Articles | Volume 16, issue 9
https://doi.org/10.5194/tc-16-3575-2022
© Author(s) 2022. 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-16-3575-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
02 Sep 2022
Research article |
| 02 Sep 2022
| 02 Sep 2022
Persistent, extensive channelized drainage modeled beneath Thwaites Glacier, West Antarctica
Department of Earth Sciences, University of Oregon, Eugene, OR, USA
Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
Matthew J. Hoffman
Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
Stephen F. Price
Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, NM, USA
Dustin M. Schroeder
Department of Electrical Engineering, Stanford University, Stanford, CA, USA
Department of Geophysics, Stanford University, Stanford, CA, USA
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Mira Berdahl, Gunter Leguy, William H. Lipscomb, Nathan M. Urban, and Matthew J. Hoffman
The Cryosphere, 17, 1513–1543, https://doi.org/10.5194/tc-17-1513-2023, https://doi.org/10.5194/tc-17-1513-2023, 2023
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Contributions to future sea level from the Antarctic Ice Sheet remain poorly constrained. One reason is that ice sheet model initialization methods can have significant impacts on how the ice sheet responds to future forcings. We investigate the impacts of two key parameters used during model initialization. We find that these parameter choices alone can impact multi-century sea level rise by up to 2 m, emphasizing the need to carefully consider these choices for sea level rise predictions.
Trevor R. Hillebrand, Matthew J. Hoffman, Mauro Perego, Stephen F. Price, and Ian M. Howat
The Cryosphere, 16, 4679–4700, https://doi.org/10.5194/tc-16-4679-2022, https://doi.org/10.5194/tc-16-4679-2022, 2022
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We estimate that Humboldt Glacier, northern Greenland, will contribute 5.2–8.7 mm to global sea level in 2007–2100, using an ensemble of model simulations constrained by observations of glacier retreat and speedup. This is a significant fraction of the 40–140 mm from the whole Greenland Ice Sheet predicted by the recent ISMIP6 multi-model ensemble, suggesting that calibrating models against observed velocity changes could result in higher estimates of 21st century sea-level rise from Greenland.
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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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
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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.
Tun Jan Young, Carlos Martín, Poul Christoffersen, Dustin M. Schroeder, Slawek M. Tulaczyk, and Eliza J. Dawson
The Cryosphere, 15, 4117–4133, https://doi.org/10.5194/tc-15-4117-2021, https://doi.org/10.5194/tc-15-4117-2021, 2021
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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.
Tong Zhang, Stephen F. Price, Matthew J. Hoffman, Mauro Perego, and Xylar Asay-Davis
The Cryosphere, 14, 3407–3424, https://doi.org/10.5194/tc-14-3407-2020, https://doi.org/10.5194/tc-14-3407-2020, 2020
Hélène Seroussi, Sophie Nowicki, Antony J. Payne, Heiko Goelzer, William H. Lipscomb, Ayako Abe-Ouchi, Cécile Agosta, Torsten Albrecht, Xylar Asay-Davis, Alice Barthel, Reinhard Calov, Richard Cullather, Christophe Dumas, Benjamin K. Galton-Fenzi, Rupert Gladstone, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Tore Hattermann, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Nicolas C. Jourdain, Thomas Kleiner, Eric Larour, Gunter R. Leguy, Daniel P. Lowry, Chistopher M. Little, Mathieu Morlighem, Frank Pattyn, Tyler Pelle, Stephen F. Price, Aurélien Quiquet, Ronja Reese, Nicole-Jeanne Schlegel, Andrew Shepherd, Erika Simon, Robin S. Smith, Fiammetta Straneo, Sainan Sun, Luke D. Trusel, Jonas Van Breedam, Roderik S. W. van de Wal, Ricarda Winkelmann, Chen Zhao, Tong Zhang, and Thomas Zwinger
The Cryosphere, 14, 3033–3070, https://doi.org/10.5194/tc-14-3033-2020, https://doi.org/10.5194/tc-14-3033-2020, 2020
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The Antarctic ice sheet has been losing mass over at least the past 3 decades in response to changes in atmospheric and oceanic conditions. This study presents an ensemble of model simulations of the Antarctic evolution over the 2015–2100 period based on various ice sheet models, climate forcings and emission scenarios. Results suggest that the West Antarctic ice sheet will continue losing a large amount of ice, while the East Antarctic ice sheet could experience increased snow accumulation.
