Articles | Volume 15, issue 8
27 Aug 2021
Research article | 27 Aug 2021
Rapid and accurate polarimetric radar measurements of ice crystal fabric orientation at the Western Antarctic Ice Sheet (WAIS) Divide ice core site
Tun Jan Young et al.
No articles found.
Hilary A. Dugan, Peter T. Doran, Denys Grombacher, Esben Auken, Thue Bording, Nikolaj Foged, Neil Foley, Jill Mikucki, Ross A. Virginia, and Slawek Tulaczyk
The Cryosphere Discuss.,
Preprint under review for TCShort summary
In the McMurdo Dry Valleys of Antarctica, a deep groundwater system has been hypothesized to connect Don Juan Pond and Lake Vanda, both surface waterbodies that contain very high concentrations of salt. This is unusual, since permafrost in polar landscapes is thought to prevent subsurface hydrologic connectivity. We show results from an airborne geophysical survey that reveals widespread unfrozen brine in Wright Valley, and points to the potential for deep valley-wide brine conduits.
M. Reza Ershadi, Reinhard Drews, Carlos Martín, Olaf Eisen, Catherine Ritz, Hugh Corr, Julia Christmann, Ole Zeising, Angelika Humbert, and Robert Mulvaney
The Cryosphere, 16, 1719–1739,Short summary
Radio waves transmitted through ice split up and inform us about the ice sheet interior and orientation of single ice crystals. This can be used to infer how ice flows and improve projections on how it will evolve in the future. Here we used an inverse approach and developed a new algorithm to infer ice properties from observed radar data. We applied this technique to the radar data obtained at two EPICA drilling sites, where ice cores were used to validate our results.
Julie Z. Miller, Riley Culberg, David G. Long, Christopher A. Shuman, Dustin M. Schroeder, and Mary J. Brodzik
The Cryosphere, 16, 103–125,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.
Alexander O. Hager, Matthew J. Hoffman, Stephen F. Price, and Dustin M. Schroeder
The Cryosphere Discuss.,
Revised manuscript accepted for TCShort summary
The presence of water beneath glaciers is a control on glacier speed and ocean-caused melting, yet it has been unclear whether sizeable volumes of water can exist beneath Antarctic glaciers, or how this water may flow along the glacier bed. We use computer simulations, supported by observations, to show that enough water exists at the base of Thwaites Glacier, Antarctica, to form "rivers" beneath the glacier. These rivers likely moderate glacier speed and may influence its rate of retreat.
Marie G. P. Cavitte, Duncan A. Young, Robert Mulvaney, Catherine Ritz, Jamin S. Greenbaum, Gregory Ng, Scott D. Kempf, Enrica Quartini, Gail R. Muldoon, John Paden, Massimo Frezzotti, Jason L. Roberts, Carly R. Tozer, Dustin M. Schroeder, and Donald D. Blankenship
Earth Syst. Sci. Data, 13, 4759–4777,Short summary
We present a data set consisting of ice-penetrating-radar internal stratigraphy: 26 internal reflecting horizons that cover the greater Dome C area, East Antarctica, the most extensive IRH data set to date in the region. This data set uses radar surveys collected over the span of 10 years, starting with an airborne international collaboration in 2008 to explore the region, up to the detailed ground-based surveys in support of the European Beyond EPICA – Oldest Ice (BE-OI) project.
Sarah U. Neuhaus, Slawek M. Tulaczyk, Nathan D. Stansell, Jason J. Coenen, Reed P. Scherer, Jill A. Mikucki, and Ross D. Powell
The Cryosphere, 15, 4655–4673,Short summary
We estimate the timing of post-LGM grounding line retreat and readvance in the Ross Sea sector of Antarctica. Our analyses indicate that the grounding line retreated over our field sites within the past 5000 years (coinciding with a warming climate) and readvanced roughly 1000 years ago (coinciding with a cooling climate). Based on these results, we propose that the Siple Coast grounding line motions in the middle to late Holocene were driven by relatively modest changes in regional climate.
Krista F. Myers, Peter T. Doran, Slawek M. Tulaczyk, Neil T. Foley, Thue S. Bording, Esben Auken, Hilary A. Dugan, Jill A. Mikucki, Nikolaj Foged, Denys Grombacher, and Ross A. Virginia
The Cryosphere, 15, 3577–3593,Short summary
Lake Fryxell, Antarctica, has undergone hundreds of meters of change in recent geologic history. However, there is disagreement on when lake levels were higher and by how much. This study uses resistivity data to map the subsurface conditions (frozen versus unfrozen ground) to map ancient shorelines. Our models indicate that Lake Fryxell was up to 60 m higher just 1500 to 4000 years ago. This amount of lake level change shows how sensitive these systems are to small changes in temperature.
