Articles | Volume 9, issue 1
https://doi.org/10.5194/tc-9-385-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/tc-9-385-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
20 Feb 2015
Research article |
| 20 Feb 2015
Seismic wave propagation in anisotropic ice – Part 2: Effects of crystal anisotropy in geophysical data
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
Karlsruhe Institute of Technology, Karlsruhe, Germany
now at: Scripps Institution of Oceanography, University of California, San Diego, USA
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
Department Geosciences, University of Bremen, Bremen, Germany
C. Hofstede
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
A. Lambrecht
Bavarian Academy for Sciences and Humanities, Munich, Germany
Bavarian Academy for Sciences and Humanities, Munich, Germany
H. Miller
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
D. Steinhage
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
T. Binder
Interdisciplinary Center for Scientific Computing, University of Heidelberg, Heidelberg, Germany
now at: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
I. Weikusat
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
Related authors
No articles found.
Martin Rückamp, Gong Cheng, Karlheinz Gutjahr, Marco Möller, Petri K. E. Pellikka, and Christoph Mayer
The Cryosphere, 20, 2999–3024, https://doi.org/10.5194/tc-20-2999-2026, https://doi.org/10.5194/tc-20-2999-2026, 2026
Short summary
Short summary
The study simulates the 21st-century evolution of Great Aletsch Glacier and Hintereisferner using full-Stokes ice dynamics and surface mass balance under different emission scenarios. Results show significant ice loss, with Hintereisferner expected to disappear by mid-century. Great Aletsch Glacier vanish by the end of the century under high-emission scenarios, but persist under lower-emission scenarios. These trends agree with large-scale models except some variability.
Theresa Dobler, Wilfried Hagg, Martin Rückamp, Thorsten Seehaus, and Christoph Mayer
The Cryosphere, 20, 2531–2555, https://doi.org/10.5194/tc-20-2531-2026, https://doi.org/10.5194/tc-20-2531-2026, 2026
Short summary
Short summary
We studied how a glacier in the Austrian Alps moves more slowly over time due to climate change. By combining long-term field data with recent aerial images, we show how thinning reduce glacier flow. Our findings help understand changes in glacier behavior in a warming climate.
Steven Franke, Daniel Steinhage, Veit Helm, Tobias Binder, Uwe Nixdorf, Heinrich Miller, Angelika Humbert, Daniela Jansen, Graeme Eagles, Hannes Eisermann, Wilfried Jokat, Antonia Ruppel, Reinhard Drews, Alexandra Zuhr, Amelie Driemel, Andreas Walter, Peter Konopatzky, Robin Heß, Antonie Haas, Roland Koppe, Pascal H. Andreas, and Olaf Eisen
The Cryosphere, 20, 2485–2530, https://doi.org/10.5194/tc-20-2485-2026, https://doi.org/10.5194/tc-20-2485-2026, 2026
Short summary
Short summary
This review synthesizes 30 years of Alfred Wegener Institute’s (AWI) airborne radar research in Antarctica and Greenland, detailing six radar systems and their applications in studying ice dynamics, basal properties, and subglacial landscapes. Moreover, it introduces the public release of AWI's airborne radar datasets via the Radar Data over Polar Ice Sheets Viewer and PANGAEA, ensuring findable, accessible, interoperable, and reusable access for future polar research.
Akash M. Patil, Christoph Mayer, Theo M. Jenk, Astrid Lambrecht, Thorsten Seehaus, Alexander R. Groos, and Michelle Worek
EGUsphere, https://doi.org/10.5194/egusphere-2026-1721, https://doi.org/10.5194/egusphere-2026-1721, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
Our study focused on understanding how a warming climate affects the Aletsch glacier accumulation area. We used multi-year radar measurements and direct firn‑core analyses to estimate changes in density, layering, and compaction of snow-to-ice over a year. Our results show that the upper layers of the glacier are changing faster due to stronger summer melt in the lower parts of the accumulation zone. Our findings help to improve firn densification models and glacier mass-balance estimation.
Francesca Pellicciotti, Adrià Fontrodona-Bach, David R. Rounce, Catriona L. Fyffe, Leif S. Anderson, Álvaro Ayala, Ben W. Brock, Pascal Buri, Stefan Fugger, Koji Fujita, Prateek Gantayat, Alexander R. Groos, Walter Immerzeel, Marin Kneib, Christoph Mayer, Shelley MacDonell, Michael McCarthy, James McPhee, Evan Miles, Heather Purdie, Ekaterina Rets, Akiko Sakai, Thomas E. Shaw, Jakob Steiner, Patrick Wagnon, and Alex Winter-Billington
The Cryosphere, 20, 1895–1928, https://doi.org/10.5194/tc-20-1895-2026, https://doi.org/10.5194/tc-20-1895-2026, 2026
Short summary
Short summary
Rock debris covers many of the world glaciers, modifying the transfer of atmospheric energy to the debris and into the ice. Models of different complexity simulate this process, and we compare 15 models at 9 sites to show that the most complex models at the debris-atmosphere interface have the highest performance. However, we lack debris properties and their derivation from measurements is ambiguous, hindering global modelling and calling for both model development and data collection.
Lea Hartl, Jakob Abermann, Ayla Akgün, Giulia Bertolotti, Tobias Bolch, Svenja Conzelmann, Codrut-Andrei Diaconu, Iris Hansche, Anne Hartig, Anna Haut, Kay Helfricht, Bernhard Hynek, Marie Sophie Kaucher, Andreas Kellerer-Pirklbauer, Ann Christin Kogel, Julie Krippes, Marcela Violeta Lauria, Christoph Mayer, Jan-Christoph Otto, Rainer Prinz, Sina Prölß, Lorenzo Rieg, Lea Schönleber, Gabriele Schwaizer, Bernd Seiser, Martin Stocker-Waldhuber, Markus Strudl, Martin Verhounik, and Harald Zandler
EGUsphere, https://doi.org/10.5194/egusphere-2026-1241, https://doi.org/10.5194/egusphere-2026-1241, 2026
This preprint is open for discussion and under review for The Cryosphere (TC).
