Articles | Volume 12, issue 9
The Cryosphere, 12, 2831–2854, 2018
https://doi.org/10.5194/tc-12-2831-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The Cryosphere, 12, 2831–2854, 2018
https://doi.org/10.5194/tc-12-2831-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
05 Sep 2018
Research article
| 05 Sep 2018
A constraint upon the basal water distribution and thermal state of the Greenland Ice Sheet from radar bed echoes
Thomas M. Jordan et al.
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Michael A. Cooper, Thomas M. Jordan, Dustin M. Schroeder, Martin J. Siegert, Christopher N. Williams, and Jonathan L. Bamber
The Cryosphere, 13, 3093–3115, https://doi.org/10.5194/tc-13-3093-2019, https://doi.org/10.5194/tc-13-3093-2019, 2019
Thomas M. Jordan, Michael A. Cooper, Dustin M. Schroeder, Christopher N. Williams, John D. Paden, Martin J. Siegert, and Jonathan L. Bamber
The Cryosphere, 11, 1247–1264, https://doi.org/10.5194/tc-11-1247-2017, https://doi.org/10.5194/tc-11-1247-2017, 2017
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Using radio-echo sounding data from northern Greenland, we demonstrate that subglacial roughness exhibits self-affine (fractal) scaling behaviour. This enables us to assess topographic control upon the bed-echo waveform, and explain the spatial distribution of the degree of scattering (specular and diffuse reflections). Via comparison with a prediction for the basal thermal state (thawed and frozen regions of the bed) we discuss the consequences of our study for basal water discrimination.
Christopher N. Williams, Stephen L. Cornford, Thomas M. Jordan, Julian A. Dowdeswell, Martin J. Siegert, Christopher D. Clark, Darrel A. Swift, Andrew Sole, Ian Fenty, and Jonathan L. Bamber
The Cryosphere, 11, 363–380, https://doi.org/10.5194/tc-11-363-2017, https://doi.org/10.5194/tc-11-363-2017, 2017
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Knowledge of ice sheet bed topography and surrounding sea floor bathymetry is integral to the understanding of ice sheet processes. Existing elevation data products for Greenland underestimate fjord bathymetry due to sparse data availability. We present a new method to create physically based synthetic fjord bathymetry to fill these gaps, greatly improving on previously available datasets. This will assist in future elevation product development until further observations become available.
T. M. Jordan, J. L. Bamber, C. N. Williams, J. D. Paden, M. J. Siegert, P. Huybrechts, O. Gagliardini, and F. Gillet-Chaulet
The Cryosphere, 10, 1547–1570, https://doi.org/10.5194/tc-10-1547-2016, https://doi.org/10.5194/tc-10-1547-2016, 2016
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Ice penetrating radar enables determination of the basal properties of ice sheets. Existing algorithms assume stationarity in the attenuation rate, which is not justifiable at an ice sheet scale. We introduce the first ice-sheet-wide algorithm for radar attenuation that incorporates spatial variability, using the temperature field from a numerical model as an initial guess. The study is a step toward ice-sheet-wide data products for basal properties and evaluation of model temperature fields.
Michael A. Cooper, Paulina Lewińska, William A. P. Smith, Edwin R. Hancock, Julian A. Dowdeswell, and David M. Rippin
The Cryosphere, 16, 2449–2470, https://doi.org/10.5194/tc-16-2449-2022, https://doi.org/10.5194/tc-16-2449-2022, 2022
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Here we use old photographs gathered several decades ago to expand the temporal record of glacier change in part of East Greenland. This is important because the longer the record of past glacier change, the better we are at predicting future glacier behaviour. Our work also shows that despite all these glaciers retreating, the rate at which they do this varies markedly. It is therefore important to consider outlet glaciers from Greenland individually to take account of this differing behaviour.
Jilu Li, Fernando Rodriguez-Morales, Carl Leuschen, John Paden, Daniel Gomez-Garcia, and Emily Arnold
EGUsphere, https://doi.org/10.5194/egusphere-2022-368, https://doi.org/10.5194/egusphere-2022-368, 2022
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Ice mass loss from Alaskan glaciers is an important contributor to global sea level rise. Snow depth and accumulation on these glaciers are key components to understand and model the process of glacier mass loss. In this paper, we reported the observed seasonal snow depth distribution, developed a method to estimate snow accumulation rate at Mt. Wrangell caldera, and identified transition areas from wet-snow zones to ablation zones by analyzing our radar observations in Alaska in 2018 and 2021.
Lander Van Tricht and Philippe Huybrechts
EGUsphere, https://doi.org/10.5194/egusphere-2022-195, https://doi.org/10.5194/egusphere-2022-195, 2022
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We examine the thermal regime of the Grigoriev ice cap and the Sary-Tor glacier, both located in the Inner Tien Shan in Kyrgyzstan. Our findings are important as the ice dynamics can only be understood and modelled precisely if ice temperature is considered correctly in ice flow models. The calibrated parameters of this study can be used in applications with ice flow models for individual ice masses as well as to optimise more general models for large-scale regional simulations.
William Colgan, Agnes Wansing, Kenneth Mankoff, Mareen Lösing, John Hopper, Keith Louden, Jörg Ebbing, Flemming G. Christiansen, Thomas Ingeman-Nielsen, Lillemor Claesson Liljedahl, Joseph A. MacGregor, Árni Hjartarson, Stefan Bernstein, Nanna B. Karlsson, Sven Fuchs, Juha Hartikainen, Johan Liakka, Robert S. Fausto, Dorthe Dahl-Jensen, Anders Bjørk, Jens-Ove Naslund, Finn Mørk, Yasmina Martos, Niels Balling, Thomas Funck, Kristian K. Kjeldsen, Dorthe Petersen, Ulrik Gregersen, Gregers Dam, Tove Nielsen, Shfaqat A. Khan, and Anja Løkkegaard
Earth Syst. Sci. Data, 14, 2209–2238, https://doi.org/10.5194/essd-14-2209-2022, https://doi.org/10.5194/essd-14-2209-2022, 2022
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We assemble all available geothermal heat flow measurements collected in and around Greenland into a new database. We use this database of point measurements, in combination with other geophysical datasets, to model geothermal heat flow in and around Greenland. Our geothermal heat flow model is generally cooler than previous models of Greenland, especially in southern Greenland. It does not suggest any high geothermal heat flows resulting from Icelandic plume activity over 50 million years ago.
Stephen J. Chuter, Andrew Zammit-Mangion, Jonathan Rougier, Geoffrey Dawson, and Jonathan L. Bamber
The Cryosphere, 16, 1349–1367, https://doi.org/10.5194/tc-16-1349-2022, https://doi.org/10.5194/tc-16-1349-2022, 2022
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We find the Antarctic Peninsula to have a mean mass loss of 19 ± 1.1 Gt yr−1 over the 2003–2019 period, driven predominantly by changes in ice dynamic flow like due to changes in ocean forcing. This long-term record is crucial to ascertaining the region’s present-day contribution to sea level rise, with the understanding of driving processes enabling better future predictions. Our statistical approach enables us to estimate this previously poorly surveyed regions mass balance more accurately.
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.
Steven Franke, Daniela Jansen, Tobias Binder, John D. Paden, Nils Dörr, Tamara A. Gerber, Heinrich Miller, Dorthe Dahl-Jensen, Veit Helm, Daniel Steinhage, Ilka Weikusat, Frank Wilhelms, and Olaf Eisen
Earth Syst. Sci. Data, 14, 763–779, https://doi.org/10.5194/essd-14-763-2022, https://doi.org/10.5194/essd-14-763-2022, 2022
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The Northeast Greenland Ice Stream (NEGIS) is the largest ice stream in Greenland. In order to better understand the past and future dynamics of the NEGIS, we present a high-resolution airborne radar data set (EGRIP-NOR-2018) for the onset region of the NEGIS. The survey area is centered at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP), and radar profiles cover both shear margins and are aligned parallel to several flow lines.
Tian Li, Geoffrey J. Dawson, Stephen J. Chuter, and Jonathan L. Bamber
Earth Syst. Sci. Data, 14, 535–557, https://doi.org/10.5194/essd-14-535-2022, https://doi.org/10.5194/essd-14-535-2022, 2022
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Accurate knowledge of the Antarctic grounding zone is important for mass balance calculation, ice sheet stability assessment, and ice sheet model projections. Here we present the first ICESat-2-derived high-resolution grounding zone product of the Antarctic Ice Sheet, including three important boundaries. This new data product will provide more comprehensive insights into ice sheet instability, which is valuable for both the cryosphere and sea level science communities.
Sam Royston, Rory J. Bingham, and Jonathan L. Bamber
Ocean Sci. Discuss., https://doi.org/10.5194/os-2022-3, https://doi.org/10.5194/os-2022-3, 2022
Revised manuscript under review for OS
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Decadal sea-level variability masks longer-term changes and increases uncertainty in observed trend and acceleration estimates. We use numerical ocean models to determine the magnitude of decadal variability we might expect in sea-level trends at coastal locations around the world, resulting from natural, internal variability. A good proportion of that variability can be replicated from known climate modes, giving projection uncertainty for short- to mid-term regional sea-level trend.
Julie Z. Miller, Riley Culberg, David G. Long, Christopher A. Shuman, Dustin M. Schroeder, and Mary J. Brodzik
The Cryosphere, 16, 103–125, https://doi.org/10.5194/tc-16-103-2022, https://doi.org/10.5194/tc-16-103-2022, 2022
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We use L-band brightness temperature imagery from NASA's Soil Moisture Active Passive (SMAP) satellite to map the extent of perennial firn aquifer and ice slab areas within the Greenland Ice Sheet. As Greenland's climate continues to warm and seasonal surface melting increases in extent, intensity, and duration, quantifying the possible rapid expansion of perennial firn aquifers and ice slab areas has significant implications for understanding the stability of the Greenland Ice Sheet.
Fanny Lehmann, Bramha Dutt Vishwakarma, and Jonathan Bamber
Hydrol. Earth Syst. Sci., 26, 35–54, https://doi.org/10.5194/hess-26-35-2022, https://doi.org/10.5194/hess-26-35-2022, 2022
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Many data sources are available to evaluate components of the water cycle (precipitation, evapotranspiration, runoff, and terrestrial water storage). Despite this variety, it remains unclear how different combinations of datasets satisfy the conservation of mass. We conducted the most comprehensive analysis of water budget closure on a global scale to date. Our results can serve as a basis to select appropriate datasets for regional hydrological studies.
Alexander O. Hager, Matthew J. Hoffman, Stephen F. Price, and Dustin M. Schroeder
The Cryosphere Discuss., https://doi.org/10.5194/tc-2021-338, https://doi.org/10.5194/tc-2021-338, 2021
Revised manuscript under review for TC
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The presence of water beneath glaciers is a control on glacier speed and ocean-caused melting, yet it has been unclear whether sizeable volumes of water can exist beneath Antarctic glaciers, or how this water may flow along the glacier bed. We use computer simulations, supported by observations, to show that enough water exists at the base of Thwaites Glacier, Antarctica, to form "rivers" beneath the glacier. These rivers likely moderate glacier speed and may influence its rate of retreat.
