Articles | Volume 18, issue 3
https://doi.org/10.5194/tc-18-1105-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-18-1105-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Mar 2024
Research article |
| 05 Mar 2024
| 05 Mar 2024
The complex basal morphology and ice dynamics of the Nansen Ice Shelf, East Antarctica
Christine F. Dow
CORRESPONDING AUTHOR
Department of Geography and Environmental Management, University of Waterloo, Waterloo, N2L 3G1, Canada
Derek Mueller
Department of Geography and Environmental Studies, Carleton University, Ottawa, K1S 5B6, Canada
Peter Wray
Department of Geography and Environmental Management, University of Waterloo, Waterloo, N2L 3G1, Canada
Drew Friedrichs
Department of Civil and Environmental Engineering, University of California, Davis, Davis, CA 95616, USA
Tahoe Environmental Research Center, University of California, Davis, Incline Village, NV 89451, USA
Alexander L. Forrest
Department of Civil and Environmental Engineering, University of California, Davis, Davis, CA 95616, USA
Tahoe Environmental Research Center, University of California, Davis, Incline Village, NV 89451, USA
Jasmin B. McInerney
Department of Civil and Environmental Engineering, University of California, Davis, Davis, CA 95616, USA
Tahoe Environmental Research Center, University of California, Davis, Incline Village, NV 89451, USA
Jamin Greenbaum
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
Donald D. Blankenship
Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, USA
Choon Ki Lee
Division of Glacial Environment Research, Korea Polar Research Institute, Incheon 21990, Republic of Korea
Won Sang Lee
Division of Glacial Environment Research, Korea Polar Research Institute, Incheon 21990, Republic of Korea
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A subglacial lake was proposed to exist beneath Devon Ice Cap in the Canadian Arctic based on the analysis of airborne data. Our study presents a new interpretation of the subglacial material beneath the Devon Ice Cap from surface-based geophysical data. We show that there is no evidence of subglacial water, and the subglacial lake has likely been misidentified. Re-evaluation of the airborne data shows that overestimation of a critical processing parameter has likely occurred in prior studies.
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Using subglacial hydrology model outputs for Denman Glacier, East Antarctica, we investigated the effects of various friction laws and effective pressure inputs on ice dynamics modeling over the same glacier. The Schoof friction law outperformed the Budd friction law, and effective pressure outputs from the hydrology model outperformed a typically prescribed effective pressure. We propose an empirical prescription of effective pressure to be used in the absence of hydrology model outputs.
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The Cryosphere, 17, 4063–4078, https://doi.org/10.5194/tc-17-4063-2023, https://doi.org/10.5194/tc-17-4063-2023, 2023
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We design and propose a method that can evaluate the quality of glacier velocity maps. The method includes two numbers that we can calculate for each velocity map. Based on statistics and ice flow physics, velocity maps with numbers close to the recommended values are considered to have good quality. We test the method using the data from Kaskawulsh Glacier, Canada, and release an open-sourced software tool called GLAcier Feature Tracking testkit (GLAFT) to help users assess their velocity maps.
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The Cryosphere, 17, 2607–2624, https://doi.org/10.5194/tc-17-2607-2023, https://doi.org/10.5194/tc-17-2607-2023, 2023
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Water flow across the surface of the Greenland Ice Sheet controls the rate of water flow to the glacier bed. Here, we simulate surface water flow for a small catchment on the southwestern Greenland Ice Sheet. Our simulations predict significant differences in the form of surface water flow in high and low melt years depending on the rate and intensity of surface melt. These model outputs will be important in future work assessing the impact of surface water flow on subglacial water pressure.
Wei Wei, Donald D. Blankenship, Jamin S. Greenbaum, Noel Gourmelen, Christine F. Dow, Thomas G. Richter, Chad A. Greene, Duncan A. Young, SangHoon Lee, Tae-Wan Kim, Won Sang Lee, and Karen M. Assmann
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Getz Ice Shelf is the largest meltwater source from Antarctica of the Southern Ocean. This study compares the relative importance of the meltwater production of Getz from both ocean and subglacial sources. We show that basal melt rates are elevated where bathymetric troughs provide pathways for warm Circumpolar Deep Water to enter the Getz Ice Shelf cavity. In particular, we find that subshelf melting is enhanced where subglacially discharged fresh water flows across the grounding line.
William Kochtitzky, Dominic Winski, Erin McConnel, Karl Kreutz, Seth Campbell, Ellyn M. Enderlin, Luke Copland, Scott Williamson, Brittany Main, Christine Dow, and Hester Jiskoot
The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-72, https://doi.org/10.5194/tc-2019-72, 2019
Manuscript not accepted for further review
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Terrain formerly occupied by ice sheets in the last ice age allows us to parameterize models of basal water flow using terrain and data unavailable beneath current ice sheets. Using GlaDS, a 2D basal hydrology model, we explore the origin of murtoos, a specific landform found throughout Finland that is thought to mark the upper limit of channels beneath the ice. Our results validate many of the predictions of murtoo origins and demonstrate that such models can be used to explore past ice sheets.
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The ice sheets covering Antarctica have built up over millenia through successive snowfall events which become buried and preserved as internal surfaces of equal age detectable with ice-penetrating radar. This paper describes an international initiative to work together on this archival data to build a comprehensive 3-D picture of how old the ice is everywhere across Antarctica, and how this will be used to reconstruct past and predict future ice and climate behaviour.
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A subglacial lake was proposed to exist beneath Devon Ice Cap in the Canadian Arctic based on the analysis of airborne data. Our study presents a new interpretation of the subglacial material beneath the Devon Ice Cap from surface-based geophysical data. We show that there is no evidence of subglacial water, and the subglacial lake has likely been misidentified. Re-evaluation of the airborne data shows that overestimation of a critical processing parameter has likely occurred in prior studies.
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Koi McArthur, Felicity S. McCormack, and Christine F. Dow
The Cryosphere, 17, 4705–4727, https://doi.org/10.5194/tc-17-4705-2023, https://doi.org/10.5194/tc-17-4705-2023, 2023
Short summary
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Using subglacial hydrology model outputs for Denman Glacier, East Antarctica, we investigated the effects of various friction laws and effective pressure inputs on ice dynamics modeling over the same glacier. The Schoof friction law outperformed the Budd friction law, and effective pressure outputs from the hydrology model outperformed a typically prescribed effective pressure. We propose an empirical prescription of effective pressure to be used in the absence of hydrology model outputs.
