Inferred basal friction and mass flux affected by crystal-orientation fabrics
We investigate the errors caused by neglecting the crystal-orientation fabric when inferring the basal friction coefficient field, and whether such errors can be alleviated by inferring an isotropic enhancement factor field to compensate for missing fabric information. We calculate the steady states...
Published in: | Journal of Glaciology |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2022
|
Subjects: | |
Online Access: | https://curis.ku.dk/portal/da/publications/inferred-basal-friction-and-mass-flux-affected-by-crystalorientation-fabrics(90373ceb-cf59-4fd1-b502-f82acc703157).html https://doi.org/10.1017/jog.2021.88 https://curis.ku.dk/ws/files/306674813/inferred_basal_friction_and_mass_flux_affected_by_crystal_orientation_fabrics.pdf |
id |
ftcopenhagenunip:oai:pure.atira.dk:publications/90373ceb-cf59-4fd1-b502-f82acc703157 |
---|---|
record_format |
openpolar |
spelling |
ftcopenhagenunip:oai:pure.atira.dk:publications/90373ceb-cf59-4fd1-b502-f82acc703157 2024-06-09T07:47:23+00:00 Inferred basal friction and mass flux affected by crystal-orientation fabrics Rathmann, Nicholas M. Lilien, David A. 2022 application/pdf https://curis.ku.dk/portal/da/publications/inferred-basal-friction-and-mass-flux-affected-by-crystalorientation-fabrics(90373ceb-cf59-4fd1-b502-f82acc703157).html https://doi.org/10.1017/jog.2021.88 https://curis.ku.dk/ws/files/306674813/inferred_basal_friction_and_mass_flux_affected_by_crystal_orientation_fabrics.pdf eng eng info:eu-repo/semantics/openAccess Rathmann , N M & Lilien , D A 2022 , ' Inferred basal friction and mass flux affected by crystal-orientation fabrics ' , Journal of Glaciology , vol. 68 , no. 268 , pp. 236-252 . https://doi.org/10.1017/jog.2021.88 Anisotropic ice flow ice rheology recrystallisation subglacial processes article 2022 ftcopenhagenunip https://doi.org/10.1017/jog.2021.88 2024-05-16T11:29:24Z We investigate the errors caused by neglecting the crystal-orientation fabric when inferring the basal friction coefficient field, and whether such errors can be alleviated by inferring an isotropic enhancement factor field to compensate for missing fabric information. We calculate the steady states that arise from ice flowing over a sticky spot and a bedrock bump using a vertical-slab numerical ice-flow model, consisting of a Weertman sliding law and the anisotropic Johnson flow law, coupled to a spectral fabric model of lattice rotation and dynamic recrystallisation. Given the steady or transient states as input for a canonical adjoint-based inversion, we find that Glen's isotropic flow law cannot necessarily be used to infer the true basal drag or friction coefficient field, which are obscured by the orientation fabric, thus potentially affecting vertically integrated mass fluxes. By inverting for an equivalent isotropic enhancement factor, a more accurate mass flux can be recovered, suggesting that joint inversions for basal friction and the isotropic flow-rate factor may be able to compensate for mechanical anisotropies caused by the fabric. Thus, in addition to other sources of rheological uncertainty, fabric might complicate attempts to relate subglacial conditions to basal properties inferred from an inversion relying on Glen's law. Article in Journal/Newspaper Journal of Glaciology University of Copenhagen: Research Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) Journal of Glaciology 68 268 236 252 |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
topic |
Anisotropic ice flow ice rheology recrystallisation subglacial processes |
spellingShingle |
Anisotropic ice flow ice rheology recrystallisation subglacial processes Rathmann, Nicholas M. Lilien, David A. Inferred basal friction and mass flux affected by crystal-orientation fabrics |
topic_facet |
Anisotropic ice flow ice rheology recrystallisation subglacial processes |
description |
We investigate the errors caused by neglecting the crystal-orientation fabric when inferring the basal friction coefficient field, and whether such errors can be alleviated by inferring an isotropic enhancement factor field to compensate for missing fabric information. We calculate the steady states that arise from ice flowing over a sticky spot and a bedrock bump using a vertical-slab numerical ice-flow model, consisting of a Weertman sliding law and the anisotropic Johnson flow law, coupled to a spectral fabric model of lattice rotation and dynamic recrystallisation. Given the steady or transient states as input for a canonical adjoint-based inversion, we find that Glen's isotropic flow law cannot necessarily be used to infer the true basal drag or friction coefficient field, which are obscured by the orientation fabric, thus potentially affecting vertically integrated mass fluxes. By inverting for an equivalent isotropic enhancement factor, a more accurate mass flux can be recovered, suggesting that joint inversions for basal friction and the isotropic flow-rate factor may be able to compensate for mechanical anisotropies caused by the fabric. Thus, in addition to other sources of rheological uncertainty, fabric might complicate attempts to relate subglacial conditions to basal properties inferred from an inversion relying on Glen's law. |
format |
Article in Journal/Newspaper |
author |
Rathmann, Nicholas M. Lilien, David A. |
author_facet |
Rathmann, Nicholas M. Lilien, David A. |
author_sort |
Rathmann, Nicholas M. |
title |
Inferred basal friction and mass flux affected by crystal-orientation fabrics |
title_short |
Inferred basal friction and mass flux affected by crystal-orientation fabrics |
title_full |
Inferred basal friction and mass flux affected by crystal-orientation fabrics |
title_fullStr |
Inferred basal friction and mass flux affected by crystal-orientation fabrics |
title_full_unstemmed |
Inferred basal friction and mass flux affected by crystal-orientation fabrics |
title_sort |
inferred basal friction and mass flux affected by crystal-orientation fabrics |
publishDate |
2022 |
url |
https://curis.ku.dk/portal/da/publications/inferred-basal-friction-and-mass-flux-affected-by-crystalorientation-fabrics(90373ceb-cf59-4fd1-b502-f82acc703157).html https://doi.org/10.1017/jog.2021.88 https://curis.ku.dk/ws/files/306674813/inferred_basal_friction_and_mass_flux_affected_by_crystal_orientation_fabrics.pdf |
long_lat |
ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
Weertman |
geographic_facet |
Weertman |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Rathmann , N M & Lilien , D A 2022 , ' Inferred basal friction and mass flux affected by crystal-orientation fabrics ' , Journal of Glaciology , vol. 68 , no. 268 , pp. 236-252 . https://doi.org/10.1017/jog.2021.88 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1017/jog.2021.88 |
container_title |
Journal of Glaciology |
container_volume |
68 |
container_issue |
268 |
container_start_page |
236 |
op_container_end_page |
252 |
_version_ |
1801378435072786432 |