Short summary
Short summary
We mapped glacier outlines in Austria using recent, high resolution imagery. The resulting glacier inventory provides an update on glacier area in Austria in 2021-2023. More than 30% of glacier area was lost and 95 glaciers have disappeared since the mid-2000s. Glacier recession is accelerating and regular updates to glacier inventories are needed to understand downstream changes to the hydrological system, quantify glacier mass loss, and support planning and adaptation measures.
Julien A. Bodart, Vjeran Višnjević, Steven Franke, Veit Helm, Olaf Eisen, Antoine Hermant, Alexandra M. Zuhr, Daniel Steinhage, and Johannes C. R. Sutter
The Cryosphere, 20, 1379–1404, https://doi.org/10.5194/tc-20-1379-2026, https://doi.org/10.5194/tc-20-1379-2026, 2026
Short summary
Short summary
We used radar data and computer models to study layers within Antarctic ice that record past snowfall and ice-sheet changes. These layers, called isochrones, are seldomly used to model Antarctica’s past. By comparing radar observations with simulations, we show how they can greatly improve model accuracy and provide two new datasets to help refine future reconstructions of Antarctic ice evolution.
Mirko Scheinert, Weisen Shen, Richard C. Aster, Lambert Caron, Michael D. Hartinger, Matt A. King, Andrew Lloyd, Anya M. Reading, J. Paul Winberry, Terry Wilson, Lucilla Alfonsi, Michael J. Bentley, Eric Buchta, Thomas Y. Chen, Peter J. Clarke, Jörg Ebbing, Olaf Eisen, Natalya Gomez, Esra Günaydın, Samantha Hansen, Erik R. Ivins, Achraf Koulali, Grace A. Nield, Frederick Richards, Mahmut O. Selbesoglu, Stephanie Sherman, Pippa L. Whitehouse, and Matthias Willen
EGUsphere, https://doi.org/10.5194/egusphere-2025-6370, https://doi.org/10.5194/egusphere-2025-6370, 2026
Short summary
Short summary
With an ongoing mass loss the Antarctic Ice Sheet contributes to global-mean sea level rise at a rate of 0.4 mm/a. Thus, it plays a key role in global climate and provides a natural laboratory to study processes that interlink cryosphere, solid Earth, atmosphere and ocean. We discuss how GNSS and seismic networks in Antarctica were used to significantly advance our understanding of these processes, and how they should be maintained and extended to answer key science questions in the future.
Valerie Reppert, Olaf Eisen, Holger Schmithüsen, Stefanie Arndt, Guido Ascenso, Linda Ort, and Zsófia Jurányi
EGUsphere, https://doi.org/10.5194/egusphere-2025-5199, https://doi.org/10.5194/egusphere-2025-5199, 2025
Short summary
Short summary
We analyzed 33 years of snow accumulation measurements at Neumayer Station, Antarctica, to understand changes in the amount of snow building up on the surface over time. The long-term, high-resolution data show mostly stable accumulation, but rare positive extremes appeared in 2021 and 2023. Seasonal and multi-year patterns were identified, providing valuable data to improve climate models and satellite observations.
Akash M. Patil, Christoph Mayer, Thorsten Seehaus, Alexander R. Groos, and Andreas Bauder
The Cryosphere, 19, 5547–5577, https://doi.org/10.5194/tc-19-5547-2025, https://doi.org/10.5194/tc-19-5547-2025, 2025
Short summary
Short summary
We studied how the density of snow to ice transition varies with depth in the Aletsch glacier using radar-based field measurements and some simple models. We showed that it is possible to track how much snow has accumulated in the last 10–14 years. This helps improve the uncertainties in glacier mass balance estimates. Overall, by utilising non-invasive radar techniques and models, we provide a novel approach to understanding the evolution of glaciers under regional climate conditions.
Marcel Dreier, Moritz Koch, Nora Gourmelon, Norbert Blindow, Daniel Steinhage, Fei Wu, Thorsten Seehaus, Matthias Braun, Andreas Maier, and Vincent Christlein
The Cryosphere, 19, 5337–5359, https://doi.org/10.5194/tc-19-5337-2025, https://doi.org/10.5194/tc-19-5337-2025, 2025
Short summary
Short summary
In this paper, we present a ready-to-use benchmark dataset to train machine learning approaches for detecting ice thickness from radar data. It includes radargrams of glaciers and ice sheets alongside annotations for their air–ice and ice–bedrock boundary. Furthermore, we introduce a baseline model and evaluate the influence of several geographical and glaciological factors on the performance of our model.
Charlotte M. Carter, Steven Franke, Daniela Jansen, Chris R. Stokes, Veit Helm, John Paden, and Olaf Eisen
The Cryosphere, 19, 5299–5315, https://doi.org/10.5194/tc-19-5299-2025, https://doi.org/10.5194/tc-19-5299-2025, 2025
Short summary
Short summary
The subglacial landforms beneath actively fast-flowing ice in Greenland have not been explored in detail, as digital elevation models have not had a high enough resolution to see these features. We use swath radar imaging to visualise landforms at the onset of an ice stream, revealing mega-scale glacial lineations, that would usually be assumed to be indicative of faster ice flow than the current velocities. Interpretation of the landscape also gives an indication of the properties of the bed.
Paul D. Bons, Yuanbang Hu, M.-Gema Llorens, Steven Franke, Nicolas Stoll, Ilka Weikusat, Julien Westhoff, and Yu Zhang
The Cryosphere, 19, 5095–5109, https://doi.org/10.5194/tc-19-5095-2025, https://doi.org/10.5194/tc-19-5095-2025, 2025
Short summary
Short summary
What causes folds in ice layers from the km scale down to the scale visible in the drill core: buckle folding due to variations in viscosity between layers, or the effect of mechanical anisotropy of ice due to an alignment of the crystal-lattice planes? Power spectra of folds in ice, a biotite schist, and numerical simulations show that folding in ice is due to the anisotropy, as the folds are self-similar, meaning that there is no characteristic fold scale that would result from buckle folding.
