Articles | Volume 15, issue 8
https://doi.org/10.5194/tc-15-4117-2021
© 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-15-4117-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
27 Aug 2021
Research article |
| 27 Aug 2021
| 27 Aug 2021
Rapid and accurate polarimetric radar measurements of ice crystal fabric orientation at the Western Antarctic Ice Sheet (WAIS) Divide ice core site
Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, UK
Carlos Martín
British Antarctic Survey, Natural Environment Research Council, Cambridge CB3 0ET, UK
Poul Christoffersen
Scott Polar Research Institute, University of Cambridge, Cambridge CB2 1ER, UK
Dustin M. Schroeder
Department of Geophysics, Stanford University, Stanford, CA 94305, USA
Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
Slawek M. Tulaczyk
Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA
Eliza J. Dawson
Department of Geophysics, Stanford University, Stanford, CA 94305, USA
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Álvaro Arenas-Pingarrón, Alex M. Brisbourne, Carlos Martín, Hugh F. J. Corr, Carl Robinson, Tom A. Jordan, and Paul V. Brennan
EGUsphere, https://doi.org/10.5194/egusphere-2025-1068, https://doi.org/10.5194/egusphere-2025-1068, 2025
This preprint is open for discussion and under review for The Cryosphere (TC).
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Synthetic Aperture Radar (SAR) imaging is essential for deep englacial observations. Each pixel is formed by averaging the radar echoes within an antenna beamwidth, but the echo diversity is lost after the average. We improve the SAR interpretation if three sub-images are formed with different sub-beamwidths: each is coloured in red, green, or blue, and they are overlapped, creating a coloured image. Interpreters will better identify the slopes of internal layers, crevasses, and layer roughness.
Frédéric Parrenin, Ailsa Chung, and Carlos Martín
EGUsphere, https://doi.org/10.5194/egusphere-2024-3411, https://doi.org/10.5194/egusphere-2024-3411, 2025
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We developed a new numerical age solver for a pseudo-steady flow tube of an ice sheet. Thanks to a new coordinate system which tracks the trajectories and a change of the time variable, our scheme combines the advantages of Eulerian and Lagrangian schemes: no numerical diffusion and no dilution of tracers. Our model is so fast that it is easy to optimize its parameters. Our model is made available to the ice sheet community as an easy to use open-source software coded in python.
Yu Wang, Chen Zhao, Rupert Gladstone, Thomas Zwinger, Benjamin K. Galton-Fenzi, and Poul Christoffersen
The Cryosphere, 18, 5117–5137, https://doi.org/10.5194/tc-18-5117-2024, https://doi.org/10.5194/tc-18-5117-2024, 2024
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Our research delves into the future evolution of Antarctica's Wilkes Subglacial Basin (WSB) and its potential contribution to sea level rise, focusing on how basal melt is implemented at the grounding line in ice flow models. Our findings suggest that these implementation methods can significantly impact the magnitude of future ice loss projections. Under a high-emission scenario, the WSB ice sheet could undergo massive and rapid retreat between 2200 and 2300.
Robert G. Bingham, Julien A. Bodart, Marie G. P. Cavitte, Ailsa Chung, Rebecca J. Sanderson, Johannes C. R. Sutter, Olaf Eisen, Nanna B. Karlsson, Joseph A. MacGregor, Neil Ross, Duncan A. Young, David W. Ashmore, Andreas Born, Winnie Chu, Xiangbin Cui, Reinhard Drews, Steven Franke, Vikram Goel, John W. Goodge, A. Clara J. Henry, Antoine Hermant, Benjamin H. Hills, Nicholas Holschuh, Michelle R. Koutnik, Gwendolyn J.-M. C. Leysinger Vieli, Emma J. Mackie, Elisa Mantelli, Carlos Martín, Felix S. L. Ng, Falk M. Oraschewski, Felipe Napoleoni, Frédéric Parrenin, Sergey V. Popov, Therese Rieckh, Rebecca Schlegel, Dustin M. Schroeder, Martin J. Siegert, Xueyuan Tang, Thomas O. Teisberg, Kate Winter, Shuai Yan, Harry Davis, Christine F. Dow, Tyler J. Fudge, Tom A. Jordan, Bernd Kulessa, Kenichi Matsuoka, Clara J. Nyqvist, Maryam Rahnemoonfar, Matthew R. Siegfried, Shivangini Singh, Verjan Višnjević, Rodrigo Zamora, and Alexandra Zuhr
EGUsphere, https://doi.org/10.5194/egusphere-2024-2593, https://doi.org/10.5194/egusphere-2024-2593, 2024
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The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative to work together on this archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica, and how this will be used to reconstruct past and predict future ice and climate behaviour.
