Articles | Volume 15, issue 7
https://doi.org/10.5194/tc-15-3507-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-15-3507-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 Jul 2021
Research article |
| 28 Jul 2021
| 28 Jul 2021
Acoustic velocity measurements for detecting the crystal orientation fabrics of a temperate ice core
Sebastian Hellmann
CORRESPONDING AUTHOR
Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
Institute of Geophysics, ETH Zurich, Zurich, Switzerland
Melchior Grab
Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
Institute of Geophysics, ETH Zurich, Zurich, Switzerland
Johanna Kerch
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
GZG Computational Geoscience, Georg-August University, Göttingen, Germany
Henning Löwe
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Andreas Bauder
Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland
Ilka Weikusat
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany
Department of Geosciences, Eberhard Karls University, Tübingen, Germany
Hansruedi Maurer
Institute of Geophysics, ETH Zurich, Zurich, Switzerland
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We have developed a novel procedure for glacier thickness estimations that combines traditional glaciological modeling constraints with ground-truth data, for example, those obtained with ground-penetrating radar (GPR) measurements. This procedure is very useful for determining ice volume when only limited data are available. Furthermore, we outline a strategy for acquiring GPR data on glaciers, such that the cost/benefit ratio is optimized.
Isabelle Gouttevin, Moritz Langer, Henning Löwe, Julia Boike, Martin Proksch, and Martin Schneebeli
The Cryosphere, 12, 3693–3717, https://doi.org/10.5194/tc-12-3693-2018, https://doi.org/10.5194/tc-12-3693-2018, 2018
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Snow insulates the ground from the cold air in the Arctic winter, majorly affecting permafrost. This insulation depends on snow characteristics and is poorly quantified. Here, we characterize it at a carbon-rich permafrost site, using a recent technique that retrieves the 3-D structure of snow and its thermal properties. We adapt a snowpack model enabling the simulation of this insulation over a whole winter. We estimate that local snow variations induce up to a 6 °C spread in soil temperatures.
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
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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.
Ghislain Picard, Melody Sandells, and Henning Löwe
Geosci. Model Dev., 11, 2763–2788, https://doi.org/10.5194/gmd-11-2763-2018, https://doi.org/10.5194/gmd-11-2763-2018, 2018
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The Snow Microwave Radiative Transfer (SMRT) is a novel model developed to calculate how microwaves are scattered and emitted by snow. The model is built from separate, interconnecting modules to make it easy to compare different aspects of the theory. SMRT is the first model to allow a choice of how to represent the microstructure of the snow, which is extremely important, and has been used to unite multiple previous studies. This model will ultimately be used to observe snow from space.
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
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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.
Florian Amann, Valentin Gischig, Keith Evans, Joseph Doetsch, Reza Jalali, Benoît Valley, Hannes Krietsch, Nathan Dutler, Linus Villiger, Bernard Brixel, Maria Klepikova, Anniina Kittilä, Claudio Madonna, Stefan Wiemer, Martin O. Saar, Simon Loew, Thomas Driesner, Hansruedi Maurer, and Domenico Giardini
Solid Earth, 9, 115–137, https://doi.org/10.5194/se-9-115-2018, https://doi.org/10.5194/se-9-115-2018, 2018
Pascal Bohleber, Helene Hoffmann, Johanna Kerch, Leo Sold, and Andrea Fischer
The Cryosphere, 12, 401–412, https://doi.org/10.5194/tc-12-401-2018, https://doi.org/10.5194/tc-12-401-2018, 2018
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In this study we use an existing ice cave at Chli Titlis (3030 m, central Switzerland) to obtain direct access to ice at the glacier base. Using standard glaciological tools as well as the analysis of the isotopic and physical properties we demonstrate that stagnant cold ice conditions still exist fairly unchanged more than 25 years after a pioneering exploration. Our radiocarbon dating of the basal ice indicates that Chli Titlis has likely been ice-covered for about the last 5000 years.
Valentin Samuel Gischig, Joseph Doetsch, Hansruedi Maurer, Hannes Krietsch, Florian Amann, Keith Frederick Evans, Morteza Nejati, Mohammadreza Jalali, Benoît Valley, Anne Christine Obermann, Stefan Wiemer, and Domenico Giardini
Solid Earth, 9, 39–61, https://doi.org/10.5194/se-9-39-2018, https://doi.org/10.5194/se-9-39-2018, 2018
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
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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.
