Articles | Volume 18, issue 21
https://doi.org/10.5194/gmd-18-8203-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-18-8203-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Model description paper
| 
05 Nov 2025
Model description paper |
| 05 Nov 2025
| 05 Nov 2025
age_flow_line-1.0: a fast and accurate numerical age model for a pseudo-steady flow tube of an ice sheet
Frédéric Parrenin
CORRESPONDING AUTHOR
Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP, IGE, 38000 Grenoble, France
Ailsa Chung
Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP, IGE, 38000 Grenoble, France
Carlos Martín
British Antarctic Survey, Cambridge, UK
Related authors
Felix Pollak, Émilie Capron, Zanna Chase, Polychronis C. Tzedakis, Frédéric Parrenin, and Lenneke Jong
EGUsphere, https://doi.org/10.5194/egusphere-2026-6154, https://doi.org/10.5194/egusphere-2026-6154, 2026
This preprint is open for discussion and under review for Climate of the Past (CP).
Short summary
Short summary
We present a new data compilation of marine and terrestrial records covering the last 1.5 Myr. A particular focus lies on the comparatively scarce terrestrial archives. For each record, we evaluate the intensity of glacials, interglacials, and terminations across this interval. We examine which stages were especially strong or weak, whether there were coherent patterns or divergences among the records, and whether glacial and interglacial strength depends on each other.
Ailsa Chung, Yéva Jeaumot, Frédéric Parrenin, Daniel Steinhage, and Olaf Eisen
EGUsphere, https://doi.org/10.5194/egusphere-2026-4351, https://doi.org/10.5194/egusphere-2026-4351, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
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We use a 2.5D ice flow model constrained by radar data to estimate the age of ice, basal conditions and particle paths along a flow line from Dome Fuji (DF) to the EPICA Dronning Maud Land ice core site (EDML), Antarctica. Modelled basal melt rates are highest in bedrock dips and stagnant ice occurs on or slightly downstream of bedrock highs. At EDML, particle paths show that the deepest ice may originate 130 km upstream. We also identify a potential old-ice area (>1 Ma), ~200 km from DF.
Victor van Aanderen, Aurélien Quiquet, Christophe Dumas, Elisabeth Michel, Frederic Parrenin, Catherine Ritz, and Kévin Jiguet-Covex
EGUsphere, https://doi.org/10.5194/egusphere-2026-5288, https://doi.org/10.5194/egusphere-2026-5288, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
Ice cores from Dome C provide one of the longest climate records, and Beyond EPICA aims to extend it further. Interpreting these records requires knowing whether Dome C has remained fixed. Using an ice sheet model spanning 800,000 years, we show Dome C has shifted several km during glacial cycles, driven by grounding line migration in the Aurora Subglacial Basin. This displacement can introduce age errors of several tens of thousands of years when interpreting the ice-core record.
Yéva Jeaumot, Frédéric Parrenin, Ailsa Chung, Olaf Eisen, Daniel Steinhage, Robert Mulvaney, Marie G. P. Cavitte, David A. Lilien, and Emilie Capron
EGUsphere, https://doi.org/10.5194/egusphere-2026-4174, https://doi.org/10.5194/egusphere-2026-4174, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
To choose good drilling sites and interpret ice cores correctly, scientists need reliable estimates of ice age at each depth. We developed a new way to model how ice behaves at the base of ice sheets, where it can melt or stop moving entirely, using radar data from Antarctica. Our estimates matched real measurements at a well-studied site, revealed a layer of stagnant ice at another, and predicted that a newly proposed drilling site could yield ice over two million years old.
Etienne Legrain, Nathan Stevenard, Emilie Capron, Frédéric Parrenin, and Natalia Vazquez Riveiros
Clim. Past, 22, 1223–1240, https://doi.org/10.5194/cp-22-1223-2026, https://doi.org/10.5194/cp-22-1223-2026, 2026
Short summary
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To better understand climate drivers during a warm period ~200,000 years ago, we reconstructed global surface temperature using 132 marine records placed on a common timeline. We found strong hemispheric differences and showed that the warmest phase occurred despite lower CO2 levels. In addition, we suggest that extreme orbital forcing temporarily shifted the climate into the older 41,000-year rhythm, resulting in a hybrid warm period shaped by both 100,000-year and 41,000-year climate dynamics.
