Articles | Volume 16, issue 6
https://doi.org/10.5194/cp-16-2431-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-16-2431-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
03 Dec 2020
Research article |
| 03 Dec 2020
| 03 Dec 2020
The SP19 chronology for the South Pole Ice Core – Part 2: gas chronology, Δage, and smoothing of atmospheric records
Jenna A. Epifanio
CORRESPONDING AUTHOR
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Edward J. Brook
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Christo Buizert
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Jon S. Edwards
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Todd A. Sowers
The Earth and Environmental Systems Institute, Pennsylvania State
University, University Park, PA, USA
Emma C. Kahle
Department of Earth and Space Science, University of Washington,
Seattle, WA, USA
Jeffrey P. Severinghaus
Scripps Institution of Oceanography, University of California San
Diego, La Jolla, CA, USA
Eric J. Steig
Department of Earth and Space Science, University of Washington,
Seattle, WA, USA
Dominic A. Winski
School of Earth and Climate Sciences, University of Maine, Orono,
ME, USA
Climate Change Institute, University of Maine, Orono, ME, USA
Erich C. Osterberg
Department of Earth Sciences, Dartmouth College, Hanover, NH, USA
Tyler J. Fudge
Department of Earth and Space Science, University of Washington,
Seattle, WA, USA
Murat Aydin
Department of Earth System Science, University of California, Irvine, CA, USA
Ekaterina Hood
Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
Michael Kalk
College of Earth, Ocean, and Atmospheric Sciences, Oregon State
University, Corvallis, OR, USA
Karl J. Kreutz
School of Earth and Climate Sciences, University of Maine, Orono,
ME, USA
Climate Change Institute, University of Maine, Orono, ME, USA
David G. Ferris
Department of Earth Sciences, Dartmouth College, Hanover, NH, USA
Joshua A. Kennedy
Department of Chemistry and Biochemistry, South Dakota State
University, Brookings, SD, USA
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Murat Aydin, Melinda R. Nicewonger, Gregory L. Britten, Dominic Winski, Mary Whelan, John D. Patterson, Erich Osterberg, Christopher F. Lee, Tara Harder, Kyle J. Callahan, David Ferris, and Eric S. Saltzman
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Romilly Harris Stuart, Amaëlle Landais, Laurent Arnaud, Christo Buizert, Emilie Capron, Marie Dumont, Quentin Libois, Robert Mulvaney, Anaïs Orsi, Ghislain Picard, Frédéric Prié, Jeffrey Severinghaus, Barbara Stenni, and Patricia Martinerie
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Vasilii V. Petrenko, Segev BenZvi, Michael Dyonisius, Benjamin Hmiel, Andrew M. Smith, and Christo Buizert
The Cryosphere, 18, 3439–3451, https://doi.org/10.5194/tc-18-3439-2024, https://doi.org/10.5194/tc-18-3439-2024, 2024
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This manuscript presents the concept for a new proxy for past variations in the galactic cosmic ray flux (GCR). Past variations in GCR flux are important to understand for interpretation of records of isotopes produced by cosmic rays; these records are used for reconstructing solar variations and past land ice extent. The proxy involves using measurements of 14CO in ice cores, which should provide an uncomplicated and precise estimate of past GCR flux variations for the past few thousand years.
Benjamin Hmiel, Vasilii V. Petrenko, Christo Buizert, Andrew M. Smith, Michael N. Dyonisius, Philip Place, Bin Yang, Quan Hua, Ross Beaudette, Jeffrey P. Severinghaus, Christina Harth, Ray F. Weiss, Lindsey Davidge, Melisa Diaz, Matthew Pacicco, James A. Menking, Michael Kalk, Xavier Faïn, Alden Adolph, Isaac Vimont, and Lee T. Murray
The Cryosphere, 18, 3363–3382, https://doi.org/10.5194/tc-18-3363-2024, https://doi.org/10.5194/tc-18-3363-2024, 2024
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The main aim of this research is to improve understanding of carbon-14 that is produced by cosmic rays in ice sheets. Measurements of carbon-14 in ice cores can provide a range of useful information (age of ice, past atmospheric chemistry, past cosmic ray intensity). Our results show that almost all (>99 %) of carbon-14 that is produced in the upper layer of ice sheets is rapidly lost to the atmosphere. Our results also provide better estimates of carbon-14 production rates in deeper ice.
Jessica Ng, Jeffrey Severinghaus, Ryan Bay, and Delia Tosi
Clim. Past, 20, 1437–1449, https://doi.org/10.5194/cp-20-1437-2024, https://doi.org/10.5194/cp-20-1437-2024, 2024
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The pattern of Earth’s ice age cycles shifted around a million years ago, becoming more extreme and longer in duration. Multiple projects are underway to obtain an Antarctic ice core that covers this time period, as ice cores contain important clues to why the transition happened. To make sure the ice is old enough at the bottom, we demonstrate how to use new technology to quickly measure dust patterns in the ice and compare them to dust in deep-ocean sediments whose ages are known.
Ian E. McDowell, Kaitlin M. Keegan, S. McKenzie Skiles, Christopher P. Donahue, Erich C. Osterberg, Robert L. Hawley, and Hans-Peter Marshall
The Cryosphere, 18, 1925–1946, https://doi.org/10.5194/tc-18-1925-2024, https://doi.org/10.5194/tc-18-1925-2024, 2024
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Accurate knowledge of firn grain size is crucial for many ice sheet research applications. Unfortunately, collecting detailed measurements of firn grain size is difficult. We demonstrate that scanning firn cores with a near-infrared imager can quickly produce high-resolution maps of both grain size and ice layer distributions. We map grain size and ice layer stratigraphy in 14 firn cores from Greenland and document changes to grain size and ice layer content from the extreme melt summer of 2012.