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
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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.
Melchior Grab, Beatriz Quintal, Eva Caspari, Hansruedi Maurer, and Stewart Greenhalgh
Solid Earth, 8, 255–279, https://doi.org/10.5194/se-8-255-2017, https://doi.org/10.5194/se-8-255-2017, 2017
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Hot fluids and hydraulically conductive rock formations are essential for the accessibility of geothermal resources. We use numerical modeling techniques to investigate how seismic waves change their shape in presence of these factors. We demonstrate how to parameterize such models depending on the local geology and as a function of depth. Finally, we show how the attenuation, i.e. the energy loss of the wave, can be indicative for permeable rock fractures saturated with a fluid of specific type.
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
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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.
Quirine Krol and Henning Löwe
The Cryosphere, 10, 2847–2863, https://doi.org/10.5194/tc-10-2847-2016, https://doi.org/10.5194/tc-10-2847-2016, 2016
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Optical and microwave modelling of snow involve different metrics of "grain size" and existing, empirical relations between them are subject to considerable scatter. We introduce two objectively defined metrics of grain shape, derived from micro-computed tomography images, that lead to improved statistical models between the different grain metrics. Our results allow to assess the relevance of grain shape in both fields on common grounds.
Silvan Leinss, Henning Löwe, Martin Proksch, Juha Lemmetyinen, Andreas Wiesmann, and Irena Hajnsek
The Cryosphere, 10, 1771–1797, https://doi.org/10.5194/tc-10-1771-2016, https://doi.org/10.5194/tc-10-1771-2016, 2016
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Four years of anisotropy measurements of seasonal snow are presented in the paper. The anisotropy was measured every 4 h with a ground-based polarimetric radar. An electromagnetic model has been developed to measured the anisotropy with radar instruments from ground and from space. The anisotropic permittivity was derived with Maxwell–Garnett-type mixing formulas which are shown to be equivalent to series expansions of the permittivity tensor based on spatial correlation function of snow.
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
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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.
H. Löwe and G. Picard
The Cryosphere, 9, 2101–2117, https://doi.org/10.5194/tc-9-2101-2015, https://doi.org/10.5194/tc-9-2101-2015, 2015
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The paper establishes a theoretical link between two widely used microwave models for snow. The scattering formulations from both models are unified by reformulating their microstructure models in a common framework. The results show that the scattering formulations can be considered equivalent, if exactly the same microstructure model is used. The paper also provides a method to measure a hitherto unknown input parameter for the microwave models from tomography images of snow.
M. Proksch, C. Mätzler, A. Wiesmann, J. Lemmetyinen, M. Schwank, H. Löwe, and M. Schneebeli
Geosci. Model Dev., 8, 2611–2626, https://doi.org/10.5194/gmd-8-2611-2015, https://doi.org/10.5194/gmd-8-2611-2015, 2015
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The measurement of snow properties on global scale relies on microwave remote sensing data. The interpretation of the data is however challenging. Here we introduce MEMLS3&a, an extension of the snow emission model MEMLS, to include a backscatter model for active microwave remote sensing. In MEMLS3&a, snow input parameters can be derived by objective measurement methods, which avoids fitting the scattering efficiency of snow. The model is validated with combined active and passive measurements.
J. Gabbi, M. Huss, A. Bauder, F. Cao, and M. Schwikowski
The Cryosphere, 9, 1385–1400, https://doi.org/10.5194/tc-9-1385-2015, https://doi.org/10.5194/tc-9-1385-2015, 2015
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Light-absorbing impurities in snow and ice increase the absorption of solar radiation and thus enhance melting. We investigated the effect of Saharan dust and black carbon on the mass balance of an Alpine glacier over 1914-2014. Snow impurities increased melt by 15-19% depending on the location on the glacier. From the accumulation area towards the equilibrium line, the effect of impurities increased as more frequent years with negative mass balance led to a re-exposure of dust-enriched layers.