Ole Zeising, Álvaro Arenas-Pingarrón, Alex M. Brisbourne, and Carlos Martín
EGUsphere, https://doi.org/10.5194/egusphere-2024-2519, https://doi.org/10.5194/egusphere-2024-2519, 2024
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Ice crystal orientation influence how glacier ice deforms. Radar polarimetry is commonly used to study the bulk ice crystal orientation, but the often used coherence method only provides information of the shallow ice in fast-flowing areas. This study shows that reducing the bandwidth of high-bandwidth radar data significantly enhances the depth limit of the coherence method. This improvement helps us to better understand ice dynamics in fast-flowing ice streams.
Nanna B. Karlsson, Dustin M. Schroeder, Louise Sandberg Sørensen, Winnie Chu, Jørgen Dall, Natalia H. Andersen, Reese Dobson, Emma J. Mackie, Simon J. Köhn, Jillian E. Steinmetz, Angelo S. Tarzona, Thomas O. Teisberg, and Niels Skou
Earth Syst. Sci. Data, 16, 3333–3344, https://doi.org/10.5194/essd-16-3333-2024, https://doi.org/10.5194/essd-16-3333-2024, 2024
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In the 1970s, more than 177 000 km of observations were acquired from airborne radar over the Greenland ice sheet. The radar data contain information on not only the thickness of the ice, but also the properties of the ice itself. This information was recorded on film rolls and subsequently stored. In this study, we document the digitization of these film rolls that shed new and unprecedented detailed light on the Greenland ice sheet 50 years ago.
Gavin Piccione, Terrence Blackburn, Paul Northrup, Slawek Tulaczyk, and Troy Rasbury
EGUsphere, https://doi.org/10.5194/egusphere-2024-1359, https://doi.org/10.5194/egusphere-2024-1359, 2024
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Growth of microorganisms in the Southern Ocean is limited by low iron levels. Iron delivered from beneath the Antarctic Ice Sheet is one agent that fertilizes these ecosystems, but it is unclear how this nutrient source changes through time. Here, we measured the age and chemistry of a rock that records the iron concentration of Antarctic basal water. We show that increased dissolution of iron from rocks below the ice sheet can substantially enhance iron discharge during cold climate periods.
Ricardo Garza-Girón and Slawek M. Tulaczyk
The Cryosphere, 18, 1207–1213, https://doi.org/10.5194/tc-18-1207-2024, https://doi.org/10.5194/tc-18-1207-2024, 2024
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By analyzing temperature time series over more than 20 years, we have found a discrepancy between the 2 m temperature values reported by the ERA5 reanalysis and the automatic weather stations in the McMurdo Dry Valleys, Antarctica.
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
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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.
Ailsa Chung, Frédéric Parrenin, Daniel Steinhage, Robert Mulvaney, Carlos Martín, Marie G. P. Cavitte, David A. Lilien, Veit Helm, Drew Taylor, Prasad Gogineni, Catherine Ritz, Massimo Frezzotti, Charles O'Neill, Heinrich Miller, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 17, 3461–3483, https://doi.org/10.5194/tc-17-3461-2023, https://doi.org/10.5194/tc-17-3461-2023, 2023
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We combined a numerical model with radar measurements in order to determine the age of ice in the Dome C region of Antarctica. Our results show that at the current ice core drilling sites on Little Dome C, the maximum age of the ice is almost 1.5 Ma. We also highlight a new potential drill site called North Patch with ice up to 2 Ma. Finally, we explore the nature of a stagnant ice layer at the base of the ice sheet which has been independently observed and modelled but is not well understood.