Adam M. Schneider, Charles S. Zender, and Stephen F. Price
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-247, https://doi.org/10.5194/gmd-2020-247, 2020
Preprint withdrawn
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We enhance the Energy Exascale Earth System Model's land
component (ELM) to better represent multi-year snow (firn) on ice sheets. Our
developments reveal ELM deficiencies regarding firn density, a fundamental
property in glaciology. To improve firn density profiles, we fine tune
ELM's snowpack parameters using statistical modeling. Our findings demonstrate
how ELM can simulate both seasonal snow and firn on ice sheets and advance a
broader effort to better predict sea level rise.
Anders Levermann, Ricarda Winkelmann, Torsten Albrecht, Heiko Goelzer, Nicholas R. Golledge, Ralf Greve, Philippe Huybrechts, Jim Jordan, Gunter Leguy, Daniel Martin, Mathieu Morlighem, Frank Pattyn, David Pollard, Aurelien Quiquet, Christian Rodehacke, Helene Seroussi, Johannes Sutter, Tong Zhang, Jonas Van Breedam, Reinhard Calov, Robert DeConto, Christophe Dumas, Julius Garbe, G. Hilmar Gudmundsson, Matthew J. Hoffman, Angelika Humbert, Thomas Kleiner, William H. Lipscomb, Malte Meinshausen, Esmond Ng, Sophie M. J. Nowicki, Mauro Perego, Stephen F. Price, Fuyuki Saito, Nicole-Jeanne Schlegel, Sainan Sun, and Roderik S. W. van de Wal
Earth Syst. Dynam., 11, 35–76, https://doi.org/10.5194/esd-11-35-2020, https://doi.org/10.5194/esd-11-35-2020, 2020
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We provide an estimate of the future sea level contribution of Antarctica from basal ice shelf melting up to the year 2100. The full uncertainty range in the warming-related forcing of basal melt is estimated and applied to 16 state-of-the-art ice sheet models using a linear response theory approach. The sea level contribution we obtain is very likely below 61 cm under unmitigated climate change until 2100 (RCP8.5) and very likely below 40 cm if the Paris Climate Agreement is kept.
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
Hélène Seroussi, Sophie Nowicki, Erika Simon, Ayako Abe-Ouchi, Torsten Albrecht, Julien Brondex, Stephen Cornford, Christophe Dumas, Fabien Gillet-Chaulet, Heiko Goelzer, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Thomas Kleiner, Eric Larour, Gunter Leguy, William H. Lipscomb, Daniel Lowry, Matthias Mengel, Mathieu Morlighem, Frank Pattyn, Anthony J. Payne, David Pollard, Stephen F. Price, Aurélien Quiquet, Thomas J. Reerink, Ronja Reese, Christian B. Rodehacke, Nicole-Jeanne Schlegel, Andrew Shepherd, Sainan Sun, Johannes Sutter, Jonas Van Breedam, Roderik S. W. van de Wal, Ricarda Winkelmann, and Tong Zhang
The Cryosphere, 13, 1441–1471, https://doi.org/10.5194/tc-13-1441-2019, https://doi.org/10.5194/tc-13-1441-2019, 2019
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We compare a wide range of Antarctic ice sheet simulations with varying initialization techniques and model parameters to understand the role they play on the projected evolution of this ice sheet under simple scenarios. Results are improved compared to previous assessments and show that continued improvements in the representation of the floating ice around Antarctica are critical to reduce the uncertainty in the future ice sheet contribution to sea level rise.