Florian Painer, Sepp Kipfstuhl, Martyn Drury, Tsutomu Uchida, Johannes Freitag, and Ilka Weikusat
The Cryosphere, 19, 5023–5044, https://doi.org/10.5194/tc-19-5023-2025, https://doi.org/10.5194/tc-19-5023-2025, 2025
Short summary
Short summary
Air clathrate hydrates trap ancient air in the deeper part of ice sheets. We use digital microscopy and automated image analysis to investigate the evolution of number, size, and shape of air clathrate hydrates from 1250 m depth to the bottom of the ice sheet. We confirm the previously found relation of changes in number and size with past climate and find a connection of their shape to changes in ice deformation. The results will help us to better understand air clathrate hydrates in deep ice.
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
Short summary
Short summary
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).
Miguel Moreno, André Lamott, Sepp Kipfstuhl, Ilka Weikusat, María-Gema Llorens, Yannick Heiser, and Dorthe Dahl-Jensen
EGUsphere, https://doi.org/10.5194/egusphere-2025-3647, https://doi.org/10.5194/egusphere-2025-3647, 2025
Short summary
Short summary
By scanning a Greenland ice core, we studied the changes in ice flow. We found that during past rapid climate changes, the size of ice grains and the amount of impurities were the main factors controlling how the ice deformed. We found that other deep, structural properties of the ice did not change in the cores studied, suggesting they were not the primary cause of the variations in flow.
Nicolas Stoll, Ilka Weikusat, Daniela Jansen, Paul Bons, Kyra Darányi, Julien Westhoff, María-Gema Llorens, David Wallis, Jan Eichler, Tomotaka Saruya, Tomoyuki Homma, Sune Olander Rasmussen, Giulia Sinnl, Anders Svensson, Martyn Drury, Frank Wilhelms, Sepp Kipfstuhl, Dorthe Dahl-Jensen, and Johanna Kerch
The Cryosphere, 19, 3805–3830, https://doi.org/10.5194/tc-19-3805-2025, https://doi.org/10.5194/tc-19-3805-2025, 2025
Short summary
Short summary
A better understanding of ice flow requires more observational data. The EastGRIP core is the first ice core through an active ice stream. We discuss crystal orientation data determining the present deformation regimes. A comparison with other deep cores shows the unique properties of EastGRIP and shows that deep ice likely originates from the Eemian. We further show that the overall plug flow of NEGIS is characterised by many small-scale variations, which remain to be considered in ice flow models.
Neil Ross, Rebecca J. Sanderson, Bernd Kulessa, Martin Siegert, Guy J. G. Paxman, Keir A. Nichols, Matthew R. Siegfried, Stewart S. R. Jamieson, Michael J. Bentley, Tom A. Jordan, Christine L. Batchelor, David Small, Olaf Eisen, Kate Winter, Robert G. Bingham, S. Louise Callard, Rachel Carr, Christine F. Dow, Helen A. Fricker, Emily Hill, Benjamin H. Hills, Coen Hofstede, Hafeez Jeofry, Felipe Napoleoni, and Wilson Sauthoff
EGUsphere, https://doi.org/10.5194/egusphere-2025-3625, https://doi.org/10.5194/egusphere-2025-3625, 2025
Short summary
Short summary
We review previous research into a group of fast-flowing Antarctic ice streams, the Foundation-Patuxent-Academy System. Previously, we knew relatively little how these ice streams flow, how they interact with the ocean, what their geological history was, and how they might evolve in a warming world. By reviewing existing information on these ice streams, we identify the future research needed to determine how they function, and their potential contribution to global sea level rise.
Ole Zeising, Tore Hattermann, Lars Kaleschke, Sophie Berger, Olaf Boebel, Reinhard Drews, M. Reza Ershadi, Tanja Fromm, Frank Pattyn, Daniel Steinhage, and Olaf Eisen
The Cryosphere, 19, 2837–2854, https://doi.org/10.5194/tc-19-2837-2025, https://doi.org/10.5194/tc-19-2837-2025, 2025
Short summary
Short summary
Basal melting of ice shelves impacts the mass loss of the Antarctic Ice Sheet. This study focuses on the Ekström Ice Shelf in East Antarctica, using multiyear data from an autonomous radar system. Results show a surprising seasonal pattern of high melt rates in winter and spring. The seasonalities of sea-ice growth and ocean density indicate that, in winter, dense water enhances plume activity and melt rates. Understanding these dynamics is crucial for improving future mass balance projections.
Hameed Moqadam and Olaf Eisen
The Cryosphere, 19, 2159–2196, https://doi.org/10.5194/tc-19-2159-2025, https://doi.org/10.5194/tc-19-2159-2025, 2025
Short summary
Short summary
This is an overview of methodologies that have been applied to map the internal reflection horizons, or ice-layer boundaries, of ice sheets on Earth and other planets. We briefly explain radar applications in glaciology and the methods which have been used and published. There are summaries of the published work of the last 2 decades. Finally, we conclude by introducing the gaps and opportunities for further advancement in this field, and we present possible future directions.
Tamara Annina Gerber, David A. Lilien, Niels F. Nymand, Daniel Steinhage, Olaf Eisen, and Dorthe Dahl-Jensen
The Cryosphere, 19, 1955–1971, https://doi.org/10.5194/tc-19-1955-2025, https://doi.org/10.5194/tc-19-1955-2025, 2025
Short summary
Short summary
This study examines how anisotropic scattering and birefringence affect radar signals in ice sheets. Using data from northeast Greenland, we show that anisotropic scattering – driven by subtle ice crystal orientation changes – dominates the azimuthal power response. We find a strong link between scattering strength, orientation, and stratigraphy. This suggests anisotropic scattering can reveal crystal fabric orientation and differentiate ice units from distinct climatic periods.
Steven Franke, Daniel Steinhage, Veit Helm, Alexandra M. Zuhr, Julien A. Bodart, Olaf Eisen, and Paul Bons
The Cryosphere, 19, 1153–1180, https://doi.org/10.5194/tc-19-1153-2025, https://doi.org/10.5194/tc-19-1153-2025, 2025
Short summary
Short summary
The study presents internal reflection horizons (IRHs) over an area of 450 000 km² from western Dronning Maud Land, Antarctica, spanning 4.8–91 ka. Using radar and ice core data, nine IRHs were dated and correlated with volcanic events. The data enhance our understanding of the ice sheet's age–depth architecture, accumulation, and dynamics. The findings inform ice flow models and contribute to Antarctic-wide comparisons of IRHs, supporting efforts toward a 3D age–depth ice sheet model.
