Articles | Volume 16, issue 5
https://doi.org/10.5194/tc-16-1927-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-16-1927-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
20 May 2022
Research article |
| 20 May 2022
| 20 May 2022
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations
Johannes Feldmann
CORRESPONDING AUTHOR
Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany
Ronja Reese
Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany
Department of Geography and Environmental Sciences, Northumbria University, Newcastle, UK
Ricarda Winkelmann
Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany
Institute of Physics, University of Potsdam, Potsdam, Germany
Anders Levermann
Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany
Institute of Physics, University of Potsdam, Potsdam, Germany
LDEO, Columbia University, New York, USA
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The study investigates how changing sea levels around Antarctica can potentially affect the floating ice shelves. It utilizes numerical models for both the Antarctic Ice Sheet and the solid Earth, investigating features like troughs and sills that control the flow of ocean water onto the continental shelf. The research finds that variations in sea level alone can significantly impact the melting rates of ice shelves.
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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.
Johanna Beckmann and Ricarda Winkelmann
The Cryosphere, 17, 3083–3099, https://doi.org/10.5194/tc-17-3083-2023, https://doi.org/10.5194/tc-17-3083-2023, 2023
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Over the past decade, Greenland has experienced several extreme melt events.
With progressing climate change, such extreme melt events can be expected to occur more frequently and potentially become more severe and persistent.
Strong melt events may considerably contribute to Greenland's mass loss, which in turn strongly determines future sea level rise. How important these extreme melt events could be in the future is assessed in this study for the first time.
E. Keith Smith, Marc Wiedermann, Jonathan F. Donges, Jobst Heitzig, and Ricarda Winkelmann
EGUsphere, https://doi.org/10.5194/egusphere-2023-1622, https://doi.org/10.5194/egusphere-2023-1622, 2023
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Lena Nicola, Dirk Notz, and Ricarda Winkelmann
The Cryosphere, 17, 2563–2583, https://doi.org/10.5194/tc-17-2563-2023, https://doi.org/10.5194/tc-17-2563-2023, 2023
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Johannes Feldmann and Anders Levermann
The Cryosphere, 17, 327–348, https://doi.org/10.5194/tc-17-327-2023, https://doi.org/10.5194/tc-17-327-2023, 2023
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Clara Burgard, Nicolas C. Jourdain, Ronja Reese, Adrian Jenkins, and Pierre Mathiot
The Cryosphere, 16, 4931–4975, https://doi.org/10.5194/tc-16-4931-2022, https://doi.org/10.5194/tc-16-4931-2022, 2022
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The ocean-induced melt at the base of the floating ice shelves around Antarctica is one of the largest uncertainty factors in the Antarctic contribution to future sea-level rise. We assess the performance of several existing parameterisations in simulating basal melt rates on a circum-Antarctic scale, using an ocean simulation resolving the cavities below the shelves as our reference. We find that the simple quadratic slope-independent and plume parameterisations yield the best compromise.
Maria Zeitz, Jan M. Haacker, Jonathan F. Donges, Torsten Albrecht, and Ricarda Winkelmann
Earth Syst. Dynam., 13, 1077–1096, https://doi.org/10.5194/esd-13-1077-2022, https://doi.org/10.5194/esd-13-1077-2022, 2022
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Tanja Schlemm, Johannes Feldmann, Ricarda Winkelmann, and Anders Levermann
The Cryosphere, 16, 1979–1996, https://doi.org/10.5194/tc-16-1979-2022, https://doi.org/10.5194/tc-16-1979-2022, 2022
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Maria Zeitz, Ronja Reese, Johanna Beckmann, Uta Krebs-Kanzow, and Ricarda Winkelmann
The Cryosphere, 15, 5739–5764, https://doi.org/10.5194/tc-15-5739-2021, https://doi.org/10.5194/tc-15-5739-2021, 2021
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With the increasing melt of the Greenland Ice Sheet, which contributes to sea level rise, the surface of the ice darkens. The dark surfaces absorb more radiation and thus experience increased melt, resulting in the melt–albedo feedback. Using a simple surface melt model, we estimate that this positive feedback contributes to an additional 60 % ice loss in a high-warming scenario and additional 90 % ice loss for moderate warming. Albedo changes are important for Greenland’s future ice loss.
Moritz Kreuzer, Ronja Reese, Willem Nicholas Huiskamp, Stefan Petri, Torsten Albrecht, Georg Feulner, and Ricarda Winkelmann
Geosci. Model Dev., 14, 3697–3714, https://doi.org/10.5194/gmd-14-3697-2021, https://doi.org/10.5194/gmd-14-3697-2021, 2021
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We present the technical implementation of a coarse-resolution coupling between an ice sheet model and an ocean model that allows one to simulate ice–ocean interactions at timescales from centuries to millennia. As ice shelf cavities cannot be resolved in the ocean model at coarse resolution, we bridge the gap using an sub-shelf cavity module. It is shown that the framework is computationally efficient, conserves mass and energy, and can produce a stable coupled state under present-day forcing.
Nico Wunderling, Jonathan F. Donges, Jürgen Kurths, and Ricarda Winkelmann
Earth Syst. Dynam., 12, 601–619, https://doi.org/10.5194/esd-12-601-2021, https://doi.org/10.5194/esd-12-601-2021, 2021
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In the Earth system, climate tipping elements exist that can undergo qualitative changes in response to environmental perturbations. If triggered, this would result in severe consequences for the biosphere and human societies. We quantify the risk of tipping cascades using a conceptual but fully dynamic network approach. We uncover that the risk of tipping cascades under global warming scenarios is enormous and find that the continental ice sheets are most likely to initiate these failures.