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
S. Schleef, H. Löwe, and M. Schneebeli
The Cryosphere, 8, 1825–1838, https://doi.org/10.5194/tc-8-1825-2014, https://doi.org/10.5194/tc-8-1825-2014, 2014
M. Montagnat, N. Azuma, D. Dahl-Jensen, J. Eichler, S. Fujita, F. Gillet-Chaulet, S. Kipfstuhl, D. Samyn, A. Svensson, and I. Weikusat
The Cryosphere, 8, 1129–1138, https://doi.org/10.5194/tc-8-1129-2014, https://doi.org/10.5194/tc-8-1129-2014, 2014
H. Löwe, F. Riche, and M. Schneebeli
The Cryosphere, 7, 1473–1480, https://doi.org/10.5194/tc-7-1473-2013, https://doi.org/10.5194/tc-7-1473-2013, 2013
J. Kropáček, N. Neckel, and A. Bauder
The Cryosphere Discuss., https://doi.org/10.5194/tcd-7-3261-2013, https://doi.org/10.5194/tcd-7-3261-2013, 2013
Preprint withdrawn
Related subject area
Discipline: Glaciers | Subject: Ice Cores
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
Review article: Melt-Affected Ice Cores for (Sub-)Polar Research in a Warming World
Early Holocene ice on the Begguya plateau (Mt. Hunter, Alaska) revealed by ice core 14C age constraints
Impact of subsurface crevassing on the depth-age relationship of high-alpine ice cores extracted at Col du Dôme between 1994 and 2012
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
Brief communication: New evidence further constraining Tibetan ice core chronologies to the Holocene
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
Apparent discrepancy of Tibetan ice core δ18O records may be attributed to misinterpretation of chronology
Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains
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
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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
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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
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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.
Dorothea Elisabeth Moser, Elizabeth R. Thomas, Christoph Nehrbass-Ahles, Anja Eichler, and Eric Wolff
EGUsphere, https://doi.org/10.5194/egusphere-2023-1939, https://doi.org/10.5194/egusphere-2023-1939, 2023
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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 for analysing 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.
Ling Fang, Theo M. Jenk, Dominic Winski, Karl Kreutz, Hanna L. Brooks, Emma Erwin, Erich Osterberg, Seth Campbell, Cameron Wake, and Margit Schwikowski
The Cryosphere, 17, 4007–4020, https://doi.org/10.5194/tc-17-4007-2023, https://doi.org/10.5194/tc-17-4007-2023, 2023
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Understanding the behavior of ocean–atmosphere teleconnections in the North Pacific during warm intervals can aid in predicting future warming scenarios. However, majority ice core records from Alaska–Yukon region only provide data for the last few centuries. This study introduces a continuous chronology for Denali ice core from Begguya, Alaska, using multiple dating methods. The early-Holocene-origin Denali ice core will facilitate future investigations of hydroclimate in the North Pacific.
Susanne Preunkert, Pascal Bohleber, Michel Legrand, Hubertus Fischer, Adrien Gilbert, Tobias Erhardt, Roland Purtschert, Lars Zipf, Astrid Waldner, and Joseph R. McConnell
The Cryosphere Discuss., https://doi.org/10.5194/tc-2022-259, https://doi.org/10.5194/tc-2022-259, 2023
Revised manuscript accepted for TC
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Being close to European pollution source regions makes ice cores from Alpine glaciers important to reconstruct past anthropogenic changes over Europe. Three ice cores covering the 20th century were extracted at the same place at the Col du Dôme (4250 masl, French Alps) in 1994, 2004, and 2012. Combining chemical profiles, bomb test markers and 210Pb profiles, used as footprints of crevasses, allowed to highlight changes over time of the depth-age characteristics at an Alpine drill site.
Giyoon Lee, Jinho Ahn, Hyeontae Ju, Florian Ritterbusch, Ikumi Oyabu, Christo Buizert, Songyi Kim, Jangil Moon, Sambit Ghosh, Kenji Kawamura, Zheng-Tian Lu, Sangbum Hong, Chang Hee Han, Soon Do Hur, Wei Jiang, and Guo-Min Yang
The Cryosphere, 16, 2301–2324, https://doi.org/10.5194/tc-16-2301-2022, https://doi.org/10.5194/tc-16-2301-2022, 2022
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Blue-ice areas (BIAs) have several advantages for reconstructing past climate. However, the complicated ice flow in the area hinders constraining the age. We applied state-of-the-art techniques and found that the ages cover the last deglaciation period. Our study demonstrates that the BIA in northern Victoria Land may help reconstruct the past climate during the termination of the last glacial period.
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
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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.
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
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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.
