Articles | Volume 13, issue 2
https://doi.org/10.5194/tc-13-665-2019
© Author(s) 2019. 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-13-665-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
26 Feb 2019
Research article | Highlight paper |
| 26 Feb 2019
| 26 Feb 2019
The Reference Elevation Model of Antarctica
Ian M. Howat
CORRESPONDING AUTHOR
Byrd Polar and Climate Research Center, Ohio State University, Columbus, OH, USA
School of Earth Sciences, Ohio State University, Columbus, OH, USA
Claire Porter
Polar Geospatial Center, University of Minnesota, St. Paul, MN, USA
Benjamin E. Smith
Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
Myoung-Jong Noh
Byrd Polar and Climate Research Center, Ohio State University, Columbus, OH, USA
Paul Morin
Polar Geospatial Center, University of Minnesota, St. Paul, MN, USA
Related authors
Allison M. Chartrand, Ian M. Howat, Ian R. Joughin, and Benjamin E. Smith
The Cryosphere, 18, 4971–4992, https://doi.org/10.5194/tc-18-4971-2024, https://doi.org/10.5194/tc-18-4971-2024, 2024
Short summary
Short summary
This study uses high-resolution remote-sensing data to show that shrinking of the West Antarctic Thwaites Glacier’s ice shelf (floating extension) is exacerbated by several sub-ice-shelf meltwater channels that form as the glacier transitions from full contact with the seafloor to fully floating. In mapping these channels, the position of the transition zone, and thinning rates of the Thwaites Glacier, this work elucidates important processes driving its rapid contribution to sea level rise.
Qi Liang, Wanxin Xiao, Ian Howat, Xiao Cheng, Fengming Hui, Zhuoqi Chen, Mi Jiang, and Lei Zheng
The Cryosphere, 16, 2671–2681, https://doi.org/10.5194/tc-16-2671-2022, https://doi.org/10.5194/tc-16-2671-2022, 2022
Short summary
Short summary
Using multi-temporal ArcticDEM and ICESat-2 altimetry data, we document changes in surface elevation of a subglacial lake basin from 2012 to 2021. The long-term measurements show that the subglacial lake was recharged by surface meltwater and that a rapid drainage event in late August 2019 induced an abrupt ice velocity change. Multiple factors regulate the episodic filling and drainage of the lake. Our study also reveals ~ 64 % of the surface meltwater successfully descended to the bed.
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
Short summary
Short summary
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.
Ian M. Howat, Santiago de la Peña, Darin Desilets, and Gary Womack
The Cryosphere, 12, 2099–2108, https://doi.org/10.5194/tc-12-2099-2018, https://doi.org/10.5194/tc-12-2099-2018, 2018
Short summary
Short summary
In this paper we present the first application of cosmic ray neutron sensing for continuously measuring in situ accumulation on an ice sheet. We validate these results with manual snow coring and snow stake measurements, showing that the cosmic ray observations are of similar if not better accuracy. We also present our observations of variability in accumulation over 24 months at Summit Camp, Greenland. We conclude that cosmic ray sensing has a high potential for measuring surface mass balance.
Joaquín M. C. Belart, Etienne Berthier, Eyjólfur Magnússon, Leif S. Anderson, Finnur Pálsson, Thorsteinn Thorsteinsson, Ian M. Howat, Guðfinna Aðalgeirsdóttir, Tómas Jóhannesson, and Alexander H. Jarosch
The Cryosphere, 11, 1501–1517, https://doi.org/10.5194/tc-11-1501-2017, https://doi.org/10.5194/tc-11-1501-2017, 2017
Short summary
Short summary
Sub-meter satellite stereo images (Pléiades and WorldView2) are used to accurately measure snow accumulation and winter mass balance of Drangajökull ice cap. This is done by creating and comparing accurate digital elevation models. A glacier-wide geodetic mass balance of 3.33 ± 0.23 m w.e. is derived between October 2014 and May 2015. This method could be easily transposable to remote glaciated areas where seasonal mass balance measurements (especially winter accumulation) are lacking.
Stephen F. Price, Matthew J. Hoffman, Jennifer A. Bonin, Ian M. Howat, Thomas Neumann, Jack Saba, Irina Tezaur, Jeffrey Guerber, Don P. Chambers, Katherine J. Evans, Joseph H. Kennedy, Jan Lenaerts, William H. Lipscomb, Mauro Perego, Andrew G. Salinger, Raymond S. Tuminaro, Michiel R. van den Broeke, and Sophie M. J. Nowicki
Geosci. Model Dev., 10, 255–270, https://doi.org/10.5194/gmd-10-255-2017, https://doi.org/10.5194/gmd-10-255-2017, 2017
Short summary
Short summary
We introduce the Cryospheric Model Comparison Tool (CmCt) and propose qualitative and quantitative metrics for evaluating ice sheet model simulations against observations. Greenland simulations using the Community Ice Sheet Model are compared to gravimetry and altimetry observations from 2003 to 2013. We show that the CmCt can be used to score simulations of increasing complexity relative to observations of dynamic change in Greenland over the past decade.
Brice Noël, Willem Jan van de Berg, Horst Machguth, Stef Lhermitte, Ian Howat, Xavier Fettweis, and Michiel R. van den Broeke
The Cryosphere, 10, 2361–2377, https://doi.org/10.5194/tc-10-2361-2016, https://doi.org/10.5194/tc-10-2361-2016, 2016
Short summary
Short summary
We present a 1 km resolution data set (1958–2015) of daily Greenland ice sheet surface mass balance (SMB), statistically downscaled from the data of RACMO2.3 at 11 km using elevation dependence, precipitation and bare ice albedo corrections. The data set resolves Greenland narrow ablation zones and local outlet glaciers, and shows more realistic SMB patterns, owing to enhanced runoff at the ice sheet margins. An evaluation of the product against SMB measurements shows improved agreement.
Michiel R. van den Broeke, Ellyn M. Enderlin, Ian M. Howat, Peter Kuipers Munneke, Brice P. Y. Noël, Willem Jan van de Berg, Erik van Meijgaard, and Bert Wouters
The Cryosphere, 10, 1933–1946, https://doi.org/10.5194/tc-10-1933-2016, https://doi.org/10.5194/tc-10-1933-2016, 2016
Short summary
Short summary
We present recent (1958–2015) mass balance time series for the Greenland ice sheet. We show that recent mass loss is caused by a combination of increased surface meltwater runoff and solid ice discharge. Most meltwater above 2000 m a.s.l. refreezes in the cold firn and does not leave the ice sheet, but this goes at the expense of firn heating and densifying. In spite of a temporary rebound in 2013, it appears that the ice sheet remains in a state of persistent mass loss.
P. Kuipers Munneke, S. R. M. Ligtenberg, B. P. Y. Noël, I. M. Howat, J. E. Box, E. Mosley-Thompson, J. R. McConnell, K. Steffen, J. T. Harper, S. B. Das, and M. R. van den Broeke
The Cryosphere, 9, 2009–2025, https://doi.org/10.5194/tc-9-2009-2015, https://doi.org/10.5194/tc-9-2009-2015, 2015
Short summary
Short summary
The snow layer on top of the Greenland Ice Sheet is changing: it is thickening in the high and cold interior due to increased snowfall, while it is thinning around the margins. The marginal thinning is caused by compaction, and by more melt.
This knowledge is important: there are satellites that measure volume change of the ice sheet. It can be caused by increased ice discharge, or by compaction of the snow layer. Here, we quantify the latter, so that we can translate volume to mass change.
