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  From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model

Feldmann, J., Levermann, A. (2017): From cyclic ice streaming to Heinrich-like events: the grow-and-surge instability in the Parallel Ice Sheet Model. - The Cryosphere, 11, 4, 1913-1932.
https://doi.org/10.5194/tc-11-1913-2017

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 Creators:
Feldmann, Johannes1, Author              
Levermann, Anders1, Author              
Affiliations:
1Potsdam Institute for Climate Impact Research, ou_persistent13              

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Free keywords: SPP 1158
 Abstract: Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolution includes an enthalpy-based formulation of the thermodynamics, a nonlinear stress-balance-based sliding law and a very simple subglacial hydrology. The simulated unforced surging is characterized by rapid ice streaming through a bed trough, resulting in abrupt discharge of ice across the grounding line which is eventually calved into the ocean. We visualize the central feedbacks that dominate the subsequent phases of ice buildup, surge and stabilization which emerge from the interaction between ice dynamics, thermodynamics and the subglacial till layer. Results from the variation of surface mass balance and basal roughness suggest that ice sheets of medium thickness may be more susceptible to surging than relatively thin or thick ones for which the surge feedback loop is damped. We also investigate the influence of different basal sliding laws (ranging from purely plastic to nonlinear to linear) on possible surging. The presented mechanisms underlying our simulations of self-maintained, periodic ice growth and destabilization may play a role in large-scale ice-sheet surging, such as the surging of the Laurentide Ice Sheet, which is associated with Heinrich events, and ice-stream shutdown and reactivation, such as observed in the Siple Coast region of West Antarctica.

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 Dates: 2017
 Publication Status: Finally published
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.5194/tc-11-1913-2017
PIKDOMAIN: Earth System Analysis - Research Domain I
PIKDOMAIN: Sustainable Solutions - Research Domain III
eDoc: 7320
Research topic keyword: Ice
Research topic keyword: Nonlinear Dynamics
Research topic keyword: Tipping Elements
Model / method: PISM-PIK
Regional keyword: Arctic & Antarctica
Organisational keyword: RD1 - Earth System Analysis
Organisational keyword: RD4 - Complexity Science
Working Group: Ice Dynamics
Working Group: Ice Dynamics
 Degree: -

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Title: The Cryosphere
Source Genre: Journal, SCI, Scopus, p3, oa
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Pages: - Volume / Issue: 11 (4) Sequence Number: - Start / End Page: 1913 - 1932 Identifier: CoNE: https://publications.pik-potsdam.de/cone/journals/resource/140507