Article
Multidisciplinary Sciences
Chengfei He, Zhengyu Liu, Bette L. Otto-Bliesner, Esther C. Brady, Chenyu Zhu, Robert Tomas, Christo Buizert, Jeffrey P. Severinghaus
Summary: The research suggests that the Greenland ice core oxygen isotope O-18 records may significantly underestimate temperature variability during cold glacial conditions, as a substantial cooling in the Arctic during winter and warming in summer occurred. This discrepancy is attributed to the loss of winter precipitation due to sea ice expansion.
Article
Geosciences, Multidisciplinary
Jacqueline Otto, Felicity A. Holmes, Nina Kirchner
Summary: This study presents recent changes in supraglacial lake distribution, expansion, drainage behavior, and frequency in Ryder Glacier, Northern Greenland, using remote sensing analysis. The results show that increasing global temperatures lead to inland expansion of supraglacial lakes and their impact on larger areas of the ice sheet. However, due to limited understanding of the dynamics of lake expansion, assessments of future implications remain uncertain.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
J. Z. Mejia, J. D. Gulley, C. Trunz, M. D. Covington, T. C. Bartholomaus, S. Xie, T. H. Dixon
Summary: Seasonal variability in Greenland Ice Sheet's sliding speed is mainly regulated by the response of the subglacial drainage system to meltwater inputs. Analysis of measurements shows that the dewatering of isolated cavities leads to an increase in basal traction, causing the ice deceleration. Therefore, the dewatering of isolated parts of the subglacial drainage system plays a key role in driving seasonal slowdowns on the Greenland Ice Sheet.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Aslak Grinsted, Christine S. Hvidberg, David A. Lilien, Nicholas M. Rathmann, Nanna B. Karlsson, Tamara Gerber, Helle Astrid Kjaer, Paul Vallelonga, Dorthe Dahl-Jensen
Summary: A new study reveals the instability of the North East Greenland ice stream and its potential impact on future evolution. By analyzing remote sensing data and GPS observations, researchers find that the shear margins of the ice stream are accelerating and widening, which is likely due to the softening of the shear margin caused by evolving fabric or temperature, rather than external forcing.
NATURE COMMUNICATIONS
(2022)
Article
Geography, Physical
Kristin Poinar, Lauren C. Andrews
Summary: This study used remote-sensing data to analyze the relationship between strain rates and lake drainages in western Greenland. The study found that moulins associated with fast-draining lakes have significantly higher extensional background strain rates. However, the current ice sheet velocity products cannot accurately resolve the transient strain rates that drive fast lake drainages.
Article
Geography, Physical
Yubin Fan, Chang-Qing Ke, Xiaoyi Shen, Yao Xiao, Stephen J. J. Livingstone, Andrew J. J. Sole
Summary: Using ICESat-2 data, we identified 18 active subglacial lakes, 16 of which had not been previously reported. By utilizing multi-temporal ArcticDEM strip maps, we verified the existence of these lakes and determined their drainage history. After correcting the elevation data, significant localized elevation anomalies were measured in all detected subglacial lakes, demonstrating the potential of combining ICESat-2 and ArcticDEM.
Article
Multidisciplinary Sciences
Ching-Yao Lai, Laura A. Stevens, Danielle L. Chase, Timothy T. Creyts, Mark D. Behn, Sarah B. Das, Howard A. Stone
Summary: Research on the Greenland Ice Sheet shows that the basal hydrology undergoes significant changes beneath glacier lakes as the melt season progresses. By studying surface uplift relaxation following rapid lake drainage events, researchers have discovered a universal relaxation law that indicates a two-order-of-magnitude increase in subglacial transmissivity. This suggests that seasonal meltwater input drives substantial changes in basal hydrology beneath lakes.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
David M. Chandler, Jemma L. Wadham, Peter W. Nienow, Samuel H. Doyle, Andrew J. Tedstone, Jon Telling, Jonathan Hawkings, Jonathan D. Alcock, Benjamin Linhoff, Alun Hubbard
Summary: Intensive study of the Greenland Ice Sheet's subglacial drainage has shown efficient drainage development under thick ice, with this research providing valuable data to validate and improve current numerical drainage system models. The study revealed a fast/efficient subglacial drainage system extending under ice over 900m thick, which remained stable even under variable melt inputs. This research emphasizes the importance of understanding subglacial drainage dynamics in the context of ice dynamics and hydrology.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geography, Physical
Rajashree Tri Datta, Bert Wouters
Summary: The algorithm introduced in this study, named Watta, automatically calculates supraglacial lake bathymetry and detects potential ice layers. By utilizing multiple satellite imagery sources and altimetry-based depths from ICESat-2, it can improve the spatial and temporal scales of capturing the evolution of supraglacial hydrology.
Article
Multidisciplinary Sciences
Laura A. Stevens, Meredith Nettles, James L. Davis, Timothy T. Creyts, Jonathan Kingslake, Ian J. Hewitt, Aaron Stubblefield
Summary: The impact of increasing surface melt on the annual discharge of the Greenland Ice Sheet is unclear. Observations of a supraglacial lake drainage at Helheim Glacier show that basal floods following these events have limited effect on ice flow. The discharge of the ice sheet to the ocean is mainly controlled by fast-flowing outlet glaciers, and the influence of increasing surface melt on annual discharge is still unknown.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
Steven Franke, Daniela Jansen, Sebastian Beyer, Niklas Neckel, Tobias Binder, John Paden, Olaf Eisen
Summary: The study evaluates the basal conditions of the onset region of the Northeast Greenland Ice Stream (NEGIS) using airborne ultra-wideband radar data, revealing changes in basal roughness and anisotropy in subglacial structures. In the upstream area, excess ice mass flux is evacuated through ice flow acceleration, while the downstream part shows rougher bed topography and decreased flow acceleration. This suggests two distinct zones in the NEGIS: one collecting water with reduced basal traction, and one where the ice stream slows down and widens on a rougher bed with basal water distributed towards shear margins.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
Nathan Maier, Jonas Kvist Andersen, Jeremie Mouginot, Florent Gimbert, Olivier Gagliardini
Summary: Surface melt can cause ice-flow accelerations on glaciers and ice sheets in both summer and winter. In this study, researchers have found that winter meltwater-induced accelerations occur in Greenland as well. They observed supraglacial lakes draining at high elevation, leading to a significant increase in flow velocity over a large region. By analyzing the surface velocity field and flood propagation, they gained novel insights into subglacial water pathways, drainage morphology, and basal sliding. These events are likely common and their cumulative impact on glacier dynamics needs further evaluation.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geography, Physical
Karol Tylmann, Szymon Uscinowicz
Summary: A new chronology of the last retreat of the Scandinavian Ice Sheet in the southern Baltic basin is proposed, based on Bayesian age modeling. The study shows that the retreat rates of the ice margin did not accelerate after the formation of an ice-dammed lake, suggesting that the ice margin was grounded and prevented from rapid retreat. The timing of the retreat phases corresponds to climatic fluctuations in the Northern Hemisphere.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Aaron K. Medford, Brenda L. Hall, Thomas V. Lowell, Meredith A. Kelly, Laura B. Levy, Paul S. Wilcox, Yarrow Axford
Summary: The record of Renland Ice Cap shows rapid glacier fluctuation over the past 12,000 years, indicating a close relationship between glacier activity and climate change. The findings suggest that understanding ice variations in a region requires examination of multiple geographic and geomorphologic settings.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geography, Physical
Ross Maguire, Nicholas Schmerr, Erin Pettit, Kiya Riverman, Christyna Gardner, Daniella N. DellaGiustina, Brad Avenson, Natalie Wagner, Angela G. Marusiak, Namrah Habib, Juliette Broadbeck, Veronica J. Bray, Samuel H. Bailey
Summary: The study reports the results of a seismic and ground-penetrating radar survey in northwestern Greenland, which indicates the presence of a subglacial lake approximately 830-845m below the surface. The lake is estimated to be 10-15m deep, with hypotheses for its origin narrowed down to anomalously high geothermal flux or hypersalinity based on thermal and hydropotential modeling.
Article
Multidisciplinary Sciences
Malin E. Kylander, A. Martinez-Cortizas, Richard Bindler, Joeri Kaal, Jenny K. Sjostrom, Sophia V. Hansson, Noemi Silva-Sanchez, Sarah L. Greenwood, Kerry Gallagher, Johan Rydberg, Carl-Magnus Morth, Sebastien Rauch
SCIENTIFIC REPORTS
(2018)
Article
Multidisciplinary Sciences
Sarah L. Greenwood, Lauren M. Simkins, Anna Ruth W. Halberstadt, Lindsay O. Prothro, John B. Anderson
NATURE COMMUNICATIONS
(2018)
Article
Geography, Physical
Calvin Shackleton, Henry Patton, Alun Hubbard, Monica Winsborrow, Jonathan Kingslake, Mariana Esteves, Karin Andreassen, Sarah L. Greenwood
QUATERNARY SCIENCE REVIEWS
(2018)
Article
Geography, Physical
Rachael S. Avery, Sarah L. Greenwood, Frederik Schenk, Bjorn M. Moren, David I. Armstrong Mckay, Lars Brunnberg, Barbara Wohlfarth
Summary: The Swedish Varve Chronology is a valuable tool for studying the deglacial history and associated palaeo-environmental change on an annual time scale. By revisiting varve chronologies in southern Sweden and analyzing new data, researchers have refined and extended the existing chronology, revealing important details about ice-margin dynamics and climate change connections. The 725-year-long varve thickness series shows repeated episodes of increased sedimentation, likely indicating phases of enhanced ice-sheet melting throughout the deglaciation of Skane-Smaland.
