Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier
There is significant uncertainty over how ice sheets and glaciers will respond to rising global temperatures. Limited knowledge of the topography and rheology of the ice–bed interface is a key cause of this uncertainty as models show that small changes in the bed can have a large influence on predic...
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Copernicus Publications
2022
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ftdoajarticles:oai:doaj.org/article:6c4a8daecebf421e9989be709f1e133d 2023-05-15T13:49:30+02:00 Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier H. Ockenden R. G. Bingham A. Curtis D. Goldberg 2022-09-01T00:00:00Z https://doi.org/10.5194/tc-16-3867-2022 https://doaj.org/article/6c4a8daecebf421e9989be709f1e133d EN eng Copernicus Publications https://tc.copernicus.org/articles/16/3867/2022/tc-16-3867-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-3867-2022 1994-0416 1994-0424 https://doaj.org/article/6c4a8daecebf421e9989be709f1e133d The Cryosphere, Vol 16, Pp 3867-3887 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-3867-2022 2022-12-30T21:05:40Z There is significant uncertainty over how ice sheets and glaciers will respond to rising global temperatures. Limited knowledge of the topography and rheology of the ice–bed interface is a key cause of this uncertainty as models show that small changes in the bed can have a large influence on predicted rates of ice loss. Most of our detailed knowledge of bed topography comes from airborne and ground-penetrating radar observations. However, these direct observations are not spaced closely enough to meet the requirements of ice-sheet models, so interpolation and inversion methods are used to fill in the gaps. Here we present the results of a new inversion of surface elevation and velocity data over Thwaites Glacier, West Antarctica, for bed topography and slipperiness (i.e. the degree of basal slip for a given level of drag). The inversion is based on a steady-state linear perturbation analysis of the shallow-ice-stream equations. The method works by identifying disturbances to surface flow which are caused by obstacles or sticky patches in the bed and can therefore be applied wherever the shallow-ice-stream equations hold and where surface data are available, even where the ice thickness is not well known. We assess the performance of the inversion for topography with the available radar data. Although the topographic output from the inversion is less successful where the bed slopes steeply, it compares well with radar data from the central trunk of the glacier for medium-wavelength features (5–50 km ). This method could therefore be useful as an independent test of other interpolation methods such as mass conservation and kriging. We do not have data to allow us to assess the success of the slipperiness results from our inversions, but we provide maps that may guide future seismic data collection across Thwaites Glacier. The methods presented here show significant promise for using high-resolution satellite datasets, calibrated by sparser field datasets, to generate high-resolution bed topography products across ... Article in Journal/Newspaper Antarc* Antarctica Ice Sheet The Cryosphere Thwaites Glacier West Antarctica Directory of Open Access Journals: DOAJ Articles West Antarctica Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) The Cryosphere 16 9 3867 3887 |
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 H. Ockenden R. G. Bingham A. Curtis D. Goldberg Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
There is significant uncertainty over how ice sheets and glaciers will respond to rising global temperatures. Limited knowledge of the topography and rheology of the ice–bed interface is a key cause of this uncertainty as models show that small changes in the bed can have a large influence on predicted rates of ice loss. Most of our detailed knowledge of bed topography comes from airborne and ground-penetrating radar observations. However, these direct observations are not spaced closely enough to meet the requirements of ice-sheet models, so interpolation and inversion methods are used to fill in the gaps. Here we present the results of a new inversion of surface elevation and velocity data over Thwaites Glacier, West Antarctica, for bed topography and slipperiness (i.e. the degree of basal slip for a given level of drag). The inversion is based on a steady-state linear perturbation analysis of the shallow-ice-stream equations. The method works by identifying disturbances to surface flow which are caused by obstacles or sticky patches in the bed and can therefore be applied wherever the shallow-ice-stream equations hold and where surface data are available, even where the ice thickness is not well known. We assess the performance of the inversion for topography with the available radar data. Although the topographic output from the inversion is less successful where the bed slopes steeply, it compares well with radar data from the central trunk of the glacier for medium-wavelength features (5–50 km ). This method could therefore be useful as an independent test of other interpolation methods such as mass conservation and kriging. We do not have data to allow us to assess the success of the slipperiness results from our inversions, but we provide maps that may guide future seismic data collection across Thwaites Glacier. The methods presented here show significant promise for using high-resolution satellite datasets, calibrated by sparser field datasets, to generate high-resolution bed topography products across ... |
format |
Article in Journal/Newspaper |
author |
H. Ockenden R. G. Bingham A. Curtis D. Goldberg |
author_facet |
H. Ockenden R. G. Bingham A. Curtis D. Goldberg |
author_sort |
H. Ockenden |
title |
Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
title_short |
Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
title_full |
Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
title_fullStr |
Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
title_full_unstemmed |
Inverting ice surface elevation and velocity for bed topography and slipperiness beneath Thwaites Glacier |
title_sort |
inverting ice surface elevation and velocity for bed topography and slipperiness beneath thwaites glacier |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-3867-2022 https://doaj.org/article/6c4a8daecebf421e9989be709f1e133d |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
West Antarctica Thwaites Glacier |
geographic_facet |
West Antarctica Thwaites Glacier |
genre |
Antarc* Antarctica Ice Sheet The Cryosphere Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctica Ice Sheet The Cryosphere Thwaites Glacier West Antarctica |
op_source |
The Cryosphere, Vol 16, Pp 3867-3887 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/3867/2022/tc-16-3867-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-3867-2022 1994-0416 1994-0424 https://doaj.org/article/6c4a8daecebf421e9989be709f1e133d |
op_doi |
https://doi.org/10.5194/tc-16-3867-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
9 |
container_start_page |
3867 |
op_container_end_page |
3887 |
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1766251447283875840 |