Tyler J. Fudge, Raphael Sauvage, Linh Vu, Benjamin H. Hills, Mirko Severi, and Edwin D. Waddington
Clim. Past, 20, 297–312, https://doi.org/10.5194/cp-20-297-2024, https://doi.org/10.5194/cp-20-297-2024, 2024
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We use the oldest Antarctic ice core to estimate the rate of diffusion of sulfuric acid. Sulfuric acid is a marker of past volcanic activity and is critical in developing ice core timescales. The rate of diffusion is uncertain and is important to know, both for selecting future ice core locations and interpreting ice core records. We find the effective diffusivity of sulfate is 10 times smaller than previously estimated, indicating that the sulfuric acid signals will persist for longer.
John D. Patterson, Murat Aydin, Andrew M. Crotwell, Gabrielle Pétron, Jeffery P. Severinghaus, Paul B. Krummel, Ray L. Langenfelds, Vasilii V. Petrenko, and Eric S. Saltzman
Clim. Past, 19, 2535–2550, https://doi.org/10.5194/cp-19-2535-2023, https://doi.org/10.5194/cp-19-2535-2023, 2023
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Atmospheric levels of molecular hydrogen (H2) can impact climate and air quality. Constraining past changes to atmospheric H2 is useful for understanding how H2 cycles through the Earth system and predicting the impacts of increasing anthropogenic emissions under the
hydrogen economy. Here, we use the aging air found in the polar snowpack to reconstruct H2 levels over the past 100 years. We find that H2 levels increased by 30 % over Greenland and 60 % over Antarctica during the 20th century.
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.
Gemma K. O'Connor, Paul R. Holland, Eric J. Steig, Pierre Dutrieux, and Gregory J. Hakim
The Cryosphere, 17, 4399–4420, https://doi.org/10.5194/tc-17-4399-2023, https://doi.org/10.5194/tc-17-4399-2023, 2023
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Glaciers in West Antarctica are rapidly melting, but the causes are unknown due to limited observations. A leading hypothesis is that an unusually large wind event in the 1940s initiated the ocean-driven melting. Using proxy reconstructions (e.g., using ice cores) and climate model simulations, we find that wind events similar to the 1940s event are relatively common on millennial timescales, implying that ocean variability or climate trends are also necessary to explain the start of ice loss.
Ling Fang, Theo M. Jenk, Dominic Winski, Karl Kreutz, Hanna L. Brooks, Emma Erwin, Erich Osterberg, Seth Campbell, Cameron Wake, and Margit Schwikowski
The Cryosphere, 17, 4007–4020, https://doi.org/10.5194/tc-17-4007-2023, https://doi.org/10.5194/tc-17-4007-2023, 2023
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Understanding the behavior of ocean–atmosphere teleconnections in the North Pacific during warm intervals can aid in predicting future warming scenarios. However, majority ice core records from Alaska–Yukon region only provide data for the last few centuries. This study introduces a continuous chronology for Denali ice core from Begguya, Alaska, using multiple dating methods. The early-Holocene-origin Denali ice core will facilitate future investigations of hydroclimate in the North Pacific.
Benoit S. Lecavalier, Lev Tarasov, Greg Balco, Perry Spector, Claus-Dieter Hillenbrand, Christo Buizert, Catherine Ritz, Marion Leduc-Leballeur, Robert Mulvaney, Pippa L. Whitehouse, Michael J. Bentley, and Jonathan Bamber
Earth Syst. Sci. Data, 15, 3573–3596, https://doi.org/10.5194/essd-15-3573-2023, https://doi.org/10.5194/essd-15-3573-2023, 2023
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The Antarctic Ice Sheet Evolution constraint database version 2 (AntICE2) consists of a large variety of observations that constrain the evolution of the Antarctic Ice Sheet over the last glacial cycle. This includes observations of past ice sheet extent, past ice thickness, past relative sea level, borehole temperature profiles, and present-day bedrock displacement rates. The database is intended to improve our understanding of past Antarctic changes and for ice sheet model calibrations.
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.
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.
Aaron Chesler, Dominic Winski, Karl Kreutz, Bess Koffman, Erich Osterberg, David Ferris, Zayta Thundercloud, Joseph Mohan, Jihong Cole-Dai, Mark Wells, Michael Handley, Aaron Putnam, Katherine Anderson, and Natalie Harmon
Clim. Past, 19, 477–492, https://doi.org/10.5194/cp-19-477-2023, https://doi.org/10.5194/cp-19-477-2023, 2023
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Ice core microparticle data typically use geometry assumptions to calculate particle mass and flux. We use dynamic particle imaging, a novel technique for ice core dust analyses, combined with traditional laser particle counting and Coulter counter techniques to assess particle shape in the South Pole Ice Core (SPC14) spanning 50–16 ka. Our results suggest that particles are dominantly ellipsoidal in shape and that spherical assumptions overestimate particle mass and flux.
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.
Lindsey Davidge, Eric J. Steig, and Andrew J. Schauer
Atmos. Meas. Tech., 15, 7337–7351, https://doi.org/10.5194/amt-15-7337-2022, https://doi.org/10.5194/amt-15-7337-2022, 2022
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We describe a continuous-flow analysis (CFA) method to measure Δ17O by laser spectroscopy, and we show that centimeter-scale information can be measured reliably in ice cores by this method. We present seasonally resolved Δ17O data from Greenland and demonstrate that the measurement precision is not reduced by the CFA process. Our results encourage the development and use of CFA methods for Δ17O, and they identify calibration strategies as a target for method improvement.
Paul R. Holland, Gemma K. O'Connor, Thomas J. Bracegirdle, Pierre Dutrieux, Kaitlin A. Naughten, Eric J. Steig, David P. Schneider, Adrian Jenkins, and James A. Smith
The Cryosphere, 16, 5085–5105, https://doi.org/10.5194/tc-16-5085-2022, https://doi.org/10.5194/tc-16-5085-2022, 2022
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The Antarctic Ice Sheet is losing ice, causing sea-level rise. However, it is not known whether human-induced climate change has contributed to this ice loss. In this study, we use evidence from climate models and palaeoclimate measurements (e.g. ice cores) to suggest that the ice loss was triggered by natural climate variations but is now sustained by human-forced climate change. This implies that future greenhouse-gas emissions may influence sea-level rise from Antarctica.