Anja Katzenberger, Jacob Schewe, Julia Pongratz, and Anders Levermann
Earth Syst. Dynam., 12, 367–386, https://doi.org/10.5194/esd-12-367-2021, https://doi.org/10.5194/esd-12-367-2021, 2021
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All state-of-the-art global climate models that contributed to the latest Coupled Model Intercomparison Project (CMIP6) show a robust increase in Indian summer monsoon rainfall that is even stronger than in the previous intercomparison (CMIP5). Furthermore, they show an increase in the year-to-year variability of this seasonal rainfall that crucially influences the livelihood of more than 1 billion people in India.
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.
Tanja Schlemm and Anders Levermann
The Cryosphere, 15, 531–545, https://doi.org/10.5194/tc-15-531-2021, https://doi.org/10.5194/tc-15-531-2021, 2021
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Ice loss from Greenland and Antarctica is often cloaked by a mélange of icebergs and sea ice. Here we provide a simple method to parametrize the resulting back stress on the ice flow for large-scale projection models.
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.
Maria Zeitz, Anders Levermann, and Ricarda Winkelmann
The Cryosphere, 14, 3537–3550, https://doi.org/10.5194/tc-14-3537-2020, https://doi.org/10.5194/tc-14-3537-2020, 2020
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The flow of ice drives mass losses in the large ice sheets. Sea-level rise projections rely on ice-sheet models, solving the physics of ice flow and melt. Unfortunately the parameters in the physics of flow are uncertain. Here we show, in an idealized setup, that these uncertainties can double flow-driven mass losses within the possible range of parameters. It is possible that this uncertainty carries over to realistic sea-level rise projections.
Hélène Seroussi, Sophie Nowicki, Antony J. Payne, Heiko Goelzer, William H. Lipscomb, Ayako Abe-Ouchi, Cécile Agosta, Torsten Albrecht, Xylar Asay-Davis, Alice Barthel, Reinhard Calov, Richard Cullather, Christophe Dumas, Benjamin K. Galton-Fenzi, Rupert Gladstone, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Tore Hattermann, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Nicolas C. Jourdain, Thomas Kleiner, Eric Larour, Gunter R. Leguy, Daniel P. Lowry, Chistopher M. Little, Mathieu Morlighem, Frank Pattyn, Tyler Pelle, Stephen F. Price, Aurélien Quiquet, Ronja Reese, Nicole-Jeanne Schlegel, Andrew Shepherd, Erika Simon, Robin S. Smith, Fiammetta Straneo, Sainan Sun, Luke D. Trusel, Jonas Van Breedam, Roderik S. W. van de Wal, Ricarda Winkelmann, Chen Zhao, Tong Zhang, and Thomas Zwinger
The Cryosphere, 14, 3033–3070, https://doi.org/10.5194/tc-14-3033-2020, https://doi.org/10.5194/tc-14-3033-2020, 2020
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The Antarctic ice sheet has been losing mass over at least the past 3 decades in response to changes in atmospheric and oceanic conditions. This study presents an ensemble of model simulations of the Antarctic evolution over the 2015–2100 period based on various ice sheet models, climate forcings and emission scenarios. Results suggest that the West Antarctic ice sheet will continue losing a large amount of ice, while the East Antarctic ice sheet could experience increased snow accumulation.
Ronja Reese, Anders Levermann, Torsten Albrecht, Hélène Seroussi, and Ricarda Winkelmann
The Cryosphere, 14, 3097–3110, https://doi.org/10.5194/tc-14-3097-2020, https://doi.org/10.5194/tc-14-3097-2020, 2020
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We compare 21st century projections of Antarctica's future sea-level contribution simulated with the Parallel Ice Sheet Model submitted to ISMIP6 with projections following the LARMIP-2 protocol based on the same model configuration. We find that (1) a preceding historic simulation increases mass loss by 5–50 % and that (2) the order of magnitude difference in the ice loss in our experiments following the two protocols can be explained by the translation of ocean forcing to sub-shelf melting.
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.
Torsten Albrecht, Ricarda Winkelmann, and Anders Levermann
The Cryosphere, 14, 633–656, https://doi.org/10.5194/tc-14-633-2020, https://doi.org/10.5194/tc-14-633-2020, 2020
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A large ensemble of glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM) was analyzed in which four relevant model parameters were systematically varied. These parameters were selected in a companion study and are associated with uncertainties in ice dynamics, climatic forcing, basal sliding and solid Earth deformation. For each ensemble member a statistical score is computed, which enables calibrating the model against both modern and geologic data.
Torsten Albrecht, Ricarda Winkelmann, and Anders Levermann
The Cryosphere, 14, 599–632, https://doi.org/10.5194/tc-14-599-2020, https://doi.org/10.5194/tc-14-599-2020, 2020
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During the last glacial cycles the Antarctic Ice Sheet experienced alternating climatic conditions and varying sea-level history. In response, changes in ice sheet volume and ice-covered area occurred, implying feedbacks on the global sea level. We ran model simulations of the ice sheet with the Parallel Ice Sheet Model (PISM) over the last two glacial cycles to evaluate the model's sensitivity to different choices of boundary conditions and parameters to gain confidence for future projections.
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.
Falko Ueckerdt, Katja Frieler, Stefan Lange, Leonie Wenz, Gunnar Luderer, and Anders Levermann
Earth Syst. Dynam., 10, 741–763, https://doi.org/10.5194/esd-10-741-2019, https://doi.org/10.5194/esd-10-741-2019, 2019
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We compute the global mean temperature increase at which the costs from climate-change damages and climate-change mitigation are minimal. This temperature is computed robustly around 2 degrees of global warming across a wide range of normative assumptions on the valuation of future welfare and inequality aversion.
Tanja Schlemm and Anders Levermann
The Cryosphere, 13, 2475–2488, https://doi.org/10.5194/tc-13-2475-2019, https://doi.org/10.5194/tc-13-2475-2019, 2019
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We provide a simple stress-based parameterization for cliff calving of ice sheets. According to the resulting increasing dependence of the calving rate on ice thickness, the parameterization might lead to a runaway ice loss in large parts of Greenland and Antarctica.