Isobel Rowell, Carlos Martin, Robert Mulvaney, Helena Pryer, Dieter Tetzner, Emily Doyle, Hara Madhav Talasila, Jilu Li, and Eric Wolff
Clim. Past, 19, 1699–1714, https://doi.org/10.5194/cp-19-1699-2023, https://doi.org/10.5194/cp-19-1699-2023, 2023
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We present an age scale for a new type of ice core from a vulnerable region in West Antarctic, which is lacking in longer-term (greater than a few centuries) ice core records. The Sherman Island core extends to greater than 1 kyr. We provide modelling evidence for the potential of a 10 kyr long core. We show that this new type of ice core can be robustly dated and that climate records from this core will be a significant addition to existing regional climate records.
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
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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.
Hilary A. Dugan, Peter T. Doran, Denys Grombacher, Esben Auken, Thue Bording, Nikolaj Foged, Neil Foley, Jill Mikucki, Ross A. Virginia, and Slawek Tulaczyk
The Cryosphere, 16, 4977–4983, https://doi.org/10.5194/tc-16-4977-2022, https://doi.org/10.5194/tc-16-4977-2022, 2022
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In the McMurdo Dry Valleys of Antarctica, a deep groundwater system has been hypothesized to connect Don Juan Pond and Lake Vanda, both surface waterbodies that contain very high concentrations of salt. This is unusual, since permafrost in polar landscapes is thought to prevent subsurface hydrologic connectivity. We show results from an airborne geophysical survey that reveals widespread unfrozen brine in Wright Valley and points to the potential for deep valley-wide brine conduits.
Alexander O. Hager, Matthew J. Hoffman, Stephen F. Price, and Dustin M. Schroeder
The Cryosphere, 16, 3575–3599, https://doi.org/10.5194/tc-16-3575-2022, https://doi.org/10.5194/tc-16-3575-2022, 2022
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The presence of water beneath glaciers is a control on glacier speed and ocean-caused melting, yet it has been unclear whether sizable volumes of water can exist beneath Antarctic glaciers or how this water may flow along the glacier bed. We use computer simulations, supported by observations, to show that enough water exists at the base of Thwaites Glacier, Antarctica, to form "rivers" beneath the glacier. These rivers likely moderate glacier speed and may influence its rate of retreat.
M. Reza Ershadi, Reinhard Drews, Carlos Martín, Olaf Eisen, Catherine Ritz, Hugh Corr, Julia Christmann, Ole Zeising, Angelika Humbert, and Robert Mulvaney
The Cryosphere, 16, 1719–1739, https://doi.org/10.5194/tc-16-1719-2022, https://doi.org/10.5194/tc-16-1719-2022, 2022
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Radio waves transmitted through ice split up and inform us about the ice sheet interior and orientation of single ice crystals. This can be used to infer how ice flows and improve projections on how it will evolve in the future. Here we used an inverse approach and developed a new algorithm to infer ice properties from observed radar data. We applied this technique to the radar data obtained at two EPICA drilling sites, where ice cores were used to validate our results.
Julie Z. Miller, Riley Culberg, David G. Long, Christopher A. Shuman, Dustin M. Schroeder, and Mary J. Brodzik
The Cryosphere, 16, 103–125, https://doi.org/10.5194/tc-16-103-2022, https://doi.org/10.5194/tc-16-103-2022, 2022
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We use L-band brightness temperature imagery from NASA's Soil Moisture Active Passive (SMAP) satellite to map the extent of perennial firn aquifer and ice slab areas within the Greenland Ice Sheet. As Greenland's climate continues to warm and seasonal surface melting increases in extent, intensity, and duration, quantifying the possible rapid expansion of perennial firn aquifers and ice slab areas has significant implications for understanding the stability of the Greenland Ice Sheet.