David A. Lilien, Daniel Steinhage, Drew Taylor, Frédéric Parrenin, Catherine Ritz, Robert Mulvaney, Carlos Martín, Jie-Bang Yan, Charles O'Neill, Massimo Frezzotti, Heinrich Miller, Prasad Gogineni, Dorthe Dahl-Jensen, and Olaf Eisen
The Cryosphere, 15, 1881–1888,Short summary
We collected radar data between EDC, an ice core spanning ~800 000 years, and BELDC, the site chosen for a new
oldest icecore at nearby Little Dome C. These data allow us to identify 50 % older internal horizons than previously traced in the area. We fit a model to the ages of those horizons at BELDC to determine the age of deep ice there. We find that there is likely to be 1.5 Myr old ice ~265 m above the bed, with sufficient resolution to preserve desired climatic information.
Slawek M. Tulaczyk and Neil T. Foley
The Cryosphere, 14, 4495–4506,Short summary
Much of what we know about materials hidden beneath glaciers and ice sheets on Earth has been interpreted using radar reflection from the ice base. A common assumption is that electrical conductivity of the sub-ice materials does not influence the reflection strength and that the latter is controlled only by permittivity, which depends on the fraction of water in these materials. Here we argue that sub-ice electrical conductivity should be generally considered when interpreting radar records.
Iain Wheel, Poul Christoffersen, and Sebastian H. Mernild
The Cryosphere Discuss.,
Manuscript not accepted for further reviewShort summary
Down-fjord winds, known as katabatic winds, are shown to increase water temperatures close to Helheim Glacier through circulation changes. More importantly, strong winds are shown to break up the sea-ice and iceberg matrix in front of the glacier which through a loss of support to the glacier leads to retreat of up to 1.5 km. Therefore katabatic winds are hypothesised to play an important role in the retreat of Helheim Glacier and to be important in the retreat of other Greenland glaciers.
Samuel J. Cook, Poul Christoffersen, Joe Todd, Donald Slater, and Nolwenn Chauché
The Cryosphere, 14, 905–924,Short summary
This paper models how water flows beneath a large Greenlandic glacier and how the structure of the drainage system it flows in changes over time. We also look at how this affects melting driven by freshwater plumes at the glacier front, as well as the implications for glacier flow and sea-level rise. We find an active drainage system and plumes exist year round, contradicting previous assumptions and suggesting more melting may not slow the glacier down, unlike at other sites in Greenland.
Michael A. Cooper, Thomas M. Jordan, Dustin M. Schroeder, Martin J. Siegert, Christopher N. Williams, and Jonathan L. Bamber
The Cryosphere, 13, 3093–3115,
Sarah U. Neuhaus, Slawek M. Tulaczyk, and Carolyn Branecky Begeman
The Cryosphere, 13, 1785–1799,Short summary
Relatively few studies have been carried out on icebergs inside fjords, despite the fact that the majority of recent sea level rise has resulted from glaciers terminating in fjords. We examine the size and spatial distribution of icebergs in Columbia Fjord, Alaska, over a period of 8 months to determine their influence on fjord dynamics.
Joe Todd, Poul Christoffersen, Thomas Zwinger, Peter Råback, and Douglas I. Benn
The Cryosphere, 13, 1681–1694,Short summary
The Greenland Ice Sheet loses 30 %–60 % of its ice due to iceberg calving. Calving processes and their links to climate are not well understood or incorporated into numerical models of glaciers. Here we use a new 3-D calving model to investigate calving at Store Glacier, West Greenland, and test its sensitivity to increased submarine melting and reduced support from ice mélange (sea ice and icebergs). We find Store remains fairly stable despite these changes, but less so in the southern side.
Thomas R. Chudley, Poul Christoffersen, Samuel H. Doyle, Antonio Abellan, and Neal Snooke
The Cryosphere, 13, 955–968,Short summary
Unmanned Aerial Vehicles (UAVs) are increasingly common tools in the geosciences, but their use requires good ground control in order to make accurate georeferenced models. This is difficult in applications such as glaciology, where access to study sites can be hazardous. We show that a new technique utilising on-board GPS post-processing can match and even improve on ground-control-based methods, and, as a result, can produce accurate glacier velocity fields even on an inland ice sheet.
