Articles | Volume 6, issue 6
https://doi.org/10.5194/tc-6-1497-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/tc-6-1497-2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| Highlight paper
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12 Dec 2012
Research article | Highlight paper |
| 12 Dec 2012
The stability of grounding lines on retrograde slopes
G. H. Gudmundsson
British Antarctic Survey, High Cross, Madingley Rd., Cambridge, CB3 0ET, UK
J. Krug
Laboratoire de Glaciologie et Géophysique de l'Environnement, UJF-Grenoble, CNRS, Saint-Martin-d'Hères, France
G. Durand
Laboratoire de Glaciologie et Géophysique de l'Environnement, UJF-Grenoble, CNRS, Saint-Martin-d'Hères, France
L. Favier
Laboratoire de Glaciologie et Géophysique de l'Environnement, UJF-Grenoble, CNRS, Saint-Martin-d'Hères, France
O. Gagliardini
Laboratoire de Glaciologie et Géophysique de l'Environnement, UJF-Grenoble, CNRS, Saint-Martin-d'Hères, France
Institut Universitaire de France, 103, BD Saint-Michel, 75005 Paris, France
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Stephen L. Cornford, Helene Seroussi, Xylar S. Asay-Davis, G. Hilmar Gudmundsson, Rob Arthern, Chris Borstad, Julia Christmann, Thiago Dias dos Santos, Johannes Feldmann, Daniel Goldberg, Matthew J. Hoffman, Angelika Humbert, Thomas Kleiner, Gunter Leguy, William H. Lipscomb, Nacho Merino, Gaël Durand, Mathieu Morlighem, David Pollard, Martin Rückamp, C. Rosie Williams, and Hongju Yu
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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
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Sebastian H. R. Rosier and G. Hilmar Gudmundsson
The Cryosphere, 14, 17–37, https://doi.org/10.5194/tc-14-17-2020, https://doi.org/10.5194/tc-14-17-2020, 2020
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The flow of ice shelves is now known to be strongly affected by ocean tides, but the mechanism by which this happens is unclear. We use a viscoelastic model to try to reproduce observations of this behaviour on the Filchner–Ronne Ice Shelf in Antarctica. We find that tilting of the ice shelf explains the short-period behaviour, while tidally induced movement of the grounding line (the boundary between grounded and floating ice) explains the more complex long-period response.
Jan De Rydt, Gudmundur Hilmar Gudmundsson, Thomas Nagler, and Jan Wuite
The Cryosphere, 13, 2771–2787, https://doi.org/10.5194/tc-13-2771-2019, https://doi.org/10.5194/tc-13-2771-2019, 2019
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Two large icebergs are about to break off from the Brunt Ice Shelf in Antarctica. Rifting started several years ago and is now approaching its final phase. Satellite data and computer simulations show that over the past 2 decades, growth of the ice shelf has caused a build-up of forces within the ice, which culminated in its fracture. These natural changes in geometry coincided with large variations in flow speed, a process that is thought to be relevant for all Antarctic ice shelf margins.
Emily A. Hill, G. Hilmar Gudmundsson, J. Rachel Carr, and Chris R. Stokes
The Cryosphere, 12, 3907–3921, https://doi.org/10.5194/tc-12-3907-2018, https://doi.org/10.5194/tc-12-3907-2018, 2018
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Floating ice tongues in Greenland buttress inland ice, and their removal could accelerate ice flow. Petermann Glacier recently lost large sections of its ice tongue, but there was little glacier acceleration. Here, we assess the impact of future calving events on ice speeds. We find that removing the lower portions of the ice tongue does not accelerate flow. However, future iceberg calving closer to the grounding line could accelerate ice flow and increase ice discharge and sea level rise.
Edward C. King, Jan De Rydt, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3361–3372, https://doi.org/10.5194/tc-12-3361-2018, https://doi.org/10.5194/tc-12-3361-2018, 2018
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Ice shelves are thick sheets of ice floating on the ocean off the coasts of Antarctica and Greenland. They help regulate the flow of ice off the continent. Ice shelves undergo a natural cycle of seaward flow, fracture, iceberg production and regrowth. The Brunt Ice Shelf recently developed two large cracks. We used ground-penetrating radar to find out how the internal structure of the ice might influence the present crack development and the future stability of the ice shelf.
Ronja Reese, Ricarda Winkelmann, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3229–3242, https://doi.org/10.5194/tc-12-3229-2018, https://doi.org/10.5194/tc-12-3229-2018, 2018
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Accurately representing grounding-line flux is essential for modelling the evolution of the Antarctic Ice Sheet. Currently, in some large-scale ice-flow modelling studies a condition on ice flux across grounding lines is imposed using an analytically motivated parameterisation. Here we test this expression for Antarctic grounding lines and find that it provides inaccurate and partly unphysical estimates of ice flux for the highly buttressed ice streams.
Emily A. Hill, J. Rachel Carr, Chris R. Stokes, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3243–3263, https://doi.org/10.5194/tc-12-3243-2018, https://doi.org/10.5194/tc-12-3243-2018, 2018
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The dynamic behaviour (i.e. acceleration and retreat) of outlet glaciers in northern Greenland remains understudied. Here, we provide a new long-term (68-year) record of terminus change. Overall, recent retreat rates (1995–2015) are higher than the last 47 years. Despite region-wide retreat, we found disparities in dynamic behaviour depending on terminus type; grounded glaciers accelerated and thinned following retreat, while glaciers with floating ice tongues were insensitive to recent retreat.
Sebastian H. R. Rosier and G. Hilmar Gudmundsson
The Cryosphere, 12, 1699–1713, https://doi.org/10.5194/tc-12-1699-2018, https://doi.org/10.5194/tc-12-1699-2018, 2018
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Ocean tides cause strong modulation of horizontal ice shelf flow, most notably at a fortnightly frequency that is absent in the vertical tidal forcing. We propose that tidal bending in the margins of the ice shelf produces sufficiently large stresses that the effective viscosity of ice in these regions is reduced during high and low tide. This effect can explain many features of the observed behaviour and implies that ice shelves in areas with strong tides move faster than they otherwise would.
Jan De Rydt, G. Hilmar Gudmundsson, Thomas Nagler, Jan Wuite, and Edward C. King
The Cryosphere, 12, 505–520, https://doi.org/10.5194/tc-12-505-2018, https://doi.org/10.5194/tc-12-505-2018, 2018
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We provide an unprecedented view into the dynamics of two active rifts in the Brunt Ice Shelf through a unique set of field observations, novel satellite data products, and a state-of-the-art ice flow model. We describe the evolution of fracture width and length in great detail, pushing the boundaries of both spatial and temporal coverage, and provide a deeper insight into the process of iceberg formation, which exerts an important control over the mass balance of the Antarctic Ice Sheet.
Werner M. J. Lazeroms, Adrian Jenkins, G. Hilmar Gudmundsson, and Roderik S. W. van de Wal
The Cryosphere, 12, 49–70, https://doi.org/10.5194/tc-12-49-2018, https://doi.org/10.5194/tc-12-49-2018, 2018
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Basal melting of ice shelves is a major factor in the decline of the Antarctic Ice Sheet, which can contribute significantly to sea-level rise. Here, we investigate a new basal melt model based on the dynamics of meltwater plumes. For the first time, this model is applied to all Antarctic ice shelves. The model results in a realistic melt-rate pattern given suitable data for the topography and ocean temperature, making it a promising tool for future simulations of the Antarctic Ice Sheet.
Sebastian H. R. Rosier, G. Hilmar Gudmundsson, Matt A. King, Keith W. Nicholls, Keith Makinson, and Hugh F. J. Corr
Earth Syst. Sci. Data, 9, 849–860, https://doi.org/10.5194/essd-9-849-2017, https://doi.org/10.5194/essd-9-849-2017, 2017
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Tides can affect the flow of ice at hourly to yearly timescales. In some cases the ice responds at a different frequency than is found in the tidal forcing; for example, on Rutford Ice Stream the strongest response is at a fortnightly period. A new compilation of GPS data across the Ronne Ice Shelf and adjoining ice streams shows that this fortnightly modulation in ice flow is found across the entire region. Measurements of this kind can provide insights into ice rheology and basal processes.
Daniel Farinotti, Douglas J. Brinkerhoff, Garry K. C. Clarke, Johannes J. Fürst, Holger Frey, Prateek Gantayat, Fabien Gillet-Chaulet, Claire Girard, Matthias Huss, Paul W. Leclercq, Andreas Linsbauer, Horst Machguth, Carlos Martin, Fabien Maussion, Mathieu Morlighem, Cyrille Mosbeux, Ankur Pandit, Andrea Portmann, Antoine Rabatel, RAAJ Ramsankaran, Thomas J. Reerink, Olivier Sanchez, Peter A. Stentoft, Sangita Singh Kumari, Ward J. J. van Pelt, Brian Anderson, Toby Benham, Daniel Binder, Julian A. Dowdeswell, Andrea Fischer, Kay Helfricht, Stanislav Kutuzov, Ivan Lavrentiev, Robert McNabb, G. Hilmar Gudmundsson, Huilin Li, and Liss M. Andreassen
The Cryosphere, 11, 949–970, https://doi.org/10.5194/tc-11-949-2017, https://doi.org/10.5194/tc-11-949-2017, 2017
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ITMIX – the Ice Thickness Models Intercomparison eXperiment – was the first coordinated performance assessment for models inferring glacier ice thickness from surface characteristics. Considering 17 different models and 21 different test cases, we show that although solutions of individual models can differ considerably, an ensemble average can yield uncertainties in the order of 10 ± 24 % the mean ice thickness. Ways forward for improving such estimates are sketched.
Xylar S. Asay-Davis, Stephen L. Cornford, Gaël Durand, Benjamin K. Galton-Fenzi, Rupert M. Gladstone, G. Hilmar Gudmundsson, Tore Hattermann, David M. Holland, Denise Holland, Paul R. Holland, Daniel F. Martin, Pierre Mathiot, Frank Pattyn, and Hélène Seroussi
Geosci. Model Dev., 9, 2471–2497, https://doi.org/10.5194/gmd-9-2471-2016, https://doi.org/10.5194/gmd-9-2471-2016, 2016
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Coupled ice sheet–ocean models capable of simulating moving grounding lines are just becoming available. Such models have a broad range of potential applications in studying the dynamics of ice sheets and glaciers, including assessing their contributions to sea level change. Here we describe the idealized experiments that make up three interrelated Model Intercomparison Projects (MIPs) for marine ice sheet models and regional ocean circulation models incorporating ice shelf cavities.
David H. Jones, Carl Robinson, and G. Hilmar Gudmundsson
Geosci. Instrum. Method. Data Syst., 5, 65–73, https://doi.org/10.5194/gi-5-65-2016, https://doi.org/10.5194/gi-5-65-2016, 2016
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Long-term records from high-precision GPS receivers are essential for studying geophysical movement. Existing, commercially available, precision GPS receivers are not intended for long-term, autonomous deployment. We have designed a GPS receiver that is better suited for this application. In this paper, we discuss the receiver design and compare its performance with that of some of the commercially available receivers.
S. H. R. Rosier, G. H. Gudmundsson, and J. A. M. Green
The Cryosphere, 9, 1649–1661, https://doi.org/10.5194/tc-9-1649-2015, https://doi.org/10.5194/tc-9-1649-2015, 2015
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We use a full-Stokes model to investigate the long period modulation of Rutford Ice Stream flow by the ocean tide. We find that using a nonlinear sliding law cannot fully explain the measurements and an additional mechanism, whereby tidally induced subglacial pressure variations are transmitted upstream from the grounding line, is also required to match the large amplitude and decay length scale of the observations.
