Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
doi:10.5194/tc-2016-208
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Sep 2016
Review status
A revision of this discussion paper was accepted for the journal The Cryosphere (TC).
Water Content of Greenland Ice Estimated from Ground Radar and Borehole Measurements
Joel Brown1,2, Joel Harper2, and Neil Humphrey3 1Aesir Consulting LLC, Missoula, Montana, 59801, USA
2Department of Geosciences, University of Montana, Missoula, Montana, 59801, USA
3Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming, 82071, USA
Abstract. Liquid water content (wetness) within glacier ice is known to strongly control ice viscosity and ice deformation processes. Little is known about wetness of ice on the outer flanks of the Greenland ice sheet, where a temperate layer of basal ice exists. This study integrates borehole and radar surveys to provide direct estimates of englacial ice wetness in the ablation zone of western Greenland. We estimate electromagnetic propagation velocity of the ice body by inverting reflection traveltimes from radar data. Our inversion is constrained by ice thickness measured in boreholes and by positioning of a temperate/cold ice boundary identified in boreholes. Electromagnetic propagation velocities are consistent with a depth-averaged wetness of ~ 0.5–1.1 %. The inversion indicates that wetness within the ice varies from < 0.1 % in an upper cold layer to ~ 2.9–4.6 % in a 130–150 m thick temperate layer located above the glacier bed. Such high wetness should yield high rates of shear strain.

Citation: Brown, J., Harper, J., and Humphrey, N.: Water Content of Greenland Ice Estimated from Ground Radar and Borehole Measurements, The Cryosphere Discuss., doi:10.5194/tc-2016-208, in review, 2016.
Joel Brown et al.
Joel Brown et al.

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Short summary
We use ground penetrating radar surveys in conjunction with borehole depth and temperature data to estimate the liquid water content (wetness) of glacial ice in the ablation zone of an outlet glacier on the western side of the Greenland Ice Sheet. Our results show that the wetness of a warm basal ice layer is approximately 2.9 % to 4.6 % in our study region. This high level of wetness requires special attention when modeling ice dynamics or estimating ice thickness in the region.
We use ground penetrating radar surveys in conjunction with borehole depth and temperature data...
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