Articles | Volume 8, issue 4
https://doi.org/10.5194/tc-8-1129-2014
© Author(s) 2014. 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-8-1129-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
01 Jul 2014
Research article |
| 01 Jul 2014
Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores
M. Montagnat
CNRS, LGGE, UMR5183, 38041 Grenoble, France
Univ. Grenoble Alpes, LGGE, 38041 Grenoble, France
N. Azuma
Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata, Japan
D. Dahl-Jensen
Niels Bohr Institute, Ice and Climate Research, University of Copenhagen, Juliane Maries Vej 30,
2100 Copenhagen, Denmark
2100 Copenhagen, Denmark
J. Eichler
Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, Germany
Fachbereich Physik, Freie Universitat Berlin, Arnimallee 14, 14195 Berlin, Germany
S. Fujita
National Institute of Polar Research, Research Organization of Information and Systems (ROIS), Midori-chou 10-3, Tachikawa, Tokyo, 190-8518, Japan
F. Gillet-Chaulet
CNRS, LGGE, UMR5183, 38041 Grenoble, France
Univ. Grenoble Alpes, LGGE, 38041 Grenoble, France
S. Kipfstuhl
Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, Germany
D. Samyn
Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka 940-2188, Niigata, Japan
A. Svensson
Niels Bohr Institute, Ice and Climate Research, University of Copenhagen, Juliane Maries Vej 30,
2100 Copenhagen, Denmark
2100 Copenhagen, Denmark
I. Weikusat
Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, 27568 Bremerhaven, Germany
Related authors
Baptiste Journaux, Thomas Chauve, Maurine Montagnat, Andrea Tommasi, Fabrice Barou, David Mainprice, and Léa Gest
The Cryosphere, 13, 1495–1511, https://doi.org/10.5194/tc-13-1495-2019, https://doi.org/10.5194/tc-13-1495-2019, 2019
Short summary
Short summary
Ice mechanics is an important tool to better predict the response of glaciers or polar ice sheets to climate variations.
Nevertheless our current predictive abilities are limited as the microscale mechanisms responsible for ice creep are poorly identified.
We show in this study, using state-of-the-art experimental techniques, which recrystallization processes control ice deformation. This will allow realistic simulations, necessary to predict the long-term effects on ice landmasses.
Jilu Li, Jose A. Vélez González, Carl Leuschen, Ayyangar Harish, Prasad Gogineni, Maurine Montagnat, Ilka Weikusat, Fernando Rodriguez-Morales, and John Paden
The Cryosphere, 12, 2689–2705, https://doi.org/10.5194/tc-12-2689-2018, https://doi.org/10.5194/tc-12-2689-2018, 2018
Short summary
Short summary
Ice properties inferred from multi-polarization measurements can provide insight into ice strain, viscosity, and ice flow. The Center for Remote Sensing of Ice Sheets used a ground-based radar for multi-channel and multi-polarization measurements at the NEEM site. This paper describes the radar system, antenna configurations, data collection, and processing and analysis of this data set. Comparisons between the radar observations, simulations, and ice core fabric data are in very good agreement.
Thomas Chauve, Maurine Montagnat, Cedric Lachaud, David Georges, and Pierre Vacher
Solid Earth, 8, 943–953, https://doi.org/10.5194/se-8-943-2017, https://doi.org/10.5194/se-8-943-2017, 2017
Short summary
Short summary
For the first time, digital image correlation was used to follow strain field development and evolution during micro-cracking, at the ductile-to-brittle transition in polycrystalline ice.
Owing to the high-temperature conditions of the tests, dynamic recrystallization mechanisms (nucleation and sub-grain rotation) efficiently participate in the stress redistribution during and after crack opening, and even lead to local crack closure.
Agnès Maurel, Jean-François Mercier, and Maurine Montagnat
The Cryosphere, 10, 3063–3070, https://doi.org/10.5194/tc-10-3063-2016, https://doi.org/10.5194/tc-10-3063-2016, 2016
Short summary
Short summary
Crystallographic texture evolution with depth along ice cores can be evaluated using borehole sonic logging measurements. These measurements provide the velocities of elastic waves that depend on the ice polycrystal anisotropy and can further be related to the ice texture. To do so, elastic velocities need to be inverted from a modeling approach that relate elastic velocities to ice texture. The present paper presents a critical analysis of the different methods used for the inversion.
Tomotaka Saruya, Atsushi Miyamoto, Shuji Fujita, Kumiko Goto-Azuma, Motohiro Hirabayashi, Akira Hori, Makoto Igarashi, Yoshinori Iizuka, Takao Kameda, Hiroshi Ohno, Wataru Shigeyama, and Shun Tsutaki
The Cryosphere, 19, 2365–2385, https://doi.org/10.5194/tc-19-2365-2025, https://doi.org/10.5194/tc-19-2365-2025, 2025
Short summary
Short summary
Crystal orientation fabrics and microstructures in the deep sections of the Dome Fuji (DF) ice core were investigated using innovative methods with dense depth coverage. Together with our previous studies, we have obtained whole layer profiles of the crystal orientation fabric and physical properties of the DF ice core. Development and fluctuation of the crystal orientation fabric were found to be highly dependent on impurity concentrations and recrystallization processes.
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.
Florian Painer, Sepp Kipfstuhl, Martyn Drury, Tsutomu Uchida, Johannes Freitag, and Ilka Weikusat
EGUsphere, https://doi.org/10.5194/egusphere-2025-633, https://doi.org/10.5194/egusphere-2025-633, 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 to better understand air clathrate hydrates in deep ice.
Paul Dirk Bons, Yuanbang Hu, Maria-Gema Llorens, Steven Franke, Nicolas Stoll, Ilka Weikusat, Julien Wetshoff, and Yu Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2024-3817, https://doi.org/10.5194/egusphere-2024-3817, 2025
Short summary
Short summary
What causes folds in ice layers from the km-scale down to the scale visible in drill core? Classical 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? Comparison of power spectra of folds in ice, a biotite schist, and numerical simulations show that folding in ice is due to the mechanical anisotropy, as there is no characteristic fold scale that would result from buckle folding.
Margaret Mallory Harlan, Jodi Fox, Helle Astrid Kjær, Tessa R. Vance, Anders Svensson, and Eliza Cook
Clim. Past Discuss., https://doi.org/10.5194/cp-2024-64, https://doi.org/10.5194/cp-2024-64, 2024
Revised manuscript under review for CP
Short summary
Short summary
We identify two tephra horizons in the Mount Brown South (MBS) ice core originating from the mid-1980s eruptive period of Mt. Erebus and the 1991 eruption of Cerro Hudson. They represent an important addition to East Antarctic tephrochronology, with implications for understanding atmospheric dynamics and ice core chronologies. This work underpins the importance of the MBS ice core as a new tephrochronological archive in an underrepresented region of coastal East Antarctica.
Margaret Harlan, Helle Astrid Kjær, Aylin de Campo, Anders Svensson, Thomas Blunier, Vasileios Gkinis, Sarah Jackson, Christopher Plummer, and Tessa Vance
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2024-335, https://doi.org/10.5194/essd-2024-335, 2024
Revised manuscript under review for ESSD
Short summary
Short summary
This paper provides high-resolution chemistry and impurity measurements from the Mount Brown South ice core in East Antarctica, from 873 to 2009 CE. Measurements include sodium, ammonium, hydrogen peroxide, electrolytic conductivity, and insoluble microparticles. Data are provided on three scales: 1 mm and 3 cm averaged depth resolution and decadally averaged. The paper also describes the continuous flow analysis systems used to collect the data as well as uncertainties and data quality.
Nicolas Stoll, Ilka Weikusat, Daniela Jansen, Paul Bons, Kyra Darányi, Julien Westhoff, Mária-Gema Llorens, David Wallis, Jan Eichler, Tomotaka Saruya, Tomoyuki Homma, Martyn Drury, Frank Wilhelms, Sepp Kipfstuhl, Dorthe Dahl-Jensen, and Johanna Kerch
EGUsphere, https://doi.org/10.5194/egusphere-2024-2653, https://doi.org/10.5194/egusphere-2024-2653, 2024
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 to determine the present deformation regimes. A comparison with other deep ice cores shows the unique properties of EastGRIP and that deep ice 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.
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.
Ryo Inoue, Teruo Aoki, Shuji Fujita, Shun Tsutaki, Hideaki Motoyama, Fumio Nakazawa, and Kenji Kawamura
The Cryosphere, 18, 3513–3531, https://doi.org/10.5194/tc-18-3513-2024, https://doi.org/10.5194/tc-18-3513-2024, 2024
Short summary
Short summary
We measured the snow specific surface area (SSA) at ~2150 surfaces between the coast near Syowa Station and Dome Fuji, East Antarctica, in summer 2021–2022. The observed SSA shows no elevation dependence between 15 and 500 km from the coast and increases toward the dome area beyond the range. SSA varies depending on surface morphologies and meteorological events. The spatial variation of SSA can be explained by snow metamorphism, snowfall frequency, and wind-driven inhibition of snow deposition.
Johannes Lohmann, Jiamei Lin, Bo M. Vinther, Sune O. Rasmussen, and Anders Svensson
Clim. Past, 20, 313–333, https://doi.org/10.5194/cp-20-313-2024, https://doi.org/10.5194/cp-20-313-2024, 2024
Short summary
Short summary
We present the first attempt to constrain the climatic impact of volcanic eruptions with return periods of hundreds of years by the oxygen isotope records of Greenland and Antarctic ice cores covering the last glacial period. A clear multi-annual volcanic cooling signal is seen, but its absolute magnitude is subject to the unknown glacial sensitivity of the proxy. Different proxy signals after eruptions during cooler versus warmer glacial stages may reflect a state-dependent climate response.
Ryo Inoue, Shuji Fujita, Kenji Kawamura, Ikumi Oyabu, Fumio Nakazawa, Hideaki Motoyama, and Teruo Aoki
The Cryosphere, 18, 425–449, https://doi.org/10.5194/tc-18-425-2024, https://doi.org/10.5194/tc-18-425-2024, 2024
Short summary
Short summary
We measured the density, microstructural anisotropy, and specific surface area (SSA) of six firn cores collected within 60 km of Dome Fuji, Antarctica. We found a lack of significant density increase, development of vertically elongated microstructures, and a rapid decrease in SSA in the top few meters due to the metamorphism driven by water vapor transport under a temperature gradient. We highlight the significant spatial variability in the properties, which depends on the accumulation rate.
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
Short summary
Short summary
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.
Sune Olander Rasmussen, Dorthe Dahl-Jensen, Hubertus Fischer, Katrin Fuhrer, Steffen Bo Hansen, Margareta Hansson, Christine S. Hvidberg, Ulf Jonsell, Sepp Kipfstuhl, Urs Ruth, Jakob Schwander, Marie-Louise Siggaard-Andersen, Giulia Sinnl, Jørgen Peder Steffensen, Anders M. Svensson, and Bo M. Vinther
Earth Syst. Sci. Data, 15, 3351–3364, https://doi.org/10.5194/essd-15-3351-2023, https://doi.org/10.5194/essd-15-3351-2023, 2023
Short summary
Short summary
Timescales are essential for interpreting palaeoclimate data. The data series presented here were used for annual-layer identification when constructing the timescales named the Greenland Ice-Core Chronology 2005 (GICC05) and the revised version GICC21. Hopefully, these high-resolution data sets will be useful also for other purposes.
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.
Takashi Obase, Ayako Abe-Ouchi, Fuyuki Saito, Shun Tsutaki, Shuji Fujita, Kenji Kawamura, and Hideaki Motoyama
The Cryosphere, 17, 2543–2562, https://doi.org/10.5194/tc-17-2543-2023, https://doi.org/10.5194/tc-17-2543-2023, 2023
Short summary
Short summary
We use a one-dimensional ice-flow model to examine the most suitable core location near Dome Fuji (DF), Antarctica. This model computes the temporal evolution of age and temperature from past to present. We investigate the influence of different parameters of climate and ice sheet on the ice's basal age and compare the results with ground radar surveys. We find that the local ice thickness primarily controls the age because it is critical to the basal melting, which can eliminate the old ice.
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
Short summary
Short summary
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.
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.
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.
