@article{ed81e8eff44147089c7ed24eb87071f6,
title = "Enhanced Firn Densification in High-Accumulation Shear Margins of the NE Greenland Ice Stream",
abstract = "Firn thickness across the NE Greenland Ice Stream is a function of accumulated strain, with thinner firn in the high-strain margins of the ice stream. We present a novel technique for extracting firn density from previously collected seismic reflection profiles and apply this technique across both shear margins of NE Greenland Ice Stream. Firn is up to 30 m thinner in the vicinity of the ice stream shear margins. Snow accumulation rates across the ice stream were calculated from airborne ice-penetrating radar data, calibrated with ground-based firn density measurements from a shallow core. We find that accumulation is ~20% higher in the shear margins compared to the surroundings. The higher density firn adjacent to shear margins is due to high along-flow stresses that accelerate firn densification and develops despite the higher accumulation rate favoring lower density. These firn density variations influence subglacial hydropotential by changing the ice surface slope and overburden pressure and may influence subglacial water flow. These results demonstrate the importance of high-resolution firn surveys in studies of shear-margin dynamics.",
author = "Riverman, {K. L.} and Alley, {R. B.} and S. Anandakrishnan and K. Christianson and Holschuh, {N. D.} and B. Medley and A. Muto and Peters, {L. E.}",
note = "Funding Information: K. R. and N. H. were supported by the National Science Foundation Graduate Research Fellowship under grant DGE1255832, with additional funding from Penn State Department of Geosciences and the Evan Pugh Endowment. K. C. and N. D. H. were supported by NASA grant NNX16AM01G. L. E. P. was supported by the Australian Research Council's Special Research Initiative for Antarctic Gateway Partnership (project ID SR140300001). All authors received support from NSF grant OPP‐0424589. The Polar Geospatial Center provided high‐resolution digital elevation models. UNAVCO provided GPS base station data. Logistical support was provided by CH2MHILL Polar Services, the New York Air National Guard, Kenn Borek Air, the Alfred Wegener Institute for Polar and Marine Research, and the North Greenland Eemian Ice Drilling Project. We thank B. Parizek for valuable conversations and two anonymous reviewers whose detailed comments improved our manuscript immensely. Seismic and surface elevation data available at doi. org/10.5281/zenodo.1345804. Funding Information: K. R. and N. H. were supported by the National Science Foundation Graduate Research Fellowship under grant DGE1255832, with additional funding from Penn State Department of Geosciences and the Evan Pugh Endowment. K. C. and N. D. H. were supported by NASA grant NNX16AM01G. L. E. P. was supported by the Australian Research Council's Special Research Initiative for Antarctic Gateway Partnership (project ID SR140300001). All authors received support from NSF grant OPP-0424589. The Polar Geospatial Center provided high-resolution digital elevation models. UNAVCO provided GPS base station data. Logistical support was provided by CH2MHILL Polar Services, the New York Air National Guard, Kenn Borek Air, the Alfred Wegener Institute for Polar and Marine Research, and the North Greenland Eemian Ice Drilling Project. We thank B. Parizek for valuable conversations and two anonymous reviewers whose detailed comments improved our manuscript immensely. Seismic and surface elevation data available at doi.org/10.5281/zenodo.1345804. Publisher Copyright: {\textcopyright}2018. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = feb,
doi = "10.1029/2017JF004604",
language = "English (US)",
volume = "124",
pages = "365--382",
journal = "Journal of Geophysical Research: Earth Surface",
issn = "2169-9003",
number = "2",
}