D. H. Jones and G. H. Gudmundsson
Nat. Hazards Earth Syst. Sci., 15, 1243–1250, https://doi.org/10.5194/nhess-15-1243-2015, https://doi.org/10.5194/nhess-15-1243-2015, 2015
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Icebergs are a natural hazard to maritime operations in polar regions. Iceberg populations are increasing, as is the demand for access to both Arctic and Antarctic seas. Soon the ability to reliably track icebergs may become a necessity for continued operational safety. In this paper we describe the design of a tracking sensor that can be deployed from an aircraft during surveys of Antarctic icebergs, and detail the results of its first deployment operation on iceberg B-31.
J. Wuite, H. Rott, M. Hetzenecker, D. Floricioiu, J. De Rydt, G. H. Gudmundsson, T. Nagler, and M. Kern
The Cryosphere, 9, 957–969, https://doi.org/10.5194/tc-9-957-2015, https://doi.org/10.5194/tc-9-957-2015, 2015
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We present new analysis of satellite data showing the variability of glacier velocities in the Larsen B area, Antarctic Peninsula, back to 1995. Velocity data and estimates of ice thickness are used to derive ice discharge at different epochs. Velocities of the glaciers remain to date well above the velocities of the pre-collapse period. The response of individual glaciers differs, and velocities show significant temporal fluctuations, implying major variations in ice discharge and mass balance.
C. Martín, R. Mulvaney, G. H. Gudmundsson, and H. Corr
Clim. Past, 11, 547–557, https://doi.org/10.5194/cp-11-547-2015, https://doi.org/10.5194/cp-11-547-2015, 2015
S. H. R. Rosier, G. H. Gudmundsson, and J. A. M. Green
The Cryosphere, 8, 1763–1775, https://doi.org/10.5194/tc-8-1763-2014, https://doi.org/10.5194/tc-8-1763-2014, 2014
R. Anderson, D. H. Jones, and G. H. Gudmundsson
Nat. Hazards Earth Syst. Sci., 14, 917–927, https://doi.org/10.5194/nhess-14-917-2014, https://doi.org/10.5194/nhess-14-917-2014, 2014
G. H. Gudmundsson
The Cryosphere, 7, 647–655, https://doi.org/10.5194/tc-7-647-2013, https://doi.org/10.5194/tc-7-647-2013, 2013
J. De Rydt, G. H. Gudmundsson, H. F. J. Corr, and P. Christoffersen
The Cryosphere, 7, 407–417, https://doi.org/10.5194/tc-7-407-2013, https://doi.org/10.5194/tc-7-407-2013, 2013
Xianwei Wang, Hilmar Gudmundsson, and David Holland
EGUsphere, https://doi.org/10.5194/egusphere-2024-2790, https://doi.org/10.5194/egusphere-2024-2790, 2024
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Understanding why iceberg calved during drifting in the ocean is important to understand the life cycle and the influence on the surrounding ocean of an iceberg. This study explains why iceberg A68a calved when approaching the South Georgia Island in late 2020 during its drifting in the Southern Ocean using satellite observation and modeling, which was caused by collision with seamount.
Brad Reed, J. A. Mattias Green, Adrian Jenkins, and G. Hilmar Gudmundsson
The Cryosphere, 18, 4567–4587, https://doi.org/10.5194/tc-18-4567-2024, https://doi.org/10.5194/tc-18-4567-2024, 2024
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We use a numerical ice-flow model to simulate the response of a 1940s Pine Island Glacier to changes in melting beneath its ice shelf. A decadal period of warm forcing is sufficient to push the glacier into an unstable, irreversible retreat from its long-term position on a subglacial ridge to an upstream ice plain. This retreat can only be stopped when unrealistic cold forcing is applied. These results show that short warm anomalies can lead to quick and substantial increases in ice flux.
Gong Cheng, Mathieu Morlighem, and G. Hilmar Gudmundsson
Geosci. Model Dev., 17, 6227–6247, https://doi.org/10.5194/gmd-17-6227-2024, https://doi.org/10.5194/gmd-17-6227-2024, 2024
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We conducted a comprehensive analysis of the stabilization and reinitialization techniques currently employed in ISSM and Úa for solving level-set equations, specifically those related to the dynamic representation of moving ice fronts within numerical ice sheet models. Our results demonstrate that the streamline upwind Petrov–Galerkin (SUPG) method outperforms the other approaches. We found that excessively frequent reinitialization can lead to exceptionally high errors in simulations.
Sebastian H. R. Rosier, G. Hilmar Gudmundsson, Adrian Jenkins, and Kaitlin A. Naughten
EGUsphere, https://doi.org/10.5194/egusphere-2024-1838, https://doi.org/10.5194/egusphere-2024-1838, 2024
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Glaciers in the Amundsen Sea region of Antarctica have been retreating and losing mass, but their future contribution to global sea level rise remains highly uncertain. We use an ice sheet model and uncertainty quantification methods to evaluate the probable range of mass loss from this region for two future climate scenarios and find that the rate of ice loss until 2100 will likely remain similar to present-day observations, with little sensitivity to climate scenario over this short timeframe.
Richard Parsons, Sainan Sun, G. Hilmar Gudmundsson, Jan Wuite, and Thomas Nagler
EGUsphere, https://doi.org/10.5194/egusphere-2024-1499, https://doi.org/10.5194/egusphere-2024-1499, 2024
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In 2022, sea ice in Antarctica's Larsen B embayment disintegrated, after which time an increase in the rate at which Crane Glacier discharged ice into the ocean was observed. As the sea ice was attached to the terminus of the glacier, it could provide a resistive stress against the glacier’s ice-flow, slowing down the rate of ice discharge. We used numerical modelling to quantify this resistive stress and found that the sea ice provided significant support to Crane prior to its disintegration.
Juan-Pedro Roldán-Blasco, Adrien Gilbert, Luc Piard, Florent Gimbert, Christian Vincent, Olivier Gagliardini, Anuar Togaibekov, Andrea Walpersdorf, and Nathan Maier
EGUsphere, https://doi.org/10.5194/egusphere-2024-1600, https://doi.org/10.5194/egusphere-2024-1600, 2024
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The flow of glaciers and ice sheets is due to ice deformation and basal sliding driven by gravitational forces. Quantifying the rate at which ice deforms under its own weight is critical to assessing glacier evolution. This study uses borehole instrumentation in an Alpine glacier to quantify ice deformation and constrain its viscosity in a natural setting. Our results show that the viscosity of ice at 0° C is largely influenced by interstitial liquid water which enhances ice deformation.
J. Rachel Carr, Emily A. Hill, and G. Hilmar Gudmundsson
The Cryosphere, 18, 2719–2737, https://doi.org/10.5194/tc-18-2719-2024, https://doi.org/10.5194/tc-18-2719-2024, 2024
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The Greenland Ice Sheet is one of the world's largest glaciers and is melting quickly in response to climate change. It contains fast-flowing channels of ice that move ice from Greenland's centre to its coasts and allow Greenland to react quickly to climate warming. As a result, we want to predict how these glaciers will behave in the future, but there are lots of uncertainties. Here we assess the impacts of two main sources of uncertainties in glacier models.
Cristina Gerli, Sebastian Rosier, G. Hilmar Gudmundsson, and Sainan Sun
The Cryosphere, 18, 2677–2689, https://doi.org/10.5194/tc-18-2677-2024, https://doi.org/10.5194/tc-18-2677-2024, 2024
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Recent efforts have focused on using AI and satellite imagery to track crevasses for assessing ice shelf damage and informing ice flow models. Our study reveals a weak connection between these observed products and damage maps inferred from ice flow models. While there is some improvement in crevasse-dense regions, this association remains limited. Directly mapping ice damage from satellite observations may not significantly improve the representation of these processes within ice flow models.
Ole Richter, Ralph Timmermann, G. Hilmar Gudmundsson, and Jan De Rydt
EGUsphere, https://doi.org/10.5194/egusphere-2024-648, https://doi.org/10.5194/egusphere-2024-648, 2024
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The new coupled ice sheet-ocean model addresses challenges related to horizontal resolution through advanced mesh flexibility, enabled by the use of unstructured grids. We describe the new model, verify its functioning in an idealised setting and demonstrate its advantages in a global-ocean/Antarctic ice sheet domain. The results of this study comprise an important step towards improving predictions of the Antarctic contribution to sea level rise over centennial time scales.
Nicolas C. Jourdain, Charles Amory, Christoph Kittel, and Gaël Durand
EGUsphere, https://doi.org/10.5194/egusphere-2024-58, https://doi.org/10.5194/egusphere-2024-58, 2024
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A mixed statistical-physical approach is used to reproduce the behaviour of a regional climate model. From that, we estimate the contribution of snowfall and melting at the surface of the Antarctic Ice Sheet to changes in global mean sea level. We also investigate the impact of surface melting in a warmer climate on the stability of the Antarctic ice shelves that provide a back stress on the ice flow to the ocean.
Emily A. Hill, Benoît Urruty, Ronja Reese, Julius Garbe, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, Ricarda Winkelmann, Mondher Chekki, David Chandler, and Petra M. Langebroek
The Cryosphere, 17, 3739–3759, https://doi.org/10.5194/tc-17-3739-2023, https://doi.org/10.5194/tc-17-3739-2023, 2023
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The grounding lines of the Antarctic Ice Sheet could enter phases of irreversible retreat or advance. We use three ice sheet models to show that the present-day locations of Antarctic grounding lines are reversible with respect to a small perturbation away from their current position. This indicates that present-day retreat of the grounding lines is not yet irreversible or self-enhancing.
Ronja Reese, Julius Garbe, Emily A. Hill, Benoît Urruty, Kaitlin A. Naughten, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, David Chandler, Petra M. Langebroek, and Ricarda Winkelmann
The Cryosphere, 17, 3761–3783, https://doi.org/10.5194/tc-17-3761-2023, https://doi.org/10.5194/tc-17-3761-2023, 2023
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We use an ice sheet model to test where current climate conditions in Antarctica might lead. We find that present-day ocean and atmosphere conditions might commit an irreversible collapse of parts of West Antarctica which evolves over centuries to millennia. Importantly, this collapse is not irreversible yet.
Sebastian H. R. Rosier, Christopher Y. S. Bull, Wai L. Woo, and G. Hilmar Gudmundsson
The Cryosphere, 17, 499–518, https://doi.org/10.5194/tc-17-499-2023, https://doi.org/10.5194/tc-17-499-2023, 2023
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Future ice loss from Antarctica could raise sea levels by several metres, and key to this is the rate at which the ocean melts the ice sheet from below. Existing methods for modelling this process are either computationally expensive or very simplified. We present a new approach using machine learning to mimic the melt rates calculated by an ocean model but in a fraction of the time. This approach may provide a powerful alternative to existing methods, without compromising on accuracy or speed.
Bertie W. J. Miles, Chris R. Stokes, Adrian Jenkins, Jim R. Jordan, Stewart S. R. Jamieson, and G. Hilmar Gudmundsson
The Cryosphere, 17, 445–456, https://doi.org/10.5194/tc-17-445-2023, https://doi.org/10.5194/tc-17-445-2023, 2023
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Satellite observations have shown that the Shirase Glacier catchment in East Antarctica has been gaining mass over the past 2 decades, a trend largely attributed to increased snowfall. Our multi-decadal observations of Shirase Glacier show that ocean forcing has also contributed to some of this recent mass gain. This has been caused by strengthening easterly winds reducing the inflow of warm water underneath the Shirase ice tongue, causing the glacier to slow down and thicken.
Jeremy Rohmer, Remi Thieblemont, Goneri Le Cozannet, Heiko Goelzer, and Gael Durand
The Cryosphere, 16, 4637–4657, https://doi.org/10.5194/tc-16-4637-2022, https://doi.org/10.5194/tc-16-4637-2022, 2022
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To improve the interpretability of process-based projections of the sea-level contribution from land ice components, we apply the machine-learning-based
SHapley Additive exPlanationsapproach to a subset of a multi-model ensemble study for the Greenland ice sheet. This allows us to quantify the influence of particular modelling decisions (related to numerical implementation, initial conditions, or parametrisation of ice-sheet processes) directly in terms of sea-level change contribution.