Niccolò Maffezzoli, Eliza Cook, Willem G. M. van der Bilt, Eivind N. Støren, Daniela Festi, Florian Muthreich, Alistair W. R. Seddon, François Burgay, Giovanni Baccolo, Amalie R. F. Mygind, Troels Petersen, Andrea Spolaor, Sebastiano Vascon, Marcello Pelillo, Patrizia Ferretti, Rafael S. dos Reis, Jefferson C. Simões, Yuval Ronen, Barbara Delmonte, Marco Viccaro, Jørgen Peder Steffensen, Dorthe Dahl-Jensen, Kerim H. Nisancioglu, and Carlo Barbante
The Cryosphere, 17, 539–565, https://doi.org/10.5194/tc-17-539-2023, https://doi.org/10.5194/tc-17-539-2023, 2023
Short summary
Short summary
Multiple lines of research in ice core science are limited by manually intensive and time-consuming optical microscopy investigations for the detection of insoluble particles, from pollen grains to volcanic shards. To help overcome these limitations and support researchers, we present a novel methodology for the identification and autonomous classification of ice core insoluble particles based on flow image microscopy and neural networks.
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
Short summary
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.
Zhiheng Du, Jiao Yang, Lei Wang, Ninglian Wang, Anders Svensson, Zhen Zhang, Xiangyu Ma, Yaping Liu, Shimeng Wang, Jianzhong Xu, and Cunde Xiao
Earth Syst. Sci. Data, 14, 5349–5365, https://doi.org/10.5194/essd-14-5349-2022, https://doi.org/10.5194/essd-14-5349-2022, 2022
Short summary
Short summary
A dataset of the radiogenic strontium and neodymium isotopic compositions from the three poles (the third pole, the Arctic, and Antarctica) were integrated to obtain new findings. The dataset enables us to map the standardized locations in the three poles, while the use of sorting criteria related to the sample type permits us to trace the dust sources and sinks. The purpose of this dataset is to try to determine the variable transport pathways of dust at three poles.
Helle Astrid Kjær, Patrick Zens, Samuel Black, Kasper Holst Lund, Anders Svensson, and Paul Vallelonga
Clim. Past, 18, 2211–2230, https://doi.org/10.5194/cp-18-2211-2022, https://doi.org/10.5194/cp-18-2211-2022, 2022
Short summary
Short summary
Six shallow cores from northern Greenland spanning a distance of 426 km were retrieved during a traversal in 2015. We identify several recent acid horizons associated with Icelandic eruptions and eruptions in the Barents Sea region and obtain a robust forest fire proxy associated primarily with Canadian forest fires. We also observe an increase in the large dust particle fluxes that we attribute to an activation of Greenland local sources in recent years (1998–2015).
Johannes Lohmann and Anders Svensson
Clim. Past, 18, 2021–2043, https://doi.org/10.5194/cp-18-2021-2022, https://doi.org/10.5194/cp-18-2021-2022, 2022
Short summary
Short summary
Major volcanic eruptions are known to cause considerable short-term impacts on the global climate. Their influence on long-term climate variability and regime shifts is less well-understood. Here we show that very large, bipolar eruptions occurred more frequently than expected by chance just before abrupt climate change events in the last glacial period (Dansgaard–Oeschger events). Thus, such large eruptions may in some cases act as short-term triggers for abrupt regime shifts of the climate.
Shun Tsutaki, Shuji Fujita, Kenji Kawamura, Ayako Abe-Ouchi, Kotaro Fukui, Hideaki Motoyama, Yu Hoshina, Fumio Nakazawa, Takashi Obase, Hiroshi Ohno, Ikumi Oyabu, Fuyuki Saito, Konosuke Sugiura, and Toshitaka Suzuki
The Cryosphere, 16, 2967–2983, https://doi.org/10.5194/tc-16-2967-2022, https://doi.org/10.5194/tc-16-2967-2022, 2022
Short summary
Short summary
We constructed an ice thickness map across the Dome Fuji region, East Antarctica, from improved radar data and previous data that had been collected since the late 1980s. The data acquired using the improved radar systems allowed basal topography to be identified with higher accuracy. The new ice thickness data show the bedrock topography, particularly the complex terrain of subglacial valleys and highlands south of Dome Fuji, with substantially high detail.
Tomotaka Saruya, Shuji Fujita, Yoshinori Iizuka, Atsushi Miyamoto, Hiroshi Ohno, Akira Hori, Wataru Shigeyama, Motohiro Hirabayashi, and Kumiko Goto-Azuma
The Cryosphere, 16, 2985–3003, https://doi.org/10.5194/tc-16-2985-2022, https://doi.org/10.5194/tc-16-2985-2022, 2022
Short summary
Short summary
Crystal orientation fabrics (COF) of the Dome Fuji ice core were investigated with an innovative method with unprecedentedly high statistical significance and dense depth coverage. The COF profile and its fluctuation were found to be highly dependent on concentrations of chloride ion and dust. The data suggest deformation of ice at the deepest zone is highly influenced by COF fluctuations that progressively develop from the near-surface firn toward the deepest zone within ice sheets.
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.
Giulia Sinnl, Mai Winstrup, Tobias Erhardt, Eliza Cook, Camilla Marie Jensen, Anders Svensson, Bo Møllesøe Vinther, Raimund Muscheler, and Sune Olander Rasmussen
Clim. Past, 18, 1125–1150, https://doi.org/10.5194/cp-18-1125-2022, https://doi.org/10.5194/cp-18-1125-2022, 2022
Short summary
Short summary
A new Greenland ice-core timescale, covering the last 3800 years, was produced using the machine learning algorithm StratiCounter. We synchronized the ice cores using volcanic eruptions and wildfires. We compared the new timescale to the tree-ring timescale, finding good alignment both between the common signatures of volcanic eruptions and of solar activity. Our Greenlandic timescales is safe to use for the Late Holocene, provided one uses our uncertainty estimate.
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.
Jiamei Lin, Anders Svensson, Christine S. Hvidberg, Johannes Lohmann, Steffen Kristiansen, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Sune Olander Rasmussen, Eliza Cook, Helle Astrid Kjær, Bo M. Vinther, Hubertus Fischer, Thomas Stocker, Michael Sigl, Matthias Bigler, Mirko Severi, Rita Traversi, and Robert Mulvaney
Clim. Past, 18, 485–506, https://doi.org/10.5194/cp-18-485-2022, https://doi.org/10.5194/cp-18-485-2022, 2022
Short summary
Short summary
We employ acidity records from Greenland and Antarctic ice cores to estimate the emission strength, frequency and climatic forcing for large volcanic eruptions from the last half of the last glacial period. A total of 25 volcanic eruptions are found to be larger than any eruption in the last 2500 years, and we identify more eruptions than obtained from geological evidence. Towards the end of the glacial period, there is a notable increase in volcanic activity observed for Greenland.
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.
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
Short summary
Short summary
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.
Helle Astrid Kjær, Lisa Lolk Hauge, Marius Simonsen, Zurine Yoldi, Iben Koldtoft, Maria Hörhold, Johannes Freitag, Sepp Kipfstuhl, Anders Svensson, and Paul Vallelonga
The Cryosphere, 15, 3719–3730, https://doi.org/10.5194/tc-15-3719-2021, https://doi.org/10.5194/tc-15-3719-2021, 2021
Short summary
Short summary
Ice core analyses are often done in home laboratories after costly transport of samples from the field. This limits the amount of sample that can be analysed.
Here, we present the first truly field-portable continuous flow analysis (CFA) system for the analysis of impurities in snow, firn and ice cores while still in the field: the lightweight in situ analysis (LISA) box.
LISA is demonstrated in Greenland to reconstruct accumulation, conductivity and peroxide in snow cores.
Tamara Annina Gerber, Christine Schøtt Hvidberg, Sune Olander Rasmussen, Steven Franke, Giulia Sinnl, Aslak Grinsted, Daniela Jansen, and Dorthe Dahl-Jensen
The Cryosphere, 15, 3655–3679, https://doi.org/10.5194/tc-15-3655-2021, https://doi.org/10.5194/tc-15-3655-2021, 2021
Short summary
Short summary
We simulate the ice flow in the onset region of the Northeast Greenland Ice Stream to determine the source area and past accumulation rates of ice found in the EastGRIP ice core. This information is required to correct for bias in ice-core records introduced by the upstream flow effects. Our results reveal that the increasing accumulation rate with increasing upstream distance is predominantly responsible for the constant annual layer thicknesses observed in the upper 900 m of the ice core.
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.
Paul D. Bons, Tamara de Riese, Steven Franke, Maria-Gema Llorens, Till Sachau, Nicolas Stoll, Ilka Weikusat, Julien Westhoff, and Yu Zhang
The Cryosphere, 15, 2251–2254, https://doi.org/10.5194/tc-15-2251-2021, https://doi.org/10.5194/tc-15-2251-2021, 2021
Short summary
Short summary
The modelling of Smith-Johnson et al. (The Cryosphere, 14, 841–854, 2020) suggests that a very large heat flux of more than 10 times the usual geothermal heat flux is required to have initiated or to control the huge Northeast Greenland Ice Stream. Our comparison with known hotspots, such as Iceland and Yellowstone, shows that such an exceptional heat flux would be unique in the world and is incompatible with known geological processes that can raise the heat flux.
David A. Lilien, Daniel Steinhage, Drew Taylor, Frédéric Parrenin, Catherine Ritz, Robert Mulvaney, Carlos Martín, Jie-Bang Yan, Charles O'Neill, Massimo Frezzotti, Heinrich Miller, Prasad Gogineni, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, https://doi.org/10.5194/tc-15-1881-2021, 2021
Short summary
Short summary
We collected radar data between EDC, an ice core spanning ~800 000 years, and BELDC, the site chosen for a new
oldest icecore at nearby Little Dome C. These data allow us to identify 50 % older internal horizons than previously traced in the area. We fit a model to the ages of those horizons at BELDC to determine the age of deep ice there. We find that there is likely to be 1.5 Myr old ice ~265 m above the bed, with sufficient resolution to preserve desired climatic information.
Sebastian Hellmann, Johanna Kerch, Ilka Weikusat, Andreas Bauder, Melchior Grab, Guillaume Jouvet, Margit Schwikowski, and Hansruedi Maurer
The Cryosphere, 15, 677–694, https://doi.org/10.5194/tc-15-677-2021, https://doi.org/10.5194/tc-15-677-2021, 2021
Short summary
Short summary
We analyse the orientation of ice crystals in an Alpine glacier and compare this orientation with the ice flow direction. We found that the crystals orient in the direction of the largest stress which is in the flow direction in the upper parts of the glacier and in the vertical direction for deeper zones of the glacier. The grains cluster around this maximum stress direction, in particular four-point maxima, most likely as a result of recrystallisation under relatively warm conditions.
Helle Astrid Kjær, Patrick Zens, Ross Edwards, Martin Olesen, Ruth Mottram, Gabriel Lewis, Christian Terkelsen Holme, Samuel Black, Kasper Holst Lund, Mikkel Schmidt, Dorthe Dahl-Jensen, Bo Vinther, Anders Svensson, Nanna Karlsson, Jason E. Box, Sepp Kipfstuhl, and Paul Vallelonga
The Cryosphere Discuss., https://doi.org/10.5194/tc-2020-337, https://doi.org/10.5194/tc-2020-337, 2021
Manuscript not accepted for further review
Short summary
Short summary
We have reconstructed accumulation in 6 firn cores and 8 snow cores in Northern Greenland and compared with a regional Climate model over Greenland. We find the model underestimate precipitation especially in north-eastern part of the ice cap- an important finding if aiming to reconstruct surface mass balance.
Temperatures at 10 meters depth at 6 sites in Greenland were also determined and show a significant warming since the 1990's of 0.9 to 2.5 °C.
Johannes Lohmann and Anders Svensson
Clim. Past Discuss., https://doi.org/10.5194/cp-2020-160, https://doi.org/10.5194/cp-2020-160, 2020
Manuscript not accepted for further review
Short summary
Short summary
Major volcanic eruptions are known to cause considerable short-term impacts on the global climate. Their influence on long-term climate variability and regime shifts is less well understood. Here we show that very large, bipolar eruptions occurred more frequently than expected by chance just before abrupt climate change events in the last glacial period (the Dansgaard-Oeschger events). Thus, such large eruptions may in some cases act as short-term triggers to abrupt regime shifts of the climate.
