10 Nov 2021

10 Nov 2021

Review status: this preprint is currently under review for the journal TC.

Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds

Whyjay Zheng1,2 Whyjay Zheng
  • 1Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA
  • 2Department of Statistics, University of California Berkeley, Berkeley, CA, USA

Abstract. Basal conditions directly control the glacier sliding rate and the dynamic discharge of ice flow. Recent glacier destabilization events indicate that some marine-terminating glaciers quickly respond to lubricated beds with increased flow speed, but the underlying physics, especially how this vulnerability relates to glacier geometry and flow characteristics, remains unclear. This paper presents a 1-D physical framework for glacier dynamic vulnerability assuming sudden basal lubrication as an initial perturbation. In this new model, two quantities determine the scale and the areal extent of the subsequent thinning and acceleration after the bed is lubricated: Péclet number (Pe) and the product of glacier speed and thickness gradient (dubbed J0 in this study). To validate the model, this paper calculates Pe and J0 using multi-sourced data from 1996–1998 for outlet glaciers in Greenland and Austfonna Ice Cap, Svalbard, and compares the results with the glacier speed change during 1996/1998–2018. Glaciers with lower Pe and J0 are more likely to accelerate during this 20-year span than those with higher Pe and J0, which matches the model prediction. A combined factor of ice thickness, surface slope, and initial speed for ice flow physically determines how much and how fast glaciers respond to lubricated beds, as forms of speed, elevation, and terminus change.

Whyjay Zheng

Status: open (until 05 Jan 2022)

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Whyjay Zheng

Data sets

whyjz/pejzero: Pejzero v0.1 -- Supplemental materials presented in "Glacier geometry and flow speed determine how Arctic marine-terminating glaciers respond to lubricated beds" Whyjay Zheng

Whyjay Zheng


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Short summary
A glacier can speed up when surface water reaches the glacier's bottom via crevasses and reduces sliding friction. This paper builds up a physical model and finds that thick and fast-flowing glaciers are sensitive to this friction disruption. The data from Greenland and Austfonna (Svalbard) glaciers over 20 years support the model prediction. These sensitive glaciers should be frequently monitored for potential future instabilities to estimate the projected sea-level rise better.