S. de la Peña, I. M. Howat, P. W. Nienow, M. R. van den Broeke, E. Mosley-Thompson, S. F. Price, D. Mair, B. Noël, and A. J. Sole
The Cryosphere, 9, 1203–1211, https://doi.org/10.5194/tc-9-1203-2015, https://doi.org/10.5194/tc-9-1203-2015, 2015
Short summary
Short summary
This paper presents an assessment of changes in the near-surface structure of the accumulation zone of the Greenland Ice Sheet caused by an increase of melt at higher elevations in the last decade, especially during the unusually warm years of 2010 and 2012. The increase in melt and firn densification complicate the interpretation of changes in the ice volume, and the observed increase in firn ice content may reduce the important meltwater buffering capacity of the Greenland Ice Sheet.
I. M. Howat, C. Porter, M. J. Noh, B. E. Smith, and S. Jeong
The Cryosphere, 9, 103–108, https://doi.org/10.5194/tc-9-103-2015, https://doi.org/10.5194/tc-9-103-2015, 2015
Short summary
Short summary
In the summer of 2011, a large crater appeared in the surface of the Greenland Ice Sheet. It formed when a subglacial lake, equivalent to 10,000 swimming pools, catastrophically drained in less than 14 days. This is the first direct evidence that surface meltwater that drains through cracks to the bed of the ice sheet can build up in subglacial lakes over long periods of time. The sudden drainage may have been due to more surface melting and an increase in meltwater reaching the bed.
I. M. Howat, A. Negrete, and B. E. Smith
The Cryosphere, 8, 1509–1518, https://doi.org/10.5194/tc-8-1509-2014, https://doi.org/10.5194/tc-8-1509-2014, 2014
E. M. Enderlin, I. M. Howat, and A. Vieli
The Cryosphere, 7, 1579–1590, https://doi.org/10.5194/tc-7-1579-2013, https://doi.org/10.5194/tc-7-1579-2013, 2013
E. M. Enderlin, I. M. Howat, and A. Vieli
The Cryosphere, 7, 1007–1015, https://doi.org/10.5194/tc-7-1007-2013, https://doi.org/10.5194/tc-7-1007-2013, 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
I. M. Howat, S. de la Peña, J. H. van Angelen, J. T. M. Lenaerts, and M. R. van den Broeke
The Cryosphere, 7, 201–204, https://doi.org/10.5194/tc-7-201-2013, https://doi.org/10.5194/tc-7-201-2013, 2013
Allison M. Chartrand, Ian M. Howat, Ian R. Joughin, and Benjamin E. Smith
The Cryosphere, 18, 4971–4992, https://doi.org/10.5194/tc-18-4971-2024, https://doi.org/10.5194/tc-18-4971-2024, 2024
Short summary
Short summary
This study uses high-resolution remote-sensing data to show that shrinking of the West Antarctic Thwaites Glacier’s ice shelf (floating extension) is exacerbated by several sub-ice-shelf meltwater channels that form as the glacier transitions from full contact with the seafloor to fully floating. In mapping these channels, the position of the transition zone, and thinning rates of the Thwaites Glacier, this work elucidates important processes driving its rapid contribution to sea level rise.
Michael Studinger, Benjamin E. Smith, Nathan Kurtz, Alek Petty, Tyler Sutterley, and Rachel Tilling
The Cryosphere, 18, 2625–2652, https://doi.org/10.5194/tc-18-2625-2024, https://doi.org/10.5194/tc-18-2625-2024, 2024
Short summary
Short summary
We use green lidar data and natural-color imagery over sea ice to quantify elevation biases potentially impacting estimates of change in ice thickness of the polar regions. We complement our analysis using a model of scattering of light in snow and ice that predicts the shape of lidar waveforms reflecting from snow and ice surfaces based on the shape of the transmitted pulse. We find that biased elevations exist in airborne and spaceborne data products from green lidars.
Benjamin Smith, Michael Studinger, Tyler Sutterley, Zachary Fair, and Thomas Neumann
The Cryosphere Discuss., https://doi.org/10.5194/tc-2023-147, https://doi.org/10.5194/tc-2023-147, 2023
Revised manuscript under review for TC
Short summary
Short summary
This study investigates errors (biases) that may result when green lasers are used to measure the elevation of glaciers and ice sheets. These biases are important because if the snow or ice on top of the ice sheet changes, it can make the elevation of the ice appear to change by the wrong amount. We measure these biases over the Greenland Ice Sheet with a laser system on an airplane, and explore how the use of satellite data can let us correct for the biases.
Inès N. Otosaka, Andrew Shepherd, Erik R. Ivins, Nicole-Jeanne Schlegel, Charles Amory, Michiel R. van den Broeke, Martin Horwath, Ian Joughin, Michalea D. King, Gerhard Krinner, Sophie Nowicki, Anthony J. Payne, Eric Rignot, Ted Scambos, Karen M. Simon, Benjamin E. Smith, Louise S. Sørensen, Isabella Velicogna, Pippa L. Whitehouse, Geruo A, Cécile Agosta, Andreas P. Ahlstrøm, Alejandro Blazquez, William Colgan, Marcus E. Engdahl, Xavier Fettweis, Rene Forsberg, Hubert Gallée, Alex Gardner, Lin Gilbert, Noel Gourmelen, Andreas Groh, Brian C. Gunter, Christopher Harig, Veit Helm, Shfaqat Abbas Khan, Christoph Kittel, Hannes Konrad, Peter L. Langen, Benoit S. Lecavalier, Chia-Chun Liang, Bryant D. Loomis, Malcolm McMillan, Daniele Melini, Sebastian H. Mernild, Ruth Mottram, Jeremie Mouginot, Johan Nilsson, Brice Noël, Mark E. Pattle, William R. Peltier, Nadege Pie, Mònica Roca, Ingo Sasgen, Himanshu V. Save, Ki-Weon Seo, Bernd Scheuchl, Ernst J. O. Schrama, Ludwig Schröder, Sebastian B. Simonsen, Thomas Slater, Giorgio Spada, Tyler C. Sutterley, Bramha Dutt Vishwakarma, Jan Melchior van Wessem, David Wiese, Wouter van der Wal, and Bert Wouters
Earth Syst. Sci. Data, 15, 1597–1616, https://doi.org/10.5194/essd-15-1597-2023, https://doi.org/10.5194/essd-15-1597-2023, 2023
Short summary
Short summary
By measuring changes in the volume, gravitational attraction, and ice flow of Greenland and Antarctica from space, we can monitor their mass gain and loss over time. Here, we present a new record of the Earth’s polar ice sheet mass balance produced by aggregating 50 satellite-based estimates of ice sheet mass change. This new assessment shows that the ice sheets have lost (7.5 x 1012) t of ice between 1992 and 2020, contributing 21 mm to sea level rise.
Benjamin E. Smith, Brooke Medley, Xavier Fettweis, Tyler Sutterley, Patrick Alexander, David Porter, and Marco Tedesco
The Cryosphere, 17, 789–808, https://doi.org/10.5194/tc-17-789-2023, https://doi.org/10.5194/tc-17-789-2023, 2023
Short summary
Short summary
We use repeated satellite measurements of the height of the Greenland ice sheet to learn about how three computational models of snowfall, melt, and snow compaction represent actual changes in the ice sheet. We find that the models do a good job of estimating how the parts of the ice sheet near the coast have changed but that two of the models have trouble representing surface melt for the highest part of the ice sheet. This work provides suggestions for how to better model snowmelt.
