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Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity

Marsh, O.J. and Rack, W. and Floricioiu, D. and Golledge, N.R. and Lawson, W. (2013) Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity. The Cryosphere, 7, pp. 1375-1384. Copernicus Publications. DOI: 10.5194/tc-7-1375-2013 ISSN 1994-0416

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Official URL: http://www.the-cryosphere.net/7/1375/2013/

Abstract

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.

Item URL in elib:https://elib.dlr.de/86623/
Document Type:Article
Title:Tidally induced velocity variations of the Beardmore Glacier, Antarctica, and their representation in satellite measurements of ice velocity
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Marsh, O.J.Gateway Antarctica, University of Canterbury, Christchurch, New ZealandUNSPECIFIED
Rack, W.Gateway Antarctica, University of Canterbury, Christchurch, New ZealandUNSPECIFIED
Floricioiu, D.German Aerospace Center (DLR), Oberpfaffenhofen, GermanyUNSPECIFIED
Golledge, N.R.Antarctic Research Centre, Victoria University of Wellington, Wellington, New ZealandUNSPECIFIED
Lawson, W.Department of Geography, University of Canterbury, Christchurch, New ZealandUNSPECIFIED
Date:10 September 2013
Journal or Publication Title:The Cryosphere
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:7
DOI :10.5194/tc-7-1375-2013
Page Range:pp. 1375-1384
Publisher:Copernicus Publications
Series Name:The Cryosphere
ISSN:1994-0416
Status:Published
Keywords:glacier velocity, tidal effect, TerraSAR-X
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Vorhaben hochauflösende Fernerkundungsverfahren
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > SAR Signal Processing
Deposited By: Floricioiu, Dr. Dana
Deposited On:12 Dec 2013 09:50
Last Modified:09 Jan 2019 12:23

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