Felix Pollak, Frédéric Parrenin, Emilie Capron, Zanna Chase, Lenneke Jong, and Etienne Legrain
Clim. Past, 22, 675–688, https://doi.org/10.5194/cp-22-675-2026, https://doi.org/10.5194/cp-22-675-2026, 2026
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The Mid-Pleistocene Transition (MPT) marked a shift towards extended glacial periods and amplitudes, while its underlying mechanisms are still disputed. Here, we present a new conceptual model, capable of reconstructing global ice volume over the past 2.6 Ma, including a shift in frequency and amplitude during the MPT. We find that a long-lasting, gradual trend in the Earth-climate system is most favourable in reconstructing the MPT and that it started over 2 Ma.
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.
Titouan Tcheng, Elise Fourré, Christophe Leroy-Dos Santos, Frédéric Parrenin, Emmanuel Le Meur, Frédéric Prié, Olivier Jossoud, Roxanne Jacob, Bénédicte Minster, Olivier Magand, Cécile Agosta, Niels Dutrievoz, Vincent Favier, Léa Baubant, Coralie Lassalle-Bernard, Mathieu Casado, Martin Werner, Alexandre Cauquoin, Laurent Arnaud, Bruno Jourdain, Ghislain Picard, Marie Bouchet, and Amaëlle Landais
The Cryosphere, 20, 1599–1618, https://doi.org/10.5194/tc-20-1599-2026, https://doi.org/10.5194/tc-20-1599-2026, 2026
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Studying Antarctic ice cores is crucial to assess past climate changes, as they hold historical climate data. This study examines multiple ice cores from three sites in coastal Adélie Land to see if combining cores improves data interpretability. It does at two sites, but at a third, wind-driven snow layer mixing limited benefits. We show that using multiple ice cores from one location can better uncover climate history, especially in areas with less wind disturbance.
Dong Li, Xueyuan Tang, Ailsa Chung, Frédéric Parrenin, and Bo Sun
EGUsphere, https://doi.org/10.5194/egusphere-2025-5165, https://doi.org/10.5194/egusphere-2025-5165, 2026
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China's first deep ice core drilling at Dome A aims to obtain continuous ice records older than one million years. Using radar data and a one-dimensional ice flow model, we estimated the age of ice layers across Dome A. Our results suggest that the bottom ice melts very little and highlight three areas that may preserve million-year-old ice. The findings provide guidance for future drilling and support international efforts to study the oldest ice in Antarctica.
Robert G. Bingham, Julien A. Bodart, Marie G. P. Cavitte, Ailsa Chung, Rebecca J. Sanderson, Johannes C. R. Sutter, Olaf Eisen, Nanna B. Karlsson, Joseph A. MacGregor, Neil Ross, Duncan A. Young, David W. Ashmore, Andreas Born, Winnie Chu, Xiangbin Cui, Reinhard Drews, Steven Franke, Vikram Goel, John W. Goodge, A. Clara J. Henry, Antoine Hermant, Benjamin H. Hills, Nicholas Holschuh, Michelle R. Koutnik, Gwendolyn J.-M. C. Leysinger Vieli, Emma J. MacKie, Elisa Mantelli, Carlos Martín, Felix S. L. Ng, Falk M. Oraschewski, Felipe Napoleoni, Frédéric Parrenin, Sergey V. Popov, Therese Rieckh, Rebecca Schlegel, Dustin M. Schroeder, Martin J. Siegert, Xueyuan Tang, Thomas O. Teisberg, Kate Winter, Shuai Yan, Harry Davis, Christine F. Dow, Tyler J. Fudge, Tom A. Jordan, Bernd Kulessa, Kenichi Matsuoka, Clara J. Nyqvist, Maryam Rahnemoonfar, Matthew R. Siegfried, Shivangini Singh, Vjeran Višnjević, Rodrigo Zamora, and Alexandra Zuhr
The Cryosphere, 19, 4611–4655, https://doi.org/10.5194/tc-19-4611-2025, https://doi.org/10.5194/tc-19-4611-2025, 2025
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The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative working together on these archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica and how this is being used to reconstruct past and to predict future ice and climate behaviour.
