Articles | Volume 17, issue 7
https://doi.org/10.5194/tc-17-2607-2023
© Author(s) 2023. 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-17-2607-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
04 Jul 2023
Research article |
| 04 Jul 2023
| 04 Jul 2023
The impact of surface melt rate and catchment characteristics on Greenland Ice Sheet moulin inputs
Tim Hill
CORRESPONDING AUTHOR
Department of Applied Mathematics, University of Waterloo, Waterloo, Canada
current address: Department of Earth Sciences, Simon Fraser University, Burnaby, Canada
Christine F. Dow
Department of Applied Mathematics, University of Waterloo, Waterloo, Canada
Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada
Related authors
Tim Hill, Derek Bingham, Gwenn E. Flowers, and Matthew J. Hoffman
Geosci. Model Dev., 18, 4045–4074, https://doi.org/10.5194/gmd-18-4045-2025, https://doi.org/10.5194/gmd-18-4045-2025, 2025
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Subglacial drainage models represent water flow beneath glaciers and ice sheets. Here, we train fast statistical models called Gaussian process (GP) emulators to accelerate subglacial drainage modelling by ~ 1000 times. We use the fast emulator predictions to show that three of the model parameters are responsible for > 90 % of the variance in model outputs. The fast GP emulators will enable future uncertainty quantification and calibration of these models.
Siobhan F. Killingbeck, Anja Rutishauser, Martyn J. Unsworth, Ashley Dubnick, Alison S. Criscitiello, James Killingbeck, Christine F. Dow, Tim Hill, Adam D. Booth, Brittany Main, and Eric Brossier
The Cryosphere, 18, 3699–3722, https://doi.org/10.5194/tc-18-3699-2024, https://doi.org/10.5194/tc-18-3699-2024, 2024
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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.
Tim Hill, Derek Bingham, Gwenn E. Flowers, and Matthew J. Hoffman
Geosci. Model Dev., 18, 4045–4074, https://doi.org/10.5194/gmd-18-4045-2025, https://doi.org/10.5194/gmd-18-4045-2025, 2025
Short summary
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Subglacial drainage models represent water flow beneath glaciers and ice sheets. Here, we train fast statistical models called Gaussian process (GP) emulators to accelerate subglacial drainage modelling by ~ 1000 times. We use the fast emulator predictions to show that three of the model parameters are responsible for > 90 % of the variance in model outputs. The fast GP emulators will enable future uncertainty quantification and calibration of these models.
Laurane Charrier, Amaury Dehecq, Lei Guo, Fanny Brun, Romain Millan, Nathan Lioret, Luke Copland, Nathan Maier, Christine Dow, and Paul Halas
EGUsphere, https://doi.org/10.5194/egusphere-2024-3409, https://doi.org/10.5194/egusphere-2024-3409, 2025
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While global annual glacier velocities are openly accessible, sub-annual velocity time series are still lacking. This hinders our ability to understand flow processes and the integration of these observations in numerical models. We introduce an open source Python package called TICOI to fuses multi-temporal and multi-sensor image-pair velocities produced by different processing chains to produce standardized sub-annual velocity products.
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.
Siobhan F. Killingbeck, Anja Rutishauser, Martyn J. Unsworth, Ashley Dubnick, Alison S. Criscitiello, James Killingbeck, Christine F. Dow, Tim Hill, Adam D. Booth, Brittany Main, and Eric Brossier
The Cryosphere, 18, 3699–3722, https://doi.org/10.5194/tc-18-3699-2024, https://doi.org/10.5194/tc-18-3699-2024, 2024
Short summary
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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.
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.
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.
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.
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.
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.