Ikumi Oyabu, Kenji Kawamura, Kyotaro Kitamura, Remi Dallmayr, Akihiro Kitamura, Chikako Sawada, Jeffrey P. Severinghaus, Ross Beaudette, Anaïs Orsi, Satoshi Sugawara, Shigeyuki Ishidoya, Dorthe Dahl-Jensen, Kumiko Goto-Azuma, Shuji Aoki, and Takakiyo Nakazawa
Atmos. Meas. Tech., 13, 6703–6731, https://doi.org/10.5194/amt-13-6703-2020, https://doi.org/10.5194/amt-13-6703-2020, 2020
Short summary
Short summary
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.
Seyedhamidreza Mojtabavi, Frank Wilhelms, Eliza Cook, Siwan M. Davies, Giulia Sinnl, Mathias Skov Jensen, Dorthe Dahl-Jensen, Anders Svensson, Bo M. Vinther, Sepp Kipfstuhl, Gwydion Jones, Nanna B. Karlsson, Sergio Henrique Faria, Vasileios Gkinis, Helle Astrid Kjær, Tobias Erhardt, Sarah M. P. Berben, Kerim H. Nisancioglu, Iben Koldtoft, and Sune Olander Rasmussen
Clim. Past, 16, 2359–2380, https://doi.org/10.5194/cp-16-2359-2020, https://doi.org/10.5194/cp-16-2359-2020, 2020
Short summary
Short summary
We present a first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination. After field measurements and processing of the ice-core data, the GICC05 timescale is transferred from the NGRIP core to the EGRIP core by means of matching volcanic events and common patterns (381 match points) in the ECM and DEP records. The new timescale is named GICC05-EGRIP-1 and extends back to around 15 kyr b2k.
Christine S. Hvidberg, Aslak Grinsted, Dorthe Dahl-Jensen, Shfaqat Abbas Khan, Anders Kusk, Jonas Kvist Andersen, Niklas Neckel, Anne Solgaard, Nanna B. Karlsson, Helle Astrid Kjær, and Paul Vallelonga
The Cryosphere, 14, 3487–3502, https://doi.org/10.5194/tc-14-3487-2020, https://doi.org/10.5194/tc-14-3487-2020, 2020
Short summary
Short summary
The Northeast Greenland Ice Stream (NEGIS) extends around 600 km from its onset in the interior of Greenland to the coast. Several maps of surface velocity and topography in Greenland exist, but accuracy is limited due to the lack of validation data. Here we present results from a 5-year GPS survey in an interior section of NEGIS. We use the data to assess a list of satellite-derived ice velocity and surface elevation products and discuss the implications for the ice stream flow in the area.
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
Short summary
Short summary
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
Short summary
Short summary
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.
Ernst-Jan N. Kuiper, Ilka Weikusat, Johannes H. P. de Bresser, Daniela Jansen, Gill M. Pennock, and Martyn R. Drury
The Cryosphere, 14, 2429–2448, https://doi.org/10.5194/tc-14-2429-2020, https://doi.org/10.5194/tc-14-2429-2020, 2020
Short summary
Short summary
A composite flow law model applied to crystal size distributions from the NEEM deep ice core predicts that fine-grained layers in ice from the last Glacial period localize deformation as internal shear zones in the Greenland ice sheet deforming by grain-size-sensitive creep. This prediction is consistent with microstructures in Glacial age ice.
Ernst-Jan N. Kuiper, Johannes H. P. de Bresser, Martyn R. Drury, Jan Eichler, Gill M. Pennock, and Ilka Weikusat
The Cryosphere, 14, 2449–2467, https://doi.org/10.5194/tc-14-2449-2020, https://doi.org/10.5194/tc-14-2449-2020, 2020
Short summary
Short summary
Fast ice flow occurs in deeper parts of polar ice sheets, driven by high stress and high temperatures. Above 262 K ice flow is further enhanced, probably by the formation of thin melt layers between ice crystals. A model applying an experimentally derived composite flow law, using temperature and grain size values from the deepest 540 m of the NEEM ice core, predicts that flow in fine-grained layers is enhanced by a factor of 10 compared to coarse-grained layers in the Greenland ice sheet.
Baptiste Journaux, Thomas Chauve, Maurine Montagnat, Andrea Tommasi, Fabrice Barou, David Mainprice, and Léa Gest
The Cryosphere, 13, 1495–1511, https://doi.org/10.5194/tc-13-1495-2019, https://doi.org/10.5194/tc-13-1495-2019, 2019
Short summary
Short summary
Ice mechanics is an important tool to better predict the response of glaciers or polar ice sheets to climate variations.
Nevertheless our current predictive abilities are limited as the microscale mechanisms responsible for ice creep are poorly identified.
We show in this study, using state-of-the-art experimental techniques, which recrystallization processes control ice deformation. This will allow realistic simulations, necessary to predict the long-term effects on ice landmasses.
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
Short summary
Short summary
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.
Florian Adolphi, Christopher Bronk Ramsey, Tobias Erhardt, R. Lawrence Edwards, Hai Cheng, Chris S. M. Turney, Alan Cooper, Anders Svensson, Sune O. Rasmussen, Hubertus Fischer, and Raimund Muscheler
Clim. Past, 14, 1755–1781, https://doi.org/10.5194/cp-14-1755-2018, https://doi.org/10.5194/cp-14-1755-2018, 2018
Short summary
Short summary
The last glacial period was characterized by a number of rapid climate changes seen, for example, as abrupt warmings in Greenland and changes in monsoon rainfall intensity. However, due to chronological uncertainties it is challenging to know how tightly coupled these changes were. Here we exploit cosmogenic signals caused by changes in the Sun and Earth magnetic fields to link different climate archives and improve our understanding of the dynamics of abrupt climate change.
Jilu Li, Jose A. Vélez González, Carl Leuschen, Ayyangar Harish, Prasad Gogineni, Maurine Montagnat, Ilka Weikusat, Fernando Rodriguez-Morales, and John Paden
The Cryosphere, 12, 2689–2705, https://doi.org/10.5194/tc-12-2689-2018, https://doi.org/10.5194/tc-12-2689-2018, 2018
Short summary
Short summary
Ice properties inferred from multi-polarization measurements can provide insight into ice strain, viscosity, and ice flow. The Center for Remote Sensing of Ice Sheets used a ground-based radar for multi-channel and multi-polarization measurements at the NEEM site. This paper describes the radar system, antenna configurations, data collection, and processing and analysis of this data set. Comparisons between the radar observations, simulations, and ice core fabric data are in very good agreement.
Johanna Kerch, Anja Diez, Ilka Weikusat, and Olaf Eisen
The Cryosphere, 12, 1715–1734, https://doi.org/10.5194/tc-12-1715-2018, https://doi.org/10.5194/tc-12-1715-2018, 2018
Short summary
Short summary
We investigate the effect of crystal anisotropy on seismic velocities in glacier ice by calculating seismic phase velocities using the exact c axis angles to describe the crystal orientations in ice-core samples for an alpine and a polar ice core. Our results provide uncertainty estimates for earlier established approximative calculations. Additionally, our findings highlight the variation in seismic velocity at non-vertical incidence as a function of the horizontal azimuth of the seismic plane.
Marius Folden Simonsen, Llorenç Cremonesi, Giovanni Baccolo, Samuel Bosch, Barbara Delmonte, Tobias Erhardt, Helle Astrid Kjær, Marco Potenza, Anders Svensson, and Paul Vallelonga
Clim. Past, 14, 601–608, https://doi.org/10.5194/cp-14-601-2018, https://doi.org/10.5194/cp-14-601-2018, 2018
Short summary
Short summary
Ice core dust size distributions are more often measured today by an Abakus laser sensor than by the more technically demanding but also very accurate Coulter counter. However, Abakus measurements consistently give larger particle sizes. We show here that this bias exists because the particles are flat and elongated. Correcting for this gives more accurate Abakus measurements. Furthermore, the shape of the particles can be extracted from a combination of Coulter counter and Abakus measurements.
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
Short summary
Short summary
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.
Niklas Boers, Mickael D. Chekroun, Honghu Liu, Dmitri Kondrashov, Denis-Didier Rousseau, Anders Svensson, Matthias Bigler, and Michael Ghil
Earth Syst. Dynam., 8, 1171–1190, https://doi.org/10.5194/esd-8-1171-2017, https://doi.org/10.5194/esd-8-1171-2017, 2017
Short summary
Short summary
We use a Bayesian approach for inferring inverse, stochastic–dynamic models from northern Greenland (NGRIP) oxygen and dust records of subdecadal resolution for the interval 59 to 22 ka b2k. Our model reproduces the statistical and dynamical characteristics of the records, including the Dansgaard–Oeschger variability, with no need for external forcing. The crucial ingredients are cubic drift terms, nonlinear coupling terms between the oxygen and dust time series, and non-Markovian contributions.
Denis-Didier Rousseau, Anders Svensson, Matthias Bigler, Adriana Sima, Jorgen Peder Steffensen, and Niklas Boers
Clim. Past, 13, 1181–1197, https://doi.org/10.5194/cp-13-1181-2017, https://doi.org/10.5194/cp-13-1181-2017, 2017
Short summary
Short summary
We show that the analysis of δ18O and dust in the Greenland ice cores, and a critical study of their source variations, reconciles these records with those observed on the Eurasian continent. We demonstrate the link between European and Chinese loess sequences, dust records in Greenland, and variations in the North Atlantic sea ice extent. The sources of the emitted and transported dust material are variable and relate to different environments.
Thomas Chauve, Maurine Montagnat, Cedric Lachaud, David Georges, and Pierre Vacher
Solid Earth, 8, 943–953, https://doi.org/10.5194/se-8-943-2017, https://doi.org/10.5194/se-8-943-2017, 2017
Short summary
Short summary
For the first time, digital image correlation was used to follow strain field development and evolution during micro-cracking, at the ductile-to-brittle transition in polycrystalline ice.
Owing to the high-temperature conditions of the tests, dynamic recrystallization mechanisms (nucleation and sub-grain rotation) efficiently participate in the stress redistribution during and after crack opening, and even lead to local crack closure.
Ilka Weikusat, Ernst-Jan N. Kuiper, Gill M. Pennock, Sepp Kipfstuhl, and Martyn R. Drury
Solid Earth, 8, 883–898, https://doi.org/10.5194/se-8-883-2017, https://doi.org/10.5194/se-8-883-2017, 2017
Short summary
Short summary
Understanding the flow of large ice masses on Earth is a major challenge in our changing climate. Deformation mechanisms are governed by the strong anisotropy of ice. As anisotropy is currently moving into the focus of ice sheet flow studies, we provide a detailed analysis of microstructure data from natural ice core samples which directly relate to anisotropic plasticity. Our findings reveal surprising dislocation activity which seems to contradict the concept of macroscopic ice anisotropy.
Damiano Della Lunga, Wolfgang Müller, Sune Olander Rasmussen, Anders Svensson, and Paul Vallelonga
The Cryosphere, 11, 1297–1309, https://doi.org/10.5194/tc-11-1297-2017, https://doi.org/10.5194/tc-11-1297-2017, 2017
Short summary
Short summary
In our study we combined the wealth of information provided by Greenland ice cores with an ultra-high-resolution technique well known in geoscience (laser ablation). Our set-up was developed and applied to investigate the variability in concentration of ions across a rapid climatic change from the oldest part of the last glaciation, showing that concentrations drop abruptly from cold to warm periods, representing a shift in atmospheric transport that happens even faster than previously thought.
Jan Eichler, Ina Kleitz, Maddalena Bayer-Giraldi, Daniela Jansen, Sepp Kipfstuhl, Wataru Shigeyama, Christian Weikusat, and Ilka Weikusat
The Cryosphere, 11, 1075–1090, https://doi.org/10.5194/tc-11-1075-2017, https://doi.org/10.5194/tc-11-1075-2017, 2017
Short summary
Short summary
This study contributes to investigations of the effect of impurities on ice microstructure and flow properties. For the first time we mapped over 5000 micro-inclusions in four samples from the EDML and NEEM polar ice cores. The particle distributions show no correlation with grain boundaries and thus we conclude that particle pinning plays only a secondary role for the microstructure evolution. Alternative mechanisms are discussed.
Grant M. Raisbeck, Alexandre Cauquoin, Jean Jouzel, Amaelle Landais, Jean-Robert Petit, Vladimir Y. Lipenkov, Juerg Beer, Hans-Arno Synal, Hans Oerter, Sigfus J. Johnsen, Jorgen P. Steffensen, Anders Svensson, and Françoise Yiou
Clim. Past, 13, 217–229, https://doi.org/10.5194/cp-13-217-2017, https://doi.org/10.5194/cp-13-217-2017, 2017
Short summary
Short summary
Using records of a long-lived radioactive nuclide (10Be) that is formed globally in the atmosphere and deposited within a few years to the earth’s surface, we have synchronized three Antarctic ice cores to one from Greenland. This permits the climate and other environmental parameters registered in these ice cores to be put on a common timescale with a precision of a few decades, thus allowing different models and mechanisms associated with these parameters to be tested with the same precision.