Marie G. P. Cavitte, Duncan A. Young, Robert Mulvaney, Catherine Ritz, Jamin S. Greenbaum, Gregory Ng, Scott D. Kempf, Enrica Quartini, Gail R. Muldoon, John Paden, Massimo Frezzotti, Jason L. Roberts, Carly R. Tozer, Dustin M. Schroeder, and Donald D. Blankenship
Earth Syst. Sci. Data, 13, 4759–4777, https://doi.org/10.5194/essd-13-4759-2021, https://doi.org/10.5194/essd-13-4759-2021, 2021
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We present a data set consisting of ice-penetrating-radar internal stratigraphy: 26 internal reflecting horizons that cover the greater Dome C area, East Antarctica, the most extensive IRH data set to date in the region. This data set uses radar surveys collected over the span of 10 years, starting with an airborne international collaboration in 2008 to explore the region, up to the detailed ground-based surveys in support of the European Beyond EPICA – Oldest Ice (BE-OI) project.
Sarah U. Neuhaus, Slawek M. Tulaczyk, Nathan D. Stansell, Jason J. Coenen, Reed P. Scherer, Jill A. Mikucki, and Ross D. Powell
The Cryosphere, 15, 4655–4673, https://doi.org/10.5194/tc-15-4655-2021, https://doi.org/10.5194/tc-15-4655-2021, 2021
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We estimate the timing of post-LGM grounding line retreat and readvance in the Ross Sea sector of Antarctica. Our analyses indicate that the grounding line retreated over our field sites within the past 5000 years (coinciding with a warming climate) and readvanced roughly 1000 years ago (coinciding with a cooling climate). Based on these results, we propose that the Siple Coast grounding line motions in the middle to late Holocene were driven by relatively modest changes in regional climate.
Krista F. Myers, Peter T. Doran, Slawek M. Tulaczyk, Neil T. Foley, Thue S. Bording, Esben Auken, Hilary A. Dugan, Jill A. Mikucki, Nikolaj Foged, Denys Grombacher, and Ross A. Virginia
The Cryosphere, 15, 3577–3593, https://doi.org/10.5194/tc-15-3577-2021, https://doi.org/10.5194/tc-15-3577-2021, 2021
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Lake Fryxell, Antarctica, has undergone hundreds of meters of change in recent geologic history. However, there is disagreement on when lake levels were higher and by how much. This study uses resistivity data to map the subsurface conditions (frozen versus unfrozen ground) to map ancient shorelines. Our models indicate that Lake Fryxell was up to 60 m higher just 1500 to 4000 years ago. This amount of lake level change shows how sensitive these systems are to small changes in temperature.
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
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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.
Slawek M. Tulaczyk and Neil T. Foley
The Cryosphere, 14, 4495–4506, https://doi.org/10.5194/tc-14-4495-2020, https://doi.org/10.5194/tc-14-4495-2020, 2020
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Much of what we know about materials hidden beneath glaciers and ice sheets on Earth has been interpreted using radar reflection from the ice base. A common assumption is that electrical conductivity of the sub-ice materials does not influence the reflection strength and that the latter is controlled only by permittivity, which depends on the fraction of water in these materials. Here we argue that sub-ice electrical conductivity should be generally considered when interpreting radar records.
Iain Wheel, Poul Christoffersen, and Sebastian H. Mernild
The Cryosphere Discuss., https://doi.org/10.5194/tc-2020-194, https://doi.org/10.5194/tc-2020-194, 2020
Manuscript not accepted for further review
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Down-fjord winds, known as katabatic winds, are shown to increase water temperatures close to Helheim Glacier through circulation changes. More importantly, strong winds are shown to break up the sea-ice and iceberg matrix in front of the glacier which through a loss of support to the glacier leads to retreat of up to 1.5 km. Therefore katabatic winds are hypothesised to play an important role in the retreat of Helheim Glacier and to be important in the retreat of other Greenland glaciers.