Brooke Medley, Thomas A. Neumann, H. Jay Zwally, Benjamin E. Smith, and C. Max Stevens
The Cryosphere, 16, 3971–4011, https://doi.org/10.5194/tc-16-3971-2022, https://doi.org/10.5194/tc-16-3971-2022, 2022
Short summary
Short summary
Satellite altimeters measure the height or volume change over Earth's ice sheets, but in order to understand how that change translates into ice mass, we must account for various processes at the surface. Specifically, snowfall events generate large, transient increases in surface height, yet snow fall has a relatively low density, which means much of that height change is composed of air. This air signal must be removed from the observed height changes before we can assess ice mass change.
Qi Liang, Wanxin Xiao, Ian Howat, Xiao Cheng, Fengming Hui, Zhuoqi Chen, Mi Jiang, and Lei Zheng
The Cryosphere, 16, 2671–2681, https://doi.org/10.5194/tc-16-2671-2022, https://doi.org/10.5194/tc-16-2671-2022, 2022
Short summary
Short summary
Using multi-temporal ArcticDEM and ICESat-2 altimetry data, we document changes in surface elevation of a subglacial lake basin from 2012 to 2021. The long-term measurements show that the subglacial lake was recharged by surface meltwater and that a rapid drainage event in late August 2019 induced an abrupt ice velocity change. Multiple factors regulate the episodic filling and drainage of the lake. Our study also reveals ~ 64 % of the surface meltwater successfully descended to the bed.
Andrew O. Hoffman, Knut Christianson, Daniel Shapero, Benjamin E. Smith, and Ian Joughin
The Cryosphere, 14, 4603–4609, https://doi.org/10.5194/tc-14-4603-2020, https://doi.org/10.5194/tc-14-4603-2020, 2020
Short summary
Short summary
The West Antarctic Ice Sheet has long been considered geometrically prone to collapse, and Thwaites Glacier, the largest glacier in the Amundsen Sea, is likely in the early stages of disintegration. Using observations of Thwaites Glacier velocity and elevation change, we show that the transport of ~2 km3 of water beneath Thwaites Glacier has only a small and transient effect on glacier speed relative to ongoing thinning driven by ocean melt.
Ian Joughin, David E. Shean, Benjamin E. Smith, and Dana Floricioiu
The Cryosphere, 14, 211–227, https://doi.org/10.5194/tc-14-211-2020, https://doi.org/10.5194/tc-14-211-2020, 2020
Short summary
Short summary
Jakobshavn Isbræ, considered to be Greenland's fastest glacier, has varied its speed and thinned dramatically since the 1990s. Here we examine the glacier's behaviour over the last decade to better understand this behaviour. We find that when the floating ice (mélange) in front of the glacier freezes in place during the winter, it can control the glacier's speed and thinning rate. A recently colder ocean has strengthened this mélange, allowing the glacier to recoup some of its previous losses.
David A. Lilien, Ian Joughin, Benjamin Smith, and Noel Gourmelen
The Cryosphere, 13, 2817–2834, https://doi.org/10.5194/tc-13-2817-2019, https://doi.org/10.5194/tc-13-2817-2019, 2019
Short summary
Short summary
We used a number of computer simulations to understand the recent retreat of a rapidly changing group of glaciers in West Antarctica. We found that significant melt underneath the floating extensions of the glaciers, driven by relatively warm ocean water at depth, was likely needed to cause the large retreat that has been observed. If melt continues around current rates, retreat is likely to continue through the coming century and extend beyond the present-day drainage area of these glaciers.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Ian Joughin, Ben E. Smith, and Ian Howat
The Cryosphere, 12, 2211–2227, https://doi.org/10.5194/tc-12-2211-2018, https://doi.org/10.5194/tc-12-2211-2018, 2018
Short summary
Short summary
We describe several new ice velocity maps produced using Landsat 8 and Copernicus Sentinel 1A/B data. We focus on several sites where we analyse these data in conjunction with earlier data from this project, which extend back to the year 2000. In particular, we find that Jakobshavn Isbræ began slowing substantially in 2017. The growing duration of these records will allow more robust analyses of the processes controlling fast flow and how they are affected by climate and other forcings.
Ian M. Howat, Santiago de la Peña, Darin Desilets, and Gary Womack
The Cryosphere, 12, 2099–2108, https://doi.org/10.5194/tc-12-2099-2018, https://doi.org/10.5194/tc-12-2099-2018, 2018
Short summary
Short summary
In this paper we present the first application of cosmic ray neutron sensing for continuously measuring in situ accumulation on an ice sheet. We validate these results with manual snow coring and snow stake measurements, showing that the cosmic ray observations are of similar if not better accuracy. We also present our observations of variability in accumulation over 24 months at Summit Camp, Greenland. We conclude that cosmic ray sensing has a high potential for measuring surface mass balance.
David A. Lilien, Ian Joughin, Benjamin Smith, and David E. Shean
The Cryosphere, 12, 1415–1431, https://doi.org/10.5194/tc-12-1415-2018, https://doi.org/10.5194/tc-12-1415-2018, 2018
Short summary
Short summary
We used remotely sensed data and a numerical model to study the processes controlling the stability of two rapidly changing ice shelves in West Antarctica. Both these ice shelves have been losing mass since at least 1996, primarily as a result of ocean-forced melt. We find that this imbalance likely results from changes initiated around 1970 or earlier. Our results also show that the shelves’ differing speedup is controlled by the strength of their margins and their grounding-line positions.
David E. Shean, Knut Christianson, Kristine M. Larson, Stefan R. M. Ligtenberg, Ian R. Joughin, Ben E. Smith, C. Max Stevens, Mitchell Bushuk, and David M. Holland
The Cryosphere, 11, 2655–2674, https://doi.org/10.5194/tc-11-2655-2017, https://doi.org/10.5194/tc-11-2655-2017, 2017
Short summary
Short summary
We used long-term GPS data and interferometric reflectometry (GPS-IR) to measure velocity, strain rate and surface elevation for the PIG ice shelf – a site of significant mass loss in recent decades. We combined these observations with high-res DEMs and firn model output to constrain surface mass balance and basal melt rates. We document notable spatial variability in basal melt rates but limited temporal variability from 2012 to 2014 despite significant changes in sub-shelf ocean heat content.
Andrew G. Fountain, Juan C. Fernandez-Diaz, Maciej Obryk, Joseph Levy, Michael Gooseff, David J. Van Horn, Paul Morin, and Ramesh Shrestha
Earth Syst. Sci. Data, 9, 435–443, https://doi.org/10.5194/essd-9-435-2017, https://doi.org/10.5194/essd-9-435-2017, 2017
Short summary
Short summary
We present detailed surface elevation measurements for the McMurdo Dry Valleys, Antarctica, and surroundings, derived from aerial lidar surveys flown in the austral summer of 2014–2015 as part of an effort to understand landscape changes over the past decade. Lidar return density varied from 2 to > 10 returns per square meter with an average of about 5 returns per square meter. vertical and horizontal accuracies are estimated to be 7 cm and 3 cm, respectively.
Joaquín M. C. Belart, Etienne Berthier, Eyjólfur Magnússon, Leif S. Anderson, Finnur Pálsson, Thorsteinn Thorsteinsson, Ian M. Howat, Guðfinna Aðalgeirsdóttir, Tómas Jóhannesson, and Alexander H. Jarosch
The Cryosphere, 11, 1501–1517, https://doi.org/10.5194/tc-11-1501-2017, https://doi.org/10.5194/tc-11-1501-2017, 2017
Short summary
Short summary
Sub-meter satellite stereo images (Pléiades and WorldView2) are used to accurately measure snow accumulation and winter mass balance of Drangajökull ice cap. This is done by creating and comparing accurate digital elevation models. A glacier-wide geodetic mass balance of 3.33 ± 0.23 m w.e. is derived between October 2014 and May 2015. This method could be easily transposable to remote glaciated areas where seasonal mass balance measurements (especially winter accumulation) are lacking.