Brent C. Christner, Heather F. Lavender, Christina L. Davis, Erin E. Oliver, Sarah U. Neuhaus, Krista F. Myers, Birgit Hagedorn, Slawek M. Tulaczyk, Peter T. Doran, and William C. Stone
The Cryosphere, 12, 3653–3669,Short summary
Solar radiation that penetrates into the glacier heats the ice to produce nutrient-containing meltwater and provides light that fuels an ecosystem within the ice. Our analysis documents a near-surface photic zone in a glacier that functions as a liquid water oasis in the ice over half the annual cycle. Since microbial growth on glacier surfaces reduces the amount of solar radiation reflected, microbial processes at depths below the surface may also darken ice and accelerate meltwater production.
Thomas M. Jordan, Christopher N. Williams, Dustin M. Schroeder, Yasmina M. Martos, Michael A. Cooper, Martin J. Siegert, John D. Paden, Philippe Huybrechts, and Jonathan L. Bamber
The Cryosphere, 12, 2831–2854,Short summary
Here, via analysis of radio-echo sounding data, we place a new observational constraint upon the basal water distribution beneath the Greenland Ice Sheet. In addition to the outlet glaciers, we demonstrate widespread water storage in the northern and eastern ice-sheet interior, a notable feature being a "corridor" of basal water extending from NorthGRIP to Petermann Glacier. The basal water distribution and its relationship with basal temperature provides a new constraint for numerical models.
Thomas M. Jordan, Michael A. Cooper, Dustin M. Schroeder, Christopher N. Williams, John D. Paden, Martin J. Siegert, and Jonathan L. Bamber
The Cryosphere, 11, 1247–1264,Short summary
Using radio-echo sounding data from northern Greenland, we demonstrate that subglacial roughness exhibits self-affine (fractal) scaling behaviour. This enables us to assess topographic control upon the bed-echo waveform, and explain the spatial distribution of the degree of scattering (specular and diffuse reflections). Via comparison with a prediction for the basal thermal state (thawed and frozen regions of the bed) we discuss the consequences of our study for basal water discrimination.
Daniel Farinotti, Douglas J. Brinkerhoff, Garry K. C. Clarke, Johannes J. Fürst, Holger Frey, Prateek Gantayat, Fabien Gillet-Chaulet, Claire Girard, Matthias Huss, Paul W. Leclercq, Andreas Linsbauer, Horst Machguth, Carlos Martin, Fabien Maussion, Mathieu Morlighem, Cyrille Mosbeux, Ankur Pandit, Andrea Portmann, Antoine Rabatel, RAAJ Ramsankaran, Thomas J. Reerink, Olivier Sanchez, Peter A. Stentoft, Sangita Singh Kumari, Ward J. J. van Pelt, Brian Anderson, Toby Benham, Daniel Binder, Julian A. Dowdeswell, Andrea Fischer, Kay Helfricht, Stanislav Kutuzov, Ivan Lavrentiev, Robert McNabb, G. Hilmar Gudmundsson, Huilin Li, and Liss M. Andreassen
The Cryosphere, 11, 949–970,Short summary
ITMIX – the Ice Thickness Models Intercomparison eXperiment – was the first coordinated performance assessment for models inferring glacier ice thickness from surface characteristics. Considering 17 different models and 21 different test cases, we show that although solutions of individual models can differ considerably, an ensemble average can yield uncertainties in the order of 10 ± 24 % the mean ice thickness. Ways forward for improving such estimates are sketched.
A. Damsgaard, D. L. Egholm, J. A. Piotrowski, S. Tulaczyk, N. K. Larsen, and C. F. Brædstrup
The Cryosphere, 9, 2183–2200,Short summary
This paper details a new algorithm for performing computational experiments of subglacial granular deformation. The numerical approach allows detailed studies of internal sediment and pore-water dynamics under shear. Feedbacks between sediment grains and pore water can cause rate-dependent strengthening, which additionally contributes to the plastic shear strength of the granular material. Hardening can stabilise patches of the subglacial beds with implications for landform development.
