Articles | Volume 18, issue 8
https://doi.org/10.5194/tc-18-3699-2024
© Author(s) 2024. 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-18-3699-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Misidentified subglacial lake beneath the Devon Ice Cap, Canadian Arctic: a new interpretation from seismic and electromagnetic data
Siobhan F. Killingbeck
CORRESPONDING AUTHOR
Department of Earth and Atmospheric Sciences, Faculty of Science, University of Alberta, Edmonton, Canada
Department of Geography and Environmental Management, Faculty of Environment, University of Waterloo, Waterloo, Canada
Anja Rutishauser
Geological Survey of Denmark and Greenland, Copenhagen, Denmark
Martyn J. Unsworth
Department of Physics, Faculty of Science, University of Alberta, Edmonton, Canada
Ashley Dubnick
YukonU Research Centre, Yukon University, 520 College Drive, Whitehorse, YT, Y1A 5N5, Canada
Alison S. Criscitiello
Department of Earth and Atmospheric Sciences, Faculty of Science, University of Alberta, Edmonton, Canada
James Killingbeck
independent researcher
Christine F. Dow
Department of Geography and Environmental Management, Faculty of Environment, University of Waterloo, Waterloo, Canada
Tim Hill
Department of Earth Sciences, Simon Fraser University, Burnaby, Canada
Adam D. Booth
School of Earth and Environment, University of Leeds, Leeds, UK
Brittany Main
Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, ON, Canada
Eric Brossier
independent researcher
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Siobhan F. Killingbeck, Adam D. Booth, Philip W. Livermore, C. Richard Bates, and Landis J. West
Solid Earth, 11, 75–94, https://doi.org/10.5194/se-11-75-2020, https://doi.org/10.5194/se-11-75-2020, 2020
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This paper presents MuLTI-TEM, a Bayesian inversion tool for inverting TEM data with independent depth constraints to provide statistical properties and uncertainty analysis of the resistivity profile with depth. MuLTI-TEM is highly versatile, being compatible with most TEM survey designs, ground-based or airborne, along with the depth constraints being provided from any external source. Here, we present an application of MuLTI-TEM to characterise the subglacial water under a Norwegian glacier.
Adam J. Hepburn, Christine F. Dow, Antti Ojala, Joni Mäkinen, Elina Ahokangas, Jussi Hovikoski, Jukka-Pekka Palmu, and Kari Kajuutti
The Cryosphere, 18, 4873–4916, https://doi.org/10.5194/tc-18-4873-2024, https://doi.org/10.5194/tc-18-4873-2024, 2024
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Terrain formerly occupied by ice sheets in the last ice age allows us to parameterize models of basal water flow using terrain and data unavailable beneath current ice sheets. Using GlaDS, a 2D basal hydrology model, we explore the origin of murtoos, a specific landform found throughout Finland that is thought to mark the upper limit of channels beneath the ice. Our results validate many of the predictions of murtoo origins and demonstrate that such models can be used to explore past ice sheets.
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.
Kirk M. Scanlan, Anja Rutishauser, and Sebastian B. Simonsen
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In this paper we investigate how to interpret Greenland surface roughness derived from reflected radar altimetry signals. Based on a comparison to conventional laser altimetry results, we 1) define a new mapping between the radar surface echo power strengths and surface roughness and 2) contextualize the horizontal lengths over which this roughness is representative. This work provides critical insight into how these observations integrate into Greenland Ice Sheet mass balance modeling.
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Earth Syst. Sci. Data, 16, 4103–4118, https://doi.org/10.5194/essd-16-4103-2024, https://doi.org/10.5194/essd-16-4103-2024, 2024
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The Greenland Ecosystem Monitoring programme has been running since 1995. In 2008, the Glaciological monitoring sub-program GlacioBasis was initiated at the Zackenberg site in northeast Greenland, with a transect of three weather stations on the A. P. Olsen Ice Cap. In 2022, the weather stations were replaced with a more standardized set up. Here, we provide the reprocessed and quality-checked data from 2008 to 2022, i.e., the first 15 years of continued monitoring.
Xin Yang, Kimberly Strong, Alison S. Criscitiello, Marta Santos-Garcia, Kristof Bognar, Xiaoyi Zhao, Pierre Fogal, Kaley A. Walker, Sara M. Morris, and Peter Effertz
Atmos. Chem. Phys., 24, 5863–5886, https://doi.org/10.5194/acp-24-5863-2024, https://doi.org/10.5194/acp-24-5863-2024, 2024
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This study uses snow samples collected from a Canadian high Arctic site, Eureka, to demonstrate that surface snow in early spring is a net sink of atmospheric bromine and nitrogen. Surface snow bromide and nitrate are significantly correlated, indicating the oxidation of reactive nitrogen is accelerated by reactive bromine. In addition, we show evidence that snow photochemical release of reactive bromine is very weak, and its emission flux is much smaller than the deposition flux of bromide.
Anja Rutishauser, Kirk M. Scanlan, Baptiste Vandecrux, Nanna B. Karlsson, Nicolas Jullien, Andreas P. Ahlstrøm, Robert S. Fausto, and Penelope How
The Cryosphere, 18, 2455–2472, https://doi.org/10.5194/tc-18-2455-2024, https://doi.org/10.5194/tc-18-2455-2024, 2024
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The Greenland Ice Sheet interior is covered by a layer of firn, which is important for surface meltwater runoff and contributions to global sea-level rise. Here, we combine airborne radar sounding and laser altimetry measurements to delineate vertically homogeneous and heterogeneous firn. Our results reveal changes in firn between 2011–2019, aligning well with known climatic events. This approach can be used to outline firn areas primed for significantly changing future meltwater runoff.