Benjamin E. Smith, Noel Gourmelen, Alexander Huth, and Ian Joughin
The Cryosphere, 11, 451–467, https://doi.org/10.5194/tc-11-451-2017, https://doi.org/10.5194/tc-11-451-2017, 2017
Short summary
Short summary
In this paper we investigate elevation changes of Thwaites Glacier, West Antarctica, one of the main sources of excess ice discharge into the ocean. We find that in early 2013, four subglacial lakes separated by 100 km drained suddenly, discharging more than 3 km3 of water under the fastest part of the glacier in less than 6 months. Concurrent ice-speed measurements show only minor changes, suggesting that ice dynamics are not strongly sensitive to changes in water flow.
Stephen F. Price, Matthew J. Hoffman, Jennifer A. Bonin, Ian M. Howat, Thomas Neumann, Jack Saba, Irina Tezaur, Jeffrey Guerber, Don P. Chambers, Katherine J. Evans, Joseph H. Kennedy, Jan Lenaerts, William H. Lipscomb, Mauro Perego, Andrew G. Salinger, Raymond S. Tuminaro, Michiel R. van den Broeke, and Sophie M. J. Nowicki
Geosci. Model Dev., 10, 255–270, https://doi.org/10.5194/gmd-10-255-2017, https://doi.org/10.5194/gmd-10-255-2017, 2017
Short summary
Short summary
We introduce the Cryospheric Model Comparison Tool (CmCt) and propose qualitative and quantitative metrics for evaluating ice sheet model simulations against observations. Greenland simulations using the Community Ice Sheet Model are compared to gravimetry and altimetry observations from 2003 to 2013. We show that the CmCt can be used to score simulations of increasing complexity relative to observations of dynamic change in Greenland over the past decade.
Brice Noël, Willem Jan van de Berg, Horst Machguth, Stef Lhermitte, Ian Howat, Xavier Fettweis, and Michiel R. van den Broeke
The Cryosphere, 10, 2361–2377, https://doi.org/10.5194/tc-10-2361-2016, https://doi.org/10.5194/tc-10-2361-2016, 2016
Short summary
Short summary
We present a 1 km resolution data set (1958–2015) of daily Greenland ice sheet surface mass balance (SMB), statistically downscaled from the data of RACMO2.3 at 11 km using elevation dependence, precipitation and bare ice albedo corrections. The data set resolves Greenland narrow ablation zones and local outlet glaciers, and shows more realistic SMB patterns, owing to enhanced runoff at the ice sheet margins. An evaluation of the product against SMB measurements shows improved agreement.
Michiel R. van den Broeke, Ellyn M. Enderlin, Ian M. Howat, Peter Kuipers Munneke, Brice P. Y. Noël, Willem Jan van de Berg, Erik van Meijgaard, and Bert Wouters
The Cryosphere, 10, 1933–1946, https://doi.org/10.5194/tc-10-1933-2016, https://doi.org/10.5194/tc-10-1933-2016, 2016
Short summary
Short summary
We present recent (1958–2015) mass balance time series for the Greenland ice sheet. We show that recent mass loss is caused by a combination of increased surface meltwater runoff and solid ice discharge. Most meltwater above 2000 m a.s.l. refreezes in the cold firn and does not leave the ice sheet, but this goes at the expense of firn heating and densifying. In spite of a temporary rebound in 2013, it appears that the ice sheet remains in a state of persistent mass loss.
D. N. Goldberg, P. Heimbach, I. Joughin, and B. Smith
The Cryosphere, 9, 2429–2446, https://doi.org/10.5194/tc-9-2429-2015, https://doi.org/10.5194/tc-9-2429-2015, 2015
Short summary
Short summary
We calibrate a time-dependent ice model through optimal fit to transient observations of surface elevation and velocity, a novel procedure in glaciology and in particular for an ice stream with a dynamic grounding line. We show this procedure gives a level of confidence in model projections that cannot be achieved through more commonly used glaciological data assimilation methods. We show that Smith Glacier is in a state of retreat regardless of climatic forcing for the next several decades.
P. Kuipers Munneke, S. R. M. Ligtenberg, B. P. Y. Noël, I. M. Howat, J. E. Box, E. Mosley-Thompson, J. R. McConnell, K. Steffen, J. T. Harper, S. B. Das, and M. R. van den Broeke
The Cryosphere, 9, 2009–2025, https://doi.org/10.5194/tc-9-2009-2015, https://doi.org/10.5194/tc-9-2009-2015, 2015
Short summary
Short summary
The snow layer on top of the Greenland Ice Sheet is changing: it is thickening in the high and cold interior due to increased snowfall, while it is thinning around the margins. The marginal thinning is caused by compaction, and by more melt.
This knowledge is important: there are satellites that measure volume change of the ice sheet. It can be caused by increased ice discharge, or by compaction of the snow layer. Here, we quantify the latter, so that we can translate volume to mass change.
S. de la Peña, I. M. Howat, P. W. Nienow, M. R. van den Broeke, E. Mosley-Thompson, S. F. Price, D. Mair, B. Noël, and A. J. Sole
The Cryosphere, 9, 1203–1211, https://doi.org/10.5194/tc-9-1203-2015, https://doi.org/10.5194/tc-9-1203-2015, 2015
Short summary
Short summary
This paper presents an assessment of changes in the near-surface structure of the accumulation zone of the Greenland Ice Sheet caused by an increase of melt at higher elevations in the last decade, especially during the unusually warm years of 2010 and 2012. The increase in melt and firn densification complicate the interpretation of changes in the ice volume, and the observed increase in firn ice content may reduce the important meltwater buffering capacity of the Greenland Ice Sheet.
I. M. Howat, C. Porter, M. J. Noh, B. E. Smith, and S. Jeong
The Cryosphere, 9, 103–108, https://doi.org/10.5194/tc-9-103-2015, https://doi.org/10.5194/tc-9-103-2015, 2015
Short summary
Short summary
In the summer of 2011, a large crater appeared in the surface of the Greenland Ice Sheet. It formed when a subglacial lake, equivalent to 10,000 swimming pools, catastrophically drained in less than 14 days. This is the first direct evidence that surface meltwater that drains through cracks to the bed of the ice sheet can build up in subglacial lakes over long periods of time. The sudden drainage may have been due to more surface melting and an increase in meltwater reaching the bed.