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
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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
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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
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
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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.
Shugui Hou, Theo M. Jenk, Wangbin Zhang, Chaomin Wang, Shuangye Wu, Yetang Wang, Hongxi Pang, and Margit Schwikowski
The Cryosphere, 12, 2341–2348, https://doi.org/10.5194/tc-12-2341-2018, https://doi.org/10.5194/tc-12-2341-2018, 2018
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We present multiple lines of evidence indicating that the Chongce ice cores drilled from the northwestern Tibetan Plateau reaches back only to the early Holocene. This result is at least, 1 order of magnitude younger than the nearby Guliya ice core (~30 km away from the Chongce ice core drilling site) but similar to other Tibetan ice cores. Thus it is necessary to explore multiple dating techniques to confirm the age ranges of the Tibetan ice cores.
Cited articles
Aki, K. and Richards, P. G.: Quantitative Seismology,
Quantitative Seismology, edited by: Aki, K. and Richards, P. G..
University Science Books, 2nd Edn., ISBN 0-935702-96-2, 704pp, 2002. a
Alley, R. B.: Fabrics in Polar Ice Sheets: Development and Prediction, Science,
240, 493–495, 1988. a
Alley, R. B.: Flow-Law Hypotheses for Ice-Sheet Modeling, J.
Glaciol., 38, 245–256, 1992. a
Anandakrishnan, S., Fltzpatrick, J. J., Alley, R. B., Gow, A. J., and Meese,
D. A.: Shear-Wave Detection of Asymmetric c-Axis Fabrics in the GISP2 Ice
Core, Greenland, J. Glaciol., 40, 491–496,
https://doi.org/10.3189/S0022143000012363, 1994. a
Azuma, N.: A Flow Law for Anisotropic Ice and Its Application to Ice Sheets,
Earth Planet Sc. Lett., 128, 601–614,
https://doi.org/10.1016/0012-821X(94)90173-2, 1994. a
Azuma, N. and Higashi, A.: Mechanical Properties of Dye 3 Greenland
Deep Ice Cores, Ann. Glaciol., 5, 1–8, 1984. a
Bennett, H. F.: An Investigation into Velocity Anisotropy through Measurements
of Ultrasonica Wave Velocities in Snow and Ice Cores from Greenland and
Antarctica(Investigation into Velocity Anisotropy through
Measurements of Ultrasonic Wave Velocities in Snow and Ice Cores from
Greenland and Antarctica), PhD Thesis, University of
Wisconsin-Madison, 1968. a
Bentley, C. R.: Seismic-Wave Velocities in Anisotropic Ice: A Comparison of
Measured and Calculated Values in and around the Deep Drill Hole at Byrd
Station, Antarctica, J. Geophys. Res., 77,
4406–4420, https://doi.org/10.1029/JB077i023p04406, 1972. a, b
Bentley, C. R.: Advances in Geophysical Exploration of Ice Sheets and Glaciers,
J. Glaciol., 15, 113–135, https://doi.org/10.3189/S0022143000034328, 1975. a
Binder, T., Garbe, C. S., Wagenbach, D., Freitag, J., and Kipfstuhl, S.:
Extraction and Parametrization of Grain Boundary Networks in Glacier Ice,
Using a Dedicated Method of Automatic Image Analysis, J. Microsc.,
250, 130–141, https://doi.org/10.1111/jmi.12029, 2013. a
Blankenship, D. D. and Bentley, C. R.: The Crystalline Fabric of Polar Ice
Sheets Inferred from Seismic Anisotropy, IAHS Publ., 170, 17–28, 1987. a
Brisbourne, A. M., Martín, C., Smith, A. M., Baird, A. F., Kendall, J. M.,