Jonas Van Breedam, Philippe Huybrechts, and Michel Crucifix
Geosci. Model Dev., 14, 6373–6401, https://doi.org/10.5194/gmd-14-6373-2021, https://doi.org/10.5194/gmd-14-6373-2021, 2021
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Ice sheets are an important component of the climate system and interact with the atmosphere through albedo variations and changes in the surface height. On very long timescales, it is impossible to directly couple ice sheet models with climate models and other techniques have to be used. Here we present a novel coupling method between ice sheets and the atmosphere by making use of an emulator to simulate ice sheet–climate interactions for several million years.
Marie G. P. Cavitte, Duncan A. Young, Robert Mulvaney, Catherine Ritz, Jamin S. Greenbaum, Gregory Ng, Scott D. Kempf, Enrica Quartini, Gail R. Muldoon, John Paden, Massimo Frezzotti, Jason L. Roberts, Carly R. Tozer, Dustin M. Schroeder, and Donald D. Blankenship
Earth Syst. Sci. Data, 13, 4759–4777, https://doi.org/10.5194/essd-13-4759-2021, https://doi.org/10.5194/essd-13-4759-2021, 2021
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We present a data set consisting of ice-penetrating-radar internal stratigraphy: 26 internal reflecting horizons that cover the greater Dome C area, East Antarctica, the most extensive IRH data set to date in the region. This data set uses radar surveys collected over the span of 10 years, starting with an airborne international collaboration in 2008 to explore the region, up to the detailed ground-based surveys in support of the European Beyond EPICA – Oldest Ice (BE-OI) project.
Lander Van Tricht, Philippe Huybrechts, Jonas Van Breedam, Alexander Vanhulle, Kristof Van Oost, and Harry Zekollari
The Cryosphere, 15, 4445–4464, https://doi.org/10.5194/tc-15-4445-2021, https://doi.org/10.5194/tc-15-4445-2021, 2021
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We conducted innovative research on the use of drones to determine the surface mass balance (SMB) of two glaciers. Considering appropriate spatial scales, we succeeded in determining the SMB in the ablation area with large accuracy. Consequently, we are convinced that our method and the use of drones to monitor the mass balance of a glacier’s ablation area can be an add-on to stake measurements in order to obtain a broader picture of the heterogeneity of the SMB of glaciers.
Tun Jan Young, Carlos Martín, Poul Christoffersen, Dustin M. Schroeder, Slawek M. Tulaczyk, and Eliza J. Dawson
The Cryosphere, 15, 4117–4133, https://doi.org/10.5194/tc-15-4117-2021, https://doi.org/10.5194/tc-15-4117-2021, 2021
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If the molecules that make up ice are oriented in specific ways, the ice becomes softer and enhances flow. We use radar to measure the orientation of ice molecules in the top 1400 m of the Western Antarctic Ice Sheet Divide. Our results match those from an ice core extracted 10 years ago and conclude that the ice flow has not changed direction for the last 6700 years. Our methods are straightforward and accurate and can be applied in places across ice sheets unsuitable for ice coring.
Joseph A. MacGregor, Michael Studinger, Emily Arnold, Carlton J. Leuschen, Fernando Rodríguez-Morales, and John D. Paden
The Cryosphere, 15, 2569–2574, https://doi.org/10.5194/tc-15-2569-2021, https://doi.org/10.5194/tc-15-2569-2021, 2021
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We combine multiple recent global glacier datasets and extend one of them (GlaThiDa) to evaluate past performance of radar-sounding surveys of the thickness of Earth's temperate glaciers. An empirical envelope for radar performance as a function of center frequency is determined, its limitations are discussed and its relevance to future radar-sounder survey and system designs is considered.
Felipe Napoleoni, Stewart S. R. Jamieson, Neil Ross, Michael J. Bentley, Andrés Rivera, Andrew M. Smith, Martin J. Siegert, Guy J. G. Paxman, Guisella Gacitúa, José A. Uribe, Rodrigo Zamora, Alex M. Brisbourne, and David G. Vaughan
The Cryosphere, 14, 4507–4524, https://doi.org/10.5194/tc-14-4507-2020, https://doi.org/10.5194/tc-14-4507-2020, 2020
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Subglacial water is important for ice sheet dynamics and stability. Despite this, there is a lack of detailed subglacial-water characterisation in West Antarctica (WA). We report 33 new subglacial lakes. Additionally, a new digital elevation model of basal topography was built and used to simulate the subglacial hydrological network in WA. The simulated subglacial hydrological catchments of Pine Island and Thwaites glaciers do not match precisely with their ice surface catchments.
Yoni Verhaegen, Philippe Huybrechts, Oleg Rybak, and Victor V. Popovnin
The Cryosphere, 14, 4039–4061, https://doi.org/10.5194/tc-14-4039-2020, https://doi.org/10.5194/tc-14-4039-2020, 2020
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We use a numerical flow model to simulate the behaviour of the Djankuat Glacier, a WGMS reference glacier situated in the North Caucasus (Republic of Kabardino-Balkaria, Russian Federation), in response to past, present and future climate conditions (1752–2100 CE). In particular, we adapt a more sophisticated and physically based debris model, which has not been previously applied in time-dependent numerical flow line models, to look at the impact of a debris cover on the glacier’s evolution.
Xiangbin Cui, Hafeez Jeofry, Jamin S. Greenbaum, Jingxue Guo, Lin Li, Laura E. Lindzey, Feras A. Habbal, Wei Wei, Duncan A. Young, Neil Ross, Mathieu Morlighem, Lenneke M. Jong, Jason L. Roberts, Donald D. Blankenship, Sun Bo, and Martin J. Siegert
Earth Syst. Sci. Data, 12, 2765–2774, https://doi.org/10.5194/essd-12-2765-2020, https://doi.org/10.5194/essd-12-2765-2020, 2020
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We present a topographic digital elevation model (DEM) for Princess Elizabeth Land (PEL), East Antarctica. The DEM covers an area of approximately 900 000 km2 and was built from radio-echo sounding data collected in four campaigns since 2015. Previously, to generate the Bedmap2 topographic product, PEL’s bed was characterised from low-resolution satellite gravity data across an otherwise large (>200 km wide) data-free zone.
Xavier Fettweis, Stefan Hofer, Uta Krebs-Kanzow, Charles Amory, Teruo Aoki, Constantijn J. Berends, Andreas Born, Jason E. Box, Alison Delhasse, Koji Fujita, Paul Gierz, Heiko Goelzer, Edward Hanna, Akihiro Hashimoto, Philippe Huybrechts, Marie-Luise Kapsch, Michalea D. King, Christoph Kittel, Charlotte Lang, Peter L. Langen, Jan T. M. Lenaerts, Glen E. Liston, Gerrit Lohmann, Sebastian H. Mernild, Uwe Mikolajewicz, Kameswarrao Modali, Ruth H. Mottram, Masashi Niwano, Brice Noël, Jonathan C. Ryan, Amy Smith, Jan Streffing, Marco Tedesco, Willem Jan van de Berg, Michiel van den Broeke, Roderik S. W. van de Wal, Leo van Kampenhout, David Wilton, Bert Wouters, Florian Ziemen, and Tobias Zolles
The Cryosphere, 14, 3935–3958, https://doi.org/10.5194/tc-14-3935-2020, https://doi.org/10.5194/tc-14-3935-2020, 2020
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We evaluated simulated Greenland Ice Sheet surface mass balance from 5 kinds of models. While the most complex (but expensive to compute) models remain the best, the faster/simpler models also compare reliably with observations and have biases of the same order as the regional models. Discrepancies in the trend over 2000–2012, however, suggest that large uncertainties remain in the modelled future SMB changes as they are highly impacted by the meltwater runoff biases over the current climate.
Jonas Van Breedam, Heiko Goelzer, and Philippe Huybrechts
Earth Syst. Dynam., 11, 953–976, https://doi.org/10.5194/esd-11-953-2020, https://doi.org/10.5194/esd-11-953-2020, 2020
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We made projections of global mean sea-level change during the next 10 000 years for a range in climate forcing scenarios ranging from a peak in carbon dioxide concentrations in the next decades to burning most of the available carbon reserves over the next 2 centuries. We find that global mean sea level will rise between 9 and 37 m, depending on the emission of greenhouse gases. In this study, we investigated the long-term consequence of climate change for sea-level rise.
Tian Li, Geoffrey J. Dawson, Stephen J. Chuter, and Jonathan L. Bamber
The Cryosphere, 14, 3629–3643, https://doi.org/10.5194/tc-14-3629-2020, https://doi.org/10.5194/tc-14-3629-2020, 2020
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Accurate knowledge of the Antarctic grounding zone is critical for the understanding of ice sheet instability and the evaluation of mass balance. We present a new, fully automated method to map the grounding zone from ICESat-2 laser altimetry. Our results of Larsen C Ice Shelf demonstrate the efficiency, density, and high spatial accuracy with which ICESat-2 can image complex grounding zones.
Heiko Goelzer, Sophie Nowicki, Anthony Payne, Eric Larour, Helene Seroussi, William H. Lipscomb, Jonathan Gregory, Ayako Abe-Ouchi, Andrew Shepherd, Erika Simon, Cécile Agosta, Patrick Alexander, Andy Aschwanden, Alice Barthel, Reinhard Calov, Christopher Chambers, Youngmin Choi, Joshua Cuzzone, Christophe Dumas, Tamsin Edwards, Denis Felikson, Xavier Fettweis, Nicholas R. Golledge, Ralf Greve, Angelika Humbert, Philippe Huybrechts, Sebastien Le clec'h, Victoria Lee, Gunter Leguy, Chris Little, Daniel P. Lowry, Mathieu Morlighem, Isabel Nias, Aurelien Quiquet, Martin Rückamp, Nicole-Jeanne Schlegel, Donald A. Slater, Robin S. Smith, Fiamma Straneo, Lev Tarasov, Roderik van de Wal, and Michiel van den Broeke
The Cryosphere, 14, 3071–3096, https://doi.org/10.5194/tc-14-3071-2020, https://doi.org/10.5194/tc-14-3071-2020, 2020
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In this paper we use a large ensemble of Greenland ice sheet models forced by six different global climate models to project ice sheet changes and sea-level rise contributions over the 21st century.
The results for two different greenhouse gas concentration scenarios indicate that the Greenland ice sheet will continue to lose mass until 2100, with contributions to sea-level rise of 90 ± 50 mm and 32 ± 17 mm for the high (RCP8.5) and low (RCP2.6) scenario, respectively.
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.
Tom A. Jordan, David Porter, Kirsty Tinto, Romain Millan, Atsuhiro Muto, Kelly Hogan, Robert D. Larter, Alastair G. C. Graham, and John D. Paden
The Cryosphere, 14, 2869–2882, https://doi.org/10.5194/tc-14-2869-2020, https://doi.org/10.5194/tc-14-2869-2020, 2020
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Linking ocean and ice sheet processes allows prediction of sea level change. Ice shelves form a floating buffer between the ice–ocean systems, but the water depth beneath is often a mystery, leaving a critical blind spot in our understanding of how these systems interact. Here, we use airborne measurements of gravity to reveal the bathymetry under the ice shelves flanking the rapidly changing Thwaites Glacier and adjacent glacier systems, providing new insights and data for future models.
