doi.org/10.5194/amt-18-2987-2025, 2025
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Orphaned wells, meaning wells lacking responsible owners, pose a significant and poorly understood environmental challenge. We propose, develop and test a novel method for estimating emissions from orphaned wells using a forced advection sampling technique (FAST) that can overcome many of the limitations in current methods (cost, accuracy, safety). Our results suggest that the FAST method can provide a low-cost alternative to existing methods over a range of leak rates.
Sindhu Vudayagiri, Bo Vinther, Johannes Freitag, Peter L. Langen, and Thomas Blunier
Clim. Past, 21, 517–528, https://doi.org/10.5194/cp-21-517-2025, https://doi.org/10.5194/cp-21-517-2025, 2025
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Air trapped in polar ice during snowfall reflects atmospheric pressure at the time of occlusion, serving as a proxy for elevation. However, melting, firn structure changes, and air pressure variability complicate this relationship. We measured total air content (TAC) in the RECAP ice core from Renland ice cap, eastern Greenland, spanning 121 000 years. Melt layers and short-term TAC variations, whose origins remain unclear, present challenges in interpreting elevation changes.
Julien Westhoff, Johannes Freitag, Anaïs Orsi, Patricia Martinerie, Ilka Weikusat, Michael Dyonisius, Xavier Faïn, Kevin Fourteau, and Thomas Blunier
The Cryosphere, 18, 4379–4397, https://doi.org/10.5194/tc-18-4379-2024, https://doi.org/10.5194/tc-18-4379-2024, 2024
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We study the EastGRIP area, Greenland, in detail with traditional and novel techniques. Due to the compaction of the ice, at a certain depth, atmospheric gases can no longer exchange, and the atmosphere is trapped in air bubbles in the ice. We find this depth by pumping air from a borehole, modeling, and using a new technique based on the optical appearance of the ice. Our results suggest that the close-off depth lies at around 58–61 m depth and more precisely at 58.3 m depth.
Jonathan F. Dooley, Kenneth Minschwaner, Manvendra K. Dubey, Sahar H. El Abbadi, Evan D. Sherwin, Aaron G. Meyer, Emily Follansbee, and James E. Lee
Atmos. Meas. Tech., 17, 5091–5111, https://doi.org/10.5194/amt-17-5091-2024, https://doi.org/10.5194/amt-17-5091-2024, 2024
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Methane is a powerful greenhouse gas originating from both natural and human activities. We describe a new uncrewed aerial system (UAS) designed to measure methane emission rates over a wide range of scales. This system has been used for direct quantification of point sources and distributed emitters over scales of up to 1 km. The system uses simultaneous measurements of methane and ethane to distinguish between different kinds of natural and human-related emission sources.
Susanne Preunkert, Pascal Bohleber, Michel Legrand, Adrien Gilbert, Tobias Erhardt, Roland Purtschert, Lars Zipf, Astrid Waldner, Joseph R. McConnell, and Hubertus Fischer
The Cryosphere, 18, 2177–2194, https://doi.org/10.5194/tc-18-2177-2024, https://doi.org/10.5194/tc-18-2177-2024, 2024
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Ice cores from high-elevation Alpine glaciers are an important tool to reconstruct the past atmosphere. However, since crevasses are common at these glacier sites, rigorous investigations of glaciological conditions upstream of drill sites are needed before interpreting such ice cores. On the basis of three ice cores extracted at Col du Dôme (4250 m a.s.l; French Alps), an overall picture of a dynamic crevasse formation is drawn, which disturbs the depth–age relation of two of the three cores.
Ryan N. Farley, James E. Lee, Laura-Hélèna Rivellini, Alex K. Y. Lee, Rachael Dal Porto, Christopher D. Cappa, Kyle Gorkowski, Abu Sayeed Md Shawon, Katherine B. Benedict, Allison C. Aiken, Manvendra K. Dubey, and Qi Zhang
Atmos. Chem. Phys., 24, 3953–3971, https://doi.org/10.5194/acp-24-3953-2024, https://doi.org/10.5194/acp-24-3953-2024, 2024
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The black carbon aerosol composition and mixing state were characterized using a soot particle aerosol mass spectrometer. Single-particle measurements revealed the major role of atmospheric processing in modulating the black carbon mixing state. A significant fraction of soot particles were internally mixed with oxidized organic aerosol and sulfate, with implications for activation as cloud nuclei.