C. Martín, R. Mulvaney, G. H. Gudmundsson, and H. Corr
Clim. Past, 11, 547–557,
J. C. Ryan, A. L. Hubbard, J. E. Box, J. Todd, P. Christoffersen, J. R. Carr, T. O. Holt, and N. Snooke
The Cryosphere, 9, 1–11,Short summary
An unmanned aerial vehicle (UAV) equipped with a commercial digital camera enabled us to obtain high-resolution digital images of the calving front of Store glacier, Greenland. The three sorties flown enabled key glaciological parameters to be quantified in sufficient detail to reveal that the terminus of Store glacier is a complex system with large variations in crevasse patterns surface velocities, calving processes, surface elevations and front positions at a daily and seasonal timescale.
J. Todd and P. Christoffersen
The Cryosphere, 8, 2353–2365,Short summary
Many iceberg-calving glaciers in Greenland have recently been observed to accelerate and retreat, prompting fears about their future stability in the face of climate change. We present results from a flow modelling study of Store Glacier, West Greenland, which suggest that glacier geometry may play an important role in determining calving glacier stability. Store Glacier flows into a narrow, shallow fjord and our model suggests this may make it insensitive to future ocean warming.
B. Sun, J. C. Moore, T. Zwinger, L. Zhao, D. Steinhage, X. Tang, D. Zhang, X. Cui, and C. Martín
The Cryosphere, 8, 1121–1128,
T. Zwinger, M. Schäfer, C. Martín, and J. C. Moore
The Cryosphere, 8, 607–621,
O. Gagliardini, T. Zwinger, F. Gillet-Chaulet, G. Durand, L. Favier, B. de Fleurian, R. Greve, M. Malinen, C. Martín, P. Råback, J. Ruokolainen, M. Sacchettini, M. Schäfer, H. Seddik, and J. Thies
Geosci. Model Dev., 6, 1299–1318,
J. De Rydt, G. H. Gudmundsson, H. F. J. Corr, and P. Christoffersen
The Cryosphere, 7, 407–417,
M. O'Leary and P. Christoffersen
The Cryosphere, 7, 119–128,
Related subject area
Discipline: Ice sheets | Subject: Field StudiesDownhole distributed acoustic seismic profiling at Skytrain Ice Rise, West AntarcticaGlacier algae accelerate melt rates on the south-western Greenland Ice SheetPore morphology of polar firn around closure revealed by X-ray tomography
Alex M. Brisbourne, Michael Kendall, Sofia-Katerina Kufner, Thomas S. Hudson, and Andrew M. Smith
The Cryosphere, 15, 3443–3458,Short summary
How ice sheets flowed in the past is written into the structure and texture of the ice sheet itself. Measuring this structure and properties of the ice can help us understand the recent behaviour of the ice sheets. We use a relatively new technique, not previously attempted in Antarctica, to measure the seismic vibrations of a fibre optic cable down a borehole. We demonstrate the potential of this technique to unravel past ice flow and see hints of these complex signals from the ice flow itself.
Joseph M. Cook, Andrew J. Tedstone, Christopher Williamson, Jenine McCutcheon, Andrew J. Hodson, Archana Dayal, McKenzie Skiles, Stefan Hofer, Robert Bryant, Owen McAree, Andrew McGonigle, Jonathan Ryan, Alexandre M. Anesio, Tristram D. L. Irvine-Fynn, Alun Hubbard, Edward Hanna, Mark Flanner, Sathish Mayanna, Liane G. Benning, Dirk van As, Marian Yallop, James B. McQuaid, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 309–330,Short summary
Melting of the Greenland Ice Sheet (GrIS) is a major source of uncertainty for sea level rise projections. Ice-darkening due to the growth of algae has been recognized as a potential accelerator of melting. This paper measures and models the algae-driven ice melting and maps the algae over the ice sheet for the first time. We estimate that as much as 13 % total runoff from the south-western GrIS can be attributed to these algae, showing that they must be included in future mass balance models.
Alexis Burr, Clément Ballot, Pierre Lhuissier, Patricia Martinerie, Christophe L. Martin, and Armelle Philip
The Cryosphere, 12, 2481–2500,Short summary
Three-dimensional imaging of the pore network of polar firn from Antarctica was realized in order to relate the morphological evolution of pores with their progressive closure with depth. Evaluating the closed porosity was found to be very dependent on the size of samples and image reconstructions. A connectivity index, which is a parameter less dependent on such issues, was proposed and proved to accurately predict the close-off depths and densities of two polar sites.