Neil Ross, Hugh Corr, and Martin Siegert
The Cryosphere, 14, 2103–2114, https://doi.org/10.5194/tc-14-2103-2020, https://doi.org/10.5194/tc-14-2103-2020, 2020
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Using airborne ice-penetrating radar we investigated the physical properties and structure of the West Antarctic Ice Sheet. Ice deep beneath the Institute Ice Stream has prominent layers with physical properties distinct from those around them and which are heavily folded like geological layers. In turn, these folds influence the present-day flow of the ice sheet, with implications for how computer models are used to simulate ice sheet flow and behaviour in a warming world.
Geoffrey J. Dawson and Jonathan L. Bamber
The Cryosphere, 14, 2071–2086, https://doi.org/10.5194/tc-14-2071-2020, https://doi.org/10.5194/tc-14-2071-2020, 2020
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The grounding zone is where grounded ice begins to float and is the boundary at which the ocean has the most significant influence on the inland ice sheet. Here, we present the results of mapping the grounding zone of Antarctic ice shelves from CryoSat-2 radar altimetry. We found good agreement with previous methods that mapped the grounding zone. We also managed to map areas of Support Force Glacier and the Doake Ice Rumples (Filchner–Ronne Ice Shelf), which were previously incompletely mapped.
Marco Meloni, Jerome Bouffard, Tommaso Parrinello, Geoffrey Dawson, Florent Garnier, Veit Helm, Alessandro Di Bella, Stefan Hendricks, Robert Ricker, Erica Webb, Ben Wright, Karina Nielsen, Sanggyun Lee, Marcello Passaro, Michele Scagliola, Sebastian Bjerregaard Simonsen, Louise Sandberg Sørensen, David Brockley, Steven Baker, Sara Fleury, Jonathan Bamber, Luca Maestri, Henriette Skourup, René Forsberg, and Loretta Mizzi
The Cryosphere, 14, 1889–1907, https://doi.org/10.5194/tc-14-1889-2020, https://doi.org/10.5194/tc-14-1889-2020, 2020
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This manuscript aims to describe the evolutions which have been implemented in the new CryoSat Ice processing chain Baseline-D and the validation activities carried out in different domains such as sea ice, land ice and hydrology.
This new CryoSat processing Baseline-D will maximise the uptake and use of CryoSat data by scientific users since it offers improved capability for monitoring the complex and multiscale changes over the cryosphere.
Anders Levermann, Ricarda Winkelmann, Torsten Albrecht, Heiko Goelzer, Nicholas R. Golledge, Ralf Greve, Philippe Huybrechts, Jim Jordan, Gunter Leguy, Daniel Martin, Mathieu Morlighem, Frank Pattyn, David Pollard, Aurelien Quiquet, Christian Rodehacke, Helene Seroussi, Johannes Sutter, Tong Zhang, Jonas Van Breedam, Reinhard Calov, Robert DeConto, Christophe Dumas, Julius Garbe, G. Hilmar Gudmundsson, Matthew J. Hoffman, Angelika Humbert, Thomas Kleiner, William H. Lipscomb, Malte Meinshausen, Esmond Ng, Sophie M. J. Nowicki, Mauro Perego, Stephen F. Price, Fuyuki Saito, Nicole-Jeanne Schlegel, Sainan Sun, and Roderik S. W. van de Wal
Earth Syst. Dynam., 11, 35–76, https://doi.org/10.5194/esd-11-35-2020, https://doi.org/10.5194/esd-11-35-2020, 2020
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We provide an estimate of the future sea level contribution of Antarctica from basal ice shelf melting up to the year 2100. The full uncertainty range in the warming-related forcing of basal melt is estimated and applied to 16 state-of-the-art ice sheet models using a linear response theory approach. The sea level contribution we obtain is very likely below 61 cm under unmitigated climate change until 2100 (RCP8.5) and very likely below 40 cm if the Paris Climate Agreement is kept.
Michael A. Cooper, Thomas M. Jordan, Dustin M. Schroeder, Martin J. Siegert, Christopher N. Williams, and Jonathan L. Bamber
The Cryosphere, 13, 3093–3115, https://doi.org/10.5194/tc-13-3093-2019, https://doi.org/10.5194/tc-13-3093-2019, 2019
Hélène Seroussi, Sophie Nowicki, Erika Simon, Ayako Abe-Ouchi, Torsten Albrecht, Julien Brondex, Stephen Cornford, Christophe Dumas, Fabien Gillet-Chaulet, Heiko Goelzer, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Thomas Kleiner, Eric Larour, Gunter Leguy, William H. Lipscomb, Daniel Lowry, Matthias Mengel, Mathieu Morlighem, Frank Pattyn, Anthony J. Payne, David Pollard, Stephen F. Price, Aurélien Quiquet, Thomas J. Reerink, Ronja Reese, Christian B. Rodehacke, Nicole-Jeanne Schlegel, Andrew Shepherd, Sainan Sun, Johannes Sutter, Jonas Van Breedam, Roderik S. W. van de Wal, Ricarda Winkelmann, and Tong Zhang
The Cryosphere, 13, 1441–1471, https://doi.org/10.5194/tc-13-1441-2019, https://doi.org/10.5194/tc-13-1441-2019, 2019
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We compare a wide range of Antarctic ice sheet simulations with varying initialization techniques and model parameters to understand the role they play on the projected evolution of this ice sheet under simple scenarios. Results are improved compared to previous assessments and show that continued improvements in the representation of the floating ice around Antarctica are critical to reduce the uncertainty in the future ice sheet contribution to sea level rise.
Andres Payo, Bismarck Jigena Antelo, Martin Hurst, Monica Palaseanu-Lovejoy, Chris Williams, Gareth Jenkins, Kathryn Lee, David Favis-Mortlock, Andrew Barkwith, and Michael A. Ellis
Geosci. Model Dev., 11, 4317–4337, https://doi.org/10.5194/gmd-11-4317-2018, https://doi.org/10.5194/gmd-11-4317-2018, 2018
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We describe a new algorithm that automatically delineates the cliff top and toe of a cliffed coastline from a digital elevation model (DEM). The algorithm builds upon existing methods but is specifically designed to resolve very irregular planform coastlines with many bays and capes, such as parts of the coastline of Great Britain.
Jilu Li, Jose A. Vélez González, Carl Leuschen, Ayyangar Harish, Prasad Gogineni, Maurine Montagnat, Ilka Weikusat, Fernando Rodriguez-Morales, and John Paden
The Cryosphere, 12, 2689–2705, https://doi.org/10.5194/tc-12-2689-2018, https://doi.org/10.5194/tc-12-2689-2018, 2018
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Ice properties inferred from multi-polarization measurements can provide insight into ice strain, viscosity, and ice flow. The Center for Remote Sensing of Ice Sheets used a ground-based radar for multi-channel and multi-polarization measurements at the NEEM site. This paper describes the radar system, antenna configurations, data collection, and processing and analysis of this data set. Comparisons between the radar observations, simulations, and ice core fabric data are in very good agreement.
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.
Hafeez Jeofry, Neil Ross, Hugh F. J. Corr, Jilu Li, Mathieu Morlighem, Prasad Gogineni, and Martin J. Siegert
Earth Syst. Sci. Data, 10, 711–725, https://doi.org/10.5194/essd-10-711-2018, https://doi.org/10.5194/essd-10-711-2018, 2018
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Accurately characterizing the complexities of the ice-sheet dynamic specifically close to the grounding line across the Weddell Sea (WS) sector in the ice-sheet models provides challenges to the scientific community. Our main objective is to comprehend these complexities, adding accuracy to the projection of future ice-sheet dynamics. Therefore, we have developed a new bed elevation digital elevation model across the WS sector, which will be of value to ice-sheet modelling experiments.
Ingo Sasgen, Alba Martín-Español, Alexander Horvath, Volker Klemann, Elizabeth J. Petrie, Bert Wouters, Martin Horwath, Roland Pail, Jonathan L. Bamber, Peter J. Clarke, Hannes Konrad, Terry Wilson, and Mark R. Drinkwater
Earth Syst. Sci. Data, 10, 493–523, https://doi.org/10.5194/essd-10-493-2018, https://doi.org/10.5194/essd-10-493-2018, 2018
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We present a collection of data sets, consisting of surface-elevation rates for Antarctic ice sheet from a combination of Envisat and ICESat, bedrock uplift rates for 118 GPS sites in Antarctica, and optimally filtered GRACE gravity field rates. We provide viscoelastic response functions to a disc load forcing for Earth structures present in East and West Antarctica. This data collection enables a joint inversion for present-day ice-mass changes and glacial isostatic adjustment in Antarctica.
Ron Kwok, Nathan T. Kurtz, Ludovic Brucker, Alvaro Ivanoff, Thomas Newman, Sinead L. Farrell, Joshua King, Stephen Howell, Melinda A. Webster, John Paden, Carl Leuschen, Joseph A. MacGregor, Jacqueline Richter-Menge, Jeremy Harbeck, and Mark Tschudi
The Cryosphere, 11, 2571–2593, https://doi.org/10.5194/tc-11-2571-2017, https://doi.org/10.5194/tc-11-2571-2017, 2017
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Since 2009, the ultra-wideband snow radar on Operation IceBridge has acquired data in annual campaigns conducted during the Arctic and Antarctic springs. Existing snow depth retrieval algorithms differ in the way the air–snow and snow–ice interfaces are detected and localized in the radar returns and in how the system limitations are addressed. Here, we assess five retrieval algorithms by comparisons with field measurements, ground-based campaigns, and analyzed fields of snow depth.
Andrew J. Tedstone, Jonathan L. Bamber, Joseph M. Cook, Christopher J. Williamson, Xavier Fettweis, Andrew J. Hodson, and Martyn Tranter
The Cryosphere, 11, 2491–2506, https://doi.org/10.5194/tc-11-2491-2017, https://doi.org/10.5194/tc-11-2491-2017, 2017
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The bare ice albedo of the south-west Greenland ice sheet varies dramatically between years. The reasons are unclear but likely involve darkening by inorganic particulates, cryoconite and ice algae. We use satellite imagery to examine dark ice dynamics and climate model outputs to find likely climatological controls. Outcropping particulates can explain the spatial extent of dark ice, but the darkening itself is likely due to ice algae growth controlled by meltwater and light availability.
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.
Thomas M. Jordan, Michael A. Cooper, Dustin M. Schroeder, Christopher N. Williams, John D. Paden, Martin J. Siegert, and Jonathan L. Bamber
The Cryosphere, 11, 1247–1264, https://doi.org/10.5194/tc-11-1247-2017, https://doi.org/10.5194/tc-11-1247-2017, 2017
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Using radio-echo sounding data from northern Greenland, we demonstrate that subglacial roughness exhibits self-affine (fractal) scaling behaviour. This enables us to assess topographic control upon the bed-echo waveform, and explain the spatial distribution of the degree of scattering (specular and diffuse reflections). Via comparison with a prediction for the basal thermal state (thawed and frozen regions of the bed) we discuss the consequences of our study for basal water discrimination.