Anders Levermann and Johannes Feldmann
The Cryosphere, 13, 1621–1633, https://doi.org/10.5194/tc-13-1621-2019, https://doi.org/10.5194/tc-13-1621-2019, 2019
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Using scaling analysis we propose that the currently observed marine ice-sheet instability in the Amundsen Sea sector might be faster than all other potential instabilities in Antarctica.
Hélène Seroussi, Sophie Nowicki, Erika Simon, Ayako Abe-Ouchi, Torsten Albrecht, Julien Brondex, Stephen Cornford, Christophe Dumas, Fabien Gillet-Chaulet, Heiko Goelzer, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Thomas Kleiner, Eric Larour, Gunter Leguy, William H. Lipscomb, Daniel Lowry, Matthias Mengel, Mathieu Morlighem, Frank Pattyn, Anthony J. Payne, David Pollard, Stephen F. Price, Aurélien Quiquet, Thomas J. Reerink, Ronja Reese, Christian B. Rodehacke, Nicole-Jeanne Schlegel, Andrew Shepherd, Sainan Sun, Johannes Sutter, Jonas Van Breedam, Roderik S. W. van de Wal, Ricarda Winkelmann, and Tong Zhang
The Cryosphere, 13, 1441–1471, https://doi.org/10.5194/tc-13-1441-2019, https://doi.org/10.5194/tc-13-1441-2019, 2019
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We compare a wide range of Antarctic ice sheet simulations with varying initialization techniques and model parameters to understand the role they play on the projected evolution of this ice sheet under simple scenarios. Results are improved compared to previous assessments and show that continued improvements in the representation of the floating ice around Antarctica are critical to reduce the uncertainty in the future ice sheet contribution to sea level rise.
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.
Johannes Feldmann, Ronja Reese, Ricarda Winkelmann, and Anders Levermann
The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-109, https://doi.org/10.5194/tc-2018-109, 2018
Revised manuscript not accepted
Ronja Reese, Torsten Albrecht, Matthias Mengel, Xylar Asay-Davis, and Ricarda Winkelmann
The Cryosphere, 12, 1969–1985, https://doi.org/10.5194/tc-12-1969-2018, https://doi.org/10.5194/tc-12-1969-2018, 2018
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Floating ice shelves surround most of Antarctica and ocean-driven melting at their bases is a major reason for its current sea-level contribution. We developed a simple model based on a box model approach that captures the vertical ocean circulation generally present in ice-shelf cavities and allows simulating melt rates in accordance with physical processes beneath the ice. We test the model for all Antarctic ice shelves and find that melt rates and melt patterns agree well with observations.
Johannes Feldmann and Anders Levermann
The Cryosphere, 11, 1913–1932, https://doi.org/10.5194/tc-11-1913-2017, https://doi.org/10.5194/tc-11-1913-2017, 2017
Jacob Schewe and Anders Levermann
Earth Syst. Dynam., 8, 495–505, https://doi.org/10.5194/esd-8-495-2017, https://doi.org/10.5194/esd-8-495-2017, 2017
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Monsoon systems have undergone abrupt changes in past climates, and theoretical considerations show that threshold behavior can follow from the internal dynamics of monsoons. So far, however, the possibility of abrupt changes has not been explored for modern monsoon systems. We analyze state-of-the-art climate model simulations and show that some models project abrupt changes in Sahel rainfall in response to a dynamic shift in the West African monsoon under 21st century climate change.
Jan Wohland, Torsten Albrecht, and Anders Levermann
The Cryosphere Discuss., https://doi.org/10.5194/tc-2016-191, https://doi.org/10.5194/tc-2016-191, 2016
Preprint withdrawn
Anders Levermann and Ricarda Winkelmann
The Cryosphere, 10, 1799–1807, https://doi.org/10.5194/tc-10-1799-2016, https://doi.org/10.5194/tc-10-1799-2016, 2016
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In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. Here we derive the basic equations for the melt elevation feedback that can lead to self-amplifying melt of the Greenland Ice Sheet and ice sheets in general. The theory unifies the results of complex models when the feedback dominates the dynamics and it allows us to estimate the melt time of ice sheets from data in cases where ice dynamic loss can be neglected.
Johannes Feldmann and Anders Levermann
The Cryosphere, 10, 1753–1769, https://doi.org/10.5194/tc-10-1753-2016, https://doi.org/10.5194/tc-10-1753-2016, 2016
K. Frieler, M. Mengel, and A. Levermann
Earth Syst. Dynam., 7, 203–210, https://doi.org/10.5194/esd-7-203-2016, https://doi.org/10.5194/esd-7-203-2016, 2016
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Sea level will continue to rise for centuries. We investigate the option of delaying sea-level rise by pumping ocean water onto Antarctica. Due to wave propagation ice is discharged much faster back into the ocean than expected from pure advection. A millennium-scale storage of > 80 % of the additional ice requires a distance of > 700 km from the coastline. The pumping energy required to elevate ocean water to mitigate a sea-level rise of 3 mm yr−1 exceeds 7 % of current global primary energy supply.
