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2. Short- and long-term variability of the Antarctic and Greenland ice sheets

Author

Hanna, E., Topál, D., Box, J. E., Buzzard, S., Christie, F. D. W., Hvidberg, C., Morlighem, M., De Santis, L., Silvano, A., Colleoni, F., Sasgen, I., Banwell, A. F., van den Broeke, M. R., DeConto, R., De Rydt, J., Goelzer, H., Gossart, A., Gudmundsson, G. H., Lindbäck, Katrin, Miles, B., Mottram, R., Pattyn, F., Reese, R., Rignot, E., Srivastava, A., Sun, S., Toller, J., Tuckett, P. A., Ultee, L., Hanna, E., Topál, D., Box, J. E., Buzzard, S., Christie, F. D. W., Hvidberg, C., Morlighem, M., De Santis, L., Silvano, A., Colleoni, F., Sasgen, I., Banwell, A. F., van den Broeke, M. R., DeConto, R., De Rydt, J., Goelzer, H., Gossart, A., Gudmundsson, G. H., Lindbäck, Katrin, Miles, B., Mottram, R., Pattyn, F., Reese, R., Rignot, E., Srivastava, A., Sun, S., Toller, J., Tuckett, P. A., and Ultee, L.

Abstract

The variability of the Antarctic and Greenland ice sheets occurs on various timescales and is important for projections of sea level rise; however, there are substantial uncertainties concerning future ice-sheet mass changes. In this Review, we explore the degree to which short-term fluctuations and extreme glaciological events reflect the ice sheets’ long-term evolution and response to ongoing climate change. Short-term (decadal or shorter) variations in atmospheric or oceanic conditions can trigger amplifying feedbacks that increase the sensitivity of ice sheets to climate change. For example, variability in ocean-induced and atmosphere-induced melting can trigger ice thinning, retreat and/or collapse of ice shelves, grounding-line retreat, and ice flow acceleration. The Antarctic Ice Sheet is especially prone to increased melting and ice sheet collapse from warm ocean currents, which could be accentuated with increased climate variability. In Greenland both high and low melt anomalies have been observed since 2012, highlighting the influence of increased interannual climate variability on extreme glaciological events and ice sheet evolution. Failing to adequately account for such variability can result in biased projections of multi-decadal ice mass loss. Therefore, future research should aim to improve climate and ocean observations and models, and develop sophisticated ice sheet models that are directly constrained by observational records and can capture ice dynamical changes across various timescales.

Published
2024
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5. Increased warm water intrusions could cause mass loss in East Antarctica during the next 200 years

Author

Jordan, James Rowan, Miles, B. W. J., Gudmundsson, G. H., Jamieson, S. S. R., Jenkins, A., Stokes, C. R., Jordan, James Rowan, Miles, B. W. J., Gudmundsson, G. H., Jamieson, S. S. R., Jenkins, A., and Stokes, C. R.

Abstract

The East Antarctic Ice Sheet (EAIS) is currently surrounded by relatively cool water, but climatic shifts have the potential to increase basal melting via intrusions of warm modified Circumpolar Deep Water (mCDW) onto the continental shelf. Here we use an ice sheet model to show that under the current ocean regime, with only limited intrusions of mCDW, the EAIS will likely gain mass over the next 200 years due to the increased precipitation from a warming atmosphere outweighing increased ice discharge due to ice-shelf melting. However, if the ocean regime were to become dominated by greater mCDW intrusions, the EAIS would have a negative mass balance, contributing up to 48 mm of SLE over this time period. Our modelling finds George V Land to be particularly at risk to increased ocean induced melting. With warmer oceans, we also find that a mid range RCP4.5 emissions scenario is likely to result in a more negative mass balance than a high RCP8.5 emissions scenario, as the relative difference between increased precipitation due to a warming atmosphere and increased ice discharge due to a warming ocean is more negative in the mid range RCP4.5 emission scenario., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2023

24. Tracking B-31 iceberg with two aircraft deployed sensors

Author

Jones, D. H., Gudmundsson, G. H., Jones, D. H., and Gudmundsson, G. H.

Abstract

Icebergs are a natural hazard to maritime operations in polar regions. Iceberg populations are increasing, as is the demand for access to both Arctic and Antarctic seas. Soon the ability to reliably track icebergs may become a necessity for continued operational safety. The temporal and spatial coverage of remote sensing instruments is limited, and must be supplemented with in situ measurements. In this paper we describe the design of a tracking sensor that can be deployed from a fixed-wing aircraft during iceberg surveys, and detail the results of its first deployment operation on iceberg B-31.

