Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening
Understanding the processes that govern ice shelf extent are of fundamental importance to improved estimates of future sea level rise. In present-day Antarctica, ice shelf extent is most commonly determined by the propagation of through-cutting fractures called ice shelf rifts. Here, I present the f...
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ftcopernicus:oai:publications.copernicus.org:tcd80646 2023-05-15T13:35:08+02:00 Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening Lipovsky, Bradley Paul 2019-10-22 application/pdf https://doi.org/10.5194/tc-2019-232 https://www.the-cryosphere-discuss.net/tc-2019-232/ eng eng doi:10.5194/tc-2019-232 https://www.the-cryosphere-discuss.net/tc-2019-232/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-2019-232 2019-12-24T09:48:18Z Understanding the processes that govern ice shelf extent are of fundamental importance to improved estimates of future sea level rise. In present-day Antarctica, ice shelf extent is most commonly determined by the propagation of through-cutting fractures called ice shelf rifts. Here, I present the first three-dimensional analysis of ice shelf rift propagation. I present a linear elastic fracture mechanical (LEFM) description of rift propagation. The model predicts that rifts may be stabilized when buoyant flexure results in contact at the tops of the near-tip rift walls. This stabilizing tendency may be overcome, however, by processes that act in the ice shelf margins. In particular, both marginal weakening and the advection of rifts into an ice tongue are shown to be processes that may trigger rift propagation. Marginal shear stress is shown to be the determining factor that governs these types of rift instability. I furthermore show that rift stability is closely related to the transition from uniaxial to biaxial extension known as the compressive arch. Although the partial contact of rift walls is fundamentally a three-dimensional process, I demonstrate that it may be parameterized within more numerically efficient two-dimensional calculations. This study provides a step towards a description of calving physics that is based in fracture mechanics. Text Antarc* Antarctica Ice Shelf Copernicus Publications: E-Journals |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Understanding the processes that govern ice shelf extent are of fundamental importance to improved estimates of future sea level rise. In present-day Antarctica, ice shelf extent is most commonly determined by the propagation of through-cutting fractures called ice shelf rifts. Here, I present the first three-dimensional analysis of ice shelf rift propagation. I present a linear elastic fracture mechanical (LEFM) description of rift propagation. The model predicts that rifts may be stabilized when buoyant flexure results in contact at the tops of the near-tip rift walls. This stabilizing tendency may be overcome, however, by processes that act in the ice shelf margins. In particular, both marginal weakening and the advection of rifts into an ice tongue are shown to be processes that may trigger rift propagation. Marginal shear stress is shown to be the determining factor that governs these types of rift instability. I furthermore show that rift stability is closely related to the transition from uniaxial to biaxial extension known as the compressive arch. Although the partial contact of rift walls is fundamentally a three-dimensional process, I demonstrate that it may be parameterized within more numerically efficient two-dimensional calculations. This study provides a step towards a description of calving physics that is based in fracture mechanics. |
format |
Text |
author |
Lipovsky, Bradley Paul |
spellingShingle |
Lipovsky, Bradley Paul Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
author_facet |
Lipovsky, Bradley Paul |
author_sort |
Lipovsky, Bradley Paul |
title |
Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
title_short |
Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
title_full |
Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
title_fullStr |
Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
title_full_unstemmed |
Ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
title_sort |
ice shelf rift propagation: stability, three dimensional effects, and the role of marginal weakening |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-2019-232 https://www.the-cryosphere-discuss.net/tc-2019-232/ |
genre |
Antarc* Antarctica Ice Shelf |
genre_facet |
Antarc* Antarctica Ice Shelf |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2019-232 https://www.the-cryosphere-discuss.net/tc-2019-232/ |
op_doi |
https://doi.org/10.5194/tc-2019-232 |
_version_ |
1766061344873775104 |