Emma Pearce, Dimitri Zigone, Coen Hofstede, Andreas Fichtner, Joachim Rimpot, Sune Olander Rasmussen, Johannes Freitag, and Olaf Eisen
The Cryosphere, 18, 4917–4932, https://doi.org/10.5194/tc-18-4917-2024, https://doi.org/10.5194/tc-18-4917-2024, 2024
Short summary
Short summary
Our study near EastGRIP camp in Greenland shows varying firn properties by direction (crucial for studying ice stream stability, structure, surface mass balance, and past climate conditions). We used dispersion curve analysis of Love and Rayleigh waves to show firn is nonuniform along and across the flow of an ice stream due to wind patterns, seasonal variability, and the proximity to the edge of the ice stream. This method better informs firn structure, advancing ice stream understanding.
Julien Westhoff, Johannes Freitag, Anaïs Orsi, Patricia Martinerie, Ilka Weikusat, Michael Dyonisius, Xavier Faïn, Kevin Fourteau, and Thomas Blunier
The Cryosphere, 18, 4379–4397, https://doi.org/10.5194/tc-18-4379-2024, https://doi.org/10.5194/tc-18-4379-2024, 2024
Short summary
Short summary
We study the EastGRIP area, Greenland, in detail with traditional and novel techniques. Due to the compaction of the ice, at a certain depth, atmospheric gases can no longer exchange, and the atmosphere is trapped in air bubbles in the ice. We find this depth by pumping air from a borehole, modeling, and using a new technique based on the optical appearance of the ice. Our results suggest that the close-off depth lies at around 58–61 m depth and more precisely at 58.3 m depth.
Falk M. Oraschewski, Inka Koch, M. Reza Ershadi, Jonathan D. Hawkins, Olaf Eisen, and Reinhard Drews
The Cryosphere, 18, 3875–3889, https://doi.org/10.5194/tc-18-3875-2024, https://doi.org/10.5194/tc-18-3875-2024, 2024
Short summary
Short summary
Mountain glaciers have a layered structure which contains information about past snow accumulation and ice flow. Using ground-penetrating radar instruments, the internal structure can be observed. The detection of layers in the deeper parts of a glacier is often difficult. Here, we present a new approach for imaging the englacial structure of an Alpine glacier (Colle Gnifetti, Switzerland and Italy) using a phase-sensitive radar that can detect reflection depth changes at sub-wavelength scales.
Ole Zeising, Niklas Neckel, Nils Dörr, Veit Helm, Daniel Steinhage, Ralph Timmermann, and Angelika Humbert
The Cryosphere, 18, 1333–1357, https://doi.org/10.5194/tc-18-1333-2024, https://doi.org/10.5194/tc-18-1333-2024, 2024
Short summary
Short summary
The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier.
Anna Wendleder, Jasmin Bramboeck, Jamie Izzard, Thilo Erbertseder, Pablo d'Angelo, Andreas Schmitt, Duncan J. Quincey, Christoph Mayer, and Matthias H. Braun
The Cryosphere, 18, 1085–1103, https://doi.org/10.5194/tc-18-1085-2024, https://doi.org/10.5194/tc-18-1085-2024, 2024
Short summary
Short summary
This study analyses the basal sliding and the hydrological drainage of Baltoro Glacier, Pakistan. The surface velocity was characterized by a spring speed-up, summer peak, and autumn speed-up. Snow melt has the largest impact on the spring speed-up, summer velocity peak, and the transition from inefficient to efficient drainage. Drainage from supraglacial lakes contributed to the fall speed-up. Increased summer temperatures will intensify the magnitude of meltwater and thus surface velocities.
Ladina Steiner, Holger Schmithüsen, Jens Wickert, and Olaf Eisen
The Cryosphere, 17, 4903–4916, https://doi.org/10.5194/tc-17-4903-2023, https://doi.org/10.5194/tc-17-4903-2023, 2023
Short summary
Short summary
The present study illustrates the potential of a combined Global Navigation Satellite System reflectometry and refractometry (GNSS-RR) method for accurate, simultaneous, and continuous estimation of in situ snow accumulation, snow water equivalent, and snow density time series. The combined GNSS-RR method was successfully applied on a fast-moving, polar ice shelf. The combined GNSS-RR approach could be highly advantageous for a continuous quantification of ice sheet surface mass balances.
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
Short summary
Short summary
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
Short summary
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.
Fanny Brun, Owen King, Marion Réveillet, Charles Amory, Anton Planchot, Etienne Berthier, Amaury Dehecq, Tobias Bolch, Kévin Fourteau, Julien Brondex, Marie Dumont, Christoph Mayer, Silvan Leinss, Romain Hugonnet, and Patrick Wagnon
The Cryosphere, 17, 3251–3268, https://doi.org/10.5194/tc-17-3251-2023, https://doi.org/10.5194/tc-17-3251-2023, 2023
Short summary
Short summary
The South Col Glacier is a small body of ice and snow located on the southern ridge of Mt. Everest. A recent study proposed that South Col Glacier is rapidly losing mass. In this study, we examined the glacier thickness change for the period 1984–2017 and found no thickness change. To reconcile these results, we investigate wind erosion and surface energy and mass balance and find that melt is unlikely a dominant process, contrary to previous findings.