Samuel J. Cook, Poul Christoffersen, Joe Todd, Donald Slater, and Nolwenn Chauché
The Cryosphere, 14, 905–924, https://doi.org/10.5194/tc-14-905-2020, https://doi.org/10.5194/tc-14-905-2020, 2020
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This paper models how water flows beneath a large Greenlandic glacier and how the structure of the drainage system it flows in changes over time. We also look at how this affects melting driven by freshwater plumes at the glacier front, as well as the implications for glacier flow and sea-level rise. We find an active drainage system and plumes exist year round, contradicting previous assumptions and suggesting more melting may not slow the glacier down, unlike at other sites in Greenland.
Michael A. Cooper, Thomas M. Jordan, Dustin M. Schroeder, Martin J. Siegert, Christopher N. Williams, and Jonathan L. Bamber
The Cryosphere, 13, 3093–3115, https://doi.org/10.5194/tc-13-3093-2019, https://doi.org/10.5194/tc-13-3093-2019, 2019
Sarah U. Neuhaus, Slawek M. Tulaczyk, and Carolyn Branecky Begeman
The Cryosphere, 13, 1785–1799, https://doi.org/10.5194/tc-13-1785-2019, https://doi.org/10.5194/tc-13-1785-2019, 2019
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Relatively few studies have been carried out on icebergs inside fjords, despite the fact that the majority of recent sea level rise has resulted from glaciers terminating in fjords. We examine the size and spatial distribution of icebergs in Columbia Fjord, Alaska, over a period of 8 months to determine their influence on fjord dynamics.
Joe Todd, Poul Christoffersen, Thomas Zwinger, Peter Råback, and Douglas I. Benn
The Cryosphere, 13, 1681–1694, https://doi.org/10.5194/tc-13-1681-2019, https://doi.org/10.5194/tc-13-1681-2019, 2019
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The Greenland Ice Sheet loses 30 %–60 % of its ice due to iceberg calving. Calving processes and their links to climate are not well understood or incorporated into numerical models of glaciers. Here we use a new 3-D calving model to investigate calving at Store Glacier, West Greenland, and test its sensitivity to increased submarine melting and reduced support from ice mélange (sea ice and icebergs). We find Store remains fairly stable despite these changes, but less so in the southern side.
Thomas R. Chudley, Poul Christoffersen, Samuel H. Doyle, Antonio Abellan, and Neal Snooke
The Cryosphere, 13, 955–968, https://doi.org/10.5194/tc-13-955-2019, https://doi.org/10.5194/tc-13-955-2019, 2019
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Unmanned Aerial Vehicles (UAVs) are increasingly common tools in the geosciences, but their use requires good ground control in order to make accurate georeferenced models. This is difficult in applications such as glaciology, where access to study sites can be hazardous. We show that a new technique utilising on-board GPS post-processing can match and even improve on ground-control-based methods, and, as a result, can produce accurate glacier velocity fields even on an inland ice sheet.
Brent C. Christner, Heather F. Lavender, Christina L. Davis, Erin E. Oliver, Sarah U. Neuhaus, Krista F. Myers, Birgit Hagedorn, Slawek M. Tulaczyk, Peter T. Doran, and William C. Stone
The Cryosphere, 12, 3653–3669, https://doi.org/10.5194/tc-12-3653-2018, https://doi.org/10.5194/tc-12-3653-2018, 2018
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Solar radiation that penetrates into the glacier heats the ice to produce nutrient-containing meltwater and provides light that fuels an ecosystem within the ice. Our analysis documents a near-surface photic zone in a glacier that functions as a liquid water oasis in the ice over half the annual cycle. Since microbial growth on glacier surfaces reduces the amount of solar radiation reflected, microbial processes at depths below the surface may also darken ice and accelerate meltwater production.