Related subject area
Discipline: Glaciers | Subject: Glacier Hydrology
Modeling saline-fluid flow through subglacial channels
Assessing supraglacial lake depth using ICESat-2, Sentinel-2, TanDEM-X, and in situ sonar measurements over Northeast and Southwest Greenland
Hydrological response of Andean catchments to recent glacier mass loss
Characterizing sub-glacial hydrology using radar simulations
Velocity variations and hydrological drainage at Baltoro Glacier, Pakistan
Seasonal to decadal dynamics of supraglacial lakes on debris-covered glaciers in the Khumbu region, Nepal
A conceptual model for glacial lake bathymetric distribution
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 1: Steady states and friction laws
The evolution of isolated cavities and hydraulic connection at the glacier bed – Part 2: A dynamic viscoelastic model
Evaporation over a glacial lake in Antarctica
A local model of snow–firn dynamics and application to the Colle Gnifetti site
Accumulation of legacy fallout radionuclides in cryoconite on Isfallsglaciären (Arctic Sweden) and their downstream spatial distribution
Drainage of an ice-dammed lake through a supraglacial stream: hydraulics and thermodynamics
Development of a subglacial lake monitored with radio-echo sounding: case study from the eastern Skaftá cauldron in the Vatnajökull ice cap, Iceland
Geophysical constraints on the properties of a subglacial lake in northwest Greenland
Gulf of Alaska ice-marginal lake area change over the Landsat record and potential physical controls
Sensitivity of subglacial drainage to water supply distribution at the Kongsfjord basin, Svalbard
Buoyant calving and ice-contact lake evolution at Pasterze Glacier (Austria) in the period 1998–2019
An analysis of instabilities and limit cycles in glacier-dammed reservoirs
Coupled modelling of subglacial hydrology and calving-front melting at Store Glacier, West Greenland
Channelized, distributed, and disconnected: subglacial drainage under a valley glacier in the Yukon
Amy Jenson, Mark Skidmore, Lucas Beem, Martin Truffer, and Scott McCalla
The Cryosphere, 18, 5451–5464, https://doi.org/10.5194/tc-18-5451-2024, https://doi.org/10.5194/tc-18-5451-2024, 2024
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Water in some glacier environments contains salt, which increases its density and lowers its freezing point, allowing saline water to exist where freshwater cannot. Previous subglacial hydrology models do not consider saline fluid. We model the flow of saline fluid from a subglacial lake through a circular channel at the glacier bed, finding that higher salinities lead to less melting at the channel walls and lower discharge rates. We also observe the impact of increased fluid density on flow.
Katrina Lutz, Lily Bever, Christian Sommer, Thorsten Seehaus, Angelika Humbert, Mirko Scheinert, and Matthias Braun
The Cryosphere, 18, 5431–5449, https://doi.org/10.5194/tc-18-5431-2024, https://doi.org/10.5194/tc-18-5431-2024, 2024
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The estimation of the amount of water found within supraglacial lakes is important for understanding how much water is lost from glaciers each year. Here, we develop two new methods for estimating supraglacial lake volume that can be easily applied on a large scale. Furthermore, we compare these methods to two previously developed methods in order to determine when it is best to use each method. Finally, three of these methods are applied to peak melt dates over an area in Northeast Greenland.
Alexis Caro, Thomas Condom, Antoine Rabatel, Nicolas Champollion, Nicolás García, and Freddy Saavedra
The Cryosphere, 18, 2487–2507, https://doi.org/10.5194/tc-18-2487-2024, https://doi.org/10.5194/tc-18-2487-2024, 2024
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The glacier runoff changes are still unknown in most of the Andean catchments, thereby increasing uncertainties in estimating water availability, especially during the dry season. Here, we simulate glacier evolution and related glacier runoff changes across the Andes between 2000 and 2019. Our results indicate a glacier reduction in 93 % of the catchments, leading to a 12 % increase in glacier melt. These results can be downloaded and integrated with discharge measurements in each catchment.
Chris Pierce, Christopher Gerekos, Mark Skidmore, Lucas Beem, Don Blankenship, Won Sang Lee, Ed Adams, Choon-Ki Lee, and Jamey Stutz
The Cryosphere, 18, 1495–1515, https://doi.org/10.5194/tc-18-1495-2024, https://doi.org/10.5194/tc-18-1495-2024, 2024
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Water beneath glaciers in Antarctica can influence how the ice slides or melts. Airborne radar can detect this water, which looks bright in radar images. However, common techniques cannot identify the water's size or shape. We used a simulator to show how the radar image changes based on the bed material, size, and shape of the waterbody. This technique was applied to a suspected waterbody beneath Thwaites Glacier. We found it may be consistent with a series of wide, flat canals or a lake.
Anna Wendleder, Jasmin Bramboeck, Jamie Izzard, Thilo Erbertseder, Pablo d'Angelo, Andreas Schmitt, Duncan J. Quincey, Christoph Mayer, and Matthias H. Braun
The Cryosphere, 18, 1085–1103, https://doi.org/10.5194/tc-18-1085-2024, https://doi.org/10.5194/tc-18-1085-2024, 2024
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This study analyses the basal sliding and the hydrological drainage of Baltoro Glacier, Pakistan. The surface velocity was characterized by a spring speed-up, summer peak, and autumn speed-up. Snow melt has the largest impact on the spring speed-up, summer velocity peak, and the transition from inefficient to efficient drainage. Drainage from supraglacial lakes contributed to the fall speed-up. Increased summer temperatures will intensify the magnitude of meltwater and thus surface velocities.
Lucas Zeller, Daniel McGrath, Scott W. McCoy, and Jonathan Jacquet
The Cryosphere, 18, 525–541, https://doi.org/10.5194/tc-18-525-2024, https://doi.org/10.5194/tc-18-525-2024, 2024
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In this study we developed methods for automatically identifying supraglacial lakes in multiple satellite imagery sources for eight glaciers in Nepal. We identified a substantial seasonal variability in lake area, which was as large as the variability seen across entire decades. These complex patterns are not captured in existing regional-scale datasets. Our findings show that this seasonal variability must be accounted for in order to interpret long-term changes in debris-covered glaciers.