Alice C. Frémand, Peter Fretwell, Julien A. Bodart, Hamish D. Pritchard, Alan Aitken, Jonathan L. Bamber, Robin Bell, Cesidio Bianchi, Robert G. Bingham, Donald D. Blankenship, Gino Casassa, Ginny Catania, Knut Christianson, Howard Conway, Hugh F. J. Corr, Xiangbin Cui, Detlef Damaske, Volkmar Damm, Reinhard Drews, Graeme Eagles, Olaf Eisen, Hannes Eisermann, Fausto Ferraccioli, Elena Field, René Forsberg, Steven Franke, Shuji Fujita, Yonggyu Gim, Vikram Goel, Siva Prasad Gogineni, Jamin Greenbaum, Benjamin Hills, Richard C. A. Hindmarsh, Andrew O. Hoffman, Per Holmlund, Nicholas Holschuh, John W. Holt, Annika N. Horlings, Angelika Humbert, Robert W. Jacobel, Daniela Jansen, Adrian Jenkins, Wilfried Jokat, Tom Jordan, Edward King, Jack Kohler, William Krabill, Mette Kusk Gillespie, Kirsty Langley, Joohan Lee, German Leitchenkov, Carlton Leuschen, Bruce Luyendyk, Joseph MacGregor, Emma MacKie, Kenichi Matsuoka, Mathieu Morlighem, Jérémie Mouginot, Frank O. Nitsche, Yoshifumi Nogi, Ole A. Nost, John Paden, Frank Pattyn, Sergey V. Popov, Eric Rignot, David M. Rippin, Andrés Rivera, Jason Roberts, Neil Ross, Anotonia Ruppel, Dustin M. Schroeder, Martin J. Siegert, Andrew M. Smith, Daniel Steinhage, Michael Studinger, Bo Sun, Ignazio Tabacco, Kirsty Tinto, Stefano Urbini, David Vaughan, Brian C. Welch, Douglas S. Wilson, Duncan A. Young, and Achille Zirizzotti
Earth Syst. Sci. Data, 15, 2695–2710, https://doi.org/10.5194/essd-15-2695-2023, https://doi.org/10.5194/essd-15-2695-2023, 2023
Short summary
Short summary
This paper presents the release of over 60 years of ice thickness, bed elevation, and surface elevation data acquired over Antarctica by the international community. These data are a crucial component of the Antarctic Bedmap initiative which aims to produce a new map and datasets of Antarctic ice thickness and bed topography for the international glaciology and geophysical community.
Nicolas Stoll, Julien Westhoff, Pascal Bohleber, Anders Svensson, Dorthe Dahl-Jensen, Carlo Barbante, and Ilka Weikusat
The Cryosphere, 17, 2021–2043, https://doi.org/10.5194/tc-17-2021-2023, https://doi.org/10.5194/tc-17-2021-2023, 2023
Short summary
Short summary
Impurities in polar ice play a role regarding its climate signal and internal deformation. We bridge different scales using different methods to investigate ice from the Last Glacial Period derived from the EGRIP ice core in Greenland. We characterise different types of cloudy bands, i.e. frequently occurring milky layers in the ice, and analyse their chemistry with Raman spectroscopy and 2D imaging. We derive new insights into impurity localisation and deposition conditions.
Lena Katharina Schmidt, Till Francke, Peter Martin Grosse, Christoph Mayer, and Axel Bronstert
Hydrol. Earth Syst. Sci., 27, 1841–1863, https://doi.org/10.5194/hess-27-1841-2023, https://doi.org/10.5194/hess-27-1841-2023, 2023
Short summary
Short summary
We present a suitable method to reconstruct sediment export from decadal records of hydroclimatic predictors (discharge, precipitation, temperature) and shorter suspended sediment measurements. This lets us fill the knowledge gap on how sediment export from glacierized high-alpine areas has responded to climate change. We find positive trends in sediment export from the two investigated nested catchments with step-like increases around 1981 which are linked to crucial changes in glacier melt.
Ole Zeising, Tamara Annina Gerber, Olaf Eisen, M. Reza Ershadi, Nicolas Stoll, Ilka Weikusat, and Angelika Humbert
The Cryosphere, 17, 1097–1105, https://doi.org/10.5194/tc-17-1097-2023, https://doi.org/10.5194/tc-17-1097-2023, 2023
Short summary
Short summary
The flow of glaciers and ice streams is influenced by crystal fabric orientation. Besides sparse ice cores, these can be investigated by radar measurements. Here, we present an improved method which allows us to infer the horizontal fabric asymmetry using polarimetric phase-sensitive radar data. A validation of the method on a deep ice core from the Greenland Ice Sheet shows an excellent agreement, which is a large improvement over previously used methods.
Julian Gutt, Stefanie Arndt, David Keith Alan Barnes, Horst Bornemann, Thomas Brey, Olaf Eisen, Hauke Flores, Huw Griffiths, Christian Haas, Stefan Hain, Tore Hattermann, Christoph Held, Mario Hoppema, Enrique Isla, Markus Janout, Céline Le Bohec, Heike Link, Felix Christopher Mark, Sebastien Moreau, Scarlett Trimborn, Ilse van Opzeeland, Hans-Otto Pörtner, Fokje Schaafsma, Katharina Teschke, Sandra Tippenhauer, Anton Van de Putte, Mia Wege, Daniel Zitterbart, and Dieter Piepenburg
Biogeosciences, 19, 5313–5342, https://doi.org/10.5194/bg-19-5313-2022, https://doi.org/10.5194/bg-19-5313-2022, 2022
Short summary
Short summary
Long-term ecological observations are key to assess, understand and predict impacts of environmental change on biotas. We present a multidisciplinary framework for such largely lacking investigations in the East Antarctic Southern Ocean, combined with case studies, experimental and modelling work. As climate change is still minor here but is projected to start soon, the timely implementation of this framework provides the unique opportunity to document its ecological impacts from the very onset.
Vjeran Višnjević, Reinhard Drews, Clemens Schannwell, Inka Koch, Steven Franke, Daniela Jansen, and Olaf Eisen
The Cryosphere, 16, 4763–4777, https://doi.org/10.5194/tc-16-4763-2022, https://doi.org/10.5194/tc-16-4763-2022, 2022
Short summary
Short summary
We present a simple way to model the internal layers of an ice shelf and apply the method to the Roi Baudouin Ice Shelf in East Antarctica. Modeled results are compared to measurements obtained by radar. We distinguish between ice directly formed on the shelf and ice transported from the ice sheet, and we map the spatial changes in the volume of the locally accumulated ice. In this context, we discuss the sensitivity of the ice shelf to future changes in surface accumulation and basal melt.