Published
2015

26. Supplementary material to "Experimental design for three interrelated Marine Ice-Sheet and Ocean Model Intercomparison Projects"

Author

Asay-Davis, X. S., primary, Cornford, S. L., additional, Durand, G., additional, Galton-Fenzi, B. K., additional, Gladstone, R. M., additional, Gudmundsson, G. H., additional, Hattermann, T., additional, Holland, D. M., additional, Holland, D., additional, Holland, P. R., additional, Martin, D. F., additional, Mathiot, P., additional, Pattyn, F., additional, and Seroussi, H., additional

Published
2015
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27. Experimental design for three interrelated Marine Ice-Sheet and Ocean Model Intercomparison Projects

Author

Asay-Davis, X. S., primary, Cornford, S. L., additional, Durand, G., additional, Galton-Fenzi, B. K., additional, Gladstone, R. M., additional, Gudmundsson, G. H., additional, Hattermann, T., additional, Holland, D. M., additional, Holland, D., additional, Holland, P. R., additional, Martin, D. F., additional, Mathiot, P., additional, Pattyn, F., additional, and Seroussi, H., additional

Published
2015
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34. Nd isotopes in deep-sea corals in the North Eastern Atlantic

Author

Copard, K., Colin, Christophe, Douville, E., Freiwalde, A., Gudmundsson, G. H., De Mol, B., Frank, N., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Senckenberg Meeresforschung, Iceland Institute, Museum of Natural History, GRC Geociencies Marines, Universitat de Barcelona (UB), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Université de Barcelonne

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2010

35. Retreat of Pine Island Glacier controlled by marine ice-sheet instability

Author

Favier, L., Durand, G., Cornford, S. L., Gudmundsson, G. H., Gagliardini, O., Gillet-Chaulet, F., Zwinger, T., Payne, A. J., Le Brocq, A. M., Favier, L., Durand, G., Cornford, S. L., Gudmundsson, G. H., Gagliardini, O., Gillet-Chaulet, F., Zwinger, T., Payne, A. J., and Le Brocq, A. M.

Abstract

Over the past 40 years Pine Island Glacier in West Antarctica has thinned at an accelerating rate, so that at present it is the largest single contributor to sea-level rise in Antarctica. In recent years, the grounding line, which separates the grounded ice sheet from the floating ice shelf, has retreated by tens of kilometres. At present, the grounding line is crossing a retrograde bedrock slope that lies well below sea level, raising the possibility that the glacier is susceptible to the marine ice-sheet instability mechanism. Here, using three state-of-the-art ice-flow models, we show that Pine Island Glacier's grounding line is probably engaged in an unstable 40km retreat. The associated mass loss increases substantially over the course of our simulations from the average value of 20 Gt yr−1 observed for the 1992–2011 period, up to and above 100 Gt yr−1, equivalent to 3.5–10 mm eustatic sea-level rise over the following 20 years. Mass loss remains elevated from then on, ranging from 60 to 120 Gt yr−1.

Published
2014

36. Halley Research Station, Antarctica: calving risks and monitoring strategies

Author

Anderson, R., Jones, D. H., Gudmundsson, G. H., Anderson, R., Jones, D. H., and Gudmundsson, G. H.

Abstract

The British Antarctic Survey's Halley Research Station is located on the Brunt Ice Shelf, Antarctica, where it is potentially vulnerable to calving events. Existing historical records show that the Brunt Ice Shelf is currently extended further into the Weddell Sea than it was before its last large calving event, so a new calving event may be overdue. We describe three different possible future scenarios for a large-scale calving event on Brunt Ice Shelf, and conclude that the currently most threatening scenario for the Halley Research Station is a calving event on the neighbouring Stancomb–Wills Glacier Tongue, with subsequent detrimental consequences for the stability of the Brunt Ice Shelf. Based on available data, we suggest an increasing likelihood of this scenario occurring after 2020. We furthermore describe ongoing monitoring efforts aimed at giving advanced warning of an imminent calving event.

Published
2014

37. Benchmark experiments for higher-order and full Stokes ice sheet models (ISMIP-HOM)

Author

Pattyn, F., Perichon, L., Aschwanden, A., Breuer, B., De Smedt, B., Gagliardini, O., Gudmundsson, G. H., Hindmarsh, R., Hubbard, A., Johnson, J. V., Kleiner, T., Konovalov, Y., Martin, C., Payne, A. J., Pollard, D., Price, S., Rückamp, M., Saito, F., Soucek, O., Sugiyama, S., Zwinger, T., Laboratoire de Glaciologie, Université Libre de Bruxelles [Bruxelles] (ULB), Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Institute for Geophysics, Westfälische Wilhelms-Universität Münster (WWU), Vakgroep Geografie, Vrije Universiteit [Brussels] (VUB), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Physical Science Division, British Antarctic Survey (BAS), Natural Environment Research Council (NERC)-Natural Environment Research Council (NERC), Centre for Glaciology, Institute of Geography and Earth Sciences, Department of Computer Science [New York], Columbia University [New York], Moscow Engineering Physics Institute, Bristol Glaciology Centre, School of Geographical Sciences, Earth and Environmental Systems Institute, College of Earth and Mineral Sciences, Frontier Research Center for Global Change (FRCGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Department of Geophysics, Charles University [Prague], Institute of Low Temperature Science, Hokkaido University, Scientific Computing Ltd (CSC), Université libre de Bruxelles (ULB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Vrije Universiteit Brussel (VUB), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Pennsylvania State University (Penn State), Penn State System-Penn State System, Charles University [Prague] (CU), Institute of Low Temperature Science [Sapporo], Hokkaido University [Sapporo, Japan], and EGU, Publication