Tobias Erhardt, Camilla Marie Jensen, Florian Adolphi, Helle Astrid Kjær, Remi Dallmayr, Birthe Twarloh, Melanie Behrens, Motohiro Hirabayashi, Kaori Fukuda, Jun Ogata, François Burgay, Federico Scoto, Ilaria Crotti, Azzurra Spagnesi, Niccoló Maffezzoli, Delia Segato, Chiara Paleari, Florian Mekhaldi, Raimund Muscheler, Sophie Darfeuil, and Hubertus Fischer
Earth Syst. Sci. Data, 15, 5079–5091, https://doi.org/10.5194/essd-15-5079-2023, https://doi.org/10.5194/essd-15-5079-2023, 2023
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The presented paper provides a 3.8 kyr long dataset of aerosol concentrations from the East Greenland Ice coring Project (EGRIP) ice core. The data consists of 1 mm depth-resolution profiles of calcium, sodium, ammonium, nitrate, and electrolytic conductivity as well as decadal averages of these profiles. Alongside the data a detailed description of the measurement setup as well as a discussion of the uncertainties are given.
Xavier Faïn, David M. Etheridge, Kévin Fourteau, Patricia Martinerie, Cathy M. Trudinger, Rachael H. Rhodes, Nathan J. Chellman, Ray L. Langenfelds, Joseph R. McConnell, Mark A. J. Curran, Edward J. Brook, Thomas Blunier, Grégory Teste, Roberto Grilli, Anthony Lemoine, William T. Sturges, Boris Vannière, Johannes Freitag, and Jérôme Chappellaz
Clim. Past, 19, 2287–2311, https://doi.org/10.5194/cp-19-2287-2023, https://doi.org/10.5194/cp-19-2287-2023, 2023
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We report on a 3000-year record of carbon monoxide (CO) levels in the Southern Hemisphere's high latitudes by combining ice core and firn air measurements with modern direct atmospheric samples. Antarctica [CO] remained stable (–835 to 1500 CE), decreased during the Little Ice Age, and peaked around 1985 CE. Such evolution reflects stable biomass burning CO emissions before industrialization, followed by growth from CO anthropogenic sources, which decline after 1985 due to improved combustion.
Jenna A. Epifanio, Edward J. Brook, Christo Buizert, Erin C. Pettit, Jon S. Edwards, John M. Fegyveresi, Todd A. Sowers, Jeffrey P. Severinghaus, and Emma C. Kahle
The Cryosphere, 17, 4837–4851, https://doi.org/10.5194/tc-17-4837-2023, https://doi.org/10.5194/tc-17-4837-2023, 2023
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The total air content (TAC) of polar ice cores has long been considered a potential proxy for past ice sheet elevation. This study presents a high-resolution record of TAC from the South Pole ice core. The record reveals orbital- and millennial-scale variability that cannot be explained by elevation changes. The orbital- and millennial-scale changes are likely a product of firn grain metamorphism near the surface of the ice sheet, due to summer insolation changes or local accumulation changes.
Sune Olander Rasmussen, Dorthe Dahl-Jensen, Hubertus Fischer, Katrin Fuhrer, Steffen Bo Hansen, Margareta Hansson, Christine S. Hvidberg, Ulf Jonsell, Sepp Kipfstuhl, Urs Ruth, Jakob Schwander, Marie-Louise Siggaard-Andersen, Giulia Sinnl, Jørgen Peder Steffensen, Anders M. Svensson, and Bo M. Vinther
Earth Syst. Sci. Data, 15, 3351–3364, https://doi.org/10.5194/essd-15-3351-2023, https://doi.org/10.5194/essd-15-3351-2023, 2023
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Timescales are essential for interpreting palaeoclimate data. The data series presented here were used for annual-layer identification when constructing the timescales named the Greenland Ice-Core Chronology 2005 (GICC05) and the revised version GICC21. Hopefully, these high-resolution data sets will be useful also for other purposes.
Robert Mulvaney, Eric W. Wolff, Mackenzie M. Grieman, Helene H. Hoffmann, Jack D. Humby, Christoph Nehrbass-Ahles, Rachael H. Rhodes, Isobel F. Rowell, Frédéric Parrenin, Loïc Schmidely, Hubertus Fischer, Thomas F. Stocker, Marcus Christl, Raimund Muscheler, Amaelle Landais, and Frédéric Prié
Clim. Past, 19, 851–864, https://doi.org/10.5194/cp-19-851-2023, https://doi.org/10.5194/cp-19-851-2023, 2023
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We present an age scale for a new ice core drilled at Skytrain Ice Rise, an ice rise facing the Ronne Ice Shelf in Antarctica. Various measurements in the ice and air phases are used to match the ice core to other Antarctic cores that have already been dated, and a new age scale is constructed. The 651 m ice core includes ice that is confidently dated to 117 000–126 000 years ago, in the last interglacial. Older ice is found deeper down, but there are flow disturbances in the deeper ice.
