Rate-and-state friction explains glacier surge propagation

Kjetil Thøgersen; Adrien Gilbert; Thomas Vikhamar Schuler; Anders Malthe-Sørenssen

doi:10.1038/s41467-019-10506-4

Rate-and-state friction explains glacier surge propagation

Nat Commun. 2019 Jun 27;10(1):2823. doi: 10.1038/s41467-019-10506-4.

Authors

Kjetil Thøgersen^{1

2}, Adrien Gilbert³, Thomas Vikhamar Schuler³, Anders Malthe-Sørenssen^{4

5}

Affiliations

¹ Physics of Geological Processes, The NJORD Centre, University of Oslo, 0316, Oslo, Norway. kjetil.thogersen@fys.uio.no.
² Department of Geosciences, University of Oslo, 0316, Oslo, Norway. kjetil.thogersen@fys.uio.no.
³ Department of Geosciences, University of Oslo, 0316, Oslo, Norway.
⁴ Physics of Geological Processes, The NJORD Centre, University of Oslo, 0316, Oslo, Norway.
⁵ Department of Physics, University of Oslo, 0316, Oslo, Norway.

Abstract

The incomplete understanding of glacier dynamics is a major source of uncertainty in assessments of sea-level rise from land-based ice. Through increased ice discharge into the oceans, accelerating glacier flow has the potential to considerably enhance expected sea-level change, well ahead of scenarios considered by the IPCC. Central in our incomplete understanding is the motion at the glacier bed, responsible for flow transients and instabilities involving switches from slow to fast flow. We introduce a rate-and-state framework for the transient evolution of basal shear stress, which we incorporate in glacier simulations. We demonstrate that a velocity-strengthening-weakening transition combined with a characteristic length scale for the opening of subglacial cavities is sufficient to reproduce several previously unexplained features of glacier surges. The rate-and-state framework opens for new ways to analyze, understand and predict transient glacier dynamics as well as to assess the stability of glaciers and ice caps.