Taigang Zhang, Weicai Wang, and Baosheng An
The Cryosphere, 17, 5137–5154, https://doi.org/10.5194/tc-17-5137-2023, https://doi.org/10.5194/tc-17-5137-2023, 2023
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Detailed glacial lake bathymetry surveys are essential for accurate glacial lake outburst flood (GLOF) simulation and risk assessment. We creatively developed a conceptual model for glacial lake bathymetric distribution. The basic idea is that the statistical glacial lake volume–area curves conform to a power-law relationship indicating that the idealized geometric shape of the glacial lake basin should be hemispheres or cones.
Christian Schoof
The Cryosphere, 17, 4797–4815, https://doi.org/10.5194/tc-17-4797-2023, https://doi.org/10.5194/tc-17-4797-2023, 2023
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Computational models that seek to predict the future behaviour of ice sheets and glaciers typically rely on being able to compute the rate at which a glacier slides over its bed. In this paper, I show that the degree to which the glacier bed is
hydraulically connected(how easily water can flow along the glacier bed) plays a central role in determining how fast ice can slide.
Christian Schoof
The Cryosphere, 17, 4817–4836, https://doi.org/10.5194/tc-17-4817-2023, https://doi.org/10.5194/tc-17-4817-2023, 2023
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The subglacial drainage of meltwater plays a major role in regulating glacier and ice sheet flow. In this paper, I construct and solve a mathematical model that describes how connections are made within the subglacial drainage system. This will aid future efforts to predict glacier response to surface melt supply.
Elena Shevnina, Miguel Potes, Timo Vihma, Tuomas Naakka, Pankaj Ramji Dhote, and Praveen Kumar Thakur
The Cryosphere, 16, 3101–3121, https://doi.org/10.5194/tc-16-3101-2022, https://doi.org/10.5194/tc-16-3101-2022, 2022
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The evaporation over an ice-free glacial lake was measured in January 2018, and the uncertainties inherent to five indirect methods were quantified. Results show that in summer up to 5 mm of water evaporated daily from the surface of the lake located in Antarctica. The indirect methods underestimated the evaporation over the lake's surface by up to 72 %. The results are important for estimating the evaporation over polar regions where a growing number of glacial lakes have recently been evident.
Fabiola Banfi and Carlo De Michele
The Cryosphere, 16, 1031–1056, https://doi.org/10.5194/tc-16-1031-2022, https://doi.org/10.5194/tc-16-1031-2022, 2022
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Climate changes require a dynamic description of glaciers in hydrological models. In this study we focus on the local modelling of snow and firn. We tested our model at the site of Colle Gnifetti, 4400–4550 m a.s.l. The model shows that wind erodes all the precipitation of the cold months, while snow is in part conserved between April and September since higher temperatures protect snow from erosion. We also compared modelled and observed firn density, obtaining a satisfying agreement.
Caroline C. Clason, Will H. Blake, Nick Selmes, Alex Taylor, Pascal Boeckx, Jessica Kitch, Stephanie C. Mills, Giovanni Baccolo, and Geoffrey E. Millward
The Cryosphere, 15, 5151–5168, https://doi.org/10.5194/tc-15-5151-2021, https://doi.org/10.5194/tc-15-5151-2021, 2021
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Our paper presents results of sample collection and subsequent geochemical analyses from the glaciated Isfallsglaciären catchment in Arctic Sweden. The data suggest that material found on the surface of glaciers,
cryoconite, is very efficient at accumulating products of nuclear fallout transported in the atmosphere following events such as the Chernobyl disaster. We investigate how this compares with samples in the downstream environment and consider potential environmental implications.
Christophe Ogier, Mauro A. Werder, Matthias Huss, Isabelle Kull, David Hodel, and Daniel Farinotti
The Cryosphere, 15, 5133–5150, https://doi.org/10.5194/tc-15-5133-2021, https://doi.org/10.5194/tc-15-5133-2021, 2021
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Glacier-dammed lakes are prone to draining rapidly when the ice dam breaks and constitute a serious threat to populations downstream. Such a lake drainage can proceed through an open-air channel at the glacier surface. In this study, we present what we believe to be the most complete dataset to date of an ice-dammed lake drainage through such an open-air channel. We provide new insights for future glacier-dammed lake drainage modelling studies and hazard assessments.