Felicity S. McCormack, Jason L. Roberts, Bernd Kulessa, Alan Aitken, Christine F. Dow, Lawrence Bird, Benjamin K. Galton-Fenzi, Katharina Hochmuth, Richard S. Jones, Andrew N. Mackintosh, and Koi McArthur
The Cryosphere, 17, 4549–4569, https://doi.org/10.5194/tc-17-4549-2023, https://doi.org/10.5194/tc-17-4549-2023, 2023
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Changes in Antarctic surface elevation can cause changes in ice and basal water flow, impacting how much ice enters the ocean. We find that ice and basal water flow could divert from the Totten to the Vanderford Glacier, East Antarctica, under only small changes in the surface elevation, with implications for estimates of ice loss from this region. Further studies are needed to determine when this could occur and if similar diversions could occur elsewhere in Antarctica due to climate change.
Whyjay Zheng, Shashank Bhushan, Maximillian Van Wyk De Vries, William Kochtitzky, David Shean, Luke Copland, Christine Dow, Renette Jones-Ivey, and Fernando Pérez
The Cryosphere, 17, 4063–4078, https://doi.org/10.5194/tc-17-4063-2023, https://doi.org/10.5194/tc-17-4063-2023, 2023
Short summary
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We design and propose a method that can evaluate the quality of glacier velocity maps. The method includes two numbers that we can calculate for each velocity map. Based on statistics and ice flow physics, velocity maps with numbers close to the recommended values are considered to have good quality. We test the method using the data from Kaskawulsh Glacier, Canada, and release an open-sourced software tool called GLAcier Feature Tracking testkit (GLAFT) to help users assess their velocity maps.
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Earth Syst. Sci. Data, 15, 2695–2710, https://doi.org/10.5194/essd-15-2695-2023, https://doi.org/10.5194/essd-15-2695-2023, 2023
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This paper presents the release of over 60 years of ice thickness, bed elevation, and surface elevation data acquired over Antarctica by the international community. These data are a crucial component of the Antarctic Bedmap initiative which aims to produce a new map and datasets of Antarctic ice thickness and bed topography for the international glaciology and geophysical community.
Tim Hill and Christine F. Dow
The Cryosphere, 17, 2607–2624, https://doi.org/10.5194/tc-17-2607-2023, https://doi.org/10.5194/tc-17-2607-2023, 2023
Short summary
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Water flow across the surface of the Greenland Ice Sheet controls the rate of water flow to the glacier bed. Here, we simulate surface water flow for a small catchment on the southwestern Greenland Ice Sheet. Our simulations predict significant differences in the form of surface water flow in high and low melt years depending on the rate and intensity of surface melt. These model outputs will be important in future work assessing the impact of surface water flow on subglacial water pressure.
Kristian Chan, Cyril Grima, Anja Rutishauser, Duncan A. Young, Riley Culberg, and Donald D. Blankenship
The Cryosphere, 17, 1839–1852, https://doi.org/10.5194/tc-17-1839-2023, https://doi.org/10.5194/tc-17-1839-2023, 2023
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Julien A. Bodart, Robert G. Bingham, Duncan A. Young, Joseph A. MacGregor, David W. Ashmore, Enrica Quartini, Andrew S. Hein, David G. Vaughan, and Donald D. Blankenship
The Cryosphere, 17, 1497–1512, https://doi.org/10.5194/tc-17-1497-2023, https://doi.org/10.5194/tc-17-1497-2023, 2023
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Sarah S. Thompson, Bernd Kulessa, Adrian Luckman, Jacqueline A. Halpin, Jamin S. Greenbaum, Tyler Pelle, Feras Habbal, Jingxue Guo, Lenneke M. Jong, Jason L. Roberts, Bo Sun, and Donald D. Blankenship
The Cryosphere, 17, 157–174, https://doi.org/10.5194/tc-17-157-2023, https://doi.org/10.5194/tc-17-157-2023, 2023
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We use satellite imagery and ice penetrating radar to investigate the stability of the Shackleton system in East Antarctica. We find significant changes in surface structures across the system and observe a significant increase in ice flow speed (up to 50 %) on the floating part of Scott Glacier. We conclude that knowledge remains woefully insufficient to explain recent observed changes in the grounded and floating regions of the system.
Ji Sung Na, Taekyun Kim, Emilia Kyung Jin, Seung-Tae Yoon, Won Sang Lee, Sukyoung Yun, and Jiyeon Lee
The Cryosphere, 16, 3451–3468, https://doi.org/10.5194/tc-16-3451-2022, https://doi.org/10.5194/tc-16-3451-2022, 2022
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Beneath the Antarctic ice shelf, sub-ice-shelf plume flow that can cause turbulent mixing exists. In this study, we investigate how this flow affects ocean dynamics and ice melting near the ice front. Our results obtained by validated simulation show that higher turbulence intensity results in vigorous ice melting due to the high heat entrainment. Moreover, this flow with meltwater created by this flow highly affects the ocean overturning circulations near the ice front.
Anja Rutishauser, Donald D. Blankenship, Duncan A. Young, Natalie S. Wolfenbarger, Lucas H. Beem, Mark L. Skidmore, Ashley Dubnick, and Alison S. Criscitiello
The Cryosphere, 16, 379–395, https://doi.org/10.5194/tc-16-379-2022, https://doi.org/10.5194/tc-16-379-2022, 2022
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Recently, a hypersaline subglacial lake complex was hypothesized to lie beneath Devon Ice Cap, Canadian Arctic. Here, we present results from a follow-on targeted aerogeophysical survey. Our results support the evidence for a hypersaline subglacial lake and reveal an extensive brine network, suggesting more complex subglacial hydrological conditions than previously inferred. This hypersaline system may host microbial habitats, making it a compelling analog for bines on other icy worlds.
Reza Zeinali-Torbati, Ian D. Turnbull, Rocky S. Taylor, and Derek Mueller
The Cryosphere, 15, 5601–5621, https://doi.org/10.5194/tc-15-5601-2021, https://doi.org/10.5194/tc-15-5601-2021, 2021
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Using the reanalysis datasets and the Canadian Ice Island Drift, Deterioration and Detection database, a probabilistic model was developed to quantify ice island fracture probability under various atmospheric and oceanic conditions. The model identified water temperature as the most dominant variable behind ice island fracture events, while ocean currents played a minor role. The developed model offers a predictive capability and could be of particular interest to offshore and marine activities.
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.
Lucas H. Beem, Duncan A. Young, Jamin S. Greenbaum, Donald D. Blankenship, Marie G. P. Cavitte, Jingxue Guo, and Sun Bo
The Cryosphere, 15, 1719–1730, https://doi.org/10.5194/tc-15-1719-2021, https://doi.org/10.5194/tc-15-1719-2021, 2021
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Radar observation collected above Titan Dome of the East Antarctic Ice Sheet is used to describe ice geometry and test a hypothesis that ice beneath the dome is older than 1 million years. An important climate transition occurred between 1.25 million and 700 thousand years ago, and if ice old enough to study this period can be removed as an ice core, new insights into climate dynamics are expected. The new observations suggest the ice is too young – more likely 300 to 800 thousand years old.