Felicity S. Graham, Jason L. Roberts, Ben K. Galton-Fenzi, Duncan Young, Donald Blankenship, and Martin J. Siegert
Earth Syst. Sci. Data, 9, 267–279, https://doi.org/10.5194/essd-9-267-2017, https://doi.org/10.5194/essd-9-267-2017, 2017
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Antarctic bed topography datasets are interpolated onto low-resolution grids because our observed topography data are sparsely sampled. This has implications for ice-sheet model simulations, especially in regions prone to instability, such as grounding lines, where detailed knowledge of the topography is required. Here, we constructed a high-resolution synthetic bed elevation dataset using observed covariance properties to assess the dependence of simulated ice-sheet dynamics on grid resolution.
Harry Zekollari, Philippe Huybrechts, Brice Noël, Willem Jan van de Berg, and Michiel R. van den Broeke
The Cryosphere, 11, 805–825, https://doi.org/10.5194/tc-11-805-2017, https://doi.org/10.5194/tc-11-805-2017, 2017
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In this study the dynamics of the world’s northernmost ice cap are investigated with a 3-D ice flow model. Under 1961–1990 climatic conditions
an ice cap similar to the observed one is obtained, with comparable geometry and surface velocities. The southern part of the ice cap is very unstable,
and under early-21st-century climatic conditions this part of the ice cap fully disappears. In a projected warmer and wetter climate the ice cap will at
first steepen, before eventually disappearing.
Anna Winter, Daniel Steinhage, Emily J. Arnold, Donald D. Blankenship, Marie G. P. Cavitte, Hugh F. J. Corr, John D. Paden, Stefano Urbini, Duncan A. Young, and Olaf Eisen
The Cryosphere, 11, 653–668, https://doi.org/10.5194/tc-11-653-2017, https://doi.org/10.5194/tc-11-653-2017, 2017
Christopher N. Williams, Stephen L. Cornford, Thomas M. Jordan, Julian A. Dowdeswell, Martin J. Siegert, Christopher D. Clark, Darrel A. Swift, Andrew Sole, Ian Fenty, and Jonathan L. Bamber
The Cryosphere, 11, 363–380, https://doi.org/10.5194/tc-11-363-2017, https://doi.org/10.5194/tc-11-363-2017, 2017
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Knowledge of ice sheet bed topography and surrounding sea floor bathymetry is integral to the understanding of ice sheet processes. Existing elevation data products for Greenland underestimate fjord bathymetry due to sparse data availability. We present a new method to create physically based synthetic fjord bathymetry to fill these gaps, greatly improving on previously available datasets. This will assist in future elevation product development until further observations become available.
Heiko Goelzer, Philippe Huybrechts, Marie-France Loutre, and Thierry Fichefet
Clim. Past, 12, 2195–2213, https://doi.org/10.5194/cp-12-2195-2016, https://doi.org/10.5194/cp-12-2195-2016, 2016
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We simulate the climate, ice sheet, and sea-level evolution during the Last Interglacial (~ 130 to 115 kyr BP), the most recent warm period in Earth’s history. Our Earth system model includes components representing the atmosphere, the ocean and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. Our simulation is in good agreement with available data reconstructions and gives important insights into the dominant mechanisms that caused ice sheet changes in the past.
Heiko Goelzer, Philippe Huybrechts, Marie-France Loutre, and Thierry Fichefet
Clim. Past, 12, 1721–1737, https://doi.org/10.5194/cp-12-1721-2016, https://doi.org/10.5194/cp-12-1721-2016, 2016
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We have modelled the climate evolution from 135 to 120 kyr BP with an Earth system model to study the onset of the Last Interglacial warm period. Ice sheet changes and associated freshwater fluxes in both hemispheres constitute an important forcing in the simulations. Freshwater fluxes from the melting Antarctic ice sheet are found to lead to an oceanic cold event in the Southern Ocean as evidenced in some ocean sediment cores, which may be used to constrain the timing of ice sheet retreat.
Lora S. Koenig, Alvaro Ivanoff, Patrick M. Alexander, Joseph A. MacGregor, Xavier Fettweis, Ben Panzer, John D. Paden, Richard R. Forster, Indrani Das, Joesph R. McConnell, Marco Tedesco, Carl Leuschen, and Prasad Gogineni
The Cryosphere, 10, 1739–1752, https://doi.org/10.5194/tc-10-1739-2016, https://doi.org/10.5194/tc-10-1739-2016, 2016
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Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor surface mass balance in order to improve sea-level rise predictions. Here, we quantify the net annual accumulation over the Greenland Ice Sheet, which comprises the largest component of surface mass balance, at a higher spatial resolution than currently available using high-resolution, airborne-radar data.
T. M. Jordan, J. L. Bamber, C. N. Williams, J. D. Paden, M. J. Siegert, P. Huybrechts, O. Gagliardini, and F. Gillet-Chaulet
The Cryosphere, 10, 1547–1570, https://doi.org/10.5194/tc-10-1547-2016, https://doi.org/10.5194/tc-10-1547-2016, 2016
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Ice penetrating radar enables determination of the basal properties of ice sheets. Existing algorithms assume stationarity in the attenuation rate, which is not justifiable at an ice sheet scale. We introduce the first ice-sheet-wide algorithm for radar attenuation that incorporates spatial variability, using the temperature field from a numerical model as an initial guess. The study is a step toward ice-sheet-wide data products for basal properties and evaluation of model temperature fields.
Ioana S. Muresan, Shfaqat A. Khan, Andy Aschwanden, Constantine Khroulev, Tonie Van Dam, Jonathan Bamber, Michiel R. van den Broeke, Bert Wouters, Peter Kuipers Munneke, and Kurt H. Kjær
The Cryosphere, 10, 597–611, https://doi.org/10.5194/tc-10-597-2016, https://doi.org/10.5194/tc-10-597-2016, 2016
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We use a regional 3-D outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) during 1990–2014. The model simulates two major accelerations in 1998 and 2003 that are consistent with observations. We find that most of the JI retreat during the simulated period is driven by the ocean parametrization used, and the glacier's subsequent response, which is largely governed by bed geometry. The study shows progress in modelling the temporal variability of the flow at JI.
Tessa R. Vance, Jason L. Roberts, Andrew D. Moy, Mark A. J. Curran, Carly R. Tozer, Ailie J. E. Gallant, Nerilie J. Abram, Tas D. van Ommen, Duncan A. Young, Cyril Grima, Don D. Blankenship, and Martin J. Siegert
Clim. Past, 12, 595–610, https://doi.org/10.5194/cp-12-595-2016, https://doi.org/10.5194/cp-12-595-2016, 2016
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This study details a systematic approach to finding a new high-resolution East Antarctic ice core site. The study initially outlines seven criteria that a new site must fulfil, encompassing specific accumulation, ice dynamics and atmospheric circulation aspects. We then use numerous techniques including Antarctic surface mass balance syntheses, ground-truthing of satellite data by airborne radar surveys and reanalysis products to pinpoint promising regions.
A. E. Jowett, E. Hanna, F. Ng, P. Huybrechts, and I. Janssens
The Cryosphere Discuss., https://doi.org/10.5194/tcd-9-5327-2015, https://doi.org/10.5194/tcd-9-5327-2015, 2015
Revised manuscript has not been submitted
L. S. Koenig, D. J. Lampkin, L. N. Montgomery, S. L. Hamilton, J. B. Turrin, C. A. Joseph, S. E. Moutsafa, B. Panzer, K. A. Casey, J. D. Paden, C. Leuschen, and P. Gogineni
The Cryosphere, 9, 1333–1342, https://doi.org/10.5194/tc-9-1333-2015, https://doi.org/10.5194/tc-9-1333-2015, 2015
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The Greenland Ice Sheet is storing meltwater through the winter season just below its surface in buried supraglacial lakes. Airborne radar from Operation IceBridge between 2009 and 2012 was used to detect buried lakes, distributed extensively around the margin of the ice sheet. The volume of retained water in the buried lakes is likely insignificant compared to the total mass loss from the ice sheet but has important implications for ice temperatures.
J. J. Fürst, H. Goelzer, and P. Huybrechts
The Cryosphere, 9, 1039–1062, https://doi.org/10.5194/tc-9-1039-2015, https://doi.org/10.5194/tc-9-1039-2015, 2015
P. R. Holland, A. Brisbourne, H. F. J. Corr, D. McGrath, K. Purdon, J. Paden, H. A. Fricker, F. S. Paolo, and A. H. Fleming
The Cryosphere, 9, 1005–1024, https://doi.org/10.5194/tc-9-1005-2015, https://doi.org/10.5194/tc-9-1005-2015, 2015
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Antarctic Peninsula ice shelves have collapsed in recent decades. The surface of Larsen C Ice Shelf is lowering, but the cause of this has not been understood. This study uses eight radar surveys to show that the lowering is caused by both ice loss and a loss of air from the ice shelf's snowpack. At least two different processes are causing the lowering. The stability of Larsen C may be at risk from an ungrounding of Bawden Ice Rise or ice-front retreat past a 'compressive arch' in strain rates.
B. de Boer, A. M. Dolan, J. Bernales, E. Gasson, H. Goelzer, N. R. Golledge, J. Sutter, P. Huybrechts, G. Lohmann, I. Rogozhina, A. Abe-Ouchi, F. Saito, and R. S. W. van de Wal
The Cryosphere, 9, 881–903, https://doi.org/10.5194/tc-9-881-2015, https://doi.org/10.5194/tc-9-881-2015, 2015
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We present results from simulations of the Antarctic ice sheet by means of an intercomparison project with six ice-sheet models. Our results demonstrate the difficulty of all models used here to simulate a significant retreat or re-advance of the East Antarctic ice grounding line. Improved grounding-line physics could be essential for a correct representation of the migration of the grounding line of the Antarctic ice sheet during the Pliocene.
N. Schoen, A. Zammit-Mangion, J. C. Rougier, T. Flament, F. Rémy, S. Luthcke, and J. L. Bamber
The Cryosphere, 9, 805–819, https://doi.org/10.5194/tc-9-805-2015, https://doi.org/10.5194/tc-9-805-2015, 2015
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This paper provides a proof of concept approach for combining multiple observations and inferences to provide rigorous, error-bounded estimates of mass trends and surface processes for the Antarctic ice sheet. Here we apply the method to West Antarctica, using a time-invariant solution by way of proof of concept. Subsequent work will utilise a time evolving approach to the whole ice sheet.
K. C. Rose, N. Ross, T. A. Jordan, R. G. Bingham, H. F. J. Corr, F. Ferraccioli, A. M. Le Brocq, D. M. Rippin, and M. J. Siegert
Earth Surf. Dynam., 3, 139–152, https://doi.org/10.5194/esurf-3-139-2015, https://doi.org/10.5194/esurf-3-139-2015, 2015
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We use ice-penetrating-radar data to identify a laterally continuous, gently sloping topographic block, comprising two surfaces separated by a distinct break in slope, preserved beneath the Institute and Möller ice streams, West Antarctica. We interpret these features as extensive erosion surfaces, showing that ancient (pre-glacial) surfaces can be preserved at low elevations beneath ice sheets. Different erosion regimes (e.g. fluvial and marine) may have formed these surfaces.