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.
Helene M. Hoffmann, Mackenzie M. Grieman, Amy C. F. King, Jenna A. Epifanio, Kaden Martin, Diana Vladimirova, Helena V. Pryer, Emily Doyle, Axel Schmidt, Jack D. Humby, Isobel F. Rowell, Christoph Nehrbass-Ahles, Elizabeth R. Thomas, Robert Mulvaney, and Eric W. Wolff
Clim. Past, 18, 1831–1847, https://doi.org/10.5194/cp-18-1831-2022, https://doi.org/10.5194/cp-18-1831-2022, 2022
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The WACSWAIN project (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) investigates the fate of the West Antarctic Ice Sheet during the last warm period on Earth (115 000–130 000 years before present). Within this framework an ice core was recently drilled at Skytrain Ice Rise. In this study we present a stratigraphic chronology of that ice core based on absolute age markers and annual layer counting for the last 2000 years.
Ingalise Kindstedt, Kristin M. Schild, Dominic Winski, Karl Kreutz, Luke Copland, Seth Campbell, and Erin McConnell
The Cryosphere, 16, 3051–3070, https://doi.org/10.5194/tc-16-3051-2022, https://doi.org/10.5194/tc-16-3051-2022, 2022
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We show that neither the large spatial footprint of the MODIS sensor nor poorly constrained snow emissivity values explain the observed cold offset in MODIS land surface temperatures (LSTs) in the St. Elias. Instead, the offset is most prominent under conditions associated with near-surface temperature inversions. This work represents an advance in the application of MODIS LSTs to glaciated alpine regions, where we often depend solely on remote sensing products for temperature information.
Jacob D. Morgan, Christo Buizert, Tyler J. Fudge, Kenji Kawamura, Jeffrey P. Severinghaus, and Cathy M. Trudinger
The Cryosphere, 16, 2947–2966, https://doi.org/10.5194/tc-16-2947-2022, https://doi.org/10.5194/tc-16-2947-2022, 2022
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The composition of air bubbles in Antarctic ice cores records information about past changes in properties of the snowpack. We find that, near the South Pole, thinner snowpack in the past is often due to steeper surface topography, in which faster winds erode the snow and deposit it in flatter areas. The slope and wind seem to also cause a seasonal bias in the composition of air bubbles in the ice core. These findings will improve interpretation of other ice cores from places with steep slopes.
Bradley R. Markle and Eric J. Steig
Clim. Past, 18, 1321–1368, https://doi.org/10.5194/cp-18-1321-2022, https://doi.org/10.5194/cp-18-1321-2022, 2022
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The geochemistry preserved in polar ice can provide detailed histories of Earth’s climate over millennia. Here we use the stable isotope ratios of ice from many Antarctic ice cores to reconstruct temperature variability of Antarctica and the midlatitude Southern Hemisphere over tens of thousands of years. We improve upon existing methods to estimate temperature from the geochemical measurements and investigate the patterns of climate change in the past.
Giyoon Lee, Jinho Ahn, Hyeontae Ju, Florian Ritterbusch, Ikumi Oyabu, Christo Buizert, Songyi Kim, Jangil Moon, Sambit Ghosh, Kenji Kawamura, Zheng-Tian Lu, Sangbum Hong, Chang Hee Han, Soon Do Hur, Wei Jiang, and Guo-Min Yang
The Cryosphere, 16, 2301–2324, https://doi.org/10.5194/tc-16-2301-2022, https://doi.org/10.5194/tc-16-2301-2022, 2022
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Blue-ice areas (BIAs) have several advantages for reconstructing past climate. However, the complicated ice flow in the area hinders constraining the age. We applied state-of-the-art techniques and found that the ages cover the last deglaciation period. Our study demonstrates that the BIA in northern Victoria Land may help reconstruct the past climate during the termination of the last glacial period.
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.
Ikumi Oyabu, Kenji Kawamura, Tsutomu Uchida, Shuji Fujita, Kyotaro Kitamura, Motohiro Hirabayashi, Shuji Aoki, Shinji Morimoto, Takakiyo Nakazawa, Jeffrey P. Severinghaus, and Jacob D. Morgan
The Cryosphere, 15, 5529–5555, https://doi.org/10.5194/tc-15-5529-2021, https://doi.org/10.5194/tc-15-5529-2021, 2021
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We present O2/N2 and Ar/N2 records from the Dome Fuji ice core through the bubbly ice, bubble–clathrate transition, and clathrate ice zones without gas-loss fractionation. The insolation signal is preserved through the clathrate formation. The relationship between Ar/Ν2 and Ο2/Ν2 suggests that the fractionation for the bubble–clathrate transition is mass independent, while the bubble close-off process involves a combination of mass-independent and mass-dependent fractionation for O2 and Ar.
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.
Yuzhen Yan, Nicole E. Spaulding, Michael L. Bender, Edward J. Brook, John A. Higgins, Andrei V. Kurbatov, and Paul A. Mayewski
Clim. Past, 17, 1841–1855, https://doi.org/10.5194/cp-17-1841-2021, https://doi.org/10.5194/cp-17-1841-2021, 2021
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Here we reconstruct the rate of snow accumulation during the Last Interglacial period in an East Antarctic ice core located near the present-day northern edge of the Ross Ice Shelf. We find an order-of-magnitude increase in the accumulation rate during the peak warming in the Last Interglacial. This large increase in mass accumulation is compatible with less ice cover in the Ross Sea, perhaps created by a partly collapsed West Antarctic Ice Sheet, whose stability in a warming world is uncertain.