Florian Steinbach, Paul D. Bons, Albert Griera, Daniela Jansen, Maria-Gema Llorens, Jens Roessiger, and Ilka Weikusat
The Cryosphere, 10, 3071–3089, https://doi.org/10.5194/tc-10-3071-2016, https://doi.org/10.5194/tc-10-3071-2016, 2016
Short summary
Short summary
How glaciers or ice sheets flow is a result of microscopic processes controlled by the properties of individual ice crystals. We performed computer simulations on these processes and the effect of air bubbles between crystals. The simulations show that small-scale ice deformation is locally stronger than in other regions, which is enhanced by bubbles. This causes the ice crystals to recrystallise and change their properties in a way that potentially also affects the large-scale flow properties.
Agnès Maurel, Jean-François Mercier, and Maurine Montagnat
The Cryosphere, 10, 3063–3070, https://doi.org/10.5194/tc-10-3063-2016, https://doi.org/10.5194/tc-10-3063-2016, 2016
Short summary
Short summary
Crystallographic texture evolution with depth along ice cores can be evaluated using borehole sonic logging measurements. These measurements provide the velocities of elastic waves that depend on the ice polycrystal anisotropy and can further be related to the ice texture. To do so, elastic velocities need to be inverted from a modeling approach that relate elastic velocities to ice texture. The present paper presents a critical analysis of the different methods used for the inversion.
Amaelle Landais, Valérie Masson-Delmotte, Emilie Capron, Petra M. Langebroek, Pepijn Bakker, Emma J. Stone, Niklaus Merz, Christoph C. Raible, Hubertus Fischer, Anaïs Orsi, Frédéric Prié, Bo Vinther, and Dorthe Dahl-Jensen
Clim. Past, 12, 1933–1948, https://doi.org/10.5194/cp-12-1933-2016, https://doi.org/10.5194/cp-12-1933-2016, 2016
Short summary
Short summary
The last lnterglacial (LIG; 116 000 to 129 000 years before present) surface temperature at the upstream Greenland NEEM deposition site is estimated to be warmer by +7 to +11 °C compared to the preindustrial period. We show that under such warm temperatures, melting of snow probably led to a significant surface melting. There is a paradox between the extent of the Greenland ice sheet during the LIG and the strong warming during this period that models cannot solve.
Alexandra Touzeau, Amaëlle Landais, Barbara Stenni, Ryu Uemura, Kotaro Fukui, Shuji Fujita, Sarah Guilbaud, Alexey Ekaykin, Mathieu Casado, Eugeni Barkan, Boaz Luz, Olivier Magand, Grégory Teste, Emmanuel Le Meur, Mélanie Baroni, Joël Savarino, Ilann Bourgeois, and Camille Risi
The Cryosphere, 10, 837–852, https://doi.org/10.5194/tc-10-837-2016, https://doi.org/10.5194/tc-10-837-2016, 2016
Short summary
Short summary
The relationship between water isotope ratios and temperature is investigated in precipitation snow at Vostok and Dome C, as well as in surface snow along traverses. The temporal slope of the linear regression for the precipitation is smaller than the geographical slope. Thus, using the latter could lead to an underestimation of past temperature changes. The processes active at remote sites (best glacial analogs) are explored through a combination of water isotopes in short snow pits.
Thomas Goossens, Célia J. Sapart, Dorthe Dahl-Jensen, Trevor Popp, Saïda El Amri, and Jean-Louis Tison
The Cryosphere, 10, 553–567, https://doi.org/10.5194/tc-10-553-2016, https://doi.org/10.5194/tc-10-553-2016, 2016
Short summary
Short summary
This first multi-parametric analysis of the basal ice layer of the NEEM ice core reveals that its formation does not result from a mixing process between local relict ice and the deepest ice layers of the advancing ice sheet during its growth phase. Instead, it is shown that the basal sequence partly originates from melting and refreezing processes acting at the ice/bedrock interface under a well-developed ice sheet. These have partially destroyed the paleoclimatic records of the ice.
D. Jansen, M.-G. Llorens, J. Westhoff, F. Steinbach, S. Kipfstuhl, P. D. Bons, A. Griera, and I. Weikusat
The Cryosphere, 10, 359–370, https://doi.org/10.5194/tc-10-359-2016, https://doi.org/10.5194/tc-10-359-2016, 2016
Short summary
Short summary
In this study we present examples of typical small-scale folds observed in the NEEM ice core, North Greenland, and discuss their characteristics. Numerical modelling of viscoplastic deformation and dynamic recrystallisation was used to improve the understanding of the formation of the observed structures under simple shear boundary conditions. We conclude that the folds originate from bands of grains with a tilted lattice relative to the strong lattice preferred orientation below 1500 m depth.
S. Fujita, F. Parrenin, M. Severi, H. Motoyama, and E. W. Wolff
Clim. Past, 11, 1395–1416, https://doi.org/10.5194/cp-11-1395-2015, https://doi.org/10.5194/cp-11-1395-2015, 2015
A. Svensson, S. Fujita, M. Bigler, M. Braun, R. Dallmayr, V. Gkinis, K. Goto-Azuma, M. Hirabayashi, K. Kawamura, S. Kipfstuhl, H. A. Kjær, T. Popp, M. Simonsen, J. P. Steffensen, P. Vallelonga, and B. M. Vinther
Clim. Past, 11, 1127–1137, https://doi.org/10.5194/cp-11-1127-2015, https://doi.org/10.5194/cp-11-1127-2015, 2015
J.-L. Tison, M. de Angelis, G. Littot, E. Wolff, H. Fischer, M. Hansson, M. Bigler, R. Udisti, A. Wegner, J. Jouzel, B. Stenni, S. Johnsen, V. Masson-Delmotte, A. Landais, V. Lipenkov, L. Loulergue, J.-M. Barnola, J.-R. Petit, B. Delmonte, G. Dreyfus, D. Dahl-Jensen, G. Durand, B. Bereiter, A. Schilt, R. Spahni, K. Pol, R. Lorrain, R. Souchez, and D. Samyn
The Cryosphere, 9, 1633–1648, https://doi.org/10.5194/tc-9-1633-2015, https://doi.org/10.5194/tc-9-1633-2015, 2015
Short summary
Short summary
The oldest paleoclimatic information is buried within the lowermost layers of deep ice cores. It is therefore essential to judge how deep these records remain unaltered. We study the bottom 60 meters of the EPICA Dome C ice core from central Antarctica to show that the paleoclimatic signal is only affected at the small scale (decimeters) in terms of some of the global ice properties. However our data suggest that the time scale has been considerably distorted by mechanical stretching.
N. B. Karlsson and D. Dahl-Jensen
The Cryosphere, 9, 1465–1479, https://doi.org/10.5194/tc-9-1465-2015, https://doi.org/10.5194/tc-9-1465-2015, 2015
A. Diez, O. Eisen, C. Hofstede, A. Lambrecht, C. Mayer, H. Miller, D. Steinhage, T. Binder, and I. Weikusat
The Cryosphere, 9, 385–398, https://doi.org/10.5194/tc-9-385-2015, https://doi.org/10.5194/tc-9-385-2015, 2015
F. Parrenin, S. Fujita, A. Abe-Ouchi, K. Kawamura, V. Masson-Delmotte, H. Motoyama, F. Saito, M. Severi, B. Stenni, R. Uemura, and E. Wolff
Clim. Past Discuss., https://doi.org/10.5194/cpd-11-377-2015, https://doi.org/10.5194/cpd-11-377-2015, 2015
Revised manuscript has not been submitted
K. Hara, F. Nakazawa, S. Fujita, K. Fukui, H. Enomoto, and S. Sugiyama
Atmos. Chem. Phys., 14, 10211–10230, https://doi.org/10.5194/acp-14-10211-2014, https://doi.org/10.5194/acp-14-10211-2014, 2014
P. Vallelonga, K. Christianson, R. B. Alley, S. Anandakrishnan, J. E. M. Christian, D. Dahl-Jensen, V. Gkinis, C. Holme, R. W. Jacobel, N. B. Karlsson, B. A. Keisling, S. Kipfstuhl, H. A. Kjær, M. E. L. Kristensen, A. Muto, L. E. Peters, T. Popp, K. L. Riverman, A. M. Svensson, C. Tibuleac, B. M. Vinther, Y. Weng, and M. Winstrup
The Cryosphere, 8, 1275–1287, https://doi.org/10.5194/tc-8-1275-2014, https://doi.org/10.5194/tc-8-1275-2014, 2014
H. C. Steen-Larsen, V. Masson-Delmotte, M. Hirabayashi, R. Winkler, K. Satow, F. Prié, N. Bayou, E. Brun, K. M. Cuffey, D. Dahl-Jensen, M. Dumont, M. Guillevic, S. Kipfstuhl, A. Landais, T. Popp, C. Risi, K. Steffen, B. Stenni, and A. E. Sveinbjörnsdottír
Clim. Past, 10, 377–392, https://doi.org/10.5194/cp-10-377-2014, https://doi.org/10.5194/cp-10-377-2014, 2014
S. O. Rasmussen, P. M. Abbott, T. Blunier, A. J. Bourne, E. Brook, S. L. Buchardt, C. Buizert, J. Chappellaz, H. B. Clausen, E. Cook, D. Dahl-Jensen, S. M. Davies, M. Guillevic, S. Kipfstuhl, T. Laepple, I. K. Seierstad, J. P. Severinghaus, J. P. Steffensen, C. Stowasser, A. Svensson, P. Vallelonga, B. M. Vinther, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 2713–2730, https://doi.org/10.5194/cp-9-2713-2013, https://doi.org/10.5194/cp-9-2713-2013, 2013
H. Fischer, J. Severinghaus, E. Brook, E. Wolff, M. Albert, O. Alemany, R. Arthern, C. Bentley, D. Blankenship, J. Chappellaz, T. Creyts, D. Dahl-Jensen, M. Dinn, M. Frezzotti, S. Fujita, H. Gallee, R. Hindmarsh, D. Hudspeth, G. Jugie, K. Kawamura, V. Lipenkov, H. Miller, R. Mulvaney, F. Parrenin, F. Pattyn, C. Ritz, J. Schwander, D. Steinhage, T. van Ommen, and F. Wilhelms
Clim. Past, 9, 2489–2505, https://doi.org/10.5194/cp-9-2489-2013, https://doi.org/10.5194/cp-9-2489-2013, 2013
J.-F. Lamarque, F. Dentener, J. McConnell, C.-U. Ro, M. Shaw, R. Vet, D. Bergmann, P. Cameron-Smith, S. Dalsoren, R. Doherty, G. Faluvegi, S. J. Ghan, B. Josse, Y. H. Lee, I. A. MacKenzie, D. Plummer, D. T. Shindell, R. B. Skeie, D. S. Stevenson, S. Strode, G. Zeng, M. Curran, D. Dahl-Jensen, S. Das, D. Fritzsche, and M. Nolan
Atmos. Chem. Phys., 13, 7997–8018, https://doi.org/10.5194/acp-13-7997-2013, https://doi.org/10.5194/acp-13-7997-2013, 2013
L. Bazin, A. Landais, B. Lemieux-Dudon, H. Toyé Mahamadou Kele, D. Veres, F. Parrenin, P. Martinerie, C. Ritz, E. Capron, V. Lipenkov, M.-F. Loutre, D. Raynaud, B. Vinther, A. Svensson, S. O. Rasmussen, M. Severi, T. Blunier, M. Leuenberger, H. Fischer, V. Masson-Delmotte, J. Chappellaz, and E. Wolff
Clim. Past, 9, 1715–1731, https://doi.org/10.5194/cp-9-1715-2013, https://doi.org/10.5194/cp-9-1715-2013, 2013
D. Veres, L. Bazin, A. Landais, H. Toyé Mahamadou Kele, B. Lemieux-Dudon, F. Parrenin, P. Martinerie, E. Blayo, T. Blunier, E. Capron, J. Chappellaz, S. O. Rasmussen, M. Severi, A. Svensson, B. Vinther, and E. W. Wolff
Clim. Past, 9, 1733–1748, https://doi.org/10.5194/cp-9-1733-2013, https://doi.org/10.5194/cp-9-1733-2013, 2013
H. C. Steen-Larsen, S. J. Johnsen, V. Masson-Delmotte, B. Stenni, C. Risi, H. Sodemann, D. Balslev-Clausen, T. Blunier, D. Dahl-Jensen, M. D. Ellehøj, S. Falourd, A. Grindsted, V. Gkinis, J. Jouzel, T. Popp, S. Sheldon, S. B. Simonsen, J. Sjolte, J. P. Steffensen, P. Sperlich, A. E. Sveinbjörnsdóttir, B. M. Vinther, and J. W. C. White
Atmos. Chem. Phys., 13, 4815–4828, https://doi.org/10.5194/acp-13-4815-2013, https://doi.org/10.5194/acp-13-4815-2013, 2013
A. Svensson, M. Bigler, T. Blunier, H. B. Clausen, D. Dahl-Jensen, H. Fischer, S. Fujita, K. Goto-Azuma, S. J. Johnsen, K. Kawamura, S. Kipfstuhl, M. Kohno, F. Parrenin, T. Popp, S. O. Rasmussen, J. Schwander, I. Seierstad, M. Severi, J. P. Steffensen, R. Udisti, R. Uemura, P. Vallelonga, B. M. Vinther, A. Wegner, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 749–766, https://doi.org/10.5194/cp-9-749-2013, https://doi.org/10.5194/cp-9-749-2013, 2013
