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Crystal orientation fabric anisotropy causes directional hardening of the Northeast Greenland Ice Stream
Gerber, Tamara Annina Lilien, David A. Rathmann, Nicholas Mossor Franke, Steven Young, Tun Jan Valero-Delgado, Fernando Ershadi, M. Reza Drews, Reinhard Zeising, Ole Humbert, Angelika
Gerber, Tamara Annina
Lilien, David A.
Rathmann, Nicholas Mossor
Franke, Steven
Young, Tun Jan
Valero-Delgado, Fernando
Ershadi, M. Reza
Drews, Reinhard
Zeising, Ole
Humbert, Angelika
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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.
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Date
2023-05-08
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Nature Research
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Keywords
Projection and prediction, Geophysics, Cryospheric science
Citation
Gerber, T. A., Lilien, D. A., Rathmann, N. M., Franke, S., Young, T. J., Valero-Delgado, F., Ershadi, M. R., Drews, R., Zeising, O., Humbert, A., Stoll, N., Weikusat, I., Grinsted, A., Hvidberg, C. S., Jansen, D., Miller, H., Helm, V., Steinhage, D., O'Neill, C., Paden, J., … Eisen, O. (2023). Crystal orientation fabric anisotropy causes directional hardening of the Northeast Greenland Ice Stream. Nature communications, 14(1), 2653. https://doi.org/10.1038/s41467-023-38139-8