Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity
Ocean tides close to the grounding line of outlet glaciers around Antarctica have been shown to directly influence ice velocity, both linearly and non-linearly. These fluctuations can be significant and have the potential to affect satellite measurements of ice discharge, which assume displacement b...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:3c755d2fb513400cbe04cf992639b818 2023-05-15T13:39:34+02:00 Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity O. J. Marsh W. Rack D. Floricioiu N. R. Golledge W. Lawson 2013-09-01 https://doi.org/10.5194/tc-7-1375-2013 http://www.the-cryosphere.net/7/1375/2013/tc-7-1375-2013.pdf https://doaj.org/article/3c755d2fb513400cbe04cf992639b818 en eng Copernicus Publications doi:10.5194/tc-7-1375-2013 1994-0416 1994-0424 http://www.the-cryosphere.net/7/1375/2013/tc-7-1375-2013.pdf https://doaj.org/article/3c755d2fb513400cbe04cf992639b818 undefined The Cryosphere, Vol 7, Iss 5, Pp 1375-1384 (2013) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2013 fttriple https://doi.org/10.5194/tc-7-1375-2013 2023-01-22T18:19:31Z Ocean tides close to the grounding line of outlet glaciers around Antarctica have been shown to directly influence ice velocity, both linearly and non-linearly. These fluctuations can be significant and have the potential to affect satellite measurements of ice discharge, which assume displacement between satellite passes to be consistent and representative of annual means. Satellite observations of horizontal velocity variation in the grounding zone are also contaminated by vertical tidal effects, the importance of which is highlighted here in speckle tracking measurements. Eight TerraSAR-X scenes from the grounding zone of the Beardmore Glacier are analysed in conjunction with GPS measurements to determine short-term and decadal trends in ice velocity. Diurnal tides produce horizontal velocity fluctuations of >50% on the ice shelf, recorded in the GPS data 4 km downstream of the grounding line. This variability decreases rapidly to <5% only 15 km upstream of the grounding line. Daily fluctuations are smoothed to <1% in the 11-day repeat pass TerraSAR-X imagery, but fortnightly variations over this period are still visible and show that satellite-velocity measurements can be affected by tides over longer periods. The measured tidal displacement observed in radar look direction over floating ice also allows the grounding line to be identified, using differential speckle tracking where phase information cannot be easily unwrapped. Article in Journal/Newspaper Antarc* Antarctica Beardmore Glacier Ice Shelf The Cryosphere Unknown Beardmore ENVELOPE(174.900,174.900,-83.350,-83.350) Beardmore Glacier ENVELOPE(170.000,170.000,-84.500,-84.500) The Cryosphere 7 5 1375 1384 |
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English |
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geo envir O. J. Marsh W. Rack D. Floricioiu N. R. Golledge W. Lawson Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
topic_facet |
geo envir |
description |
Ocean tides close to the grounding line of outlet glaciers around Antarctica have been shown to directly influence ice velocity, both linearly and non-linearly. These fluctuations can be significant and have the potential to affect satellite measurements of ice discharge, which assume displacement between satellite passes to be consistent and representative of annual means. Satellite observations of horizontal velocity variation in the grounding zone are also contaminated by vertical tidal effects, the importance of which is highlighted here in speckle tracking measurements. Eight TerraSAR-X scenes from the grounding zone of the Beardmore Glacier are analysed in conjunction with GPS measurements to determine short-term and decadal trends in ice velocity. Diurnal tides produce horizontal velocity fluctuations of >50% on the ice shelf, recorded in the GPS data 4 km downstream of the grounding line. This variability decreases rapidly to <5% only 15 km upstream of the grounding line. Daily fluctuations are smoothed to <1% in the 11-day repeat pass TerraSAR-X imagery, but fortnightly variations over this period are still visible and show that satellite-velocity measurements can be affected by tides over longer periods. The measured tidal displacement observed in radar look direction over floating ice also allows the grounding line to be identified, using differential speckle tracking where phase information cannot be easily unwrapped. |
format |
Article in Journal/Newspaper |
author |
O. J. Marsh W. Rack D. Floricioiu N. R. Golledge W. Lawson |
author_facet |
O. J. Marsh W. Rack D. Floricioiu N. R. Golledge W. Lawson |
author_sort |
O. J. Marsh |
title |
Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
title_short |
Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
title_full |
Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
title_fullStr |
Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
title_full_unstemmed |
Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity |
title_sort |
tidally induced velocity variations of the beardmore glacier, antarctica, and their representation in satellite measurements of ice velocity |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/tc-7-1375-2013 http://www.the-cryosphere.net/7/1375/2013/tc-7-1375-2013.pdf https://doaj.org/article/3c755d2fb513400cbe04cf992639b818 |
long_lat |
ENVELOPE(174.900,174.900,-83.350,-83.350) ENVELOPE(170.000,170.000,-84.500,-84.500) |
geographic |
Beardmore Beardmore Glacier |
geographic_facet |
Beardmore Beardmore Glacier |
genre |
Antarc* Antarctica Beardmore Glacier Ice Shelf The Cryosphere |
genre_facet |
Antarc* Antarctica Beardmore Glacier Ice Shelf The Cryosphere |
op_source |
The Cryosphere, Vol 7, Iss 5, Pp 1375-1384 (2013) |
op_relation |
doi:10.5194/tc-7-1375-2013 1994-0416 1994-0424 http://www.the-cryosphere.net/7/1375/2013/tc-7-1375-2013.pdf https://doaj.org/article/3c755d2fb513400cbe04cf992639b818 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-7-1375-2013 |
container_title |
The Cryosphere |
container_volume |
7 |
container_issue |
5 |
container_start_page |
1375 |
op_container_end_page |
1384 |
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1766120415651954688 |