Thomas M. Jordan, Christopher N. Williams, Dustin M. Schroeder, Yasmina M. Martos, Michael A. Cooper, Martin J. Siegert, John D. Paden, Philippe Huybrechts, and Jonathan L. Bamber
The Cryosphere, 12, 2831–2854, https://doi.org/10.5194/tc-12-2831-2018, https://doi.org/10.5194/tc-12-2831-2018, 2018
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Here, via analysis of radio-echo sounding data, we place a new observational constraint upon the basal water distribution beneath the Greenland Ice Sheet. In addition to the outlet glaciers, we demonstrate widespread water storage in the northern and eastern ice-sheet interior, a notable feature being a "corridor" of basal water extending from NorthGRIP to Petermann Glacier. The basal water distribution and its relationship with basal temperature provides a new constraint for numerical models.
Thomas M. Jordan, Michael A. Cooper, Dustin M. Schroeder, Christopher N. Williams, John D. Paden, Martin J. Siegert, and Jonathan L. Bamber
The Cryosphere, 11, 1247–1264, https://doi.org/10.5194/tc-11-1247-2017, https://doi.org/10.5194/tc-11-1247-2017, 2017
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Using radio-echo sounding data from northern Greenland, we demonstrate that subglacial roughness exhibits self-affine (fractal) scaling behaviour. This enables us to assess topographic control upon the bed-echo waveform, and explain the spatial distribution of the degree of scattering (specular and diffuse reflections). Via comparison with a prediction for the basal thermal state (thawed and frozen regions of the bed) we discuss the consequences of our study for basal water discrimination.
Daniel Farinotti, Douglas J. Brinkerhoff, Garry K. C. Clarke, Johannes J. Fürst, Holger Frey, Prateek Gantayat, Fabien Gillet-Chaulet, Claire Girard, Matthias Huss, Paul W. Leclercq, Andreas Linsbauer, Horst Machguth, Carlos Martin, Fabien Maussion, Mathieu Morlighem, Cyrille Mosbeux, Ankur Pandit, Andrea Portmann, Antoine Rabatel, RAAJ Ramsankaran, Thomas J. Reerink, Olivier Sanchez, Peter A. Stentoft, Sangita Singh Kumari, Ward J. J. van Pelt, Brian Anderson, Toby Benham, Daniel Binder, Julian A. Dowdeswell, Andrea Fischer, Kay Helfricht, Stanislav Kutuzov, Ivan Lavrentiev, Robert McNabb, G. Hilmar Gudmundsson, Huilin Li, and Liss M. Andreassen
The Cryosphere, 11, 949–970, https://doi.org/10.5194/tc-11-949-2017, https://doi.org/10.5194/tc-11-949-2017, 2017
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ITMIX – the Ice Thickness Models Intercomparison eXperiment – was the first coordinated performance assessment for models inferring glacier ice thickness from surface characteristics. Considering 17 different models and 21 different test cases, we show that although solutions of individual models can differ considerably, an ensemble average can yield uncertainties in the order of 10 ± 24 % the mean ice thickness. Ways forward for improving such estimates are sketched.
A. Damsgaard, D. L. Egholm, J. A. Piotrowski, S. Tulaczyk, N. K. Larsen, and C. F. Brædstrup
The Cryosphere, 9, 2183–2200, https://doi.org/10.5194/tc-9-2183-2015, https://doi.org/10.5194/tc-9-2183-2015, 2015
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This paper details a new algorithm for performing computational experiments of subglacial granular deformation. The numerical approach allows detailed studies of internal sediment and pore-water dynamics under shear. Feedbacks between sediment grains and pore water can cause rate-dependent strengthening, which additionally contributes to the plastic shear strength of the granular material. Hardening can stabilise patches of the subglacial beds with implications for landform development.
C. Martín, R. Mulvaney, G. H. Gudmundsson, and H. Corr
Clim. Past, 11, 547–557, https://doi.org/10.5194/cp-11-547-2015, https://doi.org/10.5194/cp-11-547-2015, 2015
J. C. Ryan, A. L. Hubbard, J. E. Box, J. Todd, P. Christoffersen, J. R. Carr, T. O. Holt, and N. Snooke
The Cryosphere, 9, 1–11, https://doi.org/10.5194/tc-9-1-2015, https://doi.org/10.5194/tc-9-1-2015, 2015
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An unmanned aerial vehicle (UAV) equipped with a commercial digital camera enabled us to obtain high-resolution digital images of the calving front of Store glacier, Greenland. The three sorties flown enabled key glaciological parameters to be quantified in sufficient detail to reveal that the terminus of Store glacier is a complex system with large variations in crevasse patterns surface velocities, calving processes, surface elevations and front positions at a daily and seasonal timescale.