Ailsa Chung, Frédéric Parrenin, Robert Mulvaney, Luca Vittuari, Massimo Frezzotti, Antonio Zanutta, David A. Lilien, Marie G. P. Cavitte, and Olaf Eisen
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We applied an ice flow model to a flow line from the summit of Dome C to the Beyond EPICA ice core drill site on Little Dome C in Antarctica. Results show that the oldest ice at the drill site may be 1.12 Ma (at an age density of 20 kyr m-1) and originate from around 15 km upstream. We also discuss the nature of the 200–250 m thick basal layer which could be composed of stagnant ice, disturbed ice or even accreted ice (possibly containing debris).
Frédéric Parrenin, Marie Bouchet, Christo Buizert, Emilie Capron, Ellen Corrick, Russell Drysdale, Kenji Kawamura, Amaëlle Landais, Robert Mulvaney, Ikumi Oyabu, and Sune Olander Rasmussen
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The Paleochrono-1.1 probabilistic dating model allows users to derive a common and optimized chronology for several paleoclimatic sites from various archives (ice cores, speleothems, marine cores, lake cores, etc.). It combines prior sedimentation scenarios with chronological information such as dated horizons, dated intervals, stratigraphic links and (for ice cores) Δdepth observations. Paleochrono-1.1 is available under an open-source license.
Dominique Raynaud, Qiuzhen Yin, Emilie Capron, Zhipeng Wu, Frédéric Parrenin, André Berger, and Vladimir Lipenkov
Clim. Past, 20, 1269–1282, https://doi.org/10.5194/cp-20-1269-2024, https://doi.org/10.5194/cp-20-1269-2024, 2024
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There is a lack of reconstructions from Antarctic ice cores of the temperature during the summer, a critical season in terms of solar energy received, preventing a good understanding of the link between Antarctic past climate and astronomically induced insolation changes. Here, the variations in total air content in an Antarctic ice core are found to be correlated to local summer temperatures simulated with a climate model. This tracer can be used to reconstruct past local summer temperatures.
Marie Bouchet, Amaëlle Landais, Antoine Grisart, Frédéric Parrenin, Frédéric Prié, Roxanne Jacob, Elise Fourré, Emilie Capron, Dominique Raynaud, Vladimir Ya Lipenkov, Marie-France Loutre, Thomas Extier, Anders Svensson, Etienne Legrain, Patricia Martinerie, Markus Leuenberger, Wei Jiang, Florian Ritterbusch, Zheng-Tian Lu, and Guo-Min Yang
Clim. Past, 19, 2257–2286, https://doi.org/10.5194/cp-19-2257-2023, https://doi.org/10.5194/cp-19-2257-2023, 2023
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A new federative chronology for five deep polar ice cores retrieves 800 000 years of past climate variations with improved accuracy. Precise ice core timescales are key to studying the mechanisms linking changes in the Earth’s orbit to the diverse climatic responses (temperature and atmospheric greenhouse gas concentrations). To construct the chronology, new measurements from the oldest continuous ice core as well as glaciological modeling estimates were combined in a statistical model.
Zhuo Wang, Ailsa Chung, Daniel Steinhage, Frédéric Parrenin, Johannes Freitag, and Olaf Eisen
The Cryosphere, 17, 4297–4314, https://doi.org/10.5194/tc-17-4297-2023, https://doi.org/10.5194/tc-17-4297-2023, 2023
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We combine radar-based observed internal layer stratigraphy of the ice sheet with a 1-D ice flow model in the Dome Fuji region. This results in maps of age and age density of the basal ice, the basal thermal conditions, and reconstructed accumulation rates. Based on modeled age we then identify four potential candidates for ice which is potentially 1.5 Myr old. Our map of basal thermal conditions indicates that melting prevails over the presence of stagnant ice in the study area.
Ailsa Chung, Frédéric Parrenin, Daniel Steinhage, Robert Mulvaney, Carlos Martín, Marie G. P. Cavitte, David A. Lilien, Veit Helm, Drew Taylor, Prasad Gogineni, Catherine Ritz, Massimo Frezzotti, Charles O'Neill, Heinrich Miller, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 17, 3461–3483, https://doi.org/10.5194/tc-17-3461-2023, https://doi.org/10.5194/tc-17-3461-2023, 2023
Short summary
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We combined a numerical model with radar measurements in order to determine the age of ice in the Dome C region of Antarctica. Our results show that at the current ice core drilling sites on Little Dome C, the maximum age of the ice is almost 1.5 Ma. We also highlight a new potential drill site called North Patch with ice up to 2 Ma. Finally, we explore the nature of a stagnant ice layer at the base of the ice sheet which has been independently observed and modelled but is not well understood.