Brisbourne, A. M., Martín, C., Smith, A. M., Baird, A. F., Kendall, J. M., and Kingslake, J.: Constraining Recent Ice Flow History at Korff Ice Rise, West Antarctica, Using Radar and Seismic Measurements of Ice Fabric, J. Geophys. Res.-Earth, 124, 175–194, https://doi.org/10.1029/2018JF004776, 2019. a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w
Cuffey, K. and Paterson, W. S.: The Physics of Glaciers, 4th edn., Academic Press, Amsterdam, 2010. a
Dall, J.: Estimation of crystal orientation fabric from airborne polarimetric ice sounding radar data, in: 40th International Geoscience and Remote Sensing Symposium (IGARSS 2020), IEEE, Waikoloa, HI, 26 September–2 October 2020, 2975–2978, 2021. a
Davis, P. E., Jenkins, A., Nicholls, K. W., Brennan, P. V., Abrahamsen, E. P., Heywood, K. J., Dutrieux, P., Cho, K. H., and Kim, T. W.: Variability in Basal Melting Beneath Pine Island Ice Shelf on Weekly to Monthly Timescales, J. Geophys. Res.-Oceans, 123, 8655–8669, https://doi.org/10.1029/2018JC014464, 2018. a
Durand, G., Gillet-Chaulet, F., Svensson, A., Gagliardini, O., Kipfstuhl, S., Meyssonnier, J., Parrenin, F., Duval, P., and Dahl-Jensen, D.: Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core, Clim. Past, 3, 155–167, https://doi.org/10.5194/cp-3-155-2007, 2007. a
Ershadi, M. R., Drews, R., Martín, C., Eisen, O., Ritz, C., Corr, H., Christmann, J., Zeising, O., Humbert, A., and Mulvaney, R.: Polarimetric radar reveals the spatial distribution of ice fabric at domes in East Antarctica, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2020-370, in review, 2021. a, b, c, d, e, f, g, h
Fitzpatrick, J. J., Voigt, D. E., Fegyveresi, J. M., Stevens, N. T., Spencer, M. K., Cole-Dai, J., Alley, R. B., Jardine, G. E., Cravens, E. D., Wilen, L. A., Fudge, T. J., and McConnell, J. R.: Physical properties of the WAIS divide ice core, J. Glaciol., 60, 1140–1154, https://doi.org/10.3189/2014JoG14J100, 2014. a, b, c, d, e, f, g, h, i, j
Fudge, T. J., Steig, E. J., Markle, B. R., Schoenemann, S. W., Ding, Q., Taylor, K. C., McConnell, J. R., Brook, E. J., Sowers, T., White, J. W., Alley, R. B., Cheng, H., Clow, G. D., Cole-Dai, J., Conway, H., Cuffey, K. M., Edwards, J. S., Lawrence Edwards, R., Edwards, R., Fegyveresi, J. M., Ferris, D., Fitzpatrick, J. J., Johnson, J., Hargreaves, G., Lee, J. E., Maselli, O. J., Mason, W., McGwire, K. C., Mitchell, L. E., Mortensen, N., Neff, P., Orsi, A. J., Popp, T. J., Schauer, A. J., Severinghaus, J. P., Sigl, M., Spencer, M. K., Vaughn, B. H., Voigt, D. E., Waddington, E. D., Wang, X., and Wong, G. J.: Onset of deglacial warming in West Antarctica driven by local orbital forcing, Nature, 500, 440–444, https://doi.org/10.1038/nature12376, 2013. a
Fujita, S., Matsuoka, T., Ishida, T., Matsuoka, K., and Mae, S.: A summary of the complex dielectric permittivity of ice in the megahertz range and its applications for radar sounding of polar ice sheets, in: Physics of Ice Core Records, edited by: Hondoh, T., Hokkaido University Press, Sapporo, Japan, 185–212, 2000. a
Gillet-Chaulet, F., Hindmarsh, R. C. A., Corr, H. F. J., King, E. C., and Jenkins, A.: In-situ quantification of ice rheology and direct measurement of the Raymond Effect at Summit, Greenland using a phase-sensitive radar, Geophys. Res. Lett., 38, L24503, https://doi.org/10.1029/2011GL049843, 2011. a
IPCC: Climate Change 2013: The Physical Science Basis, 5th edn., Cambridge University Press, Cambridge, UK and New York, NY, USA, 2013. a
Jordan, T. M., Schroeder, D. M., Castelletti, D., Li, J., and Dall, J.: A Polarimetric Coherence Method to Determine Ice Crystal Orientation Fabric From Radar Sounding: Application to the NEEM Ice Core Region, IEEE T. Geosci. Remote, 57, 8641–8657, https://doi.org/10.1109/tgrs.2019.2921980, 2019. a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u