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.
Laura E. Lindzey, Lucas H. Beem, Duncan A. Young, Enrica Quartini, Donald D. Blankenship, Choon-Ki Lee, Won Sang Lee, Jong Ik Lee, and Joohan Lee
The Cryosphere, 14, 2217–2233, https://doi.org/10.5194/tc-14-2217-2020, https://doi.org/10.5194/tc-14-2217-2020, 2020
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An extensive aerogeophysical survey including two active subglacial lakes was conducted over David Glacier, Antarctica. Laser altimetry shows that the lakes were at a highstand, while ice-penetrating radar has no unique signature for the lakes when compared to the broader basal environment. This suggests that active subglacial lakes are more likely to be part of a distributed subglacial hydrological system than to be discrete reservoirs, which has implications for future surveys and drilling.
Wei Wei, Donald D. Blankenship, Jamin S. Greenbaum, Noel Gourmelen, Christine F. Dow, Thomas G. Richter, Chad A. Greene, Duncan A. Young, SangHoon Lee, Tae-Wan Kim, Won Sang Lee, and Karen M. Assmann
The Cryosphere, 14, 1399–1408, https://doi.org/10.5194/tc-14-1399-2020, https://doi.org/10.5194/tc-14-1399-2020, 2020
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Getz Ice Shelf is the largest meltwater source from Antarctica of the Southern Ocean. This study compares the relative importance of the meltwater production of Getz from both ocean and subglacial sources. We show that basal melt rates are elevated where bathymetric troughs provide pathways for warm Circumpolar Deep Water to enter the Getz Ice Shelf cavity. In particular, we find that subshelf melting is enhanced where subglacially discharged fresh water flows across the grounding line.
Anna J. Crawford, Derek Mueller, Gregory Crocker, Laurent Mingo, Luc Desjardins, Dany Dumont, and Marcel Babin
The Cryosphere, 14, 1067–1081, https://doi.org/10.5194/tc-14-1067-2020, https://doi.org/10.5194/tc-14-1067-2020, 2020
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Large tabular icebergs (
ice islands) are symbols of climate change as well as marine hazards. We measured thickness along radar transects over two visits to a 14 km2 Arctic ice island and left automated equipment to monitor surface ablation and thickness over 1 year. We assess variation in thinning rates and calibrate an ice–ocean melt model with field data. Our work contributes to understanding ice island deterioration via logistically complex fieldwork in a remote environment.
Seung-Tae Yoon, Won Sang Lee, Craig Stevens, Stefan Jendersie, SungHyun Nam, Sukyoung Yun, Chung Yeon Hwang, Gwang Il Jang, and Jiyeon Lee
Ocean Sci., 16, 373–388, https://doi.org/10.5194/os-16-373-2020, https://doi.org/10.5194/os-16-373-2020, 2020
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We investigated the variability in high-salinity shelf water (HSSW) formation in the Terra Nova Bay polynya using hydrographic data from instrumented moorings and vessel-based profiles. We show that HSSW can be formed in the upper water column of the eastern Terra Nova Bay via polynya activity and convective processes, as well as how the nature of circulation in Terra Nova Bay influences HSSW production. This article also discusses the present results in the context of previous analyses.
William Kochtitzky, Dominic Winski, Erin McConnel, Karl Kreutz, Seth Campbell, Ellyn M. Enderlin, Luke Copland, Scott Williamson, Brittany Main, Christine Dow, and Hester Jiskoot
The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-72, https://doi.org/10.5194/tc-2019-72, 2019
Manuscript not accepted for further review
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Donjek Glacier has experienced eight instability events since 1935. Here we use a suite of weather and satellite data to understand the impacts of climate on instability events. We find that while there has been a consistent amount of snow fall between instability events, the relationship between the two is unclear as they are both very consistent on decade timescales. We show that we need further glacier observations to understand why these glaciers become unstable.
Richard H. Levy, Gavin B. Dunbar, Marcus J. Vandergoes, Jamie D. Howarth, Tony Kingan, Alex R. Pyne, Grant Brotherston, Michael Clarke, Bob Dagg, Matthew Hill, Evan Kenton, Steve Little, Darcy Mandeno, Chris Moy, Philip Muldoon, Patrick Doyle, Conrad Raines, Peter Rutland, Delia Strong, Marianna Terezow, Leise Cochrane, Remo Cossu, Sean Fitzsimons, Fabio Florindo, Alexander L. Forrest, Andrew R. Gorman, Darrell S. Kaufman, Min Kyung Lee, Xun Li, Pontus Lurcock, Nicholas McKay, Faye Nelson, Jennifer Purdie, Heidi A. Roop, S. Geoffrey Schladow, Abha Sood, Phaedra Upton, Sharon L. Walker, and Gary S. Wilson
Sci. Dril., 24, 41–50, https://doi.org/10.5194/sd-24-41-2018, https://doi.org/10.5194/sd-24-41-2018, 2018
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A new annually resolvable sedimentary record of southern hemisphere climate has been recovered from Lake Ohau, South Island, New Zealand. The Lake Ohau Climate History (LOCH) Project acquired cores from two sites that preserve an 80 m thick sequence of laminated mud that accumulated since the lake formed ~ 17 000 years ago. Cores were recovered using a purpose-built barge and drilling system designed to recover soft sediment from relatively thick sedimentary sequences at water depths up to 100 m.
Chad A. Greene, Duncan A. Young, David E. Gwyther, Benjamin K. Galton-Fenzi, and Donald D. Blankenship
The Cryosphere, 12, 2869–2882, https://doi.org/10.5194/tc-12-2869-2018, https://doi.org/10.5194/tc-12-2869-2018, 2018
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We show that Totten Ice Shelf accelerates each spring in response to the breakup of seasonal landfast sea ice at the ice shelf calving front. The previously unreported seasonal flow variability may have aliased measurements in at least one previous study of Totten's response to ocean forcing on interannual timescales. The role of sea ice in buttressing the flow of the ice shelf implies that long-term changes in sea ice cover could have impacts on the mass balance of the East Antarctic Ice Sheet.
Marie G. P. Cavitte, Frédéric Parrenin, Catherine Ritz, Duncan A. Young, Brice Van Liefferinge, Donald D. Blankenship, Massimo Frezzotti, and Jason L. Roberts
The Cryosphere, 12, 1401–1414, https://doi.org/10.5194/tc-12-1401-2018, https://doi.org/10.5194/tc-12-1401-2018, 2018
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We reconstruct the pattern of surface accumulation in the region around Dome C, East Antarctica, over the last 73 kyr. We use internal isochrones interpreted from ice-penetrating radar surveys and a 1-D ice flow model to invert for time-averaged and paleo-accumulation rates. We observe that surface accumulation patterns are stable through the last 73 kyr, consistent with current observed regional precipitation gradients and consistent interactions between prevailing winds and surface slope.
