On the limit to resolution and information on basal properties obtainable from surface data on ice streams
International audience 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...
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ftccsdartic:oai:HAL:hal-00298550v1 2023-11-12T04:27:17+01:00 On the limit to resolution and information on basal properties obtainable from surface data on ice streams Gudmundsson, G. H. Raymond, M. British Antarctic Survey (BAS) Natural Environment Research Council (NERC) Section of Glaciology 2008-06-11 https://hal.science/hal-00298550 https://hal.science/hal-00298550/document https://hal.science/hal-00298550/file/tcd-2-413-2008.pdf en eng HAL CCSD Copernicus hal-00298550 https://hal.science/hal-00298550 https://hal.science/hal-00298550/document https://hal.science/hal-00298550/file/tcd-2-413-2008.pdf info:eu-repo/semantics/OpenAccess ISSN: 1994-0432 EISSN: 1994-0440 The Cryosphere Discussions https://hal.science/hal-00298550 The Cryosphere Discussions, 2008, 2 (3), pp.413-445 [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2008 ftccsdartic 2023-10-21T23:15:03Z International audience 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. The methods requires no smoothing of surface data. Our main focus here is on how errors and spacing of surface data affects 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. Retrieval of basal slipperiness is found to be highly sensitive to unmodelled errors in basal topography. Article in Journal/Newspaper The Cryosphere The Cryosphere Discussions Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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Open Polar |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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ftccsdartic |
language |
English |
topic |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Gudmundsson, G. H. Raymond, M. On the limit to resolution and information on basal properties obtainable from surface data on ice streams |
topic_facet |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience 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. The methods requires no smoothing of surface data. Our main focus here is on how errors and spacing of surface data affects 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. Retrieval of basal slipperiness is found to be highly sensitive to unmodelled errors in basal topography. |
author2 |
British Antarctic Survey (BAS) Natural Environment Research Council (NERC) Section of Glaciology |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, G. H. Raymond, M. |
author_facet |
Gudmundsson, G. H. Raymond, M. |
author_sort |
Gudmundsson, G. H. |
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 |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.science/hal-00298550 https://hal.science/hal-00298550/document https://hal.science/hal-00298550/file/tcd-2-413-2008.pdf |
genre |
The Cryosphere The Cryosphere Discussions |
genre_facet |
The Cryosphere The Cryosphere Discussions |
op_source |
ISSN: 1994-0432 EISSN: 1994-0440 The Cryosphere Discussions https://hal.science/hal-00298550 The Cryosphere Discussions, 2008, 2 (3), pp.413-445 |
op_relation |
hal-00298550 https://hal.science/hal-00298550 https://hal.science/hal-00298550/document https://hal.science/hal-00298550/file/tcd-2-413-2008.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782340940323618816 |