On the limit to resolution and information on basal properties obtainable from surface data on ice streams
An optimal estimation method for simultaneously determining both basal slipperiness and basal topography from variations in surface flow velocity and topography along a flow line on ice streams and ice sheets is presented. We use Bayesian inference to update prior statistical estimates for basal top...
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Language: | English |
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2008
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/37984/ https://doi.org/10.5194/tc-2-167-2008 https://nrl.northumbria.ac.uk/id/eprint/37984/1/tc-2-167-2008.pdf |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:37984 2023-05-15T18:32:28+02:00 On the limit to resolution and information on basal properties obtainable from surface data on ice streams Gudmundsson, Hilmar Raymond, M. 2008-12-05 text https://nrl.northumbria.ac.uk/id/eprint/37984/ https://doi.org/10.5194/tc-2-167-2008 https://nrl.northumbria.ac.uk/id/eprint/37984/1/tc-2-167-2008.pdf en eng Coperincus https://nrl.northumbria.ac.uk/id/eprint/37984/1/tc-2-167-2008.pdf Gudmundsson, Hilmar and Raymond, M. (2008) On the limit to resolution and information on basal properties obtainable from surface data on ice streams. The Cryosphere, 2. pp. 167-178. ISSN 1994-0424 cc_by_4_0 CC-BY F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2008 ftunivnorthumb https://doi.org/10.5194/tc-2-167-2008 2022-09-25T06:09:12Z An optimal estimation method for simultaneously determining both basal slipperiness and basal topography from variations in surface flow velocity and topography along a flow line on ice streams and ice sheets is presented. We use Bayesian inference to update prior statistical estimates for basal topography and slipperiness using surface measurements along a flow line. Our main focus here is on how errors and spacing of surface data affect estimates of basal quantities and on possibly aliasing/mixing between basal slipperiness and basal topography. We find that the effects of spatial variations in basal topography and basal slipperiness on surface data can be accurately separated from each other, and mixing in retrieval does not pose a serious problem. For realistic surface data errors and density, small-amplitude perturbations in basal slipperiness can only be resolved for wavelengths larger than about 50 times the mean ice thickness. Bedrock topography is well resolved down to horizontal scale equal to about one ice thickness. Estimates of basal slipperiness are not significantly improved by accurate prior estimates of basal topography. However, retrieval of basal slipperiness is found to be highly sensitive to unmodelled errors in basal topography. Article in Journal/Newspaper The Cryosphere Northumbria University, Newcastle: Northumbria Research Link (NRL) The Cryosphere 2 2 167 178 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Gudmundsson, Hilmar Raymond, M. On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
An optimal estimation method for simultaneously determining both basal slipperiness and basal topography from variations in surface flow velocity and topography along a flow line on ice streams and ice sheets is presented. We use Bayesian inference to update prior statistical estimates for basal topography and slipperiness using surface measurements along a flow line. Our main focus here is on how errors and spacing of surface data affect estimates of basal quantities and on possibly aliasing/mixing between basal slipperiness and basal topography. We find that the effects of spatial variations in basal topography and basal slipperiness on surface data can be accurately separated from each other, and mixing in retrieval does not pose a serious problem. For realistic surface data errors and density, small-amplitude perturbations in basal slipperiness can only be resolved for wavelengths larger than about 50 times the mean ice thickness. Bedrock topography is well resolved down to horizontal scale equal to about one ice thickness. Estimates of basal slipperiness are not significantly improved by accurate prior estimates of basal topography. However, retrieval of basal slipperiness is found to be highly sensitive to unmodelled errors in basal topography. |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, Hilmar Raymond, M. |
author_facet |
Gudmundsson, Hilmar Raymond, M. |
author_sort |
Gudmundsson, Hilmar |
title |
On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
title_short |
On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
title_full |
On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
title_fullStr |
On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
title_full_unstemmed |
On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
title_sort |
on the limit to resolution and information on basal properties obtainable from surface data on ice streams |
publisher |
Coperincus |
publishDate |
2008 |
url |
https://nrl.northumbria.ac.uk/id/eprint/37984/ https://doi.org/10.5194/tc-2-167-2008 https://nrl.northumbria.ac.uk/id/eprint/37984/1/tc-2-167-2008.pdf |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/37984/1/tc-2-167-2008.pdf Gudmundsson, Hilmar and Raymond, M. (2008) On the limit to resolution and information on basal properties obtainable from surface data on ice streams. The Cryosphere, 2. pp. 167-178. ISSN 1994-0424 |
op_rights |
cc_by_4_0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-2-167-2008 |
container_title |
The Cryosphere |
container_volume |
2 |
container_issue |
2 |
container_start_page |
167 |
op_container_end_page |
178 |
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1766216578820472832 |