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
I. M. Howat, A. Negrete, and B. E. Smith
The Cryosphere, 8, 1509–1518, https://doi.org/10.5194/tc-8-1509-2014, https://doi.org/10.5194/tc-8-1509-2014, 2014
B. Medley, I. Joughin, B. E. Smith, S. B. Das, E. J. Steig, H. Conway, S. Gogineni, C. Lewis, A. S. Criscitiello, J. R. McConnell, M. R. van den Broeke, J. T. M. Lenaerts, D. H. Bromwich, J. P. Nicolas, and C. Leuschen
The Cryosphere, 8, 1375–1392, https://doi.org/10.5194/tc-8-1375-2014, https://doi.org/10.5194/tc-8-1375-2014, 2014
D. Callens, K. Matsuoka, D. Steinhage, B. Smith, E. Witrant, and F. Pattyn
The Cryosphere, 8, 867–875, https://doi.org/10.5194/tc-8-867-2014, https://doi.org/10.5194/tc-8-867-2014, 2014
M. J. Siegert, N. Ross, H. Corr, B. Smith, T. Jordan, R. G. Bingham, F. Ferraccioli, D. M. Rippin, and A. Le Brocq
The Cryosphere, 8, 15–24, https://doi.org/10.5194/tc-8-15-2014, https://doi.org/10.5194/tc-8-15-2014, 2014
E. M. Enderlin, I. M. Howat, and A. Vieli
The Cryosphere, 7, 1579–1590, https://doi.org/10.5194/tc-7-1579-2013, https://doi.org/10.5194/tc-7-1579-2013, 2013
E. M. Enderlin, I. M. Howat, and A. Vieli
The Cryosphere, 7, 1007–1015, https://doi.org/10.5194/tc-7-1007-2013, https://doi.org/10.5194/tc-7-1007-2013, 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
I. M. Howat, S. de la Peña, J. H. van Angelen, J. T. M. Lenaerts, and M. R. van den Broeke
The Cryosphere, 7, 201–204, https://doi.org/10.5194/tc-7-201-2013, https://doi.org/10.5194/tc-7-201-2013, 2013
Related subject area
Discipline: Ice sheets | Subject: Remote Sensing
Change in grounding line location on the Antarctic Peninsula measured using a tidal motion offset correlation method
AWI-ICENet1: a convolutional neural network retracker for ice altimetry
Sentinel-1 detection of ice slabs on the Greenland Ice Sheet
A Framework for Automated Supraglacial Lake Detection and Depth Retrieval in ICESat-2 Photon Data Across the Greenland and Antarctic Ice Sheets
Mapping the extent of giant Antarctic icebergs with deep learning
Mapping Antarctic crevasses and their evolution with deep learning applied to satellite radar imagery
AutoTerm: an automated pipeline for glacier terminus extraction using machine learning and a “big data” repository of Greenland glacier termini
Recent changes in drainage route and outburst magnitude of the Russell Glacier ice-dammed lake, West Greenland
Grounding line retreat and tide-modulated ocean channels at Moscow University and Totten Glacier ice shelves, East Antarctica
Seasonal land-ice-flow variability in the Antarctic Peninsula
Empirical correction of systematic orthorectification error in Sentinel-2 velocity fields for Greenlandic outlet glaciers
A leading-edge-based method for correction of slope-induced errors in ice-sheet heights derived from radar altimetry
An empirical algorithm to map perennial firn aquifers and ice slabs within the Greenland Ice Sheet using satellite L-band microwave radiometry
Supraglacial lake bathymetry automatically derived from ICESat-2 constraining lake depth estimates from multi-source satellite imagery
Penetration of interferometric radar signals in Antarctic snow
Brief communication: Ice sheet elevation measurements from the Sentinel-3A and Sentinel-3B tandem phase
Using ICESat-2 and Operation IceBridge altimetry for supraglacial lake depth retrievals
Brief communication: Mapping Greenland's perennial firn aquifers using enhanced-resolution L-band brightness temperature image time series
Quantifying spatiotemporal variability of glacier algal blooms and the impact on surface albedo in southwestern Greenland
Aerogeophysical characterization of an active subglacial lake system in the David Glacier catchment, Antarctica
Measuring the location and width of the Antarctic grounding zone using CryoSat-2
Brief Communication: Update on the GPS reflection technique for measuring snow accumulation in Greenland
Improved GNSS-R bi-static altimetry and independent digital elevation models of Greenland and Antarctica from TechDemoSat-1
Melt in Antarctica derived from Soil Moisture and Ocean Salinity (SMOS) observations at L band
Sentinel-3 Delay-Doppler altimetry over Antarctica
Assessment of altimetry using ground-based GPS data from the 88S Traverse, Antarctica, in support of ICESat-2
Dual-satellite (Sentinel-2 and Landsat 8) remote sensing of supraglacial lakes in Greenland
Coherent large beamwidth processing of radio-echo sounding data
Multi-channel and multi-polarization radar measurements around the NEEM site
Seasonal variations of the backscattering coefficient measured by radar altimeters over the Antarctic Ice Sheet
Recent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula
Benjamin J. Wallis, Anna E. Hogg, Yikai Zhu, and Andrew Hooper
The Cryosphere, 18, 4723–4742, https://doi.org/10.5194/tc-18-4723-2024, https://doi.org/10.5194/tc-18-4723-2024, 2024
Short summary
Short summary
The grounding line, where ice begins to float, is an essential variable to understand ice dynamics, but in some locations it can be challenging to measure with established techniques. Using satellite data and a new method, Wallis et al. measure the grounding line position of glaciers and ice shelves in the Antarctic Peninsula and find retreats of up to 16.3 km have occurred since the last time measurements were made in the 1990s.
Veit Helm, Alireza Dehghanpour, Ronny Hänsch, Erik Loebel, Martin Horwath, and Angelika Humbert
The Cryosphere, 18, 3933–3970, https://doi.org/10.5194/tc-18-3933-2024, https://doi.org/10.5194/tc-18-3933-2024, 2024
Short summary
Short summary
We present a new approach (AWI-ICENet1), based on a deep convolutional neural network, for analysing satellite radar altimeter measurements to accurately determine the surface height of ice sheets. Surface height estimates obtained with AWI-ICENet1 (along with related products, such as ice sheet height change and volume change) show improved and unbiased results compared to other products. This is important for the long-term monitoring of ice sheet mass loss and its impact on sea level rise.
Riley Culberg, Roger J. Michaelides, and Julie Z. Miller
The Cryosphere, 18, 2531–2555, https://doi.org/10.5194/tc-18-2531-2024, https://doi.org/10.5194/tc-18-2531-2024, 2024
Short summary
Short summary
Ice slabs enhance meltwater runoff from the Greenland Ice Sheet. Therefore, it is important to understand their extent and change in extent over time. We present a new method for detecting ice slabs in satellite radar data, which we use to map ice slabs at 500 m resolution across the entire ice sheet in winter 2016–2017. Our results provide better spatial coverage and resolution than previous maps from airborne radar and lay the groundwork for long-term monitoring of ice slabs from space.
Philipp Sebastian Arndt and Helen Amanda Fricker
EGUsphere, https://doi.org/10.5194/egusphere-2024-1156, https://doi.org/10.5194/egusphere-2024-1156, 2024
Short summary
Short summary
We develop a method for ice-sheet-scale retrieval of supraglacial meltwater depths using ICESat-2 photon data. We report results for two drainage basins in Greenland and Antarctica during two contrasting melt seasons, where our method reveals a total of 1249 lakes up to 25 m deep. The large volume and wide variety of accurate depth data that our method provides enables the development of data-driven models of meltwater volumes in satellite imagery.
Anne Braakmann-Folgmann, Andrew Shepherd, David Hogg, and Ella Redmond
The Cryosphere, 17, 4675–4690, https://doi.org/10.5194/tc-17-4675-2023, https://doi.org/10.5194/tc-17-4675-2023, 2023
Short summary
Short summary
In this study, we propose a deep neural network to map the extent of giant Antarctic icebergs in Sentinel-1 images automatically. While each manual delineation requires several minutes, our U-net takes less than 0.01 s. In terms of accuracy, we find that U-net outperforms two standard segmentation techniques (Otsu, k-means) in most metrics and is more robust to challenging scenes with sea ice, coast and other icebergs. The absolute median deviation in iceberg area across 191 images is 4.1 %.
Trystan Surawy-Stepney, Anna E. Hogg, Stephen L. Cornford, and David C. Hogg
The Cryosphere, 17, 4421–4445, https://doi.org/10.5194/tc-17-4421-2023, https://doi.org/10.5194/tc-17-4421-2023, 2023
Short summary
Short summary
The presence of crevasses in Antarctica influences how the ice sheet behaves. It is important, therefore, to collect data on the spatial distribution of crevasses and how they are changing. We present a method of mapping crevasses from satellite radar imagery and apply it to 7.5 years of images, covering Antarctica's floating and grounded ice. We develop a method of measuring change in the density of crevasses and quantify increased fracturing in important parts of the West Antarctic Ice Sheet.