Tessa R. Vance, Nerilie J. Abram, Alison S. Criscitiello, Camilla K. Crockart, Aylin DeCampo, Vincent Favier, Vasileios Gkinis, Margaret Harlan, Sarah L. Jackson, Helle A. Kjær, Chelsea A. Long, Meredith K. Nation, Christopher T. Plummer, Delia Segato, Andrea Spolaor, and Paul T. Vallelonga
Clim. Past, 20, 969–990, https://doi.org/10.5194/cp-20-969-2024, https://doi.org/10.5194/cp-20-969-2024, 2024
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This study presents the chronologies from the new Mount Brown South ice cores from East Antarctica, which were developed by counting annual layers in the ice core data and aligning these to volcanic sulfate signatures. The uncertainty in the dating is quantified, and we discuss initial results from seasonal cycle analysis and mean annual concentrations. The chronologies will underpin the development of new proxy records for East Antarctica spanning the past millennium.
Christine F. Dow, Derek Mueller, Peter Wray, Drew Friedrichs, Alexander L. Forrest, Jasmin B. McInerney, Jamin Greenbaum, Donald D. Blankenship, Choon Ki Lee, and Won Sang Lee
The Cryosphere, 18, 1105–1123, https://doi.org/10.5194/tc-18-1105-2024, https://doi.org/10.5194/tc-18-1105-2024, 2024
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Ice shelves are a key control on Antarctic contribution to sea level rise. We examine the Nansen Ice Shelf in East Antarctica using a combination of field-based and satellite data. We find the basal topography of the ice shelf is highly variable, only partially visible in satellite datasets. We also find that the thinnest region of the ice shelf is altered over time by ice flow rates and ocean melting. These processes can cause fractures to form that eventually result in large calving events.
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.
Baptiste Vandecrux, Jason E. Box, Andreas P. Ahlstrøm, Signe B. Andersen, Nicolas Bayou, William T. Colgan, Nicolas J. Cullen, Robert S. Fausto, Dominik Haas-Artho, Achim Heilig, Derek A. Houtz, Penelope How, Ionut Iosifescu Enescu, Nanna B. Karlsson, Rebecca Kurup Buchholz, Kenneth D. Mankoff, Daniel McGrath, Noah P. Molotch, Bianca Perren, Maiken K. Revheim, Anja Rutishauser, Kevin Sampson, Martin Schneebeli, Sandy Starkweather, Simon Steffen, Jeff Weber, Patrick J. Wright, Henry Jay Zwally, and Konrad Steffen
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The Greenland Climate Network (GC-Net) comprises stations that have been monitoring the weather on the Greenland Ice Sheet for over 30 years. These stations are being replaced by newer ones maintained by the Geological Survey of Denmark and Greenland (GEUS). The historical data were reprocessed to improve their quality, and key information about the weather stations has been compiled. This augmented dataset is available at https://doi.org/10.22008/FK2/VVXGUT (Steffen et al., 2022).
Koi McArthur, Felicity S. McCormack, and Christine F. Dow
The Cryosphere, 17, 4705–4727, https://doi.org/10.5194/tc-17-4705-2023, https://doi.org/10.5194/tc-17-4705-2023, 2023
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Using subglacial hydrology model outputs for Denman Glacier, East Antarctica, we investigated the effects of various friction laws and effective pressure inputs on ice dynamics modeling over the same glacier. The Schoof friction law outperformed the Budd friction law, and effective pressure outputs from the hydrology model outperformed a typically prescribed effective pressure. We propose an empirical prescription of effective pressure to be used in the absence of hydrology model outputs.
Felicity S. McCormack, Jason L. Roberts, Bernd Kulessa, Alan Aitken, Christine F. Dow, Lawrence Bird, Benjamin K. Galton-Fenzi, Katharina Hochmuth, Richard S. Jones, Andrew N. Mackintosh, and Koi McArthur
The Cryosphere, 17, 4549–4569, https://doi.org/10.5194/tc-17-4549-2023, https://doi.org/10.5194/tc-17-4549-2023, 2023
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Changes in Antarctic surface elevation can cause changes in ice and basal water flow, impacting how much ice enters the ocean. We find that ice and basal water flow could divert from the Totten to the Vanderford Glacier, East Antarctica, under only small changes in the surface elevation, with implications for estimates of ice loss from this region. Further studies are needed to determine when this could occur and if similar diversions could occur elsewhere in Antarctica due to climate change.
Whyjay Zheng, Shashank Bhushan, Maximillian Van Wyk De Vries, William Kochtitzky, David Shean, Luke Copland, Christine Dow, Renette Jones-Ivey, and Fernando Pérez
The Cryosphere, 17, 4063–4078, https://doi.org/10.5194/tc-17-4063-2023, https://doi.org/10.5194/tc-17-4063-2023, 2023
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We design and propose a method that can evaluate the quality of glacier velocity maps. The method includes two numbers that we can calculate for each velocity map. Based on statistics and ice flow physics, velocity maps with numbers close to the recommended values are considered to have good quality. We test the method using the data from Kaskawulsh Glacier, Canada, and release an open-sourced software tool called GLAcier Feature Tracking testkit (GLAFT) to help users assess their velocity maps.
Tim Hill and Christine F. Dow
The Cryosphere, 17, 2607–2624, https://doi.org/10.5194/tc-17-2607-2023, https://doi.org/10.5194/tc-17-2607-2023, 2023
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Water flow across the surface of the Greenland Ice Sheet controls the rate of water flow to the glacier bed. Here, we simulate surface water flow for a small catchment on the southwestern Greenland Ice Sheet. Our simulations predict significant differences in the form of surface water flow in high and low melt years depending on the rate and intensity of surface melt. These model outputs will be important in future work assessing the impact of surface water flow on subglacial water pressure.