Andrew K. Hamilton, Bernard E. Laval, Derek R. Mueller, Warwick F. Vincent, and Luke Copland
The Cryosphere, 11, 2189–2211, https://doi.org/10.5194/tc-11-2189-2017, https://doi.org/10.5194/tc-11-2189-2017, 2017
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Meltwater runoff trapped by an ice shelf can create a freshwater lake floating directly on seawater. We show that the depth of the freshwater–seawater interface varies substantially due to changes in meltwater inflow and drainage under the ice shelf. By accounting for seasonality, the interface depth can be used to monitor long-term changes in the thickness of ice shelves. We show that the Milne Ice Shelf, Ellesmere Island, was stable before 2004, after which time the ice shelf thinned rapidly.
Duncan A. Young, Jason L. Roberts, Catherine Ritz, Massimo Frezzotti, Enrica Quartini, Marie G. P. Cavitte, Carly R. Tozer, Daniel Steinhage, Stefano Urbini, Hugh F. J. Corr, Tas van Ommen, and Donald D. Blankenship
The Cryosphere, 11, 1897–1911, https://doi.org/10.5194/tc-11-1897-2017, https://doi.org/10.5194/tc-11-1897-2017, 2017
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To find records of the greenhouse gases found in key periods of climate transition, we need to find sites of unmelted old ice at the base of the Antarctic ice sheet for ice core retrieval. A joint US–Australian–EU team performed a high-resolution survey of such a site (1 km line spacing) near Concordia Station in East Antarctica, using airborne ice-penetrating radar. We found promising targets in rough subglacial terrain, surrounded by subglacial lakes restricted below a minimum hydraulic head.
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.
Byeong-Hoon Kim, Choon-Ki Lee, Ki-Weon Seo, Won Sang Lee, and Ted Scambos
The Cryosphere, 10, 2971–2980, https://doi.org/10.5194/tc-10-2971-2016, https://doi.org/10.5194/tc-10-2971-2016, 2016
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Kamb Ice Stream (KIS) in Antarctica ceased rapid ice flow approximately 160 years ago, still influencing on the current mass balance of the West Antarctic Ice Sheet. We identify two previously unknown subglacial lakes beneath the stagnated trunk of the KIS. Rapid fill-drain hydrologic events over several months indicate that the lakes are probably connected by a subglacial drainage network. Our findings support previously published conceptual models of the KIS shutdown.
Alexander L. Forrest, Lars C. Lund-Hansen, Brian K. Sorrell, Isak Bowden-Floyd, Vanessa Lucieer, Remo Cossu, and Ian Hawes
The Cryosphere Discuss., https://doi.org/10.5194/tc-2016-186, https://doi.org/10.5194/tc-2016-186, 2016
Revised manuscript not accepted
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Measuring light conditions across sub-kilometer underwater transects of sea-ice in McMurdo Sound, Antarctica with an Autonomous Underwater Vehicle (AUV), we were able to derive estimates of ice algae biomass living at the ice/ocean interface at an unprecedented resolution. Characterizing ice algae communities at the appropriate scales of ecosystem variability is critical to understanding present day conditions and to predict how ecosystem response under future climate change scenarios.
Brad T. Gooch, Sasha P. Carter, Omar Ghattas, Duncan A. Young, and Donald D. Blankenship
The Cryosphere Discuss., https://doi.org/10.5194/tc-2016-141, https://doi.org/10.5194/tc-2016-141, 2016
Revised manuscript has not been submitted
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Our work investigates the potential significance of groundwater flow underneath the interior of East Antarctica where the ice doesn't rapidly melt. We attempt to describe the relationship between two hydrologic systems (water under the ice and in the ground) and how they might interact along a flow path between lakes under the ice. We find that groundwater is significant in regional water transport for melt water under the ice in areas of low melting in East Antarctica.
Christine F. Dow, Mauro A. Werder, Sophie Nowicki, and Ryan T. Walker
The Cryosphere, 10, 1381–1393, https://doi.org/10.5194/tc-10-1381-2016, https://doi.org/10.5194/tc-10-1381-2016, 2016
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We examine the development and drainage of subglacial lakes in the Antarctic using a finite element hydrology model. Model outputs show development of slow-moving pressure waves initiated from water funneled from a large catchment into the ice stream. Lake drainage occurs due to downstream channel formation and changing system hydraulic gradients. These model outputs have implications for understanding controls on ice stream dynamics.
H. Fischer, J. Severinghaus, E. Brook, E. Wolff, M. Albert, O. Alemany, R. Arthern, C. Bentley, D. Blankenship, J. Chappellaz, T. Creyts, D. Dahl-Jensen, M. Dinn, M. Frezzotti, S. Fujita, H. Gallee, R. Hindmarsh, D. Hudspeth, G. Jugie, K. Kawamura, V. Lipenkov, H. Miller, R. Mulvaney, F. Parrenin, F. Pattyn, C. Ritz, J. Schwander, D. Steinhage, T. van Ommen, and F. Wilhelms
Clim. Past, 9, 2489–2505, https://doi.org/10.5194/cp-9-2489-2013, https://doi.org/10.5194/cp-9-2489-2013, 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
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: Ice Shelf
An analysis of the interaction between surface and basal crevasses in ice shelves
The importance of cloud properties when assessing surface melting in an offline-coupled firn model over Ross Ice shelf, West Antarctica
Coupled ice–ocean interactions during future retreat of West Antarctic ice streams in the Amundsen Sea sector
Responses of the Pine Island and Thwaites glaciers to melt and sliding parameterizations
Calving of Ross Ice Shelf from wave erosion and hydrostatic stresses
Extreme melting at Greenland's largest floating ice tongue
Unveiling spatial variability within the Dotson Melt Channel through high-resolution basal melt rates from the Reference Elevation Model of Antarctica
Brief communication: Is vertical shear in an ice shelf (still) negligible?