Benjamin Birner, William Paplawsky, Jeffrey Severinghaus, and Ralph F. Keeling
Atmos. Meas. Tech., 14, 2515–2527, https://doi.org/10.5194/amt-14-2515-2021, https://doi.org/10.5194/amt-14-2515-2021, 2021
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The atmospheric helium-to-nitrogen ratio is a promising indicator for circulation changes in the upper atmosphere and fossil fuel burning by humans. We present a very precise analysis method to determine changes in the helium-to-nitrogen ratio of air samples. The method relies on stabilizing the gas flow to a mass spectrometer and continuous removal of reactive gases. These advances enable new insights and monitoring possibilities for anthropogenic and natural processes.
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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Air in polar ice cores provides information on past atmosphere and climate. We present a new method for simultaneously measuring eight gases (CH4, N2O and CO2 concentrations; isotopic ratios of N2 and O2; elemental ratios between N2, O2 and Ar; and total air content) from single ice-core samples with high precision.
Benjamin Birner, Martyn P. Chipperfield, Eric J. Morgan, Britton B. Stephens, Marianna Linz, Wuhu Feng, Chris Wilson, Jonathan D. Bent, Steven C. Wofsy, Jeffrey Severinghaus, and Ralph F. Keeling
Atmos. Chem. Phys., 20, 12391–12408, https://doi.org/10.5194/acp-20-12391-2020, https://doi.org/10.5194/acp-20-12391-2020, 2020
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With new high-precision observations from nine aircraft campaigns and 3-D chemical transport modeling, we show that the argon-to-nitrogen ratio (Ar / N2) in the lowermost stratosphere provides a useful constraint on the “age of air” (the time elapsed since entry of an air parcel into the stratosphere). Therefore, Ar / N2 in combination with traditional age-of-air indicators, such as CO2 and N2O, could provide new insights into atmospheric mixing and transport.
C. Max Stevens, Vincent Verjans, Jessica M. D. Lundin, Emma C. Kahle, Annika N. Horlings, Brita I. Horlings, and Edwin D. Waddington
Geosci. Model Dev., 13, 4355–4377, https://doi.org/10.5194/gmd-13-4355-2020, https://doi.org/10.5194/gmd-13-4355-2020, 2020
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Understanding processes in snow (firn), including compaction and airflow, is important for calculating how much mass the ice sheets are losing and for interpreting climate records from ice cores. We have developed the open-source Community Firn Model to simulate these processes. We used it to compare 13 different firn compaction equations and found that they do not agree within 10 %. We also show that including firn compaction in a firn-air model improves the match with data from ice cores.
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.
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.
Jessica A. Badgeley, Eric J. Steig, Gregory J. Hakim, and Tyler J. Fudge
Clim. Past, 16, 1325–1346, https://doi.org/10.5194/cp-16-1325-2020, https://doi.org/10.5194/cp-16-1325-2020, 2020
Tyler J. Fudge, David A. Lilien, Michelle Koutnik, Howard Conway, C. Max Stevens, Edwin D. Waddington, Eric J. Steig, Andrew J. Schauer, and Nicholas Holschuh
Clim. Past, 16, 819–832, https://doi.org/10.5194/cp-16-819-2020, https://doi.org/10.5194/cp-16-819-2020, 2020
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A 1750 m ice core at the South Pole was recently drilled. The oldest ice is ~55 000 years old. Since ice at the South Pole flows at 10 m per year, the ice in the core originated upstream, where the climate is different. We made measurements of the ice flow, snow accumulation, and temperature upstream. We determined the ice came from ~150 km away near the Titan Dome where the accumulation rate was similar but the temperature was colder. Our measurements improve the interpretation of the ice core.
Gabriel Lewis, Erich Osterberg, Robert Hawley, Hans Peter Marshall, Tate Meehan, Karina Graeter, Forrest McCarthy, Thomas Overly, Zayta Thundercloud, and David Ferris
The Cryosphere, 13, 2797–2815, https://doi.org/10.5194/tc-13-2797-2019, https://doi.org/10.5194/tc-13-2797-2019, 2019
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We present accumulation records from sixteen 22–32 m long firn cores and 4436 km of ground-penetrating radar, covering the past 20–60 years of accumulation, collected across the western Greenland Ice Sheet percolation zone. Trends from both radar and firn cores, as well as commonly used regional climate models, show decreasing accumulation over the 1996–2016 period.
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.
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.
Youngjoon Jang, Sang Bum Hong, Christo Buizert, Hun-Gyu Lee, Sang-Young Han, Ji-Woong Yang, Yoshinori Iizuka, Akira Hori, Yeongcheol Han, Seong Joon Jun, Pieter Tans, Taejin Choi, Seong-Joong Kim, Soon Do Hur, and Jinho Ahn
The Cryosphere, 13, 2407–2419, https://doi.org/10.5194/tc-13-2407-2019, https://doi.org/10.5194/tc-13-2407-2019, 2019
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We can learn how human activity altered atmospheric air from the interstitial air in the porous snow layer (firn) on top of glaciers. However, old firn air (> 55 years) was observed only at sites where surface temperatures and snow accumulation rates are very low, such as the South Pole. In this study, we report an unusually old firn air with CO2 age of 93 years from Styx Glacier, near the Ross Sea coast in Antarctica. We hypothesize that the large snow density variations increase firn air ages.
Jens Mühle, Cathy M. Trudinger, Luke M. Western, Matthew Rigby, Martin K. Vollmer, Sunyoung Park, Alistair J. Manning, Daniel Say, Anita Ganesan, L. Paul Steele, Diane J. Ivy, Tim Arnold, Shanlan Li, Andreas Stohl, Christina M. Harth, Peter K. Salameh, Archie McCulloch, Simon O'Doherty, Mi-Kyung Park, Chun Ok Jo, Dickon Young, Kieran M. Stanley, Paul B. Krummel, Blagoj Mitrevski, Ove Hermansen, Chris Lunder, Nikolaos Evangeliou, Bo Yao, Jooil Kim, Benjamin Hmiel, Christo Buizert, Vasilii V. Petrenko, Jgor Arduini, Michela Maione, David M. Etheridge, Eleni Michalopoulou, Mike Czerniak, Jeffrey P. Severinghaus, Stefan Reimann, Peter G. Simmonds, Paul J. Fraser, Ronald G. Prinn, and Ray F. Weiss
Atmos. Chem. Phys., 19, 10335–10359, https://doi.org/10.5194/acp-19-10335-2019, https://doi.org/10.5194/acp-19-10335-2019, 2019
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We discuss atmospheric concentrations and emissions of the strong greenhouse gas perfluorocyclobutane. A large fraction of recent emissions stem from China, India, and Russia, probably as a by-product from the production of fluoropolymers and fluorochemicals. Most historic emissions likely stem from developed countries. Total emissions are higher than what is being reported. Clearly, more measurements and better reporting are needed to understand emissions of this and other greenhouse gases.