Kristian Chan, Cyril Grima, Anja Rutishauser, Duncan A. Young, Riley Culberg, and Donald D. Blankenship
The Cryosphere, 17, 1839–1852, https://doi.org/10.5194/tc-17-1839-2023, https://doi.org/10.5194/tc-17-1839-2023, 2023
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Climate warming has led to more surface meltwater produced on glaciers that can refreeze in firn to form ice layers. Our work evaluates the use of dual-frequency ice-penetrating radar to characterize these ice layers on the Devon Ice Cap. Results indicate that they are meters thick and widespread, and thus capable of supporting lateral meltwater runoff from the top of ice layers. We find that some of this meltwater runoff could be routed through supraglacial rivers in the ablation zone.
Xin Yang, Kimberly Strong, Alison S. Criscitiello, Marta Santos-Garcia, Kristof Bognar, Xiaoyi Zhao, Pierre Fogal, Kaley A. Walker, Sara M. Morris, and Peter Effertz
EGUsphere, https://doi.org/10.5194/egusphere-2022-696, https://doi.org/10.5194/egusphere-2022-696, 2022
Preprint archived
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Snow pack in high Arctic plays a key role in polar atmospheric chemistry, especially in spring when photochemistry becomes active. By sampling surface snow from a Canadian high Arctic location at Eureka, Nunavut (80° N, 86° W), we demonstrate that surface snow is a net sink rather than a source of atmospheric reactive bromine and nitrate. This finding is new and opposite to previous conclusions that snowpack is a large and direct source of reactive bromine in polar spring.
Anja Rutishauser, Donald D. Blankenship, Duncan A. Young, Natalie S. Wolfenbarger, Lucas H. Beem, Mark L. Skidmore, Ashley Dubnick, and Alison S. Criscitiello
The Cryosphere, 16, 379–395, https://doi.org/10.5194/tc-16-379-2022, https://doi.org/10.5194/tc-16-379-2022, 2022
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Recently, a hypersaline subglacial lake complex was hypothesized to lie beneath Devon Ice Cap, Canadian Arctic. Here, we present results from a follow-on targeted aerogeophysical survey. Our results support the evidence for a hypersaline subglacial lake and reveal an extensive brine network, suggesting more complex subglacial hydrological conditions than previously inferred. This hypersaline system may host microbial habitats, making it a compelling analog for bines on other icy worlds.
Camilla K. Crockart, Tessa R. Vance, Alexander D. Fraser, Nerilie J. Abram, Alison S. Criscitiello, Mark A. J. Curran, Vincent Favier, Ailie J. E. Gallant, Christoph Kittel, Helle A. Kjær, Andrew R. Klekociuk, Lenneke M. Jong, Andrew D. Moy, Christopher T. Plummer, Paul T. Vallelonga, Jonathan Wille, and Lingwei Zhang
Clim. Past, 17, 1795–1818, https://doi.org/10.5194/cp-17-1795-2021, https://doi.org/10.5194/cp-17-1795-2021, 2021
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We present preliminary analyses of the annual sea salt concentrations and snowfall accumulation in a new East Antarctic ice core, Mount Brown South. We compare this record with an updated Law Dome (Dome Summit South site) ice core record over the period 1975–2016. The Mount Brown South record preserves a stronger and inverse signal for the El Niño–Southern Oscillation (in austral winter and spring) compared to the Law Dome record (in summer).
Trude Eidhammer, Adam Booth, Sven Decker, Lu Li, Michael Barlage, David Gochis, Roy Rasmussen, Kjetil Melvold, Atle Nesje, and Stefan Sobolowski
Hydrol. Earth Syst. Sci., 25, 4275–4297, https://doi.org/10.5194/hess-25-4275-2021, https://doi.org/10.5194/hess-25-4275-2021, 2021
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We coupled a detailed snow–ice model (Crocus) to represent glaciers in the Weather Research and Forecasting (WRF)-Hydro model and tested it on a well-studied glacier. Several observational systems were used to evaluate the system, i.e., satellites, ground-penetrating radar (used over the glacier for snow depth) and stake observations for glacier mass balance and discharge measurements in rivers from the glacier. Results showed improvements in the streamflow projections when including the model.
Naomi E. Ochwat, Shawn J. Marshall, Brian J. Moorman, Alison S. Criscitiello, and Luke Copland
The Cryosphere, 15, 2021–2040, https://doi.org/10.5194/tc-15-2021-2021, https://doi.org/10.5194/tc-15-2021-2021, 2021
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In May 2018 we drilled into Kaskawulsh Glacier to study how it is being affected by climate warming and used models to investigate the evolution of the firn since the 1960s. We found that the accumulation zone has experienced increased melting that has refrozen as ice layers and has formed a perennial firn aquifer. These results better inform climate-induced changes on northern glaciers and variables to take into account when estimating glacier mass change using remote-sensing methods.
Wei Wei, Donald D. Blankenship, Jamin S. Greenbaum, Noel Gourmelen, Christine F. Dow, Thomas G. Richter, Chad A. Greene, Duncan A. Young, SangHoon Lee, Tae-Wan Kim, Won Sang Lee, and Karen M. Assmann
The Cryosphere, 14, 1399–1408, https://doi.org/10.5194/tc-14-1399-2020, https://doi.org/10.5194/tc-14-1399-2020, 2020
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Getz Ice Shelf is the largest meltwater source from Antarctica of the Southern Ocean. This study compares the relative importance of the meltwater production of Getz from both ocean and subglacial sources. We show that basal melt rates are elevated where bathymetric troughs provide pathways for warm Circumpolar Deep Water to enter the Getz Ice Shelf cavity. In particular, we find that subshelf melting is enhanced where subglacially discharged fresh water flows across the grounding line.
