DOI: 10.5194/tc-7-1375-2013
Scopus记录号: 2-s2.0-84884611932
论文题名: Tidally induced velocity variations of the beardmore glacier, Antarctica, and their representation in satellite measurements of ice velocity
作者: Marsh O ; J ; , Rack W ; , Floricioiu D ; , Golledge N ; R ; , Lawson W
刊名: Cryosphere
ISSN: 19940416
出版年: 2013
卷: 7, 期: 5 起始页码: 1375
结束页码: 1384
语种: 英语
英文关键词: glacial environment
; GPS
; identification method
; measurement method
; nonlinearity
; satellite data
; satellite imagery
; TerraSAR-X
; tidal cycle
; velocity
; Antarctica
英文摘要: 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. © Author(s) 2013. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/74947
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Gateway Antarctica, University of Canterbury, Private Bag 4800, Christchurch, New Zealand; German Aerospace Centre (DLR), Oberpfaffenhofen, 82234 Weßling, Germany; Antarctic Research Centre, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand; GNS Science, Avalon, Lower Hutt 5011, New Zealand; Department of Geography, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Recommended Citation:
Marsh O,J,, Rack W,et al. Tidally induced velocity variations of the beardmore glacier, Antarctica, and their representation in satellite measurements of ice velocity[J]. Cryosphere,2013-01-01,7(5)