J. Todd and P. Christoffersen
The Cryosphere, 8, 2353–2365, https://doi.org/10.5194/tc-8-2353-2014, https://doi.org/10.5194/tc-8-2353-2014, 2014
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Many iceberg-calving glaciers in Greenland have recently been observed to accelerate and retreat, prompting fears about their future stability in the face of climate change. We present results from a flow modelling study of Store Glacier, West Greenland, which suggest that glacier geometry may play an important role in determining calving glacier stability. Store Glacier flows into a narrow, shallow fjord and our model suggests this may make it insensitive to future ocean warming.
B. Sun, J. C. Moore, T. Zwinger, L. Zhao, D. Steinhage, X. Tang, D. Zhang, X. Cui, and C. Martín
The Cryosphere, 8, 1121–1128, https://doi.org/10.5194/tc-8-1121-2014, https://doi.org/10.5194/tc-8-1121-2014, 2014
T. Zwinger, M. Schäfer, C. Martín, and J. C. Moore
The Cryosphere, 8, 607–621, https://doi.org/10.5194/tc-8-607-2014, https://doi.org/10.5194/tc-8-607-2014, 2014
O. Gagliardini, T. Zwinger, F. Gillet-Chaulet, G. Durand, L. Favier, B. de Fleurian, R. Greve, M. Malinen, C. Martín, P. Råback, J. Ruokolainen, M. Sacchettini, M. Schäfer, H. Seddik, and J. Thies
Geosci. Model Dev., 6, 1299–1318, https://doi.org/10.5194/gmd-6-1299-2013, https://doi.org/10.5194/gmd-6-1299-2013, 2013
J. De Rydt, G. H. Gudmundsson, H. F. J. Corr, and P. Christoffersen
The Cryosphere, 7, 407–417, https://doi.org/10.5194/tc-7-407-2013, https://doi.org/10.5194/tc-7-407-2013, 2013
M. O'Leary and P. Christoffersen
The Cryosphere, 7, 119–128, https://doi.org/10.5194/tc-7-119-2013, https://doi.org/10.5194/tc-7-119-2013, 2013
Related subject area
Discipline: Ice sheets | Subject: Field Studies
Brief communication: Reduced bandwidth improves the depth limit of the radar coherence method for detecting ice crystal fabric asymmetry
Ice plate deformation and cracking revealed by an in situ-distributed acoustic sensing array
A field study on ice melting and breakup in a boreal lake, Pääjärvi, in Finland
Downhole distributed acoustic seismic profiling at Skytrain Ice Rise, West Antarctica
Glacier algae accelerate melt rates on the south-western Greenland Ice Sheet
Pore morphology of polar firn around closure revealed by X-ray tomography
Ole Zeising, Álvaro Arenas-Pingarrón, Alex M. Brisbourne, and Carlos Martín
EGUsphere, https://doi.org/10.5194/egusphere-2024-2519, https://doi.org/10.5194/egusphere-2024-2519, 2024
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Ice crystal orientation influence how glacier ice deforms. Radar polarimetry is commonly used to study the bulk ice crystal orientation, but the often used coherence method only provides information of the shallow ice in fast-flowing areas. This study shows that reducing the bandwidth of high-bandwidth radar data significantly enhances the depth limit of the coherence method. This improvement helps us to better understand ice dynamics in fast-flowing ice streams.