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.
Robert Tardif, Gregory J. Hakim, Walter A. Perkins, Kaleb A. Horlick, Michael P. Erb, Julien Emile-Geay, David M. Anderson, Eric J. Steig, and David Noone
Clim. Past, 15, 1251–1273, https://doi.org/10.5194/cp-15-1251-2019, https://doi.org/10.5194/cp-15-1251-2019, 2019
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An updated Last Millennium Reanalysis is presented, using an expanded multi-proxy database, and proxy models representing the seasonal characteristics of proxy records, in addition to the dual sensitivity to temperature and moisture of tree-ring-width chronologies. We show enhanced skill in spatial reconstructions of key climate variables in the updated reanalysis, compared to an earlier version, resulting from the combined influences of the enhanced proxy network and improved proxy modeling.
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.
William Kochtitzky, Dominic Winski, Erin McConnel, Karl Kreutz, Seth Campbell, Ellyn M. Enderlin, Luke Copland, Scott Williamson, Brittany Main, Christine Dow, and Hester Jiskoot
The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-72, https://doi.org/10.5194/tc-2019-72, 2019
Manuscript not accepted for further review
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Donjek Glacier has experienced eight instability events since 1935. Here we use a suite of weather and satellite data to understand the impacts of climate on instability events. We find that while there has been a consistent amount of snow fall between instability events, the relationship between the two is unclear as they are both very consistent on decade timescales. We show that we need further glacier observations to understand why these glaciers become unstable.
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.
Mackenzie M. Grieman, Murat Aydin, Joseph R. McConnell, and Eric S. Saltzman
Clim. Past, 14, 1625–1637, https://doi.org/10.5194/cp-14-1625-2018, https://doi.org/10.5194/cp-14-1625-2018, 2018
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Vanillic acid is reported in the Tunu ice core from northeastern Greenland. It is an aerosol-borne acid produced by biomass burning. North American boreal forests are likely the source regions of the vanillic acid deposited at the ice core site. Vanillic acid levels were elevated during warm climate periods and lower during cooler climate periods. There is a positive correlation between the vanillic acid ice core record and ammonium and black carbon in the NEEM ice core from northern Greenland.
Frazer D. W. Christie, Robert G. Bingham, Noel Gourmelen, Eric J. Steig, Rosie R. Bisset, Hamish D. Pritchard, Kate Snow, and Simon F. B. Tett
The Cryosphere, 12, 2461–2479, https://doi.org/10.5194/tc-12-2461-2018, https://doi.org/10.5194/tc-12-2461-2018, 2018
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With a focus on the hitherto little-studied Marie Byrd Land coastline linking Antarctica's more comprehensively studied Amundsen and Ross Sea Embayments, this paper uses both satellite remote sensing (Landsat, ASTER, ICESat, and CryoSat2) and climate and ocean records (i.e. ERA-Interim, Met Office EN4 data) to examine links between ice recession, inter-decadal atmosphere-ocean forcing and other influences acting upon the Pacific-facing coastline of West Antarctica.
Benjamin Birner, Christo Buizert, Till J. W. Wagner, and Jeffrey P. Severinghaus
The Cryosphere, 12, 2021–2037, https://doi.org/10.5194/tc-12-2021-2018, https://doi.org/10.5194/tc-12-2021-2018, 2018
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Ancient air enclosed in bubbles of the Antarctic ice sheet is a key source of information about the Earth's past climate. However, a range of physical processes in the snow layer atop an ice sheet may change the trapped air's chemical composition before it is occluded in the ice. We developed the first detailed 2-D computer simulation of these processes and found a new method to improve the reconstruction of past climate from air in ice cores bubbles.
Mackenzie M. Grieman, Murat Aydin, Elisabeth Isaksson, Margit Schwikowski, and Eric S. Saltzman
Clim. Past, 14, 637–651, https://doi.org/10.5194/cp-14-637-2018, https://doi.org/10.5194/cp-14-637-2018, 2018
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This study presents organic acid levels in an ice core from Svalbard over the past 800 years. These acids are produced from wildfire emissions and transported as aerosol. Organic acid levels are high early in the record and decline until the 20th century. Siberia and Europe are likely the primary source regions of the fire emissions. The data are similar to those from a Siberian ice core prior to 1400 CE. The timing of the divergence after 1400 CE is similar to a shift in North Atlantic climate.
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.
Barbara Stenni, Mark A. J. Curran, Nerilie J. Abram, Anais Orsi, Sentia Goursaud, Valerie Masson-Delmotte, Raphael Neukom, Hugues Goosse, Dmitry Divine, Tas van Ommen, Eric J. Steig, Daniel A. Dixon, Elizabeth R. Thomas, Nancy A. N. Bertler, Elisabeth Isaksson, Alexey Ekaykin, Martin Werner, and Massimo Frezzotti
Clim. Past, 13, 1609–1634, https://doi.org/10.5194/cp-13-1609-2017, https://doi.org/10.5194/cp-13-1609-2017, 2017
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Within PAGES Antarctica2k, we build an enlarged database of ice core water stable isotope records. We produce isotopic composites and temperature reconstructions since 0 CE for seven distinct Antarctic regions. We find a significant cooling trend from 0 to 1900 CE across all regions. Since 1900 CE, significant warming trends are identified for three regions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of last-2000-year natural variability.
