Articles | Volume 18, issue 5
https://doi.org/10.5194/tc-18-2443-2024
© 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-18-2443-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
17 May 2024
Research article |
| 17 May 2024
| 17 May 2024
Geothermal heat source estimations through ice flow modelling at Mýrdalsjökull, Iceland
ThetaFrame Solutions, Kufstein, 6330, Austria
Eyjólfur Magnússon
Institute of Earth Sciences, University of Iceland, Reykjavík, 102, Iceland
Krista Hannesdóttir
Institute of Earth Sciences, University of Iceland, Reykjavík, 102, Iceland
Joaquín M. C. Belart
National Land Survey of Iceland, Akranes, 300, Iceland
Institute of Earth Sciences, University of Iceland, Reykjavík, 102, Iceland
Finnur Pálsson
Institute of Earth Sciences, University of Iceland, Reykjavík, 102, Iceland
Related authors
Alexander H. Jarosch, Paul Hofer, and Christoph Spötl
EGUsphere, https://doi.org/10.5194/egusphere-2024-751, https://doi.org/10.5194/egusphere-2024-751, 2024
Short summary
Short summary
Mechanical damage to stalagmites is commonly observed in mid-latitude caves. In this study we investigate ice flow along the cave bed as a possible mechanism for stalagmite damage. Utilizing models which simulate forces created by ice flow we study the structural integrity of different stalagmite geometries. Our results suggest that structural failure of stalagmites caused by ice flow is possible, albeit unlikely.
Gabriella Koltai, Christoph Spötl, Alexander H. Jarosch, and Hai Cheng
Clim. Past, 17, 775–789, https://doi.org/10.5194/cp-17-775-2021, https://doi.org/10.5194/cp-17-775-2021, 2021
Short summary
Short summary
This paper utilises a novel palaeoclimate archive from caves, cryogenic cave carbonates, which allow for precisely constraining permafrost thawing events in the past. Our study provides new insights into the climate of the Younger Dryas (12 800 to 11 700 years BP) in mid-Europe from the perspective of a high-elevation cave sensitive to permafrost development. We quantify seasonal temperature and precipitation changes by using a heat conduction model.
Anna Wirbel and Alexander Helmut Jarosch
Geosci. Model Dev., 13, 6425–6445, https://doi.org/10.5194/gmd-13-6425-2020, https://doi.org/10.5194/gmd-13-6425-2020, 2020
Short summary
Short summary
We present an open-source numerical tool to simulate the free-surface evolution of gravity-driven flows (e.g. glaciers) constrained by bed topography. No ad hoc post-processing is required to enforce positive ice thickness and mass conservation. We utilise finite elements, define benchmark tests, and showcase glaciological examples. In addition, we provide a thorough analysis of the applicability and robustness of different spatial stabilisation and time discretisation methods.
Fabien Maussion, Anton Butenko, Nicolas Champollion, Matthias Dusch, Julia Eis, Kévin Fourteau, Philipp Gregor, Alexander H. Jarosch, Johannes Landmann, Felix Oesterle, Beatriz Recinos, Timo Rothenpieler, Anouk Vlug, Christian T. Wild, and Ben Marzeion
Geosci. Model Dev., 12, 909–931, https://doi.org/10.5194/gmd-12-909-2019, https://doi.org/10.5194/gmd-12-909-2019, 2019
Short summary
Short summary
Mountain glaciers are one of the few remaining subsystems of the global climate system for which no globally applicable community-driven model exists. Here we present the Open Global Glacier Model (OGGM; www.oggm.org), developed to provide a modular and open-source numerical model framework for simulating past and future change of any glacier in the world.
Giri Gopalan, Birgir Hrafnkelsson, Guðfinna Aðalgeirsdóttir, Alexander H. Jarosch, and Finnur Pálsson
The Cryosphere, 12, 2229–2248, https://doi.org/10.5194/tc-12-2229-2018, https://doi.org/10.5194/tc-12-2229-2018, 2018
Short summary
Short summary
Geophysical systems can often contain scientific parameters whose values are uncertain, complex underlying dynamics, and field measurements with errors. These components are naturally modeled together within what is known as a Bayesian hierarchical model (BHM). This paper constructs such a model for shallow glaciers based on an approximation of the underlying dynamics. The evaluation of this model is aided by the use of exact analytical solutions from the literature.
Anna Wirbel, Alexander H. Jarosch, and Lindsey Nicholson
The Cryosphere, 12, 189–204, https://doi.org/10.5194/tc-12-189-2018, https://doi.org/10.5194/tc-12-189-2018, 2018
Short summary
Short summary
As debris cover affects the meltwater production and behaviour of glaciers it is important to understand how, and over what timescales, it forms. Here we develop an advanced 3-D numerical model that describes transport of sediment through a glacier to the point where it emerges at the surface. The numerical performance of the model is satisfactory and it reproduces debris structures observed within real-world glaciers, thereby offering a useful tool for future studies of debris-covered glaciers.
Joaquín M. C. Belart, Etienne Berthier, Eyjólfur Magnússon, Leif S. Anderson, Finnur Pálsson, Thorsteinn Thorsteinsson, Ian M. Howat, Guðfinna Aðalgeirsdóttir, Tómas Jóhannesson, and Alexander H. Jarosch
The Cryosphere, 11, 1501–1517, https://doi.org/10.5194/tc-11-1501-2017, https://doi.org/10.5194/tc-11-1501-2017, 2017
Short summary
Short summary
Sub-meter satellite stereo images (Pléiades and WorldView2) are used to accurately measure snow accumulation and winter mass balance of Drangajökull ice cap. This is done by creating and comparing accurate digital elevation models. A glacier-wide geodetic mass balance of 3.33 ± 0.23 m w.e. is derived between October 2014 and May 2015. This method could be easily transposable to remote glaciated areas where seasonal mass balance measurements (especially winter accumulation) are lacking.
B. Marzeion, P. W. Leclercq, J. G. Cogley, and A. H. Jarosch
The Cryosphere, 9, 2399–2404, https://doi.org/10.5194/tc-9-2399-2015, https://doi.org/10.5194/tc-9-2399-2015, 2015
Short summary
Short summary
We show that estimates of global glacier mass change during the 20th century, obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist on regional scales.
A. H. Jarosch, C. G. Schoof, and F. S. Anslow
The Cryosphere, 7, 229–240, https://doi.org/10.5194/tc-7-229-2013, https://doi.org/10.5194/tc-7-229-2013, 2013
Alexander H. Jarosch, Paul Hofer, and Christoph Spötl
EGUsphere, https://doi.org/10.5194/egusphere-2024-751, https://doi.org/10.5194/egusphere-2024-751, 2024
Short summary
Short summary
Mechanical damage to stalagmites is commonly observed in mid-latitude caves. In this study we investigate ice flow along the cave bed as a possible mechanism for stalagmite damage. Utilizing models which simulate forces created by ice flow we study the structural integrity of different stalagmite geometries. Our results suggest that structural failure of stalagmites caused by ice flow is possible, albeit unlikely.
Etienne Berthier, Jérôme Lebreton, Delphine Fontannaz, Steven Hosford, Joaquin Munoz Cobo Belart, Fanny Brun, Liss Marie Andreassen, Brian Menounos, and Charlotte Blondel
EGUsphere, https://doi.org/10.5194/egusphere-2024-250, https://doi.org/10.5194/egusphere-2024-250, 2024
Short summary
Short summary
Repeat elevation measurements are crucial for monitoring glacier health and how they affect river flows and sea levels. Until recently, high resolution elevation data were mostly available for polar regions and High Mountain Asia. Our project, the Pléiades Glacier Observatory (PGO), now provides high-resolution topographies of 140 glacier sites worldwide. This is a novel and open dataset to monitor the impact of climate change on glacier at high resolution and accuracy.
Andri Gunnarsson, Sigurdur M. Gardarsson, and Finnur Pálsson
The Cryosphere, 17, 3955–3986, https://doi.org/10.5194/tc-17-3955-2023, https://doi.org/10.5194/tc-17-3955-2023, 2023
Short summary
Short summary
A model was developed with the possibility of utilizing satellite-derived daily surface albedo driven by high-resolution climate data to estimate the surface energy balance (SEB) for all Icelandic glaciers for the period 2000–2021.
Aude Vincent, Clémence Daigre, Ophélie Fischer, Guðfinna Aðalgeirsdóttir, Sophie Violette, Jane Hart, Snævarr Guðmundsson, and Finnur Pálsson
EGUsphere, https://doi.org/10.5194/egusphere-2022-1442, https://doi.org/10.5194/egusphere-2022-1442, 2023
Short summary
Short summary
We studied groundwater near outlet glaciers of the main Icelandic icecap. We acquired new data in the field. Two distinct groundwater compartments and their characteristics are identified. We demonstrate the glacial melt recharge impact on the groundwater dynamic. Knowing groundwater systems in glacial context is crucial to forecast the evolution under climate change of water resources and of potential floods and landslides hazards.
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
Short summary
Short summary
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.
Gabriella Koltai, Christoph Spötl, Alexander H. Jarosch, and Hai Cheng
Clim. Past, 17, 775–789, https://doi.org/10.5194/cp-17-775-2021, https://doi.org/10.5194/cp-17-775-2021, 2021
Short summary
Short summary
This paper utilises a novel palaeoclimate archive from caves, cryogenic cave carbonates, which allow for precisely constraining permafrost thawing events in the past. Our study provides new insights into the climate of the Younger Dryas (12 800 to 11 700 years BP) in mid-Europe from the perspective of a high-elevation cave sensitive to permafrost development. We quantify seasonal temperature and precipitation changes by using a heat conduction model.
Andri Gunnarsson, Sigurdur M. Gardarsson, Finnur Pálsson, Tómas Jóhannesson, and Óli G. B. Sveinsson
The Cryosphere, 15, 547–570, https://doi.org/10.5194/tc-15-547-2021, https://doi.org/10.5194/tc-15-547-2021, 2021
Short summary
Short summary
Surface albedo quantifies the fraction of the sunlight reflected by the surface of the Earth. During the melt season in the Northern Hemisphere solar energy absorbed by snow- and ice-covered surfaces is mainly controlled by surface albedo. For Icelandic glaciers, air temperature and surface albedo are the dominating factors governing annual variability of glacier surface melt. Satellite data from the MODIS sensor are used to create a data set spanning the glacier melt season.
Anna Wirbel and Alexander Helmut Jarosch
Geosci. Model Dev., 13, 6425–6445, https://doi.org/10.5194/gmd-13-6425-2020, https://doi.org/10.5194/gmd-13-6425-2020, 2020
Short summary
Short summary
We present an open-source numerical tool to simulate the free-surface evolution of gravity-driven flows (e.g. glaciers) constrained by bed topography. No ad hoc post-processing is required to enforce positive ice thickness and mass conservation. We utilise finite elements, define benchmark tests, and showcase glaciological examples. In addition, we provide a thorough analysis of the applicability and robustness of different spatial stabilisation and time discretisation methods.
Fabien Maussion, Anton Butenko, Nicolas Champollion, Matthias Dusch, Julia Eis, Kévin Fourteau, Philipp Gregor, Alexander H. Jarosch, Johannes Landmann, Felix Oesterle, Beatriz Recinos, Timo Rothenpieler, Anouk Vlug, Christian T. Wild, and Ben Marzeion
Geosci. Model Dev., 12, 909–931, https://doi.org/10.5194/gmd-12-909-2019, https://doi.org/10.5194/gmd-12-909-2019, 2019
Short summary
Short summary
Mountain glaciers are one of the few remaining subsystems of the global climate system for which no globally applicable community-driven model exists. Here we present the Open Global Glacier Model (OGGM; www.oggm.org), developed to provide a modular and open-source numerical model framework for simulating past and future change of any glacier in the world.