Jowan M. Barnes and G. Hilmar Gudmundsson
The Cryosphere, 16, 4291–4304, https://doi.org/10.5194/tc-16-4291-2022, https://doi.org/10.5194/tc-16-4291-2022, 2022
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Models must represent how glaciers slide along the bed, but there are many ways to do so. In this paper, several sliding laws are tested and found to affect different regions of the Antarctic Ice Sheet in different ways and at different speeds. However, the variability in ice volume loss due to sliding-law choices is low compared to other factors, so limited empirical knowledge of sliding does not prevent us from making predictions of how an ice sheet will evolve.
Tom Mitcham, G. Hilmar Gudmundsson, and Jonathan L. Bamber
The Cryosphere, 16, 883–901, https://doi.org/10.5194/tc-16-883-2022, https://doi.org/10.5194/tc-16-883-2022, 2022
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We modelled the response of the Larsen C Ice Shelf (LCIS) and its tributary glaciers to the calving of the A68 iceberg and validated our results with observations. We found that the impact was limited, confirming that mostly passive ice was calved. Through further calving experiments we quantified the total buttressing provided by the LCIS and found that over 80 % of the buttressing capacity is generated in the first 5 km of the ice shelf downstream of the grounding line.
Emily A. Hill, Sebastian H. R. Rosier, G. Hilmar Gudmundsson, and Matthew Collins
The Cryosphere, 15, 4675–4702, https://doi.org/10.5194/tc-15-4675-2021, https://doi.org/10.5194/tc-15-4675-2021, 2021
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Using an ice flow model and uncertainty quantification methods, we provide probabilistic projections of future sea level rise from the Filchner–Ronne region of Antarctica. We find that it is most likely that this region will contribute negatively to sea level rise over the next 300 years, largely as a result of increased surface mass balance. We identify parameters controlling ice shelf melt and snowfall contribute most to uncertainties in projections.
Jowan M. Barnes, Thiago Dias dos Santos, Daniel Goldberg, G. Hilmar Gudmundsson, Mathieu Morlighem, and Jan De Rydt
The Cryosphere, 15, 1975–2000, https://doi.org/10.5194/tc-15-1975-2021, https://doi.org/10.5194/tc-15-1975-2021, 2021
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Some properties of ice flow models must be initialised using observed data before they can be used to produce reliable predictions of the future. Different models have different ways of doing this, and the process is generally seen as being specific to an individual model. We compare the methods used by three different models and show that they produce similar outputs. We also demonstrate that the outputs from one model can be used in other models without introducing large uncertainties.
Sebastian H. R. Rosier, Ronja Reese, Jonathan F. Donges, Jan De Rydt, G. Hilmar Gudmundsson, and Ricarda Winkelmann
The Cryosphere, 15, 1501–1516, https://doi.org/10.5194/tc-15-1501-2021, https://doi.org/10.5194/tc-15-1501-2021, 2021
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Pine Island Glacier has contributed more to sea-level rise over the past decades than any other glacier in Antarctica. Ice-flow modelling studies have shown that it can undergo periods of rapid mass loss, but no study has shown that these future changes could cross a tipping point and therefore be effectively irreversible. Here, we assess the stability of Pine Island Glacier, quantifying the changes in ocean temperatures required to cross future tipping points using statistical methods.
Christian Vincent, Diego Cusicanqui, Bruno Jourdain, Olivier Laarman, Delphine Six, Adrien Gilbert, Andrea Walpersdorf, Antoine Rabatel, Luc Piard, Florent Gimbert, Olivier Gagliardini, Vincent Peyaud, Laurent Arnaud, Emmanuel Thibert, Fanny Brun, and Ugo Nanni
The Cryosphere, 15, 1259–1276, https://doi.org/10.5194/tc-15-1259-2021, https://doi.org/10.5194/tc-15-1259-2021, 2021
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In situ glacier point mass balance data are crucial to assess climate change in different regions of the world. Unfortunately, these data are rare because huge efforts are required to conduct in situ measurements on glaciers. Here, we propose a new approach from remote sensing observations. The method has been tested on the Argentière and Mer de Glace glaciers (France). It should be possible to apply this method to high-spatial-resolution satellite images and on numerous glaciers in the world.
Bertie W. J. Miles, Jim R. Jordan, Chris R. Stokes, Stewart S. R. Jamieson, G. Hilmar Gudmundsson, and Adrian Jenkins
The Cryosphere, 15, 663–676, https://doi.org/10.5194/tc-15-663-2021, https://doi.org/10.5194/tc-15-663-2021, 2021
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We provide a historical overview of changes in Denman Glacier's flow speed, structure and calving events since the 1960s. Based on these observations, we perform a series of numerical modelling experiments to determine the likely cause of Denman's acceleration since the 1970s. We show that grounding line retreat, ice shelf thinning and the detachment of Denman's ice tongue from a pinning point are the most likely causes of the observed acceleration.
Jan De Rydt, Ronja Reese, Fernando S. Paolo, and G. Hilmar Gudmundsson
The Cryosphere, 15, 113–132, https://doi.org/10.5194/tc-15-113-2021, https://doi.org/10.5194/tc-15-113-2021, 2021
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We used satellite observations and numerical simulations of Pine Island Glacier, West Antarctica, between 1996 and 2016 to show that the recent increase in its flow speed can only be reproduced by computer models if stringent assumptions are made about the material properties of the ice and its underlying bed. These assumptions are not commonly adopted in ice flow modelling, and our results therefore have implications for future simulations of Antarctic ice flow and sea level projections.
Kate Winter, Emily A. Hill, G. Hilmar Gudmundsson, and John Woodward
Earth Syst. Sci. Data, 12, 3453–3467, https://doi.org/10.5194/essd-12-3453-2020, https://doi.org/10.5194/essd-12-3453-2020, 2020
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Satellite measurements of the English Coast in the Antarctic Peninsula reveal that glaciers are thinning and losing mass, but ice thickness data are required to assess these changes, in terms of ice flux and sea level contribution. Our ice-penetrating radar measurements reveal that low-elevation subglacial channels control fast-flowing ice streams, which release over 39 Gt of ice per year to floating ice shelves. This topography could make ice flows susceptible to future instability.
Vincent Peyaud, Coline Bouchayer, Olivier Gagliardini, Christian Vincent, Fabien Gillet-Chaulet, Delphine Six, and Olivier Laarman
The Cryosphere, 14, 3979–3994, https://doi.org/10.5194/tc-14-3979-2020, https://doi.org/10.5194/tc-14-3979-2020, 2020
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Alpine glaciers are retreating at an accelerating rate in a warming climate. Numerical models allow us to study and anticipate these changes, but the performance of a model is difficult to evaluate. So we compared an ice flow model with the long dataset of observations obtained between 1979 and 2015 on Mer de Glace (Mont Blanc area). The model accurately reconstructs the past evolution of the glacier. We simulate the future evolution of Mer de Glace; it could retreat by 2 to 6 km by 2050.
Stephen L. Cornford, Helene Seroussi, Xylar S. Asay-Davis, G. Hilmar Gudmundsson, Rob Arthern, Chris Borstad, Julia Christmann, Thiago Dias dos Santos, Johannes Feldmann, Daniel Goldberg, Matthew J. Hoffman, Angelika Humbert, Thomas Kleiner, Gunter Leguy, William H. Lipscomb, Nacho Merino, Gaël Durand, Mathieu Morlighem, David Pollard, Martin Rückamp, C. Rosie Williams, and Hongju Yu
The Cryosphere, 14, 2283–2301, https://doi.org/10.5194/tc-14-2283-2020, https://doi.org/10.5194/tc-14-2283-2020, 2020
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We present the results of the third Marine Ice Sheet Intercomparison Project (MISMIP+). MISMIP+ is one in a series of exercises that test numerical models of ice sheet flow in simple situations. This particular exercise concentrates on the response of ice sheet models to the thinning of their floating ice shelves, which is of interest because numerical models are currently used to model the response to contemporary and near-future thinning in Antarctic ice shelves.
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.
Sebastian H. R. Rosier and G. Hilmar Gudmundsson
The Cryosphere, 14, 17–37, https://doi.org/10.5194/tc-14-17-2020, https://doi.org/10.5194/tc-14-17-2020, 2020
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The flow of ice shelves is now known to be strongly affected by ocean tides, but the mechanism by which this happens is unclear. We use a viscoelastic model to try to reproduce observations of this behaviour on the Filchner–Ronne Ice Shelf in Antarctica. We find that tilting of the ice shelf explains the short-period behaviour, while tidally induced movement of the grounding line (the boundary between grounded and floating ice) explains the more complex long-period response.
Jan De Rydt, Gudmundur Hilmar Gudmundsson, Thomas Nagler, and Jan Wuite
The Cryosphere, 13, 2771–2787, https://doi.org/10.5194/tc-13-2771-2019, https://doi.org/10.5194/tc-13-2771-2019, 2019
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Two large icebergs are about to break off from the Brunt Ice Shelf in Antarctica. Rifting started several years ago and is now approaching its final phase. Satellite data and computer simulations show that over the past 2 decades, growth of the ice shelf has caused a build-up of forces within the ice, which culminated in its fracture. These natural changes in geometry coincided with large variations in flow speed, a process that is thought to be relevant for all Antarctic ice shelf margins.
Lionel Favier, Nicolas C. Jourdain, Adrian Jenkins, Nacho Merino, Gaël Durand, Olivier Gagliardini, Fabien Gillet-Chaulet, and Pierre Mathiot
Geosci. Model Dev., 12, 2255–2283, https://doi.org/10.5194/gmd-12-2255-2019, https://doi.org/10.5194/gmd-12-2255-2019, 2019
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The melting at the base of floating ice shelves is the main driver of the Antarctic ice sheet current retreat. Here, we use an ideal set-up to assess a wide range of melting parameterisations depending on oceanic properties with regard to a new ocean–ice-sheet coupled model, published here for the first time. A parameterisation that depends quadratically on thermal forcing in both a local and a non-local way yields the best results and needs to be further assessed with more realistic set-ups.
Julien Brondex, Fabien Gillet-Chaulet, and Olivier Gagliardini
The Cryosphere, 13, 177–195, https://doi.org/10.5194/tc-13-177-2019, https://doi.org/10.5194/tc-13-177-2019, 2019
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Here, we apply a synthetic perturbation to the most active drainage basin of Antarctica and show that centennial mass loss projections obtained through ice flow models depend strongly on the implemented friction law, i.e. the mathematical relationship between basal drag and sliding velocities. In particular, the commonly used Weertman law considerably underestimates the sea-level contribution of this basin in comparison to two water pressure-dependent laws which rely on stronger physical bases.
Emily A. Hill, G. Hilmar Gudmundsson, J. Rachel Carr, and Chris R. Stokes
The Cryosphere, 12, 3907–3921, https://doi.org/10.5194/tc-12-3907-2018, https://doi.org/10.5194/tc-12-3907-2018, 2018
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Floating ice tongues in Greenland buttress inland ice, and their removal could accelerate ice flow. Petermann Glacier recently lost large sections of its ice tongue, but there was little glacier acceleration. Here, we assess the impact of future calving events on ice speeds. We find that removing the lower portions of the ice tongue does not accelerate flow. However, future iceberg calving closer to the grounding line could accelerate ice flow and increase ice discharge and sea level rise.