Alex Brisbourne, Bernd Kulessa, Thomas Hudson, Lianne Harrison, Paul Holland, Adrian Luckman, Suzanne Bevan, David Ashmore, Bryn Hubbard, Emma Pearce, James White, Adam Booth, Keith Nicholls, and Andrew Smith
Earth Syst. Sci. Data, 12, 887–896, https://doi.org/10.5194/essd-12-887-2020, https://doi.org/10.5194/essd-12-887-2020, 2020
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Melting of the Larsen C Ice Shelf in Antarctica may lead to its collapse. To help estimate its lifespan we need to understand how the ocean can circulate beneath. This requires knowledge of the geometry of the sub-shelf cavity. New and existing measurements of seabed depth are integrated to produce a map of the ocean cavity beneath the ice shelf. The observed deep seabed may provide a pathway for circulation of warm ocean water but at the same time reduce rapid tidal melt at a critical location.
Ashley Dubnick, Martin Sharp, Brad Danielson, Alireza Saidi-Mehrabad, and Joel Barker
Biogeosciences, 17, 963–977, https://doi.org/10.5194/bg-17-963-2020, https://doi.org/10.5194/bg-17-963-2020, 2020
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We found that glaciers with basal temperatures near the melting point mobilize more solutes, nutrients, and microbes from the underlying substrate and are more likely to promote in situ biogeochemical activity than glaciers with basal temperatures well below the melting point. The temperature at the base of glaciers is therefore an important control on the biogeochemistry of ice near glacier beds, and, ultimately, the potential solutes, nutrients, and microbes exported from glaciated watersheds.
Philippe Massicotte, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Mathieu Ardyna, Laurent Arnaud, Lise Artigue, Cyril Aubry, Pierre Ayotte, Guislain Bécu, Simon Bélanger, Ronald Benner, Henry C. Bittig, Annick Bricaud, Éric Brossier, Flavienne Bruyant, Laurent Chauvaud, Debra Christiansen-Stowe, Hervé Claustre, Véronique Cornet-Barthaux, Pierre Coupel, Christine Cox, Aurelie Delaforge, Thibaud Dezutter, Céline Dimier, Florent Domine, Francis Dufour, Christiane Dufresne, Dany Dumont, Jens Ehn, Brent Else, Joannie Ferland, Marie-Hélène Forget, Louis Fortier, Martí Galí, Virginie Galindo, Morgane Gallinari, Nicole Garcia, Catherine Gérikas Ribeiro, Margaux Gourdal, Priscilla Gourvil, Clemence Goyens, Pierre-Luc Grondin, Pascal Guillot, Caroline Guilmette, Marie-Noëlle Houssais, Fabien Joux, Léo Lacour, Thomas Lacour, Augustin Lafond, José Lagunas, Catherine Lalande, Julien Laliberté, Simon Lambert-Girard, Jade Larivière, Johann Lavaud, Anita LeBaron, Karine Leblanc, Florence Le Gall, Justine Legras, Mélanie Lemire, Maurice Levasseur, Edouard Leymarie, Aude Leynaert, Adriana Lopes dos Santos, Antonio Lourenço, David Mah, Claudie Marec, Dominique Marie, Nicolas Martin, Constance Marty, Sabine Marty, Guillaume Massé, Atsushi Matsuoka, Lisa Matthes, Brivaela Moriceau, Pierre-Emmanuel Muller, Christopher-John Mundy, Griet Neukermans, Laurent Oziel, Christos Panagiotopoulos, Jean-Jacques Pangrazi, Ghislain Picard, Marc Picheral, France Pinczon du Sel, Nicole Pogorzelec, Ian Probert, Bernard Quéguiner, Patrick Raimbault, Joséphine Ras, Eric Rehm, Erin Reimer, Jean-François Rontani, Søren Rysgaard, Blanche Saint-Béat, Makoto Sampei, Julie Sansoulet, Catherine Schmechtig, Sabine Schmidt, Richard Sempéré, Caroline Sévigny, Yuan Shen, Margot Tragin, Jean-Éric Tremblay, Daniel Vaulot, Gauthier Verin, Frédéric Vivier, Anda Vladoiu, Jeremy Whitehead, and Marcel Babin
Earth Syst. Sci. Data, 12, 151–176, https://doi.org/10.5194/essd-12-151-2020, https://doi.org/10.5194/essd-12-151-2020, 2020
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The Green Edge initiative was developed to understand the processes controlling the primary productivity and the fate of organic matter produced during the Arctic spring bloom (PSB). In this article, we present an overview of an extensive and comprehensive dataset acquired during two expeditions conducted in 2015 and 2016 on landfast ice southeast of Qikiqtarjuaq Island in Baffin Bay.
Siobhan F. Killingbeck, Adam D. Booth, Philip W. Livermore, C. Richard Bates, and Landis J. West
Solid Earth, 11, 75–94, https://doi.org/10.5194/se-11-75-2020, https://doi.org/10.5194/se-11-75-2020, 2020
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This paper presents MuLTI-TEM, a Bayesian inversion tool for inverting TEM data with independent depth constraints to provide statistical properties and uncertainty analysis of the resistivity profile with depth. MuLTI-TEM is highly versatile, being compatible with most TEM survey designs, ground-based or airborne, along with the depth constraints being provided from any external source. Here, we present an application of MuLTI-TEM to characterise the subglacial water under a Norwegian glacier.
William Kochtitzky, Dominic Winski, Erin McConnel, Karl Kreutz, Seth Campbell, Ellyn M. Enderlin, Luke Copland, Scott Williamson, Brittany Main, Christine Dow, and Hester Jiskoot
The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-72, https://doi.org/10.5194/tc-2019-72, 2019
Manuscript not accepted for further review
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Donjek Glacier has experienced eight instability events since 1935. Here we use a suite of weather and satellite data to understand the impacts of climate on instability events. We find that while there has been a consistent amount of snow fall between instability events, the relationship between the two is unclear as they are both very consistent on decade timescales. We show that we need further glacier observations to understand why these glaciers become unstable.
