TY - JOUR
T1 - Subglacial Lake Whillans - Ice-penetrating radar and GPS observations of a shallow active reservoir beneath a West Antarctic ice stream
AU - Christianson, Knut
AU - Jacobel, Robert W.
AU - Horgan, Huw J.
AU - Anandakrishnan, Sridhar
AU - Alley, Richard B.
N1 - Funding Information:
This experiment was carried out as part of the WISSARD program funded by the American Recovery and Reinvestment Act of 2009 through the National Science Foundation ( NSF OPP 0838854 , 0838855 , 0838763 , 0838764 ). The Center for Remote Sensing of Ice Sheets ( NSF OPP 0424589 ) and NASA grant NNX10AI04G also partially funded this study. KC was supported by a US-NSF graduate research fellowship. We thank David Heeszel, Mauro Pavan, Stefano Picotti, and Jacob Walter for help with the field program. Undergraduate students Rebecca Gobel, Benjamin Keisling, Karl Lapo, and Lauren Snyder at St. Olaf College assisted with parts of radar data processing. GPS data were obtained from UNAVCO and SOPAC. NSIDC provided ICESat and MODIS MOA data. We thank Ian Joughin for velocity data and Helen Fricker and Ted Scambos for outlines of subglacial lakes derived from remote-sensing data. Logistical support was provided by Raytheon Polar Services, the New York Air National Guard, and Kenn Borek Air. This manuscript was improved by the comments of two anonymous reviewers.
PY - 2012/5/15
Y1 - 2012/5/15
N2 - Ice-penetrating radar and kinematic GPS observations from Subglacial Lake Whillans (SLW), West Antarctica, reveal a shallow lake that is confined by steep basal topographic features. Radar imaging of SLW, although indicating wet basal conditions, is consistent with a water column depth of only ~. 6. m or less during the near low-stand state at the time of the survey. Kinematic GPS profiles reveal that SLW is generally defined by a ~. 15. m surface depression centered at S 84.237° W 153.614°. This point coincides with the area of lowest hydropotential in the lake basin and also the largest surface elevation range in ICESat data. Therefore this location appears to be an opportune site for subglacial access drilling of this active subglacial lake. A distinct basal topographic ridge on the grid south side of the basin is coincident with a strong contrast in relative basal reflectivity (~. 6. dB), which we interpret as the lake boundary. Mapped hydropotential (calculated assuming hydrostatic equilibrium) shows that water enters the lake from the upstream direction and drains downstream. We hypothesize that a lake-level rise of ~. 5. m plus flexural effects is sufficient to overtop a drainage divide. Thus SLW acts as a temporary storage basin for water beneath Whillans Ice Stream.
AB - Ice-penetrating radar and kinematic GPS observations from Subglacial Lake Whillans (SLW), West Antarctica, reveal a shallow lake that is confined by steep basal topographic features. Radar imaging of SLW, although indicating wet basal conditions, is consistent with a water column depth of only ~. 6. m or less during the near low-stand state at the time of the survey. Kinematic GPS profiles reveal that SLW is generally defined by a ~. 15. m surface depression centered at S 84.237° W 153.614°. This point coincides with the area of lowest hydropotential in the lake basin and also the largest surface elevation range in ICESat data. Therefore this location appears to be an opportune site for subglacial access drilling of this active subglacial lake. A distinct basal topographic ridge on the grid south side of the basin is coincident with a strong contrast in relative basal reflectivity (~. 6. dB), which we interpret as the lake boundary. Mapped hydropotential (calculated assuming hydrostatic equilibrium) shows that water enters the lake from the upstream direction and drains downstream. We hypothesize that a lake-level rise of ~. 5. m plus flexural effects is sufficient to overtop a drainage divide. Thus SLW acts as a temporary storage basin for water beneath Whillans Ice Stream.
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U2 - 10.1016/j.epsl.2012.03.013
DO - 10.1016/j.epsl.2012.03.013
M3 - Article
AN - SCOPUS:84859648508
SN - 0012-821X
VL - 331-332
SP - 237
EP - 245
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -