Article
Geosciences, Multidisciplinary
Isabel J. Nias, Sophie Nowicki, Denis Felikson, Bryant Loomis
Summary: Mass loss from the Greenland Ice Sheet is a combination of surface mass balance and discharge due to ice dynamics. Perturbations to glacier termini result in immediate velocity and mass loss, as well as a diffusive response over time due to ice thickness evolution. Modeling the committed response of the ice sheet can provide estimates of its contribution to future sea level rise.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2023)
Article
Oceanography
Daniel N. Goldberg, Andrew G. Twelves, Paul R. Holland, Martin G. Wearing
Summary: Little is known about Antarctic subglacial hydrology, but it is believed that subglacial runoff enhances submarine melt locally through buoyancy effects. This study examines the effects of runoff on sea ice and oceanography on the Continental Shelf, and finds that runoff enhances localized melt and reduces summer sea ice volume. Runoff-driven melt and circulation may be an important missing process in regional Antarctic ocean models.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Letter
Geosciences, Multidisciplinary
N. Jullien, A. J. Tedstone, H. Machguth, N. B. Karlsson, V. Helm
Summary: We analyzed airborne accumulation radar data from 2002 to 2018 to investigate changes in the extent and thickness of ice slabs in Greenland. It was found that ice slabs several meters thick were already present before 2002. Between 2012 and 2018, the ice slabs expanded inland by 13,400-17,600 km(2), or 37%-44%. The study also demonstrated that the extremely warm summer of 2012 led to the formation of near-surface ice layers at higher elevations, enabling the development of ice slabs with only moderate melting in subsequent summers.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Oceanography
Theresa J. Morrison, Dmitry S. Dukhovskoy, Julie L. McClean, Sarah T. Gille, Eric P. Chassignet
Summary: The presence of warm Atlantic water on the Greenland continental shelf is connected to the accelerated melting of the Greenland Ice Sheet. This study uses high-resolution simulations to understand the flux of heat on and off the southern Greenland shelf. The results show that the southeast region of Greenland has the greatest heat flux onto the shelf, while the southwestern region mainly exports heat from the shelf to the interior basins.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Multidisciplinary Sciences
P. A. Reid, R. A. Massom
Summary: Loss of protective sea-ice buffer in Antarctica has led to increased exposure of the coastal environment to open ocean and waves, which has significant effects on ice-shelf stability, coastal erosion, ice-ocean-atmosphere interactions, and shallow benthic ecosystems. Researchers have introduced a climate and environmental metric called Coastal Exposure Length, which measures the daily changes and variability in the length and occurrence of unprotected coastline in Antarctica. The study found that around 50% of Antarctica's 17,850-km coastline had no sea ice offshore each summer, with variations in exposure levels across regions and seasons. From 1979 to 2020, the annual maximum length of coastal exposure decreased by approximately 30 km per year.
NATURE COMMUNICATIONS
(2022)
Article
Geography, Physical
Kazuya Kusahara, Daisuke Hirano, Masakazu Fujii, Alexander D. Fraser, Takeshi Tamura
Summary: This study investigates the basal melting of Antarctic ice shelves in different regions using simulation methods, revealing the mechanisms and seasonal variations of CDW intrusion in different regions of Antarctica, and discussing the impact of fast ice on the marine environment in the bay.
Article
Geochemistry & Geophysics
Genti Toyokuni, Masanao Komatsu, Hiroshi Takenaka
Summary: The study estimated the seismic attenuation of the Greenland Ice Sheet by comparing observed and theoretical Rayleigh waveforms, revealing a low Q factor of 10-50 and indicating high attenuation of seismic waves due to ice. The obtained Q factors are essential for estimating the thermal state and density distribution of the ice sheet, as well as interpreting the characteristics of seismic waveforms propagating through it.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geography, Physical
Andreas Born, Alexander Robinson
Summary: This study presents the first three-dimensional ice sheet model that explicitly simulates the Greenland englacial stratigraphy, which can greatly aid in model calibration, improving past and future sea level estimates, and providing insights into past ice sheet dynamics. The isochronal advection scheme in the model produces a more reliable simulation of englacial age profile than traditional age tracers, showing notably more accurate results when compared with dated radiostratigraphy data.
Article
Oceanography
Justine Caillet, Nicolas C. C. Jourdain, Pierre Mathiot, Hartmut H. H. Hellmer, Jeremie Mouginot
Summary: Ocean warming around Antarctica may lead to marine ice-sheet instabilities. Weak perturbations of heat, freshwater, or momentum fluxes can switch the Amundsen Sea from warm to cold state, reducing ice-shelf melt rate. These transitions are primarily driven by changes in surface buoyancy fluxes resulting from freshwater flux perturbation or modified net sea-ice production due to either heat flux or sea-ice advection anomalies, affecting ocean stratification and the eastward undercurrent at the shelf break that impact ice-shelf melting.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Environmental Sciences
Kazuya Kusahara
Summary: Recent observations have shown changes in the Antarctic sea ice and ice shelf over the years. Analysis from an ocean-sea ice-ice shelf model reveals a clear anti-correlation between Antarctic sea ice extent and ice shelf basal melting, indicating that the summer sea ice extent can act as a proxy for predicting Antarctic coastal water masses and ice shelf melting.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Michael Wood, Eric Rignot, Ian Fenty, Lu An, Anders Bjork, Michiel van den Broeke, Cilan Cai, Emily Kane, Dimitris Menemenlis, Romain Millan, Mathieu Morlighem, Jeremie Mouginot, Brice Noel, Bernd Scheuchl, Isabella Velicogna, Josh K. Willis, Hong Zhang
Summary: Research shows that the intrusion of warm Atlantic Waters has significantly influenced the retreat of 226 marine-terminating glaciers in Greenland, particularly those located in deep fjords. Excluding ocean-induced undercutting in ice sheet projections may underestimate mass loss by at least a factor of 2.
Article
Multidisciplinary Sciences
Nathan Maier, Florent Gimbert, Fabien Gillet-Chaulet
Summary: Basal motion plays a crucial role in ice speeds in Greenland, which is influenced by meltwater delivery to the ice base. Increasing melt rates enhance bed friction and cause the ice to slow down. However, factors besides melt rates primarily control the impact of melt forcing. The weakening of the southern ablation zone and the strengthening of the northern ablation zone suggest that dynamic changes leading to increased mass loss are likely to occur in northern Greenland as temperatures increase.
Article
Geosciences, Multidisciplinary
Antony J. Payne, Sophie Nowicki, Ayako Abe-Ouchi, Cecile Agosta, Patrick Alexander, Torsten Albrecht, Xylar Asay-Davis, Andy Aschwanden, Alice Barthel, Thomas J. Bracegirdle, Reinhard Calov, Christopher Chambers, Youngmin Choi, Richard Cullather, Joshua Cuzzone, Christophe Dumas, Tamsin L. Edwards, Denis Felikson, Xavier Fettweis, Benjamin K. Galton-Fenzr, Heiko Goelzer, Rupert Gladstone, Nicholas R. Golledge, Jonathan M. Gregory, Ralf Greve, Tore Hattermann, Matthew J. Hoffman, Angelika Humbert, Philippe Huybrechts, Nicolas C. Jourdain, Thomas Kleiner, Peter Kuipers Munneke, Eric Larour, Sebastien Le Clec'h, Victoria Lee, Gunter Leguy, William H. Lipscomb, Christopher M. Little, Daniel P. Lowry, Mathieu Morlighem, Isabel Nias, Frank Pattyn, Tyler Pelle, Stephen F. Price, Aurelien Quiquet, Ronja Reese, Martin Rueckamp, Nicole-Jeanne Schlege, Helene Seroussi, Andrew Shepherd, Erika Simon, Donald Slater, Robin S. Smith, Fiammetta Straneo, Sainan Sun, Lev Tarasov, Luke D. Trusel, Jonas Van Breedam, Roderik van de Wal, Michiel van den Broeke, Ricarda Winkelmann, Chen Zhao, Tong Zhang, Thomas Zwinger
Summary: The latest climate models show that increased melting of the Greenland ice sheet will significantly increase the projected sea level rise, while the contribution from the Antarctic ice sheet falls within the CMIP5 range.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geology
Danni M. Pearce, James M. Lea, Douglas W. F. Mair, Brice R. Rea, J. Edward Schofield, Nicholas A. Kamenos, Kathryn M. Schoenrock, Lukasz Stachnik, Bonnie Lewis, Iestyn Barr, Ruth Mottram
Summary: Our understanding of the relationship between climate and mass flux from marine-terminating tidewater glaciers (TWGs) in the Greenland Ice Sheet has been improved through the study of the largest tidewater glacier in southwest Greenland. The data from the study provide a long-term record of the glacier's advance during the first half of the past millennium and demonstrate the sensitivity of TWGs to climate cooling. These findings validate numerical modeling approaches and have significant implications for prognostic modeling.
Article
Multidisciplinary Sciences
Andrew J. Christ, Paul R. Bierman, Joerg M. Schaefer, Dorthe Dahl-Jensen, Jorgen P. Steffensen, Lee B. Corbett, Dorothy M. Peteet, Elizabeth K. Thomas, Eric J. Steig, Tammy M. Rittenour, Jean-Louis Tison, Pierre-Henri Blard, Nicolas Perdrial, David P. Dethier, Andrea Lini, Alan J. Hidy, Marc W. Caffee, John Southon
Summary: Understanding the history of the Greenland Ice Sheet (GrIS) is crucial for determining its response to climate change and contribution to sea level rise. Through the analysis of subglacial sediment at the base of the Camp Century ice core, researchers have uncovered evidence of at least two episodes of ice-free, vegetated conditions in northwestern Greenland during the Pleistocene, suggesting that the GrIS persisted through much of the Pleistocene but experienced melting and reformation at least once since 1.1 million years ago.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geography, Physical
Jacob Downs, Douglas Brinkerhoff, Mathieu Morlighem
Summary: In this study, we performed Bayesian inference of the parameters of a time-dependent model of ice flow and calving at Helheim Glacier, East Greenland. We found that a time-independent calving parameterization is unable to recover sub-annual variability, while a simple stochastic model relating surface runoff rates and calving threshold can reproduce observations with respect to mean position and temporal variability.
JOURNAL OF GLACIOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Shivani Ehrenfeucht, Mathieu Morlighem, Eric Rignot, Christine F. F. Dow, Jeremie Mouginot
Summary: Using satellite radar interferometry data, researchers observe a seasonal acceleration of Petermann Glacier in northern Greenland, but the physical drivers behind this seasonality have not been explained. By coupling a subglacial hydrology model with an ice sheet model, they find that seasonal changes in subglacial hydrology are sufficient to explain the observed seasonal speed up of the glacier.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Correction
Geosciences, Multidisciplinary
Romain Millan, Jeremie Mouginot, Antoine Rabatel, Mathieu Morlighem
Article
Geosciences, Multidisciplinary
Hilde Oliver, Donald Slater, Dustin Carroll, Michael Wood, Mathieu Morlighem, Mark J. Hopwood
Summary: Subglacial discharge from Greenland's marine-terminating glaciers drives nutrient supply and stimulates phytoplankton growth. The nitrate fluxes are concentrated in a few critical systems, with 14% of glaciers accounting for half of the total flux anomaly. The largest flux occurs at Jakobshavn Isbr AE in Disko Bay, where subglacial discharge is highest. Subglacial discharge and nitrate flux anomaly also contribute to temporal variability in summer satellite chlorophyll a (Chl) near Greenland's coast.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
G. H. Gudmundsson, J. M. Barnes, D. N. Goldberg, M. Morlighem
Summary: The Thwaites Ice Shelf in West Antarctica is rapidly changing and may disintegrate in the near future, resulting in the loss of support for the upstream Thwaites Glacier. Previous studies suggested that this could lead to the rapid demise of the entire glacier due to dynamic instability. In this study, quantitative assessments were conducted to evaluate the level of buttressing provided by the ice shelf and the impact of its collapse on future projections. The results show that the stresses acting along the current grounding line deviate insignificantly after the ice shelf collapse, and the complete disintegration of the ice shelf will not substantially affect future mass loss over the next 50 years.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Editorial Material
Geosciences, Multidisciplinary
Harihar Rajaram, Suzana Camargo, Christopher D. Cappa, Andrew J. Dombard, Kathleen A. Donohue, Sarah Feakins, Lucy Flesch, Alessandra Giannini, Yu Gu, Christian Huber, Valeriy Ivanov, Kristopher Karnauskas, Monika Korte, Gang Lu, Gudrun Magnusdottir, Mathieu Morlighem, German A. Prieto, Bo Qiu, Hui Su, Daoyuan Sun, Kaicun Wang, Caitlin Whalen, Angelicque E. White, Quentin Williams, Andrew Yau
Summary: On behalf of the journal, AGU, and the scientific community, the editors of Geophysical Research Letters express sincere gratitude to the reviewers who contributed to manuscript reviews in 2022. The reviewers' efforts not only improve the quality of the manuscripts but also enhance the scientific rigor of future research. Many reviewers have also played a crucial role in evaluating data accessibility and availability, providing insightful comments to improve data presentation and quality, thus advancing open science as desired by AGU's data policy. The timely reviews provided amidst the demands of the rapid review process at Geophysical Research Letters are particularly appreciated. In 2022, we received 6,687 submissions and 5,247 reviewers contributed 8,720 reviews in total, demonstrating their invaluable contributions in these challenging times.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geography, Physical
Emily Schwans, Byron R. Parizek, Richard B. Alley, Sridhar Anandakrishnan, Mathieu M. Morlighem
Summary: Recent observations show that Thwaites Glacier (TG) is losing mass and its grounding zone is retreating, leading to uncertainties in predicting future sea-level rise contribution. In this study, the Ice Sheet and Sea-level System Model (ISSM) is utilized to simulate TG's response to varying ocean forcing and basal sliding behavior. The results highlight the importance of basin-wide bed character in modulating the glacier's response to sub-shelf melt and influencing the rates and magnitudes of grounding-line retreat and sea-level rise contribution. These findings stress the crucial need to consider bed character in predictive models of West Antarctica.
JOURNAL OF GLACIOLOGY
(2023)
Article
Geography, Physical
Aleah Sommers, Colin Meyer, Mathieu Morlighem, Harihar Rajaram, Kristin Poinar, Winnie Chu, Jessica Mejia
Summary: Water pressure beneath glaciers impacts ice velocity. Subglacial hydrology models help understand basal conditions, but current challenge is reproducing elevated water pressures in winter. We create a minimalist version of the SHAKTI model to explore the winter base state of the subglacial drainage system and find that meltwater supports active winter drainage with elevated water pressure and preferential drainage pathways.
JOURNAL OF GLACIOLOGY
(2023)
Article
Geography, Physical
Nicole Abib, David A. Sutherland, Jason M. Amundson, Dan Duncan, Emily F. Eidam, Rebecca H. Jackson, Christian Kienholz, Mathieu Morlighem, Roman J. Motyka, Jonathan D. Nash, Bridget Ovall, Erin C. Pettit
Summary: Frontal ablation, the combination of submarine melting and iceberg calving, affects the geometry of a glacier's terminus and the distribution of meltwater input. Observing frontal ablation and terminus morphology below the waterline is difficult, limiting our understanding of these ice-ocean processes. Using 3-D multibeam point clouds of the subsurface ice face at LeConte Glacier, Alaska, and concurrent environmental observations, we find that the terminus was predominantly overcut, challenging the assumption that tidewater glacier termini are largely undercut during periods of high submarine melting.
ANNALS OF GLACIOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Sergey Nikiforov, Roman Ananiev, Martin Jakobsson, Evgeny Moroz, Sergey Sokolov, Nikolay Sorokhtin, Nikolay Dmitrevsky, Elena Sukhikh, Igor Chickiryov, Yulia Zarayskaya, Anatoly Razumovskiy, Igor Semiletov
Summary: Based on data acquired during cruises of the RV Akademik Nikolaj Strakhov in 2018-2021, the distribution of submarine glacial landforms in the central part of the Pechora shelf area is revealed. The extent of the ice sheet during the Last Glacial Maximum (LGM) is proposed based on moraines and the distribution of glacial lineations. The mapped glacial landforms indicate the presence of an ice sheet in the area, while the Pechora basin was characterized by a cryogenic subaerial landscape.