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
Short summary
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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.
Ikumi Oyabu, Kenji Kawamura, Shuji Fujita, Ryo Inoue, Hideaki Motoyama, Kotaro Fukui, Motohiro Hirabayashi, Yu Hoshina, Naoyuki Kurita, Fumio Nakazawa, Hiroshi Ohno, Konosuke Sugiura, Toshitaka Suzuki, Shun Tsutaki, Ayako Abe-Ouchi, Masashi Niwano, Frédéric Parrenin, Fuyuki Saito, and Masakazu Yoshimori
Clim. Past, 19, 293–321, https://doi.org/10.5194/cp-19-293-2023, https://doi.org/10.5194/cp-19-293-2023, 2023
Short summary
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We reconstructed accumulation rate around Dome Fuji, Antarctica, over the last 5000 years from 15 shallow ice cores and seven snow pits. We found a long-term decreasing trend in the preindustrial period, which may be associated with secular surface cooling and sea ice expansion. Centennial-scale variations were also found, which may partly be related to combinations of volcanic, solar and greenhouse gas forcings. The most rapid and intense increases of accumulation rate occurred since 1850 CE.
Felix Pollak, Émilie Capron, Zanna Chase, Polychronis C. Tzedakis, Frédéric Parrenin, and Lenneke Jong
EGUsphere, https://doi.org/10.5194/egusphere-2026-6154, https://doi.org/10.5194/egusphere-2026-6154, 2026
This preprint is open for discussion and under review for Climate of the Past (CP).
Short summary
Short summary
We present a new data compilation of marine and terrestrial records covering the last 1.5 Myr. A particular focus lies on the comparatively scarce terrestrial archives. For each record, we evaluate the intensity of glacials, interglacials, and terminations across this interval. We examine which stages were especially strong or weak, whether there were coherent patterns or divergences among the records, and whether glacial and interglacial strength depends on each other.
Ailsa Chung, Yéva Jeaumot, Frédéric Parrenin, Daniel Steinhage, and Olaf Eisen
EGUsphere, https://doi.org/10.5194/egusphere-2026-4351, https://doi.org/10.5194/egusphere-2026-4351, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
We use a 2.5D ice flow model constrained by radar data to estimate the age of ice, basal conditions and particle paths along a flow line from Dome Fuji (DF) to the EPICA Dronning Maud Land ice core site (EDML), Antarctica. Modelled basal melt rates are highest in bedrock dips and stagnant ice occurs on or slightly downstream of bedrock highs. At EDML, particle paths show that the deepest ice may originate 130 km upstream. We also identify a potential old-ice area (>1 Ma), ~200 km from DF.
Victor van Aanderen, Aurélien Quiquet, Christophe Dumas, Elisabeth Michel, Frederic Parrenin, Catherine Ritz, and Kévin Jiguet-Covex
EGUsphere, https://doi.org/10.5194/egusphere-2026-5288, https://doi.org/10.5194/egusphere-2026-5288, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
Ice cores from Dome C provide one of the longest climate records, and Beyond EPICA aims to extend it further. Interpreting these records requires knowing whether Dome C has remained fixed. Using an ice sheet model spanning 800,000 years, we show Dome C has shifted several km during glacial cycles, driven by grounding line migration in the Aurora Subglacial Basin. This displacement can introduce age errors of several tens of thousands of years when interpreting the ice-core record.
Yéva Jeaumot, Frédéric Parrenin, Ailsa Chung, Olaf Eisen, Daniel Steinhage, Robert Mulvaney, Marie G. P. Cavitte, David A. Lilien, and Emilie Capron
EGUsphere, https://doi.org/10.5194/egusphere-2026-4174, https://doi.org/10.5194/egusphere-2026-4174, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
To choose good drilling sites and interpret ice cores correctly, scientists need reliable estimates of ice age at each depth. We developed a new way to model how ice behaves at the base of ice sheets, where it can melt or stop moving entirely, using radar data from Antarctica. Our estimates matched real measurements at a well-studied site, revealed a layer of stagnant ice at another, and predicted that a newly proposed drilling site could yield ice over two million years old.
