Sliding dominates slow-flowing margin regions, Greenland Ice Sheet

Nathan Maier, Neil Humphrey, Joel Harper, Toby Meierbachtol

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

On the Greenland Ice Sheet (GrIS), ice flow due to deformation and sliding across the bed delivers ice to lower-elevation marginal regions where it can melt. We measured the two mechanisms of motion using a three-dimensional array of 212 tilt sensors installed within a network of boreholes drilled to the bed in the ablation zone of GrIS. Unexpectedly, sliding completely dominates ice motion all winter, despite a hard bedrock substrate and no concurrent surface meltwater forcing. Modeling constrained by detailed tilt observations made along the basal interface suggests that the high sliding is due to a slippery bed, where sparsely spaced bedrock bumps provide the limited resistance to sliding. The conditions at the site are characterized as typical of ice sheet margins; thus, most ice flow near the margins of GrIS is mainly from sliding, and marginal ice fluxes are near their theoretical maximum for observed surface speeds.

Original languageEnglish
Article numbereaaw5406
JournalScience advances
Volume5
Issue number7
DOIs
StatePublished - 2019

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