Angelika Humbert, Julia Christmann, Hugh F. J. Corr, Veit Helm, Lea-Sophie Höyns, Coen Hofstede, Ralf Müller, Niklas Neckel, Keith W. Nicholls, Timm Schultz, Daniel Steinhage, Michael Wolovick, and Ole Zeising
The Cryosphere, 16, 4107–4139, https://doi.org/10.5194/tc-16-4107-2022, https://doi.org/10.5194/tc-16-4107-2022, 2022
Short summary
Short summary
Ice shelves are normally flat structures that fringe the Antarctic continent. At some locations they have channels incised into their underside. On Filchner Ice Shelf, such a channel is more than 50 km long and up to 330 m high. We conducted field measurements of basal melt rates and found a maximum of 2 m yr−1. Simulations represent the geometry evolution of the channel reasonably well. There is no reason to assume that this type of melt channel is destabilizing ice shelves.
Astrid Oetting, Emma C. Smith, Jan Erik Arndt, Boris Dorschel, Reinhard Drews, Todd A. Ehlers, Christoph Gaedicke, Coen Hofstede, Johann P. Klages, Gerhard Kuhn, Astrid Lambrecht, Andreas Läufer, Christoph Mayer, Ralf Tiedemann, Frank Wilhelms, and Olaf Eisen
The Cryosphere, 16, 2051–2066, https://doi.org/10.5194/tc-16-2051-2022, https://doi.org/10.5194/tc-16-2051-2022, 2022
Short summary
Short summary
This study combines a variety of geophysical measurements in front of and beneath the Ekström Ice Shelf in order to identify and interpret geomorphological evidences of past ice sheet flow, extent and retreat.
The maximal extent of grounded ice in this region was 11 km away from the continental shelf break.
The thickness of palaeo-ice on the calving front around the LGM was estimated to be at least 305 to 320 m.
We provide essential boundary conditions for palaeo-ice-sheet models.
Maria-Gema Llorens, Albert Griera, Paul D. Bons, Ilka Weikusat, David J. Prior, Enrique Gomez-Rivas, Tamara de Riese, Ivone Jimenez-Munt, Daniel García-Castellanos, and Ricardo A. Lebensohn
The Cryosphere, 16, 2009–2024, https://doi.org/10.5194/tc-16-2009-2022, https://doi.org/10.5194/tc-16-2009-2022, 2022
Short summary
Short summary
Polar ice is formed by ice crystals, which form fabrics that are utilised to interpret how ice sheets flow. It is unclear whether fabrics result from the current flow regime or if they are inherited. To understand the extent to which ice crystals can be reoriented when ice flow conditions change, we simulate and evaluate multi-stage ice flow scenarios according to natural cases. We find that second deformation regimes normally overprint inherited fabrics, with a range of transitional fabrics.
Julien Westhoff, Giulia Sinnl, Anders Svensson, Johannes Freitag, Helle Astrid Kjær, Paul Vallelonga, Bo Vinther, Sepp Kipfstuhl, Dorthe Dahl-Jensen, and Ilka Weikusat
Clim. Past, 18, 1011–1034, https://doi.org/10.5194/cp-18-1011-2022, https://doi.org/10.5194/cp-18-1011-2022, 2022
Short summary
Short summary
We present a melt event record from an ice core from central Greenland, which covers the past 10 000 years. Our record displays warm summer events, which can be used to enhance our understanding of the past climate. We compare our data to anomalies in tree ring width, which also represents summer temperatures, and find a good correlation. Furthermore, we investigate an outstandingly warm event in the year 986 AD or 991 AD, which has not been analyzed before.
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
Short summary
Short summary
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.
Ole Zeising, Daniel Steinhage, Keith W. Nicholls, Hugh F. J. Corr, Craig L. Stewart, and Angelika Humbert
The Cryosphere, 16, 1469–1482, https://doi.org/10.5194/tc-16-1469-2022, https://doi.org/10.5194/tc-16-1469-2022, 2022
Short summary
Short summary
Remote-sensing-derived basal melt rates of ice shelves are of great importance due to their capability to cover larger areas. We performed in situ measurements with a phase-sensitive radar on the southern Filchner Ice Shelf, showing moderate melt rates and low small-scale spatial variability. The comparison with remote-sensing-based melt rates revealed large differences caused by the estimation of vertical strain rates from remote sensing velocity fields that modern fields can overcome.
Nicolas Stoll, Maria Hörhold, Tobias Erhardt, Jan Eichler, Camilla Jensen, and Ilka Weikusat
The Cryosphere, 16, 667–688, https://doi.org/10.5194/tc-16-667-2022, https://doi.org/10.5194/tc-16-667-2022, 2022
Short summary
Short summary
We mapped and analysed solid inclusion in the upper 1340 m of the EGRIP ice core with Raman spectroscopy and microstructure mapping, based on bulk dust content derived via continuous flow analysis. We observe a large variety in mineralogy throughout the core and samples. The main minerals are sulfates, especially gypsum, and terrestrial dust minerals, such as quartz, mica, and feldspar. A change in mineralogy occurs around 900 m depth indicating a climate-related imprint.
Steven Franke, Daniela Jansen, Tobias Binder, John D. Paden, Nils Dörr, Tamara A. Gerber, Heinrich Miller, Dorthe Dahl-Jensen, Veit Helm, Daniel Steinhage, Ilka Weikusat, Frank Wilhelms, and Olaf Eisen
Earth Syst. Sci. Data, 14, 763–779, https://doi.org/10.5194/essd-14-763-2022, https://doi.org/10.5194/essd-14-763-2022, 2022
Short summary
Short summary
The Northeast Greenland Ice Stream (NEGIS) is the largest ice stream in Greenland. In order to better understand the past and future dynamics of the NEGIS, we present a high-resolution airborne radar data set (EGRIP-NOR-2018) for the onset region of the NEGIS. The survey area is centered at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP), and radar profiles cover both shear margins and are aligned parallel to several flow lines.