R. T. W. L. Hurkmans, J. L. Bamber, C. H. Davis, I. R. Joughin, K. S. Khvorostovsky, B. S. Smith, and N. Schoen
The Cryosphere, 8, 1725–1740, https://doi.org/10.5194/tc-8-1725-2014, https://doi.org/10.5194/tc-8-1725-2014, 2014
M. F. Loutre, T. Fichefet, H. Goosse, P. Huybrechts, H. Goelzer, and E. Capron
Clim. Past, 10, 1541–1565, https://doi.org/10.5194/cp-10-1541-2014, https://doi.org/10.5194/cp-10-1541-2014, 2014
T. Howard, A. K. Pardaens, J. L. Bamber, J. Ridley, G. Spada, R. T. W. L. Hurkmans, J. A. Lowe, and D. Vaughan
Ocean Sci., 10, 473–483, https://doi.org/10.5194/os-10-473-2014, https://doi.org/10.5194/os-10-473-2014, 2014
T. Howard, J. Ridley, A. K. Pardaens, R. T. W. L. Hurkmans, A. J. Payne, R. H. Giesen, J. A. Lowe, J. L. Bamber, T. L. Edwards, and J. Oerlemans
Ocean Sci., 10, 485–500, https://doi.org/10.5194/os-10-485-2014, https://doi.org/10.5194/os-10-485-2014, 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, 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
I. Sasgen, H. Konrad, E. R. Ivins, M. R. Van den Broeke, J. L. Bamber, Z. Martinec, and V. Klemann
The Cryosphere, 7, 1499–1512, https://doi.org/10.5194/tc-7-1499-2013, https://doi.org/10.5194/tc-7-1499-2013, 2013
I. Joughin, S. B. Das, G. E. Flowers, M. D. Behn, R. B. Alley, M. A. King, B. E. Smith, J. L. Bamber, M. R. van den Broeke, and J. H. van Angelen
The Cryosphere, 7, 1185–1192, https://doi.org/10.5194/tc-7-1185-2013, https://doi.org/10.5194/tc-7-1185-2013, 2013
C. L. Vernon, J. L. Bamber, J. E. Box, M. R. van den Broeke, X. Fettweis, E. Hanna, and P. Huybrechts
The Cryosphere, 7, 599–614, https://doi.org/10.5194/tc-7-599-2013, https://doi.org/10.5194/tc-7-599-2013, 2013
J. L. Bamber, J. A. Griggs, R. T. W. L. Hurkmans, J. A. Dowdeswell, S. P. Gogineni, I. Howat, J. Mouginot, J. Paden, S. Palmer, E. Rignot, and D. Steinhage
The Cryosphere, 7, 499–510, https://doi.org/10.5194/tc-7-499-2013, https://doi.org/10.5194/tc-7-499-2013, 2013
P. Fretwell, H. D. Pritchard, D. G. Vaughan, J. L. Bamber, N. E. Barrand, R. Bell, C. Bianchi, R. G. Bingham, D. D. Blankenship, G. Casassa, G. Catania, D. Callens, H. Conway, A. J. Cook, H. F. J. Corr, D. Damaske, V. Damm, F. Ferraccioli, R. Forsberg, S. Fujita, Y. Gim, P. Gogineni, J. A. Griggs, R. C. A. Hindmarsh, P. Holmlund, J. W. Holt, R. W. Jacobel, A. Jenkins, W. Jokat, T. Jordan, E. C. King, J. Kohler, W. Krabill, M. Riger-Kusk, K. A. Langley, G. Leitchenkov, C. Leuschen, B. P. Luyendyk, K. Matsuoka, J. Mouginot, F. O. Nitsche, Y. Nogi, O. A. Nost, S. V. Popov, E. Rignot, D. M. Rippin, A. Rivera, J. Roberts, N. Ross, M. J. Siegert, A. M. Smith, D. Steinhage, M. Studinger, B. Sun, B. K. Tinto, B. C. Welch, D. Wilson, D. A. Young, C. Xiangbin, and A. Zirizzotti
The Cryosphere, 7, 375–393, https://doi.org/10.5194/tc-7-375-2013, https://doi.org/10.5194/tc-7-375-2013, 2013
J. J. Fürst, H. Goelzer, and P. Huybrechts
The Cryosphere, 7, 183–199, https://doi.org/10.5194/tc-7-183-2013, https://doi.org/10.5194/tc-7-183-2013, 2013
M. G. P. Cavitte, D. D. Blankenship, D. A. Young, M. J. Siegert, and E. Le Meur
The Cryosphere Discuss., https://doi.org/10.5194/tcd-7-321-2013, https://doi.org/10.5194/tcd-7-321-2013, 2013
Revised manuscript not accepted
Related subject area
Discipline: Ice sheets | Subject: Greenland
Unravelling the long-term, locally heterogenous response of Greenland glaciers observed in archival photography
Simulating the Holocene deglaciation across a marine-terminating portion of southwestern Greenland in response to marine and atmospheric forcings
Comparison of ice dynamics using full-Stokes and Blatter–Pattyn approximation: application to the Northeast Greenland Ice Stream
Melt probabilities and surface temperature trends on the Greenland ice sheet using a Gaussian mixture model
Modelling the effect of submarine iceberg melting on glacier-adjacent water properties
Multi-decadal retreat of marine-terminating outlet glaciers in northwest and central-west Greenland
Sources of uncertainty in Greenland surface mass balance in the 21st century
Proper orthogonal decomposition of ice velocity identifies drivers of flow variability at Sermeq Kujalleq (Jakobshavn Isbræ)
Brief communication: A roadmap towards credible projections of ice sheet contribution to sea level
Automated detection and analysis of surface calving waves with a terrestrial radar interferometer at the front of Eqip Sermia, Greenland
Generation and fate of basal meltwater during winter, western Greenland Ice Sheet
Modeling the Greenland englacial stratigraphy
Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model
Indication of high basal melting at the EastGRIP drill site on the Northeast Greenland Ice Stream
Brief communication: Reduction in the future Greenland ice sheet surface melt with the help of solar geoengineering
Contrasting regional variability of buried meltwater extent over 2 years across the Greenland Ice Sheet
Sensitivity of the Greenland surface mass and energy balance to uncertainties in key model parameters
Surface melting over the Greenland ice sheet derived from enhanced resolution passive microwave brightness temperatures (1979–2019)
Impact of updated radiative transfer scheme in snow and ice in RACMO2.3p3 on the surface mass and energy budget of the Greenland ice sheet
Winter drainage of surface lakes on the Greenland Ice Sheet from Sentinel-1 SAR imagery
Basal traction mainly dictated by hard-bed physics over grounded regions of Greenland
The GRISLI-LSCE contribution to the Ice Sheet Model Intercomparison Project for phase 6 of the Coupled Model Intercomparison Project (ISMIP6) – Part 1: Projections of the Greenland ice sheet evolution by the end of the 21st century
The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet
Last glacial ice sheet dynamics offshore NE Greenland – a case study from Store Koldewey Trough
Large and irreversible future decline of the Greenland ice sheet
GrSMBMIP: intercomparison of the modelled 1980–2012 surface mass balance over the Greenland Ice Sheet
The firn meltwater Retention Model Intercomparison Project (RetMIP): evaluation of nine firn models at four weather station sites on the Greenland ice sheet
Evaluation of a new snow albedo scheme for the Greenland ice sheet in the Regional Atmospheric Climate Model (RACMO2)
Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS
Intercomparison of surface meltwater routing models for the Greenland ice sheet and influence on subglacial effective pressures
Sensitivity of Greenland ice sheet projections to spatial resolution in higher-order simulations: the Alfred Wegener Institute (AWI) contribution to ISMIP6 Greenland using the Ice-sheet and Sea-level System Model (ISSM)
The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6
Present-day and future Greenland Ice Sheet precipitation frequency from CloudSat observations and the Community Earth System Model
The added value of high resolution in estimating the surface mass balance in southern Greenland
Horizontal ice flow impacts the firn structure of Greenland's percolation zone
Brief communication: CESM2 climate forcing (1950–2014) yields realistic Greenland ice sheet surface mass balance
Unprecedented atmospheric conditions (1948–2019) drive the 2019 exceptional melting season over the Greenland ice sheet
Calving event size measurements and statistics of Eqip Sermia, Greenland, from terrestrial radar interferometry
Brief communication: Evaluation of the near-surface climate in ERA5 over the Greenland Ice Sheet
Algal growth and weathering crust state drive variability in western Greenland Ice Sheet ice albedo
Relating regional and point measurements of accumulation in southwest Greenland
Surface mass balance downscaling through elevation classes in an Earth system model: application to the Greenland ice sheet
Brief communication: Subglacial lake drainage beneath Isunguata Sermia, West Greenland: geomorphic and ice dynamic effects
The surface albedo of the Greenland Ice Sheet between 1982 and 2015 from the CLARA-A2 dataset and its relationship to the ice sheet's surface mass balance
Submarine melt as a potential trigger of the North East Greenland Ice Stream margin retreat during Marine Isotope Stage 3
Firn data compilation reveals widespread decrease of firn air content in western Greenland
Increased Greenland melt triggered by large-scale, year-round cyclonic moisture intrusions
Velocity response of Petermann Glacier, northwest Greenland, to past and future calving events
Seasonal to decadal variability in ice discharge from the Greenland Ice Sheet
A new surface meltwater routing model for use on the Greenland Ice Sheet surface
Michael A. Cooper, Paulina Lewińska, William A. P. Smith, Edwin R. Hancock, Julian A. Dowdeswell, and David M. Rippin
The Cryosphere, 16, 2449–2470, https://doi.org/10.5194/tc-16-2449-2022, https://doi.org/10.5194/tc-16-2449-2022, 2022
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Here we use old photographs gathered several decades ago to expand the temporal record of glacier change in part of East Greenland. This is important because the longer the record of past glacier change, the better we are at predicting future glacier behaviour. Our work also shows that despite all these glaciers retreating, the rate at which they do this varies markedly. It is therefore important to consider outlet glaciers from Greenland individually to take account of this differing behaviour.
Joshua K. Cuzzone, Nicolás E. Young, Mathieu Morlighem, Jason P. Briner, and Nicole-Jeanne Schlegel
The Cryosphere, 16, 2355–2372, https://doi.org/10.5194/tc-16-2355-2022, https://doi.org/10.5194/tc-16-2355-2022, 2022
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We use an ice sheet model to determine what influenced the Greenland Ice Sheet to retreat across a portion of southwestern Greenland during the Holocene (about the last 12 000 years). Our simulations, constrained by observations from geologic markers, show that atmospheric warming and ice melt primarily caused the ice sheet to retreat rapidly across this domain. We find, however, that iceberg calving at the interface where the ice meets the ocean significantly influenced ice mass change.
