Massive subsurface ice formed by refreezing of ice-shelf melt ponds

• Published in: Nature Communications
• Main Authors: Hubbard, Bryn, Luckman, Adrian, Ashmore, David W, Bevan, Suzanne, Kulessa, Bernd, Munneke, Peter Kuipers, Philippe, Morgane, Jansen, Daniela, Booth, Adam, Sevestre, Heidi, Tison, Jean-Louis, O'Leary, Martin, Rutt, Ian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2016
• Subjects: Antarctic; Antarc*; Antarctica; Ice Shelf; Ice Shelves
• Online Access: https://livrepository.liverpool.ac.uk/3006703/; https://doi.org/10.1038/ncomms11897; https://livrepository.liverpool.ac.uk/3006703/1/hubbard2016_natcomm.pdf

Surface melt ponds form intermittently on several Antarctic ice shelves. Although implicated in ice-shelf break up, the consequences of such ponding for ice formation and ice-shelf structure have not been evaluated. Here we report the discovery of a massive subsurface ice layer, at least 16 km across, several kilometres long and tens of metres deep, located in an area of intense melting and intermittent ponding on Larsen C Ice Shelf, Antarctica. We combine borehole optical televiewer logging and radar measurements with remote sensing and firn modelling to investigate the layer, found to be ∼10 °C warmer and ∼170 kg m(-3) denser than anticipated in the absence of ponding and hitherto used in models of ice-shelf fracture and flow. Surface ponding and ice layers such as the one we report are likely to form on a wider range of Antarctic ice shelves in response to climatic warming in forthcoming decades.