Letter | Published:

Increased flow speed on a large East Antarctic outlet glacier caused by subglacial floods

Nature Geoscience volume 1, pages 827831 (2008) | Download Citation

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Abstract

Changes in the velocity of large outlet glaciers and ice streams in Greenland and Antarctica are important for ice-sheet mass balance and hence sea level1. Mass loss in large parts of both ice sheets is being driven by the recent accelerations of outlet glaciers2,3,4,5 in response to unknown or poorly constrained climatic or internal perturbations in their boundary conditions. Surprisingly active networks of subglacial lake drainage have recently been found beneath the Antarctic ice sheet and tentatively linked to the onset of fast ice flow6,7,8. Here we report an observed acceleration of ice velocity on Byrd Glacier, East Antarctica, of about 10% of the original speed between December 2005 and February 2007. The acceleration extended along the entire 75 km glacier trunk and its onset coincided with the discharge of about 1.7 km3 of water from two large subglacial lakes located about 200 km upstream of the grounding line. Deceleration coincided with the termination of the flood. Our findings provide direct evidence that an active lake drainage system can cause large and rapid changes in glacier dynamics.

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Acknowledgements

We thank C. Swithinbank for providing raw data and maps from his 1961 Antarctic field season. B. Lucchitta and T. Hughes provided us with Landsat TM4 scenes of Byrd Glacier. SPOT images are courtesy of the CNES/SPIRIT program. Research was supported by a NASA ESS fellowship (NNG05-GQ3H) to L.A.S., NSF grant ANT-0636719 to B.E.S. and NASA grant NNG04-GK39G to G.S.H.

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Affiliations

  1. Climate Change Institute, University of Maine, 5790 Bryand Global Science Center, Orono, Maine 04469, USA

    • Leigh A. Stearns
    •  & Gordon S. Hamilton
  2. Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA

    • Benjamin E. Smith

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All authors contributed equally to the manuscript, and approve the version being submitted.

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Correspondence to Leigh A. Stearns.

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https://doi.org/10.1038/ngeo356

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