Martin Rückamp, Thomas Kleiner, and Angelika Humbert
The Cryosphere, 16, 1675–1696, https://doi.org/10.5194/tc-16-1675-2022, https://doi.org/10.5194/tc-16-1675-2022, 2022
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We present a comparative modelling study between the full-Stokes (FS) and Blatter–Pattyn (BP) approximation applied to the Northeast Greenland Ice Stream. Both stress regimes are implemented in one single ice sheet code to eliminate numerical issues. The simulations unveil minor differences in the upper ice stream but become considerable at the grounding line of the 79° North Glacier. Model differences are stronger for a power-law friction than a linear friction law.
Daniel Clarkson, Emma Eastoe, and Amber Leeson
The Cryosphere, 16, 1597–1607, https://doi.org/10.5194/tc-16-1597-2022, https://doi.org/10.5194/tc-16-1597-2022, 2022
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The Greenland ice sheet has seen large amounts of melt in recent years, and accurately modelling temperatures is vital to understand how much of the ice sheet is melting. We estimate the probability of melt from ice surface temperature data to identify which areas of the ice sheet have experienced melt and estimate temperature quantiles. Our results suggest that for large areas of the ice sheet, melt has become more likely over the past 2 decades and high temperatures are also becoming warmer.
Benjamin Joseph Davison, Tom Cowton, Andrew Sole, Finlo Cottier, and Pete Nienow
The Cryosphere, 16, 1181–1196, https://doi.org/10.5194/tc-16-1181-2022, https://doi.org/10.5194/tc-16-1181-2022, 2022
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The ocean is an important driver of Greenland glacier retreat. Icebergs influence ocean temperature in the vicinity of glaciers, which will affect glacier retreat rates, but the effect of icebergs on water temperature is poorly understood. In this study, we use a model to show that icebergs cause large changes to water properties next to Greenland's glaciers, which could influence ocean-driven glacier retreat around Greenland.
Taryn E. Black and Ian Joughin
The Cryosphere, 16, 807–824, https://doi.org/10.5194/tc-16-807-2022, https://doi.org/10.5194/tc-16-807-2022, 2022
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We used satellite images to create a comprehensive record of annual glacier change in northwest Greenland from 1972 through 2021. We found that nearly all glaciers in our study area have retreated and glacier retreat accelerated from around 1996. Comparing these results with climate data, we found that glacier retreat is most sensitive to water runoff and moderately sensitive to ocean temperatures. These can affect glacier fronts in several ways, so no process clearly dominates glacier retreat.
Katharina M. Holube, Tobias Zolles, and Andreas Born
The Cryosphere, 16, 315–331, https://doi.org/10.5194/tc-16-315-2022, https://doi.org/10.5194/tc-16-315-2022, 2022
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We simulated the surface mass balance of the Greenland Ice Sheet in the 21st century by forcing a snow model with the output of many Earth system models and four greenhouse gas emission scenarios. We quantify the contribution to uncertainty in surface mass balance of these two factors and the choice of parameters of the snow model. The results show that the differences between Earth system models are the main source of uncertainty. This effect is localised mostly near the equilibrium line.
David W. Ashmore, Douglas W. F. Mair, Jonathan E. Higham, Stephen Brough, James M. Lea, and Isabel J. Nias
The Cryosphere, 16, 219–236, https://doi.org/10.5194/tc-16-219-2022, https://doi.org/10.5194/tc-16-219-2022, 2022
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In this paper we explore the use of a transferrable and flexible statistical technique to try and untangle the multiple influences on marine-terminating glacier dynamics, as measured from space. We decompose a satellite-derived ice velocity record into ranked sets of static maps and temporal coefficients. We present evidence that the approach can identify velocity variability mainly driven by changes in terminus position and velocity variation mainly driven by subglacial hydrological processes.
Andy Aschwanden, Timothy C. Bartholomaus, Douglas J. Brinkerhoff, and Martin Truffer
The Cryosphere, 15, 5705–5715, https://doi.org/10.5194/tc-15-5705-2021, https://doi.org/10.5194/tc-15-5705-2021, 2021
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Estimating how much ice loss from Greenland and Antarctica will contribute to sea level rise is of critical societal importance. However, our analysis shows that recent efforts are not trustworthy because the models fail at reproducing contemporary ice melt. Here we present a roadmap towards making more credible estimates of ice sheet melt.
Adrien Wehrlé, Martin P. Lüthi, Andrea Walter, Guillaume Jouvet, and Andreas Vieli
The Cryosphere, 15, 5659–5674, https://doi.org/10.5194/tc-15-5659-2021, https://doi.org/10.5194/tc-15-5659-2021, 2021
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We developed a novel automated method for the detection and the quantification of ocean waves generated by glacier calving. This method was applied to data recorded with a terrestrial radar interferometer at Eqip Sermia, Greenland. Results show a high calving activity at the glacier front sector ending in deep water linked with more frequent meltwater plumes. This suggests that rising subglacial meltwater plumes strongly affect glacier calving in deep water, but weakly in shallow water.
Joel Harper, Toby Meierbachtol, Neil Humphrey, Jun Saito, and Aidan Stansberry
The Cryosphere, 15, 5409–5421, https://doi.org/10.5194/tc-15-5409-2021, https://doi.org/10.5194/tc-15-5409-2021, 2021
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We use surface and borehole measurements to investigate the generation and fate of basal meltwater in the ablation zone of western Greenland. The rate of basal meltwater generation at borehole study sites increases by up to 20 % over the winter period. Accommodation of all basal meltwater by expansion of isolated subglacial cavities is implausible. Other sinks for water do not likely balance basal meltwater generation, implying water evacuation through a connected drainage system in winter.
Andreas Born and Alexander Robinson
The Cryosphere, 15, 4539–4556, https://doi.org/10.5194/tc-15-4539-2021, https://doi.org/10.5194/tc-15-4539-2021, 2021
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Ice penetrating radar reflections from the Greenland ice sheet are the best available record of past accumulation and how these layers have been deformed over time by the flow of ice. Direct simulations of this archive hold great promise for improving our models and for uncovering details of ice sheet dynamics that neither models nor data could achieve alone. We present the first three-dimensional ice sheet model that explicitly simulates individual layers of accumulation and how they deform.
Tamara Annina Gerber, Christine Schøtt Hvidberg, Sune Olander Rasmussen, Steven Franke, Giulia Sinnl, Aslak Grinsted, Daniela Jansen, and Dorthe Dahl-Jensen
The Cryosphere, 15, 3655–3679, https://doi.org/10.5194/tc-15-3655-2021, https://doi.org/10.5194/tc-15-3655-2021, 2021
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We simulate the ice flow in the onset region of the Northeast Greenland Ice Stream to determine the source area and past accumulation rates of ice found in the EastGRIP ice core. This information is required to correct for bias in ice-core records introduced by the upstream flow effects. Our results reveal that the increasing accumulation rate with increasing upstream distance is predominantly responsible for the constant annual layer thicknesses observed in the upper 900 m of the ice core.
Ole Zeising and Angelika Humbert
The Cryosphere, 15, 3119–3128, https://doi.org/10.5194/tc-15-3119-2021, https://doi.org/10.5194/tc-15-3119-2021, 2021
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Greenland’s largest ice stream – the Northeast Greenland Ice Stream (NEGIS) – extends far into the interior of the ice sheet. Basal meltwater acts as a lubricant for glaciers and sustains sliding. Hence, observations of basal melt rates are of high interest. We performed two time series of precise ground-based radar measurements in the upstream region of NEGIS and found high melt rates of 0.19 ± 0.04 m per year.
Xavier Fettweis, Stefan Hofer, Roland Séférian, Charles Amory, Alison Delhasse, Sébastien Doutreloup, Christoph Kittel, Charlotte Lang, Joris Van Bever, Florent Veillon, and Peter Irvine
The Cryosphere, 15, 3013–3019, https://doi.org/10.5194/tc-15-3013-2021, https://doi.org/10.5194/tc-15-3013-2021, 2021
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Without any reduction in our greenhouse gas emissions, the Greenland ice sheet surface mass loss can be brought in line with a medium-mitigation emissions scenario by reducing the solar downward flux at the top of the atmosphere by 1.5 %. In addition to reducing global warming, these solar geoengineering measures also dampen the well-known positive melt–albedo feedback over the ice sheet by 6 %. However, only stronger reductions in solar radiation could maintain a stable ice sheet in 2100.
Devon Dunmire, Alison F. Banwell, Nander Wever, Jan T. M. Lenaerts, and Rajashree Tri Datta
The Cryosphere, 15, 2983–3005, https://doi.org/10.5194/tc-15-2983-2021, https://doi.org/10.5194/tc-15-2983-2021, 2021
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Here, we automatically detect buried lakes (meltwater lakes buried below layers of snow) across the Greenland Ice Sheet, providing insight into a poorly studied meltwater feature. For 2018 and 2019, we compare areal extent of buried lakes. We find greater buried lake extent in 2019, especially in northern Greenland, which we attribute to late-summer surface melt and high autumn temperatures. We also provide evidence that buried lakes form via different processes across Greenland.
Tobias Zolles and Andreas Born
The Cryosphere, 15, 2917–2938, https://doi.org/10.5194/tc-15-2917-2021, https://doi.org/10.5194/tc-15-2917-2021, 2021
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We investigate the sensitivity of a glacier surface mass and the energy balance model of the Greenland ice sheet for the cold period of the Last Glacial Maximum (LGM) and the present-day climate. The results show that the model sensitivity changes with climate. While for present-day simulations inclusions of sublimation and hoar formation are of minor importance, they cannot be neglected during the LGM. To simulate the surface mass balance over long timescales, a water vapor scheme is necessary.
Paolo Colosio, Marco Tedesco, Roberto Ranzi, and Xavier Fettweis
The Cryosphere, 15, 2623–2646, https://doi.org/10.5194/tc-15-2623-2021, https://doi.org/10.5194/tc-15-2623-2021, 2021
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We use a new satellite dataset to study the spatiotemporal evolution of surface melting over Greenland at an enhanced resolution of 3.125 km. Using meteorological data and the MAR model, we observe that a dynamic algorithm can best detect surface melting. We found that the melting season is elongating, the melt extent is increasing and that high-resolution data better describe the spatiotemporal evolution of the melting season, which is crucial to improve estimates of sea level rise.
Christiaan T. van Dalum, Willem Jan van de Berg, and Michiel R. van den Broeke
The Cryosphere, 15, 1823–1844, https://doi.org/10.5194/tc-15-1823-2021, https://doi.org/10.5194/tc-15-1823-2021, 2021
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Absorption of solar radiation is often limited to the surface in regional climate models. Therefore, we have implemented a new radiative transfer scheme in the model RACMO2, which allows for internal heating and improves the surface reflectivity. Here, we evaluate its impact on the surface mass and energy budget and (sub)surface temperature, by using observations and the previous model version for the Greenland ice sheet. New results match better with observations and introduce subsurface melt.
Corinne L. Benedek and Ian C. Willis
The Cryosphere, 15, 1587–1606, https://doi.org/10.5194/tc-15-1587-2021, https://doi.org/10.5194/tc-15-1587-2021, 2021
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The surface of the Greenland Ice Sheet contains thousands of surface lakes. These lakes can deliver water through cracks to the ice sheet base and influence the speed of ice flow. Here we look at instances of lakes draining in the middle of winter using the Sentinel-1 radar satellites. Winter-draining lakes can help us understand the mechanisms for lake drainages throughout the year and can point to winter movement of water that will impact our understanding of ice sheet hydrology.