Christo Buizert, Sarah Shackleton, Jeffrey P. Severinghaus, William H. G. Roberts, Alan Seltzer, Bernhard Bereiter, Kenji Kawamura, Daniel Baggenstos, Anaïs J. Orsi, Ikumi Oyabu, Benjamin Birner, Jacob D. Morgan, Edward J. Brook, David M. Etheridge, David Thornton, Nancy Bertler, Rebecca L. Pyne, Robert Mulvaney, Ellen Mosley-Thompson, Peter D. Neff, and Vasilii V. Petrenko
Clim. Past, 19, 579–606, https://doi.org/10.5194/cp-19-579-2023, https://doi.org/10.5194/cp-19-579-2023, 2023
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It is unclear how different components of the global atmospheric circulation, such as the El Niño effect, respond to large-scale climate change. We present a new ice core gas proxy, called krypton-86 excess, that reflects past storminess in Antarctica. We present data from 11 ice cores that suggest the new proxy works. We present a reconstruction of changes in West Antarctic storminess over the last 24 000 years and suggest these are caused by north–south movement of the tropical rain belt.
Michael N. Dyonisius, Vasilii V. Petrenko, Andrew M. Smith, Benjamin Hmiel, Peter D. Neff, Bin Yang, Quan Hua, Jochen Schmitt, Sarah A. Shackleton, Christo Buizert, Philip F. Place, James A. Menking, Ross Beaudette, Christina Harth, Michael Kalk, Heidi A. Roop, Bernhard Bereiter, Casey Armanetti, Isaac Vimont, Sylvia Englund Michel, Edward J. Brook, Jeffrey P. Severinghaus, Ray F. Weiss, and Joseph R. McConnell
The Cryosphere, 17, 843–863, https://doi.org/10.5194/tc-17-843-2023, https://doi.org/10.5194/tc-17-843-2023, 2023
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Cosmic rays that enter the atmosphere produce secondary particles which react with surface minerals to produce radioactive nuclides. These nuclides are often used to constrain Earth's surface processes. However, the production rates from muons are not well constrained. We measured 14C in ice with a well-known exposure history to constrain the production rates from muons. 14C production in ice is analogous to quartz, but we obtain different production rates compared to commonly used estimates.
Lars Mächler, Daniel Baggenstos, Florian Krauss, Jochen Schmitt, Bernhard Bereiter, Remo Walther, Christoph Reinhard, Béla Tuzson, Lukas Emmenegger, and Hubertus Fischer
Atmos. Meas. Tech., 16, 355–372, https://doi.org/10.5194/amt-16-355-2023, https://doi.org/10.5194/amt-16-355-2023, 2023
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We present a new method to extract the gases from ice cores and measure their greenhouse gas composition. The ice is sublimated continuously with a near-infrared laser, releasing the gases, which are then analyzed on a laser absorption spectrometer. The main advantage over previous efforts is a low effective resolution of 1–2 cm. This capability is crucial for the analysis of highly thinned ice, as expected from ongoing drilling efforts to extend ice core history further back in time.
Jinhwa Shin, Jinho Ahn, Jai Chowdhry Beeman, Hun-Gyu Lee, Jaemyeong Mango Seo, and Edward J. Brook
Clim. Past, 18, 2063–2075, https://doi.org/10.5194/cp-18-2063-2022, https://doi.org/10.5194/cp-18-2063-2022, 2022
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We present a new and highly resolved atmospheric CO2 record from the Siple Dome ice core, Antarctica, over the early Holocene (11.7–7.4 ka). Atmospheric CO2 decreased by ~10 ppm from 10.9 to 7.3 ka, but the decrease was punctuated by local minima at 11.1, 10.1, 9.1, and 8.3 ka. We found millennial CO2 variability of 2–6 ppm, and the millennial CO2 variations correlate with proxies for solar forcing and local climate in the Southern Ocean, North Atlantic, and eastern equatorial Pacific.