P. Fretwell, H. D. Pritchard, D. G. Vaughan, J. L. Bamber, N. E. Barrand, R. Bell, C. Bianchi, R. G. Bingham, D. D. Blankenship, G. Casassa, G. Catania, D. Callens, H. Conway, A. J. Cook, H. F. J. Corr, D. Damaske, V. Damm, F. Ferraccioli, R. Forsberg, S. Fujita, Y. Gim, P. Gogineni, J. A. Griggs, R. C. A. Hindmarsh, P. Holmlund, J. W. Holt, R. W. Jacobel, A. Jenkins, W. Jokat, T. Jordan, E. C. King, J. Kohler, W. Krabill, M. Riger-Kusk, K. A. Langley, G. Leitchenkov, C. Leuschen, B. P. Luyendyk, K. Matsuoka, J. Mouginot, F. O. Nitsche, Y. Nogi, O. A. Nost, S. V. Popov, E. Rignot, D. M. Rippin, A. Rivera, J. Roberts, N. Ross, M. J. Siegert, A. M. Smith, D. Steinhage, M. Studinger, B. Sun, B. K. Tinto, B. C. Welch, D. Wilson, D. A. Young, C. Xiangbin, and A. Zirizzotti
The Cryosphere, 7, 375–393, https://doi.org/10.5194/tc-7-375-2013, https://doi.org/10.5194/tc-7-375-2013, 2013
S. L. Buchardt, H. B. Clausen, B. M. Vinther, and D. Dahl-Jensen
Clim. Past, 8, 2053–2059, https://doi.org/10.5194/cp-8-2053-2012, https://doi.org/10.5194/cp-8-2053-2012, 2012
Related subject area
Ice Cores
Development and fluctuation of crystal orientation fabric in the deep sections of the Dome Fuji ice core, Antarctica: impacts of dust particles and migration recrystallization
A 350,000-year-old blue ice identified at the surface of the Elephant Moraine region, East Antarctica
What does the impurity variability at the microscale represent in ice cores? Insights from a conceptual approach
Reconstruction of mass balance and firn stratigraphy during the 1996–2011 warm period at high-altitude on Mt. Ortles, Eastern Alps: a comparison of modelled and ice core results
Brief Communication: The Danish Replicate Drilling System – Results from the First Field Test
Laser ablation inductively coupled plasma mass spectrometry measurements for high-resolution chemical ice core analyses with a first application to an ice core from Skytrain Ice Rise (Antarctica)
The grain-scale signature of isotopic diffusion in ice
Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores – results from the EastGRIP region
Scientific history, sampling approach, and physical characterization of the Camp Century subglacial material, a rare archive from beneath the Greenland Ice Sheet
Novel approach to estimate the water isotope diffusion length in deep ice cores with an application to Marine Isotope Stage 19 in the Dome C ice core
The potential of in situ cosmogenic 14CO in ice cores as a proxy for galactic cosmic ray flux variations
Characterization of in situ cosmogenic 14CO production, retention and loss in firn and shallow ice at Summit, Greenland
Research into mechanical modeling based on characteristics of the fracture mechanics of ice cutting for scientific drilling in polar regions
Temporal markers in a temperate ice core: insights from 3H and 137Cs profiles from the Adamello Glacier
Review article: Melt-affected ice cores for polar research in a warming world
Impact of subsurface crevassing on the depth–age relationship of high-Alpine ice cores extracted at Col du Dôme between 1994 and 2012
Fifty years of firn evolution on Grigoriev ice cap, Tien Shan, Kyrgyzstan
Climate change is rapidly deteriorating the climatic signal in Svalbard glaciers
Identifying atmospheric processes favouring the formation of bubble-free layers in the Law Dome ice core, East Antarctica
Millennial and orbital-scale variability in a 54 000-year record of total air content from the South Pole ice core
Investigating the spatial representativeness of East Antarctic ice cores: a comparison of ice core and radar-derived surface mass balance over coastal ice rises and Dome Fuji
Early Holocene ice on the Begguya plateau (Mt. Hunter, Alaska) revealed by ice core 14C age constraints
Greenland and Canadian Arctic ice temperature profiles database
Isotopic diffusion in ice enhanced by vein-water flow
A one-dimensional temperature and age modeling study for selecting the drill site of the oldest ice core near Dome Fuji, Antarctica
Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within
Using ice core measurements from Taylor Glacier, Antarctica, to calibrate in situ cosmogenic 14C production rates by muons
Detection of ice core particles via deep neural networks
Development of crystal orientation fabric in the Dome Fuji ice core in East Antarctica: implications for the deformation regime in ice sheets
Gas isotope thermometry in the South Pole and Dome Fuji ice cores provides evidence for seasonal rectification of ice core gas records
Chronostratigraphy of the Larsen blue-ice area in northern Victoria Land, East Antarctica, and its implications for paleoclimate
A quantitative method of resolving annual precipitation for the past millennia from Tibetan ice cores
Regional variability of diatoms in ice cores from the Antarctic Peninsula and Ellsworth Land, Antarctica
Microstructure, micro-inclusions, and mineralogy along the EGRIP (East Greenland Ice Core Project) ice core – Part 2: Implications for palaeo-mineralogy
Microstructure, micro-inclusions, and mineralogy along the EGRIP ice core – Part 1: Localisation of inclusions and deformation patterns
Fractionation of O2∕N2 and Ar∕N2 in the Antarctic ice sheet during bubble formation and bubble–clathrate hydrate transition from precise gas measurements of the Dome Fuji ice core
Deep ice as a geochemical reactor: insights from iron speciation and mineralogy of dust in the Talos Dome ice core (East Antarctica)
Two-dimensional impurity imaging in deep Antarctic ice cores: snapshots of three climatic periods and implications for high-resolution signal interpretation
Acoustic velocity measurements for detecting the crystal orientation fabrics of a temperate ice core
Brief communication: New evidence further constraining Tibetan ice core chronologies to the Holocene
Brief communication: New radar constraints support presence of ice older than 1.5 Myr at Little Dome C
Pervasive diffusion of climate signals recorded in ice-vein ionic impurities
Radiocarbon dating of alpine ice cores with the dissolved organic carbon (DOC) fraction
Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano
Physical properties of shallow ice cores from Antarctic and sub-Antarctic islands
Stable water isotopes and accumulation rates in the Union Glacier region, Ellsworth Mountains, West Antarctica, over the last 35 years
Multi-tracer study of gas trapping in an East Antarctic ice core
Very old firn air linked to strong density layering at Styx Glacier, coastal Victoria Land, East Antarctica
Apparent discrepancy of Tibetan ice core δ18O records may be attributed to misinterpretation of chronology
Challenges associated with the climatic interpretation of water stable isotope records from a highly resolved firn core from Adélie Land, coastal Antarctica
Tomotaka Saruya, Atsushi Miyamoto, Shuji Fujita, Kumiko Goto-Azuma, Motohiro Hirabayashi, Akira Hori, Makoto Igarashi, Yoshinori Iizuka, Takao Kameda, Hiroshi Ohno, Wataru Shigeyama, and Shun Tsutaki
The Cryosphere, 19, 2365–2385, https://doi.org/10.5194/tc-19-2365-2025, https://doi.org/10.5194/tc-19-2365-2025, 2025
Short summary
Short summary
Crystal orientation fabrics and microstructures in the deep sections of the Dome Fuji (DF) ice core were investigated using innovative methods with dense depth coverage. Together with our previous studies, we have obtained whole layer profiles of the crystal orientation fabric and physical properties of the DF ice core. Development and fluctuation of the crystal orientation fabric were found to be highly dependent on impurity concentrations and recrystallization processes.
Giyoon Lee, Jinho Ahn, Hyeontae Ju, Ikumi Oyabu, Florian Ritterbusch, Songyi Kim, Jangil Moon, Joohan Lee, Yeongcheol Han, Soon Do Hur, Kenji Kawamura, Zheng-Tian Lu, Wei Jiang, and Guo-Min Yang
EGUsphere, https://doi.org/10.5194/egusphere-2025-1436, https://doi.org/10.5194/egusphere-2025-1436, 2025
Short summary
Short summary
This study investigated ancient ice in the Elephant Moraine, East Antarctica. Using geophysical surveys and chemical analyses, we found surface ice around 350,000 years old and ice thickness ranging from 200 to 800 meters. These findings suggest the Elephant Moraine region may preserve ice over one million years old at depths of several hundred meters. Recovering such ice is a key goal in paleoclimate research to better understand the climate history of Earth.
Piers Larkman, Rachael H. Rhodes, Nicolas Stoll, Carlo Barbante, and Pascal Bohleber
The Cryosphere, 19, 1373–1390, https://doi.org/10.5194/tc-19-1373-2025, https://doi.org/10.5194/tc-19-1373-2025, 2025
Short summary
Short summary
Impurities in ice cores can be preferentially located at the boundaries between crystals of ice, impacting the interpretation of high-resolution data collected from ice core samples. Through use of a modelling framework, we demonstrate that one-dimensional signals can be significantly affected by this association, meaning high-resolution measurements must be carefully designed. Accounting for this effect is important for interpreting ice core data, especially for deep ice samples.
Luca Carturan, Alexander C. Ihle, Federico Cazorzi, Tiziana Lazzarina Zendrini, Fabrizio De Blasi, Giancarlo Dalla Fontana, Giuliano Dreossi, Daniela Festi, Bryan Mark, Klaus Dieter Oeggl, Roberto Seppi, Barbara Stenni, and Paolo Gabrielli
EGUsphere, https://doi.org/10.5194/egusphere-2025-729, https://doi.org/10.5194/egusphere-2025-729, 2025
Short summary
Short summary
Paleoclimatic glacial archives in low-latitude mountains are increasingly affected by melt, causing heavy percolation and removing snow and firn accumulated across months, seasons or even years. Here we present a proxy system model that explicitly accounts for melt in ice and firn cores. Compared to traditional annual layer counting, the model significantly improved the interpretation and annual dating of the Mt. Ortles firn core, in the Italian Alps, that includes the very warm summer 2003.
Julien Westhoff, Grant Vernon Boeckmann, Nicholas Mossor Rathmann, and Steffen Bo Hansen
EGUsphere, https://doi.org/10.5194/egusphere-2024-3081, https://doi.org/10.5194/egusphere-2024-3081, 2024
Short summary
Short summary
We report on the successful test of a new replicate drilling system for ice cores. This system allows us to deviate the ice core drill from the parent, the original, borehole, and drill into the side of the wall. Thus, we can produce a second ice core from any desired depth, increasing the amount of sample available for scientific purposes. In the manuscript, we present the results from the first field tests and the challenges we encountered.