Change in Antarctic ice shelf area from 2009 to 2019
Predicting ocean-induced ice-shelf melt rates using deep learning
Glaciological history and structural evolution of the Shackleton Ice Shelf system, East Antarctica, over the past 60 years
An assessment of basal melt parameterisations for Antarctic ice shelves
Surface melt on the Shackleton Ice Shelf, East Antarctica (2003–2021)
The effect of hydrology and crevasse wall contact on calving
On the evolution of an ice shelf melt channel at the base of Filchner Ice Shelf, from observations and viscoelastic modeling
Ongoing grounding line retreat and fracturing initiated at the Petermann Glacier ice shelf, Greenland, after 2016
Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations
Basal melt of the southern Filchner Ice Shelf, Antarctica
Automatic delineation of cracks with Sentinel-1 interferometry for monitoring ice shelf damage and calving
Weakening of the pinning point buttressing Thwaites Glacier, West Antarctica
Ice-shelf ocean boundary layer dynamics from large-eddy simulations
The potential of synthetic aperture radar interferometry for assessing meltwater lake dynamics on Antarctic ice shelves
Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf
Mechanics and dynamics of pinning points on the Shirase Coast, West Antarctica
Evidence for a grounding line fan at the onset of a basal channel under the ice shelf of Support Force Glacier, Antarctica, revealed by reflection seismics
The 32-year record-high surface melt in 2019/2020 on the northern George VI Ice Shelf, Antarctic Peninsula
The 2020 Larsen C Ice Shelf surface melt is a 40-year record high
Diagnosing the sensitivity of grounding-line flux to changes in sub-ice-shelf melting
A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections
Lateral meltwater transfer across an Antarctic ice shelf
Ice shelf rift propagation: stability, three-dimensional effects, and the role of marginal weakening
Getz Ice Shelf melt enhanced by freshwater discharge from beneath the West Antarctic Ice Sheet
Differential interferometric synthetic aperture radar for tide modelling in Antarctic ice-shelf grounding zones
Ice shelf basal melt rates from a high-resolution digital elevation model (DEM) record for Pine Island Glacier, Antarctica
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars
Past and future dynamics of the Brunt Ice Shelf from seabed bathymetry and ice shelf geometry
Maryam Zarrinderakht, Christian Schoof, and Anthony Peirce
The Cryosphere, 18, 3841–3856, https://doi.org/10.5194/tc-18-3841-2024, https://doi.org/10.5194/tc-18-3841-2024, 2024
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The objective of the study is to understand the interactions between surface and basal crevasses by conducting a stability analysis and addressing the implications of the findings for potential calving laws. The study's findings indicate that, while the propagation of one crack in the case of two aligned surface and basal crevasses does not significantly reinforce the propagation of the other, the presence of multiple crevasses on one side enhances stability and decreases crack propagation.
Nicolaj Hansen, Andrew Orr, Xun Zou, Fredrik Boberg, Thomas J. Bracegirdle, Ella Gilbert, Peter L. Langen, Matthew A. Lazzara, Ruth Mottram, Tony Phillips, Ruth Price, Sebastian B. Simonsen, and Stuart Webster
The Cryosphere, 18, 2897–2916, https://doi.org/10.5194/tc-18-2897-2024, https://doi.org/10.5194/tc-18-2897-2024, 2024
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We investigated a melt event over the Ross Ice Shelf. We use regional climate models and a firn model to simulate the melt and compare the results with satellite data. We find that the firn model aligned well with observed melt days in certain parts of the ice shelf. The firn model had challenges accurately simulating the melt extent in the western sector. We identified potential reasons for these discrepancies, pointing to limitations in the models related to representing the cloud properties.
David T. Bett, Alexander T. Bradley, C. Rosie Williams, Paul R. Holland, Robert J. Arthern, and Daniel N. Goldberg
The Cryosphere, 18, 2653–2675, https://doi.org/10.5194/tc-18-2653-2024, https://doi.org/10.5194/tc-18-2653-2024, 2024
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A new ice–ocean model simulates future ice sheet evolution in the Amundsen Sea sector of Antarctica. Substantial ice retreat is simulated in all scenarios, with some retreat still occurring even with no future ocean melting. The future of small "pinning points" (islands of ice that contact the seabed) is an important control on this retreat. Ocean melting is crucial in causing these features to go afloat, providing the link by which climate change may affect this sector's sea level contribution.
Ian Joughin, Daniel Shapero, and Pierre Dutrieux
The Cryosphere, 18, 2583–2601, https://doi.org/10.5194/tc-18-2583-2024, https://doi.org/10.5194/tc-18-2583-2024, 2024
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The Pine Island and Thwaites glaciers are losing ice to the ocean rapidly as warmer water melts their floating ice shelves. Models help determine how much such glaciers will contribute to sea level. We find that ice loss varies in response to how much melting the ice shelves are subjected to. Our estimated losses are also sensitive to how much the friction beneath the glaciers is reduced as it goes afloat. Melt-forced sea level rise from these glaciers is likely to be less than 10 cm by 2300.
Nicolas B. Sartore, Till J. W. Wagner, Matthew R. Siegfried, Nimish Pujara, and Lucas K. Zoet
EGUsphere, https://doi.org/10.5194/egusphere-2024-571, https://doi.org/10.5194/egusphere-2024-571, 2024
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We investigate how waves erode the front of Antarctica’s largest ice shelf, the Ross Ice Shelf, and how this erosion results in bending forces that can cause intermediate-scale calving (with icebergs of lengths ~100 m). We compare satellite observations to theoretical estimates of wave erosion and ice shelf bending to better understand the processes underlying this type of calving. We assess that these events may be responsible for roughly 25 % of the ice lost at the front of the Ross Ice Shelf.
Ole Zeising, Niklas Neckel, Nils Dörr, Veit Helm, Daniel Steinhage, Ralph Timmermann, and Angelika Humbert
The Cryosphere, 18, 1333–1357, https://doi.org/10.5194/tc-18-1333-2024, https://doi.org/10.5194/tc-18-1333-2024, 2024
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The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier.
Ann-Sofie Priergaard Zinck, Bert Wouters, Erwin Lambert, and Stef Lhermitte
The Cryosphere, 17, 3785–3801, https://doi.org/10.5194/tc-17-3785-2023, https://doi.org/10.5194/tc-17-3785-2023, 2023
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The ice shelves in Antarctica are melting from below, which puts their stability at risk. Therefore, it is important to observe how much and where they are melting. In this study we use high-resolution satellite imagery to derive 50 m resolution basal melt rates of the Dotson Ice Shelf. With the high resolution of our product we are able to uncover small-scale features which may in the future help us to understand the state and fate of the Antarctic ice shelves and their (in)stability.
Chris Miele, Timothy C. Bartholomaus, and Ellyn M. Enderlin
The Cryosphere, 17, 2701–2704, https://doi.org/10.5194/tc-17-2701-2023, https://doi.org/10.5194/tc-17-2701-2023, 2023
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Vertical shear stress (the stress orientation usually associated with vertical gradients in horizontal velocities) is a key component of the stress balance of ice shelves. However, partly due to historical assumptions, vertical shear is often misspoken of today as
negligiblein ice shelf models. We address this miscommunication, providing conceptual guidance regarding this often misrepresented stress. Fundamentally, vertical shear is required to balance thickness gradients in ice shelves.