Amy C. F. King, Thomas K. Bauska, Amaëlle Landais, Carlos Martín, and Eric W. Wolff
Clim. Past, 22, 1291–1304, https://doi.org/10.5194/cp-22-1291-2026, https://doi.org/10.5194/cp-22-1291-2026, 2026
Short summary
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We show how measurements of nitrogen isotopes in Antarctic ice core records can be used to show dramatic thinning of an ice sheet during ice mass changes in the Holocene. Combining such measurements with proxies for ice sheet elevation could be a powerful tool for constraining the history of ice dynamics at sites which are sensitive to rapid changes, and could contribute to constraining ice sheet models.
Etienne Legrain, Nathan Stevenard, Emilie Capron, Frédéric Parrenin, and Natalia Vazquez Riveiros
Clim. Past, 22, 1223–1240, https://doi.org/10.5194/cp-22-1223-2026, https://doi.org/10.5194/cp-22-1223-2026, 2026
Short summary
Short summary
To better understand climate drivers during a warm period ~200,000 years ago, we reconstructed global surface temperature using 132 marine records placed on a common timeline. We found strong hemispheric differences and showed that the warmest phase occurred despite lower CO2 levels. In addition, we suggest that extreme orbital forcing temporarily shifted the climate into the older 41,000-year rhythm, resulting in a hybrid warm period shaped by both 100,000-year and 41,000-year climate dynamics.
Harry J. Davis, Robert G. Bingham, Carlos Martín, Elizabeth R. Thomas, Andrew S. Hein, and Anna E. Hogg
The Cryosphere, 20, 2735–2756, https://doi.org/10.5194/tc-20-2735-2026, https://doi.org/10.5194/tc-20-2735-2026, 2026
Short summary
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Ice in the southern Antarctic Peninsula is experiencing major ice changes today and predicting the rate at which this may continue is important. One way to address this knowledge gap would be to retrieve a past climate record from an ice core. We identify a suitable site using a model constrained by radar and shallow ice core data. We find a climate record spanning the Holocene can certainly be extracted here, but a potential continuous climate record here could extend back ~ 30 000 years.
Felix Pollak, Frédéric Parrenin, Emilie Capron, Zanna Chase, Lenneke Jong, and Etienne Legrain
Clim. Past, 22, 675–688, https://doi.org/10.5194/cp-22-675-2026, https://doi.org/10.5194/cp-22-675-2026, 2026
Short summary
Short summary
The Mid-Pleistocene Transition (MPT) marked a shift towards extended glacial periods and amplitudes, while its underlying mechanisms are still disputed. Here, we present a new conceptual model, capable of reconstructing global ice volume over the past 2.6 Ma, including a shift in frequency and amplitude during the MPT. We find that a long-lasting, gradual trend in the Earth-climate system is most favourable in reconstructing the MPT and that it started over 2 Ma.
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
Short summary
Short summary
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.
Titouan Tcheng, Elise Fourré, Christophe Leroy-Dos Santos, Frédéric Parrenin, Emmanuel Le Meur, Frédéric Prié, Olivier Jossoud, Roxanne Jacob, Bénédicte Minster, Olivier Magand, Cécile Agosta, Niels Dutrievoz, Vincent Favier, Léa Baubant, Coralie Lassalle-Bernard, Mathieu Casado, Martin Werner, Alexandre Cauquoin, Laurent Arnaud, Bruno Jourdain, Ghislain Picard, Marie Bouchet, and Amaëlle Landais
The Cryosphere, 20, 1599–1618, https://doi.org/10.5194/tc-20-1599-2026, https://doi.org/10.5194/tc-20-1599-2026, 2026
Short summary
Short summary
Studying Antarctic ice cores is crucial to assess past climate changes, as they hold historical climate data. This study examines multiple ice cores from three sites in coastal Adélie Land to see if combining cores improves data interpretability. It does at two sites, but at a third, wind-driven snow layer mixing limited benefits. We show that using multiple ice cores from one location can better uncover climate history, especially in areas with less wind disturbance.