and Kingslake, J.: Constraining Recent Ice Flow History at Korff Ice
Rise, West Antarctica, Using Radar and Seismic Measurements of
Ice Fabric, J. Geophys. Res.-Earth, 124/1, 175–194,
https://doi.org/10.1029/2018JF004776, 2019. a
Budd, W. F. and Jacka, T. H.: A Review of Ice Rheology for Ice Sheet Modelling,
Cold Reg. Sci. Technol., 16, 107–144,
https://doi.org/10.1016/0165-232X(89)90014-1, 1989. a
Cuffey, K. M. and Paterson, W. S. B.: The Physics of Glaciers, 4th Edn., Elsevier,
Amsterdam, 2010. a
Diez, A. and Eisen, O.: Seismic wave propagation in anisotropic ice – Part 1: Elasticity tensor and derived quantities from ice-core properties, The Cryosphere, 9, 367–384, https://doi.org/10.5194/tc-9-367-2015, 2015. a, b, c
Diez, A., Eisen, O., Weikusat, I., Eichler, J., Hofstede, C., Bohleber, P.,
Bohlen, T., and Polom, U.: Influence of Ice Crystal Anisotropy on Seismic
Velocity Analysis, Ann. Glaciol., 55, 97–106,
https://doi.org/10.3189/2014AoG67A002, 2014. a
Diez, A., Eisen, O., Hofstede, C., Lambrecht, A., Mayer, C., Miller, H., Steinhage, D., Binder, T., and Weikusat, I.: Seismic wave propagation in anisotropic ice – Part 2: Effects of crystal anisotropy in geophysical data, The Cryosphere, 9, 385–398, https://doi.org/10.5194/tc-9-385-2015, 2015. a, b
Drews, R., Eisen, O., Steinhage, D., Weikusat, I., Kipfstuhl, S., and Wilhelms,
F.: Potential Mechanisms for Anisotropy in Ice-Penetrating Radar Data,
J. Glaciol., 58, 613–624, https://doi.org/10.3189/2012JoG11J114, 2012. a
Eichler, J.: C-Axis Analysis of the NEEM Ice Core – An
Approach Based on Digital Image Processing, Diploma Thesis, Freie
Universität Berlin, 2013. a
Faria, S. H., Weikusat, I., and Azuma, N.: The Microstructure of Polar Ice.
Part II: State of the Art, J. Struct. Geol., 61, 21–49,
https://doi.org/10.1016/j.jsg.2013.11.003, 2014. a, b
Fourteau, K., Martinerie, P., Faïn, X., Schaller, C. F., Tuckwell, R. J., Löwe, H., Arnaud, L., Magand, O., Thomas, E. R., Freitag, J., Mulvaney, R., Schneebeli, M., and Lipenkov, V. Ya.: Multi-tracer study of gas trapping in an East Antarctic ice core, The Cryosphere, 13, 3383–3403, https://doi.org/10.5194/tc-13-3383-2019, 2019. a
Freitag, J., Wilhelms, F., and Kipfstuhl, S.: Microstructure-Dependent
Densification of Polar Firn Derived from X-Ray Microtomography, J.
Glaciol., 50, 243–250, https://doi.org/10.3189/172756504781830123, 2004. a
Gerling, B., Löwe, H., and van Herwijnen, A.: Measuring the Elastic
Modulus of Snow, Geophys. Res. Lett., 44, 11088–11096,
https://doi.org/10.1002/2017GL075110, 2017. a, b
Gillet-Chaulet, F., Gagliardini, O., Meyssonnier, J., Montagnat, M., and
Castelnau, O.: A User-Friendly Anisotropic Flow Law for Ice-Sheet Modeling,
J. Glaciol., 51, 3–14, https://doi.org/10.3189/172756505781829584, 2005. a
Graham, F. S., Morlighem, M., Warner, R. C., and Treverrow, A.: Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models, The Cryosphere, 12, 1047–1067, https://doi.org/10.5194/tc-12-1047-2018, 2018. a
Gusmeroli, A., Pettit, E. C., Kennedy, J. H., and Ritz, C.: The Crystal Fabric
of Ice from Full-Waveform Borehole Sonic Logging: Borehole sonic logging in
ice sheets, J. Geophys. Res.-Earth, 117, F03021,
https://doi.org/10.1029/2012JF002343, 2012. a, b
Hagenmuller, P., Chambon, G., Lesaffre, B., Flin, F., and Naaim, M.:
Energy-Based Binary Segmentation of Snow Microtomographic Images, J.