Elizabeth R. Thomas, J. Melchior van Wessem, Jason Roberts, Elisabeth Isaksson, Elisabeth Schlosser, Tyler J. Fudge, Paul Vallelonga, Brooke Medley, Jan Lenaerts, Nancy Bertler, Michiel R. van den Broeke, Daniel A. Dixon, Massimo Frezzotti, Barbara Stenni, Mark Curran, and Alexey A. Ekaykin
Clim. Past, 13, 1491–1513, https://doi.org/10.5194/cp-13-1491-2017, https://doi.org/10.5194/cp-13-1491-2017, 2017
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Regional Antarctic snow accumulation derived from 79 ice core records is evaluated as part of the PAGES Antarctica 2k working group. Our results show that surface mass balance for the total Antarctic ice sheet has increased at a rate of 7 ± 0.13 Gt dec-1 since 1800 AD, representing a net reduction in sea level of ~ 0.02 mm dec-1 since 1800 and ~ 0.04 mm dec-1 since 1900 AD. The largest contribution is from the Antarctic Peninsula.
Alan M. Seltzer, Christo Buizert, Daniel Baggenstos, Edward J. Brook, Jinho Ahn, Ji-Woong Yang, and Jeffrey P. Severinghaus
Clim. Past, 13, 1323–1338, https://doi.org/10.5194/cp-13-1323-2017, https://doi.org/10.5194/cp-13-1323-2017, 2017
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To explore whether the oxygen-18 to oxygen-16 ratio of atmospheric O2 is sensitive to the position of the tropical rain belts, we (1) present a record of ice core bubble oxygen isotope measurements from two Antarctic ice cores, and (2) examine the sensitivity of oxygen isotopes in precipitation, weighted by photosynthesis, to the location of oxygen production over the modern-day seasonal cycle. We find a strong modern relationship and discuss implications for past shifts in tropical rainfall.
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.
Daniel Baggenstos, Thomas K. Bauska, Jeffrey P. Severinghaus, James E. Lee, Hinrich Schaefer, Christo Buizert, Edward J. Brook, Sarah Shackleton, and Vasilii V. Petrenko
Clim. Past, 13, 943–958, https://doi.org/10.5194/cp-13-943-2017, https://doi.org/10.5194/cp-13-943-2017, 2017
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We present measurements of the gas composition in trapped air bubbles in ice samples taken from Taylor Glacier, Antarctica. We can show that ice from the entire last glacial cycle (125 000 years ago to the present) is exposed at the surface of this glacier and that the atmospheric record contained in the air bubbles is well preserved. Taylor Glacier therefore provides an easily accessible archive of ancient ice that allows for studies of trace components that require large ice volumes.
Dennis L. Nielson, Chris Delahunty, John W. Goodge, and Jeffery P. Severinghaus
Sci. Dril., 22, 29–33, https://doi.org/10.5194/sd-22-29-2017, https://doi.org/10.5194/sd-22-29-2017, 2017
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The North American Testing (NAT) was designed to test critical functions of a Rapid Access Ice Drill (RAID) at a site in northern Utah. The RAID was designed to rapidly drill in Antarctica through over 2500 m of ice and then take a core sample of the bedrock. The system has many innovative features that required field testing before the system was shipped to Antarcitca. The NAT facility consisted of a borehole where we froze a column of ice to test drilling and fluid circulation functions.
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).
Mackenzie M. Grieman, Murat Aydin, Diedrich Fritzsche, Joseph R. McConnell, Thomas Opel, Michael Sigl, and Eric S. Saltzman
Clim. Past, 13, 395–410, https://doi.org/10.5194/cp-13-395-2017, https://doi.org/10.5194/cp-13-395-2017, 2017
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Wildfires impact ecosystems, climate, and atmospheric chemistry. Records that predate instrumental records and industrialization are needed to study the climatic controls on biomass burning. In this study, we analyzed organic chemicals produced from burning of plant matter that were preserved in an ice core from the Eurasian Arctic. These chemicals are elevated during three periods that have similar timing to climate variability. This is the first millennial-scale record of these chemicals.
Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, and Jason Box
The Cryosphere, 11, 773–788, https://doi.org/10.5194/tc-11-773-2017, https://doi.org/10.5194/tc-11-773-2017, 2017
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We analyze 25 flight lines from NASA's Operation IceBridge Accumulation Radar totaling to determine snow accumulation throughout the dry snow and percolation zone of the Greenland Ice Sheet. Our results indicate that regional differences between IceBridge and model accumulation are large enough to significantly alter the Greenland Ice Sheet surface mass balance, with implications for future global sea-level rise.
Tyler R. Jones, James W. C. White, Eric J. Steig, Bruce H. Vaughn, Valerie Morris, Vasileios Gkinis, Bradley R. Markle, and Spruce W. Schoenemann
Atmos. Meas. Tech., 10, 617–632, https://doi.org/10.5194/amt-10-617-2017, https://doi.org/10.5194/amt-10-617-2017, 2017
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New measurement systems have been developed that continuously melt ice core samples, in contrast to other methods that analyze a single sample at a time. These newer systems are capable of reducing analysis time by many years and improving data set resolution. In this study, we introduce improved methodologies that optimize the speed, accuracy, and precision of a water isotope continuous-flow system. The presented system will be used for Antarctic and Greenland ice core projects.
Christo Buizert and Jeffrey P. Severinghaus
The Cryosphere, 10, 2099–2111, https://doi.org/10.5194/tc-10-2099-2016, https://doi.org/10.5194/tc-10-2099-2016, 2016
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The upper 50–100 m of the world's ice sheets consists of the firn layer, a porous layer of snow that is slowly compacted by overlying snow. Understanding air movement inside the firn is critical for ice core climate reconstructions. Buizert and Severinghaus identify and describe a new mechanism of firn air movement. High- and low-pressure systems force air movement in the firn that drives strong mixing, called dispersion. Dispersion is the main mechanism for air mixing in the deep firn.