Jun Xie, Xiangfang Zeng, Chao Liang, Sidao Ni, Risheng Chu, Feng Bao, Rongbing Lin, Benxin Chi, and Hao Lv
The Cryosphere, 18, 837–847, https://doi.org/10.5194/tc-18-837-2024, https://doi.org/10.5194/tc-18-837-2024, 2024
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Seismology can help study the mechanism of disintegration of floating ice plates. We conduct a seismic experiment on a frozen lake using a distributed acoustic sensing array. Icequakes and low-frequency events are detected with an artificial intelligence method. Our study demonstrates the merit of distributed acoustic sensing array in illuminating the internal failure process and properties of the ice shelf, which eventually contributes to the understanding and prediction of ice shelf collapse.
Yaodan Zhang, Marta Fregona, John Loehr, Joonatan Ala-Könni, Shuang Song, Matti Leppäranta, and Zhijun Li
The Cryosphere, 17, 2045–2058, https://doi.org/10.5194/tc-17-2045-2023, https://doi.org/10.5194/tc-17-2045-2023, 2023
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There are few detailed studies during the ice decay period, primarily because in situ observations during decay stages face enormous challenges due to safety issues. In the present work, ice monitoring was based on foot, hydrocopter, and boat to get a full time series of the evolution of ice structure and geochemical properties. We argue that the rapid changes in physical and geochemical properties of ice have an important influence on regional climate and the ecological environment under ice.
Alex M. Brisbourne, Michael Kendall, Sofia-Katerina Kufner, Thomas S. Hudson, and Andrew M. Smith
The Cryosphere, 15, 3443–3458, https://doi.org/10.5194/tc-15-3443-2021, https://doi.org/10.5194/tc-15-3443-2021, 2021
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How ice sheets flowed in the past is written into the structure and texture of the ice sheet itself. Measuring this structure and properties of the ice can help us understand the recent behaviour of the ice sheets. We use a relatively new technique, not previously attempted in Antarctica, to measure the seismic vibrations of a fibre optic cable down a borehole. We demonstrate the potential of this technique to unravel past ice flow and see hints of these complex signals from the ice flow itself.
Joseph M. Cook, Andrew J. Tedstone, Christopher Williamson, Jenine McCutcheon, Andrew J. Hodson, Archana Dayal, McKenzie Skiles, Stefan Hofer, Robert Bryant, Owen McAree, Andrew McGonigle, Jonathan Ryan, Alexandre M. Anesio, Tristram D. L. Irvine-Fynn, Alun Hubbard, Edward Hanna, Mark Flanner, Sathish Mayanna, Liane G. Benning, Dirk van As, Marian Yallop, James B. McQuaid, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 309–330, https://doi.org/10.5194/tc-14-309-2020, https://doi.org/10.5194/tc-14-309-2020, 2020
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Melting of the Greenland Ice Sheet (GrIS) is a major source of uncertainty for sea level rise projections. Ice-darkening due to the growth of algae has been recognized as a potential accelerator of melting. This paper measures and models the algae-driven ice melting and maps the algae over the ice sheet for the first time. We estimate that as much as 13 % total runoff from the south-western GrIS can be attributed to these algae, showing that they must be included in future mass balance models.
Alexis Burr, Clément Ballot, Pierre Lhuissier, Patricia Martinerie, Christophe L. Martin, and Armelle Philip
The Cryosphere, 12, 2481–2500, https://doi.org/10.5194/tc-12-2481-2018, https://doi.org/10.5194/tc-12-2481-2018, 2018
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Three-dimensional imaging of the pore network of polar firn from Antarctica was realized in order to relate the morphological evolution of pores with their progressive closure with depth. Evaluating the closed porosity was found to be very dependent on the size of samples and image reconstructions. A connectivity index, which is a parameter less dependent on such issues, was proposed and proved to accurately predict the close-off depths and densities of two polar sites.
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Short summary
If the molecules that make up ice are oriented in specific ways, the ice becomes softer and enhances flow. We use radar to measure the orientation of ice molecules in the top 1400 m of the Western Antarctic Ice Sheet Divide. Our results match those from an ice core extracted 10 years ago and conclude that the ice flow has not changed direction for the last 6700 years. Our methods are straightforward and accurate and can be applied in places across ice sheets unsuitable for ice coring.
If the molecules that make up ice are oriented in specific ways, the ice becomes softer and...