Benedict T. I. Reinardy, Adam D. Booth, Anna L. C. Hughes, Clare M. Boston, Henning Åkesson, Jostein Bakke, Atle Nesje, Rianne H. Giesen, and Danni M. Pearce
The Cryosphere, 13, 827–843, https://doi.org/10.5194/tc-13-827-2019, https://doi.org/10.5194/tc-13-827-2019, 2019
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Cold-ice processes may be widespread within temperate glacier systems but the role of cold-ice processes in temperate glacier systems is relatively unknown. Climate forcing is the main control on glacier mass balance but potential for heterogeneous thermal conditions at temperate glaciers calls for improved model assessments of future evolution of thermal conditions and impacts on glacier dynamics and mass balance. Cold-ice processes need to be included in temperate glacier land system models.
Heidi M. Pickard, Alison S. Criscitiello, Christine Spencer, Martin J. Sharp, Derek C. G. Muir, Amila O. De Silva, and Cora J. Young
Atmos. Chem. Phys., 18, 5045–5058, https://doi.org/10.5194/acp-18-5045-2018, https://doi.org/10.5194/acp-18-5045-2018, 2018
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Perfluoroalkyl acids (PFAAs) are persistent, bioaccumulative compounds found in the environment far from source regions, including the remote Arctic. We collected a 15 m ice core from the Canadian High Arctic to measure a 38-year deposition record of PFAAs, proving information about major pollutant sources and production changes over time. Our results demonstrate that PFAAs have continuous and increasing deposition, despite recent North American regulations and phase-outs.
Suzanne L. Bevan, Adrian Luckman, Bryn Hubbard, Bernd Kulessa, David Ashmore, Peter Kuipers Munneke, Martin O'Leary, Adam Booth, Heidi Sevestre, and Daniel McGrath
The Cryosphere, 11, 2743–2753, https://doi.org/10.5194/tc-11-2743-2017, https://doi.org/10.5194/tc-11-2743-2017, 2017
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Five 90 m boreholes drilled into an Antarctic Peninsula ice shelf show units of ice that are denser than expected and must have formed from refrozen surface melt which has been buried and transported downstream. We used surface flow speeds and snow accumulation rates to work out where and when these units formed. Results show that, as well as recent surface melt, a period of strong melt occurred during the 18th century. Surface melt is thought to be a factor in causing recent ice-shelf break-up.
Peter Kuipers Munneke, Daniel McGrath, Brooke Medley, Adrian Luckman, Suzanne Bevan, Bernd Kulessa, Daniela Jansen, Adam Booth, Paul Smeets, Bryn Hubbard, David Ashmore, Michiel Van den Broeke, Heidi Sevestre, Konrad Steffen, Andrew Shepherd, and Noel Gourmelen
The Cryosphere, 11, 2411–2426, https://doi.org/10.5194/tc-11-2411-2017, https://doi.org/10.5194/tc-11-2411-2017, 2017
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How much snow falls on the Larsen C ice shelf? This is a relevant question, because this ice shelf might collapse sometime this century. To know if and when this could happen, we found out how much snow falls on its surface. This was difficult, because there are only very few measurements. Here, we used data from automatic weather stations, sled-pulled radars, and a climate model to find that melting the annual snowfall produces about 20 cm of water in the NE and over 70 cm in the SW.
David M. Miles, Ian R. Mann, Andy Kale, David K. Milling, Barry B. Narod, John R. Bennest, David Barona, and Martyn J. Unsworth
Geosci. Instrum. Method. Data Syst., 6, 377–396, https://doi.org/10.5194/gi-6-377-2017, https://doi.org/10.5194/gi-6-377-2017, 2017
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Fluxgate magnetometers are an important geophysical tool but are typically sensitive to changes in sensor temperature. We used a novel, low-cost calibration procedure to compare six matched sensors in which the material used as the mechanical support is varied and found that 30 % glass-filled PEEK engineering plastic is a good candidate for sensors. It is more economical, easier to machine, lighter, and more robust than historically used machinable ceramic.
Christine F. Dow, Mauro A. Werder, Sophie Nowicki, and Ryan T. Walker
The Cryosphere, 10, 1381–1393, https://doi.org/10.5194/tc-10-1381-2016, https://doi.org/10.5194/tc-10-1381-2016, 2016
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We examine the development and drainage of subglacial lakes in the Antarctic using a finite element hydrology model. Model outputs show development of slow-moving pressure waves initiated from water funneled from a large catchment into the ice stream. Lake drainage occurs due to downstream channel formation and changing system hydraulic gradients. These model outputs have implications for understanding controls on ice stream dynamics.
B. Medley, I. Joughin, B. E. Smith, S. B. Das, E. J. Steig, H. Conway, S. Gogineni, C. Lewis, A. S. Criscitiello, J. R. McConnell, M. R. van den Broeke, J. T. M. Lenaerts, D. H. Bromwich, J. P. Nicolas, and C. Leuschen
The Cryosphere, 8, 1375–1392, https://doi.org/10.5194/tc-8-1375-2014, https://doi.org/10.5194/tc-8-1375-2014, 2014
Related subject area
Discipline: Other | Subject: Subglacial Processes
Subglacial carbonate deposits as a potential proxy for a glacier's former presence
Matej Lipar, Andrea Martín-Pérez, Jure Tičar, Miha Pavšek, Matej Gabrovec, Mauro Hrvatin, Blaž Komac, Matija Zorn, Nadja Zupan Hajna, Jian-Xin Zhao, Russell N. Drysdale, and Mateja Ferk
The Cryosphere, 15, 17–30, https://doi.org/10.5194/tc-15-17-2021, https://doi.org/10.5194/tc-15-17-2021, 2021
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The U–Th ages of subglacial carbonate deposits from a recently exposed surface previously occupied by the disappearing glacier in the SE European Alps suggest the glacier’s presence throughout the entire Holocene. These thin deposits, formed by regelation, would have been easily eroded if exposed during previous Holocene climatic optima. The age data indicate the glacier’s present unprecedented level of retreat and the potential of subglacial carbonates to act as palaeoclimate proxies.