Katherine J. Evans, Joseph H. Kennedy, Dan Lu, Mary M. Forrester, Stephen Price, Jeremy Fyke, Andrew R. Bennett, Matthew J. Hoffman, Irina Tezaur, Charles S. Zender, and Miren Vizcaíno
Geosci. Model Dev., 12, 1067–1086, https://doi.org/10.5194/gmd-12-1067-2019, https://doi.org/10.5194/gmd-12-1067-2019, 2019
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A robust validation of ice sheet models is presented using LIVVkit, version 2.1. It targets ice sheet and coupled Earth system models, and handles datasets and operations that require high-performance computing and storage. We apply LIVVkit to a Greenland ice sheet simulation to show the degree to which it captures the surface mass balance. LIVVkit identifies a positive bias due to insufficient melting compared to observations that is focused largely around Greenland's southwest region.
William H. Lipscomb, Stephen F. Price, Matthew J. Hoffman, Gunter R. Leguy, Andrew R. Bennett, Sarah L. Bradley, Katherine J. Evans, Jeremy G. Fyke, Joseph H. Kennedy, Mauro Perego, Douglas M. Ranken, William J. Sacks, Andrew G. Salinger, Lauren J. Vargo, and Patrick H. Worley
Geosci. Model Dev., 12, 387–424, https://doi.org/10.5194/gmd-12-387-2019, https://doi.org/10.5194/gmd-12-387-2019, 2019
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This paper describes the Community Ice Sheet Model (CISM) version 2.1. CISM solves equations for ice flow, heat conduction, surface melting, and other processes such as basal sliding and iceberg calving. It can be used for ice-sheet-only simulations or as the ice sheet component of the Community Earth System Model. Model solutions have been verified for standard test problems. CISM can efficiently simulate the whole Greenland ice sheet, with results that are broadly consistent with observations.
Matthew J. Hoffman, Mauro Perego, Stephen F. Price, William H. Lipscomb, Tong Zhang, Douglas Jacobsen, Irina Tezaur, Andrew G. Salinger, Raymond Tuminaro, and Luca Bertagna
Geosci. Model Dev., 11, 3747–3780, https://doi.org/10.5194/gmd-11-3747-2018, https://doi.org/10.5194/gmd-11-3747-2018, 2018
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MPAS-Albany Land Ice (MALI) is a new variable-resolution land ice model that uses unstructured grids on a plane or sphere. MALI is built for Earth system modeling on high-performance computing platforms using existing software libraries. MALI simulates the evolution of ice thickness, velocity, and temperature, and it includes schemes for simulating iceberg calving and the flow of water beneath ice sheets and its effect on ice sliding. The model is demonstrated for the Antarctic ice sheet.
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.
Tong Zhang, Stephen Price, Lili Ju, Wei Leng, Julien Brondex, Gaël Durand, and Olivier Gagliardini
The Cryosphere, 11, 179–190, https://doi.org/10.5194/tc-11-179-2017, https://doi.org/10.5194/tc-11-179-2017, 2017
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Stokes-flow models are the highest-fidelity representation of the equations governing ice sheet flow and they are often treated as the standard against which other models are compared in model benchmark activities. We compare two different Stokes models applied to a canonical set of idealized marine ice sheet experiments and demonstrate that the solutions converge with increasing grid resolution. This provides confidence in the use of Stokes models for generating test case solution metrics.
Stephen F. Price, Matthew J. Hoffman, Jennifer A. Bonin, Ian M. Howat, Thomas Neumann, Jack Saba, Irina Tezaur, Jeffrey Guerber, Don P. Chambers, Katherine J. Evans, Joseph H. Kennedy, Jan Lenaerts, William H. Lipscomb, Mauro Perego, Andrew G. Salinger, Raymond S. Tuminaro, Michiel R. van den Broeke, and Sophie M. J. Nowicki
Geosci. Model Dev., 10, 255–270, https://doi.org/10.5194/gmd-10-255-2017, https://doi.org/10.5194/gmd-10-255-2017, 2017
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We introduce the Cryospheric Model Comparison Tool (CmCt) and propose qualitative and quantitative metrics for evaluating ice sheet model simulations against observations. Greenland simulations using the Community Ice Sheet Model are compared to gravimetry and altimetry observations from 2003 to 2013. We show that the CmCt can be used to score simulations of increasing complexity relative to observations of dynamic change in Greenland over the past decade.