K. Frieler, A. Levermann, J. Elliott, J. Heinke, A. Arneth, M. F. P. Bierkens, P. Ciais, D. B. Clark, D. Deryng, P. Döll, P. Falloon, B. Fekete, C. Folberth, A. D. Friend, C. Gellhorn, S. N. Gosling, I. Haddeland, N. Khabarov, M. Lomas, Y. Masaki, K. Nishina, K. Neumann, T. Oki, R. Pavlick, A. C. Ruane, E. Schmid, C. Schmitz, T. Stacke, E. Stehfest, Q. Tang, D. Wisser, V. Huber, F. Piontek, L. Warszawski, J. Schewe, H. Lotze-Campen, and H. J. Schellnhuber
Earth Syst. Dynam., 6, 447–460, https://doi.org/10.5194/esd-6-447-2015, https://doi.org/10.5194/esd-6-447-2015, 2015
J. Feldmann and A. Levermann
The Cryosphere, 9, 631–645, https://doi.org/10.5194/tc-9-631-2015, https://doi.org/10.5194/tc-9-631-2015, 2015
M. A. Martin, A. Levermann, and R. Winkelmann
The Cryosphere Discuss., https://doi.org/10.5194/tcd-9-1705-2015, https://doi.org/10.5194/tcd-9-1705-2015, 2015
Preprint withdrawn
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Numerical ice sheet modelling shows that idealized, step-function type ocean warming in the Weddell Sea, where the ice sheet is close to floatation, leads to more immediate ice discharge with a higher sensitivity to small warming levels than the same warming in the Amundsen Sea. While the cumulative ice loss in the Amundsen Sea Sector is of similar magnitude after five centuries of continued warming, ice loss increases at a slower pace and only for significantly higher warming levels.
D. Ehlert and A. Levermann
Earth Syst. Dynam., 5, 383–397, https://doi.org/10.5194/esd-5-383-2014, https://doi.org/10.5194/esd-5-383-2014, 2014
A. Levermann, R. Winkelmann, S. Nowicki, J. L. Fastook, K. Frieler, R. Greve, H. H. Hellmer, M. A. Martin, M. Meinshausen, M. Mengel, A. J. Payne, D. Pollard, T. Sato, R. Timmermann, W. L. Wang, and R. A. Bindschadler
Earth Syst. Dynam., 5, 271–293, https://doi.org/10.5194/esd-5-271-2014, https://doi.org/10.5194/esd-5-271-2014, 2014
T. Albrecht and A. Levermann
The Cryosphere, 8, 587–605, https://doi.org/10.5194/tc-8-587-2014, https://doi.org/10.5194/tc-8-587-2014, 2014
C. F. Schleussner, J. Runge, J. Lehmann, and A. Levermann
Earth Syst. Dynam., 5, 103–115, https://doi.org/10.5194/esd-5-103-2014, https://doi.org/10.5194/esd-5-103-2014, 2014
A. Menon, A. Levermann, J. Schewe, J. Lehmann, and K. Frieler
Earth Syst. Dynam., 4, 287–300, https://doi.org/10.5194/esd-4-287-2013, https://doi.org/10.5194/esd-4-287-2013, 2013
Related subject area
Discipline: Ice sheets | Subject: Ice Shelf
An analysis of the interaction between surface and basal crevasses in ice shelves
The importance of cloud properties when assessing surface melting in an offline-coupled firn model over Ross Ice shelf, West Antarctica
Coupled ice–ocean interactions during future retreat of West Antarctic ice streams in the Amundsen Sea sector
Responses of the Pine Island and Thwaites glaciers to melt and sliding parameterizations
Extreme melting at Greenland's largest floating ice tongue
The complex basal morphology and ice dynamics of the Nansen Ice Shelf, East Antarctica
Unveiling spatial variability within the Dotson Melt Channel through high-resolution basal melt rates from the Reference Elevation Model of Antarctica
Brief communication: Is vertical shear in an ice shelf (still) negligible?
Change in Antarctic ice shelf area from 2009 to 2019
Predicting ocean-induced ice-shelf melt rates using deep learning
Glaciological history and structural evolution of the Shackleton Ice Shelf system, East Antarctica, over the past 60 years
An assessment of basal melt parameterisations for Antarctic ice shelves
Surface melt on the Shackleton Ice Shelf, East Antarctica (2003–2021)
The effect of hydrology and crevasse wall contact on calving
On the evolution of an ice shelf melt channel at the base of Filchner Ice Shelf, from observations and viscoelastic modeling
Ongoing grounding line retreat and fracturing initiated at the Petermann Glacier ice shelf, Greenland, after 2016
Basal melt of the southern Filchner Ice Shelf, Antarctica
Automatic delineation of cracks with Sentinel-1 interferometry for monitoring ice shelf damage and calving
Weakening of the pinning point buttressing Thwaites Glacier, West Antarctica
Ice-shelf ocean boundary layer dynamics from large-eddy simulations
The potential of synthetic aperture radar interferometry for assessing meltwater lake dynamics on Antarctic ice shelves
Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
Mechanics and dynamics of pinning points on the Shirase Coast, West Antarctica
Evidence for a grounding line fan at the onset of a basal channel under the ice shelf of Support Force Glacier, Antarctica, revealed by reflection seismics
The 32-year record-high surface melt in 2019/2020 on the northern George VI Ice Shelf, Antarctic Peninsula
The 2020 Larsen C Ice Shelf surface melt is a 40-year record high
Diagnosing the sensitivity of grounding-line flux to changes in sub-ice-shelf melting
A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections
Lateral meltwater transfer across an Antarctic ice shelf
Ice shelf rift propagation: stability, three-dimensional effects, and the role of marginal weakening
Getz Ice Shelf melt enhanced by freshwater discharge from beneath the West Antarctic Ice Sheet
Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones
Ice shelf basal melt rates from a high-resolution digital elevation model (DEM) record for Pine Island Glacier, Antarctica
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars
Past and future dynamics of the Brunt Ice Shelf from seabed bathymetry and ice shelf geometry
Maryam Zarrinderakht, Christian Schoof, and Anthony Peirce
The Cryosphere, 18, 3841–3856, https://doi.org/10.5194/tc-18-3841-2024, https://doi.org/10.5194/tc-18-3841-2024, 2024
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The objective of the study is to understand the interactions between surface and basal crevasses by conducting a stability analysis and addressing the implications of the findings for potential calving laws. The study's findings indicate that, while the propagation of one crack in the case of two aligned surface and basal crevasses does not significantly reinforce the propagation of the other, the presence of multiple crevasses on one side enhances stability and decreases crack propagation.