Edward C. King, Jan De Rydt, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3361–3372, https://doi.org/10.5194/tc-12-3361-2018, https://doi.org/10.5194/tc-12-3361-2018, 2018
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Ice shelves are thick sheets of ice floating on the ocean off the coasts of Antarctica and Greenland. They help regulate the flow of ice off the continent. Ice shelves undergo a natural cycle of seaward flow, fracture, iceberg production and regrowth. The Brunt Ice Shelf recently developed two large cracks. We used ground-penetrating radar to find out how the internal structure of the ice might influence the present crack development and the future stability of the ice shelf.
Ronja Reese, Ricarda Winkelmann, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3229–3242, https://doi.org/10.5194/tc-12-3229-2018, https://doi.org/10.5194/tc-12-3229-2018, 2018
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Accurately representing grounding-line flux is essential for modelling the evolution of the Antarctic Ice Sheet. Currently, in some large-scale ice-flow modelling studies a condition on ice flux across grounding lines is imposed using an analytically motivated parameterisation. Here we test this expression for Antarctic grounding lines and find that it provides inaccurate and partly unphysical estimates of ice flux for the highly buttressed ice streams.
Emily A. Hill, J. Rachel Carr, Chris R. Stokes, and G. Hilmar Gudmundsson
The Cryosphere, 12, 3243–3263, https://doi.org/10.5194/tc-12-3243-2018, https://doi.org/10.5194/tc-12-3243-2018, 2018
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The dynamic behaviour (i.e. acceleration and retreat) of outlet glaciers in northern Greenland remains understudied. Here, we provide a new long-term (68-year) record of terminus change. Overall, recent retreat rates (1995–2015) are higher than the last 47 years. Despite region-wide retreat, we found disparities in dynamic behaviour depending on terminus type; grounded glaciers accelerated and thinned following retreat, while glaciers with floating ice tongues were insensitive to recent retreat.
Marianne Haseloff, Christian Schoof, and Olivier Gagliardini
The Cryosphere, 12, 2545–2568, https://doi.org/10.5194/tc-12-2545-2018, https://doi.org/10.5194/tc-12-2545-2018, 2018
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The widths of the Siple Coast ice streams evolve on decadal to centennial timescales. We investigate how the rate of thermally driven ice stream widening depends on heat dissipation in the ice stream margin and at the bed, and on the inflow of cold ice from the ice ridge. As determining the migration rate requires resolving heat transfer processes on very small scales, we derive a parametrization of the migration rate in terms of parameters that are available from large-scale model outputs.
Olivier Passalacqua, Marie Cavitte, Olivier Gagliardini, Fabien Gillet-Chaulet, Frédéric Parrenin, Catherine Ritz, and Duncan Young
The Cryosphere, 12, 2167–2174, https://doi.org/10.5194/tc-12-2167-2018, https://doi.org/10.5194/tc-12-2167-2018, 2018
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Locating a suitable drill site is a key step in the Antarctic oldest-ice challenge. Here we have conducted a 3-D ice flow simulation in the region of Dome C using a refined bedrock description. Five selection criteria are computed that together provide an objective overview on the local ice flow conditions. We delineate kilometer-scale favorable areas that overlap with the ones recently proposed by another group. We propose a few drill sites that should be surveyed during the next field seasons.
Sebastian H. R. Rosier and G. Hilmar Gudmundsson
The Cryosphere, 12, 1699–1713, https://doi.org/10.5194/tc-12-1699-2018, https://doi.org/10.5194/tc-12-1699-2018, 2018
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Ocean tides cause strong modulation of horizontal ice shelf flow, most notably at a fortnightly frequency that is absent in the vertical tidal forcing. We propose that tidal bending in the margins of the ice shelf produces sufficiently large stresses that the effective viscosity of ice in these regions is reduced during high and low tide. This effect can explain many features of the observed behaviour and implies that ice shelves in areas with strong tides move faster than they otherwise would.
Heiko Goelzer, Sophie Nowicki, Tamsin Edwards, Matthew Beckley, Ayako Abe-Ouchi, Andy Aschwanden, Reinhard Calov, Olivier Gagliardini, Fabien Gillet-Chaulet, Nicholas R. Golledge, Jonathan Gregory, Ralf Greve, Angelika Humbert, Philippe Huybrechts, Joseph H. Kennedy, Eric Larour, William H. Lipscomb, Sébastien Le clec'h, Victoria Lee, Mathieu Morlighem, Frank Pattyn, Antony J. Payne, Christian Rodehacke, Martin Rückamp, Fuyuki Saito, Nicole Schlegel, Helene Seroussi, Andrew Shepherd, Sainan Sun, Roderik van de Wal, and Florian A. Ziemen
The Cryosphere, 12, 1433–1460, https://doi.org/10.5194/tc-12-1433-2018, https://doi.org/10.5194/tc-12-1433-2018, 2018
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We have compared a wide spectrum of different initialisation techniques used in the ice sheet modelling community to define the modelled present-day Greenland ice sheet state as a starting point for physically based future-sea-level-change projections. Compared to earlier community-wide comparisons, we find better agreement across different models, which implies overall improvement of our understanding of what is needed to produce such initial states.
Jan De Rydt, G. Hilmar Gudmundsson, Thomas Nagler, Jan Wuite, and Edward C. King
The Cryosphere, 12, 505–520, https://doi.org/10.5194/tc-12-505-2018, https://doi.org/10.5194/tc-12-505-2018, 2018
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We provide an unprecedented view into the dynamics of two active rifts in the Brunt Ice Shelf through a unique set of field observations, novel satellite data products, and a state-of-the-art ice flow model. We describe the evolution of fracture width and length in great detail, pushing the boundaries of both spatial and temporal coverage, and provide a deeper insight into the process of iceberg formation, which exerts an important control over the mass balance of the Antarctic Ice Sheet.
Werner M. J. Lazeroms, Adrian Jenkins, G. Hilmar Gudmundsson, and Roderik S. W. van de Wal
The Cryosphere, 12, 49–70, https://doi.org/10.5194/tc-12-49-2018, https://doi.org/10.5194/tc-12-49-2018, 2018
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Basal melting of ice shelves is a major factor in the decline of the Antarctic Ice Sheet, which can contribute significantly to sea-level rise. Here, we investigate a new basal melt model based on the dynamics of meltwater plumes. For the first time, this model is applied to all Antarctic ice shelves. The model results in a realistic melt-rate pattern given suitable data for the topography and ocean temperature, making it a promising tool for future simulations of the Antarctic Ice Sheet.
Sebastian H. R. Rosier, G. Hilmar Gudmundsson, Matt A. King, Keith W. Nicholls, Keith Makinson, and Hugh F. J. Corr
Earth Syst. Sci. Data, 9, 849–860, https://doi.org/10.5194/essd-9-849-2017, https://doi.org/10.5194/essd-9-849-2017, 2017
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Tides can affect the flow of ice at hourly to yearly timescales. In some cases the ice responds at a different frequency than is found in the tidal forcing; for example, on Rutford Ice Stream the strongest response is at a fortnightly period. A new compilation of GPS data across the Ronne Ice Shelf and adjoining ice streams shows that this fortnightly modulation in ice flow is found across the entire region. Measurements of this kind can provide insights into ice rheology and basal processes.
Frédéric Parrenin, Marie G. P. Cavitte, Donald D. Blankenship, Jérôme Chappellaz, Hubertus Fischer, Olivier Gagliardini, Valérie Masson-Delmotte, Olivier Passalacqua, Catherine Ritz, Jason Roberts, Martin J. Siegert, and Duncan A. Young
The Cryosphere, 11, 2427–2437, https://doi.org/10.5194/tc-11-2427-2017, https://doi.org/10.5194/tc-11-2427-2017, 2017
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The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC), reaching ~ 800 000 years. Obtaining an older palaeoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we estimate the age of basal ice in the Dome C area. We find that old ice (> 1.5 Myr) likely exists in two regions a few tens of kilometres away from EDC:
Little Dome C Patchand
North Patch.
Daniel Farinotti, Douglas J. Brinkerhoff, Garry K. C. Clarke, Johannes J. Fürst, Holger Frey, Prateek Gantayat, Fabien Gillet-Chaulet, Claire Girard, Matthias Huss, Paul W. Leclercq, Andreas Linsbauer, Horst Machguth, Carlos Martin, Fabien Maussion, Mathieu Morlighem, Cyrille Mosbeux, Ankur Pandit, Andrea Portmann, Antoine Rabatel, RAAJ Ramsankaran, Thomas J. Reerink, Olivier Sanchez, Peter A. Stentoft, Sangita Singh Kumari, Ward J. J. van Pelt, Brian Anderson, Toby Benham, Daniel Binder, Julian A. Dowdeswell, Andrea Fischer, Kay Helfricht, Stanislav Kutuzov, Ivan Lavrentiev, Robert McNabb, G. Hilmar Gudmundsson, Huilin Li, and Liss M. Andreassen
The Cryosphere, 11, 949–970, https://doi.org/10.5194/tc-11-949-2017, https://doi.org/10.5194/tc-11-949-2017, 2017
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ITMIX – the Ice Thickness Models Intercomparison eXperiment – was the first coordinated performance assessment for models inferring glacier ice thickness from surface characteristics. Considering 17 different models and 21 different test cases, we show that although solutions of individual models can differ considerably, an ensemble average can yield uncertainties in the order of 10 ± 24 % the mean ice thickness. Ways forward for improving such estimates are sketched.
Rupert Michael Gladstone, Roland Charles Warner, Benjamin Keith Galton-Fenzi, Olivier Gagliardini, Thomas Zwinger, and Ralf Greve
The Cryosphere, 11, 319–329, https://doi.org/10.5194/tc-11-319-2017, https://doi.org/10.5194/tc-11-319-2017, 2017
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Computer models are used to simulate the behaviour of glaciers and ice sheets. It has been found that such models are required to be run at very high resolution (which means high computational expense) in order to accurately represent the evolution of marine ice sheets (ice sheets resting on bedrock below sea level), in certain situations which depend on sub-glacial physical processes.
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.
Xylar S. Asay-Davis, Stephen L. Cornford, Gaël Durand, Benjamin K. Galton-Fenzi, Rupert M. Gladstone, G. Hilmar Gudmundsson, Tore Hattermann, David M. Holland, Denise Holland, Paul R. Holland, Daniel F. Martin, Pierre Mathiot, Frank Pattyn, and Hélène Seroussi
Geosci. Model Dev., 9, 2471–2497, https://doi.org/10.5194/gmd-9-2471-2016, https://doi.org/10.5194/gmd-9-2471-2016, 2016
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Coupled ice sheet–ocean models capable of simulating moving grounding lines are just becoming available. Such models have a broad range of potential applications in studying the dynamics of ice sheets and glaciers, including assessing their contributions to sea level change. Here we describe the idealized experiments that make up three interrelated Model Intercomparison Projects (MIPs) for marine ice sheet models and regional ocean circulation models incorporating ice shelf cavities.
Olivier Passalacqua, Olivier Gagliardini, Frédéric Parrenin, Joe Todd, Fabien Gillet-Chaulet, and Catherine Ritz
Geosci. Model Dev., 9, 2301–2313, https://doi.org/10.5194/gmd-9-2301-2016, https://doi.org/10.5194/gmd-9-2301-2016, 2016
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In ice-flow modelling, computing in 3-D requires a lot of resources, but 2-D models lack physical likelihood when the flow is diverging. That is why 2-D models accounting for the divergence, so-called 2.5-D models, are an interesting trade-off. However, the applicability of these 2.5-D models has never been systematically examined. We show that these models are ineffective in the case of highly diverging flows, but also for varying temperature, which was not suspected.
