Implications of initial conditions and ice-ocean coupling for grounding-line evolution

Byron R. Parizek, Ryan T. Walker

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Ice-sheet grounding lines are sensitive to initial conditions and to small perturbations in boundary conditions, based on new model results coupling ocean and ice flow. To study ice-ocean dynamics near ice-stream grounding lines, we couple an ocean-plume model that simulates ice-shelf basal melting with a two-dimensional, isothermal model of ice-stream and ice-shelf flow. The notable results of the coupled model experiments are to reveal grounding-line migration sensitivities to i) specific aspects of modeling-derived and history-dependent initial conditions, ii) to the overall melt magnitude, and iii) to a positive feedback between focused melting and local slopes of basal ice that is eventually stabilized by buttressing for lengthening ice shelves. These interactions can lead to multiple steady states for ice flow over a bed that shallows in the along-flow direction and have an important bearing on the effects of bedrock bumps.When in the vicinity of bedrock highs, grounding lines tend to rapidly advance or retreat towards the basal asperity. A significant delay or cessation of (de)glaciation occurs once the grounding line reaches the leeward side of the bedrock crest. However, while bedrock bumps can offer stability in the grounding zone, minor changes in ocean conditions can easily offset their effect through basal melting feedbacks.

Original languageEnglish (US)
Pages (from-to)351-358
Number of pages8
JournalEarth and Planetary Science Letters
Volume300
Issue number3-4
DOIs
StatePublished - Dec 1 2010

Fingerprint

grounding line
Ice
Electric grounding
oceans
ice
bedrock
ice shelf
land ice
basal melting
ocean
ice stream
ice flow
melting
basal ice
Melting
asperity
ocean dynamics
glaciation
ice sheet
positive feedback

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

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abstract = "Ice-sheet grounding lines are sensitive to initial conditions and to small perturbations in boundary conditions, based on new model results coupling ocean and ice flow. To study ice-ocean dynamics near ice-stream grounding lines, we couple an ocean-plume model that simulates ice-shelf basal melting with a two-dimensional, isothermal model of ice-stream and ice-shelf flow. The notable results of the coupled model experiments are to reveal grounding-line migration sensitivities to i) specific aspects of modeling-derived and history-dependent initial conditions, ii) to the overall melt magnitude, and iii) to a positive feedback between focused melting and local slopes of basal ice that is eventually stabilized by buttressing for lengthening ice shelves. These interactions can lead to multiple steady states for ice flow over a bed that shallows in the along-flow direction and have an important bearing on the effects of bedrock bumps.When in the vicinity of bedrock highs, grounding lines tend to rapidly advance or retreat towards the basal asperity. A significant delay or cessation of (de)glaciation occurs once the grounding line reaches the leeward side of the bedrock crest. However, while bedrock bumps can offer stability in the grounding zone, minor changes in ocean conditions can easily offset their effect through basal melting feedbacks.",
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Implications of initial conditions and ice-ocean coupling for grounding-line evolution. / Parizek, Byron R.; Walker, Ryan T.

In: Earth and Planetary Science Letters, Vol. 300, No. 3-4, 01.12.2010, p. 351-358.

Research output: Contribution to journalArticle

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