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Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999


King, MA and Coleman, R and Morgan, PJ and Hurd, R, Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999, Journal of Geophysical Research Earth Surface, 112, (F1) pp. F01013. ISSN 0148-0227 (2007) [Refereed Article]

DOI: doi:10.1029/2006JF000609


Historic velocity measurements of Antarctica's ice sheet represent vital baseline values that allow ice flow velocity variations to be observed over multidecadal timescales, such as those due to climate change. Using velocity values derived from geodetic quality measurements made in the 1960s and from more recent GPS and remote sensing studies during the 1990s, we examine the variability of ice flow velocities of the northern Amery Ice Shelf, East Antarctica, over the 30-year period, 1968-1999. The historic ice shelf velocities are reexamined using original field notes and the previous data analyses are shown to be erroneous, yielding positional and velocity errors of up to 4 km and 150 m/yr respectively. Once corrected, these historic measurements are shown to be in close (1-5 m/yr) general agreement with GPS-derived velocities from the 1990s at similar geographical locations, providing one of the first precise constraints on multidecadal ice shelf velocity variations on a large Antarctic ice shelf. Comparison of the terrestrial and GPS velocities with spatially dense velocity measurements from remote sensing imagery reveals a systematic bias in the latter of up to ±30 m/yr, mostly due to propagation of unmodeled vertical ice shelf motion due to tides and atmospheric pressure variations. We therefore excluded the remote sensing velocities from further comparison and suggest caution in the interpretation of similarly derived ice shelf velocities. Velocity differences between the GPS and terrestrial surveys were compared at nine geographical locations suggesting a small (∼2.2 m/yr or ∼0.6%), but statistically significant, slowdown of the ice shelf. Copyright 2007 by the American Geophysical Union.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geodesy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Coleman, R (Professor Richard Coleman)
UTAS Author:Hurd, R (Dr Rachael Hurd)
ID Code:44115
Year Published:2007
Web of Science® Times Cited:18
Deposited By:Geography and Environmental Studies
Deposited On:2007-08-01
Last Modified:2011-11-07

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