Vikram Goel, Carlos Martín, Kenichi Matsuoka, Bhanu Pratap, Geir Moholdt, Rahul Dey, Chavarukonam M. Laluraj, and Meloth Thamban
The Cryosphere, 20, 1363–1378, https://doi.org/10.5194/tc-20-1363-2026, https://doi.org/10.5194/tc-20-1363-2026, 2026
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We identified an ideal site in coastal East Antarctica for extracting ice core that contain detailed climate records dating back 20 000 years. We surveyed two ice rises combining radar measurements with ice flow modeling to assess their suitability. One site emerged as optimal, offering well-preserved climate history with high temporal resolution. An ice core record from this site could help us understand historical interactions between sea ice, winds, and precipitation patterns in the region.
Dong Li, Xueyuan Tang, Ailsa Chung, Frédéric Parrenin, and Bo Sun
EGUsphere, https://doi.org/10.5194/egusphere-2025-5165, https://doi.org/10.5194/egusphere-2025-5165, 2026
Short summary
Short summary
China's first deep ice core drilling at Dome A aims to obtain continuous ice records older than one million years. Using radar data and a one-dimensional ice flow model, we estimated the age of ice layers across Dome A. Our results suggest that the bottom ice melts very little and highlight three areas that may preserve million-year-old ice. The findings provide guidance for future drilling and support international efforts to study the oldest ice in Antarctica.
Álvaro Arenas-Pingarrón, Alex M. Brisbourne, Carlos Martín, Hugh F. J. Corr, Carl Robinson, Tom A. Jordan, and Paul V. Brennan
The Cryosphere, 19, 4657–4670, https://doi.org/10.5194/tc-19-4657-2025, https://doi.org/10.5194/tc-19-4657-2025, 2025
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Synthetic Aperture Radar (SAR) imaging is essential for deep englacial observations. Each pixel is formed by averaging the radar echoes within an antenna beamwidth, but the echo diversity is lost after the average. We improve the SAR interpretation if three sub-images are formed with different sub-beamwidths: each is coloured in red, green, or blue, and they are overlapped, creating a coloured image. Interpreters will better identify the slopes of internal layers, crevasses, and layer roughness.
Robert G. Bingham, Julien A. Bodart, Marie G. P. Cavitte, Ailsa Chung, Rebecca J. Sanderson, Johannes C. R. Sutter, Olaf Eisen, Nanna B. Karlsson, Joseph A. MacGregor, Neil Ross, Duncan A. Young, David W. Ashmore, Andreas Born, Winnie Chu, Xiangbin Cui, Reinhard Drews, Steven Franke, Vikram Goel, John W. Goodge, A. Clara J. Henry, Antoine Hermant, Benjamin H. Hills, Nicholas Holschuh, Michelle R. Koutnik, Gwendolyn J.-M. C. Leysinger Vieli, Emma J. MacKie, Elisa Mantelli, Carlos Martín, Felix S. L. Ng, Falk M. Oraschewski, Felipe Napoleoni, Frédéric Parrenin, Sergey V. Popov, Therese Rieckh, Rebecca Schlegel, Dustin M. Schroeder, Martin J. Siegert, Xueyuan Tang, Thomas O. Teisberg, Kate Winter, Shuai Yan, Harry Davis, Christine F. Dow, Tyler J. Fudge, Tom A. Jordan, Bernd Kulessa, Kenichi Matsuoka, Clara J. Nyqvist, Maryam Rahnemoonfar, Matthew R. Siegfried, Shivangini Singh, Vjeran Višnjević, Rodrigo Zamora, and Alexandra Zuhr
The Cryosphere, 19, 4611–4655, https://doi.org/10.5194/tc-19-4611-2025, https://doi.org/10.5194/tc-19-4611-2025, 2025
Short summary
Short summary
The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative working together on these archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica and how this is being used to reconstruct past and to predict future ice and climate behaviour.