Article
Multidisciplinary Sciences
Sarah L. Greenwood, Lauren M. Simkins, Monica C. M. Winsborrow, Lilja R. Bjarnadottir
Summary: Projections of ice sheet behavior rely on the evolution of ice flow velocity and stability of marine-based grounding lines. The relationship between ice flow and underlying terrain determines retreat styles, with exceptions to expected behavior including regional topographic highs not always hindering fast ice flow and retreat proceeding steadily on reverse slopes. Ice streaming is not necessarily favored on specific geological substrates, and readvance is rarely observed once grounding line retreat has begun, regardless of regional bed characteristics.
Article
Geography, Physical
Dominik Fahrner, James M. Lea, Stephen Brough, Douglas W. F. Mair, Jakob Abermann
Summary: The study shows that tidewater glacier margins in different regions of the Greenland ice sheet exhibit linear retreat trends, with varying sensitivity to climate drivers. While most glaciers experience retreat, the observed increase in absolute flux for the entire ice sheet is primarily influenced by a small number of glaciers.
JOURNAL OF GLACIOLOGY
(2021)
Article
Environmental Sciences
Amelia B. Vale, Neil S. Arnold, W. Gareth Rees, James M. Lea
Summary: The research utilized cloud-based geospatial data platform and tools to systematically study the distribution and characteristics of surging glaciers in the High Mountain Asia region, identifying 137 surging glaciers. Through terminal position time series analysis, glacier behavior was classified, and surge variables were quantified, highlighting the importance of surging glaciers in geohazard monitoring.
Article
Geosciences, Multidisciplinary
L. M. Simkins, S. L. Greenwood, S. Munevar Garcia, E. A. Eareckson, J. B. Anderson, L. O. Prothro
Summary: A study on a relict subglacial meltwater corridor on the Antarctic continental shelf reveals significant variations in drainage capacity due to basal water additions and losses related to bed topography. The channel system's behavior is influenced by the shape of the underlying terrain, with larger retreat events occurring while the system was active. This demonstrates the complex interactions between subglacial water drainage and bed topography, highlighting their prolonged impacts on grounding-line behavior.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Jonathan L. Carrivick, Penelope How, James M. Lea, Jenna L. Sutherland, Michael Grimes, Fiona S. Tweed, Stephen Cornford, Duncan J. Quincey, Joseph Mallalieu
Summary: Ice-marginal lakes have a significant impact on glacier dynamics, but have been overlooked in studies on the Greenland ice sheet and peripheral glaciers. This study finds that lakes cover 10% of the Greenland ice margin and occur on 5% of peripheral glaciers. Ice velocity at lakes is around 25% higher than on land.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geography, Physical
Sophie Goliber, Taryn Black, Ginny Catania, James M. Lea, Helene Olsen, Daniel Cheng, Suzanne Bevan, Anders Bjork, Charlie Bunce, Stephen Brough, J. Rachel Carr, Tom Cowton, Alex Gardner, Dominik Fahrner, Emily Hill, Ian Joughin, Niels J. Korsgaard, Adrian Luckman, Twila Moon, Tavi Murray, Andrew Sole, Michael Wood, Enze Zhang
Summary: In this study, a database of manually digitized terminus traces is presented for machine learning and scientific applications. The dataset includes 39,060 individual terminus traces for 278 glaciers, which have been collected, cleaned, and assigned with appropriate metadata for easy access by scientists.
Article
Geography, Physical
David W. Ashmore, Douglas W. F. Mair, Jonathan E. Higham, Stephen Brough, James M. Lea, Isabel J. Nias
Summary: This study applies the POD technique to analyze an ice velocity dataset from Sermeq Kujalleq in Greenland, finding three dominant modes related to glaciological processes. The primary dominant mode is associated with stress reconfiguration at the glacier terminus, while the second and third modes are linked to the development of the glacier's hydrological system.
Article
Geography, Physical
Peter A. Tuckett, Jeremy C. Ely, Andrew J. Sole, James M. Lea, Stephen J. Livingstone, Julie M. Jones, J. Melchior van Wessem
Summary: Research shows high interannual variability in surface meltwater cover in Antarctica, with the new method providing reliable spatiotemporal data. By incorporating image visibility assessments, more accurate estimates of surface meltwater area can be obtained, and predictions from regional climate models can effectively reflect actual conditions.
Article
Geology
Pedro Preto, Christian Stranne, Sarah Greenwood, Martin Jakobsson, Jens-Ove Naslund, Jan Sundberg, Henrik Sward, Matt O'Regan
Article
Meteorology & Atmospheric Sciences
Martin Jakobsson, Christian Stranne, Matt O'Regan, Sarah L. Greenwood, Bo Gustafsson, Christoph Humborg, Elizabeth Weidner
Article
Geography, Physical
Henrik Sward, Matt O'Regan, Svante Bjorck, Sarah L. Greenwood, Malin E. Kylander, Carl-Magnus Morth, Christof Pearce, Martin Jakobsson