Nicolaj Hansen, Andrew Orr, Xun Zou, Fredrik Boberg, Thomas J. Bracegirdle, Ella Gilbert, Peter L. Langen, Matthew A. Lazzara, Ruth Mottram, Tony Phillips, Ruth Price, Sebastian B. Simonsen, and Stuart Webster
The Cryosphere, 18, 2897–2916, https://doi.org/10.5194/tc-18-2897-2024, https://doi.org/10.5194/tc-18-2897-2024, 2024
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We investigated a melt event over the Ross Ice Shelf. We use regional climate models and a firn model to simulate the melt and compare the results with satellite data. We find that the firn model aligned well with observed melt days in certain parts of the ice shelf. The firn model had challenges accurately simulating the melt extent in the western sector. We identified potential reasons for these discrepancies, pointing to limitations in the models related to representing the cloud properties.
David T. Bett, Alexander T. Bradley, C. Rosie Williams, Paul R. Holland, Robert J. Arthern, and Daniel N. Goldberg
The Cryosphere, 18, 2653–2675, https://doi.org/10.5194/tc-18-2653-2024, https://doi.org/10.5194/tc-18-2653-2024, 2024
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A new ice–ocean model simulates future ice sheet evolution in the Amundsen Sea sector of Antarctica. Substantial ice retreat is simulated in all scenarios, with some retreat still occurring even with no future ocean melting. The future of small "pinning points" (islands of ice that contact the seabed) is an important control on this retreat. Ocean melting is crucial in causing these features to go afloat, providing the link by which climate change may affect this sector's sea level contribution.
Ian Joughin, Daniel Shapero, and Pierre Dutrieux
The Cryosphere, 18, 2583–2601, https://doi.org/10.5194/tc-18-2583-2024, https://doi.org/10.5194/tc-18-2583-2024, 2024
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The Pine Island and Thwaites glaciers are losing ice to the ocean rapidly as warmer water melts their floating ice shelves. Models help determine how much such glaciers will contribute to sea level. We find that ice loss varies in response to how much melting the ice shelves are subjected to. Our estimated losses are also sensitive to how much the friction beneath the glaciers is reduced as it goes afloat. Melt-forced sea level rise from these glaciers is likely to be less than 10 cm by 2300.
Ole Zeising, Niklas Neckel, Nils Dörr, Veit Helm, Daniel Steinhage, Ralph Timmermann, and Angelika Humbert
The Cryosphere, 18, 1333–1357, https://doi.org/10.5194/tc-18-1333-2024, https://doi.org/10.5194/tc-18-1333-2024, 2024
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The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier.
Christine F. Dow, Derek Mueller, Peter Wray, Drew Friedrichs, Alexander L. Forrest, Jasmin B. McInerney, Jamin Greenbaum, Donald D. Blankenship, Choon Ki Lee, and Won Sang Lee
The Cryosphere, 18, 1105–1123, https://doi.org/10.5194/tc-18-1105-2024, https://doi.org/10.5194/tc-18-1105-2024, 2024
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Ice shelves are a key control on Antarctic contribution to sea level rise. We examine the Nansen Ice Shelf in East Antarctica using a combination of field-based and satellite data. We find the basal topography of the ice shelf is highly variable, only partially visible in satellite datasets. We also find that the thinnest region of the ice shelf is altered over time by ice flow rates and ocean melting. These processes can cause fractures to form that eventually result in large calving events.
Ann-Sofie Priergaard Zinck, Bert Wouters, Erwin Lambert, and Stef Lhermitte
The Cryosphere, 17, 3785–3801, https://doi.org/10.5194/tc-17-3785-2023, https://doi.org/10.5194/tc-17-3785-2023, 2023
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The ice shelves in Antarctica are melting from below, which puts their stability at risk. Therefore, it is important to observe how much and where they are melting. In this study we use high-resolution satellite imagery to derive 50 m resolution basal melt rates of the Dotson Ice Shelf. With the high resolution of our product we are able to uncover small-scale features which may in the future help us to understand the state and fate of the Antarctic ice shelves and their (in)stability.
Chris Miele, Timothy C. Bartholomaus, and Ellyn M. Enderlin
The Cryosphere, 17, 2701–2704, https://doi.org/10.5194/tc-17-2701-2023, https://doi.org/10.5194/tc-17-2701-2023, 2023
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Vertical shear stress (the stress orientation usually associated with vertical gradients in horizontal velocities) is a key component of the stress balance of ice shelves. However, partly due to historical assumptions, vertical shear is often misspoken of today as
negligiblein ice shelf models. We address this miscommunication, providing conceptual guidance regarding this often misrepresented stress. Fundamentally, vertical shear is required to balance thickness gradients in ice shelves.
Julia R. Andreasen, Anna E. Hogg, and Heather L. Selley
The Cryosphere, 17, 2059–2072, https://doi.org/10.5194/tc-17-2059-2023, https://doi.org/10.5194/tc-17-2059-2023, 2023
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There are few long-term, high spatial resolution observations of ice shelf change in Antarctica over the past 3 decades. In this study, we use high spatial resolution observations to map the annual calving front location on 34 ice shelves around Antarctica from 2009 to 2019 using satellite data. The results provide a comprehensive assessment of ice front migration across Antarctica over the last decade.
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.
Sarah S. Thompson, Bernd Kulessa, Adrian Luckman, Jacqueline A. Halpin, Jamin S. Greenbaum, Tyler Pelle, Feras Habbal, Jingxue Guo, Lenneke M. Jong, Jason L. Roberts, Bo Sun, and Donald D. Blankenship
The Cryosphere, 17, 157–174, https://doi.org/10.5194/tc-17-157-2023, https://doi.org/10.5194/tc-17-157-2023, 2023
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We use satellite imagery and ice penetrating radar to investigate the stability of the Shackleton system in East Antarctica. We find significant changes in surface structures across the system and observe a significant increase in ice flow speed (up to 50 %) on the floating part of Scott Glacier. We conclude that knowledge remains woefully insufficient to explain recent observed changes in the grounded and floating regions of the system.