Julia R. Andreasen, Anna E. Hogg, and Heather L. Selley
The Cryosphere, 17, 2059–2072, https://doi.org/10.5194/tc-17-2059-2023, https://doi.org/10.5194/tc-17-2059-2023, 2023
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There are few long-term, high spatial resolution observations of ice shelf change in Antarctica over the past 3 decades. In this study, we use high spatial resolution observations to map the annual calving front location on 34 ice shelves around Antarctica from 2009 to 2019 using satellite data. The results provide a comprehensive assessment of ice front migration across Antarctica over the last decade.
Sebastian H. R. Rosier, Christopher Y. S. Bull, Wai L. Woo, and G. Hilmar Gudmundsson
The Cryosphere, 17, 499–518, https://doi.org/10.5194/tc-17-499-2023, https://doi.org/10.5194/tc-17-499-2023, 2023
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Future ice loss from Antarctica could raise sea levels by several metres, and key to this is the rate at which the ocean melts the ice sheet from below. Existing methods for modelling this process are either computationally expensive or very simplified. We present a new approach using machine learning to mimic the melt rates calculated by an ocean model but in a fraction of the time. This approach may provide a powerful alternative to existing methods, without compromising on accuracy or speed.
Sarah S. Thompson, Bernd Kulessa, Adrian Luckman, Jacqueline A. Halpin, Jamin S. Greenbaum, Tyler Pelle, Feras Habbal, Jingxue Guo, Lenneke M. Jong, Jason L. Roberts, Bo Sun, and Donald D. Blankenship
The Cryosphere, 17, 157–174, https://doi.org/10.5194/tc-17-157-2023, https://doi.org/10.5194/tc-17-157-2023, 2023
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We use satellite imagery and ice penetrating radar to investigate the stability of the Shackleton system in East Antarctica. We find significant changes in surface structures across the system and observe a significant increase in ice flow speed (up to 50 %) on the floating part of Scott Glacier. We conclude that knowledge remains woefully insufficient to explain recent observed changes in the grounded and floating regions of the system.
Clara Burgard, Nicolas C. Jourdain, Ronja Reese, Adrian Jenkins, and Pierre Mathiot
The Cryosphere, 16, 4931–4975, https://doi.org/10.5194/tc-16-4931-2022, https://doi.org/10.5194/tc-16-4931-2022, 2022
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The ocean-induced melt at the base of the floating ice shelves around Antarctica is one of the largest uncertainty factors in the Antarctic contribution to future sea-level rise. We assess the performance of several existing parameterisations in simulating basal melt rates on a circum-Antarctic scale, using an ocean simulation resolving the cavities below the shelves as our reference. We find that the simple quadratic slope-independent and plume parameterisations yield the best compromise.
Dominic Saunderson, Andrew Mackintosh, Felicity McCormack, Richard Selwyn Jones, and Ghislain Picard
The Cryosphere, 16, 4553–4569, https://doi.org/10.5194/tc-16-4553-2022, https://doi.org/10.5194/tc-16-4553-2022, 2022
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We investigate the variability in surface melt on the Shackleton Ice Shelf in East Antarctica over the last 2 decades (2003–2021). Using daily satellite observations and the machine learning approach of a self-organising map, we identify nine distinct spatial patterns of melt. These patterns allow comparisons of melt within and across melt seasons and highlight the importance of both air temperatures and local controls such as topography, katabatic winds, and albedo in driving surface melt.
Maryam Zarrinderakht, Christian Schoof, and Anthony Peirce
The Cryosphere, 16, 4491–4512, https://doi.org/10.5194/tc-16-4491-2022, https://doi.org/10.5194/tc-16-4491-2022, 2022
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Iceberg calving is the reason for more than half of mass loss in both Greenland and Antarctica and indirectly contributes to sea-level rise. Our study models iceberg calving by linear elastic fracture mechanics and uses a boundary element method to compute crack tip propagation. This model handles the contact condition: preventing crack faces from penetrating into each other and enabling the derivation of calving laws for different forms of hydrological forcing.
Angelika Humbert, Julia Christmann, Hugh F. J. Corr, Veit Helm, Lea-Sophie Höyns, Coen Hofstede, Ralf Müller, Niklas Neckel, Keith W. Nicholls, Timm Schultz, Daniel Steinhage, Michael Wolovick, and Ole Zeising
The Cryosphere, 16, 4107–4139, https://doi.org/10.5194/tc-16-4107-2022, https://doi.org/10.5194/tc-16-4107-2022, 2022
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Ice shelves are normally flat structures that fringe the Antarctic continent. At some locations they have channels incised into their underside. On Filchner Ice Shelf, such a channel is more than 50 km long and up to 330 m high. We conducted field measurements of basal melt rates and found a maximum of 2 m yr−1. Simulations represent the geometry evolution of the channel reasonably well. There is no reason to assume that this type of melt channel is destabilizing ice shelves.
Romain Millan, Jeremie Mouginot, Anna Derkacheva, Eric Rignot, Pietro Milillo, Enrico Ciraci, Luigi Dini, and Anders Bjørk
The Cryosphere, 16, 3021–3031, https://doi.org/10.5194/tc-16-3021-2022, https://doi.org/10.5194/tc-16-3021-2022, 2022
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We detect for the first time a dramatic retreat of the grounding line of Petermann Glacier, a major glacier of the Greenland Ice Sheet. Using satellite data, we also observe a speedup of the glacier and a fracturing of the ice shelf. This sequence of events is coherent with ocean warming in this region and suggests that Petermann Glacier has initiated a phase of destabilization, which is of prime importance for the stability and future contribution of the Greenland Ice Sheet to sea level rise.
Johannes Feldmann, Ronja Reese, Ricarda Winkelmann, and Anders Levermann
The Cryosphere, 16, 1927–1940, https://doi.org/10.5194/tc-16-1927-2022, https://doi.org/10.5194/tc-16-1927-2022, 2022
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We use a numerical model to simulate the flow of a simplified, buttressed Antarctic-type outlet glacier with an attached ice shelf. We find that after a few years of perturbation such a glacier responds much stronger to melting under the ice-shelf shear margins than to melting in the central fast streaming part of the ice shelf. This study explains the underlying physical mechanism which might gain importance in the future if melt rates under the Antarctic ice shelves continue to increase.
Ole Zeising, Daniel Steinhage, Keith W. Nicholls, Hugh F. J. Corr, Craig L. Stewart, and Angelika Humbert
The Cryosphere, 16, 1469–1482, https://doi.org/10.5194/tc-16-1469-2022, https://doi.org/10.5194/tc-16-1469-2022, 2022
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Remote-sensing-derived basal melt rates of ice shelves are of great importance due to their capability to cover larger areas. We performed in situ measurements with a phase-sensitive radar on the southern Filchner Ice Shelf, showing moderate melt rates and low small-scale spatial variability. The comparison with remote-sensing-based melt rates revealed large differences caused by the estimation of vertical strain rates from remote sensing velocity fields that modern fields can overcome.