Helene Hoffmann, Jason Day, Rachael H. Rhodes, Mackenzie Grieman, Jack Humby, Isobel Rowell, Christoph Nehrbass-Ahles, Robert Mulvaney, Sally Gibson, and Eric Wolff
The Cryosphere, 18, 4993–5013, https://doi.org/10.5194/tc-18-4993-2024, https://doi.org/10.5194/tc-18-4993-2024, 2024
Short summary
Short summary
Ice cores are archives of past atmospheric conditions. In deep and old ice, the layers containing this information get thinned to the millimetre scale or below. We installed a setup for high-resolution (182 μm) chemical impurity measurements in ice cores using the laser ablation technique at the University of Cambridge. In a first application to the Skytrain ice core from Antarctica, we discuss the potential to detect fine-layered structures in ice up to an age of 26 000 years.
Felix S. L. Ng
The Cryosphere, 18, 4645–4669, https://doi.org/10.5194/tc-18-4645-2024, https://doi.org/10.5194/tc-18-4645-2024, 2024
Short summary
Short summary
Liquid veins and grain boundaries in ice can accelerate the decay of climate signals in δ18O and δD by short-circuiting the slow isotopic diffusion in crystal grains. This theory for "excess diffusion" has not been confirmed experimentally. We show that, if the mechanism occurs, then distinct isotopic patterns must form near grain junctions, offering a testable prediction of the theory. We calculate the patterns and describe an experimental scheme for testing ice-core samples for the mechanism.
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.
Paul R. Bierman, Andrew J. Christ, Catherine M. Collins, Halley M. Mastro, Juliana Souza, Pierre-Henri Blard, Stefanie Brachfeld, Zoe R. Courville, Tammy M. Rittenour, Elizabeth K. Thomas, Jean-Louis Tison, and François Fripiat
The Cryosphere, 18, 4029–4052, https://doi.org/10.5194/tc-18-4029-2024, https://doi.org/10.5194/tc-18-4029-2024, 2024
Short summary
Short summary
In 1966, the U.S. Army drilled through the Greenland Ice Sheet at Camp Century, Greenland; they recovered 3.44 m of frozen material. Here, we decipher the material’s history. Water, flowing during a warm interglacial when the ice sheet melted from northwest Greenland, deposited the upper material which contains fossil plant and insect parts. The lower material, separated by more than a meter of ice with some sediment, is till, deposited by the ice sheet during a prior cold period.
Fyntan Shaw, Andrew M. Dolman, Torben Kunz, Vasileios Gkinis, and Thomas Laepple
The Cryosphere, 18, 3685–3698, https://doi.org/10.5194/tc-18-3685-2024, https://doi.org/10.5194/tc-18-3685-2024, 2024
Short summary
Short summary
Fast variability of water isotopes in ice cores is attenuated by diffusion but can be restored if the diffusion length is accurately estimated. Current estimation methods are inadequate for deep ice, mischaracterising millennial-scale climate variability. We address this using variability estimates from shallower ice. The estimated diffusion length of 31 cm for the bottom of the Dome C ice core is 20 cm less than the old method, enabling signal recovery on timescales previously considered lost.
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
Short summary
Short summary
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
Short summary
Short summary
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.
Xinyu Lv, Zhihao Cui, Ting Wang, Yumin Wen, An Liu, and Rusheng Wang
The Cryosphere, 18, 3351–3362, https://doi.org/10.5194/tc-18-3351-2024, https://doi.org/10.5194/tc-18-3351-2024, 2024
Short summary
Short summary
In this study, the formation process of ice chips was observed and the fracture mechanics characteristics of the ice during the cutting process were analyzed. Additionally, a mechanical model for the cutting force was established based on the observation and analysis results. Finally, influencing factors and laws of the cutting force were verified by cutting force test results generated under various experimental conditions.
Elena Di Stefano, Giovanni Baccolo, Massimiliano Clemenza, Barbara Delmonte, Deborah Fiorini, Roberto Garzonio, Margit Schwikowski, and Valter Maggi
The Cryosphere, 18, 2865–2874, https://doi.org/10.5194/tc-18-2865-2024, https://doi.org/10.5194/tc-18-2865-2024, 2024
Short summary
Short summary
Rising temperatures are impacting the reliability of glaciers as environmental archives. This study reports how meltwater percolation affects the distribution of tritium and cesium, which are commonly used as temporal markers in dating ice cores, in a temperate glacier. Our findings challenge the established application of radionuclides for dating mountain ice cores and indicate tritium as the best choice.
Dorothea Elisabeth Moser, Elizabeth R. Thomas, Christoph Nehrbass-Ahles, Anja Eichler, and Eric Wolff
The Cryosphere, 18, 2691–2718, https://doi.org/10.5194/tc-18-2691-2024, https://doi.org/10.5194/tc-18-2691-2024, 2024
Short summary
Short summary
Increasing temperatures worldwide lead to more melting of glaciers and ice caps, even in the polar regions. This is why ice-core scientists need to prepare to analyse records affected by melting and refreezing. In this paper, we present a summary of how near-surface melt forms, what structural imprints it leaves in snow, how various signatures used for ice-core climate reconstruction are altered, and how we can still extract valuable insights from melt-affected ice cores.
Susanne Preunkert, Pascal Bohleber, Michel Legrand, Adrien Gilbert, Tobias Erhardt, Roland Purtschert, Lars Zipf, Astrid Waldner, Joseph R. McConnell, and Hubertus Fischer
The Cryosphere, 18, 2177–2194, https://doi.org/10.5194/tc-18-2177-2024, https://doi.org/10.5194/tc-18-2177-2024, 2024
Short summary
Short summary
Ice cores from high-elevation Alpine glaciers are an important tool to reconstruct the past atmosphere. However, since crevasses are common at these glacier sites, rigorous investigations of glaciological conditions upstream of drill sites are needed before interpreting such ice cores. On the basis of three ice cores extracted at Col du Dôme (4250 m a.s.l; French Alps), an overall picture of a dynamic crevasse formation is drawn, which disturbs the depth–age relation of two of the three cores.
Horst Machguth, Anja Eichler, Margit Schwikowski, Sabina Brütsch, Enrico Mattea, Stanislav Kutuzov, Martin Heule, Ryskul Usubaliev, Sultan Belekov, Vladimir N. Mikhalenko, Martin Hoelzle, and Marlene Kronenberg
The Cryosphere, 18, 1633–1646, https://doi.org/10.5194/tc-18-1633-2024, https://doi.org/10.5194/tc-18-1633-2024, 2024
Short summary
Short summary
In 2018 we drilled an 18 m ice core on the summit of Grigoriev ice cap, located in the Tien Shan mountains of Kyrgyzstan. The core analysis reveals strong melting since the early 2000s. Regardless of this, we find that the structure and temperature of the ice have changed little since the 1980s. The probable cause of this apparent stability is (i) an increase in snowfall and (ii) the fact that meltwater nowadays leaves the glacier and thereby removes so-called latent heat.
Andrea Spolaor, Federico Scoto, Catherine Larose, Elena Barbaro, Francois Burgay, Mats P. Bjorkman, David Cappelletti, Federico Dallo, Fabrizio de Blasi, Dmitry Divine, Giuliano Dreossi, Jacopo Gabrieli, Elisabeth Isaksson, Jack Kohler, Tonu Martma, Louise S. Schmidt, Thomas V. Schuler, Barbara Stenni, Clara Turetta, Bartłomiej Luks, Mathieu Casado, and Jean-Charles Gallet
The Cryosphere, 18, 307–320, https://doi.org/10.5194/tc-18-307-2024, https://doi.org/10.5194/tc-18-307-2024, 2024
Short summary
Short summary
We evaluate the impact of the increased snowmelt on the preservation of the oxygen isotope (δ18O) signal in firn records recovered from the top of the Holtedahlfonna ice field located in the Svalbard archipelago. Thanks to a multidisciplinary approach we demonstrate a progressive deterioration of the isotope signal in the firn core. We link the degradation of the δ18O signal to the increased occurrence and intensity of melt events associated with the rapid warming occurring in the archipelago.
Lingwei Zhang, Tessa R. Vance, Alexander D. Fraser, Lenneke M. Jong, Sarah S. Thompson, Alison S. Criscitiello, and Nerilie J. Abram
The Cryosphere, 17, 5155–5173, https://doi.org/10.5194/tc-17-5155-2023, https://doi.org/10.5194/tc-17-5155-2023, 2023
Short summary
Short summary
Physical features in ice cores provide unique records of past variability. We identified 1–2 mm ice layers without bubbles in surface ice cores from Law Dome, East Antarctica, occurring on average five times per year. The origin of these bubble-free layers is unknown. In this study, we investigate whether they have the potential to record past atmospheric processes and circulation. We find that the bubble-free layers are linked to accumulation hiatus events and meridional moisture transport.
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
Short summary
Short summary
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.
Marie G. P. Cavitte, Hugues Goosse, Kenichi Matsuoka, Sarah Wauthy, Vikram Goel, Rahul Dey, Bhanu Pratap, Brice Van Liefferinge, Thamban Meloth, and Jean-Louis Tison
The Cryosphere, 17, 4779–4795, https://doi.org/10.5194/tc-17-4779-2023, https://doi.org/10.5194/tc-17-4779-2023, 2023
Short summary
Short summary
The net accumulation of snow over Antarctica is key for assessing current and future sea-level rise. Ice cores record a noisy snowfall signal to verify model simulations. We find that ice core net snowfall is biased to lower values for ice rises and the Dome Fuji site (Antarctica), while the relative uncertainty in measuring snowfall increases rapidly with distance away from the ice core sites at the ice rises but not at Dome Fuji. Spatial variation in snowfall must therefore be considered.
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
Short summary
Short summary
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.
Anja Løkkegaard, Kenneth D. Mankoff, Christian Zdanowicz, Gary D. Clow, Martin P. Lüthi, Samuel H. Doyle, Henrik H. Thomsen, David Fisher, Joel Harper, Andy Aschwanden, Bo M. Vinther, Dorthe Dahl-Jensen, Harry Zekollari, Toby Meierbachtol, Ian McDowell, Neil Humphrey, Anne Solgaard, Nanna B. Karlsson, Shfaqat A. Khan, Benjamin Hills, Robert Law, Bryn Hubbard, Poul Christoffersen, Mylène Jacquemart, Julien Seguinot, Robert S. Fausto, and William T. Colgan
The Cryosphere, 17, 3829–3845, https://doi.org/10.5194/tc-17-3829-2023, https://doi.org/10.5194/tc-17-3829-2023, 2023
Short summary
Short summary
This study presents a database compiling 95 ice temperature profiles from the Greenland ice sheet and peripheral ice caps. Ice viscosity and hence ice flow are highly sensitive to ice temperature. To highlight the value of the database in evaluating ice flow simulations, profiles from the Greenland ice sheet are compared to a modeled temperature field. Reoccurring discrepancies between modeled and observed temperatures provide insight on the difficulties faced when simulating ice temperatures.
Felix S. L. Ng
The Cryosphere, 17, 3063–3082, https://doi.org/10.5194/tc-17-3063-2023, https://doi.org/10.5194/tc-17-3063-2023, 2023
Short summary
Short summary
The stable isotopes of oxygen and hydrogen in ice cores are routinely analysed for the climate signals which they carry. It has long been known that the system of water veins in ice facilitates isotopic diffusion. Here, mathematical modelling shows that water flow in the veins strongly accelerates the diffusion and the decay of climate signals. The process hampers methods using the variations in signal decay with depth to reconstruct past climatic temperature.
Takashi Obase, Ayako Abe-Ouchi, Fuyuki Saito, Shun Tsutaki, Shuji Fujita, Kenji Kawamura, and Hideaki Motoyama
The Cryosphere, 17, 2543–2562, https://doi.org/10.5194/tc-17-2543-2023, https://doi.org/10.5194/tc-17-2543-2023, 2023
Short summary
Short summary
We use a one-dimensional ice-flow model to examine the most suitable core location near Dome Fuji (DF), Antarctica. This model computes the temporal evolution of age and temperature from past to present. We investigate the influence of different parameters of climate and ice sheet on the ice's basal age and compare the results with ground radar surveys. We find that the local ice thickness primarily controls the age because it is critical to the basal melting, which can eliminate the old ice.
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.
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
Short summary
Short summary
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.