S. de la Peña, I. M. Howat, P. W. Nienow, M. R. van den Broeke, E. Mosley-Thompson, S. F. Price, D. Mair, B. Noël, and A. J. Sole
The Cryosphere, 9, 1203–1211, https://doi.org/10.5194/tc-9-1203-2015, https://doi.org/10.5194/tc-9-1203-2015, 2015
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This paper presents an assessment of changes in the near-surface structure of the accumulation zone of the Greenland Ice Sheet caused by an increase of melt at higher elevations in the last decade, especially during the unusually warm years of 2010 and 2012. The increase in melt and firn densification complicate the interpretation of changes in the ice volume, and the observed increase in firn ice content may reduce the important meltwater buffering capacity of the Greenland Ice Sheet.
I. K. Tezaur, M. Perego, A. G. Salinger, R. S. Tuminaro, and S. F. Price
Geosci. Model Dev., 8, 1197–1220, https://doi.org/10.5194/gmd-8-1197-2015, https://doi.org/10.5194/gmd-8-1197-2015, 2015
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In this manuscript, we discuss the development and validation of a new momentum balance solver for modeling the flow of glaciers and ice sheets based on the 1st-order Stokes equations. We demonstrate the numerical convergence of our solver (with respect to computational mesh spacing), its flexibility (with respect to both the choice of mesh and finite element type), and its computational performance (robustness and scalability when applied to both idealized and realistic ice sheet simulations).
M. P. Lüthi, C. Ryser, L. C. Andrews, G. A. Catania, M. Funk, R. L. Hawley, M. J. Hoffman, and T. A. Neumann
The Cryosphere, 9, 245–253, https://doi.org/10.5194/tc-9-245-2015, https://doi.org/10.5194/tc-9-245-2015, 2015
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We analyze the thermal structure of the Greenland Ice Sheet with a heat flow model. New borehole measurements indicate that more heat is stored within the ice than would be expected from heat diffusion alone. We conclude that temperate paleo-firn and cyro-hydrologic warming are essential processes that explain the measurements.
T. L. Edwards, X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, J. M. Gregory, M. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. Price, A. Quiquet, and C. Ritz
The Cryosphere, 8, 181–194, https://doi.org/10.5194/tc-8-181-2014, https://doi.org/10.5194/tc-8-181-2014, 2014
T. L. Edwards, X. Fettweis, O. Gagliardini, F. Gillet-Chaulet, H. Goelzer, J. M. Gregory, M. Hoffman, P. Huybrechts, A. J. Payne, M. Perego, S. Price, A. Quiquet, and C. Ritz
The Cryosphere, 8, 195–208, https://doi.org/10.5194/tc-8-195-2014, https://doi.org/10.5194/tc-8-195-2014, 2014
B. F. Morriss, R. L. Hawley, J. W. Chipman, L. C. Andrews, G. A. Catania, M. J. Hoffman, M. P. Lüthi, and T. A. Neumann
The Cryosphere, 7, 1869–1877, https://doi.org/10.5194/tc-7-1869-2013, https://doi.org/10.5194/tc-7-1869-2013, 2013
W. Leng, L. Ju, M. Gunzburger, and S. Price
The Cryosphere, 7, 19–29, https://doi.org/10.5194/tc-7-19-2013, https://doi.org/10.5194/tc-7-19-2013, 2013
Related subject area
Discipline: Glaciers | Subject: Subglacial Processes
Multi-scale variations of subglacial hydro-mechanical conditions at Kongsvegen glacier, Svalbard
Geothermal heat source estimations through ice flow modelling at Mýrdalsjökull, Iceland
Impact of shallow sills on circulation regimes and submarine melting in glacial fjords
Differential impact of isolated topographic bumps on ice sheet flow and subglacial processes
Channelized, distributed, and disconnected: spatial structure and temporal evolution of the subglacial drainage under a valley glacier in the Yukon
Long-period variability in ice-dammed glacier outburst floods due to evolving catchment geometry
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow
Brief communication: Heterogenous thinning and subglacial lake activity on Thwaites Glacier, West Antarctica
Subglacial permafrost dynamics and erosion inside subglacial channels driven by surface events in Svalbard
Quantification of seasonal and diurnal dynamics of subglacial channels using seismic observations on an Alpine glacier
Glaciohydraulic seismic tremors on an Alpine glacier
Airborne radionuclides and heavy metals in high Arctic terrestrial environment as the indicators of sources and transfers of contamination
Pervasive cold ice within a temperate glacier – implications for glacier thermal regimes, sediment transport and foreland geomorphology
Coline Bouchayer, Ugo Nanni, Pierre-Marie Lefeuvre, John Hult, Louise Steffensen Schmidt, Jack Kohler, François Renard, and Thomas V. Schuler
The Cryosphere, 18, 2939–2968, https://doi.org/10.5194/tc-18-2939-2024, https://doi.org/10.5194/tc-18-2939-2024, 2024
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We explore the interplay between surface runoff and subglacial conditions. We focus on Kongsvegen glacier in Svalbard. We drilled 350 m down to the glacier base to measure water pressure, till strength, seismic noise, and glacier surface velocity. In the low-melt season, the drainage system adapted gradually, while the high-melt season led to a transient response, exceeding drainage capacity and enhancing sliding. Our findings contribute to discussions on subglacial hydro-mechanical processes.