Nicolas Stoll, Jan Eichler, Maria Hörhold, Tobias Erhardt, Camilla Jensen, and Ilka Weikusat
The Cryosphere, 15, 5717–5737, https://doi.org/10.5194/tc-15-5717-2021, https://doi.org/10.5194/tc-15-5717-2021, 2021
Short summary
Short summary
We did a systematic analysis of the location of inclusions in the EGRIP ice core, the first ice core from an ice stream. We combine this with crystal orientation and grain size data, enabling the first overview about the microstructure of this unique ice core. Micro-inclusions show a strong spatial variability and patterns (clusters or horizontal layers); roughly one-third is located at grain boundaries. More holistic approaches are needed to understand deformation processes in the ice better.
Johannes Sutter, Hubertus Fischer, and Olaf Eisen
The Cryosphere, 15, 3839–3860, https://doi.org/10.5194/tc-15-3839-2021, https://doi.org/10.5194/tc-15-3839-2021, 2021
Short summary
Short summary
Projections of global sea-level changes in a warming world require ice-sheet models. We expand the calibration of these models by making use of the internal architecture of the Antarctic ice sheet, which is formed by its evolution over many millennia. We propose that using our novel approach to constrain ice sheet models, we will be able to both sharpen our understanding of past and future sea-level changes and identify weaknesses in the parameterisation of current continental-scale models.
Joschka Geissler, Christoph Mayer, Juilson Jubanski, Ulrich Münzer, and Florian Siegert
The Cryosphere, 15, 3699–3717, https://doi.org/10.5194/tc-15-3699-2021, https://doi.org/10.5194/tc-15-3699-2021, 2021
Short summary
Short summary
The study demonstrates the potential of photogrammetry for analyzing glacier retreat with high spatial resolution. Twenty-three glaciers within the Ötztal Alps are analyzed. We compare photogrammetric and glaciologic mass balances of the Vernagtferner by using the ELA for our density assumption and an UAV survey for a temporal correction of the geodetic mass balances. The results reveal regions of anomalous mass balance and allow estimates of the imbalance between mass balances and ice dynamics.
Sebastian Hellmann, Melchior Grab, Johanna Kerch, Henning Löwe, Andreas Bauder, Ilka Weikusat, and Hansruedi Maurer
The Cryosphere, 15, 3507–3521, https://doi.org/10.5194/tc-15-3507-2021, https://doi.org/10.5194/tc-15-3507-2021, 2021
Short summary
Short summary
In this study, we analyse whether ultrasonic measurements on ice core samples could be employed to derive information about the particular ice crystal orientation in these samples. We discuss if such ultrasonic scans of ice core samples could provide similarly detailed results as the established methods, which usually destroy the ice samples. Our geophysical approach is minimally invasive and could support the existing methods with additional and (semi-)continuous data points along the ice core.
Lukas Müller, Martin Horwath, Mirko Scheinert, Christoph Mayer, Benjamin Ebermann, Dana Floricioiu, Lukas Krieger, Ralf Rosenau, and Saurabh Vijay
The Cryosphere, 15, 3355–3375, https://doi.org/10.5194/tc-15-3355-2021, https://doi.org/10.5194/tc-15-3355-2021, 2021
Short summary
Short summary
Harald Moltke Bræ, a marine-terminating glacier in north-western Greenland, undergoes remarkable surges of episodic character. Our data show that a recent surge from 2013 to 2019 was initiated at the glacier front and exhibits a pronounced seasonality with flow velocities varying by 1 order of magnitude, which has not been observed at Harald Moltke Bræ in this way before. These findings are crucial for understanding surge mechanisms at Harald Moltke Bræ and other marine-terminating glaciers.
Cited articles
Aki, K. and Richards, P. G.: Quantitative Seismology, University Science Books Sausalito, California, 2002.
Bass, R., Rossberg, D., and Ziegler, G.: Die elastischen konstanten des Eises, Zeitschr. f. Physik, 149, 199–203, 1957.
Bennett, H. F.: An investigation into velocity anisotropy through measurements of ultrasonic wave velocities in snow and ice cores from Greenland and Antarctica, PhD thesis, University of Wisconsin-Madison, 1968.
Bentley, C. R.: Seismic wave velocities in anisotropic ice: A comparison of measured and calculated values in and around the deep drill hole at Byrd Station, Antarctica, J. Geophys. Res., 77, 4406–4420, 1972.
Binder, T.: Measurements of grain boundary networks in deep polar ice cores-A digital image processing approach, PhD thesis, Ruperto-Carola University Heidelberg, Germany, 2014.
Brockamp, B. and Querfurth, H.: Untersuchungen über die Elastizitätskonstanten von See- und Kunsteis, Polarfoschung, 34, 253–262, 1964.
Cuffey, K. M. and Paterson, W. S. B.: The Physics of Glaciers, Elsevier, Butterworth-Heineman, Amsterdam, 4th Edn., 2010.
Dahl-Jensen, D., Gogineni, S., and Panton, C.: Disturbed basal ice seen in radio echo images coincide with zones of big interlocking ice crystals, Geophys. Res. Abstr., 16, EGU2014–9677, 2014.
Daley, P. F. and Krebes, E. S.: Alternative linearized expressions for qP, qS1 and qS2 phase velocities in a weakly anisotropic orthorhombic medium, CREWES Research Report, 16, 1–19, 2004.
Dantl, G.: Die elastischen Moduln von Eis-Einkristallen, Phys. Kondens. Materie, 7, 390–397, 1968.
Diez, A. and Eisen, O.: Seismic wave propagation in anisotropic ice – Part 1: Elasticity tensor and derived quantities from ice-core properties, The Cryosphere, 9, 367–384, https://doi.org/10.5194/tc-9-367-2015, 2015.
Drews, R., Eisen, O., Weikusat, I., Kipfstuhl, S., Lambrecht, A., Steinhage, D., Wilhelms, F., and Miller, H.: Layer disturbances and the radio-echo free zone in ice sheets, The Cryosphere, 3, 195–203, https://doi.org/10.5194/tc-3-195-2009, 2009.
Drews, R., Martin, C., Steinhage, D., and Eisen, O.: Characterizing the glaciological conditions at Halvfarryggen ice dome, Dronning Maud Land, Antarctica, J. Glaciol., 59, 9–20, 2013.
