Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies
Sea ice is an essential component of the climate system because it modulates the exchange of energy between the ocean and the atmosphere. Under stress from wind and ocean currents, sea ice deforms constantly. Sea ice deformation takes the shape of narrow lines, the Linear Kinematic Features (LKFs)....
Main Author: | |
---|---|
Other Authors: | , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Universität Bremen
2020
|
Subjects: | |
Online Access: | https://media.suub.uni-bremen.de/handle/elib/4583 https://doi.org/10.26092/elib/380 https://nbn-resolving.org/urn:nbn:de:gbv:46-elib45837 |
id |
ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/4583 |
---|---|
record_format |
openpolar |
spelling |
ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/4583 2023-05-15T15:17:31+02:00 Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies Ringeisen, Damien Haas, Christian Jung, Thomas 2020-09-04 application/pdf https://media.suub.uni-bremen.de/handle/elib/4583 https://doi.org/10.26092/elib/380 https://nbn-resolving.org/urn:nbn:de:gbv:46-elib45837 eng eng Universität Bremen Fachbereich 01: Physik/Elektrotechnik (FB 01) https://media.suub.uni-bremen.de/handle/elib/4583 http://dx.doi.org/10.26092/elib/380 doi:10.26092/elib/380 urn:nbn:de:gbv:46-elib45837 info:eu-repo/semantics/openAccess Attribution 3.0 Germany http://creativecommons.org/licenses/by/3.0/de/ CC-BY sea ice rheology viscous plastic modelling arctic LKF high-resolution numerical simulation fracture angles coulombic friction yield curve plastic potential flow rule model climate climate change banquise ocean dilatancy granular 530 530 Physics ddc:530 Dissertation doctoralThesis 2020 ftsubbremen https://doi.org/10.26092/elib/380 2022-11-09T07:10:13Z Sea ice is an essential component of the climate system because it modulates the exchange of energy between the ocean and the atmosphere. Under stress from wind and ocean currents, sea ice deforms constantly. Sea ice deformation takes the shape of narrow lines, the Linear Kinematic Features (LKFs). LKFs influence the heat transfer, mass balance, and sea ice dynamics, so LKFs should be accurately represented in high-resolution climate models. Sea ice is commonly modeled using viscous-plastic (VP) rheologies defined by a yield curve and a flow rule. Recent work showed that VP sea ice models explicitly create LKFs but overestimate their intersection angles. This thesis aims to investigate the link between the angles of fracture in sea ice models and the parametrization of the sea ice internal stresses using idealized compression experiments. Three questions are addressed: Which parameters of the VP rheologies influence the fracture angle? Which theoretical framework explains this influence? Which rheologies should be used to simulate intersection angles at the observed range? With the commonly used standard VP rheology with an elliptical yield curve and a normal flow rule, the fracture angles are linked to the yield curve's elliptical shape. Because of this shape, this rheology cannot create sea ice fracture angles more acute than 30 degrees in uniaxial compression, even by changing the aspect of the ellipse. The classical coulombic theory predicts the angle of fracture accurately when adapted to the context of sea ice modeling. A new rheology with an elliptical yield curve and a non-normal flow rule shows that fracture angles are also sensitive to the orientation of the flow rule. Using this new rheology allows creating fracture angles as low as 22 degrees in uniaxial compression. A theory based on the angle of dilatancy and observations of granular materials predicts precisely the simulated angles. Alternative rheologies can create fracture angles lower than 30 degrees. With Mohr--Coulomb yield curves, fracture ... Doctoral or Postdoctoral Thesis Arctic banquise Climate change Sea ice Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) Arctic |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
sea ice rheology viscous plastic modelling arctic LKF high-resolution numerical simulation fracture angles coulombic friction yield curve plastic potential flow rule model climate climate change banquise ocean dilatancy granular 530 530 Physics ddc:530 |
spellingShingle |
sea ice rheology viscous plastic modelling arctic LKF high-resolution numerical simulation fracture angles coulombic friction yield curve plastic potential flow rule model climate climate change banquise ocean dilatancy granular 530 530 Physics ddc:530 Ringeisen, Damien Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
topic_facet |
sea ice rheology viscous plastic modelling arctic LKF high-resolution numerical simulation fracture angles coulombic friction yield curve plastic potential flow rule model climate climate change banquise ocean dilatancy granular 530 530 Physics ddc:530 |
description |
Sea ice is an essential component of the climate system because it modulates the exchange of energy between the ocean and the atmosphere. Under stress from wind and ocean currents, sea ice deforms constantly. Sea ice deformation takes the shape of narrow lines, the Linear Kinematic Features (LKFs). LKFs influence the heat transfer, mass balance, and sea ice dynamics, so LKFs should be accurately represented in high-resolution climate models. Sea ice is commonly modeled using viscous-plastic (VP) rheologies defined by a yield curve and a flow rule. Recent work showed that VP sea ice models explicitly create LKFs but overestimate their intersection angles. This thesis aims to investigate the link between the angles of fracture in sea ice models and the parametrization of the sea ice internal stresses using idealized compression experiments. Three questions are addressed: Which parameters of the VP rheologies influence the fracture angle? Which theoretical framework explains this influence? Which rheologies should be used to simulate intersection angles at the observed range? With the commonly used standard VP rheology with an elliptical yield curve and a normal flow rule, the fracture angles are linked to the yield curve's elliptical shape. Because of this shape, this rheology cannot create sea ice fracture angles more acute than 30 degrees in uniaxial compression, even by changing the aspect of the ellipse. The classical coulombic theory predicts the angle of fracture accurately when adapted to the context of sea ice modeling. A new rheology with an elliptical yield curve and a non-normal flow rule shows that fracture angles are also sensitive to the orientation of the flow rule. Using this new rheology allows creating fracture angles as low as 22 degrees in uniaxial compression. A theory based on the angle of dilatancy and observations of granular materials predicts precisely the simulated angles. Alternative rheologies can create fracture angles lower than 30 degrees. With Mohr--Coulomb yield curves, fracture ... |
author2 |
Haas, Christian Jung, Thomas |
format |
Doctoral or Postdoctoral Thesis |
author |
Ringeisen, Damien |
author_facet |
Ringeisen, Damien |
author_sort |
Ringeisen, Damien |
title |
Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
title_short |
Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
title_full |
Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
title_fullStr |
Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
title_full_unstemmed |
Fracture Angles in Numerical Simulations of Sea Ice with Viscous-Plastic Rheologies |
title_sort |
fracture angles in numerical simulations of sea ice with viscous-plastic rheologies |
publisher |
Universität Bremen |
publishDate |
2020 |
url |
https://media.suub.uni-bremen.de/handle/elib/4583 https://doi.org/10.26092/elib/380 https://nbn-resolving.org/urn:nbn:de:gbv:46-elib45837 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic banquise Climate change Sea ice |
genre_facet |
Arctic banquise Climate change Sea ice |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/4583 http://dx.doi.org/10.26092/elib/380 doi:10.26092/elib/380 urn:nbn:de:gbv:46-elib45837 |
op_rights |
info:eu-repo/semantics/openAccess Attribution 3.0 Germany http://creativecommons.org/licenses/by/3.0/de/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.26092/elib/380 |
_version_ |
1766347759148859392 |