Crystal orientation fabric anisotropy causes directional hardening of the Northeast Greenland Ice Stream

Tamara Annina Gerber*, David A Lilien, Nicholas Mossor Rathmann, Steven Franke, Tun Jan Young, Fernando Valero-Delgado, M Reza Ershadi, Reinhard Drews, Ole Zeising, Angelika Humbert, Nicolas Stoll, Ilka Weikusat, Aslak Grinsted, Christine Schøtt Hvidberg, Daniela Jansen, Heinrich Miller, Veit Helm, Daniel Steinhage, Charles O'Neill, John PadenSiva Prasad Gogineni, Dorthe Dahl-Jensen, Olaf Eisen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The dynamic mass loss of ice sheets constitutes one of the biggest uncertainties in projections of ice-sheet evolution. One central, understudied aspect of ice flow is how the bulk orientation of the crystal orientation fabric translates to the mechanical anisotropy of ice. Here we show the spatial distribution of the depth-averaged horizontal anisotropy and corresponding directional flow-enhancement factors covering a large area of the Northeast Greenland Ice Stream onset. Our results are based on airborne and ground-based radar surveys, ice-core observations, and numerical ice-flow modelling. They show a strong spatial variability of the horizontal anisotropy and a rapid crystal reorganisation on the order of hundreds of years coinciding with the ice-stream geometry. Compared to isotropic ice, parts of the ice stream are found to be more than one order of magnitude harder for along-flow extension/compression while the shear margins are potentially softened by a factor of two for horizontal-shear deformation.

Original languageEnglish
Article number2653
Number of pages12
JournalNature Communications
Volume14
DOIs
Publication statusPublished - 8 May 2023

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