Boundary conditions of an active West Antarctic subglacial lake

implications for storage of water beneath the ice sheet

M. J. Siegert, N. Ross, H. Corr, B. Smith, T. Jordan, R. Bingham, F. Ferraccioli, D. Rippin, A. Le Brocq

Research output: Contribution to journalArticle

Abstract

Repeat-pass IceSat altimetry has revealed 124 discrete surface height changes across the Antarctic Ice Sheet, interpreted to be caused by subglacial lake discharges (surface lowering) and inputs (surface uplift). Few of these active lakes have been confirmed by radio-echo sounding (RES) despite several attempts (notable exceptions are Lake Whillans and three in the Adventure Subglacial Trench). Here we present targeted RES and radar altimeter data from an "active lake" location within the upstream Institute Ice Stream, into which 0.12 km3 of water is calculated to have flowed between October 2003 and February 2008. We use a series of transects to establish an accurate appreciation of the influences of bed topography and ice-surface elevation on water storage potential. The location of surface height change is over the downslope flank of a distinct topographic hollow, where RES reveals no obvious evidence for deep (> 10 m) water. The regional hydropotential reveals a sink coincident with the surface change, however. Governed by the location of the hydrological sink, basal water will likely "drape" over existing topography in a manner dissimilar to subglacial lakes where flat strong specular RES reflections are measured. The inability of RES to detect the active lake means that more of the Antarctic ice sheet bed may contain stored water than is currently appreciated. Variation in ice surface elevation datasets leads to significant alteration in calculations of the local flow of basal water indicating the value of, and need for, high resolution RES datasets in both space and time to establish and characterise subglacial hydrological processes
Original languageEnglish
Pages (from-to)2979-2999
Number of pages20
JournalThe Cryosphere Discussions
Volume7
DOIs
Publication statusPublished - 2013

Fingerprint

echo sounding
ice sheet
boundary condition
radio
lake
water
topography
ice
ice stream
altimetry
altimeter
water storage
trench
transect
uplift
radar

Keywords

  • subglacial lakes
  • antarctica
  • hydrology

Cite this

Boundary conditions of an active West Antarctic subglacial lake : implications for storage of water beneath the ice sheet. / Siegert, M. J.; Ross, N.; Corr, H. ; Smith, B.; Jordan, T.; Bingham, R.; Ferraccioli, F.; Rippin, D.; Le Brocq, A. .

In: The Cryosphere Discussions, Vol. 7, 2013, p. 2979-2999.

Research output: Contribution to journalArticle

Siegert, MJ, Ross, N, Corr, H, Smith, B, Jordan, T, Bingham, R, Ferraccioli, F, Rippin, D & Le Brocq, A 2013, 'Boundary conditions of an active West Antarctic subglacial lake: implications for storage of water beneath the ice sheet', The Cryosphere Discussions, vol. 7, pp. 2979-2999. https://doi.org/10.5194/tcd-7-2979-2013
Siegert, M. J. ; Ross, N. ; Corr, H. ; Smith, B. ; Jordan, T. ; Bingham, R. ; Ferraccioli, F. ; Rippin, D. ; Le Brocq, A. . / Boundary conditions of an active West Antarctic subglacial lake : implications for storage of water beneath the ice sheet. In: The Cryosphere Discussions. 2013 ; Vol. 7. pp. 2979-2999.
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