Enze Zhang, Ginny Catania, and Daniel T. Trugman
The Cryosphere, 17, 3485–3503, https://doi.org/10.5194/tc-17-3485-2023, https://doi.org/10.5194/tc-17-3485-2023, 2023
Short summary
Short summary
Glacier termini are essential for studying why glaciers retreat, but they need to be mapped automatically due to the volume of satellite images. Existing automated mapping methods have been limited due to limited automation, lack of quality control, and inadequacy in highly diverse terminus environments. We design a fully automated, deep-learning-based method to produce termini with quality control. We produced 278 239 termini in Greenland and provided a way to deliver new termini regularly.
Mads Dømgaard, Kristian K. Kjeldsen, Flora Huiban, Jonathan L. Carrivick, Shfaqat A. Khan, and Anders A. Bjørk
The Cryosphere, 17, 1373–1387, https://doi.org/10.5194/tc-17-1373-2023, https://doi.org/10.5194/tc-17-1373-2023, 2023
Short summary
Short summary
Sudden releases of meltwater from glacier-dammed lakes can influence ice flow, cause flooding hazards and landscape changes. This study presents a record of 14 drainages from 2007–2021 from a lake in west Greenland. The time series reveals how the lake fluctuates between releasing large and small amounts of drainage water which is caused by a weakening of the damming glacier following the large events. We also find a shift in the water drainage route which increases the risk of flooding hazards.
Tian Li, Geoffrey J. Dawson, Stephen J. Chuter, and Jonathan L. Bamber
The Cryosphere, 17, 1003–1022, https://doi.org/10.5194/tc-17-1003-2023, https://doi.org/10.5194/tc-17-1003-2023, 2023
Short summary
Short summary
The Totten and Moscow University glaciers in East Antarctica have the potential to make a significant contribution to future sea-level rise. We used a combination of different satellite measurements to show that the grounding lines have been retreating along the fast-flowing ice streams across these two glaciers. We also found two tide-modulated ocean channels that might open new pathways for the warm ocean water to enter the ice shelf cavity.
Karla Boxall, Frazer D. W. Christie, Ian C. Willis, Jan Wuite, and Thomas Nagler
The Cryosphere, 16, 3907–3932, https://doi.org/10.5194/tc-16-3907-2022, https://doi.org/10.5194/tc-16-3907-2022, 2022
Short summary
Short summary
Using high-spatial- and high-temporal-resolution satellite imagery, we provide the first evidence for seasonal flow variability of land ice draining to George VI Ice Shelf (GVIIS), Antarctica. Ultimately, our findings imply that other glaciers in Antarctica may be susceptible to – and/or currently undergoing – similar ice-flow seasonality, including at the highly vulnerable and rapidly retreating Pine Island and Thwaites glaciers.
Thomas R. Chudley, Ian M. Howat, Bidhyananda Yadav, and Myoung-Jong Noh
The Cryosphere, 16, 2629–2642, https://doi.org/10.5194/tc-16-2629-2022, https://doi.org/10.5194/tc-16-2629-2022, 2022
Short summary
Short summary
Sentinel-2 images are subject to distortion due to orthorectification error, which makes it difficult to extract reliable glacier velocity fields from images from different orbits. Here, we use a complete record of velocity fields at four Greenlandic outlet glaciers to empirically estimate the systematic error, allowing us to correct cross-track glacier velocity fields to a comparable accuracy to other medium-resolution satellite datasets.
Weiran Li, Cornelis Slobbe, and Stef Lhermitte
The Cryosphere, 16, 2225–2243, https://doi.org/10.5194/tc-16-2225-2022, https://doi.org/10.5194/tc-16-2225-2022, 2022
Short summary
Short summary
This study proposes a new method for correcting the slope-induced errors in satellite radar altimetry. The slope-induced errors can significantly affect the height estimations of ice sheets if left uncorrected. This study applies the method to radar altimetry data (CryoSat-2) and compares the performance with two existing methods. The performance is assessed by comparison with independent height measurements from ICESat-2. The assessment shows that the method performs promisingly.
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
Short summary
Short summary
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.
Rajashree Tri Datta and Bert Wouters
The Cryosphere, 15, 5115–5132, https://doi.org/10.5194/tc-15-5115-2021, https://doi.org/10.5194/tc-15-5115-2021, 2021
Short summary
Short summary
The ICESat-2 laser altimeter can detect the surface and bottom of a supraglacial lake. We introduce the Watta algorithm, automatically calculating lake surface, corrected bottom, and (sub-)surface ice at high resolution adapting to signal strength. ICESat-2 depths constrain full lake depths of 46 lakes over Jakobshavn glacier using multiple sources of imagery, including very high-resolution Planet imagery, used for the first time to extract supraglacial lake depths empirically using ICESat-2.
Helmut Rott, Stefan Scheiblauer, Jan Wuite, Lukas Krieger, Dana Floricioiu, Paola Rizzoli, Ludivine Libert, and Thomas Nagler
The Cryosphere, 15, 4399–4419, https://doi.org/10.5194/tc-15-4399-2021, https://doi.org/10.5194/tc-15-4399-2021, 2021
Short summary
Short summary
We studied relations between interferometric synthetic aperture radar (InSAR) signals and snow–firn properties and tested procedures for correcting the penetration bias of InSAR digital elevation models at Union Glacier, Antarctica. The work is based on SAR data of the TanDEM-X mission, topographic data from optical sensors and field measurements. We provide new insights on radar signal interactions with polar snow and show the performance of penetration bias retrievals using InSAR coherence.
Malcolm McMillan, Alan Muir, and Craig Donlon
The Cryosphere, 15, 3129–3134, https://doi.org/10.5194/tc-15-3129-2021, https://doi.org/10.5194/tc-15-3129-2021, 2021
Short summary
Short summary
We evaluate the consistency of ice sheet elevation measurements made by two satellites: Sentinel-3A and Sentinel-3B. We analysed data from the unique
tandemphase of the mission, where the two satellites flew 30 s apart to provide near-instantaneous measurements of Earth's surface. Analysing these data over Antarctica, we find no significant difference between the satellites, which is important for demonstrating that they can be used interchangeably for long-term ice sheet monitoring.
Zachary Fair, Mark Flanner, Kelly M. Brunt, Helen Amanda Fricker, and Alex Gardner
The Cryosphere, 14, 4253–4263, https://doi.org/10.5194/tc-14-4253-2020, https://doi.org/10.5194/tc-14-4253-2020, 2020
Short summary
Short summary
Ice on glaciers and ice sheets may melt and pond on ice surfaces in summer months. Detection and observation of these meltwater ponds is important for understanding glaciers and ice sheets, and satellite imagery has been used in previous work. However, image-based methods struggle with deep water, so we used data from the Ice, Clouds, and land Elevation Satellite-2 (ICESat-2) and the Airborne Topographic Mapper (ATM) to demonstrate the potential for lidar depth monitoring.