Giri Gopalan, Birgir Hrafnkelsson, Guðfinna Aðalgeirsdóttir, Alexander H. Jarosch, and Finnur Pálsson
The Cryosphere, 12, 2229–2248, https://doi.org/10.5194/tc-12-2229-2018, https://doi.org/10.5194/tc-12-2229-2018, 2018
Short summary
Short summary
Geophysical systems can often contain scientific parameters whose values are uncertain, complex underlying dynamics, and field measurements with errors. These components are naturally modeled together within what is known as a Bayesian hierarchical model (BHM). This paper constructs such a model for shallow glaciers based on an approximation of the underlying dynamics. The evaluation of this model is aided by the use of exact analytical solutions from the literature.
Anna Wirbel, Alexander H. Jarosch, and Lindsey Nicholson
The Cryosphere, 12, 189–204, https://doi.org/10.5194/tc-12-189-2018, https://doi.org/10.5194/tc-12-189-2018, 2018
Short summary
Short summary
As debris cover affects the meltwater production and behaviour of glaciers it is important to understand how, and over what timescales, it forms. Here we develop an advanced 3-D numerical model that describes transport of sediment through a glacier to the point where it emerges at the surface. The numerical performance of the model is satisfactory and it reproduces debris structures observed within real-world glaciers, thereby offering a useful tool for future studies of debris-covered glaciers.
Louise Steffensen Schmidt, Guðfinna Aðalgeirsdóttir, Sverrir Guðmundsson, Peter L. Langen, Finnur Pálsson, Ruth Mottram, Simon Gascoin, and Helgi Björnsson
The Cryosphere, 11, 1665–1684, https://doi.org/10.5194/tc-11-1665-2017, https://doi.org/10.5194/tc-11-1665-2017, 2017
Short summary
Short summary
The regional climate model HIRHAM5 is evaluated over Vatnajökull, Iceland, using automatic weather stations and mass balance observations from 1995 to 2014. From this we asses whether the model can be used to reconstruct the mass balance of the glacier. We find that the simulated energy balance is underestimated overall, but it has been improved by using a new albedo scheme. The specific mass balance is reconstructed back to 1980, thus expanding on the observational records of the mass balance.
Joaquín M. C. Belart, Etienne Berthier, Eyjólfur Magnússon, Leif S. Anderson, Finnur Pálsson, Thorsteinn Thorsteinsson, Ian M. Howat, Guðfinna Aðalgeirsdóttir, Tómas Jóhannesson, and Alexander H. Jarosch
The Cryosphere, 11, 1501–1517, https://doi.org/10.5194/tc-11-1501-2017, https://doi.org/10.5194/tc-11-1501-2017, 2017
Short summary
Short summary
Sub-meter satellite stereo images (Pléiades and WorldView2) are used to accurately measure snow accumulation and winter mass balance of Drangajökull ice cap. This is done by creating and comparing accurate digital elevation models. A glacier-wide geodetic mass balance of 3.33 ± 0.23 m w.e. is derived between October 2014 and May 2015. This method could be easily transposable to remote glaciated areas where seasonal mass balance measurements (especially winter accumulation) are lacking.
Monika Wittmann, Christine Dorothea Groot Zwaaftink, Louise Steffensen Schmidt, Sverrir Guðmundsson, Finnur Pálsson, Olafur Arnalds, Helgi Björnsson, Throstur Thorsteinsson, and Andreas Stohl
The Cryosphere, 11, 741–754, https://doi.org/10.5194/tc-11-741-2017, https://doi.org/10.5194/tc-11-741-2017, 2017
Short summary
Short summary
This work includes a study on the effects of dust deposition on the mass balance of Brúarjökull, an outlet glacier of Vatnajökull, Iceland's largest ice cap. A model was used to simulate dust deposition on the glacier, and these periods of dust were compared to albedo measurements at two weather stations on Brúarjökull to evaluate the dust impact. We determine the influence of dust events on the snow albedo and the surface energy balance.
E. Magnússon, J. Muñoz-Cobo Belart, F. Pálsson, H. Ágústsson, and P. Crochet
The Cryosphere, 10, 159–177, https://doi.org/10.5194/tc-10-159-2016, https://doi.org/10.5194/tc-10-159-2016, 2016
Short summary
Short summary
We demonstrate the opportunities given by high resolution digital elevation models (DEMs) to improve procedures for obtaining mass balance records from archives of aerial photographs. We also describe a geostatistical approach to estimate uncertainty of elevation changes derived by differencing DEMs. This method is more statistically robust than other described in the literature. Our study highlights a common tendency of overestimating this uncertainty, downgrading geodetic mass balance records.
B. Marzeion, P. W. Leclercq, J. G. Cogley, and A. H. Jarosch
The Cryosphere, 9, 2399–2404, https://doi.org/10.5194/tc-9-2399-2015, https://doi.org/10.5194/tc-9-2399-2015, 2015
Short summary
Short summary
We show that estimates of global glacier mass change during the 20th century, obtained from glacier-length-based reconstructions and from a glacier model driven by gridded climate observations are now consistent with each other and also with an estimate for the years 2003-2009 that is mostly based on remotely sensed data. This consistency is found throughout the entire common periods of the respective data sets. Inconsistencies of reconstructions and observations persist on regional scales.
E. Berthier, C. Vincent, E. Magnússon, Á. Þ. Gunnlaugsson, P. Pitte, E. Le Meur, M. Masiokas, L. Ruiz, F. Pálsson, J. M. C. Belart, and P. Wagnon
The Cryosphere, 8, 2275–2291, https://doi.org/10.5194/tc-8-2275-2014, https://doi.org/10.5194/tc-8-2275-2014, 2014
Short summary
Short summary
We evaluate the potential of Pléiades sub-meter satellite stereo imagery to derive digital elevation models (DEMs) of glaciers and their elevation changes. The vertical precision of the DEMs is ±1 m, even ±0.5m on the flat glacier tongues. Similar precision levels are obtained in accumulation areas. Comparison of a Pléiades DEM with a SPOT5 DEM reveals the strongly negative region-wide mass balances of glaciers in the Mont Blanc area (-1.04±0.23m at 1 water equivalent) during 2003-2012.
A. H. Jarosch, C. G. Schoof, and F. S. Anslow
The Cryosphere, 7, 229–240, https://doi.org/10.5194/tc-7-229-2013, https://doi.org/10.5194/tc-7-229-2013, 2013
Related subject area
Discipline: Glaciers | Subject: Subglacial Processes
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
Multi-scale variations of hydro-mechanical conditions at the base of the surge-type glacier Kongsvegen, Svalbard
Channelized, distributed, and disconnected: spatial structure and temporal evolution of the subglacial drainage under a valley glacier in the Yukon
Persistent, extensive channelized drainage modeled beneath Thwaites Glacier, West Antarctica
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
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
Short summary
Short summary
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
Short summary
Short summary
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.
Coline Bouchayer, Ugo Nanni, Pierre-Marie Lefeuvre, John Hulth, Louise Steffensen Schmidt, Jack Kohler, François Renard, and Thomas V. Schuler
EGUsphere, https://doi.org/10.5194/egusphere-2023-618, https://doi.org/10.5194/egusphere-2023-618, 2023
Short summary
Short summary
Glaciers can experience intermittent phases of accelerated movement, called surges, primarily caused by changes occuring beneath the ice, particularly at the ice-bed interface. Studying these subglacial conditions is challenging because of the difficulty of accessing the glacier bed. To overcome this challenge, we monitored changes in the subglacial environment of Kongsvegen Glacier in Svalbard for one year. We discuss our results in the context of glacier destabilization.
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
Short summary
Short summary
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.
Alexander O. Hager, Matthew J. Hoffman, Stephen F. Price, and Dustin M. Schroeder
The Cryosphere, 16, 3575–3599, https://doi.org/10.5194/tc-16-3575-2022, https://doi.org/10.5194/tc-16-3575-2022, 2022
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Cited articles
Belart, J. M. C., Magnússon, E., Berthier, E., Gunnlaugsson, Á. Þ., Pálsson, F., Aðalgeirsdóttir, G., Jóhannesson, T., Thorsteinsson, T., and Björnsson, H.: Mass Balance of 14 Icelandic Glaciers, 1945–2017: Spatial Variations and Links With Climate, Front. Earth Sci., 8, 163, https://doi.org/10.3389/feart.2020.00163, 2020. a, b
Björnsson, H.: Hydrology of ice caps in volcanic regions, University of Iceland, 1988. a
Björnsson, H. and Pálsson, F.: Icelandic glaciers, Jökull, 58, 365–386, 2008. a
Björnsson, H., Pálsson, F., and Guðmundsson, M. T.: Surface and bedrock topography of the Mýrdalsjökull ice cap, Iceland: The Katla caldera, eruption sites and routes of jökulhlaups, Jökull, 49, 29–46, 2000. a
Dziadek, R., Ferraccioli, F., and Gohl, K.: High geothermal heat flow beneath Thwaites Glacier in West Antarctica inferred from aeromagnetic data, Commun. Earth Environ., 2, 162, https://doi.org/10.1038/s43247-021-00242-3, 2021. a
Gagliardini, O., Zwinger, T., Gillet-Chaulet, F., Durand, G., Favier, L., de Fleurian, B., Greve, R., Malinen, M., Martín, C., Råback, P., Ruokolainen, J., Sacchettini, M., Schäfer, M., Seddik, H., and Thies, J.: Capabilities and performance of Elmer/Ice, a new-generation ice sheet model, Geosci. Model Dev., 6, 1299–1318, https://doi.org/10.5194/gmd-6-1299-2013, 2013. a, b
Guðmundsson, M. T. and Högnadóttir, Þ.: Upptök og stærð jökulhlaups í Múlakvísl niðurstöður flugmælinga, Memo, 2011. a
Guðmundsson, M. T., Högnadóttir, Þ., Kristinsson, A. B., and Guðbjörnsson, S.: Geothermal activity in the subglacial Katla caldera, Iceland, 1999–2005, studied with radar altimetry, Ann. Glaciol., 45, 66–72, https://doi.org/10.3189/172756407782282444, 2007. a
Jarosch, A. H. and Gudmundsson, M. T.: Numerical studies of ice flow over subglacial geothermal heat sources at Grímsvötn, Iceland, using Full Stokes equations, J. Geophys. Res., 112, F02008, https://doi.org/10.1029/2006jf000540, 2007. a, b, c
Jarosch, A. H., Magnússon, E., and Belart, J. M. C.: Geothermal heat source estimations through ice flow modelling at Mýrdalsjökull, Iceland – Datasets (1.0), Zenodo [data set], https://doi.org/10.5281/zenodo.11185656, 2024. a
Jóhannesson, T., Björnsson, H., Magnússon, E., Guðmundsson, S., Pálsson, F., Sigurðsson, O., Thorsteinsson, T., and Berthier, E.: Ice-volume changes, bias estimation of mass-balance measurements and changes in subglacial lakes derived by lidar mapping of the surface Icelandic glaciers, Ann. Glaciol., 54, 63–74, https://doi.org/10.3189/2013AoG63A422, 2013. a
Jóhannesson, T., Pálmason, B., Hjartarson, Á., Jarosch, A. H., Magnússon, E., Belart, J. M. C., and Gudmundsson, M. T.: Non-surface mass balance of glaciers in Iceland, J. Glaciol., 66, 685–697, https://doi.org/10.1017/jog.2020.37, 2020. a, b
Kundu, P. K., Cohen, I. M., and Dowling, D. R.: Fluid Mechanics, Elsevier, https://doi.org/10.1016/c2012-0-00611-4, 2016. a
Larsen, G., Guðmundsson, M. T., and Sigmarsson, O.: Náttúruvá á Íslandi, chap. Katla, 211–233, Viðlagatrygging Íslands Háskólaútgáfan, ISBN 978-9979-54-943-7, 2013. a
Magnússon, E., Pálsson, F., Jarosch, A. H., van Boeckel, T., Hannesdóttir, H., and Belart, J. M. C.: The bedrock and tephra layer topography within the glacier filled Katla caldera, Iceland, deduced from dense RES-survey, Jökull, 71, 39–70, https://doi.org/10.33799/jokull2021.71.039, 2021. a, b, c, d, e, f, g, h
Magnússon, E., Pálsson, F., Guðmundsson, M. T., Belart, J. M. C., and Högnadóttir, Þ.: Hvað sýna íssjármælingar undir sigkötlum Mýrdalsjökuls, Tech. rep., Institute of Earth Sciences, University of Iceland, 2017. a
Palmer, S. J., Dowdeswell, J. A., Christoffersen, P., Young, D. A., Blankenship, D. D., Greenbaum, J. S., Benham, T., Bamber, J., and Siegert, M. J.: Greenland subglacial lakes detected by radar, Geophys. Res. Lett., 40, 6154–6159, https://doi.org/10.1002/2013gl058383, 2013. a
Shean, D. E., Alexandrov, O., Moratto, Z. M., Smith, B. E., Joughin, I. R., Porter, C., and Morin, P.: An automated, open-source pipeline for mass production of digital elevation models (DEMs) from very-high-resolution commercial stereo satellite imagery, ISPRS J. Photogramm. Remote, 116, 101–117, https://doi.org/10.1016/j.isprsjprs.2016.03.012, 2016. a, b
Sigurðsson, O., Zóphóníasson, S., and Ísleifsson, E.: Jökulhlaup úr Sólheimajökli 18. júlí 1999, Jökull, 49, 75–80, 2000. a
Smith-Johnsen, S., de Fleurian, B., Schlegel, N., Seroussi, H., and Nisancioglu, K.: Exceptionally high heat flux needed to sustain the Northeast Greenland Ice Stream, The Cryosphere, 14, 841–854, https://doi.org/10.5194/tc-14-841-2020, 2020a. a
Smith-Johnsen, S., Schlegel, N.-J., Fleurian, B., and Nisancioglu, K. H.: Sensitivity of the Northeast Greenland Ice Stream to Geothermal Heat, J. Geophys. Res.-Earth Surf., 125, e2019JF005252, https://doi.org/10.1029/2019jf005252, 2020b. a
Sorey, M. L. and Colvard, E. M.: Measurements of heat and mass flow from thermal areas in Lassen Volcanic National Park, California, 1984-93, Tech. Rep. 94-4180, U.S. Geological Survey, 1994. a
Winsborrow, M. C., Clark, C. D., and Stokes, C. R.: What controls the location of ice streams?, Earth-Sci. Rev., 103, 45–59, https://doi.org/10.1016/j.earscirev.2010.07.003, 2010. a
Wirbel, A. and Jarosch, A. H.: Inequality-constrained free-surface evolution in a full Stokes ice flow model (evolve_glacier v1.1), Geosci. Model Dev., 13, 6425–6445, https://doi.org/10.5194/gmd-13-6425-2020, 2020. a, b
Þórarinsson, S. and Rist, S.: Rannsókn á Kötlu og Kötluhlaupi sumarið 1955, Jökull, 5, 43–46, 1955. a
Short summary
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.
Geothermally active regions beneath glaciers not only influence local ice flow as well as the...
