Controls on Water Storage and Drainage in Crevasses on the Greenland Ice Sheet

T. R. Chudley*, P. Christoffersen, S. H. Doyle, T. P.F. Dowling, R. Law, C. M. Schoonman, M. Bougamont, B. Hubbard

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

Surface crevasses on the Greenland Ice Sheet (GrIS) capture nearly half of the seasonal runoff, yet their role in transferring meltwater to the bed has received little attention relative to that of supraglacial lakes and moulins. Here, we present observations of crevasse ponding and investigate controls on their hydrological behavior at a fast-moving, marine-terminating sector of the GrIS. We map surface meltwater, crevasses, and surface-parallel stress across a ∼2,700 km2 region using satellite data and contemporaneous uncrewed aerial vehicle (UAV) surveys. From 2017 to 2019 an average of 26% of the crevassed area exhibited ponding at locations that remained persistent between years despite rapid advection. We find that the spatial distribution of ponded crevasses does not relate to previously proposed controls on the distribution of supraglacial lakes (elevation and topography) or crevasses (von Mises stress thresholds), suggesting the operation of some other physical control(s). Ponded crevasse fields were preferentially located in regions of compressive surface-parallel mean stress, which we interpret to result from the hydraulic isolation of these systems. This contrasts with unponded crevasse fields, which we suggest are readily able to transport meltwater into the wider supraglacial and englacial network. UAV observations show that ponded crevasses can drain episodically and rapidly, likely through hydrofracture. We therefore propose that the surface stress regime influences a spatially heterogeneous transfer of meltwater through crevasses to the bed of ice sheets, with consequences for processes, such as subglacial drainage and the heating of ice via latent heat release by refreezing meltwater.

Original languageEnglish
Article numbere2021JF006287
Number of pages18
JournalJournal of Geophysical Research: Earth Surface
Volume126
Issue number9
DOIs
Publication statusPublished - 06 Sept 2021

Keywords

  • crevasses
  • glacier
  • greenland
  • ice sheet
  • remote sensing
  • supraglacial hydrology
  • Comets
  • Geomorphology: general
  • Permafrost
  • GLOBAL CHANGE
  • Remote sensing
  • Geomorphology and weathering
  • Cryobiology
  • Comets: dust tails and trails
  • Asteroids
  • Permafrost, cryosphere, and high‐latitude processes
  • Weathering
  • Natural hazards
  • HYDROLOGY
  • Research Article
  • BIOGEOSCIENCES
  • Ice sheets
  • Ponds
  • NATURAL HAZARDS
  • PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS
  • Geomorphology: fluvial
  • CRYOSPHERE
  • Geomorphology: hillslope
  • Other
  • PLANETARY SCIENCES: COMETS AND SMALL BODIES

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