Cited articles
Booth, A. D., Clark, R. A., Kulessa, B., Murray, T., Carter, J., Doyle, S., and Hubbard, A.: Thin-layer effects in glaciological seismic amplitude-versus-angle (AVA) analysis: implications for characterising a subglacial till unit, Russell Glacier, West Greenland, The Cryosphere, 6, 909–922, https://doi.org/10.5194/tc-6-909-2012, 2012.
Bowling, J. S., Livingstone, S. J., Sole, A. J., and Chu, W.: Distribution and dynamics of Greenland subglacial lakes, Nat. Commun., 10, 2810, https://doi.org/10.1038/s41467-019-10821-w, 2019.
Brown, W. S.: Physical properties of seawater. Springer handbook of ocean engineering, 101–110, https://doi.org/10.1007/978-3-319-16649-0_5, 2016.
Burgess, D. O., Sharp, M. J., Mair, D. W., Dowdeswell, J. A., and Benham, T. J.: Flow dynamics and iceberg calving rates of Devon Ice Cap, Nunavut, Canada, J. Glaciol., 51, 219–230, https://doi.org/10.3189/172756505781829430, 2005.
Caldwell, T. G., Bibby, H. M., and Brown, C.: The magnetotelluric phase tensor, Geophys. J. Int., 158, 457–469, https://doi.org/10.1111/j.1365-246x.2004.02281.x, 2004.
Carter, S. P., Blankenship, D. D., Peters, M. E., Young, D. A., Holt, J. W., and Morse, D. L.: Radar-based subglacial lake classification in Antarctica, Geoche. Geophy. Geosy., 8, Q03016, https://doi.org/10.1029/2006gc001408, 2007.
Christner, B. C., Priscu, J. C., Achberger, A. M., Barbante, C., Carter, S. P., Christianson, K., Michaud, A. B., Mikucki, J. A., Mitchell, A. C., Skidmore, M. L., and Vick-Majors, T. J.: A microbial ecosystem beneath the West Antarctic ice sheet, Nature, 512, 310–313, https://doi.org/10.1038/nature13841, 2014.
Chu, W., Hilger, A. M., Culberg, R., Schroeder, D. M., Jordan, T. M., Seroussi, H., Young, D. A., Blankenship, D. D., and Vaughan, D. G.: Multisystem synthesis of radar sounding observations of the Amundsen Sea sector from the 2004–2005 field season, J. Geophys. Res.-Earth, 126, e2021JF006296, https://doi.org/10.1029/2021jf006296, 2021.
CReSIS: Operation IceBridge MCoRDS radar data (2011, 2012), Lawrence, Kansas, USA, Digital Media, http://data.cresis.ku.edu (last access: 26 January 2023), 2024.
Criscitiello, A. S., Geldsetzer, T., Rhodes, R. H., Arienzo, M., McConnell, J., Chellman, N., Osman, M. B., Yackel, J. J., and Marshall, S.: Marine Aerosol Records of Arctic Sea-Ice and Polynya Variability From New Ellesmere and Devon Island Firn Cores, Nunavut, Canada, J. Geophys. Res.-Oceans, 126, e2021JC017205, https://doi.org/10.1029/2021jc017205, 2021 (data available at: https://bit.ly/3k6UCua, last access: 26 January 2023).
Cuffey, K. M. and Paterson, W. S. B.: The physics of glaciers, Academic Press, https://doi.org/10.3189/002214311796405906, 2010.
Egbert, G. D.: Robust multiple-station magnetotelluric data processing, Geophys. J. Int., 130, 475–496, https://doi.org/10.1111/j.1365-246x.1997.tb05663.x, 1997.
Gades, A. M., Raymond, C. F., Conway, H., and Jagobel, R. W.: Bed Properties of Siple Dome and Adjacent Ice Streams, West Antarctica, Inferred from Radio-Echo Sounding Measurements, J. Glaciol. 46, 88–94, https://doi.org/10.3189/172756500781833467, 2000.
Gardner, A. S., Sharp, M. J., Koerner, R. M., Labine, C., Boon, S., Marshall, S. J., Burgess, D. O., and Lewis, D.: Near-Surface Temperature Lapse Rates over Arctic Glaciers and Their Implications for Temperature Downscaling, J. Climate. 22, 4281–4298, https://doi.org/10.1175/2009jcli2845.1, 2009.
Grasby, S. E., Jessop, A., Kelman, M., Ko, M., Chen, Z., Allen, D. M., Bell, S., Ferguson, G., Majorowicz, J., Moore, M., and Raymond, J.: Geothermal Energy Resource Potential of Canada, Geological Survey of Canada, Open File (Revised) 6914, https://doi.org/10.4095/291488, 2012.
Grombacher, D., Auken, E., Foged, N., Bording, T., Foley, N., Doran, P. T., Mikucki, J., Dugan, H. A., Garza-Giron, R., Myers, K., and Virginia, R. A.: Induced polarization effects in airborne transient electromagnetic data collected in the McMurdo Dry Valleys, Antarctica, Geophys. J. Int., 226, 1574–1583, https://doi.org/10.1093/gji/ggab148, 2021.
Gustafson, C. D., Key, K., Siegfried, M. R., Winberry, J. P., Fricker, H. A., Venturelli, R. A., and Michaud, A. B.: A dynamic saline groundwater system mapped beneath an Antarctic ice stream, Science, 376, 640–644, https://doi.org/10.1126/science.abm3301, 2022.
Hofstede, C., Wilhelms, F., Neckel, N., Fritzsche, D., Beyer, S., Hubbard, A., Pettersson, R., and Eisen, O.: The subglacial lake that wasn't there: Improved interpretation from seismic data reveals a sediment bedform at Isunnguata Sermia, J. Geophys. Res.-Earth, 128, e2022JF006850, https://doi.org/10.1029/2022jf006850, 2023.