Julie Z. Miller, David G. Long, Kenneth C. Jezek, Joel T. Johnson, Mary J. Brodzik, Christopher A. Shuman, Lora S. Koenig, and Ted A. Scambos
The Cryosphere, 14, 2809–2817, https://doi.org/10.5194/tc-14-2809-2020, https://doi.org/10.5194/tc-14-2809-2020, 2020
Shujie Wang, Marco Tedesco, Patrick Alexander, Min Xu, and Xavier Fettweis
The Cryosphere, 14, 2687–2713, https://doi.org/10.5194/tc-14-2687-2020, https://doi.org/10.5194/tc-14-2687-2020, 2020
Short summary
Short summary
Glacial algal blooms play a significant role in darkening the Greenland Ice Sheet during summertime. The dark pigments generated by glacial algae could substantially reduce the bare ice albedo and thereby enhance surface melt. We used satellite data to map the spatial distribution of glacial algae and characterized the seasonal growth pattern and interannual trends of glacial algae in southwestern Greenland. Our study is important for bridging microbial activities with ice sheet mass balance.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Kristine M. Larson, Michael MacFerrin, and Thomas Nylen
The Cryosphere, 14, 1985–1988, https://doi.org/10.5194/tc-14-1985-2020, https://doi.org/10.5194/tc-14-1985-2020, 2020
Short summary
Short summary
Reflected GPS signals can be used to measure snow accumulation. The GPS method is accurate and has a footprint that is larger than that of many other methods. This short note makes available 9 years of daily snow accumulation measurements from Greenland that were derived from reflected GPS signals. It also provides information about open-source software that the cryosphere community can use to analyze other datasets.
Jessica Cartwright, Christopher J. Banks, and Meric Srokosz
The Cryosphere, 14, 1909–1917, https://doi.org/10.5194/tc-14-1909-2020, https://doi.org/10.5194/tc-14-1909-2020, 2020
Short summary
Short summary
This study uses reflected GPS signals to measure ice at the South Pole itself for the first time. These measurements are essential to understand the interaction of the ice with the Earth’s physical systems. Orbital constraints mean that satellites are usually unable to measure in the vicinity of the South Pole itself. This is overcome here by using data obtained by UK TechDemoSat-1. Data are processed to obtain the height of glacial ice across the Greenland and Antarctic ice sheets.
Marion Leduc-Leballeur, Ghislain Picard, Giovanni Macelloni, Arnaud Mialon, and Yann H. Kerr
The Cryosphere, 14, 539–548, https://doi.org/10.5194/tc-14-539-2020, https://doi.org/10.5194/tc-14-539-2020, 2020
Short summary
Short summary
To study the coast and ice shelves affected by melt in Antarctica during the austral summer, we exploited the 1.4 GHz radiometric satellite observations. We showed that this frequency provides additional information on melt occurrence and on the location of the water in the snowpack compared to the 19 GHz observations. This opens an avenue for improving the melting season monitoring with a combination of both frequencies and exploring the possibility of deep-water detection in the snowpack.
Malcolm McMillan, Alan Muir, Andrew Shepherd, Roger Escolà, Mònica Roca, Jérémie Aublanc, Pierre Thibaut, Marco Restano, Américo Ambrozio, and Jérôme Benveniste
The Cryosphere, 13, 709–722, https://doi.org/10.5194/tc-13-709-2019, https://doi.org/10.5194/tc-13-709-2019, 2019
Short summary
Short summary
Melting of the Greenland and Antarctic ice sheets is one of the main causes of current sea level rise. Understanding ice sheet change requires large-scale systematic satellite monitoring programmes. This study provides the first assessment of a new long-term source of measurements, from Sentinel-3 satellite altimetry. We estimate the accuracy of Sentinel-3 across Antarctica, show that the satellite can detect regions that are rapidly losing ice, and identify signs of subglacial lake activity.
Kelly M. Brunt, Thomas A. Neumann, and Christopher F. Larsen
The Cryosphere, 13, 579–590, https://doi.org/10.5194/tc-13-579-2019, https://doi.org/10.5194/tc-13-579-2019, 2019
Short summary
Short summary
This paper provides an assessment of new GPS elevation data collected near the South Pole, Antarctica, that will ultimately be used for ICESat-2 satellite elevation data validation. Further, using the new ground-based GPS data, this paper provides an assessment of airborne lidar elevation data collected between 2014 and 2017, which will also be used for ICESat-2 data validation.
Andrew G. Williamson, Alison F. Banwell, Ian C. Willis, and Neil S. Arnold
The Cryosphere, 12, 3045–3065, https://doi.org/10.5194/tc-12-3045-2018, https://doi.org/10.5194/tc-12-3045-2018, 2018
Short summary
Short summary
A new approach is presented for automatically monitoring changes to area and volume of surface lakes on the Greenland Ice Sheet using Landsat 8 and Sentinel-2 satellite data. The dual-satellite record improves on previous work since it tracks changes to more lakes (including small ones), identifies more lake-drainage events, and has higher precision. The results also show that small lakes are important in ice-sheet hydrology as they route more surface run-off into the ice sheet than large lakes.
Anton Heister and Rolf Scheiber
The Cryosphere, 12, 2969–2979, https://doi.org/10.5194/tc-12-2969-2018, https://doi.org/10.5194/tc-12-2969-2018, 2018
Short summary
Short summary
We provide a method based on Fourier analysis of coherent radio-echo sounding data for analyzing angular back-scattering characteristics of the ice sheet and bed. The characteristics can be used for the bed roughness estimation and detection of subglacial water. The method also offers improved estimation of the internal layers' tilt. The research is motivated by a need for a tool for training dictionaries for model-based tomographic focusing of multichannel coherent radio-echo sounders.
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
Short summary
Short summary
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.
Fifi Ibrahime Adodo, Frédérique Remy, and Ghislain Picard
The Cryosphere, 12, 1767–1778, https://doi.org/10.5194/tc-12-1767-2018, https://doi.org/10.5194/tc-12-1767-2018, 2018
Short summary
Short summary
In Antarctica, the seasonal cycle of the backscatter behaves differently at high and low frequencies, peaking in winter and in summer, respectively. At the intermediate frequency, some areas behave analogously to low frequency in terms of the seasonal cycle, but other areas behave analogously to high frequency. This calls into question the empirical relationships often used to correct elevation changes from radar penetration into the snowpack using backscatter.
Peter Friedl, Thorsten C. Seehaus, Anja Wendt, Matthias H. Braun, and Kathrin Höppner
The Cryosphere, 12, 1347–1365, https://doi.org/10.5194/tc-12-1347-2018, https://doi.org/10.5194/tc-12-1347-2018, 2018
Short summary
Short summary
Fleming Glacier is the biggest tributary glacier of the former Wordie Ice Shelf. Radar satellite data and airborne ice elevation measurements show that the glacier accelerated by ~27 % between 2008–2011 and that ice thinning increased by ~70 %. This was likely a response to a two-phase ungrounding of the glacier tongue between 2008 and 2011, which was mainly triggered by increased basal melt during two strong upwelling events of warm circumpolar deep water.
Cited articles
Bamber, J. and Gomez-Dans, J. L.: The accuracy of digital elevation models
of the Antarctic continent, Earth Planet. Sc. Lett., 237, 3–4,
516–523, 2005.
Cook, A. J., Murray, T., Luckman, A., Vaughan, D. G., and Barrand, N. E.:
A new 100-m Digital Elevation Model of the Antarctic Peninsula derived from
ASTER Global DEM: methods and accuracy assessment, Earth Syst. Sci. Data,
4, 129–142, https://doi.org/10.5194/essd-4-129-2012, 2012.
DiMarzio, J., Brenner, A., Schutz, R., Shuman, C. A., and Zwally, H. J.:
GLAS/ICESat 500 m laser altimetry digital elevation model of Antarctica.
Boulder, Colorado USA: National Snow and Ice Data Center, Digital media,
https://doi.org/10.5067/K2IMI0L24BRJ, 2007.
Fretwell, P., Pritchard, H. D., Vaughan, D. G., Bamber, J. L., Barrand, N.