David H. Jones, Carl Robinson, and G. Hilmar Gudmundsson
Geosci. Instrum. Method. Data Syst., 5, 65–73, https://doi.org/10.5194/gi-5-65-2016, https://doi.org/10.5194/gi-5-65-2016, 2016
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Long-term records from high-precision GPS receivers are essential for studying geophysical movement. Existing, commercially available, precision GPS receivers are not intended for long-term, autonomous deployment. We have designed a GPS receiver that is better suited for this application. In this paper, we discuss the receiver design and compare its performance with that of some of the commercially available receivers.
O. Gagliardini, J. Brondex, F. Gillet-Chaulet, L. Tavard, V. Peyaud, and G. Durand
The Cryosphere, 10, 307–312, https://doi.org/10.5194/tc-10-307-2016, https://doi.org/10.5194/tc-10-307-2016, 2016
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In this paper it is shown that the sensitivity to the mesh resolution is not
improved for a vanishing friction at the grounding line (GL). For a discontinuous friction at the GL, we further show that the results are moreover very sensitive to the way the friction is interpolated in the close vicinity of the GL. In the light of these new insights, new results for the MISMIP3d experiments obtained for higher resolutions than previously published are made available for future comparisons.
G. Durand and F. Pattyn
The Cryosphere, 9, 2043–2055, https://doi.org/10.5194/tc-9-2043-2015, https://doi.org/10.5194/tc-9-2043-2015, 2015
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Projections of Antarctic dynamics and contribution to sea-level rise are evaluated in the light of intercomparison exercises dedicated to evaluate models' ability of representing coastal changes. Uncertainties in projections can be substantially decreased if a selection of models is made and models that are unqualified for the representation of coastal dynamics are excluded.
S. H. R. Rosier, G. H. Gudmundsson, and J. A. M. Green
The Cryosphere, 9, 1649–1661, https://doi.org/10.5194/tc-9-1649-2015, https://doi.org/10.5194/tc-9-1649-2015, 2015
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We use a full-Stokes model to investigate the long period modulation of Rutford Ice Stream flow by the ocean tide. We find that using a nonlinear sliding law cannot fully explain the measurements and an additional mechanism, whereby tidally induced subglacial pressure variations are transmitted upstream from the grounding line, is also required to match the large amplitude and decay length scale of the observations.
J.-L. Tison, M. de Angelis, G. Littot, E. Wolff, H. Fischer, M. Hansson, M. Bigler, R. Udisti, A. Wegner, J. Jouzel, B. Stenni, S. Johnsen, V. Masson-Delmotte, A. Landais, V. Lipenkov, L. Loulergue, J.-M. Barnola, J.-R. Petit, B. Delmonte, G. Dreyfus, D. Dahl-Jensen, G. Durand, B. Bereiter, A. Schilt, R. Spahni, K. Pol, R. Lorrain, R. Souchez, and D. Samyn
The Cryosphere, 9, 1633–1648, https://doi.org/10.5194/tc-9-1633-2015, https://doi.org/10.5194/tc-9-1633-2015, 2015
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The oldest paleoclimatic information is buried within the lowermost layers of deep ice cores. It is therefore essential to judge how deep these records remain unaltered. We study the bottom 60 meters of the EPICA Dome C ice core from central Antarctica to show that the paleoclimatic signal is only affected at the small scale (decimeters) in terms of some of the global ice properties. However our data suggest that the time scale has been considerably distorted by mechanical stretching.
J. J. Fürst, G. Durand, F. Gillet-Chaulet, N. Merino, L. Tavard, J. Mouginot, N. Gourmelen, and O. Gagliardini
The Cryosphere, 9, 1427–1443, https://doi.org/10.5194/tc-9-1427-2015, https://doi.org/10.5194/tc-9-1427-2015, 2015
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We present a comprehensive high-resolution assimilation of Antarctic surface velocities with a flow model. The inferred velocities are in very good agreement with observations, even when compared to recent studies on individual shelves. This quality allows to identify a pattern in the velocity mismatch that points at pinning points not present in the input geometry. We identify seven potential pinning points around Antarctica, for now uncharted, providing prominent resistance to the ice flow.
D. H. Jones and G. H. Gudmundsson
Nat. Hazards Earth Syst. Sci., 15, 1243–1250, https://doi.org/10.5194/nhess-15-1243-2015, https://doi.org/10.5194/nhess-15-1243-2015, 2015
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Icebergs are a natural hazard to maritime operations in polar regions. Iceberg populations are increasing, as is the demand for access to both Arctic and Antarctic seas. Soon the ability to reliably track icebergs may become a necessity for continued operational safety. In this paper we describe the design of a tracking sensor that can be deployed from an aircraft during surveys of Antarctic icebergs, and detail the results of its first deployment operation on iceberg B-31.
J. Krug, G. Durand, O. Gagliardini, and J. Weiss
The Cryosphere, 9, 989–1003, https://doi.org/10.5194/tc-9-989-2015, https://doi.org/10.5194/tc-9-989-2015, 2015
J. Wuite, H. Rott, M. Hetzenecker, D. Floricioiu, J. De Rydt, G. H. Gudmundsson, T. Nagler, and M. Kern
The Cryosphere, 9, 957–969, https://doi.org/10.5194/tc-9-957-2015, https://doi.org/10.5194/tc-9-957-2015, 2015
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We present new analysis of satellite data showing the variability of glacier velocities in the Larsen B area, Antarctic Peninsula, back to 1995. Velocity data and estimates of ice thickness are used to derive ice discharge at different epochs. Velocities of the glaciers remain to date well above the velocities of the pre-collapse period. The response of individual glaciers differs, and velocities show significant temporal fluctuations, implying major variations in ice discharge and mass balance.
C. Martín, R. Mulvaney, G. H. Gudmundsson, and H. Corr
Clim. Past, 11, 547–557, https://doi.org/10.5194/cp-11-547-2015, https://doi.org/10.5194/cp-11-547-2015, 2015
J. Krug, J. Weiss, O. Gagliardini, and G. Durand
The Cryosphere, 8, 2101–2117, https://doi.org/10.5194/tc-8-2101-2014, https://doi.org/10.5194/tc-8-2101-2014, 2014
S. H. R. Rosier, G. H. Gudmundsson, and J. A. M. Green
The Cryosphere, 8, 1763–1775, https://doi.org/10.5194/tc-8-1763-2014, https://doi.org/10.5194/tc-8-1763-2014, 2014
E. Le Meur, M. Sacchettini, S. Garambois, E. Berthier, A. S. Drouet, G. Durand, D. Young, J. S. Greenbaum, J. W. Holt, D. D. Blankenship, E. Rignot, J. Mouginot, Y. Gim, D. Kirchner, B. de Fleurian, O. Gagliardini, and F. Gillet-Chaulet
The Cryosphere, 8, 1331–1346, https://doi.org/10.5194/tc-8-1331-2014, https://doi.org/10.5194/tc-8-1331-2014, 2014
R. Anderson, D. H. Jones, and G. H. Gudmundsson
Nat. Hazards Earth Syst. Sci., 14, 917–927, https://doi.org/10.5194/nhess-14-917-2014, https://doi.org/10.5194/nhess-14-917-2014, 2014
J. Krug, J. Weiss, O. Gagliardini, and G. Durand
The Cryosphere Discuss., https://doi.org/10.5194/tcd-8-1111-2014, https://doi.org/10.5194/tcd-8-1111-2014, 2014
Preprint withdrawn
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
A. Legchenko, C. Vincent, J. M. Baltassat, J. F. Girard, E. Thibert, O. Gagliardini, M. Descloitres, A. Gilbert, S. Garambois, A. Chevalier, and H. Guyard
The Cryosphere, 8, 155–166, https://doi.org/10.5194/tc-8-155-2014, https://doi.org/10.5194/tc-8-155-2014, 2014
B. de Fleurian, O. Gagliardini, T. Zwinger, G. Durand, E. Le Meur, D. Mair, and P. Råback
The Cryosphere, 8, 137–153, https://doi.org/10.5194/tc-8-137-2014, https://doi.org/10.5194/tc-8-137-2014, 2014
O. Gagliardini, T. Zwinger, F. Gillet-Chaulet, G. Durand, L. Favier, B. de Fleurian, R. Greve, M. Malinen, C. Martín, P. Råback, J. Ruokolainen, M. Sacchettini, M. Schäfer, H. Seddik, and J. Thies
Geosci. Model Dev., 6, 1299–1318, https://doi.org/10.5194/gmd-6-1299-2013, https://doi.org/10.5194/gmd-6-1299-2013, 2013
G. H. Gudmundsson
The Cryosphere, 7, 647–655, https://doi.org/10.5194/tc-7-647-2013, https://doi.org/10.5194/tc-7-647-2013, 2013
V. Favier, C. Agosta, S. Parouty, G. Durand, G. Delaygue, H. Gallée, A.-S. Drouet, A. Trouvilliez, and G. Krinner
The Cryosphere, 7, 583–597, https://doi.org/10.5194/tc-7-583-2013, https://doi.org/10.5194/tc-7-583-2013, 2013
A. S. Drouet, D. Docquier, G. Durand, R. Hindmarsh, F. Pattyn, O. Gagliardini, and T. Zwinger
The Cryosphere, 7, 395–406, https://doi.org/10.5194/tc-7-395-2013, https://doi.org/10.5194/tc-7-395-2013, 2013
J. De Rydt, G. H. Gudmundsson, H. F. J. Corr, and P. Christoffersen
The Cryosphere, 7, 407–417, https://doi.org/10.5194/tc-7-407-2013, https://doi.org/10.5194/tc-7-407-2013, 2013
F. Gillet-Chaulet, O. Gagliardini, H. Seddik, M. Nodet, G. Durand, C. Ritz, T. Zwinger, R. Greve, and D. G. Vaughan
The Cryosphere, 6, 1561–1576, https://doi.org/10.5194/tc-6-1561-2012, https://doi.org/10.5194/tc-6-1561-2012, 2012
Related subject area
Numerical Modelling
Two-way coupling between ice flow and channelized subglacial drainage enhances modeled marine-ice-sheet retreat
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Application of a regularised Coulomb sliding law to Jakobshavn Isbræ, western Greenland
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George Lu and Jonathan Kingslake
The Cryosphere, 18, 5301–5321, https://doi.org/10.5194/tc-18-5301-2024, https://doi.org/10.5194/tc-18-5301-2024, 2024
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Water below ice sheets affects ice-sheet motion, while the evolution of ice sheets likewise affects the water below. We create a model that allows for water and ice to affect each other and use it to see how this coupling or lack thereof may impact ice-sheet retreat. We find that coupling an evolving water system with the ice sheet results in more retreat than if we assume unchanging conditions under the ice, which indicates a need to better represent the effects of water in ice-sheet models.
Yu Wang, Chen Zhao, Rupert Gladstone, Thomas Zwinger, Benjamin K. Galton-Fenzi, and Poul Christoffersen
The Cryosphere, 18, 5117–5137, https://doi.org/10.5194/tc-18-5117-2024, https://doi.org/10.5194/tc-18-5117-2024, 2024
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Our research delves into the future evolution of Antarctica's Wilkes Subglacial Basin (WSB) and its potential contribution to sea level rise, focusing on how basal melt is implemented at the grounding line in ice flow models. Our findings suggest that these implementation methods can significantly impact the magnitude of future ice loss projections. Under a high-emission scenario, the WSB ice sheet could undergo massive and rapid retreat between 2200 and 2300.
Sylvie Charbit, Christophe Dumas, Fabienne Maignan, Catherine Ottlé, Nina Raoult, Xavier Fettweis, and Philippe Conesa
The Cryosphere, 18, 5067–5099, https://doi.org/10.5194/tc-18-5067-2024, https://doi.org/10.5194/tc-18-5067-2024, 2024
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The evolution of the Greenland ice sheet is highly dependent on surface melting and therefore on the processes operating at the snow–atmosphere interface and within the snow cover. Here we present new developments to apply a snow model to the Greenland ice sheet. The performance of this model is analysed in terms of its ability to simulate ablation processes. Our analysis shows that the model performs well when compared with the MAR regional polar atmospheric model.