Ailsa Chung, Frédéric Parrenin, Robert Mulvaney, Luca Vittuari, Massimo Frezzotti, Antonio Zanutta, David A. Lilien, Marie G. P. Cavitte, and Olaf Eisen
The Cryosphere, 19, 4125–4140, https://doi.org/10.5194/tc-19-4125-2025, https://doi.org/10.5194/tc-19-4125-2025, 2025
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We applied an ice flow model to a flow line from the summit of Dome C to the Beyond EPICA ice core drill site on Little Dome C in Antarctica. Results show that the oldest ice at the drill site may be 1.12 Ma (at an age density of 20 kyr m-1) and originate from around 15 km upstream. We also discuss the nature of the 200–250 m thick basal layer which could be composed of stagnant ice, disturbed ice or even accreted ice (possibly containing debris).
Ole Zeising, Álvaro Arenas-Pingarrón, Alex M. Brisbourne, and Carlos Martín
The Cryosphere, 19, 2355–2363, https://doi.org/10.5194/tc-19-2355-2025, https://doi.org/10.5194/tc-19-2355-2025, 2025
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Ice crystal orientation influences how glacier ice deforms. Radar polarimetry is commonly used to study the bulk ice crystal orientation, but the often used coherence method only provides information of the shallow ice in fast-flowing areas. This study shows that reducing the bandwidth of high-bandwidth radar data significantly enhances the depth limit of the coherence method. This improvement helps us to better understand ice dynamics in fast-flowing ice streams.
Frédéric Parrenin, Marie Bouchet, Christo Buizert, Emilie Capron, Ellen Corrick, Russell Drysdale, Kenji Kawamura, Amaëlle Landais, Robert Mulvaney, Ikumi Oyabu, and Sune Olander Rasmussen
Geosci. Model Dev., 17, 8735–8750, https://doi.org/10.5194/gmd-17-8735-2024, https://doi.org/10.5194/gmd-17-8735-2024, 2024
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The Paleochrono-1.1 probabilistic dating model allows users to derive a common and optimized chronology for several paleoclimatic sites from various archives (ice cores, speleothems, marine cores, lake cores, etc.). It combines prior sedimentation scenarios with chronological information such as dated horizons, dated intervals, stratigraphic links and (for ice cores) Δdepth observations. Paleochrono-1.1 is available under an open-source license.
Dominique Raynaud, Qiuzhen Yin, Emilie Capron, Zhipeng Wu, Frédéric Parrenin, André Berger, and Vladimir Lipenkov
Clim. Past, 20, 1269–1282, https://doi.org/10.5194/cp-20-1269-2024, https://doi.org/10.5194/cp-20-1269-2024, 2024
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There is a lack of reconstructions from Antarctic ice cores of the temperature during the summer, a critical season in terms of solar energy received, preventing a good understanding of the link between Antarctic past climate and astronomically induced insolation changes. Here, the variations in total air content in an Antarctic ice core are found to be correlated to local summer temperatures simulated with a climate model. This tracer can be used to reconstruct past local summer temperatures.
Marie Bouchet, Amaëlle Landais, Antoine Grisart, Frédéric Parrenin, Frédéric Prié, Roxanne Jacob, Elise Fourré, Emilie Capron, Dominique Raynaud, Vladimir Ya Lipenkov, Marie-France Loutre, Thomas Extier, Anders Svensson, Etienne Legrain, Patricia Martinerie, Markus Leuenberger, Wei Jiang, Florian Ritterbusch, Zheng-Tian Lu, and Guo-Min Yang
Clim. Past, 19, 2257–2286, https://doi.org/10.5194/cp-19-2257-2023, https://doi.org/10.5194/cp-19-2257-2023, 2023
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A new federative chronology for five deep polar ice cores retrieves 800 000 years of past climate variations with improved accuracy. Precise ice core timescales are key to studying the mechanisms linking changes in the Earth’s orbit to the diverse climatic responses (temperature and atmospheric greenhouse gas concentrations). To construct the chronology, new measurements from the oldest continuous ice core as well as glaciological modeling estimates were combined in a statistical model.
Zhuo Wang, Ailsa Chung, Daniel Steinhage, Frédéric Parrenin, Johannes Freitag, and Olaf Eisen
The Cryosphere, 17, 4297–4314, https://doi.org/10.5194/tc-17-4297-2023, https://doi.org/10.5194/tc-17-4297-2023, 2023
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We combine radar-based observed internal layer stratigraphy of the ice sheet with a 1-D ice flow model in the Dome Fuji region. This results in maps of age and age density of the basal ice, the basal thermal conditions, and reconstructed accumulation rates. Based on modeled age we then identify four potential candidates for ice which is potentially 1.5 Myr old. Our map of basal thermal conditions indicates that melting prevails over the presence of stagnant ice in the study area.