Niccolò Maffezzoli, Eliza Cook, Willem G. M. van der Bilt, Eivind N. Støren, Daniela Festi, Florian Muthreich, Alistair W. R. Seddon, François Burgay, Giovanni Baccolo, Amalie R. F. Mygind, Troels Petersen, Andrea Spolaor, Sebastiano Vascon, Marcello Pelillo, Patrizia Ferretti, Rafael S. dos Reis, Jefferson C. Simões, Yuval Ronen, Barbara Delmonte, Marco Viccaro, Jørgen Peder Steffensen, Dorthe Dahl-Jensen, Kerim H. Nisancioglu, and Carlo Barbante
The Cryosphere, 17, 539–565, https://doi.org/10.5194/tc-17-539-2023, https://doi.org/10.5194/tc-17-539-2023, 2023
Short summary
Short summary
Multiple lines of research in ice core science are limited by manually intensive and time-consuming optical microscopy investigations for the detection of insoluble particles, from pollen grains to volcanic shards. To help overcome these limitations and support researchers, we present a novel methodology for the identification and autonomous classification of ice core insoluble particles based on flow image microscopy and neural networks.
Tomotaka Saruya, Shuji Fujita, Yoshinori Iizuka, Atsushi Miyamoto, Hiroshi Ohno, Akira Hori, Wataru Shigeyama, Motohiro Hirabayashi, and Kumiko Goto-Azuma
The Cryosphere, 16, 2985–3003, https://doi.org/10.5194/tc-16-2985-2022, https://doi.org/10.5194/tc-16-2985-2022, 2022
Short summary
Short summary
Crystal orientation fabrics (COF) of the Dome Fuji ice core were investigated with an innovative method with unprecedentedly high statistical significance and dense depth coverage. The COF profile and its fluctuation were found to be highly dependent on concentrations of chloride ion and dust. The data suggest deformation of ice at the deepest zone is highly influenced by COF fluctuations that progressively develop from the near-surface firn toward the deepest zone within ice sheets.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Wangbin Zhang, Shugui Hou, Shuang-Ye Wu, Hongxi Pang, Sharon B. Sneed, Elena V. Korotkikh, Paul A. Mayewski, Theo M. Jenk, and Margit Schwikowski
The Cryosphere, 16, 1997–2008, https://doi.org/10.5194/tc-16-1997-2022, https://doi.org/10.5194/tc-16-1997-2022, 2022
Short summary
Short summary
This study proposes a quantitative method to reconstruct annual precipitation records at the millennial timescale from the Tibetan ice cores through combining annual layer identification based on LA-ICP-MS measurement with an ice flow model. The reliability of this method is assessed by comparing our results with other reconstructed and modeled precipitation series for the Tibetan Plateau. The assessment shows that the method has a promising performance.
Dieter R. Tetzner, Claire S. Allen, and Elizabeth R. Thomas
The Cryosphere, 16, 779–798, https://doi.org/10.5194/tc-16-779-2022, https://doi.org/10.5194/tc-16-779-2022, 2022
Short summary
Short summary
The presence of diatoms in Antarctic ice cores has been scarcely documented and poorly understood. Here we present a detailed analysis of the spatial and temporal distribution of the diatom record preserved in a set of Antarctic ice cores. Our results reveal that the timing and amount of diatoms deposited present a strong geographical division. This study highlights the potential of the diatom record preserved in Antarctic ice cores to provide useful information about past environmental changes.
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.
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.
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
Short summary
Short summary
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.
Giovanni Baccolo, Barbara Delmonte, Elena Di Stefano, Giannantonio Cibin, Ilaria Crotti, Massimo Frezzotti, Dariush Hampai, Yoshinori Iizuka, Augusto Marcelli, and Valter Maggi
The Cryosphere, 15, 4807–4822, https://doi.org/10.5194/tc-15-4807-2021, https://doi.org/10.5194/tc-15-4807-2021, 2021
Short summary
Short summary
As scientists are pushing efforts to recover deep ice cores to extend paleoclimatic reconstructions, it is now essential to explore deep ice. The latter was considered a relatively stable environment, but this view is changing. This study shows that the conditions of deep ice promote the interaction between soluble and insoluble impurities, favoring complex geochemical reactions that lead to the englacial dissolution and precipitation of specific minerals present in atmospheric mineral dust.
Pascal Bohleber, Marco Roman, Martin Šala, Barbara Delmonte, Barbara Stenni, and Carlo Barbante
The Cryosphere, 15, 3523–3538, https://doi.org/10.5194/tc-15-3523-2021, https://doi.org/10.5194/tc-15-3523-2021, 2021
Short summary
Short summary
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers micro-destructive, micrometer-scale impurity analysis of ice cores. For improved understanding of the LA-ICP-MS signals, novel 2D impurity imaging is applied to selected glacial and interglacial samples of Antarctic deep ice cores. This allows evaluating the 2D impurity distribution in relation to ice crystal features and assessing implications for investigating highly thinned climate proxy signals in deep polar ice.
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.
Shugui Hou, Wangbin Zhang, Ling Fang, Theo M. Jenk, Shuangye Wu, Hongxi Pang, and Margit Schwikowski
The Cryosphere, 15, 2109–2114, https://doi.org/10.5194/tc-15-2109-2021, https://doi.org/10.5194/tc-15-2109-2021, 2021
Short summary
Short summary
We present ages for two new ice cores reaching bedrock, from the Zangser Kangri (ZK) glacier in the northwestern Tibetan Plateau and the Shulenanshan (SLNS) glacier in the western Qilian Mountains. We estimated bottom ages of 8.90±0.57/0.56 ka and 7.46±1.46/1.79 ka for the ZK and SLNS ice core respectively, constraining the time range accessible by Tibetan ice cores to the Holocene.
David A. Lilien, Daniel Steinhage, Drew Taylor, Frédéric Parrenin, Catherine Ritz, Robert Mulvaney, Carlos Martín, Jie-Bang Yan, Charles O'Neill, Massimo Frezzotti, Heinrich Miller, Prasad Gogineni, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, https://doi.org/10.5194/tc-15-1881-2021, 2021
Short summary
Short summary
We collected radar data between EDC, an ice core spanning ~800 000 years, and BELDC, the site chosen for a new
oldest icecore at nearby Little Dome C. These data allow us to identify 50 % older internal horizons than previously traced in the area. We fit a model to the ages of those horizons at BELDC to determine the age of deep ice there. We find that there is likely to be 1.5 Myr old ice ~265 m above the bed, with sufficient resolution to preserve desired climatic information.
Felix S. L. Ng
The Cryosphere, 15, 1787–1810, https://doi.org/10.5194/tc-15-1787-2021, https://doi.org/10.5194/tc-15-1787-2021, 2021
Short summary
Short summary
Current theory predicts climate signals in the vein chemistry of ice cores to migrate, hampering their dating. I show that the Gibbs–Thomson effect, which has been overlooked, causes fast diffusion that prevents signals from surviving into deep ice. Hence the deep climatic peaks in Antarctic and Greenlandic ice must be due to impurities in the ice matrix (outside veins) and safe from migration. These findings reset our understanding of postdepositional changes of ice-core climate signals.
Ling Fang, Theo M. Jenk, Thomas Singer, Shugui Hou, and Margit Schwikowski
The Cryosphere, 15, 1537–1550, https://doi.org/10.5194/tc-15-1537-2021, https://doi.org/10.5194/tc-15-1537-2021, 2021
Short summary
Short summary
The interpretation of the ice-core-preserved signal requires a precise chronology. Radiocarbon (14C) dating of the water-insoluble organic carbon (WIOC) fraction has become an important dating tool. However, this method is restricted by the low concentration in the ice. In this work, we report first 14C dating results using the dissolved organic carbon (DOC) fraction. The resulting ages are comparable in both fractions, but by using the DOC fraction the required ice mass can be reduced.
Filipe G. L. Lindau, Jefferson C. Simões, Barbara Delmonte, Patrick Ginot, Giovanni Baccolo, Chiara I. Paleari, Elena Di Stefano, Elena Korotkikh, Douglas S. Introne, Valter Maggi, Eduardo Garzanti, and Sergio Andò
The Cryosphere, 15, 1383–1397, https://doi.org/10.5194/tc-15-1383-2021, https://doi.org/10.5194/tc-15-1383-2021, 2021
Short summary
Short summary
Information about the past climate variability in tropical South America is stored in the snow layers of the tropical Andean glaciers. Here we show evidence that the presence of very large aeolian mineral dust particles at Nevado Illimani (Bolivia) is strictly controlled by the occurrence of summer storms in the Bolivian Altiplano. Therefore, based on the snow dust content and its composition of stable water isotopes, we propose a new proxy for information on previous summer storms.
Elizabeth Ruth Thomas, Guisella Gacitúa, Joel B. Pedro, Amy Constance Faith King, Bradley Markle, Mariusz Potocki, and Dorothea Elisabeth Moser
The Cryosphere, 15, 1173–1186, https://doi.org/10.5194/tc-15-1173-2021, https://doi.org/10.5194/tc-15-1173-2021, 2021
Short summary
Short summary
Here we present the first-ever radar and ice core data from the sub-Antarctic islands of Bouvet Island, Peter I Island, and Young Island. These islands have the potential to record past climate in one of the most data-sparse regions on earth. Despite their northerly location, surface melting is generally low, and the upper layer of the ice at most sites is undisturbed. We estimate that a 100 m ice core drilled on these islands could capture climate over the past 100–200 years.
Kirstin Hoffmann, Francisco Fernandoy, Hanno Meyer, Elizabeth R. Thomas, Marcelo Aliaga, Dieter Tetzner, Johannes Freitag, Thomas Opel, Jorge Arigony-Neto, Christian Florian Göbel, Ricardo Jaña, Delia Rodríguez Oroz, Rebecca Tuckwell, Emily Ludlow, Joseph R. McConnell, and Christoph Schneider
The Cryosphere, 14, 881–904, https://doi.org/10.5194/tc-14-881-2020, https://doi.org/10.5194/tc-14-881-2020, 2020
Kévin Fourteau, Patricia Martinerie, Xavier Faïn, Christoph F. Schaller, Rebecca J. Tuckwell, Henning Löwe, Laurent Arnaud, Olivier Magand, Elizabeth R. Thomas, Johannes Freitag, Robert Mulvaney, Martin Schneebeli, and Vladimir Ya. Lipenkov
The Cryosphere, 13, 3383–3403, https://doi.org/10.5194/tc-13-3383-2019, https://doi.org/10.5194/tc-13-3383-2019, 2019
Short summary
Short summary
Understanding gas trapping in polar ice is essential to study the relationship between greenhouse gases and past climates. New data of bubble closure, used in a simple gas-trapping model, show inconsistency with the final air content in ice. This suggests gas trapping is not fully understood. We also use a combination of high-resolution measurements to investigate the effect of polar snow stratification on gas trapping and find that all strata have similar pores, but that some close in advance.
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
Short summary
Short summary
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.
Shugui Hou, Wangbin Zhang, Hongxi Pang, Shuang-Ye Wu, Theo M. Jenk, Margit Schwikowski, and Yetang Wang
The Cryosphere, 13, 1743–1752, https://doi.org/10.5194/tc-13-1743-2019, https://doi.org/10.5194/tc-13-1743-2019, 2019
Short summary
Short summary
The apparent discrepancy between the Holocene δ18O records of the Guliya and the Chongce ice cores may be attributed to a possible misinterpretation of the Guliya ice core chronology.
Sentia Goursaud, Valérie Masson-Delmotte, Vincent Favier, Suzanne Preunkert, Michel Legrand, Bénédicte Minster, and Martin Werner
The Cryosphere, 13, 1297–1324, https://doi.org/10.5194/tc-13-1297-2019, https://doi.org/10.5194/tc-13-1297-2019, 2019
Short summary
Short summary
We report new water stable isotope records from the first highly resolved firn core drilled in Adélie Land and covering 1998–2014. Using an updated database, we show that mean values are in line with the range of coastal values. Statistical analyses show no relationship between our record and local surface air temperature. Atmospheric back trajectories and isotopic simulations suggest that water stable isotopes in Adélie provide a fingerprint of the variability of atmospheric dynamics.
Cited articles
Alley, R. B.: Fabrics in polar ice sheets – Development and prediction, Science, 240, 493–495, 1988.
Alley, R. B.: Flow-law hypotheses for ice-sheet modeling, J. Glaciol., 38, 245–255, 1992.
Alley, R. B., Gow, A. J., Johnsen, S. J., Kipfstuhl, J., Meese, D. A., and Thorsteinsson, T.: Comparison of deep ice cores, Nature, 373, 393–394, https://doi.org/10.1038/373393b0, 1995.
Alley, R. B., Gow, A. J., Meese, D. A., Ftizpatrick, J. J., Waddington, E. D., and Bolzan, J. F.: Grain-scale processes, folding, and stratigraphic disturbance in the GISP2 ice core, J. Geophys. Res., 102, 26819–26830, 1997.