Horgan, H. J., Anandakrishnan, S., Jacobel, R. W., Christianson, K., Alley, R. B., Heeszel, D. S., Picotti, S., and Walter, J. I.: Subglacial Lake Whillans – Seismic observations of a shallow active reservoir beneath a West Antarctic ice stream, Earth Planet. Sc. Lett., 331, 201–209, https://doi.org/10.1016/j.epsl.2012.02.023, 2012.
Horgan, H. J., van Haastrecht, L., Alley, R. B., Anandakrishnan, S., Beem, L. H., Christianson, K., Muto, A., and Siegfried, M. R.: Grounding zone subglacial properties from calibrated active-source seismic methods, The Cryosphere, 15, 1863–1880, https://doi.org/10.5194/tc-15-1863-2021, 2021.
Jordan, T. M., Bamber, J. L., Williams, C. N., Paden, J. D., Siegert, M. J., Huybrechts, P., Gagliardini, O., and Gillet-Chaulet, F.: An ice-sheet-wide framework for englacial attenuation from ice-penetrating radar data, The Cryosphere, 10, 1547–1570, https://doi.org/10.5194/tc-10-1547-2016, 2016.
Jordan, T. M., Cooper, M. A., Schroeder, D. M., Williams, C. N., Paden, J. D., Siegert, M. J., and Bamber, J. L.: Self-affine subglacial roughness: consequences for radar scattering and basal water discrimination in northern Greenland, The Cryosphere, 11, 1247–1264, https://doi.org/10.5194/tc-11-1247-2017, 2017.
Key, K. and Siegfried, M. R.: The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics, J. Glaciol., 63, 755–771, https://doi.org/10.1017/jog.2017.36, 2017.
Killingbeck, S. F., Booth, A. D., Livermore, P. W., Bates, C. R., and West, L. J.: Characterisation of subglacial water using a constrained transdimensional Bayesian transient electromagnetic inversion, Solid Earth, 11, 75–94, https://doi.org/10.5194/se-11-75-2020, 2020.
Killingbeck, S. F., Dow, C. F., and Unsworth, M. J.: A quantitative method for deriving salinity of subglacial water using ground-based transient electromagnetics, J. Glaciol., 68, 319–336, https://doi.org/10.1017/jog.2021.94, 2021.
Killingbeck, S. F., Unsworth, M. J., Rutishauser, A., Dubnick, A., Criscitiello, A. S., Killingbeck, J., Dow, C. F., Hill, T., Booth, A. D., Main, B., and Brossier, E.: Multi-technique surface geophysical surveys over Devon Ice Cap, Canadian Arctic, Zenodo [data set], https://doi.org/10.5281/zenodo.7641565, 2023.
King, E. C., Smith, A. M., Murray, T., and Stuart, G. W.: Glacier-bed characteristics of midtre Lovénbreen, Svalbard, from high-resolution seismic and radar surveying, J. Glaciol., 54, 145–156, https://doi.org/10.3189/002214308784409099, 2008.
King, M. S.: The influence of clay-sized particles on seismic velocity for Canadian Arctic permafrost, Can. J. Earth Sci., 21, 19–24, https://doi.org/10.1139/e84-003, 1984.
King, M. S., Zimmerman, R. W., and Corwin, R. F.: Seismic and electrical properties of unconsolidated Permafrost, Geophys. Prospect., 36, 349–364, https://doi.org/10.1111/j.1365-2478.1988.tb02168.x, 1988.
Kinnard, C., Zdanowicz, C. M., Fisher, D. A., and Wake, C. P.: Calibration of an ice-core glaciochemical (sea-salt) record with sea-ice variability in the Canadian Arctic, Ann. Glaciol., 44, 383–390, https://doi.org/10.3189/172756406781811349, 2006.
MacGregor, J. A., Winebrenner, D. P., Conway, H., Matsuoka, K., Mayewski, P. A., and Clow, G. D.: Modeling englacial radar attenuation at Siple Dome, West Antarctica, using ice chemistry and temperature data, J. Geophys. Res.-Earth, 112, F03008, https://doi.org/10.1029/2006jf000717, 2007.
MacGregor, J. A., Li, J., Paden, J. D., Catania, G. A., Clow, G. D., Fahnestock, M. A., Gogineni, S. P., Grimm, R. E., Morlighem, M., Nandi, S., and Seroussi, H.: Radar attenuation and temperature within the Greenland Ice Sheet, J. Geophys. Res.-Earth, 120, 983–1008, https://doi.org/10.1002/2014jf003418, 2015.
Maguire, R., Schmerr, N., Pettit, E., Riverman, K., Gardner, C., DellaGiustina, D. N., Avenson, B., Wagner, N., Marusiak, A. G., Habib, N., Broadbeck, J. I., Bray, V. J., and Bailey, S. H.: Geophysical constraints on the properties of a subglacial lake in northwest Greenland, The Cryosphere, 15, 3279–3291, https://doi.org/10.5194/tc-15-3279-2021, 2021.
Margrave, G. and Lamoureux, M.: Numerical Methods of Exploration Seismology: With Algorithms in MATLAB®, Cambridge, Cambridge University Press, https://doi.org/10.1017/9781316756041, 2019.
Matsuoka, K.: Pitfalls in radar diagnosis of ice-sheet bed conditions: Lessons from englacial attenuation models, Geophys. Res. Lett., 38, L05505, https://doi.org/10.1029/2010GL046205, 2011.
Mikucki, J. A., Auken, E., Tulaczyk, S., Virginia, R. A., Schamper, C., Sørensen, K. I., Doran, P. T., Dugan, H., and Foley, N.: Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley, Nat. Commun., 6, 6831, https://doi.org/10.1038/ncomms7831, 2015.