Ailsa Chung, Frédéric Parrenin, Daniel Steinhage, Robert Mulvaney, Carlos Martín, Marie G. P. Cavitte, David A. Lilien, Veit Helm, Drew Taylor, Prasad Gogineni, Catherine Ritz, Massimo Frezzotti, Charles O'Neill, Heinrich Miller, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 17, 3461–3483, https://doi.org/10.5194/tc-17-3461-2023, https://doi.org/10.5194/tc-17-3461-2023, 2023
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We combined a numerical model with radar measurements in order to determine the age of ice in the Dome C region of Antarctica. Our results show that at the current ice core drilling sites on Little Dome C, the maximum age of the ice is almost 1.5 Ma. We also highlight a new potential drill site called North Patch with ice up to 2 Ma. Finally, we explore the nature of a stagnant ice layer at the base of the ice sheet which has been independently observed and modelled but is not well understood.
Isobel Rowell, Carlos Martin, Robert Mulvaney, Helena Pryer, Dieter Tetzner, Emily Doyle, Hara Madhav Talasila, Jilu Li, and Eric Wolff
Clim. Past, 19, 1699–1714, https://doi.org/10.5194/cp-19-1699-2023, https://doi.org/10.5194/cp-19-1699-2023, 2023
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We present an age scale for a new type of ice core from a vulnerable region in West Antarctic, which is lacking in longer-term (greater than a few centuries) ice core records. The Sherman Island core extends to greater than 1 kyr. We provide modelling evidence for the potential of a 10 kyr long core. We show that this new type of ice core can be robustly dated and that climate records from this core will be a significant addition to existing regional climate records.
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.
Ikumi Oyabu, Kenji Kawamura, Shuji Fujita, Ryo Inoue, Hideaki Motoyama, Kotaro Fukui, Motohiro Hirabayashi, Yu Hoshina, Naoyuki Kurita, Fumio Nakazawa, Hiroshi Ohno, Konosuke Sugiura, Toshitaka Suzuki, Shun Tsutaki, Ayako Abe-Ouchi, Masashi Niwano, Frédéric Parrenin, Fuyuki Saito, and Masakazu Yoshimori
Clim. Past, 19, 293–321, https://doi.org/10.5194/cp-19-293-2023, https://doi.org/10.5194/cp-19-293-2023, 2023
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We reconstructed accumulation rate around Dome Fuji, Antarctica, over the last 5000 years from 15 shallow ice cores and seven snow pits. We found a long-term decreasing trend in the preindustrial period, which may be associated with secular surface cooling and sea ice expansion. Centennial-scale variations were also found, which may partly be related to combinations of volcanic, solar and greenhouse gas forcings. The most rapid and intense increases of accumulation rate occurred since 1850 CE.
M. Reza Ershadi, Reinhard Drews, Carlos Martín, Olaf Eisen, Catherine Ritz, Hugh Corr, Julia Christmann, Ole Zeising, Angelika Humbert, and Robert Mulvaney
The Cryosphere, 16, 1719–1739, https://doi.org/10.5194/tc-16-1719-2022, https://doi.org/10.5194/tc-16-1719-2022, 2022
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Radio waves transmitted through ice split up and inform us about the ice sheet interior and orientation of single ice crystals. This can be used to infer how ice flows and improve projections on how it will evolve in the future. Here we used an inverse approach and developed a new algorithm to infer ice properties from observed radar data. We applied this technique to the radar data obtained at two EPICA drilling sites, where ice cores were used to validate our results.
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Short summary
We developed a new numerical age solver for a pseudo-steady flow tube of an ice sheet. Thanks to a new coordinate system which tracks the trajectories and a change of the time variable, our scheme combines the advantages of Eulerian and Lagrangian schemes: no numerical diffusion and no dilution of tracers. Our model is so fast that it is easy to optimize its parameters. Our model is made available to the ice sheet community as an easy to use open-source software coded in python.
We developed a new numerical age solver for a pseudo-steady flow tube of an ice sheet. Thanks to...