Matt Trevers, Antony J. Payne, and Stephen L. Cornford
The Cryosphere, 18, 5101–5115, https://doi.org/10.5194/tc-18-5101-2024, https://doi.org/10.5194/tc-18-5101-2024, 2024
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The form of the friction law which determines the speed of ice sliding over the bedrock remains a major source of uncertainty in ice sheet model projections of future sea level rise. Jakobshavn Isbræ, the fastest-flowing glacier in Greenland, which has undergone significant changes in the last few decades, is an ideal case for testing sliding laws. We find that a regularised Coulomb friction law reproduces the large seasonal and inter-annual flow speed variations most accurately.
Alexander H. Jarosch, Paul Hofer, and Christoph Spötl
The Cryosphere, 18, 4811–4816, https://doi.org/10.5194/tc-18-4811-2024, https://doi.org/10.5194/tc-18-4811-2024, 2024
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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.
Cecile B. Menard, Sirpa Rasmus, Ioanna Merkouriadi, Gianpaolo Balsamo, Annett Bartsch, Chris Derksen, Florent Domine, Marie Dumont, Dorothee Ehrich, Richard Essery, Bruce C. Forbes, Gerhard Krinner, David Lawrence, Glen Liston, Heidrun Matthes, Nick Rutter, Melody Sandells, Martin Schneebeli, and Sari Stark
The Cryosphere, 18, 4671–4686, https://doi.org/10.5194/tc-18-4671-2024, https://doi.org/10.5194/tc-18-4671-2024, 2024
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Computer models, like those used in climate change studies, are written by modellers who have to decide how best to construct the models in order to satisfy the purpose they serve. Using snow modelling as an example, we examine the process behind the decisions to understand what motivates or limits modellers in their decision-making. We find that the context in which research is undertaken is often more crucial than scientific limitations. We argue for more transparency in our research practice.
Giulia Mazzotti, Jari-Pekka Nousu, Vincent Vionnet, Tobias Jonas, Rafife Nheili, and Matthieu Lafaysse
The Cryosphere, 18, 4607–4632, https://doi.org/10.5194/tc-18-4607-2024, https://doi.org/10.5194/tc-18-4607-2024, 2024
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As many boreal and alpine forests have seasonal snow, models are needed to predict forest snow under future environmental conditions. We have created a new forest snow model by combining existing, very detailed model components for the canopy and the snowpack. We applied it to forests in Switzerland and Finland and showed how complex forest cover leads to a snowpack layering that is very variable in space and time because different processes prevail at different locations in the forest.
Xu Zhou, Binbin Wang, Xiaogang Ma, Zhu La, and Kun Yang
The Cryosphere, 18, 4589–4605, https://doi.org/10.5194/tc-18-4589-2024, https://doi.org/10.5194/tc-18-4589-2024, 2024
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The simulation of the ice phenology of Nam Co by WRF is investigated. Compared with the default model, improving the key lake schemes, such as water surface roughness length for heat fluxes and the shortwave radiation transfer for lake ice, can better simulate the lake ice phenology. The still existing errors in the spatial patterns of lake ice phenology imply that challenges still exist in modelling key lake and non-lake physics such as grid-scale water circulation and snow-related processes.
Amir Sedaghatkish, Frédéric Doumenc, Pierre-Yves Jeannin, and Marc Luetscher
The Cryosphere, 18, 4531–4546, https://doi.org/10.5194/tc-18-4531-2024, https://doi.org/10.5194/tc-18-4531-2024, 2024
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We developed a model to simulate the natural convection of water within frozen rock crevices subject to daily warming in mountain permafrost regions. Traditional models relying on conduction and latent heat flux typically overlook free convection. The results reveal that free convection can significantly accelerate the melting rate by an order of magnitude compared to conduction-based models. Our results are important for assessing the impact of climate change on mountain infrastructure.
Joseph Fogarty, Elie Bou-Zeid, Mitchell Bushuk, and Linette Boisvert
The Cryosphere, 18, 4335–4354, https://doi.org/10.5194/tc-18-4335-2024, https://doi.org/10.5194/tc-18-4335-2024, 2024
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We hypothesize that using a broad set of surface characterization metrics for polar sea ice surfaces will lead to more accurate representations in general circulation models. However, the first step is to identify the minimum set of metrics required. We show via numerical simulations that sea ice surface patterns can play a crucial role in determining boundary layer structures. We then statistically analyze a set of high-resolution sea ice surface images to obtain this minimal set of parameters.
Antonio Juarez-Martinez, Javier Blasco, Alexander Robinson, Marisa Montoya, and Jorge Alvarez-Solas
The Cryosphere, 18, 4257–4283, https://doi.org/10.5194/tc-18-4257-2024, https://doi.org/10.5194/tc-18-4257-2024, 2024
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We present sea level projections for Antarctica in the context of ISMIP6-2300 with several forcings but extend the simulations to 2500, showing that more than 3 m of sea level contribution could be reached. We also test the sensitivity on a basal melting parameter and determine the timing of the loss of ice in the west region. All the simulations were carried out with the ice sheet model Yelmo.
Daniel Moreno-Parada, Alexander Robinson, Marisa Montoya, and Jorge Alvarez-Solas
The Cryosphere, 18, 4215–4232, https://doi.org/10.5194/tc-18-4215-2024, https://doi.org/10.5194/tc-18-4215-2024, 2024
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Our study tries to understand how the ice temperature evolves in a large mass as in the case of Antarctica. We found a relation that tells us the ice temperature at any point. These results are important because they also determine how the ice moves. In general, ice moves due to slow deformation (as if pouring honey from a jar). Nevertheless, in some regions the ice base warms enough and melts. The liquid water then serves as lubricant and the ice slides and its velocity increases rapidly.
Tim Hageman, Jessica Mejía, Ravindra Duddu, and Emilio Martínez-Pañeda
The Cryosphere, 18, 3991–4009, https://doi.org/10.5194/tc-18-3991-2024, https://doi.org/10.5194/tc-18-3991-2024, 2024
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Due to surface melting, meltwater lakes seasonally form on the surface of glaciers. These lakes drive hydrofractures that rapidly transfer water to the base of ice sheets. This paper presents a computational method to capture the complicated hydrofracturing process. Our work reveals that viscous ice rheology has a great influence on the short-term propagation of fractures, enabling fast lake drainage, whereas thermal effects (frictional heating, conduction, and freezing) have little influence.
Clémence Herny, Pascal Hagenmuller, Guillaume Chambon, Isabel Peinke, and Jacques Roulle
The Cryosphere, 18, 3787–3805, https://doi.org/10.5194/tc-18-3787-2024, https://doi.org/10.5194/tc-18-3787-2024, 2024
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This paper presents the evaluation of a numerical discrete element method (DEM) by simulating cone penetration tests in different snow samples. The DEM model demonstrated a good ability to reproduce the measured mechanical behaviour of the snow, namely the force evolution on the cone and the grain displacement field. Systematic sensitivity tests showed that the mechanical response depends not only on the microstructure of the sample but also on the mechanical parameters of grain contacts.
Louis Quéno, Rebecca Mott, Paul Morin, Bertrand Cluzet, Giulia Mazzotti, and Tobias Jonas
The Cryosphere, 18, 3533–3557, https://doi.org/10.5194/tc-18-3533-2024, https://doi.org/10.5194/tc-18-3533-2024, 2024
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Snow redistribution by wind and avalanches strongly influences snow hydrology in mountains. This study presents a novel modelling approach to best represent these processes in an operational context. The evaluation of the simulations against airborne snow depth measurements showed remarkable improvement in the snow distribution in mountains of the eastern Swiss Alps, with a representation of snow accumulation and erosion areas, suggesting promising benefits for operational snow melt forecasts.
André Löfgren, Thomas Zwinger, Peter Råback, Christian Helanow, and Josefin Ahlkrona
The Cryosphere, 18, 3453–3470, https://doi.org/10.5194/tc-18-3453-2024, https://doi.org/10.5194/tc-18-3453-2024, 2024
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This paper investigates a stabilization method for free-surface flows in the context of glacier simulations. Previous applications of the stabilization on ice flows have only considered simple ice-sheet benchmark problems; in particular the method had not been tested on real-world glacier domains. This work addresses this shortcoming by demonstrating that the stabilization works well also in this case and increases stability and robustness without negatively impacting computation times.
Ange Haddjeri, Matthieu Baron, Matthieu Lafaysse, Louis Le Toumelin, César Deschamps-Berger, Vincent Vionnet, Simon Gascoin, Matthieu Vernay, and Marie Dumont
The Cryosphere, 18, 3081–3116, https://doi.org/10.5194/tc-18-3081-2024, https://doi.org/10.5194/tc-18-3081-2024, 2024
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Our study addresses the complex challenge of evaluating distributed alpine snow simulations with snow transport against snow depths from Pléiades stereo imagery and snow melt-out dates from Sentinel-2 and Landsat-8 satellites. Additionally, we disentangle error contributions between blowing snow, precipitation heterogeneity, and unresolved subgrid variability. Snow transport enhances the snow simulations at high elevations, while precipitation biases are the main error source in other areas.
Richard Parsons, Sainan Sun, G. Hilmar Gudmundsson, Jan Wuite, and Thomas Nagler
EGUsphere, https://doi.org/10.5194/egusphere-2024-1499, https://doi.org/10.5194/egusphere-2024-1499, 2024
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In 2022, sea ice in Antarctica's Larsen B embayment disintegrated, after which time an increase in the rate at which Crane Glacier discharged ice into the ocean was observed. As the sea ice was attached to the terminus of the glacier, it could provide a resistive stress against the glacier’s ice-flow, slowing down the rate of ice discharge. We used numerical modelling to quantify this resistive stress and found that the sea ice provided significant support to Crane prior to its disintegration.
Christopher Riedel and Jeffrey Anderson
The Cryosphere, 18, 2875–2896, https://doi.org/10.5194/tc-18-2875-2024, https://doi.org/10.5194/tc-18-2875-2024, 2024
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Accurate sea ice conditions are crucial for quality sea ice projections, which have been connected to rapid warming over the Arctic. Knowing which observations to assimilate into models will help produce more accurate sea ice conditions. We found that not assimilating sea ice concentration led to more accurate sea ice states. The methods typically used to assimilate observations in our models apply assumptions to variables that are not well suited for sea ice because they are bounded variables.
Julia Selivanova, Doroteaciro Iovino, and Francesco Cocetta
The Cryosphere, 18, 2739–2763, https://doi.org/10.5194/tc-18-2739-2024, https://doi.org/10.5194/tc-18-2739-2024, 2024
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Climate models show differences in sea ice representation in comparison to observations. Increasing the model resolution is a recognized way to improve model realism and obtain more reliable future projections. We find no strong impact of resolution on sea ice representation; it rather depends on the analysed variable and the model used. By 2050, the marginal ice zone (MIZ) becomes a dominant feature of the Arctic ice cover, suggesting a shift to a new regime similar to that in Antarctica.
Alexander A. Robel, Vincent Verjans, and Aminat A. Ambelorun
The Cryosphere, 18, 2613–2623, https://doi.org/10.5194/tc-18-2613-2024, https://doi.org/10.5194/tc-18-2613-2024, 2024
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The average size of many glaciers and ice sheets changes when noise is added to the system. The reasons for this drift in glacier state is intrinsic to the dynamics of how ice flows and the bumpiness of the Earth's surface. We argue that not including noise in projections of ice sheet evolution over coming decades and centuries is a pervasive source of bias in these computer models, and so realistic variability in glacier and climate processes must be included in models.