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.
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.
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
L. Geng, J. Cole-Dai, B. Alexander, J. Erbland, J. Savarino, A. J. Schauer, E. J. Steig, P. Lin, Q. Fu, and M. C. Zatko
Atmos. Chem. Phys., 14, 13361–13376, https://doi.org/10.5194/acp-14-13361-2014, https://doi.org/10.5194/acp-14-13361-2014, 2014
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Examinations on snowpit and firn core results from Summit, Greenland suggest that there are two mechanisms leading to the observed double nitrate peaks in some years in the industrial era: 1) long-rang transport of nitrate and 2) enhanced local photochemical production of nitrate. Both of these mechanisms are related to pollution transport, as the additional nitrate from either direct transport or enhanced local photochemistry requires enhanced nitrogen sources from anthropogenic emissions.
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
E. J. Steig, V. Gkinis, A. J. Schauer, S. W. Schoenemann, K. Samek, J. Hoffnagle, K. J. Dennis, and S. M. Tan
Atmos. Meas. Tech., 7, 2421–2435, https://doi.org/10.5194/amt-7-2421-2014, https://doi.org/10.5194/amt-7-2421-2014, 2014
B. Medley, I. Joughin, B. E. Smith, S. B. Das, E. J. Steig, H. Conway, S. Gogineni, C. Lewis, A. S. Criscitiello, J. R. McConnell, M. R. van den Broeke, J. T. M. Lenaerts, D. H. Bromwich, J. P. Nicolas, and C. Leuschen
The Cryosphere, 8, 1375–1392, https://doi.org/10.5194/tc-8-1375-2014, https://doi.org/10.5194/tc-8-1375-2014, 2014
T. J. Fudge, E. D. Waddington, H. Conway, J. M. D. Lundin, and K. Taylor
Clim. Past, 10, 1195–1209, https://doi.org/10.5194/cp-10-1195-2014, https://doi.org/10.5194/cp-10-1195-2014, 2014
B. G. Koffman, K. J. Kreutz, D. J. Breton, E. J. Kane, D. A. Winski, S. D. Birkel, A. V. Kurbatov, and M. J. Handley
Clim. Past, 10, 1125–1144, https://doi.org/10.5194/cp-10-1125-2014, https://doi.org/10.5194/cp-10-1125-2014, 2014
E. D. Sofen, B. Alexander, E. J. Steig, M. H. Thiemens, S. A. Kunasek, H. M. Amos, A. J. Schauer, M. G. Hastings, J. Bautista, T. L. Jackson, L. E. Vogel, J. R. McConnell, D. R. Pasteris, and E. S. Saltzman
Atmos. Chem. Phys., 14, 5749–5769, https://doi.org/10.5194/acp-14-5749-2014, https://doi.org/10.5194/acp-14-5749-2014, 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
B. D. Hall, A. Engel, J. Mühle, J. W. Elkins, F. Artuso, E. Atlas, M. Aydin, D. Blake, E.-G. Brunke, S. Chiavarini, P. J. Fraser, J. Happell, P. B. Krummel, I. Levin, M. Loewenstein, M. Maione, S. A. Montzka, S. O'Doherty, S. Reimann, G. Rhoderick, E. S. Saltzman, H. E. Scheel, L. P. Steele, M. K. Vollmer, R. F. Weiss, D. Worthy, and Y. Yokouchi
Atmos. Meas. Tech., 7, 469–490, https://doi.org/10.5194/amt-7-469-2014, https://doi.org/10.5194/amt-7-469-2014, 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
K. Kawamura, J. P. Severinghaus, M. R. Albert, Z. R. Courville, M. A. Fahnestock, T. Scambos, E. Shields, and C. A. Shuman
Atmos. Chem. Phys., 13, 11141–11155, https://doi.org/10.5194/acp-13-11141-2013, https://doi.org/10.5194/acp-13-11141-2013, 2013
J. Chappellaz, C. Stowasser, T. Blunier, D. Baslev-Clausen, E. J. Brook, R. Dallmayr, X. Faïn, J. E. Lee, L. E. Mitchell, O. Pascual, D. Romanini, J. Rosen, and S. Schüpbach
Clim. Past, 9, 2579–2593, https://doi.org/10.5194/cp-9-2579-2013, https://doi.org/10.5194/cp-9-2579-2013, 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
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
Related subject area
Subject: Proxy Use-Development-Validation | Archive: Ice Cores | Timescale: Millenial/D-O
Estimating biases during detection of leads and lags between climate elements across Dansgaard–Oeschger events
Continuous synchronization of the Greenland ice-core and U–Th timescales using probabilistic inversion
Statistical precursor signals for Dansgaard–Oeschger cooling transitions
Synchronizing ice-core and U ∕ Th timescales in the Last Glacial Maximum using Hulu Cave 14C and new 10Be measurements from Greenland and Antarctica
Assessing the statistical uniqueness of the Younger Dryas: a robust multivariate analysis
Decadal-scale progression of the onset of Dansgaard–Oeschger warming events
A complete representation of uncertainties in layer-counted paleoclimatic archives
Climatic and insolation control on the high-resolution total air content in the NGRIP ice core
Variability of sulfate signal in ice core records based on five replicate cores
Simulating ice core 10Be on the glacial–interglacial timescale
Evidence for a three-phase sequence during Heinrich Stadial 4 using a multiproxy approach based on Greenland ice core records
Dansgaard–Oeschger events: bifurcation points in the climate system
An automated approach for annual layer counting in ice cores
Duration of Greenland Stadial 22 and ice-gas Δage from counting of annual layers in Greenland NGRIP ice core
Past surface temperatures at the NorthGRIP drill site from the difference in firn diffusion of water isotopes
Bayesian analysis of rapid climate change during the last glacial using Greenland δ18O data
John Slattery, Louise C. Sime, Francesco Muschitiello, and Keno Riechers
Clim. Past, 20, 2431–2454, https://doi.org/10.5194/cp-20-2431-2024, https://doi.org/10.5194/cp-20-2431-2024, 2024
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Dansgaard–Oeschger events are a series of abrupt past climate change events during which the atmosphere, sea ice, and ocean in the North Atlantic underwent rapid changes. One current topic of interest is the order in which these different changes occurred, which remains unknown. In this work, we find that the current best method used to investigate this topic is subject to substantial bias. This implies that it is not possible to reliably determine the order of the different changes.