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010103 numerical & computational mathematics, 0101 mathematics, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 01 natural sciences, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences
Abstract

We present the results of the first ice sheet model intercomparison project for higher-order and full Stokes ice sheet models. These models are validated in a series of six benchmark experiments of which one has an analytical solution under simplifying assumptions. Five of the tests are diagnostic and one experiment is prognostic or time dependent, for both 2-D and 3-D geometries. The results show a good convergence of the different models even for high aspect ratios. A clear distinction can be made between higher-order models and those that solve the full system of equations. The latter show a significantly better agreement with each other as well as with analytical solutions, which demonstrates that they are hardly influenced by the used numerics.

Published
2008

38. Analytical analysis of small-amplitude perturbations in the shallow ice stream approximation

Author

Gudmundsson, G. H. and EGU, Publication

Subjects
[SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, Physics::Geophysics
Abstract

New analytical solutions describing the effects of small-amplitude perturbations in boundary data on flow in the shallow ice stream approximation are presented. These solutions are valid for a non-linear Weertman-type sliding law and for Newtonian ice rheology. Comparison is made with corresponding solutions of the shallow ice sheet approximation, and with solutions of the full Stokes equations. The shallow ice stream approximation is commonly used to describe large-scale ice stream flow over a weak bed, while the shallow ice sheet approximation forms the basis of most current large-scale ice sheet models. It is found that the shallow ice stream approximation overestimates the effects of bedrock perturbations on surface topography for wavelengths less than about 5 to 10 ice thicknesses, the exact number depending on values of surface slope and slip ratio. For high slip ratios, the shallow ice stream approximation gives a very simple description of the relationship between bed and surface topography, with the corresponding transfer amplitudes being close to unity for any given wavelength. The shallow ice stream estimates for the timescales that govern the transient response of ice streams to external perturbations are considerably more accurate than those based on the shallow ice sheet approximation. In contrast to the shallow ice sheet approximation, the shallow ice stream approximation correctly reproduces the short-wavelength limit of the kinematic phase speed. In accordance with the full system solutions, the shallow ice sheet approximation predicts surface fields to react weakly to spatial variations in basal slipperiness with wavelengths less than about 10 to 20 ice thicknesses.

Published
2008

39. On estimating length fluctuations of glaciers caused by changes in climatic forcing

Author

Leysinger Vieli, G. J.-M. C. and Gudmundsson, G. H.

Abstract

The reaction of alpine glaciers to shifts in the equilibrium line altitude (ELA) is calculated by using a two-dimensional numerical model to solve the full equations for the velocity and stress fields (full-system model) in the absence of basal motion. Rates of advance and retreat of the snout of typically sized alpine glaciers are found to be insensitive to the details of the flow at the snout, even when the glaciers are far from steady state. A comparison of results obtained with a full-system model and a shallow ice approximation (SIA) model yields no significant differences in advance or retreat rates. This assumption has been implicitly made in numerous previous climatic studies and is here shown to be well justified. Using a realistic mass balance altitude feedback, only slight model-dependent changes in steady state lengths are found. The relative importance of mass balance and glacier dynamics for the transient response of alpine glaciers to changes in the ELA is given a precise meaning by determining the model-dependent additional shifts in ELA needed for the SIA and the full-system models to produce identical changes in length. For alpine glaciers, these additional shifts in ELA are on the order of 10 m, which is within the error range of ELA estimates. It follows that at least in the absence of significant basal motion, there is no need to include the effects of horizontal stresses when calculating the reaction of alpine glaciers to climatic changes. Attention should focus on accurate determination of the mass balance distribution and model tuning to give realistic ice thickness distributions.

Published
2004

46. Longitudinal surface structures (flowstripes) on Antarctic glaciers

Author

Glasser, N. F., Gudmundsson, G. H., Glasser, N. F., and Gudmundsson, G. H.

Abstract

Longitudinal surface structures (“flowstripes”) are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems; the Lambert Glacier/Amery Ice Shelf area, the Taylor and Ferrar Glaciers in the Ross Sea sector, Crane and Jorum Glaciers (ice-shelf tributary glaciers) on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1) as relatively wide flow stripes within glacier flow units and (2) as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

Published
2012

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