Eric W. Wolff, Hubertus Fischer, Tas van Ommen, and David A. Hodell
Clim. Past, 18, 1563–1577, https://doi.org/10.5194/cp-18-1563-2022, https://doi.org/10.5194/cp-18-1563-2022, 2022
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Projects are underway to drill ice cores in Antarctica reaching 1.5 Myr back in time. Dating such cores will be challenging. One method is to match records from the new core against datasets from existing marine sediment cores. Here we explore the options for doing this and assess how well the ice and marine records match over the existing 800 000-year time period. We are able to recommend a strategy for using marine data to place an age scale on the new ice cores.
Xavier Faïn, Rachael H. Rhodes, Philip Place, Vasilii V. Petrenko, Kévin Fourteau, Nathan Chellman, Edward Crosier, Joseph R. McConnell, Edward J. Brook, Thomas Blunier, Michel Legrand, and Jérôme Chappellaz
Clim. Past, 18, 631–647, https://doi.org/10.5194/cp-18-631-2022, https://doi.org/10.5194/cp-18-631-2022, 2022
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Carbon monoxide (CO) is a regulated pollutant and one of the key components determining the oxidizing capacity of the atmosphere. In this study, we analyzed five ice cores from Greenland at high resolution for CO concentrations by coupling laser spectrometry with continuous melting. By combining these new datasets, we produced an upper-bound estimate of past atmospheric CO abundance since preindustrial times for the Northern Hemisphere high latitudes, covering the period from 1700 to 1957 CE.
Tobias Erhardt, Matthias Bigler, Urs Federer, Gideon Gfeller, Daiana Leuenberger, Olivia Stowasser, Regine Röthlisberger, Simon Schüpbach, Urs Ruth, Birthe Twarloh, Anna Wegner, Kumiko Goto-Azuma, Takayuki Kuramoto, Helle A. Kjær, Paul T. Vallelonga, Marie-Louise Siggaard-Andersen, Margareta E. Hansson, Ailsa K. Benton, Louise G. Fleet, Rob Mulvaney, Elizabeth R. Thomas, Nerilie Abram, Thomas F. Stocker, and Hubertus Fischer
Earth Syst. Sci. Data, 14, 1215–1231, https://doi.org/10.5194/essd-14-1215-2022, https://doi.org/10.5194/essd-14-1215-2022, 2022
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The datasets presented alongside this manuscript contain high-resolution concentration measurements of chemical impurities in deep ice cores, NGRIP and NEEM, from the Greenland ice sheet. The impurities originate from the deposition of aerosols to the surface of the ice sheet and are influenced by source, transport and deposition processes. Together, these records contain detailed, multi-parameter records of past climate variability over the last glacial period.
Jiamei Lin, Anders Svensson, Christine S. Hvidberg, Johannes Lohmann, Steffen Kristiansen, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Sune Olander Rasmussen, Eliza Cook, Helle Astrid Kjær, Bo M. Vinther, Hubertus Fischer, Thomas Stocker, Michael Sigl, Matthias Bigler, Mirko Severi, Rita Traversi, and Robert Mulvaney
Clim. Past, 18, 485–506, https://doi.org/10.5194/cp-18-485-2022, https://doi.org/10.5194/cp-18-485-2022, 2022
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We employ acidity records from Greenland and Antarctic ice cores to estimate the emission strength, frequency and climatic forcing for large volcanic eruptions from the last half of the last glacial period. A total of 25 volcanic eruptions are found to be larger than any eruption in the last 2500 years, and we identify more eruptions than obtained from geological evidence. Towards the end of the glacial period, there is a notable increase in volcanic activity observed for Greenland.
Merve Polat, Jesper Baldtzer Liisberg, Morten Krogsbøll, Thomas Blunier, and Matthew S. Johnson
Atmos. Meas. Tech., 14, 8041–8067, https://doi.org/10.5194/amt-14-8041-2021, https://doi.org/10.5194/amt-14-8041-2021, 2021
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We have designed a process for removing methane from a gas stream so that nitrous oxide can be measured without interference. These are both key long-lived greenhouse gases frequently studied in relation to ice cores, plants, water treatment and so on. However, many researchers are not aware of the problem of methane interference, and in addition there have not been good methods available for solving the problem. Here we present and evaluate such a method.
Sarah Shackleton, James A. Menking, Edward Brook, Christo Buizert, Michael N. Dyonisius, Vasilii V. Petrenko, Daniel Baggenstos, and Jeffrey P. Severinghaus
Clim. Past, 17, 2273–2289, https://doi.org/10.5194/cp-17-2273-2021, https://doi.org/10.5194/cp-17-2273-2021, 2021
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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.
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Short summary
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.
Our ice core measurements show that methane, ethane, and propane concentrations are...