Glaciol., 59, 859–873, https://doi.org/10.3189/2013JoG13J035, 2013. a
Hellmann, S., Kerch, J., Eichler, J., Jansen, D., Weikusat, I., Schwikowski,
M., Bauder, A., and Maurer, H.: Crystal C-Axes Measurements (Fabric
Analyser G50) of Ice Core Samples Collected from the Temperate Alpine
Ice Core Rhone_2017, PANGAEA, https://doi.org/10.1594/PANGAEA.888518, 2018a. a
Hellmann, S., Kerch, J., Eichler, J., Jansen, D., Weikusat, I., Schwikowski,
M., Bauder, A., and Maurer, H.: Large Area Scan Macroscope Images of Ice
Core Samples Collected from the Temperate Alpine Ice Core
Rhone_2017, PANGAEA, https://doi.org/10.1594/PANGAEA.888517, 2018b. a
Hellmann, S., Grab, M., Jaggi, M., Löwe, H., and Bauder, A.: Acoustic
Ultrasound Measurements on Ice Core Samples from Rhonegletscher, ETH
Zurich, https://doi.org/10.3929/ethz-b-000453859, 2020. a
Hill, R.: The Elastic Behaviour of a Crystalline Aggregate, Proc. Phys. Soc. A, 65, 349–354,
https://doi.org/10.1088/0370-1298/65/5/307, 1952. a
Hooke, R. L. and Hudleston, P. J.: Ice Fabrics in a Vertical Flow
Plane, Barnes Ice Cap, Canada, J. Glaciol., 25, 195–214,
https://doi.org/10.3189/S0022143000010443, 1980. a, b
Jordan, T. M., Schroeder, D. M., Castelletti, D., Li, J., and Dall, J.: A
Polarimetric Coherence Method to Determine Ice Crystal Orientation
Fabric From Radar Sounding: Application to the NEEM Ice Core
Region, IEEE T. Geosci. Remote, 57, 8641–8657,
https://doi.org/10.1109/TGRS.2019.2921980, 2019. a
Kluskiewicz, D., Waddington, E. D., Anandakrishnan, S., Voigt, D. E., Matsuoka,
K., and McCarthy, M. P.: Sonic Methods for Measuring Crystal Orientation
Fabric in Ice, and Results from the West Antarctic Ice Sheet (WAIS)
Divide, J. Glaciol., 63, 603–617, https://doi.org/10.1017/jog.2017.20,
2017. a
Kohnen, H.: The Temperature Dependence of Seismic Waves in Ice, J.
Glaciol., 13, 144–147, 1974. a
Krischke, A., Oechsner, U., and Kipfstuhl, S.: Rapid Microstructure
Analysis of Polar Ice Cores, Optik & Photonik, 10, 32–35,
https://doi.org/10.1002/opph.201500016, 2015. a
Langway, C. C., Shoji, H., and Azuma, N.: Crystal Size and Orientation
Patterns in the Wisconsin-Age Ice from Dye 3, Greenland,
Ann. Glaciol., 10, 109–115, https://doi.org/10.3189/S0260305500004262, 1988. a
Mainprice, D., Hielscher, R., and Schaeben, H.: Calculating Anisotropic
Physical Properties from Texture Data Using the MTEX Open-Source Package,
Geol. Soc. Spec. Publ., 360, 175–192,
https://doi.org/10.1144/SP360.10, 2011. a, b
Matsuoka, K., Furukawa, T., Fujita, S., Maeno, H., Uratsuka, S., Naruse, R.,
and Watanabe, O.: Crystal Orientation Fabrics within the Antarctic Ice
Sheet Revealed by a Multipolarization Plane and Dual-Frequency Radar Survey,
J. Geophys. Res.-Sol. Ea., 108, 2499,
https://doi.org/10.1029/2003JB002425, 2003. a
Maurel, A., Lund, F., and Montagnat, M.: Propagation of Elastic Waves through
Textured Polycrystals: Application to Ice, P. Roy. Soc. A, 471, 20140988,
https://doi.org/10.1098/rspa.2014.0988, 2015. a, b
Maurel, A., Mercier, J.-F., and Montagnat, M.: Critical investigation of calculation methods for the elastic velocities in anisotropic ice polycrystals, The Cryosphere, 10, 3063–3070, https://doi.org/10.5194/tc-10-3063-2016, 2016. a
Mikesell, T., van Wijk, K., Otheim, L., Marshall, H.-P., and Kurbatov, A.:
Laser Ultrasound Observations of Mechanical Property Variations in
Ice Cores, Geosciences, 7, 47, https://doi.org/10.3390/geosciences7030047, 2017. a
Monz, M. E., Hudleston, P. J., Prior, D. J., Michels, Z., Fan, S., Negrini, M., Langhorne, P. J., and Qi, C.: Full crystallographic orientation (c and a axes) of warm, coarse-grained ice in a shear-dominated setting: a case study, Storglaciären, Sweden, The Cryosphere, 15, 303–324, https://doi.org/10.5194/tc-15-303-2021, 2021. a, b, c
Nanthikesan, S. and Sunder, S.: Anisotropic Elasticity of Polycrystalline Ice
Ih, Cold Reg. Sci. Technol., 22, 149–169,
https://doi.org/10.1016/0165-232X(94)90026-4, 1994. a
Nguyen, X. V.: The Spherical K-Means Algorithm,
MATLAB Central File Exchange, available at:
https://ch.mathworks.com/matlabcentral/fileexchange/32987-the-spherical-k-means-algorithm, last access: 23 July 2020.
