@article{205491a607984c48b49d3d5fb80b6747,
title = "Vertical Structure of Diurnal Englacial Hydrology Cycle at Helheim Glacier, East Greenland",
abstract = "The interior dynamics of Helheim Glacier were monitored using an autonomous phase-sensitive radio-echo sounder (ApRES) during two consecutive summers. The return signals from all observational sites exhibited strong non-tidal, depth-dependent diurnal variations. We show that these variations in the glacier interior can be explained by an englacial diurnal meltwater cycle: a data interpretation that assumes constant ice-column composition through time leads to dynamical inconsistencies with concurrent observations from GPS and terrestrial radar. The observed diurnal meltwater cycle is spatially variable, both between different sites and in the vertical, consistent with the existence of a dense and complex englacial hydrologic network. Future applications of this observational technique could reveal long-term meltwater behavior inside glaciers and ice sheets, leading to an improved understanding of the spatiotemporal evolution of the basal boundary conditions needed to simulate them realistically.",
keywords = "ApRES, Helheim Glacier, diurnal cycle, englacial hydrology, glacier dynamics, meltwater",
author = "Irena Va{\v n}kov{\'a} and Denis Voytenko and Nicholls, {Keith W.} and Surui Xie and Parizek, {Byron R.} and Holland, {David M.}",
note = "Funding Information: We are grateful to the support provided from New York University Abu Dhabi through grant G1204, the NASA Jet Propulsion Laboratory Oceans Melting Greenland (OMG) program, and NSF grants ARC-1304137, ANT-0424589, AGS-1338832, and PLR-1443190. DEMs were provided by the Polar Geospatial Center under NSF OPP awards 1043681, 1559691, and 1542736. The GPS and atmospheric data are provided as supporting information. The TRI and ApRES data are too large to be freely stored at a public repository. Therefore, these data are archived at an institutional repository at the New York University{\textquoteright}s Environmental Fluid Dynamics Laboratory server, and they are freely available upon request to efdl@nyu.edu. We thank Brian Rougeux for deploying on-glacier instruments, and Denise Holland for organizing field logistics. UNAVCO is thanked for maintaining the permanent GPS station HEL2, Annie Zaino for helping with the installation of on-glacier GPS receivers, and Brice No{\"e}l for sharing RACMO2.3p2 output. We thank three anonymous reviewers for their insightful feedback. Funding Information: We are grateful to the support provided from New York University Abu Dhabi through grant G1204, the NASA Jet Propulsion Laboratory Oceans Melting Greenland (OMG) program, and NSF grants ARC-1304137, ANT-0424589, AGS-1338832, and PLR-1443190. DEMs were provided by the Polar Geospatial Center under NSF OPP awards 1043681, 1559691, and 1542736. The GPS and atmospheric data are provided as supporting information. The TRI and ApRES data are too large to be freely stored at a public repository. Therefore, these data are archived at an institutional repository at the New York University's Environmental Fluid Dynamics Laboratory server, and they are freely available upon request to efdl@nyu.edu. We thank Brian Rougeux for deploying on-glacier instruments, and Denise Holland for organizing field logistics. UNAVCO is thanked for maintaining the permanent GPS station HEL2, Annie Zaino for helping with the installation of on-glacier GPS receivers, and Brice No?l for sharing RACMO2.3p2 output. We thank three anonymous reviewers for their insightful feedback. Publisher Copyright: {\textcopyright}2018. American Geophysical Union. All Rights Reserved.",
year = "2018",
month = aug,
day = "28",
doi = "10.1029/2018GL077869",
language = "English (US)",
volume = "45",
pages = "8352--8362",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "16",
}