1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964-8000, USA
2. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
3. Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824, USA
4. Applied Physics Lab, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105-6698, USA

Correspondence to: Robin E. Bell¹ Correspondence and requests for materials should be addressed to R.E.B. (Email: robinb@ldeo.columbia.edu).

Abstract

Water plays a crucial role in ice-sheet stability and the onset of ice streams. Subglacial lake water moves between lakes¹ and rapidly drains, causing catastrophic floods². The exact mechanisms by which subglacial lakes influence ice-sheet dynamics are unknown, however, and large subglacial lakes^{3, 4} have not been closely associated with rapidly flowing ice streams. Here we use satellite imagery and ice-surface elevations to identify a region of subglacial lakes, similar in total area to Lake Vostok, at the onset region of the Recovery Glacier ice stream in East Antarctica and predicted by ice-sheet models⁵. We define four lakes through extensive, flat, featureless regions of ice surface bounded by upstream troughs and downstream ridges. Using ice velocities determined using interferometric synthetic aperture radar (InSAR), we find the onset of rapid flow (moving at 20 to 30 m yr^-1) of the tributaries to the Recovery Glacier ice stream in a 280-km-wide segment at the downslope margins of these four subglacial lakes. We conclude that the subglacial lakes initiate and maintain rapid ice flow through either active modification of the basal thermal regime of the ice sheet by lake accretion or through scouring bedrock channels in periodic drainage events. We suggest that the role of subglacial lakes needs to be considered in ice-sheet mass balance assessments.

1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964-8000, USA
2. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
3. Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824, USA
4. Applied Physics Lab, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105-6698, USA

Correspondence to: Robin E. Bell¹ Correspondence and requests for materials should be addressed to R.E.B. (Email: robinb@ldeo.columbia.edu).

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