Alexander H. Jarosch, Eyjólfur Magnússon, Krista Hannesdóttir, Joaquín M. C. Belart, and Finnur Pálsson
The Cryosphere, 18, 2443–2454, https://doi.org/10.5194/tc-18-2443-2024, https://doi.org/10.5194/tc-18-2443-2024, 2024
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Geothermally active regions beneath glaciers not only influence local ice flow as well as the mass balance of glaciers but also control changes of subglacial water reservoirs and possible subsequent glacier lake outburst floods. In Iceland, such outburst floods impose danger to people and infrastructure and are therefore monitored. We present a novel computer-simulation-supported method to estimate the activity of such geothermal areas and to monitor its evolution.
Weiyang Bao and Carlos Moffat
The Cryosphere, 18, 187–203, https://doi.org/10.5194/tc-18-187-2024, https://doi.org/10.5194/tc-18-187-2024, 2024
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A shallow sill can promote the downward transport of the upper-layer freshwater outflow in proglacial fjords. This sill-driven transport reduces fjord temperature and stratification. The sill depth, freshwater discharge, fjord temperature, and stratification are key parameters that modulate the heat supply towards glaciers. Additionally, the relative depth of the plume outflow, the fjord, and the sill can be used to characterize distinct circulation and heat transport regimes in glacial fjords.
Marion A. McKenzie, Lauren E. Miller, Jacob S. Slawson, Emma J. MacKie, and Shujie Wang
The Cryosphere, 17, 2477–2486, https://doi.org/10.5194/tc-17-2477-2023, https://doi.org/10.5194/tc-17-2477-2023, 2023
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Topographic highs (“bumps”) across glaciated landscapes have the potential to affect glacial ice. Bumps in the deglaciated Puget Lowland are assessed for streamlined glacial features to provide insight on ice–bed interactions. We identify a general threshold in which bumps significantly disrupt ice flow and sedimentary processes in this location. However, not all bumps have the same degree of impact. The system assessed here has relevance to parts of the Greenland Ice Sheet and Thwaites Glacier.
Camilo Andrés Rada Giacaman and Christian Schoof
The Cryosphere, 17, 761–787, https://doi.org/10.5194/tc-17-761-2023, https://doi.org/10.5194/tc-17-761-2023, 2023
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Water flowing at the base of glaciers plays a crucial role in controlling the speed at which glaciers move and how glaciers react to climate. The processes happening below the glaciers are extremely hard to observe and remain only partially understood. Here we provide novel insight into the subglacial environment based on an extensive dataset with over 300 boreholes on an alpine glacier in the Yukon Territory. We highlight the importance of hydraulically disconnected regions of the glacier bed.
Amy Jenson, Jason M. Amundson, Jonathan Kingslake, and Eran Hood
The Cryosphere, 16, 333–347, https://doi.org/10.5194/tc-16-333-2022, https://doi.org/10.5194/tc-16-333-2022, 2022
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Outburst floods are sudden releases of water from glacial environments. As glaciers retreat, changes in glacier and basin geometry impact outburst flood characteristics. We combine a glacier flow model describing glacier retreat with an outburst flood model to explore how ice dam height, glacier length, and remnant ice in a basin influence outburst floods. We find storage capacity is the greatest indicator of flood magnitude, and the flood onset mechanism is a significant indicator of duration.