Ward van Pelt and Thomas Frank
EGUsphere, https://doi.org/10.5194/egusphere-2024-1525, https://doi.org/10.5194/egusphere-2024-1525, 2024
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Accurate information on the ice thickness of Svalbard’s glaciers is important for assessing the contribution to sea level rise in a present and future climate. However, direct observations of the glacier bed are scarce. Here, we use an inverse approach and high-resolution surface observations, to infer basal conditions. We present and analyze the new bed and thickness maps, quantify the ice volume (6,800 km3), and compare against radar data and previous studies.
Georgina Jean Woolley, Nick Rutter, Leanne Wake, Vincent Vionnet, Chris Derksen, Richard Essery, Philip Marsh, Rosamund Tutton, Branden Walker, Matthieu Lafaysse, and David Pritchard
EGUsphere, https://doi.org/10.5194/egusphere-2024-1237, https://doi.org/10.5194/egusphere-2024-1237, 2024
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Parameterisations of Arctic snow processes were implemented into the multi-physics ensemble version of SVS2-Crocus and evaluated using density and SSA measurements at an Arctic tundra site. Optimal combinations of parameterisations that improved the simulation of density and SSA were identified. Top performing ensemble members featured modifications that raise wind speeds to increase compaction in surface layers, prevent snowdrift and increase viscosity in basal layers.
José M. Muñoz-Hermosilla, Jaime Otero, Eva De Andrés, Kaian Shahateet, Francisco Navarro, and Iván Pérez-Doña
The Cryosphere, 18, 1911–1924, https://doi.org/10.5194/tc-18-1911-2024, https://doi.org/10.5194/tc-18-1911-2024, 2024
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A large fraction of the mass loss from marine-terminating glaciers is attributed to frontal ablation. In this study, we used a 3D ice flow model of a real glacier that includes the effects of calving and submarine melting. Over a 30-month simulation, we found that the model reproduced the seasonal cycle for this glacier. Besides, the front positions were in good agreement with observations in the central part of the front, with longitudinal differences, on average, below 15 m.
Charlotte Durand, Tobias Sebastian Finn, Alban Farchi, Marc Bocquet, Guillaume Boutin, and Einar Ólason
The Cryosphere, 18, 1791–1815, https://doi.org/10.5194/tc-18-1791-2024, https://doi.org/10.5194/tc-18-1791-2024, 2024
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This paper focuses on predicting Arctic-wide sea-ice thickness using surrogate modeling with deep learning. The model has a predictive power of 12 h up to 6 months. For this forecast horizon, persistence and daily climatology are systematically outperformed, a result of learned thermodynamics and advection. Consequently, surrogate modeling with deep learning proves to be effective at capturing the complex behavior of sea ice.
Mathieu Plante, Jean-François Lemieux, L. Bruno Tremblay, Adrienne Tivy, Joey Angnatok, François Roy, Gregory Smith, Frédéric Dupont, and Adrian K. Turner
The Cryosphere, 18, 1685–1708, https://doi.org/10.5194/tc-18-1685-2024, https://doi.org/10.5194/tc-18-1685-2024, 2024
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We use a sea ice model to reproduce ice growth observations from two buoys deployed on coastal sea ice and analyze the improvements brought by new physics that represent the presence of saline liquid water in the ice interior. We find that the new physics with default parameters degrade the model performance, with overly rapid ice growth and overly early snow flooding on top of the ice. The performance is largely improved by simple modifications to the ice growth and snow-flooding algorithms.
Joshua Cuzzone, Matias Romero, and Shaun A. Marcott
The Cryosphere, 18, 1381–1398, https://doi.org/10.5194/tc-18-1381-2024, https://doi.org/10.5194/tc-18-1381-2024, 2024
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We simulate the retreat history of the Patagonian Ice Sheet (PIS) across the Chilean Lake District from 22–10 ka. These results improve our understanding of the response of the PIS to deglacial warming and the patterns of deglacial ice margin retreat where gaps in the geologic record still exist, and they indicate that changes in large-scale precipitation during the last deglaciation played an important role in modulating the response of ice margin change across the PIS to deglacial warming.
Chao-Yuan Yang, Jiping Liu, and Dake Chen
The Cryosphere, 18, 1215–1239, https://doi.org/10.5194/tc-18-1215-2024, https://doi.org/10.5194/tc-18-1215-2024, 2024
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We present a new atmosphere–ocean–wave–sea ice coupled model to study the influences of ocean waves on Arctic sea ice simulation. Our results show (1) smaller ice-floe size with wave breaking increases ice melt, (2) the responses in the atmosphere and ocean to smaller floe size partially reduce the effect of the enhanced ice melt, (3) the limited oceanic energy is a strong constraint for ice melt enhancement, and (4) ocean waves can indirectly affect sea ice through the atmosphere and the ocean.
Yurii Batrak, Bin Cheng, and Viivi Kallio-Myers
The Cryosphere, 18, 1157–1183, https://doi.org/10.5194/tc-18-1157-2024, https://doi.org/10.5194/tc-18-1157-2024, 2024
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Atmospheric reanalyses provide consistent series of atmospheric and surface parameters in a convenient gridded form. In this paper, we study the quality of sea ice in a recently released regional reanalysis and assess its added value compared to a global reanalysis. We show that the regional reanalysis, having a more complex sea ice model, gives an improved representation of sea ice, although there are limitations indicating potential benefits in using more advanced approaches in the future.
Michael A. Rawlins and Ambarish V. Karmalkar
The Cryosphere, 18, 1033–1052, https://doi.org/10.5194/tc-18-1033-2024, https://doi.org/10.5194/tc-18-1033-2024, 2024
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Flows of water, carbon, and materials by Arctic rivers are being altered by climate warming. We used simulations from a permafrost hydrology model to investigate future changes in quantities influencing river exports. By 2100 Arctic rivers will receive more runoff from the far north where abundant soil carbon can leach in. More water will enter them via subsurface pathways particularly in summer and autumn. An enhanced water cycle and permafrost thaw are changing river flows to coastal areas.
Oreste Marquis, Bruno Tremblay, Jean-François Lemieux, and Mohammed Islam
The Cryosphere, 18, 1013–1032, https://doi.org/10.5194/tc-18-1013-2024, https://doi.org/10.5194/tc-18-1013-2024, 2024
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We developed a standard viscous–plastic sea-ice model based on the numerical framework called smoothed particle hydrodynamics. The model conforms to the theory within an error of 1 % in an idealized ridging experiment, and it is able to simulate stable ice arches. However, the method creates a dispersive plastic wave speed. The framework is efficient to simulate fractures and can take full advantage of parallelization, making it a good candidate to investigate sea-ice material properties.
Soňa Tomaškovičová and Thomas Ingeman-Nielsen
The Cryosphere, 18, 321–340, https://doi.org/10.5194/tc-18-321-2024, https://doi.org/10.5194/tc-18-321-2024, 2024
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We present the results of a fully coupled modeling framework for simulating the ground thermal regime using only surface measurements to calibrate the thermal model. The heat conduction model is forced by surface ground temperature measurements and calibrated using the field measurements of time lapse apparent electrical resistivity. The resistivity-calibrated thermal model achieves a performance comparable to the traditional calibration of borehole temperature measurements.
Yan Huang, Liyun Zhao, Michael Wolovick, Yiliang Ma, and John C. Moore
The Cryosphere, 18, 103–119, https://doi.org/10.5194/tc-18-103-2024, https://doi.org/10.5194/tc-18-103-2024, 2024
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Geothermal heat flux (GHF) is an important factor affecting the basal thermal environment of an ice sheet and crucial for its dynamics. But it is poorly defined for the Antarctic ice sheet. We simulate the basal temperature and basal melting rate with eight different GHF datasets. We use specularity content as a two-sided constraint to discriminate between local wet or dry basal conditions. Two medium-magnitude GHF distribution maps rank well, showing that most of the inland bed area is frozen.
Matthew Drew and Lev Tarasov
The Cryosphere, 17, 5391–5415, https://doi.org/10.5194/tc-17-5391-2023, https://doi.org/10.5194/tc-17-5391-2023, 2023
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The interaction of fast-flowing regions of continental ice sheets with their beds governs how quickly they slide and therefore flow. The coupling of fast ice to its bed is controlled by the pressure of meltwater at its base. It is currently poorly understood how the physical details of these hydrologic systems affect ice speedup. Using numerical models we find, surprisingly, that they largely do not, except for the duration of the surge. This suggests that cheap models are sufficient.
Abhay Prakash, Qin Zhou, Tore Hattermann, and Nina Kirchner
The Cryosphere, 17, 5255–5281, https://doi.org/10.5194/tc-17-5255-2023, https://doi.org/10.5194/tc-17-5255-2023, 2023
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Sea ice arch formation in the Nares Strait has shielded the Petermann Glacier ice shelf from enhanced basal melting. However, with the sustained decline of the Arctic sea ice predicted to continue, the ice shelf is likely to be exposed to a year-round mobile and thin sea ice cover. In such a scenario, our modelled results show that elevated temperatures, and more importantly, a stronger ocean circulation in the ice shelf cavity, could result in up to two-thirds increase in basal melt.
Michael Wolovick, Angelika Humbert, Thomas Kleiner, and Martin Rückamp
The Cryosphere, 17, 5027–5060, https://doi.org/10.5194/tc-17-5027-2023, https://doi.org/10.5194/tc-17-5027-2023, 2023
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The friction underneath ice sheets can be inferred from observed velocity at the top, but this inference requires smoothing. The selection of smoothing has been highly variable in the literature. Here we show how to rigorously select the best smoothing, and we show that the inferred friction converges towards the best knowable field as model resolution improves. We use this to learn about the best description of basal friction and to formulate recommended best practices for other modelers.
Oliver G. Pollard, Natasha L. M. Barlow, Lauren J. Gregoire, Natalya Gomez, Víctor Cartelle, Jeremy C. Ely, and Lachlan C. Astfalck
The Cryosphere, 17, 4751–4777, https://doi.org/10.5194/tc-17-4751-2023, https://doi.org/10.5194/tc-17-4751-2023, 2023
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We use advanced statistical techniques and a simple ice-sheet model to produce an ensemble of plausible 3D shapes of the ice sheet that once stretched across northern Europe during the previous glacial maximum (140,000 years ago). This new reconstruction, equivalent in volume to 48 ± 8 m of global mean sea-level rise, will improve the interpretation of high sea levels recorded from the Last Interglacial period (120 000 years ago) that provide a useful perspective on the future.
Juditha Aga, Julia Boike, Moritz Langer, Thomas Ingeman-Nielsen, and Sebastian Westermann
The Cryosphere, 17, 4179–4206, https://doi.org/10.5194/tc-17-4179-2023, https://doi.org/10.5194/tc-17-4179-2023, 2023
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This study presents a new model scheme for simulating ice segregation and thaw consolidation in permafrost environments, depending on ground properties and climatic forcing. It is embedded in the CryoGrid community model, a land surface model for the terrestrial cryosphere. We describe the model physics and functionalities, followed by a model validation and a sensitivity study of controlling factors.
Thomas Frank, Ward J. J. van Pelt, and Jack Kohler
The Cryosphere, 17, 4021–4045, https://doi.org/10.5194/tc-17-4021-2023, https://doi.org/10.5194/tc-17-4021-2023, 2023
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Since the ice thickness of most glaciers worldwide is unknown, and since it is not feasible to visit every glacier and observe their thickness directly, inverse modelling techniques are needed that can calculate ice thickness from abundant surface observations. Here, we present a new method for doing that. Our methodology relies on modelling the rate of surface elevation change for a given glacier, compare this with observations of the same quantity and change the bed until the two are in line.