E., Bell, R., Bianchi, C., Bingham, R. G., Blankenship, D. D., Casassa, G.,
Catania, G., Callens, D., Conway, H., Cook, A. J., Corr, H. F. J., Damaske,
D., Damm, V., Ferraccioli, F., Forsberg, R., Fujita, S., Gim, Y., Gogineni,
P., Griggs, J. A., Hindmarsh, R. C. A., Holmlund, P., Holt, J. W., Jacobel,
R. W., Jenkins, A., Jokat, W., Jordan, T., King, E. C., Kohler, J., Krabill,
W., Riger-Kusk, M., Langley, K. A., Leitchenkov, G., Leuschen, C., Luyendyk,
B. P., Matsuoka, K., Mouginot, J., Nitsche, F. O., Nogi, Y., Nost, O. A.,
Popov, S. V., Rignot, E., Rippin, D. M., Rivera, A., Roberts, J., Ross, N.,
Siegert, M. J., Smith, A. M., Steinhage, D., Studinger, M., Sun, B., Tinto,
B. K., Welch, B. C., Wilson, D., Young, D. A., Xiangbin, C., and Zirizzotti,
A.: Bedmap2: improved ice bed, surface and thickness datasets for Antarctica,
The Cryosphere, 7, 375–393, https://doi.org/10.5194/tc-7-375-2013, 2013.
Gray, L., Burgess, D., Copland, L., Dunse, T., Langley, K., and Moholdt, G.:
A revised calibration of the interferometric mode of the CryoSat-2 radar
altimeter improves ice height and height change measurements in western
Greenland, The Cryosphere, 11, 1041–1058,
https://doi.org/10.5194/tc-11-1041-2017, 2017.
Griggs, J. A. and Bamber, J. L.: A new 1 km digital elevation model of
Antarctica derived from combined radar and laser data – Part 2: Validation
and error estimates, The Cryosphere, 3, 113–123,
https://doi.org/10.5194/tc-3-113-2009, 2009.
Hasewaga, H., Matsuo, K., Koarai, M., Watanabe, N., Masaharu, H., and
Fukushima, Y.: DEM accuracy and the base to height (B/H) ratio of stereo
images, paper presented at Proceedings of the 19th ISPRS Congress, Amsterdam,
2000.
Helm, V., Humbert, A., and Miller, H.: Elevation and elevation change of
Greenland and Antarctica derived from CryoSat-2, The Cryosphere, 8,
1539–1559, https://doi.org/10.5194/tc-8-1539-2014, 2014.
Hofton, M. A., Blair, J. B., Luthcke, S. B., and Rabine, D. L.: Assessing the
performance of 20–25 m footprint waveform lidar data collected in ICESat
data corridors in Greenland, Geophys. Res. Lett., 35, L24501,
https://doi.org/10.1029/2008gl035774, 2008.
Howat, I., Morin, P., Porter, C., and Noh, M.-J.: The Reference Elevation Model of Antarctica,
https://doi.org/10.7910/DVN/SAIK8B, Harvard Dataverse, V1 (last access: 22 February 2019), 2018
Levinsen, J. F., Howat, I. M., and Tscherning, C. C.: Improving maps of
ice-sheet surface elevation change using combined laser altimeter and
stereoscopic elevation model data, J. Glaciol., 59, 524–532,
https://doi.org/10.3189/2013JoG12J114, 2013.
Martin, C. F., Krabill, W. B., Manizade, S., Russell, R., Sonntag, J. G.,
Swift, R. N., and Yungel, J. K.: Airborne Topographic Mapper Calibration
Procedures and Accuracy Assessment, Rep. 20120008479 (NASA/TM-2012-215891,
GSFC.TM.5893.2012), Natl. Aeronaut. and Space Admin., Washington, D.C., 2012.
Noh, M. and Howat, I. M.: Automated stereo-photogrammetric DEM generation at
high latitudes: Surface Extraction with TIN-based Search-space Minimization
(SETSM) validation and demonstration over glaciated regions, Gisci. Remote
Sens., 52, 198–217, https://doi.org/10.1080/15481603.2015.1008621, 2015.
Noh, M. and Howat, I. M.: The Surface Extraction from TIN based Search-space
Minimization (SETSM) algorithm, ISPRS J. Photogramm., 129, 55–76,
https://doi.org/10.1016/j.isprsjprs.2017.04.019, 2017.
Nuth, C. and Kääb, A.: Co-registration and bias corrections of
satellite elevation data sets for quantifying glacier thickness change, The
Cryosphere, 5, 271–290, https://doi.org/10.5194/tc-5-271-2011, 2011.
Shean, D. E., Alexandrov, O., Moratto, Z. M., Smith, B. E., Joughin, I. R.,
Porter, C., and Morin, P.: An automated, open-source pipeline for mass
production of digital elevation models (DEMs) from very-high-resolution
commercial stereo satellite imagery, ISPRS J. Photogramm., 116, 101–117,
https://doi.org/10.1016/j.isprsjprs.2016.03.012, 2016.
Shuman, C. A., Zwally, H. J., Schutz, B. E., Brenner, A. C., DiMarzio, J. P.,
Suchdeo, V. P., and Fricker, H. A.: ICESat Antarctic elevation data:
Preliminary precision and accuracy assessment, Geophys. Res. Lett., 33,
L07501, https://doi.org/10.1029/2005GL025227, 2006.
Slater, T., Shepherd, A., McMillan, M., Muir, A., Gilbert, L., Hogg, A. E.,
Konrad, H., and Parrinello, T.: A new digital elevation model of Antarctica
derived from CryoSat-2 altimetry, The Cryosphere, 12, 1551–1562,
https://doi.org/10.5194/tc-12-1551-2018, 2018.
Wang, F., Bamber, J. L., and Cheng, X.: Accuracy and Performance of
CryoSat-2 SARIn Mode Data Over Antarctica, IEEE Geosci. Remote S., 12,
1516–1520, https://doi.org/10.1109/LGRS.2015.2411434, 2015.
Wessel, B., Huber, M., Wohlfart, C., Marschalk, U., Kosmann, D., and Roth,
A.: Accuracy Assessment of the Global TanDEM-X Digital Elevation Model with
GPS Data, ISPRS J. Photogramm., 139, 171–182, 2018.
Young, D. A., Lindzey, L. E., Blankenship, D. D., Greenbaum, J. S., de
Gorord, A. G., Kempf, S. D., Roberts, J. L., Warner, R. C., Van Ommen, T.,
Siegert, M. J., and Le Meur, E.: Land-ice elevation changes from
photon-counting swath altimetry: first applications over the Antarctic ice
sheet, J. Glaciol., 61, 17–28, https://doi.org/10.3189/2015JoG14J048, 2015.
Zwally, H. J., Schutz, R., Hancock, D., and DiMarzio, J.: GLAS/ICESat L2
Antarctic and Greenland Ice Sheet Altimetry Data (HDF5), Version 34. Boulder,
Colorado USA, NASA National Snow and Ice Data Center Distributed Active
Archive Center, https://doi.org/10.5067/ICESAT/GLAS/DATA209, 2014.
Short summary
The Reference Elevation Model of Antarctica (REMA) is the first continental-scale terrain map at less than 10 m resolution, and the first with a time stamp, enabling measurements of elevation change. REMA is constructed from over 300 000 individual stereoscopic elevation models (DEMs) extracted from submeter-resolution satellite imagery. REMA is vertically registered to satellite altimetry, resulting in errors of less than 1 m over most of its area and relative uncertainties of decimeters.
The Reference Elevation Model of Antarctica (REMA) is the first continental-scale terrain map at...