Nathan Maier, Florent Gimbert, Fabien Gillet-Chaulet, and Adrien Gilbert
The Cryosphere, 15, 1435–1451, https://doi.org/10.5194/tc-15-1435-2021, https://doi.org/10.5194/tc-15-1435-2021, 2021
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In Greenland, ice motion and the surface geometry depend on the friction at the bed. We use satellite measurements and modeling to determine how ice speeds and friction are related across the ice sheet. The relationships indicate that ice flowing over bed bumps sets the friction across most of the ice sheet's on-land regions. This result helps simplify and improve our understanding of how ice motion will change in the future.
Aurélien Quiquet and Christophe Dumas
The Cryosphere, 15, 1015–1030, https://doi.org/10.5194/tc-15-1015-2021, https://doi.org/10.5194/tc-15-1015-2021, 2021
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We present here the GRISLI-LSCE contribution to the Ice Sheet Model Intercomparison Project for CMIP6 for Greenland. The project aims to quantify the ice sheet contribution to global sea level rise for the next century. We show an important spread in the simulated Greenland ice loss in the future depending on the climate forcing used. Mass loss is primarily driven by atmospheric warming, while oceanic forcing contributes to a relatively smaller uncertainty in our simulations.
Ian E. McDowell, Neil F. Humphrey, Joel T. Harper, and Toby W. Meierbachtol
The Cryosphere, 15, 897–907, https://doi.org/10.5194/tc-15-897-2021, https://doi.org/10.5194/tc-15-897-2021, 2021
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Ice temperature controls rates of internal deformation and the onset of basal sliding. To identify heat transfer mechanisms and englacial heat sources within Greenland's ablation zone, we examine a 2–3-year continuous temperature record from nine full-depth boreholes. Thermal decay after basal crevasses release heat in the near-basal ice likely produces the observed cooling. Basal crevasses in Greenland can affect the basal ice rheology and indicate a potentially complex basal hydrologic system.
Ingrid Leirvik Olsen, Tom Arne Rydningen, Matthias Forwick, Jan Sverre Laberg, and Katrine Husum
The Cryosphere, 14, 4475–4494, https://doi.org/10.5194/tc-14-4475-2020, https://doi.org/10.5194/tc-14-4475-2020, 2020
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We present marine geoscientific data from Store Koldewey Trough, one of the largest glacial troughs offshore NE Greenland, to reconstruct the ice drainage pathways, ice sheet extent and ice stream dynamics of this sector during the last glacial and deglaciation. The complex landform assemblage in the trough reflects a dynamic retreat with several periods of stabilization and readvances, interrupting the deglaciation. Estimates indicate that the ice front locally retreated between 80–400 m/year.
Jonathan M. Gregory, Steven E. George, and Robin S. Smith
The Cryosphere, 14, 4299–4322, https://doi.org/10.5194/tc-14-4299-2020, https://doi.org/10.5194/tc-14-4299-2020, 2020
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Melting of the Greenland ice sheet as a consequence of global warming could raise global-mean sea level by up to 7 m. We have studied this using a newly developed computer model. With recent climate maintained, sea level would rise by 0.5–2.5 m over many millennia due to Greenland ice loss: the warmer the climate, the greater the sea level rise. Beyond about 3.5 m it would become partially irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed soon enough.
Xavier Fettweis, Stefan Hofer, Uta Krebs-Kanzow, Charles Amory, Teruo Aoki, Constantijn J. Berends, Andreas Born, Jason E. Box, Alison Delhasse, Koji Fujita, Paul Gierz, Heiko Goelzer, Edward Hanna, Akihiro Hashimoto, Philippe Huybrechts, Marie-Luise Kapsch, Michalea D. King, Christoph Kittel, Charlotte Lang, Peter L. Langen, Jan T. M. Lenaerts, Glen E. Liston, Gerrit Lohmann, Sebastian H. Mernild, Uwe Mikolajewicz, Kameswarrao Modali, Ruth H. Mottram, Masashi Niwano, Brice Noël, Jonathan C. Ryan, Amy Smith, Jan Streffing, Marco Tedesco, Willem Jan van de Berg, Michiel van den Broeke, Roderik S. W. van de Wal, Leo van Kampenhout, David Wilton, Bert Wouters, Florian Ziemen, and Tobias Zolles
The Cryosphere, 14, 3935–3958, https://doi.org/10.5194/tc-14-3935-2020, https://doi.org/10.5194/tc-14-3935-2020, 2020
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We evaluated simulated Greenland Ice Sheet surface mass balance from 5 kinds of models. While the most complex (but expensive to compute) models remain the best, the faster/simpler models also compare reliably with observations and have biases of the same order as the regional models. Discrepancies in the trend over 2000–2012, however, suggest that large uncertainties remain in the modelled future SMB changes as they are highly impacted by the meltwater runoff biases over the current climate.
Baptiste Vandecrux, Ruth Mottram, Peter L. Langen, Robert S. Fausto, Martin Olesen, C. Max Stevens, Vincent Verjans, Amber Leeson, Stefan Ligtenberg, Peter Kuipers Munneke, Sergey Marchenko, Ward van Pelt, Colin R. Meyer, Sebastian B. Simonsen, Achim Heilig, Samira Samimi, Shawn Marshall, Horst Machguth, Michael MacFerrin, Masashi Niwano, Olivia Miller, Clifford I. Voss, and Jason E. Box
The Cryosphere, 14, 3785–3810, https://doi.org/10.5194/tc-14-3785-2020, https://doi.org/10.5194/tc-14-3785-2020, 2020
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In the vast interior of the Greenland ice sheet, snow accumulates into a thick and porous layer called firn. Each summer, the firn retains part of the meltwater generated at the surface and buffers sea-level rise. In this study, we compare nine firn models traditionally used to quantify this retention at four sites and evaluate their performance against a set of in situ observations. We highlight limitations of certain model designs and give perspectives for future model development.
Christiaan T. van Dalum, Willem Jan van de Berg, Stef Lhermitte, and Michiel R. van den Broeke
The Cryosphere, 14, 3645–3662, https://doi.org/10.5194/tc-14-3645-2020, https://doi.org/10.5194/tc-14-3645-2020, 2020
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The reflectivity of sunlight, which is also known as albedo, is often inadequately modeled in regional climate models. Therefore, we have implemented a new snow and ice albedo scheme in the regional climate model RACMO2. In this study, we evaluate a new RACMO2 version for the Greenland ice sheet by using observations and the previous model version. RACMO2 output compares well with observations, and by including new processes we improve the ability of RACMO2 to make future climate projections.
Christine S. Hvidberg, Aslak Grinsted, Dorthe Dahl-Jensen, Shfaqat Abbas Khan, Anders Kusk, Jonas Kvist Andersen, Niklas Neckel, Anne Solgaard, Nanna B. Karlsson, Helle Astrid Kjær, and Paul Vallelonga
The Cryosphere, 14, 3487–3502, https://doi.org/10.5194/tc-14-3487-2020, https://doi.org/10.5194/tc-14-3487-2020, 2020
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The Northeast Greenland Ice Stream (NEGIS) extends around 600 km from its onset in the interior of Greenland to the coast. Several maps of surface velocity and topography in Greenland exist, but accuracy is limited due to the lack of validation data. Here we present results from a 5-year GPS survey in an interior section of NEGIS. We use the data to assess a list of satellite-derived ice velocity and surface elevation products and discuss the implications for the ice stream flow in the area.
Kang Yang, Aleah Sommers, Lauren C. Andrews, Laurence C. Smith, Xin Lu, Xavier Fettweis, and Manchun Li
The Cryosphere, 14, 3349–3365, https://doi.org/10.5194/tc-14-3349-2020, https://doi.org/10.5194/tc-14-3349-2020, 2020
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This study compares hourly supraglacial moulin discharge simulations from three surface meltwater routing models. Results show that these models are superior to simply using regional climate model runoff without routing, but different routing models, different-spatial-resolution DEMs, and parameterized seasonal evolution of supraglacial stream and river networks induce significant variability in diurnal moulin discharges and corresponding subglacial effective pressures.
Martin Rückamp, Heiko Goelzer, and Angelika Humbert
The Cryosphere, 14, 3309–3327, https://doi.org/10.5194/tc-14-3309-2020, https://doi.org/10.5194/tc-14-3309-2020, 2020
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Estimates of future sea-level contribution from the Greenland ice sheet have a large uncertainty based on different origins. We conduct numerical experiments to test the sensitivity of Greenland ice sheet projections to spatial resolution. Simulations with a higher resolution unveil up to 5 % more sea-level rise compared to coarser resolutions. The sensitivity depends on the magnitude of outlet glacier retreat. When no retreat is enforced, the sensitivity exhibits an inverse behaviour.
Heiko Goelzer, Sophie Nowicki, Anthony Payne, Eric Larour, Helene Seroussi, William H. Lipscomb, Jonathan Gregory, Ayako Abe-Ouchi, Andrew Shepherd, Erika Simon, Cécile Agosta, Patrick Alexander, Andy Aschwanden, Alice Barthel, Reinhard Calov, Christopher Chambers, Youngmin Choi, Joshua Cuzzone, Christophe Dumas, Tamsin Edwards, Denis Felikson, Xavier Fettweis, Nicholas R. Golledge, Ralf Greve, Angelika Humbert, Philippe Huybrechts, Sebastien Le clec'h, Victoria Lee, Gunter Leguy, Chris Little, Daniel P. Lowry, Mathieu Morlighem, Isabel Nias, Aurelien Quiquet, Martin Rückamp, Nicole-Jeanne Schlegel, Donald A. Slater, Robin S. Smith, Fiamma Straneo, Lev Tarasov, Roderik van de Wal, and Michiel van den Broeke
The Cryosphere, 14, 3071–3096, https://doi.org/10.5194/tc-14-3071-2020, https://doi.org/10.5194/tc-14-3071-2020, 2020
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In this paper we use a large ensemble of Greenland ice sheet models forced by six different global climate models to project ice sheet changes and sea-level rise contributions over the 21st century.
The results for two different greenhouse gas concentration scenarios indicate that the Greenland ice sheet will continue to lose mass until 2100, with contributions to sea-level rise of 90 ± 50 mm and 32 ± 17 mm for the high (RCP8.5) and low (RCP2.6) scenario, respectively.
Jan T. M. Lenaerts, M. Drew Camron, Christopher R. Wyburn-Powell, and Jennifer E. Kay
The Cryosphere, 14, 2253–2265, https://doi.org/10.5194/tc-14-2253-2020, https://doi.org/10.5194/tc-14-2253-2020, 2020
Willem Jan van de Berg, Erik van Meijgaard, and Lambertus H. van Ulft
The Cryosphere, 14, 1809–1827, https://doi.org/10.5194/tc-14-1809-2020, https://doi.org/10.5194/tc-14-1809-2020, 2020
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In times of increasing computer power, atmospheric models that estimate the surface mass balance of the Greenland can be run with increasing resolution. However, at which resolution is the error no longer determined by the lacking resolution but by model shortcomings? In this manuscript we show that for the majority of the southern part of the Greenland Ice Sheet, our study area, a model resolution of 20 km is sufficient although finer model resolutions are still beneficial.