Clara Burgard, Nicolas C. Jourdain, Ronja Reese, Adrian Jenkins, and Pierre Mathiot
The Cryosphere, 16, 4931–4975, https://doi.org/10.5194/tc-16-4931-2022, https://doi.org/10.5194/tc-16-4931-2022, 2022
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The ocean-induced melt at the base of the floating ice shelves around Antarctica is one of the largest uncertainty factors in the Antarctic contribution to future sea-level rise. We assess the performance of several existing parameterisations in simulating basal melt rates on a circum-Antarctic scale, using an ocean simulation resolving the cavities below the shelves as our reference. We find that the simple quadratic slope-independent and plume parameterisations yield the best compromise.
Dominic Saunderson, Andrew Mackintosh, Felicity McCormack, Richard Selwyn Jones, and Ghislain Picard
The Cryosphere, 16, 4553–4569, https://doi.org/10.5194/tc-16-4553-2022, https://doi.org/10.5194/tc-16-4553-2022, 2022
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We investigate the variability in surface melt on the Shackleton Ice Shelf in East Antarctica over the last 2 decades (2003–2021). Using daily satellite observations and the machine learning approach of a self-organising map, we identify nine distinct spatial patterns of melt. These patterns allow comparisons of melt within and across melt seasons and highlight the importance of both air temperatures and local controls such as topography, katabatic winds, and albedo in driving surface melt.
Maryam Zarrinderakht, Christian Schoof, and Anthony Peirce
The Cryosphere, 16, 4491–4512, https://doi.org/10.5194/tc-16-4491-2022, https://doi.org/10.5194/tc-16-4491-2022, 2022
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Iceberg calving is the reason for more than half of mass loss in both Greenland and Antarctica and indirectly contributes to sea-level rise. Our study models iceberg calving by linear elastic fracture mechanics and uses a boundary element method to compute crack tip propagation. This model handles the contact condition: preventing crack faces from penetrating into each other and enabling the derivation of calving laws for different forms of hydrological forcing.
Angelika Humbert, Julia Christmann, Hugh F. J. Corr, Veit Helm, Lea-Sophie Höyns, Coen Hofstede, Ralf Müller, Niklas Neckel, Keith W. Nicholls, Timm Schultz, Daniel Steinhage, Michael Wolovick, and Ole Zeising
The Cryosphere, 16, 4107–4139, https://doi.org/10.5194/tc-16-4107-2022, https://doi.org/10.5194/tc-16-4107-2022, 2022
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Ice shelves are normally flat structures that fringe the Antarctic continent. At some locations they have channels incised into their underside. On Filchner Ice Shelf, such a channel is more than 50 km long and up to 330 m high. We conducted field measurements of basal melt rates and found a maximum of 2 m yr−1. Simulations represent the geometry evolution of the channel reasonably well. There is no reason to assume that this type of melt channel is destabilizing ice shelves.
Romain Millan, Jeremie Mouginot, Anna Derkacheva, Eric Rignot, Pietro Milillo, Enrico Ciraci, Luigi Dini, and Anders Bjørk
The Cryosphere, 16, 3021–3031, https://doi.org/10.5194/tc-16-3021-2022, https://doi.org/10.5194/tc-16-3021-2022, 2022
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We detect for the first time a dramatic retreat of the grounding line of Petermann Glacier, a major glacier of the Greenland Ice Sheet. Using satellite data, we also observe a speedup of the glacier and a fracturing of the ice shelf. This sequence of events is coherent with ocean warming in this region and suggests that Petermann Glacier has initiated a phase of destabilization, which is of prime importance for the stability and future contribution of the Greenland Ice Sheet to sea level rise.
Ole Zeising, Daniel Steinhage, Keith W. Nicholls, Hugh F. J. Corr, Craig L. Stewart, and Angelika Humbert
The Cryosphere, 16, 1469–1482, https://doi.org/10.5194/tc-16-1469-2022, https://doi.org/10.5194/tc-16-1469-2022, 2022
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Remote-sensing-derived basal melt rates of ice shelves are of great importance due to their capability to cover larger areas. We performed in situ measurements with a phase-sensitive radar on the southern Filchner Ice Shelf, showing moderate melt rates and low small-scale spatial variability. The comparison with remote-sensing-based melt rates revealed large differences caused by the estimation of vertical strain rates from remote sensing velocity fields that modern fields can overcome.
Ludivine Libert, Jan Wuite, and Thomas Nagler
The Cryosphere, 16, 1523–1542, https://doi.org/10.5194/tc-16-1523-2022, https://doi.org/10.5194/tc-16-1523-2022, 2022
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Open fractures are important to monitor because they weaken the ice shelf structure. We propose a novel approach using synthetic aperture radar (SAR) interferometry for automatic delineation of ice shelf cracks. The method is applied to Sentinel-1 images of Brunt Ice Shelf, Antarctica, and the propagation of the North Rift, which led to iceberg calving in February 2021, is traced. It is also shown that SAR interferometry is more sensitive to rifting than SAR backscatter and optical imagery.
Christian T. Wild, Karen E. Alley, Atsuhiro Muto, Martin Truffer, Ted A. Scambos, and Erin C. Pettit
The Cryosphere, 16, 397–417, https://doi.org/10.5194/tc-16-397-2022, https://doi.org/10.5194/tc-16-397-2022, 2022
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Thwaites Glacier has the potential to significantly raise Antarctica's contribution to global sea-level rise by the end of this century. Here, we use satellite measurements of surface elevation to show that its floating part is close to losing contact with an underwater ridge that currently acts to stabilize. We then use computer models of ice flow to simulate the predicted unpinning, which show that accelerated ice discharge into the ocean follows the breakup of the floating part.