Ludivine Libert, Jan Wuite, and Thomas Nagler
The Cryosphere, 16, 1523–1542, https://doi.org/10.5194/tc-16-1523-2022, https://doi.org/10.5194/tc-16-1523-2022, 2022
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Open fractures are important to monitor because they weaken the ice shelf structure. We propose a novel approach using synthetic aperture radar (SAR) interferometry for automatic delineation of ice shelf cracks. The method is applied to Sentinel-1 images of Brunt Ice Shelf, Antarctica, and the propagation of the North Rift, which led to iceberg calving in February 2021, is traced. It is also shown that SAR interferometry is more sensitive to rifting than SAR backscatter and optical imagery.
Christian T. Wild, Karen E. Alley, Atsuhiro Muto, Martin Truffer, Ted A. Scambos, and Erin C. Pettit
The Cryosphere, 16, 397–417, https://doi.org/10.5194/tc-16-397-2022, https://doi.org/10.5194/tc-16-397-2022, 2022
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Thwaites Glacier has the potential to significantly raise Antarctica's contribution to global sea-level rise by the end of this century. Here, we use satellite measurements of surface elevation to show that its floating part is close to losing contact with an underwater ridge that currently acts to stabilize. We then use computer models of ice flow to simulate the predicted unpinning, which show that accelerated ice discharge into the ocean follows the breakup of the floating part.
Carolyn Branecky Begeman, Xylar Asay-Davis, and Luke Van Roekel
The Cryosphere, 16, 277–295, https://doi.org/10.5194/tc-16-277-2022, https://doi.org/10.5194/tc-16-277-2022, 2022
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This study uses ocean modeling at ultra-high resolution to study the small-scale ocean mixing that controls ice-shelf melting. It offers some insights into the relationship between ice-shelf melting and ocean temperature far from the ice base, which may help us project how fast ice will melt when ocean waters entering the cavity warm. This study adds to a growing body of research that indicates we need a more sophisticated treatment of ice-shelf melting in coarse-resolution ocean models.
Weiran Li, Stef Lhermitte, and Paco López-Dekker
The Cryosphere, 15, 5309–5322, https://doi.org/10.5194/tc-15-5309-2021, https://doi.org/10.5194/tc-15-5309-2021, 2021
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Surface meltwater lakes have been observed on several Antarctic ice shelves in field studies and optical images. Meltwater lakes can drain and refreeze, increasing the fragility of the ice shelves. The combination of synthetic aperture radar (SAR) backscatter and interferometric information (InSAR) can provide the cryosphere community with the possibility to continuously assess the dynamics of the meltwater lakes, potentially helping to facilitate the study of ice shelves in a changing climate.
Karen E. Alley, Christian T. Wild, Adrian Luckman, Ted A. Scambos, Martin Truffer, Erin C. Pettit, Atsuhiro Muto, Bruce Wallin, Marin Klinger, Tyler Sutterley, Sarah F. Child, Cyrus Hulen, Jan T. M. Lenaerts, Michelle Maclennan, Eric Keenan, and Devon Dunmire
The Cryosphere, 15, 5187–5203, https://doi.org/10.5194/tc-15-5187-2021, https://doi.org/10.5194/tc-15-5187-2021, 2021
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We present a 20-year, satellite-based record of velocity and thickness change on the Thwaites Eastern Ice Shelf (TEIS), the largest remaining floating extension of Thwaites Glacier (TG). TG holds the single greatest control on sea-level rise over the next few centuries, so it is important to understand changes on the TEIS, which controls much of TG's flow into the ocean. Our results suggest that the TEIS is progressively destabilizing and is likely to disintegrate over the next few decades.
Holly Still and Christina Hulbe
The Cryosphere, 15, 2647–2665, https://doi.org/10.5194/tc-15-2647-2021, https://doi.org/10.5194/tc-15-2647-2021, 2021
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Pinning points, locations where floating ice shelves run aground, modify ice flow and thickness. We use a model to quantify the Ross Ice Shelf and tributary ice stream response to a group of pinning points. Ice stream sensitivity to pinning points is conditioned by basal drag, and thus basal properties, upstream of the grounding line. Without the pinning points, a redistribution of resistive stresses supports faster flow and increased mass flux but with a negligible change in total ice volume.
Coen Hofstede, Sebastian Beyer, Hugh Corr, Olaf Eisen, Tore Hattermann, Veit Helm, Niklas Neckel, Emma C. Smith, Daniel Steinhage, Ole Zeising, and Angelika Humbert
The Cryosphere, 15, 1517–1535, https://doi.org/10.5194/tc-15-1517-2021, https://doi.org/10.5194/tc-15-1517-2021, 2021
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Support Force Glacier rapidly flows into Filcher Ice Shelf of Antarctica. As we know little about this glacier and its subglacial drainage, we used seismic energy to map the transition area from grounded to floating ice where a drainage channel enters the ocean cavity. Soft sediments close to the grounding line are probably transported by this drainage channel. The constant ice thickness over the steeply dipping seabed of the ocean cavity suggests a stable transition and little basal melting.
Alison F. Banwell, Rajashree Tri Datta, Rebecca L. Dell, Mahsa Moussavi, Ludovic Brucker, Ghislain Picard, Christopher A. Shuman, and Laura A. Stevens
The Cryosphere, 15, 909–925, https://doi.org/10.5194/tc-15-909-2021, https://doi.org/10.5194/tc-15-909-2021, 2021
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Ice shelves are thick floating layers of glacier ice extending from the glaciers on land that buttress much of the Antarctic Ice Sheet and help to protect it from losing ice to the ocean. However, the stability of ice shelves is vulnerable to meltwater lakes that form on their surfaces during the summer. This study focuses on the northern George VI Ice Shelf on the western side of the AP, which had an exceptionally long and extensive melt season in 2019/2020 compared to the previous 31 seasons.
Suzanne Bevan, Adrian Luckman, Harry Hendon, and Guomin Wang
The Cryosphere, 14, 3551–3564, https://doi.org/10.5194/tc-14-3551-2020, https://doi.org/10.5194/tc-14-3551-2020, 2020
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In February 2020, along with record-breaking high temperatures in the region, satellite images showed that the surface of the largest remaining ice shelf on the Antarctic Peninsula was experiencing a lot of melt. Using archived satellite data we show that this melt was greater than any in the past 40 years. The extreme melt followed unusual weather patterns further north, highlighting the importance of long-range links between the tropics and high latitudes and the impact on ice-shelf stability.