Anna Derkacheva, Fabien Gillet-Chaulet, Jeremie Mouginot, Eliot Jager, Nathan Maier, and Samuel Cook
The Cryosphere, 15, 5675–5704, https://doi.org/10.5194/tc-15-5675-2021, https://doi.org/10.5194/tc-15-5675-2021, 2021
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Along the edges of the Greenland Ice Sheet surface melt lubricates the bed and causes large seasonal fluctuations in ice speeds during summer. Accurately understanding how these ice speed changes occur is difficult due to the inaccessibility of the glacier bed. We show that by using surface velocity maps with high temporal resolution and numerical modelling we can infer the basal conditions that control seasonal fluctuations in ice speed and gain insight into seasonal dynamics over large areas.
Andrew O. Hoffman, Knut Christianson, Daniel Shapero, Benjamin E. Smith, and Ian Joughin
The Cryosphere, 14, 4603–4609, https://doi.org/10.5194/tc-14-4603-2020, https://doi.org/10.5194/tc-14-4603-2020, 2020
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The West Antarctic Ice Sheet has long been considered geometrically prone to collapse, and Thwaites Glacier, the largest glacier in the Amundsen Sea, is likely in the early stages of disintegration. Using observations of Thwaites Glacier velocity and elevation change, we show that the transport of ~2 km3 of water beneath Thwaites Glacier has only a small and transient effect on glacier speed relative to ongoing thinning driven by ocean melt.
Andreas Alexander, Jaroslav Obu, Thomas V. Schuler, Andreas Kääb, and Hanne H. Christiansen
The Cryosphere, 14, 4217–4231, https://doi.org/10.5194/tc-14-4217-2020, https://doi.org/10.5194/tc-14-4217-2020, 2020
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In this study we present subglacial air, ice and sediment temperatures from within the basal drainage systems of two cold-based glaciers on Svalbard during late spring and the summer melt season. We put the data into the context of air temperature and rainfall at the glacier surface and show the importance of surface events on the subglacial thermal regime and erosion around basal drainage channels. Observed vertical erosion rates thereby reachup to 0.9 m d−1.
Ugo Nanni, Florent Gimbert, Christian Vincent, Dominik Gräff, Fabian Walter, Luc Piard, and Luc Moreau
The Cryosphere, 14, 1475–1496, https://doi.org/10.5194/tc-14-1475-2020, https://doi.org/10.5194/tc-14-1475-2020, 2020
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Our study addresses key questions on the subglacial drainage system physics through a novel observational approach that overcomes traditional limitations. We conducted, over 2 years, measurements of the subglacial water-flow-induced seismic noise and of glacier basal sliding speeds. We then inverted for the subglacial channel's hydraulic pressure gradient and hydraulic radius and investigated the links between the equilibrium state of subglacial channels and glacier basal sliding.
Fabian Lindner, Fabian Walter, Gabi Laske, and Florent Gimbert
The Cryosphere, 14, 287–308, https://doi.org/10.5194/tc-14-287-2020, https://doi.org/10.5194/tc-14-287-2020, 2020
Edyta Łokas, Agata Zaborska, Ireneusz Sobota, Paweł Gaca, J. Andrew Milton, Paweł Kocurek, and Anna Cwanek
The Cryosphere, 13, 2075–2086, https://doi.org/10.5194/tc-13-2075-2019, https://doi.org/10.5194/tc-13-2075-2019, 2019
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Cryoconite granules built of mineral particles, organic substances and living organisms significantly influence fluxes of energy and matter at glacier surfaces. They contribute to ice melting, give rise to an exceptional ecosystem, and effectively trap contaminants. This study evaluates contamination levels of radionuclides in cryoconite from Arctic glaciers and identifies sources of this contamination, proving that cryoconite is an excellent indicator of atmospheric contamination.
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.
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Short summary
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.
The presence of water beneath glaciers is a control on glacier speed and ocean-caused melting,...