Francesco Muschitiello and Marco Antonio Aquino-Lopez
Clim. Past, 20, 1415–1435, https://doi.org/10.5194/cp-20-1415-2024, https://doi.org/10.5194/cp-20-1415-2024, 2024
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The first continuously measured transfer functions that quantify the age difference between the Greenland ice-core chronology 2005 (GICC05) and the U–Th timescale are presented. The transfer functions were generated using a novel probabilistic algorithm for the synchronization of proxy signals. The results greatly improve the accuracy and precision of previous synchronization estimates and reveal that the annual-layer counting error of GICC05 is less systematic than previously assumed.
Takahito Mitsui and Niklas Boers
Clim. Past, 20, 683–699, https://doi.org/10.5194/cp-20-683-2024, https://doi.org/10.5194/cp-20-683-2024, 2024
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In general, the variance and short-lag autocorrelations of the fluctuations increase in a system approaching a critical transition. Using these indicators, we identify statistical precursor signals for the Dansgaard–Oeschger cooling events recorded in two climatic proxies of three Greenland ice core records. We then provide a dynamical systems theory that bridges the gap between observing statistical precursor signals and the physical precursor signs empirically known in paleoclimate research.
Giulia Sinnl, Florian Adolphi, Marcus Christl, Kees C. Welten, Thomas Woodruff, Marc Caffee, Anders Svensson, Raimund Muscheler, and Sune Olander Rasmussen
Clim. Past, 19, 1153–1175, https://doi.org/10.5194/cp-19-1153-2023, https://doi.org/10.5194/cp-19-1153-2023, 2023
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The record of past climate is preserved by several archives from different regions, such as ice cores from Greenland or Antarctica or speleothems from caves such as the Hulu Cave in China. In this study, these archives are aligned by taking advantage of the globally synchronous production of cosmogenic radionuclides. This produces a new perspective on the global climate in the period between 20 000 and 25 000 years ago.
Henry Nye and Alan Condron
Clim. Past, 17, 1409–1421, https://doi.org/10.5194/cp-17-1409-2021, https://doi.org/10.5194/cp-17-1409-2021, 2021
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This paper analyzes the uniqueness of a paleoclimate event entitled the Bølling–Allerød Younger Dryas (BA/YD) through a statistical lens in order to better understand its relation to other events similar to it. Furthermore, we implement a novel statistical method entitled PCOut in order to measure the BA/YD's various elements of uniqueness in existing paleoclimate records. We suggest future use of this method for paleoclimate research that aims to assess uniqueness across multiple criteria.
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.
Niklas Boers, Bedartha Goswami, and Michael Ghil
Clim. Past, 13, 1169–1180, https://doi.org/10.5194/cp-13-1169-2017, https://doi.org/10.5194/cp-13-1169-2017, 2017
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We introduce a Bayesian framework to represent layer-counted proxy records as probability distributions on error-free time axes, accounting for both proxy and dating errors. Our method is applied to NGRIP δ18O data, revealing that the cumulative dating errors lead to substantial uncertainties for the older parts of the record. Applying our method to the widely used radiocarbon comparison curve derived from varved sediments of Lake Suigetsu provides the complete uncertainties of this curve.
Olivier Eicher, Matthias Baumgartner, Adrian Schilt, Jochen Schmitt, Jakob Schwander, Thomas F. Stocker, and Hubertus Fischer
Clim. Past, 12, 1979–1993, https://doi.org/10.5194/cp-12-1979-2016, https://doi.org/10.5194/cp-12-1979-2016, 2016
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A new high-resolution total air content record over the NGRIP ice core, spanning 0.3–120 kyr is presented. In agreement with Antarctic ice cores, we find a strong local insolation signature but also 3–5 % decreases in total air content as a local response to Dansgaard–Oeschger events, which can only partly be explained by changes in surface pressure and temperature. Accordingly, a dynamic response of firnification to rapid climate changes on the Greenland ice sheet must have occurred.
E. Gautier, J. Savarino, J. Erbland, A. Lanciki, and P. Possenti
Clim. Past, 12, 103–113, https://doi.org/10.5194/cp-12-103-2016, https://doi.org/10.5194/cp-12-103-2016, 2016
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We evaluate the local-scale variability of a sulfate profile at a low-accumulation site (Dome C, Antarctica) to assess the representativeness of one ice core for volcanic reconstructions. Peak statistical occurrence, depth and flux variability are evaluated from five cores. Due to local-scale variability, 64 volcanic peaks can be identified by a five-cores analysis, while only half of them can be assessed from two cores. Using five cores, the uncertainty of the mean flux is reduced to 29 %.
C. Elsässer, D. Wagenbach, I. Levin, A. Stanzick, M. Christl, A. Wallner, S. Kipfstuhl, I. K. Seierstad, H. Wershofen, and J. Dibb
Clim. Past, 11, 115–133, https://doi.org/10.5194/cp-11-115-2015, https://doi.org/10.5194/cp-11-115-2015, 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
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Short summary
A new ice core drilled at the South Pole provides a 54 000-year paleo-environmental record including the composition of the past atmosphere. This paper describes the gas chronology for the South Pole ice core, based on a high-resolution methane record. The new gas chronology, in combination with the existing ice age scale from Winski et al. (2019), allows a model-independent reconstruction of the delta age record.
A new ice core drilled at the South Pole provides a 54 000-year paleo-environmental record...