Eyjólfur Magnússon, Finnur Pálsson, Magnús T. Gudmundsson, Thórdís Högnadóttir, Cristian Rossi, Thorsteinn Thorsteinsson, Benedikt G. Ófeigsson, Erik Sturkell, and Tómas Jóhannesson
The Cryosphere, 15, 3731–3749, https://doi.org/10.5194/tc-15-3731-2021, https://doi.org/10.5194/tc-15-3731-2021, 2021
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We present a unique insight into the shape and development of a subglacial lake over a 7-year period, using repeated radar survey. The lake collects geothermal meltwater, which is released in semi-regular floods, often referred to as jökulhlaups. The applicability of our survey approach to monitor the water stored in the lake for a better assessment of the potential hazard of jökulhlaups is demonstrated by comparison with independent measurements of released water volume during two jökulhlaups.
Ross Maguire, Nicholas Schmerr, Erin Pettit, Kiya Riverman, Christyna Gardner, Daniella N. DellaGiustina, Brad Avenson, Natalie Wagner, Angela G. Marusiak, Namrah Habib, Juliette I. Broadbeck, Veronica J. Bray, and Samuel H. Bailey
The Cryosphere, 15, 3279–3291, https://doi.org/10.5194/tc-15-3279-2021, https://doi.org/10.5194/tc-15-3279-2021, 2021
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In the last decade, airborne radar surveys have revealed the presence of lakes below the Greenland ice sheet. However, little is known about their properties, including their depth and the volume of water they store. We performed a ground-based geophysics survey in northwestern Greenland and, for the first time, were able to image the depth of a subglacial lake and estimate its volume. Our findings have implications for the thermal state and stability of the ice sheet in northwest Greenland.
Hannah R. Field, William H. Armstrong, and Matthias Huss
The Cryosphere, 15, 3255–3278, https://doi.org/10.5194/tc-15-3255-2021, https://doi.org/10.5194/tc-15-3255-2021, 2021
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The growth of a glacier lake alters the hydrology, ecology, and glaciology of its surrounding region. We investigate modern glacier lake area change across northwestern North America using repeat satellite imagery. Broadly, we find that lakes downstream from glaciers grew, while lakes dammed by glaciers shrunk. Our results suggest that the shape of the landscape surrounding a glacier lake plays a larger role in determining how quickly a lake changes than climatic or glaciologic factors.
Chloé Scholzen, Thomas V. Schuler, and Adrien Gilbert
The Cryosphere, 15, 2719–2738, https://doi.org/10.5194/tc-15-2719-2021, https://doi.org/10.5194/tc-15-2719-2021, 2021
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We use a two-dimensional model of water flow below the glaciers in Kongsfjord, Svalbard, to investigate how different processes of surface-to-bed meltwater transfer affect subglacial hydraulic conditions. The latter are important for the sliding motion of glaciers, which in some cases exhibit huge variations. Our findings indicate that the glaciers in our study area undergo substantial sliding because water is poorly evacuated from their base, with limited influence from the surface hydrology.
Andreas Kellerer-Pirklbauer, Michael Avian, Douglas I. Benn, Felix Bernsteiner, Philipp Krisch, and Christian Ziesler
The Cryosphere, 15, 1237–1258, https://doi.org/10.5194/tc-15-1237-2021, https://doi.org/10.5194/tc-15-1237-2021, 2021
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Present climate warming leads to glacier recession and formation of lakes. We studied the nature and rate of lake evolution in the period 1998–2019 at Pasterze Glacier, Austria. We detected for instance several large-scale and rapidly occurring ice-breakup events from below the water level. This process, previously not reported from the European Alps, might play an important role at alpine glaciers in the future as many glaciers are expected to recede into valley basins allowing lake formation.
Christian Schoof
The Cryosphere, 14, 3175–3194, https://doi.org/10.5194/tc-14-3175-2020, https://doi.org/10.5194/tc-14-3175-2020, 2020
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Glacier lake outburst floods are major glacial hazards in which ice-dammed reservoirs rapidly drain, often in a recurring fashion. The main flood phase typically involves a growing channel being eroded into ice by water flow. What is poorly understood is how that channel first comes into being. In this paper, I investigate how an under-ice drainage system composed of small, naturally occurring voids can turn into a channel and how this can explain the cyclical behaviour of outburst floods.
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.
Camilo Rada and Christian Schoof
The Cryosphere, 12, 2609–2636, https://doi.org/10.5194/tc-12-2609-2018, https://doi.org/10.5194/tc-12-2609-2018, 2018
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We analyse a large glacier borehole pressure dataset and provide a holistic view of the observations, suggesting a consistent picture of the evolution of the subglacial drainage system. Some aspects are consistent with the established understanding and others ones are not. We propose that most of the inconsistencies arise from the capacity of some areas of the bed to become hydraulically isolated. We present an adaptation of an existing drainage model that incorporates this phenomena.
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Short summary
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.
Water flow across the surface of the Greenland Ice Sheet controls the rate of water flow to the...