Tong Zhang, Stephen F. Price, Matthew J. Hoffman, Mauro Perego, and Xylar Asay-Davis
The Cryosphere, 14, 3407–3424, https://doi.org/10.5194/tc-14-3407-2020, https://doi.org/10.5194/tc-14-3407-2020, 2020
Nicolas C. Jourdain, Xylar Asay-Davis, Tore Hattermann, Fiammetta Straneo, Hélène Seroussi, Christopher M. Little, and Sophie Nowicki
The Cryosphere, 14, 3111–3134, https://doi.org/10.5194/tc-14-3111-2020, https://doi.org/10.5194/tc-14-3111-2020, 2020
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To predict the future Antarctic contribution to sea level rise, we need to use ice sheet models. The Ice Sheet Model Intercomparison Project for AR6 (ISMIP6) builds an ensemble of ice sheet projections constrained by atmosphere and ocean projections from the 6th Coupled Model Intercomparison Project (CMIP6). In this work, we present and assess a method to derive ice shelf basal melting in ISMIP6 from the CMIP6 ocean outputs, and we give examples of projected melt rates.
Rebecca Dell, Neil Arnold, Ian Willis, Alison Banwell, Andrew Williamson, Hamish Pritchard, and Andrew Orr
The Cryosphere, 14, 2313–2330, https://doi.org/10.5194/tc-14-2313-2020, https://doi.org/10.5194/tc-14-2313-2020, 2020
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A semi-automated method is developed from pre-existing work to track surface water bodies across Antarctic ice shelves over time, using data from Sentinel-2 and Landsat 8. This method is applied to the Nivlisen Ice Shelf for the 2016–2017 melt season. The results reveal two large linear meltwater systems, which hold 63 % of the peak total surface meltwater volume on 26 January 2017. These meltwater systems migrate towards the ice shelf front as the melt season progresses.
Bradley Paul Lipovsky
The Cryosphere, 14, 1673–1683, https://doi.org/10.5194/tc-14-1673-2020, https://doi.org/10.5194/tc-14-1673-2020, 2020
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Ice shelves promote the stability of marine ice sheets and therefore reduce the ice sheet contribution to sea level rise. Ice shelf rifts are through-cutting fractures that jeopardize this stabilizing tendency. Here, I carry out the first-ever 3D modeling of ice shelf rifts. I find that the overall ice shelf geometry – particularly the ice shelf margins – alters rift stability. This work paves the way to a more realistic depiction of rifting in ice sheet models.
Wei Wei, Donald D. Blankenship, Jamin S. Greenbaum, Noel Gourmelen, Christine F. Dow, Thomas G. Richter, Chad A. Greene, Duncan A. Young, SangHoon Lee, Tae-Wan Kim, Won Sang Lee, and Karen M. Assmann
The Cryosphere, 14, 1399–1408, https://doi.org/10.5194/tc-14-1399-2020, https://doi.org/10.5194/tc-14-1399-2020, 2020
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Getz Ice Shelf is the largest meltwater source from Antarctica of the Southern Ocean. This study compares the relative importance of the meltwater production of Getz from both ocean and subglacial sources. We show that basal melt rates are elevated where bathymetric troughs provide pathways for warm Circumpolar Deep Water to enter the Getz Ice Shelf cavity. In particular, we find that subshelf melting is enhanced where subglacially discharged fresh water flows across the grounding line.
Christian T. Wild, Oliver J. Marsh, and Wolfgang Rack
The Cryosphere, 13, 3171–3191, https://doi.org/10.5194/tc-13-3171-2019, https://doi.org/10.5194/tc-13-3171-2019, 2019
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In Antarctica, ocean tides control the motion of ice sheets near the coastline as well as melt rates underneath the floating ice. By combining the spatial advantage of rare but highly accurate satellite images with the temporal advantage of tide-prediction models, vertical displacement of floating ice due to ocean tides can now be predicted accurately. This allows the detailed study of ice-flow dynamics in areas that matter the most to the stability of Antarctica's ice sheets.
David E. Shean, Ian R. Joughin, Pierre Dutrieux, Benjamin E. Smith, and Etienne Berthier
The Cryosphere, 13, 2633–2656, https://doi.org/10.5194/tc-13-2633-2019, https://doi.org/10.5194/tc-13-2633-2019, 2019
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We produced an 8-year, high-resolution DEM record for Pine Island Glacier (PIG), a site of substantial Antarctic mass loss in recent decades. We developed methods to study the spatiotemporal evolution of ice shelf basal melting, which is responsible for ~ 60 % of PIG mass loss. We present shelf-wide basal melt rates and document relative melt rates for kilometer-scale basal channels and keels, offering new indirect observations of ice–ocean interaction beneath a vulnerable ice shelf.
Katrin Lindbäck, Geir Moholdt, Keith W. Nicholls, Tore Hattermann, Bhanu Pratap, Meloth Thamban, and Kenichi Matsuoka
The Cryosphere, 13, 2579–2595, https://doi.org/10.5194/tc-13-2579-2019, https://doi.org/10.5194/tc-13-2579-2019, 2019
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In this study, we used a ground-penetrating radar technique to measure melting at high precision under Nivlisen, an ice shelf in central Dronning Maud Land, East Antarctica. We found that summer-warmed ocean surface waters can increase melting close to the ice shelf front. Our study shows the use of and need for measurements in the field to monitor Antarctica's coastal margins; these detailed variations in basal melting are not captured in satellite data but are vital to predict future changes.
Dominic A. Hodgson, Tom A. Jordan, Jan De Rydt, Peter T. Fretwell, Samuel A. Seddon, David Becker, Kelly A. Hogan, Andrew M. Smith, and David G. Vaughan
The Cryosphere, 13, 545–556, https://doi.org/10.5194/tc-13-545-2019, https://doi.org/10.5194/tc-13-545-2019, 2019
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The Brunt Ice Shelf in Antarctica is home to Halley VIa, the latest in a series of six British research stations that have occupied the ice shelf since 1956. A recent rapid growth of rifts in the Brunt Ice Shelf signals the onset of its largest calving event since records began. Here we consider whether this calving event will lead to a new steady state for the ice shelf or an unpinning from the bed, which could predispose it to accelerated flow or collapse.
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Short summary
Ice shelves are a key control on Antarctic contribution to sea level rise. We examine the Nansen Ice Shelf in East Antarctica using a combination of field-based and satellite data. We find the basal topography of the ice shelf is highly variable, only partially visible in satellite datasets. We also find that the thinnest region of the ice shelf is altered over time by ice flow rates and ocean melting. These processes can cause fractures to form that eventually result in large calving events.
Ice shelves are a key control on Antarctic contribution to sea level rise. We examine the Nansen...