Rosemary Leone, Joel Harper, Toby Meierbachtol, and Neil Humphrey
The Cryosphere, 14, 1703–1712, https://doi.org/10.5194/tc-14-1703-2020, https://doi.org/10.5194/tc-14-1703-2020, 2020
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Horizontal ice flow transports the firn layer of Greenland’s Percolation Zone as it undergoes burial by accumulation. Here we show that the firn density and temperature fields can reflect horizontal advection of the firn column across climate gradients, the magnitude of which varies around the ice sheet. Further, time series of melt features in ice cores from the percolation zone can contain a signature from ice motion that should not be conflated with that from climate change.
Brice Noël, Leonardus van Kampenhout, Willem Jan van de Berg, Jan T. M. Lenaerts, Bert Wouters, and Michiel R. van den Broeke
The Cryosphere, 14, 1425–1435, https://doi.org/10.5194/tc-14-1425-2020, https://doi.org/10.5194/tc-14-1425-2020, 2020
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We present a reconstruction of historical (1950–2014) surface mass balance of the Greenland ice sheet using the Community Earth System Model (CESM2; ~111 km) to force a high-resolution regional climate model (RACMO2; ~11 km), which is further refined to 1 km spatial resolution. For the first time, an Earth-system-model-based product, assimilating no observations, can reconstruct realistic historical ice sheet surface mass balance as well as the mass loss acceleration that started in the 1990s.
Marco Tedesco and Xavier Fettweis
The Cryosphere, 14, 1209–1223, https://doi.org/10.5194/tc-14-1209-2020, https://doi.org/10.5194/tc-14-1209-2020, 2020
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Unprecedented atmospheric conditions occurring in the summer of 2019 over Greenland promoted new record or close-to-record values of mass loss. Summer of 2019 was characterized by an exceptional persistence of anticyclonic conditions that enhanced melting.
Andrea Walter, Martin P. Lüthi, and Andreas Vieli
The Cryosphere, 14, 1051–1066, https://doi.org/10.5194/tc-14-1051-2020, https://doi.org/10.5194/tc-14-1051-2020, 2020
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Glacier calving plays a key role in the dynamic mass loss of ocean-terminating glaciers in Greenland. Source areas and volumes of 900 individual calving events were analysed for size and timing related to environmental forcings. We found that calving volume distribution and style vary along the calving front and are controlled by the water depth and front geometry. We suggest that in deep water both oceanic melt and subaquatic calving contribute substantially to the frontal mass loss.
Alison Delhasse, Christoph Kittel, Charles Amory, Stefan Hofer, Dirk van As, Robert S. Fausto, and Xavier Fettweis
The Cryosphere, 14, 957–965, https://doi.org/10.5194/tc-14-957-2020, https://doi.org/10.5194/tc-14-957-2020, 2020
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The ERA5 reanalysis of the ECMWF replaced the ERA-Interim in August 2019 and has never been evaluated over Greenland. The aim was to evaluate the performance of ERA5 to simulate the near-surface climate of the Greenland Ice sheet (GrIS) against ERA-Interim and regional climate models with the help of in situ observations from the PROMICE dataset. We also highlighted that polar regional climate models are still a useful tool to study the GrIS climate compared to ERA5.
Andrew J. Tedstone, Joseph M. Cook, Christopher J. Williamson, Stefan Hofer, Jenine McCutcheon, Tristram Irvine-Fynn, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 521–538, https://doi.org/10.5194/tc-14-521-2020, https://doi.org/10.5194/tc-14-521-2020, 2020
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Albedo describes how much light that hits a surface is reflected without being absorbed. Low-albedo ice surfaces melt more quickly. There are large differences in the albedo of bare-ice areas of the Greenland Ice Sheet. They are caused both by dark glacier algae and by the condition of the underlying ice. Changes occur over centimetres to metres, so satellites do not always detect real albedo changes. Estimates of melt made using satellite measurements therefore tend to be underestimates.
Achim Heilig, Olaf Eisen, Martin Schneebeli, Michael MacFerrin, C. Max Stevens, Baptiste Vandecrux, and Konrad Steffen
The Cryosphere, 14, 385–402, https://doi.org/10.5194/tc-14-385-2020, https://doi.org/10.5194/tc-14-385-2020, 2020
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We investigate the spatial representativeness of point observations of snow accumulation in SW Greenland. Such analyses have rarely been conducted but are necessary to link regional-scale observations from, e.g., remote-sensing data to firn cores and snow pits. The presented data reveal a low regional variability in density but snow depth can vary significantly. It is necessary to combine pits with spatial snow depth data to increase the regional representativeness of accumulation observations.
Raymond Sellevold, Leonardus van Kampenhout, Jan T. M. Lenaerts, Brice Noël, William H. Lipscomb, and Miren Vizcaino
The Cryosphere, 13, 3193–3208, https://doi.org/10.5194/tc-13-3193-2019, https://doi.org/10.5194/tc-13-3193-2019, 2019
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We evaluate a downscaling method to calculate ice sheet surface mass balance with global climate models, despite their coarse resolution. We compare it with high-resolution climate modeling. Despite absence of fine-scale simulation of individual energy and mass contributors, the method provides realistic vertical SMB gradients that can be used in forcing of ice sheet models, e.g., for sea level projections. Also, the climate model simulation is improved with the method implemented interactively.
Stephen J. Livingstone, Andrew J. Sole, Robert D. Storrar, Devin Harrison, Neil Ross, and Jade Bowling
The Cryosphere, 13, 2789–2796, https://doi.org/10.5194/tc-13-2789-2019, https://doi.org/10.5194/tc-13-2789-2019, 2019
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We report three new subglacial lakes close to the ice sheet margin of West Greenland. The lakes drained and refilled once each between 2009 and 2017, with two lakes draining in < 1 month during August 2014 and August 2015. The 2015 drainage caused a ~ 1-month down-glacier slowdown in ice flow and flooded the foreland, significantly modifying the braided river and depositing up to 8 m of sediment. These subglacial lakes offer accessible targets for future investigations and exploration.
Aku Riihelä, Michalea D. King, and Kati Anttila
The Cryosphere, 13, 2597–2614, https://doi.org/10.5194/tc-13-2597-2019, https://doi.org/10.5194/tc-13-2597-2019, 2019
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We used a 1982–2015 time series of satellite observations to examine changes in surface reflectivity (albedo) of the Greenland Ice Sheet. We found notable decreases in albedo over most of the ice sheet margins in July and August, particularly over the west coast and between 2000 and 2015. The results indicate that significant melt now occurs in areas 50 to 100 m higher up the ice sheet relative to the early 1980s. The albedo decrease is consistent and covarying with modelled ice sheet mass loss.
Ilaria Tabone, Alexander Robinson, Jorge Alvarez-Solas, and Marisa Montoya
The Cryosphere, 13, 1911–1923, https://doi.org/10.5194/tc-13-1911-2019, https://doi.org/10.5194/tc-13-1911-2019, 2019
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Recent reconstructions show that the North East Greenland Ice Stream (NEGIS) retreated away from its present-day position by 20–40 km during MIS-3. Atmospheric and external forcings were proposed as potential causes of this retreat, but the role of the ocean was not considered. Here, using a 3-D ice-sheet model, we suggest that oceanic warming is sufficient to induce a retreat of the NEGIS margin of many tens of kilometres during MIS-3, helping to explain this conundrum.
Baptiste Vandecrux, Michael MacFerrin, Horst Machguth, William T. Colgan, Dirk van As, Achim Heilig, C. Max Stevens, Charalampos Charalampidis, Robert S. Fausto, Elizabeth M. Morris, Ellen Mosley-Thompson, Lora Koenig, Lynn N. Montgomery, Clément Miège, Sebastian B. Simonsen, Thomas Ingeman-Nielsen, and Jason E. Box
The Cryosphere, 13, 845–859, https://doi.org/10.5194/tc-13-845-2019, https://doi.org/10.5194/tc-13-845-2019, 2019
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The perennial snow, or firn, on the Greenland ice sheet each summer stores part of the meltwater formed at the surface, buffering the ice sheet’s contribution to sea level. We gathered observations of firn air content, indicative of the space available in the firn to retain meltwater, and find that this air content remained stable in cold regions of the firn over the last 65 years but recently decreased significantly in western Greenland.
Marilena Oltmanns, Fiammetta Straneo, and Marco Tedesco
The Cryosphere, 13, 815–825, https://doi.org/10.5194/tc-13-815-2019, https://doi.org/10.5194/tc-13-815-2019, 2019
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By combining reanalysis, weather station and satellite data, we show that increases in surface melt over Greenland are initiated by large-scale precipitation events year-round. Estimates from a regional climate model suggest that the initiated melting more than doubled between 1988 and 2012, amounting to ~28 % of the overall melt and revealing that, despite the involved mass gain, precipitation events are contributing to the ice sheet's decline.
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.
Michalea D. King, Ian M. Howat, Seongsu Jeong, Myoung J. Noh, Bert Wouters, Brice Noël, and Michiel R. van den Broeke
The Cryosphere, 12, 3813–3825, https://doi.org/10.5194/tc-12-3813-2018, https://doi.org/10.5194/tc-12-3813-2018, 2018
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We derive the first continuous record of total ice discharged from all large Greenland outlet glaciers over the 2000–2016 period, resolving a distinct pattern of seasonal variability. We compare these results to glacier retreat and meltwater runoff and find that while runoff has a limited impact on ice discharge in summer, long-term changes in discharge are highly correlated to retreat. These results help to better understand Greenland outlet glacier sensitivity over a range of timescales.
Kang Yang, Laurence C. Smith, Leif Karlstrom, Matthew G. Cooper, Marco Tedesco, Dirk van As, Xiao Cheng, Zhuoqi Chen, and Manchun Li
The Cryosphere, 12, 3791–3811, https://doi.org/10.5194/tc-12-3791-2018, https://doi.org/10.5194/tc-12-3791-2018, 2018
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A high-resolution spatially lumped hydrologic surface routing model is proposed to simulate meltwater transport over bare ice surfaces. In an ice-covered catchment, meltwater is routed by slow interfluve flow (~10−3–10−4 m s−1) followed by fast open-channel flow (~10−1 m s−1). Seasonal evolution of supraglacial stream-river networks substantially alters the magnitude and timing of moulin discharge with implications for subglacial hydrology and ice dynamics.
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Short summary
Here, via analysis of radio-echo sounding data, we place a new observational constraint upon the basal water distribution beneath the Greenland Ice Sheet. In addition to the outlet glaciers, we demonstrate widespread water storage in the northern and eastern ice-sheet interior, a notable feature being a "corridor" of basal water extending from NorthGRIP to Petermann Glacier. The basal water distribution and its relationship with basal temperature provides a new constraint for numerical models.
Here, via analysis of radio-echo sounding data, we place a new observational constraint upon the...