Carolyn Branecky Begeman, Xylar Asay-Davis, and Luke Van Roekel
The Cryosphere, 16, 277–295, https://doi.org/10.5194/tc-16-277-2022, https://doi.org/10.5194/tc-16-277-2022, 2022
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This study uses ocean modeling at ultra-high resolution to study the small-scale ocean mixing that controls ice-shelf melting. It offers some insights into the relationship between ice-shelf melting and ocean temperature far from the ice base, which may help us project how fast ice will melt when ocean waters entering the cavity warm. This study adds to a growing body of research that indicates we need a more sophisticated treatment of ice-shelf melting in coarse-resolution ocean models.
Weiran Li, Stef Lhermitte, and Paco López-Dekker
The Cryosphere, 15, 5309–5322, https://doi.org/10.5194/tc-15-5309-2021, https://doi.org/10.5194/tc-15-5309-2021, 2021
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Surface meltwater lakes have been observed on several Antarctic ice shelves in field studies and optical images. Meltwater lakes can drain and refreeze, increasing the fragility of the ice shelves. The combination of synthetic aperture radar (SAR) backscatter and interferometric information (InSAR) can provide the cryosphere community with the possibility to continuously assess the dynamics of the meltwater lakes, potentially helping to facilitate the study of ice shelves in a changing climate.
Karen E. Alley, Christian T. Wild, Adrian Luckman, Ted A. Scambos, Martin Truffer, Erin C. Pettit, Atsuhiro Muto, Bruce Wallin, Marin Klinger, Tyler Sutterley, Sarah F. Child, Cyrus Hulen, Jan T. M. Lenaerts, Michelle Maclennan, Eric Keenan, and Devon Dunmire
The Cryosphere, 15, 5187–5203, https://doi.org/10.5194/tc-15-5187-2021, https://doi.org/10.5194/tc-15-5187-2021, 2021
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We present a 20-year, satellite-based record of velocity and thickness change on the Thwaites Eastern Ice Shelf (TEIS), the largest remaining floating extension of Thwaites Glacier (TG). TG holds the single greatest control on sea-level rise over the next few centuries, so it is important to understand changes on the TEIS, which controls much of TG's flow into the ocean. Our results suggest that the TEIS is progressively destabilizing and is likely to disintegrate over the next few decades.
Holly Still and Christina Hulbe
The Cryosphere, 15, 2647–2665, https://doi.org/10.5194/tc-15-2647-2021, https://doi.org/10.5194/tc-15-2647-2021, 2021
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Pinning points, locations where floating ice shelves run aground, modify ice flow and thickness. We use a model to quantify the Ross Ice Shelf and tributary ice stream response to a group of pinning points. Ice stream sensitivity to pinning points is conditioned by basal drag, and thus basal properties, upstream of the grounding line. Without the pinning points, a redistribution of resistive stresses supports faster flow and increased mass flux but with a negligible change in total ice volume.
Coen Hofstede, Sebastian Beyer, Hugh Corr, Olaf Eisen, Tore Hattermann, Veit Helm, Niklas Neckel, Emma C. Smith, Daniel Steinhage, Ole Zeising, and Angelika Humbert
The Cryosphere, 15, 1517–1535, https://doi.org/10.5194/tc-15-1517-2021, https://doi.org/10.5194/tc-15-1517-2021, 2021
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Support Force Glacier rapidly flows into Filcher Ice Shelf of Antarctica. As we know little about this glacier and its subglacial drainage, we used seismic energy to map the transition area from grounded to floating ice where a drainage channel enters the ocean cavity. Soft sediments close to the grounding line are probably transported by this drainage channel. The constant ice thickness over the steeply dipping seabed of the ocean cavity suggests a stable transition and little basal melting.
Alison F. Banwell, Rajashree Tri Datta, Rebecca L. Dell, Mahsa Moussavi, Ludovic Brucker, Ghislain Picard, Christopher A. Shuman, and Laura A. Stevens
The Cryosphere, 15, 909–925, https://doi.org/10.5194/tc-15-909-2021, https://doi.org/10.5194/tc-15-909-2021, 2021
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Ice shelves are thick floating layers of glacier ice extending from the glaciers on land that buttress much of the Antarctic Ice Sheet and help to protect it from losing ice to the ocean. However, the stability of ice shelves is vulnerable to meltwater lakes that form on their surfaces during the summer. This study focuses on the northern George VI Ice Shelf on the western side of the AP, which had an exceptionally long and extensive melt season in 2019/2020 compared to the previous 31 seasons.
Suzanne Bevan, Adrian Luckman, Harry Hendon, and Guomin Wang
The Cryosphere, 14, 3551–3564, https://doi.org/10.5194/tc-14-3551-2020, https://doi.org/10.5194/tc-14-3551-2020, 2020
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In February 2020, along with record-breaking high temperatures in the region, satellite images showed that the surface of the largest remaining ice shelf on the Antarctic Peninsula was experiencing a lot of melt. Using archived satellite data we show that this melt was greater than any in the past 40 years. The extreme melt followed unusual weather patterns further north, highlighting the importance of long-range links between the tropics and high latitudes and the impact on ice-shelf stability.
Tong Zhang, Stephen F. Price, Matthew J. Hoffman, Mauro Perego, and Xylar Asay-Davis
The Cryosphere, 14, 3407–3424, https://doi.org/10.5194/tc-14-3407-2020, https://doi.org/10.5194/tc-14-3407-2020, 2020
Nicolas C. Jourdain, Xylar Asay-Davis, Tore Hattermann, Fiammetta Straneo, Hélène Seroussi, Christopher M. Little, and Sophie Nowicki
The Cryosphere, 14, 3111–3134, https://doi.org/10.5194/tc-14-3111-2020, https://doi.org/10.5194/tc-14-3111-2020, 2020
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To predict the future Antarctic contribution to sea level rise, we need to use ice sheet models. The Ice Sheet Model Intercomparison Project for AR6 (ISMIP6) builds an ensemble of ice sheet projections constrained by atmosphere and ocean projections from the 6th Coupled Model Intercomparison Project (CMIP6). In this work, we present and assess a method to derive ice shelf basal melting in ISMIP6 from the CMIP6 ocean outputs, and we give examples of projected melt rates.