Eisen, O., Wilhelms, F., Steinhage, D., and Schwander, J.: Instruments and Methods: Improved method to determine radio-echo sonding reflector depth from ice-core profiles of permittivity and conductivity, J. Glaciol., 52, 299–310, 2006.
Eisen, O., Hamann, I., Kipfstuhl, S., Steinhage, D., and Wilhelms, F.: Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric, The Cryosphere, 1, 1–10, https://doi.org/10.5194/tc-1-1-2007, 2007.
Eisen, O., Hofstede, C., Diez, A., Kristoffersen, Y., Lambrecht, A., Mayer, C., Blenkner, R., and Hilmarsson, S.: On-ice vibroseis and snowstreamer systems for geoscientific research, Polar Sci., https://doi.org/10.1016/j.polar.2014.10.003, in press, 2014.
Faria, S. H., Weikusat, I., and Azuma, N.: The microstructure of polar ice. Part II: State of the art, J. Struct. Geol., 61, 21–49, 2014.
Fischer, H., Severinghaus, J., Brook, E., Wolff, E., Albert, M., Alemany, O., Arthern, R., Bentley, C., Blankenship, D., Chappellaz, J., Creyts, T., Dahl-Jensen, D., Dinn, M., Frezzotti, M., Fujita, S., Gallee, H., Hindmarsh, R., Hudspeth, D., Jugie, G., Kawamura, K., Lipenkov, V., Miller, H., Mulvaney, R., Parrenin, F., Pattyn, F., Ritz, C., Schwander, J., Steinhage, D., van Ommen, T., and Wilhelms, F.: Where to find 1.5 million yr old ice for the IPICS "Oldest-Ice" ice core, Clim. Past, 9, 2489–2505, https://doi.org/10.5194/cp-9-2489-2013, 2013.
Fujita, S., Matsuoka, T., Ishida, T., Matsuoka, K., and Mae, S.: A summary of the complex dielectric permittivity of ice in the megahertz range and its application for radar sounding of polar ice sheets, in: The physics of ice core records, edited by: Hondoh, T., 185–212, Hokkaido University Press, 2000.
Gammon, P. H., Kiefte, H., Clouter, M. J., and Denner, W. W.: Elastic constant of artificial and natural ice samples by brillouin spectroscopy, J. Glaciol., 29, 433–460, 1983.
Gow, A. J. and Meese, D.: Physical properties, crystalline textures and c-axis fabrics of the Siple Dome (Antarctica) ice core, J. Glaciol., 53, 573–584, 2007.
Green, R. E. and Mackinnen, L.: Determination of the Elastic Constrants of Ice Single Crystals by an Ultrasonic Pulse Method, J. Acoust. Soc. Am., 28, p. 1292, https://doi.org/10.1121/1.1908626, 1956.
Gusmeroli, A., Pettit, E. C., Kennedy, J. H., and Ritz, C.: The crystal fabric of ice from full-waveform borehole sonic logging, J. Geophys. Res., 117, F03021, https://doi.org/10.1029/2012JF002343, 2012.
Hamann, I., Kipfstuhl, S., and Lambrecht, A.: Fabrics and grain-shape orientations in EDML ice core, Antarctica, in: The 28th NIPR Symposium on Polar Meteorology and Glaciology, 30 November–1 Dezember, 2005 National Institute of Polar Research, Tokyo, Japan, 2005.
Jona, F. and Scherrer, P.: Die elastischen Konstanten von Eis-Einkristallen, Helvetica Phys. Act., 25, 35–54, 1952.
Kohnen, H.: The temperature dependence of seismic waves in ice, J. Glaciol., 13, 144–147, 1974.
Matsuoka, T., Fujita, S., Morishima, S., and Mae, S.: Precise measurement of dielectric anisotropy in ice Ih at 39 GHz, J. Appl. Phys., 81, 2344–2348, 1997.
NEEM community members: Eemian interglacial reconstructed from a Greenland folded ice core, Nature, 493, 489–494, 2013.
Oerter, H., Drücker, C., Kipfstuhl, S., and Wilhelms, F.: Kohnen Station–the Drilling Camp for the EPICA Deep Ice Core in Dronning Maud Land, Polarforschung, 78, 1–23, 2009.
Penny, A. H. A.: A theoretical determination of the elastic constants of ice, Math. Proc. Cambridge Philosoph. Soc., 44, 423–439, 1948.
Ross, N. and Siegert, M.: Concentrated englacial shear over rigid basal ice, West Antarctica: implications for modelling and ice sheet flow, Geophys. Res. Abstr., 16, EGU2014–5568, 2014.
Svensson, A., Bigler, M., Blunier, T., Clausen, H. B., Dahl-Jensen, D., Fischer, H., Fujita, S., Goto-Azuma, K., Johnsen, S. J., Kawamura, K., Kipfstuhl, S., Kohno, M., Parrenin, F., Popp, T., Rasmussen, S. O., Schwander, J., Seierstad, I., Severi, M., Steffensen, J. P., Udisti, R., Uemura, R., Vallelonga, P., Vinther, B. M., Wegner, A., Wilhelms, F., and Winstrup, M.: Direct linking of Greenland and Antarctic ice cores at the Toba eruption (74 ka BP), Clim. Past, 9, 749–766, https://doi.org/10.5194/cp-9-749-2013, 2013.
Weikusat, I., Kipfstuhl, S., Faria, S. H., Azuma, N., and Miyamoto, A.: Subgrain boundaries and related microstructural features in EDML (Antarctica) deep ice core, J. Glaciol., 55, 461–472, 2009.
Wilhelms, F., Sheldon, S. G., Hamann, I., and Kipfstuhl, S.: Implications for and findings from deep ice core drillings an example: The ultimate tensile strength of ice at high strain rates, Physics and Chemistry of Ice (The proceedings of the International Conference on the Physics and Chemistry of Ice held at Bremerhaven, Germany on 23–28 July 2006) The Royal Society of Chemistry Special Publication No. 311, 635–639, 2007.