a
Peternell, M., Kohlmann, F., Wilson, C. J., Seiler, C., and Gleadow, A. J.: A
New Approach to Crystallographic Orientation Measurement for Apatite Fission
Track Analysis: Effects of Crystal Morphology and Implications for
Automation, Chem. Geol., 265, 527–539,
https://doi.org/10.1016/j.chemgeo.2009.05.021, 2009. a, b
Pettit, E. C., Thorsteinsson, T., Jacobson, H. P., and Waddington, E. D.: The
Role of Crystal Fabric in Flow near an Ice Divide, J. Glaciol., 53,
277–288, https://doi.org/10.3189/172756507782202766, 2007. a
Picotti, S., Vuan, A., Carcione, J. M., Horgan, H. J., and Anandakrishnan, S.:
Anisotropy and Crystalline Fabric of Whillans Ice Stream (West
Antarctica) Inferred from Multicomponent Seismic Data, J.
Geophys. Res.-Sol. Ea., 120, 4237–4262,
https://doi.org/10.1002/2014JB011591, 2015. a
Placidi, L., Greve, R., Seddik, H., and Faria, S. H.: Continuum-Mechanical,
Anisotropic Flow Model for Polar Ice Masses, Based on an Anisotropic
Flow Enhancement Factor, Continuum Mech. Therm., 22,
221–237, https://doi.org/10.1007/s00161-009-0126-0, 2010. a
Schwikowski, M., Jenk, T. M., Stampfli, D., and Stampfli, F.: A New Thermal
Drilling System for High-Altitude or Temperate Glaciers, Ann.
Glaciol., 55, 131–136, https://doi.org/10.3189/2014AoG68A024, 2014. a
Selvadurai, P. A.: Laboratory Insight Into Seismic Estimates of Energy
Partitioning During Dynamic Rupture: An Observable Scaling Breakdown,
J. Geophys. Res.-Sol. Ea., 124, 11350–11379,
https://doi.org/10.1029/2018JB017194, 2019. a
Torquato, S.: Random Heterogeneous Materials: Microstructure and Macroscopic
Properties, 16, in: Interdisciplinary Applied Mathematics, Springer,
New York, 2002. a
Voigt, W.: Lehrbuch Der Kristallphysik: Mit Ausschluss Der
Kristalloptik, vol. 12 of Bibliotheca Mathematica
Teubneriana, Teubner, Leipzig, Berlin, 1st Edn., 1910. a
Wallbrecher, E.: Tektonische Und Gefügeanalytische Arbeitsweisen:
Graphische, Rechnerische Und Statistische Verfahren, Enke, Stuttgart,
1986. a
Wilhelms, F.: Explaining the Dielectric Properties of Firn as a
Density-and-Conductivity Mixed Permittivity (DECOMP), Geophys.
Res. Lett, 32, L16501, https://doi.org/10.1029/2005GL022808, 2005. a
Wilhelms, F., Kipfstuhl, J., Miller, H., Heinloth, K., and Firestone, J.:
Precise Dielectric Profiling of Ice Cores: A New Device with Improved
Guarding and Its Theory, J. Glaciol., 44, 171–174,
https://doi.org/10.3189/S002214300000246X, 1998. a
Williamson, P. R. and Worthington, M. H.: Resolution Limits in Ray Tomography
Due to Wave Behavior: Numerical Experiments, Geophysics, 58, 727–735,
https://doi.org/10.1190/1.1443457, 1993. a
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.
In this study, we analyse whether ultrasonic measurements on ice core samples could be employed...