Rebecca Dell, Neil Arnold, Ian Willis, Alison Banwell, Andrew Williamson, Hamish Pritchard, and Andrew Orr
The Cryosphere, 14, 2313–2330, https://doi.org/10.5194/tc-14-2313-2020, https://doi.org/10.5194/tc-14-2313-2020, 2020
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A semi-automated method is developed from pre-existing work to track surface water bodies across Antarctic ice shelves over time, using data from Sentinel-2 and Landsat 8. This method is applied to the Nivlisen Ice Shelf for the 2016–2017 melt season. The results reveal two large linear meltwater systems, which hold 63 % of the peak total surface meltwater volume on 26 January 2017. These meltwater systems migrate towards the ice shelf front as the melt season progresses.
Bradley Paul Lipovsky
The Cryosphere, 14, 1673–1683, https://doi.org/10.5194/tc-14-1673-2020, https://doi.org/10.5194/tc-14-1673-2020, 2020
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Ice shelves promote the stability of marine ice sheets and therefore reduce the ice sheet contribution to sea level rise. Ice shelf rifts are through-cutting fractures that jeopardize this stabilizing tendency. Here, I carry out the first-ever 3D modeling of ice shelf rifts. I find that the overall ice shelf geometry – particularly the ice shelf margins – alters rift stability. This work paves the way to a more realistic depiction of rifting in ice sheet models.
Wei Wei, Donald D. Blankenship, Jamin S. Greenbaum, Noel Gourmelen, Christine F. Dow, Thomas G. Richter, Chad A. Greene, Duncan A. Young, SangHoon Lee, Tae-Wan Kim, Won Sang Lee, and Karen M. Assmann
The Cryosphere, 14, 1399–1408, https://doi.org/10.5194/tc-14-1399-2020, https://doi.org/10.5194/tc-14-1399-2020, 2020
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Getz Ice Shelf is the largest meltwater source from Antarctica of the Southern Ocean. This study compares the relative importance of the meltwater production of Getz from both ocean and subglacial sources. We show that basal melt rates are elevated where bathymetric troughs provide pathways for warm Circumpolar Deep Water to enter the Getz Ice Shelf cavity. In particular, we find that subshelf melting is enhanced where subglacially discharged fresh water flows across the grounding line.
Christian T. Wild, Oliver J. Marsh, and Wolfgang Rack
The Cryosphere, 13, 3171–3191, https://doi.org/10.5194/tc-13-3171-2019, https://doi.org/10.5194/tc-13-3171-2019, 2019
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In Antarctica, ocean tides control the motion of ice sheets near the coastline as well as melt rates underneath the floating ice. By combining the spatial advantage of rare but highly accurate satellite images with the temporal advantage of tide-prediction models, vertical displacement of floating ice due to ocean tides can now be predicted accurately. This allows the detailed study of ice-flow dynamics in areas that matter the most to the stability of Antarctica's ice sheets.
David E. Shean, Ian R. Joughin, Pierre Dutrieux, Benjamin E. Smith, and Etienne Berthier
The Cryosphere, 13, 2633–2656, https://doi.org/10.5194/tc-13-2633-2019, https://doi.org/10.5194/tc-13-2633-2019, 2019
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We produced an 8-year, high-resolution DEM record for Pine Island Glacier (PIG), a site of substantial Antarctic mass loss in recent decades. We developed methods to study the spatiotemporal evolution of ice shelf basal melting, which is responsible for ~ 60 % of PIG mass loss. We present shelf-wide basal melt rates and document relative melt rates for kilometer-scale basal channels and keels, offering new indirect observations of ice–ocean interaction beneath a vulnerable ice shelf.
Katrin Lindbäck, Geir Moholdt, Keith W. Nicholls, Tore Hattermann, Bhanu Pratap, Meloth Thamban, and Kenichi Matsuoka
The Cryosphere, 13, 2579–2595, https://doi.org/10.5194/tc-13-2579-2019, https://doi.org/10.5194/tc-13-2579-2019, 2019
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In this study, we used a ground-penetrating radar technique to measure melting at high precision under Nivlisen, an ice shelf in central Dronning Maud Land, East Antarctica. We found that summer-warmed ocean surface waters can increase melting close to the ice shelf front. Our study shows the use of and need for measurements in the field to monitor Antarctica's coastal margins; these detailed variations in basal melting are not captured in satellite data but are vital to predict future changes.
Dominic A. Hodgson, Tom A. Jordan, Jan De Rydt, Peter T. Fretwell, Samuel A. Seddon, David Becker, Kelly A. Hogan, Andrew M. Smith, and David G. Vaughan
The Cryosphere, 13, 545–556, https://doi.org/10.5194/tc-13-545-2019, https://doi.org/10.5194/tc-13-545-2019, 2019
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The Brunt Ice Shelf in Antarctica is home to Halley VIa, the latest in a series of six British research stations that have occupied the ice shelf since 1956. A recent rapid growth of rifts in the Brunt Ice Shelf signals the onset of its largest calving event since records began. Here we consider whether this calving event will lead to a new steady state for the ice shelf or an unpinning from the bed, which could predispose it to accelerated flow or collapse.
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Short summary
We use a numerical model to simulate the flow of a simplified, buttressed Antarctic-type outlet glacier with an attached ice shelf. We find that after a few years of perturbation such a glacier responds much stronger to melting under the ice-shelf shear margins than to melting in the central fast streaming part of the ice shelf. This study explains the underlying physical mechanism which might gain importance in the future if melt rates under the Antarctic ice shelves continue to increase.
We use a numerical model to simulate the flow of a simplified, buttressed Antarctic-type outlet...