Ronja Reese, Julius Garbe, Emily A. Hill, Benoît Urruty, Kaitlin A. Naughten, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, David Chandler, Petra M. Langebroek, and Ricarda Winkelmann
The Cryosphere, 17, 3761–3783, https://doi.org/10.5194/tc-17-3761-2023, https://doi.org/10.5194/tc-17-3761-2023, 2023
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We use an ice sheet model to test where current climate conditions in Antarctica might lead. We find that present-day ocean and atmosphere conditions might commit an irreversible collapse of parts of West Antarctica which evolves over centuries to millennia. Importantly, this collapse is not irreversible yet.
Emily A. Hill, Benoît Urruty, Ronja Reese, Julius Garbe, Olivier Gagliardini, Gaël Durand, Fabien Gillet-Chaulet, G. Hilmar Gudmundsson, Ricarda Winkelmann, Mondher Chekki, David Chandler, and Petra M. Langebroek
The Cryosphere, 17, 3739–3759, https://doi.org/10.5194/tc-17-3739-2023, https://doi.org/10.5194/tc-17-3739-2023, 2023
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The grounding lines of the Antarctic Ice Sheet could enter phases of irreversible retreat or advance. We use three ice sheet models to show that the present-day locations of Antarctic grounding lines are reversible with respect to a small perturbation away from their current position. This indicates that present-day retreat of the grounding lines is not yet irreversible or self-enhancing.
Huy Dinh, Dimitrios Giannakis, Joanna Slawinska, and Georg Stadler
The Cryosphere, 17, 3883–3893, https://doi.org/10.5194/tc-17-3883-2023, https://doi.org/10.5194/tc-17-3883-2023, 2023
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We develop a numerical method to simulate the fracture in kilometer-sized chunks of floating ice in the ocean. Our approach uses a mathematical model that balances deformation energy against the energy required for fracture. We study the strength of ice chunks that contain random impurities due to prior damage or refreezing and what types of fractures are likely to occur. Our model shows that crack direction critically depends on the orientation of impurities relative to surrounding forces.
René R. Wijngaard, Adam R. Herrington, William H. Lipscomb, Gunter R. Leguy, and Soon-Il An
The Cryosphere, 17, 3803–3828, https://doi.org/10.5194/tc-17-3803-2023, https://doi.org/10.5194/tc-17-3803-2023, 2023
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We evaluate the ability of the Community Earth System Model (CESM2) to simulate cryospheric–hydrological variables, such as glacier surface mass balance (SMB), over High Mountain Asia (HMA) by using a global grid (~111 km) with regional refinement (~7 km) over HMA. Evaluations of two different simulations show that climatological biases are reduced, and glacier SMB is improved (but still too negative) by modifying the snow and glacier model and using an updated glacier cover dataset.
Brian Groenke, Moritz Langer, Jan Nitzbon, Sebastian Westermann, Guillermo Gallego, and Julia Boike
The Cryosphere, 17, 3505–3533, https://doi.org/10.5194/tc-17-3505-2023, https://doi.org/10.5194/tc-17-3505-2023, 2023
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It is now well known from long-term temperature measurements that Arctic permafrost, i.e., ground that remains continuously frozen for at least 2 years, is warming in response to climate change. Temperature, however, only tells half of the story. In this study, we use computer modeling to better understand how the thawing and freezing of water in the ground affects the way permafrost responds to climate change and what temperature trends can and cannot tell us about how permafrost is changing.
Yukihiko Onuma, Koji Fujita, Nozomu Takeuchi, Masashi Niwano, and Teruo Aoki
The Cryosphere, 17, 3309–3328, https://doi.org/10.5194/tc-17-3309-2023, https://doi.org/10.5194/tc-17-3309-2023, 2023
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We established a novel model that simulates the temporal changes in cryoconite hole (CH) depth using heat budgets calculated independently at the ice surface and CH bottom based on hole shape geometry. The simulations suggest that CH depth is governed by the balance between the intensity of the diffuse component of downward shortwave radiation and the wind speed. The meteorological conditions may be important factors contributing to the recent ice surface darkening via the redistribution of CHs.
Max Thomas, Briana Cate, Jack Garnett, Inga J. Smith, Martin Vancoppenolle, and Crispin Halsall
The Cryosphere, 17, 3193–3201, https://doi.org/10.5194/tc-17-3193-2023, https://doi.org/10.5194/tc-17-3193-2023, 2023
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A recent study showed that pollutants can be enriched in growing sea ice beyond what we would expect from a perfectly dissolved chemical. We hypothesise that this effect is caused by the specific properties of the pollutants working in combination with fluid moving through the sea ice. To test our hypothesis, we replicate this behaviour in a sea-ice model and show that this type of modelling can be applied to predicting the transport of chemicals with complex behaviour in sea ice.
Tobias Sebastian Finn, Charlotte Durand, Alban Farchi, Marc Bocquet, Yumeng Chen, Alberto Carrassi, and Véronique Dansereau
The Cryosphere, 17, 2965–2991, https://doi.org/10.5194/tc-17-2965-2023, https://doi.org/10.5194/tc-17-2965-2023, 2023
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We combine deep learning with a regional sea-ice model to correct model errors in the sea-ice dynamics of low-resolution forecasts towards high-resolution simulations. The combined model improves the forecast by up to 75 % and thereby surpasses the performance of persistence. As the error connection can additionally be used to analyse the shortcomings of the forecasts, this study highlights the potential of combined modelling for short-term sea-ice forecasting.
Saskia Kahl, Carolin Mehlmann, and Dirk Notz
EGUsphere, https://doi.org/10.5194/egusphere-2023-982, https://doi.org/10.5194/egusphere-2023-982, 2023
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Ice mélange is a mixture of sea ice and icebergs, which can have a strong influence on the sea-ice-ocean interaction. So far, ice mélange is not represented in climate models. We include icebergs into the most used sea-ice model by modifying the mathematical equations that describe the material law of sea ice. We show with three test cases that the modification is necessary to represent icebergs. Furthermore we suggest a numerical method to solve the ice mélange equations computational efficient.
Philipp de Vrese, Goran Georgievski, Jesus Fidel Gonzalez Rouco, Dirk Notz, Tobias Stacke, Norman Julius Steinert, Stiig Wilkenskjeld, and Victor Brovkin
The Cryosphere, 17, 2095–2118, https://doi.org/10.5194/tc-17-2095-2023, https://doi.org/10.5194/tc-17-2095-2023, 2023
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The current generation of Earth system models exhibits large inter-model differences in the simulated climate of the Arctic and subarctic zone. We used an adapted version of the Max Planck Institute (MPI) Earth System Model to show that differences in the representation of the soil hydrology in permafrost-affected regions could help explain a large part of this inter-model spread and have pronounced impacts on important elements of Earth systems as far to the south as the tropics.
Xia Lin, François Massonnet, Thierry Fichefet, and Martin Vancoppenolle
The Cryosphere, 17, 1935–1965, https://doi.org/10.5194/tc-17-1935-2023, https://doi.org/10.5194/tc-17-1935-2023, 2023
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This study provides clues on how improved atmospheric reanalysis products influence sea ice simulations in ocean–sea ice models. The summer ice concentration simulation in both hemispheres can be improved with changed surface heat fluxes. The winter Antarctic ice concentration and the Arctic drift speed near the ice edge and the ice velocity direction simulations are improved with changed wind stress. The radiation fluxes and winds in atmospheric reanalyses are crucial for sea ice simulations.
Cited articles
Bamber, J. L., Riva, R. E. M., Vermeersen, B. L. A., and LeBrocq, A. M.: Reassessment of the potential sea-level rise from a collapse of the West Antarctic ice sheet, Science, 324, 901–903, https://doi.org/10.1126/science.1169335, available at: http://www.sciencemag.org/content/324/5929/901.abstract, 2009.
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Dupont, T. K. and Alley, R. B.: Assessment of the importance of ice-shelf buttressing to ice-sheet flow, Geophys. Res. Lett., 32, L04503, https://doi.org/10.1029/2004GL022024, 2005.
Durand, G., Gagliardini, O., de Fleurian, D., Zwinger, T., and Meur, E. L.: Marine ice sheet dynamics: h}ysteresis and neutral equilibrium, J. Geophys. Res., 114, F03009, https://doi.org/10.1029/2008JF001170, 2009{a.
Durand, G., Gagliardini, O., Zwinger, T., Meur, E. L., and Hindmarsh, R.: Full-Stokes modeling of marine ice-sheets: influence of the grid size, Ann. Glaciol., 50, 109–114, 2009{b}.
Favier, L., Gagliardini, O., Durand, G., and Zwinger, T.: A three-dimensional full Stokes model of the grounding line dynamics: effect of a pinning point beneath the ice shelf, The Cryosphere, 6, 101–112, https://doi.org/10.5194/tc-6-101-2012, 2012.
Gagliardini, O., Durand, G., Zwinger, T., Hindmarsh, R. C. A., and Meur, E. L.: Coupling of ice-shelf melting and buttressing is a key process in ice-sheets dynamics, Geophys. Res. Lett., 37, L14501, https://doi.org/10.1029/2010GL043334, 2010.
Gladstone, R. M., Payne, A. J., and Cornford, S, L.: Resolution requirements for grounding-line modelling: sensitivity to basal drage and ice-shelf buttressing. Ann. Glaciol., 53, 97–105, https://doi.org/10.3189/2012AoG60A148, 2012.
Goldberg, D., Holland, D. M., and Schoof, C.: Grounding line movement and ice shelf buttressing in marine ice sheets, J. Geophys. Res., 114, F04026, https://doi.org/10.1029/2008JF001227, 2009.
Gudmundsson, G. H.: Analytical solutions for the surface response to small amplitude perturbations in boundary data in the shallow-ice-stream approximation, The Cryosphere, 2, 77–93, https://doi.org/10.5194/tc-2-77-2008, 2008.
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Hindmarsh, R. C. A.: Stability of ice rises and uncoupled marine ice sheets, Ann. Glaciol., 23, 94–104, 1996.
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Katz, R. F. and Worster, M. G.: Stability of ice-sheet grounding lines, P. Roy. Soc. A. Math., Phys., 466, 1597–1620, https://doi.org/10.1098/rspa.2009.0434, 2010.
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Pattyn, F., Schoof, C., Perichon, L., Hindmarsh, R. C. A., Bueler, E., de Fleurian, B., Durand, G., Gagliardini, O., Gladstone, R., Goldberg, D., Gudmundsson, G. H., Huybrechts, P., Lee, V., Nick, F. M., Payne, A. J., Pollard, D., Rybak, O., Saito, F., and Vieli, A.: Results of the Marine Ice Sheet Model Intercomparison Project, MISMIP, The Cryosphere, 6, 573–588, https://doi.org/10.5194/tc-6-573-2012, 2012.
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Schoof, C.: Ice sheet grounding line dynamics: s}teady states, stability, and hysteresis, J. Geophys. Res., 112, F03S28, https://doi.org/10.1029/2006JF000664, 2007{a.
Schoof, C.: Marine ice-sheet dynamics, part 1, The case of rapid sliding, J. Fluid. Mech., 573, 27–55, https://doi.org/10.1017/S0022112006003570, 2007{b}.
Thomas, R. H. and Bentley, C. R.: A model for Holocene retreat of the West Antarctic ice sheet, Quaternary Res., 10, 150–170, https://doi.org/10.1016/0033-5894(78)90098-4, available at: http://www.sciencedirect.com/science/article/pii/0033589478900984, 1978.
Vieli, A. and Payne, A. J.: Assessing the ability of numerical ice sheet models to simulate grounding line migration, J. Geophys. Res., 110, F01003, https://doi.org/10.1029/2004JF000202, 2005.
Walker, R. T., Dupont, T. K., Parizek, B. R., and Alley, R. B.: Effects of basal-melting distribution on the retreat of ice-shelf grounding lines, Geophys. Res. Lett., 35, L17503, https://doi.org/10.1029/2008GL034947, 2008.
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