Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999
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 a...
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ftunivtasecite:oai:ecite.utas.edu.au:81943 2023-05-15T13:22:04+02:00 Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 King, MA Coleman, R Morgan, PJ Hurd, RS 2007 https://doi.org/10.1029/2006JF000609 http://ecite.utas.edu.au/81943 en eng x http://dx.doi.org/10.1029/2006JF000609 King, MA and Coleman, R and Morgan, PJ and Hurd, RS, Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999, Journal of Geophysical Research: Earth Surface, 112, (F1) ISSN 0148-0227 (2007) [Refereed Article] http://ecite.utas.edu.au/81943 Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified Refereed Article PeerReviewed 2007 ftunivtasecite https://doi.org/10.1029/2006JF000609 2019-12-13T21:46:56Z 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. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf eCite UTAS (University of Tasmania) Antarctic East Antarctica Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Journal of Geophysical Research 112 F1 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified |
spellingShingle |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified King, MA Coleman, R Morgan, PJ Hurd, RS Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
topic_facet |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified |
description |
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. |
format |
Article in Journal/Newspaper |
author |
King, MA Coleman, R Morgan, PJ Hurd, RS |
author_facet |
King, MA Coleman, R Morgan, PJ Hurd, RS |
author_sort |
King, MA |
title |
Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
title_short |
Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
title_full |
Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
title_fullStr |
Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
title_full_unstemmed |
Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999 |
title_sort |
velocity change of the amery ice shelf, east antarctica, during the period 1968-1999 |
publisher |
x |
publishDate |
2007 |
url |
https://doi.org/10.1029/2006JF000609 http://ecite.utas.edu.au/81943 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) |
geographic |
Antarctic East Antarctica Amery Amery Ice Shelf |
geographic_facet |
Antarctic East Antarctica Amery Amery Ice Shelf |
genre |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Antarctica East Antarctica Ice Sheet Ice Shelf |
op_relation |
http://dx.doi.org/10.1029/2006JF000609 King, MA and Coleman, R and Morgan, PJ and Hurd, RS, Velocity change of the Amery Ice Shelf, East Antarctica, during the period 1968-1999, Journal of Geophysical Research: Earth Surface, 112, (F1) ISSN 0148-0227 (2007) [Refereed Article] http://ecite.utas.edu.au/81943 |
op_doi |
https://doi.org/10.1029/2006JF000609 |
container_title |
Journal of Geophysical Research |
container_volume |
112 |
container_issue |
F1 |
_version_ |
1766363159913824256 |