Azuma, N. and Higashi, A.: Formation processes of ice fabric pattern in ice sheets, Ann. Glaciol., 6, 130–134, 1985.
Azuma, N., Wang, Y., Mori, K., Narita, H., Hondoh, T., Shoji, H., and Watanabe, O.: Textures and fabrics in the Dome F (Antarctica) ice core, Ann. Glaciol., 29, 163–168, 1999.
Bamber, J. L., Griggs, J. A., Hurkmans, R. T. W. L., Dowdeswell, J. A., Gogineni, S. P., Howat, I., Mouginot, J., Paden, J., Palmer, S., Rignot, E., and Steinhage, D.: A new bed elevation dataset for Greenland, The Cryosphere, 7, 499–510, https://doi.org/10.5194/tc-7-499-2013, 2013.
Bargmann, S., Seddik, H., and Greve, R.: Computational modeling of flow-induced anisotropy of polar ice for the EDML deep drilling site, Antarctica: the effect of rotation recrystallization and grain boundary migration, Int. J. Numer. Anal. Met.., 36, 892–917, https://doi.org/10.1002/nag.1034, 2011.
Budd, W. and Jacka, T.: A review of ice rheology for ice sheet modelling, Cold Reg. Sci. Technol., 16, 107–144, 1989.
Chappellaz, J., Blunier, T., Kints, S., Dallenbach, A., Barnola, J.-M., Schwander, J., Raynaud, D., and Stauffer, B.: Changes in the atmospheric CH4 gradient between Greenland and Antarctica during the Holocene, J. Geophys. Res.-Atmos., 102, 15987–15997, https://doi.org/10.1029/97JD01017, 1997.
Cuffey, K. M.: Palaeoclimate: Into an ice age, Nature, 431, 133–134, 2004.
Dahl-Jensen, D., Gundestrup, N., Miller, H., Watanabe, O., Johnsen, S. J., Steffensen, J. P., Clausen, H. B., Svensson, A., and Larsen, L. B.: The NorthGRIP deep drilling programme., Ann. Glaciol., 35, 1–4, 2002.
Dahl-Jensen, D., Gundestrup, N., Gorgineni, S. P., and Miller, H.: Basal melt at NorthGRIP modeled from borehole, ice-core and radio-echo sounder observations, Ann. Glaciol., 37, 207–212, 2003.
Dansgaard, W. and Johnsen, S. J.: A flow model and a time scale for the ice core from Camp Century, Greenland, J. Glaciol., 8, 215–223, 1969.
Dansgaard, W., Johnsen, S. J., Clausen, H. B., Dahl-Jensen, D., Gundestrup, N. S., Hammer, C. U., Hvidberg, C. S., Steffensen, J. P., Sveinbjörnsdottir, A. E., Jouzel, J., and Bond, G.: Evidence for general instability of past climate from a 250 kyr ice-core record, Nature, 364, 218–220, 1993.
de la Chapelle, S., Castelnau, O., Lipenkov, V., and Duval, P.: Dynamic recrystallization and texture development in ice as revealed by the study of deep ice cores in Antarctica and Greenland, J. Geophys. Res., 103, 5091–5105, 1998.
Diprinzio, C. L., Wilen, L. A., Alley, R. B., Fitzpatrick, J. J., Spencer, M. K., and Gow, A. J.: Fabric and texture at Siple Dome, Antarctica, J. Glaciol., 51, 281–290, 2005.
Durand, G., Gagliardini, O., Thorsteinsson, T., Svensson, A., Kipfstuhl, J., and Dahl-Jensen, D.: Ice microstructure and fabric: an up to date approach to measure textures, J. Glaciol., 52, 619–630, 2006a.
Durand, G., Weiss, J., Lipenkov, V., Barnola, J. M., Krinner, G., Parrenin, F., Delmonte, B., Ritz, C., Duval, P., Röthlisberger, R., and Bigler, M.: Effect of impurities on grain growth in cold ice sheets, J. Geophys. Res.-Earth, 111, F01015, https://doi.org/10.1029/2005JF000320, 2006b.
Durand, G., Gillet-Chaulet, F., Svensson, A., Gagliardini, O., Kipfstuhl, S., Meyssonnier, J., Parrenin, F., Duval, P., and Dahl-Jensen, D.: Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core, Clim. Past, 3, 155–167, https://doi.org/10.5194/cp-3-155-2007, 2007.
Durand, G., Svensson, A., Persson, A., Gagliardini, O., Gillet-Chaulet, F., Sjolte, J., Montagnat, M., and Dahl-Jensen, D.: Evolution of the texture along the EPICA Dome C ice core, Supp. Issue Low Temperature, Science, 68, 91–106, 2009.
Duval, P. and Lorius, C.: Crystal size and climatic record down to the last ice age from Antarctic ice, Earth Planet. Sc. Lett., 48, 59–64, 1980.
Duval, P., Arnaud, L., Brissaud, O., Montagnat, M., and de La Chapelle, S.: Deformation and recrystallization processes of ice from polar ice sheets, Ann. Glaciol., 30, 83–87, 2000.
Faria, S. H., Weikusat, I., and Azuma, N.: The microstructure of polar ice. Part I: Highlights from ice core research, J. Struct. Geol., 61, 2–20, https://doi.org/10.1016/j.jsg.2013.09.010, 2014.
Gillet-Chaulet, F., Hindmarsh, R. C. A., Corr, H. F. J., King, E. C., and Jenkins, A.: In-situ quantification of ice rheology and direct measurement of the Raymond Effect at Summit, Greenland using a phase-sensitive radar, Geophys. Res. Lett., 38, L24503, https://doi.org/10.1029/2011GL049843, 2011.
Glen, J.: The creep of polycrystalline ice, P. R. Soc. London, A228, 519–538, 1955.
Gow, A. J. and Williamson, T. C.: Rheological implications of the internal structure and crystal fabrics of the West Antarctic ice sheet as revealed by deep core drilling at Byrd Station, Geol. Soc. Am. Bull., 87, 1665–1677, 1976.
Gow, A. J., Meese, D. A., Alley, R. B., Fitzpatrick, J. J., Anandakrishnan, S., Woods, G. A., and Elder, B. C.: Physical and structural properties of the Greenland Ice Sheet Project 2 ice core: A review, J. Geophys. Res.-Oceans, 102, 26559–26575, https://doi.org/10.1029/97JC00165, 1997.
Greve, R. and Blatter, H.: Dynamics of ice sheets and glaciers, Springer Berlin/Heidelberg, 2009.
Herron, S. L. and Langway, C. C. J.: A comparison of ice fabrics and textures at camp Century, Greenland and Bird Station, Antarctica, Ann. Glaciol., 3, 118–124, 1982.
Hvidberg, C. S. and Keller, K., and Gundestrup, N. S.: Mass balance and ice movement along the north-northwest ridge of the Greenland ice sheet at NorthGRIP, Ann. Glaciol., 35, 521–526, 2002.
Kipfstuhl, S., Pauer, F., Kuhs, W. F., and Shoji, H.: Air bubbles and Clathrate hydrates in the transition zone of the NGRIP Deep Ice Core, Geophys. Res. Lett., 28, 591–594, https://doi.org/10.1029/1999GL006094, 2001.
Lipenkov, V.: Air bubbles and air-hydrate crystals in the Vostok ice core, in: Physics of Ice Core Records, edited by: Hondoh, T., 327–358, Hokkaido University Press Sapporo Japan, 2000.
Lipenkov, V. Y., Barkov, N. I., Duval, P., and Pimienta, P.: Crystalline texture of the 2083m ice core at Vostok Station, Antarctica, J. Glaciol., 35, 392–398, 1989.
Lomonaco, R., Albert, M., and Baker, I.: Microstructural evolution of fine-grained layers through the firn column at Summit, Greenland, J. Glaciol., 57, 755–762, 2011.
Montagnat, M., Buiron, D., Arnaud, L., Broquet, A., Schlitz, P., Jacob, R., and Kipfstuhl, S.: Measurements and numerical simulation of fabric evolution along the Talos Dome ice core, Antarctica, Earth and Planetary Science Letters, 357–358, 168–178, https://doi.org/10.1016/j.epsl.2012.09.025, 2012.
Paterson, W. S. B.: Why ice-age ice is sometimes soft, Cold Reg. Sci. Technol., 20, 75–98, 1991.
Paterson, W. S. B.: The physics of glaciers, Pergamon, Oxford, 1994.
Peternell, M., Russell-Head, D., and Wilson, C.: A technique for recording polycrystalline structure and orientation during in situ deformation cycles of rock analogues using an automated fabric analyser, J. Microsc., 242, 181–188, 2011.
Rasmussen, S. O., Abbott, P. M., Blunier, T., Bourne, A. J., Brook, E., Buchardt, S. L., Buizert, C., Chappellaz, J., Clausen, H. B., Cook, E., Dahl-Jensen, D., Davies, S. M., Guillevic, M., Kipfstuhl, S., Laepple, T., Seierstad, I. K., Severinghaus, J. P., Steffensen, J. P., Stowasser, C., Svensson, A., Vallelonga, P., Vinther, B. M., Wilhelms, F., and Winstrup, M.: A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core, Clim. Past, 9, 2713–2730, https://doi.org/10.5194/cp-9-2713-2013, 2013.
Riche, F., Schneebeli, M., and Tschanz, S.: Design-based stereology to quantify structural properties of artificial and natural snow using thin sections, Cold Reg. Sci. Technol., 79–80, 67–74, https://doi.org/10.1016/j.coldregions.2012.03.008, 2012.
Russell-Head, D. S. and Wilson, C. J. L.: Automated fabric analyser system for quartz and ice, J. Glaciol., 24, 117–130, 2001.
Steffensen, J. P., Andersen, K. K., Bigler, M., Clausen, H. B., Dahl-Jensen, D., Fischer, H., Goto-Azuma, K., Hansson, M., Johnsen, S. J., Jouzel, J., Masson-Delmotte, V., Popp, T., Rasmussen, S. O., Röthlisberger, R., Ruth, U., Stauffer, B., Siggaard-Andersen, M.-L., Sveinbjörnsdóttir, Á. E., Svensson, A., and White, J. W. C.: High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years, Science, 321, 680–684, https://doi.org/10.1126/science.1157707, 2008.
Suwa, M., von Fischer, J. C., Bender, M. L., Landais, A., and Brook, E. J.: Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland, J. Geophys. Res.-Atmos., 111, D02101, https://doi.org/10.1029/2005JD006032, 2006.
Svensson, A., Durand, G., Mathiesen, J., and Persson, A., and Dahl-Jensen, D.: Texture of the Upper 1000 m in the GRIP and NorthGRIP Ice Cores, Supp. Issue Low Temperature, Science, 68, 107–113, 2009.
Svensson, A., Bigler, M., Kettner, E., Dahl-Jensen, D., Johnsen, S., Kipfstuhl, S., Nielsen, M., and Steffensen, J. P.: Annual layering in the NGRIP ice core during the Eemian, Clim. Past, 7, 1427–1437, https://doi.org/10.5194/cp-7-1427-2011, 2011.
Thorsteinsson, T., Kipfstuhl, J., and Miller, H.: Textures and fabrics in the GRIP ice core, J. Geophys. Res., 102, 26583–26600, 1997.
Thorsteinsson, T., Waddington, E. D., Taylor, K. C., Alley, R. B., and Blankenship, D. D.: Strain-rate enhancement at Dye 3, Greenland, J. Glaciol., 45, 338–345, 1999.
Wallbrecher, E.: Graphische, rechnerische und statistische, chap. Tektonische und gefügeanalytische Arbeitsweisen, p. 244, Verfahre, Enke, Stuttgart, 1986.
Wang, Y., Thorsteinsson, T., Kipfsuhl, J., Miller, H., Dahl-Jensen, D., and Shoji, H.: A vertical girdle fabric in the NGRIP deep ice core, North Greenland, Ann. Glaciol., 35, 515–520, 2002.
Wang, Y., Kipfstuhl, S., and Azuma, N.: Ice fabrics study in the upper 1500 m of the Dome C deep ice core, East Antarctica, Ann. Glaciol., 37, 97–104, 2003.
Wilson, C., Russell-Head, D., and Sim, H.: The application of an automated fabric analyzer system to the textural evolution of folded ice layers in shear zones, Ann. Glaciol., 37, 7–17, 2003.