Kendrick, A. K., Schroeder, D. M., Chu, W., Young, T. J., Christoffersen, P., Todd, J., Doyle, S. H., Box, J. E., Hubbard, A., Hubbard, B., Brennan, P. V., Nicholls, K. W., and Lok, L. B.: Surface Meltwater Impounded by Seasonal Englacial Storage in West Greenland, Geophys. Res. Lett., 45, 10474–10481, https://doi.org/10.1029/2018GL079787, 2018. a
Kingslake, J., Hindmarsh, R. C. A., Aalgeirsdõttir, G., Conway, H., Corr, H. F. J., Gillet-Chaulet, F., Martín, C., King, E. C., Mulvaney, R., and Pritchard, H. D.: Full-depth englacial vertical ice sheet velocities measured using phase-sensitive radar, J. Geophys. Res.-Earth, 119, 2604–2618, https://doi.org/10.1002/2014JF003275, 2014. a
Kluskiewicz, D., Waddington, E. D., Anandakrishnan, S., Voigt, D. E., Matsuoka, K., and McCarthy, M. P.: Sonic methods for measuring crystal orientation fabric in ice, and results from the West Antarctic ice sheet (WAIS) Divide, J. Glaciol., 63, 603–617, https://doi.org/10.1017/jog.2017.20, 2017. a, b, c
Koutnik, M. R., Fudge, T. J., Conway, H., Waddington, E. D., Neumann, T. A., Cuffey, K. M., Buizert, C., and Taylor, K. C.: Holocene accumulation and ice flow near the West Antarctic Ice Sheet Divide ice core site, J. Geophys. Res.-Earth, 121, 907–924, https://doi.org/10.1002/2015JF003668, 2016. a, b, c
Li, J., Vélez González, J. A., Leuschen, C., Harish, A., Gogineni, P., Montagnat, M., Weikusat, I., Rodriguez-Morales, F., and Paden, J.: Multi-channel and multi-polarization radar measurements around the NEEM site, The Cryosphere, 12, 2689–2705, https://doi.org/10.5194/tc-12-2689-2018, 2018. a, b, c, d
Lindbäck, K., Moholdt, G., Nicholls, K. W., Hattermann, T., Pratap, B., Thamban, M., and Matsuoka, K.: Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars, The Cryosphere, 13, 2579–2595, https://doi.org/10.5194/tc-13-2579-2019, 2019. a
Matsuoka, K., Furukawa, T., Fujita, S., Maeno, H., Uratsuka, S., Naruse, R., and Watanabe, O.: Crystal orientation fabrics within the Antarctic ice sheet revealed by a multipolarization plane and dual-frequency radar survey, J. Geophys. Res., 108, 10, https://doi.org/10.1029/2003JB002425, 2003. a, b, c, d
Matsuoka, K., Power, D., Fujita, S., and Raymond, C. F.: Rapid development of anisotropic ice-crystal-alignment fabrics inferred from englacial radar polarimetry, central West Antarctica, J. Geophys. Res.-Earth, 117, 1–16, https://doi.org/10.1029/2012JF002440, 2012. a, b, c, d, e, f, g, h, i, j, k, l, m
Montagnat, M., Azuma, N., Dahl-Jensen, D., Eichler, J., Fujita, S., Gillet-Chaulet, F., Kipfstuhl, S., Samyn, D., Svensson, A., and Weikusat, I.: Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores, The Cryosphere, 8, 1129–1138, https://doi.org/10.5194/tc-8-1129-2014, 2014. a
Morlighem, M., Rignot, E., Binder, T., Blankenship, D., Drews, R., Eagles, G., Eisen, O., Ferraccioli, F., Forsberg, R., Fretwell, P., Goel, V., Greenbaum, J. S., Gudmundsson, H., Guo, J., Helm, V., Hofstede, C., Howat, I., Humbert, A., Jokat, W., Karlsson, N. B., Lee, W. S., Matsuoka, K., Millan, R., Mouginot, J., Paden, J., Pattyn, F., Roberts, J., Rosier, S., Ruppel, A., Seroussi, H., Smith, E. C., Steinhage, D., Sun, B., van den Broeke, M. R., van Ommen, T. D., van Wessem, M., and Young, D. A.: Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet, Nat. Geosci., 13, 132–137, https://doi.org/10.1038/s41561-019-0510-8, 2020. a
Nakata, N., Bai, T., Zhang, Z., Karplus, M. S., Kaip, G. M., Walter, J. I., Booth, A. D., Christoffersen, P., and Tulaczyk, S. M.: Seismic anisotropy at the Western Antarctic Ice Sheet (WAIS) divide using explosive seismic sources, J. Glac., in preparation, 2021.