Pandit, B. I. and King, M. S.: A study of the effects of pore-water salinity on some physical properties of sedimentary rocks at permafrost temperatures, Can. J. Earth Sci., 16, 1566–1580, https://doi.org/10.1139/e79-143, 1979.
Paterson, W. S. B.: Vertical Strain-Rate Measurements in an Arctic Ice Cap and Deductions from Them, J. Glaciol., 17, 3–12, https://doi.org/10.3189/s0022143000030665, 1976.
Peters, L. E., Anandakrishnan, S., Holland, C. W., Horgan, H. J., Blankenship, D. D., and Voigt, D. E.: Seismic detection of a subglacial lake near the South Pole, Antarctica, Geophys. Res. Lett., 35, L23501, https://doi.org/10.1029/2008gl035704, 2008.
Prasad, M. and Dvorkin, J.: Velocity and attenuation of compressional waves in brines, in: SEG International Exposition and Annual Meeting, SEG-2004, https://doi.org/10.1190/1.1845150, 2004.
Priscu, J. C., Kalin, J., Winans, J., Campbell, T., Siegfried, M. R., Skidmore, M., Dore, J. E., Leventer, A., Harwood, D. M., Duling, D., and Zook, R.: Scientific access into Mercer Subglacial Lake: Scientific objectives, drilling operations and initial observations, Ann. Glaciol., 62, 340–352, https://doi.org/10.1017/aog.2021.10, 2021.
Reeh, N. and Paterson, W. S. B.: Application of a Flow Model to the Ice-Divide Region of Devon Island Ice Cap, Canada, J. Glaciol., 34, 55–63, https://doi.org/10.1017/s0022143000009060, 1988.
Rodi, W. and Mackie, R. L.: Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion, Geophysics, 66, 174–187, https://doi.org/10.1190/1.1444893, 2001.
Rutishauser, A.: Airborne radar-sounding investigations of the firn layer and subglacial environment of Devon Ice Cap, Nunavut, Canada, PhD Thesis, University of Alberta, Edmonton, https://doi.org/10.7939/r3-pxen-kq19, 2019.
Rutishauser, A., Blankenship, D. D., Sharp, M., Skidmore, M. L., Greenbaum, J. S., Grima, C., Schroeder, D. M., Dowdeswell, J. A., and Young, D. A.: Discovery of a hypersaline subglacial lake complex beneath DIC, Canadian Arctic, Sci. Adv., 4, 4, https://doi.org/10.1126/sciadv.aar4353, 2018.
Rutishauser, A., Blankenship, D. D., Young, D. A., Wolfenbarger, N. S., Beem, L. H., Skidmore, M. L., Dubnick, A., Criscitiello, A. S., Buhl, D. P., Richter, T. G., and Ng, G.: Data and derived products from airborne radar sounding survey over Devon Ice Cap, Canadian Arctic (1.0.0), Zenodo [data set], https://doi.org/10.5281/zenodo.5795105, 2021.
Rutishauser, A., Blankenship, D. D., Young, D. A., Wolfenbarger, N. S., Beem, L. H., Skidmore, M. L., Dubnick, A., and Criscitiello, A. S.: Radar sounding survey over Devon Ice Cap indicates the potential for a diverse hypersaline subglacial hydrological environment, The Cryosphere, 16, 379–395, https://doi.org/10.5194/tc-16-379-2022, 2022.
Schroeder, D. M., Grima, C., and Blankenship, D. D.: Evidence for variable grounding-zone and shear-margin basal conditions across Thwaites Glacier, West Antarctica Thwaites grounding zone and shear margin, Geophysics, 81, WA35–WA43, https://doi.org/10.1190/geo2015-0122.1, 2016a.
Schroeder, D. M., Seroussi, H., Chu, W., and Young, D. A.: Adaptively constraining radar attenuation and temperature across the Thwaites Glacier catchment using bed echoes, J. Glaciol., 62, 1075–1082, https://doi.org/10.1017/jog.2016.100, 2016b.
Smith, A. M., Woodward, J., Ross, N., Bentley, M. J., Hodgson, D. A., Siegert, M. J., and King, E. C.: Evidence for the long-term sedimentary environment in an Antarctic subglacial lake, Earth Planet. Sc. Lett., 504, 139–151, https://doi.org/10.1016/j.epsl.2018.10.011, 2018.
Tulaczyk, S. M. and Foley, N. T.: The role of electrical conductivity in radar wave reflection from glacier beds, The Cryosphere, 14, 4495–4506, https://doi.org/10.5194/tc-14-4495-2020, 2020.
Van Wychen, W., Burgess, D. O., Gray, L., Copland, L., Sharp, M., Dowdeswell, J. A., and Benham, T. J.: Glacier velocities and dynamic ice discharge from the Queen Elizabeth Islands, Nunavut, Canada, Geophys. Res. Lett., 41, 484–490, https://doi.org/10.1002/2013GL058558, 2014.
Van Wychen, W., Davis, J., Copland, L., Burgess, D. O., Gray, L., Sharp, M., Dowdeswell, J. A., and Benham, T. J.: Variability in ice motion and dynamic discharge from Devon Ice Cap, Nunavut, Canada, J. Glaciol., 63, 436–449, https://doi.org/10.1017/jog.2017.2, 2017.
Weidelt, P.: Response characteristics of coincident loop transient electromagnetic systems, Geophysics, 47, 1325–1330, https://doi.org/10.1190/1.1441393, 1982.
Short summary
A subglacial lake was proposed to exist beneath Devon Ice Cap in the Canadian Arctic based on the analysis of airborne data. Our study presents a new interpretation of the subglacial material beneath the Devon Ice Cap from surface-based geophysical data. We show that there is no evidence of subglacial water, and the subglacial lake has likely been misidentified. Re-evaluation of the airborne data shows that overestimation of a critical processing parameter has likely occurred in prior studies.
A subglacial lake was proposed to exist beneath Devon Ice Cap in the Canadian Arctic based on...