Article
Environmental Sciences
Henrieka Detlef, Matt O'Regan, Christian Stranne, Mads Mork Jensen, Marianne Glasius, Thomas M. M. Cronin, Martin Jakobsson, Christof Pearce
Summary: According to climate models, the Lincoln Sea will be the last refuge of perennial Arctic sea-ice in a warming climate, but recent observations show concerns about its long-term stability. A study using marine proxy evidence reveals that perennial sea-ice disappeared in the southern Lincoln Sea during the Early Holocene, suggesting a widespread shift to seasonal sea-ice in the Arctic Ocean. The findings indicate that even if global temperature rise is limited to 2 degrees C compared to pre-industrial levels, the southern Lincoln Sea is likely to transition to seasonal sea-ice due to anthropogenic warming.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
J. Muchowski, L. Arneborg, L. Umlauf, P. Holtermann, E. Eisbrenner, C. Humborg, M. Jakobsson, C. Stranne
Summary: Diapycnal mixing affects the vertical transport rates of salt, heat, and other dissolved substances, which are crucial for the overturning circulation and ecosystem functioning in marine systems. This study investigates the overall impact of non-tidal flow over multiple small-scale bathymetric features on a strongly-stratified density interface in a coastal region. The findings highlight the importance of rough small-scale bathymetric features for the vertical transport of salt in coastal areas.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Alice C. Fremand, Peter Fretwell, Julien A. Bodart, Hamish D. Pritchard, Alan Aitken, Jonathan L. Bamber, Robin Bell, Cesidio Bianchi, Robert G. Bingham, Donald D. Blankenship, Gino Casassa, Ginny Catania, Knut Christianson, Howard Conway, Hugh F. J. Corr, Xiangbin Cui, Detlef Damaske, Volkmar Damm, Reinhard Drews, Graeme Eagles, Olaf Eisen, Hannes Eisermann, Fausto Ferraccioli, Elena Field, Rene Forsberg, Steven Franke, Shuji Fujita, Yonggyu Gim, Vikram Goel, Siva Prasad Gogineni, Jamin Greenbaum, Benjamin Hills, Richard C. A. Hindmarsh, Andrew O. Hoffman, Per Holmlund, Nicholas Holschuh, John W. Holt, Annika N. Horlings, Angelika Humbert, Robert W. Jacobel, Daniela Jansen, Adrian Jenkins, Wilfried Jokat, Tom Jordan, Edward King, Jack Kohler, William Krabill, Mette Kusk Gillespie, Kirsty Langley, Joohan Lee, German Leitchenkov, Carlton Leuschen, Bruce Luyendyk, Joseph MacGregor, Emma MacKie, Kenichi Matsuoka, Mathieu Morlighem, Jeremie Mouginot, Frank O. Nitsche, Yoshifumi Nogi, Ole A. Nost, John Paden, Frank Pattyn, Sergey V. Popov, Eric Rignot, David M. Rippin, Andres Rivera, Jason Roberts, Neil Ross, Anotonia Ruppel, Dustin M. Schroeder, Martin J. Siegert, Andrew M. Smith, Daniel Steinhage, Michael Studinger, Bo Sun, Ignazio Tabacco, Kirsty Tinto, Stefano Urbini, David Vaughan, Brian C. Welch, Douglas S. Wilson, Duncan A. Young, Achille Zirizzotti
Summary: One of the key components of this research is to map Antarctic bed topography and ice thickness parameters, which are crucial for modeling ice flow and predicting future ice loss and sea level rise. The Bedmap3 Action Group, supported by SCAR, aims to produce new gridded maps and make geophysical survey data points available for the international scientific community. They have introduced the SCAR Bedmap Data Portal to provide open access to these datasets. This data release is expected to greatly benefit Antarctic research and extend the life cycle of the data.
EARTH SYSTEM SCIENCE DATA
(2023)
Article
Geography, Physical
Johan Nilsson, Eef van Dongen, Martin Jakobsson, Matt O'Regan, Christian Stranne
Summary: Using a conceptual model, this study investigates the impact of hydraulically controlled exchange flows in silled fjords on the relationship between glacier melt and the features of warm intermediate Atlantic Water (AW) outside the fjords. It is found that changes in the AW interface height, temperature, and glacially modified water production can force an exchange flow into the hydraulic regime. In this regime, heat transport across the sill becomes a limiting factor for basal melt and reduces its sensitivity to changes in AW temperature. The model results are compared with observations from glaciers in northern Greenland.
Article
Multidisciplinary Sciences
Thiago Dias dos Santos, Mathieu Morlighem, Jefferson Cardia Simoes, Philippe Remy Bernard Devloo
Summary: The Lange glacier in Admiralty Bay, King George Island, Peninsula Antarctica has retreated about 1 km since the 1950s. This study investigates the sensitivity of the glacier to changes in flow rate factor, friction coefficient, surface mass balance, and calving front position using a three-dimensional glacier model and satellite and in-situ datasets. The results suggest that the glacier is more sensitive to changes in surface mass balance and flow rate factor, and that the position of the ice front exerts a strong control on the glacier flux.
ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS
(2023)