Nicholls, K. W., Corr, H. F. J., Stewart, C. L., Lok, L. B., Brennan, P. V., and Vaughan, D. G.: Instruments and methods: A ground-based radar for measuring vertical strain rates and time-varying basal melt rates in ice sheets and shelves, J. Glaciol., 61, 1079–1087, https://doi.org/10.3189/2015JoG15J073, 2015. a, b, c, d
Sigl, M., Fudge, T. J., Winstrup, M., Cole-Dai, J., Ferris, D., McConnell, J. R., Taylor, K. C., Welten, K. C., Woodruff, T. E., Adolphi, F., Bisiaux, M., Brook, E. J., Buizert, C., Caffee, M. W., Dunbar, N. W., Edwards, R., Geng, L., Iverson, N., Koffman, B., Layman, L., Maselli, O. J., McGwire, K., Muscheler, R., Nishiizumi, K., Pasteris, D. R., Rhodes, R. H., and Sowers, T. A.: The WAIS Divide deep ice core WD2014 chronology – Part 2: Annual-layer counting (0–31 ka BP), Clim. Past, 12, 769–786, https://doi.org/10.5194/cp-12-769-2016, 2016. a
Wang, B., Sun, B., Martin, C., Ferraccioli, F., Steinhage, D., Cui, X., and Siegert, M. J.: Summit of the East Antarctic ice sheet underlain by thick ice-crystal fabric layers linked to glacial-interglacial environmental change, Geol. Soc. Spec. Publ., 461, 131–143, https://doi.org/10.1144/SP461.1, 2018. a
Young, T. J. and Dawson, E. J.: Quad-polarimetric ApRES measurements along a 6 km-long transect at the WAIS Divide, December 2019 (Version 1.0) [Data set], NERC EDS UK Polar Data Centre, https://doi.org/10.5285/BA1CAF7A-D4E0-4671-972A-E567A25CCD2C, 2021. a
Young, T. J., Schroeder, D. M., Christoffersen, P., Lok, L. B., Nicholls, K. W., Brennan, P. V., Doyle, S. H., Hubbard, B., and Hubbard, A.: Resolving the internal and basal geometry of ice masses using imaging phase-sensitive radar, J. Glaciol., 64, 649–660, https://doi.org/10.1017/jog.2018.54, 2018. a, b, c
Young, T. J., Christoffersen, P., Doyle, S. H., Nicholls, K. W., Stewart, C. L., Hubbard, B., Hubbard, A., Lok, L. B., Brennan, P. V., Benn, D. I., Luckman, A., and Bougamont, M.: Physical Conditions of Fast Glacier Flow: 3. Seasonally-Evolving Ice Deformation on Store Glacier, West Greenland, J. Geophys. Res.-Earth, 124, 245–267, https://doi.org/10.1029/2018JF004821, 2019. a
Young, T. J., Schroeder, D. M., Jordan, T. M., Christoffersen, P., Tulaczyk, S. M., Culberg, R., and Bienert, N. L.: Inferring ice fabric from birefringence loss in airborne radargrams: Application to the eastern shear margin of Thwaites Glacier, West Antarctica, J. Geophys. Res.-Earth, 126, 1–26, https://doi.org/10.1029/2020jf006023, 2021. a
If the molecules that make up ice are oriented in specific ways, the ice becomes softer and enhances flow. We use radar to measure the orientation of ice molecules in the top 1400 m of the Western Antarctic Ice Sheet Divide. Our results match those from an ice core extracted 10 years ago and conclude that the ice flow has not changed direction for the last 6700 years. Our methods are straightforward and accurate and can be applied in places across ice sheets unsuitable for ice coring.
If the molecules that make up ice are oriented in specific ways, the ice becomes softer and...