Ice-stream response to ocean tides and the form of the basal sliding law
The response of ice streams to ocean tides is investigated. Numerical modelling experiments are conducted using a two-dimensional flow-line model of coupled ice-stream and ice-shelf flow. The model includes all components of the equilibrium equations, and uses a non-linear viscoelastic constitutive...
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Copernicus Publications
2011
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ftdoajarticles:oai:doaj.org/article:22aa0f9bb5b34c6e80a07895a519279a 2023-05-15T13:41:00+02:00 Ice-stream response to ocean tides and the form of the basal sliding law G. H. Gudmundsson 2011-03-01T00:00:00Z https://doi.org/10.5194/tc-5-259-2011 https://doaj.org/article/22aa0f9bb5b34c6e80a07895a519279a EN eng Copernicus Publications http://www.the-cryosphere.net/5/259/2011/tc-5-259-2011.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-5-259-2011 1994-0416 1994-0424 https://doaj.org/article/22aa0f9bb5b34c6e80a07895a519279a The Cryosphere, Vol 5, Iss 1, Pp 259-270 (2011) Environmental sciences GE1-350 Geology QE1-996.5 article 2011 ftdoajarticles https://doi.org/10.5194/tc-5-259-2011 2022-12-31T15:03:32Z The response of ice streams to ocean tides is investigated. Numerical modelling experiments are conducted using a two-dimensional flow-line model of coupled ice-stream and ice-shelf flow. The model includes all components of the equilibrium equations, and uses a non-linear viscoelastic constitutive equation for ice. Basal sliding is simulated with a Weertman type sliding law where basal sliding is proportional to some power of the basal shear stress. The response of ice-streams to tidal forcing is found to be profoundly affected by mechanical conditions at the bed. For a non-linear sliding law, a non-linear interaction between the two main semi-diurnal tidal constituents (M2 and S2) can give rise to a significant perturbation in ice-stream flow at the lunisolar synodic fortnightly (MSf) tidal period of 14.76 days. For a linear sliding law, in contrast, no such modulation in flow at the MSf frequency is found. For vertical ocean tides of the type observed on Filchner-Ronne Ice Shelf (FRIS), the amplitude of the horizontal modulation in ice-stream flow at the MSf frequency resulting from a non-linear interaction between the S2 and M2 tidal constitutes can be larger than the direct response at the S2 and the M2 frequencies. In comparison the non-linear interaction between K1 and O1 tidal components is weak. As a consequence, modelled ice-stream response to mixed oceanic tides of the type found on FRIS is stronger at the MSf period of 14.76 days than at both the semi-diurnal and diurnal frequencies, while at the same time almost absent at the similar Mf period of 13.66 days. The model results compare favourably with measurements of tidally induced flow variations on Rutford Ice Stream (RIS), West Antarctica. On RIS a strong tidal response is found at the MSf frequency with a smaller response at the semi-diurnal and diurnal frequencies, and almost no response at the Mf frequency. A non-linear viscous sliding law appears to have the potential to fully explain these observations. Article in Journal/Newspaper Antarc* Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Rutford Ice Stream The Cryosphere West Antarctica Directory of Open Access Journals: DOAJ Articles West Antarctica Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Rutford ENVELOPE(-85.300,-85.300,-78.600,-78.600) Rutford Ice Stream ENVELOPE(-80.000,-80.000,-79.167,-79.167) Weertman ENVELOPE(-67.753,-67.753,-66.972,-66.972) The Cryosphere 5 1 259 270 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 G. H. Gudmundsson Ice-stream response to ocean tides and the form of the basal sliding law |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
The response of ice streams to ocean tides is investigated. Numerical modelling experiments are conducted using a two-dimensional flow-line model of coupled ice-stream and ice-shelf flow. The model includes all components of the equilibrium equations, and uses a non-linear viscoelastic constitutive equation for ice. Basal sliding is simulated with a Weertman type sliding law where basal sliding is proportional to some power of the basal shear stress. The response of ice-streams to tidal forcing is found to be profoundly affected by mechanical conditions at the bed. For a non-linear sliding law, a non-linear interaction between the two main semi-diurnal tidal constituents (M2 and S2) can give rise to a significant perturbation in ice-stream flow at the lunisolar synodic fortnightly (MSf) tidal period of 14.76 days. For a linear sliding law, in contrast, no such modulation in flow at the MSf frequency is found. For vertical ocean tides of the type observed on Filchner-Ronne Ice Shelf (FRIS), the amplitude of the horizontal modulation in ice-stream flow at the MSf frequency resulting from a non-linear interaction between the S2 and M2 tidal constitutes can be larger than the direct response at the S2 and the M2 frequencies. In comparison the non-linear interaction between K1 and O1 tidal components is weak. As a consequence, modelled ice-stream response to mixed oceanic tides of the type found on FRIS is stronger at the MSf period of 14.76 days than at both the semi-diurnal and diurnal frequencies, while at the same time almost absent at the similar Mf period of 13.66 days. The model results compare favourably with measurements of tidally induced flow variations on Rutford Ice Stream (RIS), West Antarctica. On RIS a strong tidal response is found at the MSf frequency with a smaller response at the semi-diurnal and diurnal frequencies, and almost no response at the Mf frequency. A non-linear viscous sliding law appears to have the potential to fully explain these observations. |
format |
Article in Journal/Newspaper |
author |
G. H. Gudmundsson |
author_facet |
G. H. Gudmundsson |
author_sort |
G. H. Gudmundsson |
title |
Ice-stream response to ocean tides and the form of the basal sliding law |
title_short |
Ice-stream response to ocean tides and the form of the basal sliding law |
title_full |
Ice-stream response to ocean tides and the form of the basal sliding law |
title_fullStr |
Ice-stream response to ocean tides and the form of the basal sliding law |
title_full_unstemmed |
Ice-stream response to ocean tides and the form of the basal sliding law |
title_sort |
ice-stream response to ocean tides and the form of the basal sliding law |
publisher |
Copernicus Publications |
publishDate |
2011 |
url |
https://doi.org/10.5194/tc-5-259-2011 https://doaj.org/article/22aa0f9bb5b34c6e80a07895a519279a |
long_lat |
ENVELOPE(-61.000,-61.000,-78.500,-78.500) ENVELOPE(-85.300,-85.300,-78.600,-78.600) ENVELOPE(-80.000,-80.000,-79.167,-79.167) ENVELOPE(-67.753,-67.753,-66.972,-66.972) |
geographic |
West Antarctica Ronne Ice Shelf Rutford Rutford Ice Stream Weertman |
geographic_facet |
West Antarctica Ronne Ice Shelf Rutford Rutford Ice Stream Weertman |
genre |
Antarc* Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Rutford Ice Stream The Cryosphere West Antarctica |
genre_facet |
Antarc* Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ronne Ice Shelf Rutford Ice Stream The Cryosphere West Antarctica |
op_source |
The Cryosphere, Vol 5, Iss 1, Pp 259-270 (2011) |
op_relation |
http://www.the-cryosphere.net/5/259/2011/tc-5-259-2011.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-5-259-2011 1994-0416 1994-0424 https://doaj.org/article/22aa0f9bb5b34c6e80a07895a519279a |
op_doi |
https://doi.org/10.5194/tc-5-259-2011 |
container_title |
The Cryosphere |
container_volume |
5 |
container_issue |
1 |
container_start_page |
259 |
op_container_end_page |
270 |
_version_ |
1766144223845810176 |