A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica
We report on long-term surface elevation changes of the central Amery Ice Shelf (AIS) by comparing elevation records spanning 4 decades (19682007). We use elevation records acquired with the following methods: optical leveling (19681969); ERS radar altimetry (19922003); GPS (19952006); and Ice, Clou...
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Australian Geophysical Union
2009
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ftunivtasecite:oai:ecite.utas.edu.au:62241 2023-05-15T13:22:04+02:00 A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica King, MA Coleman, R Freemantle, A Fricker, HA Hurd, R Legresy, B Padman, L Warner, RC 2009 application/pdf http://www.agu.org/pubs/ https://doi.org/10.1029/2008JF001094 http://ecite.utas.edu.au/62241 en eng Australian Geophysical Union http://ecite.utas.edu.au/62241/1/King_etal_JGR(Earth)_2008JF001094.pdf http://dx.doi.org/10.1029/2008JF001094 King, MA and Coleman, R and Freemantle, A and Fricker, HA and Hurd, R and Legresy, B and Padman, L and Warner, RC, A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica, Journal of Geophysical Research Earth Surface, 114, (F1) Article F01010. ISSN 0148-0227 (2009) [Refereed Article] http://ecite.utas.edu.au/62241 Engineering Geomatic Engineering Geodesy Refereed Article PeerReviewed 2009 ftunivtasecite https://doi.org/10.1029/2008JF001094 2019-12-13T21:32:29Z We report on long-term surface elevation changes of the central Amery Ice Shelf (AIS) by comparing elevation records spanning 4 decades (19682007). We use elevation records acquired with the following methods: optical leveling (19681969); ERS radar altimetry (19922003); GPS (19952006); and Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry (20032007). We compute multidecadal elevation trend (dh/dt) values at crossovers between the leveling route and each of the GPS and ICESat tracks as well as shorter-period dh/dt at ERS-ERS, GPS-GPS, and ICESat-ICESat crossovers. At GPS-leveling crossovers the mean long-term dh/dt is −0.003 m a−1, and at ICESat-leveling crossovers the mean dh/dt is +0.013 m a−1; neither trend is significantly different from zero. The data do, however, exhibit variable trends: near-zero change between 1991 and mid-1996, then thickening to ∼2003, followed by thinning ∼20032007, with 5 year dh/dt averages exceeding ∼0.1 m a−1. The changes in dh/dt pattern in mid-1996 and again in 2003 occur with unexpected speed. The ice shelf exhibits different dh/dt patterns than does the surrounding grounded ice, suggesting that surface mass balance variations or longer-term variations in firn densification processes are unlikely to be major causes. We conclude that these observed multiyear elevation changes must be due to currently unexplained or presently poorly quantified phenomena involving surface or basal processes and/or ice dynamics. With the multidecadal stability of the AIS established, the short-term fluctuations that we observe suggests that for other ice shelves, observed strong dh/dt signals over short time periods do not necessarily indicate ice shelf instability. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctica Antarctica Journal East Antarctica Ice Shelf Ice Shelves eCite UTAS (University of Tasmania) Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) East Antarctica Journal of Geophysical Research 114 F1 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Engineering Geomatic Engineering Geodesy |
spellingShingle |
Engineering Geomatic Engineering Geodesy King, MA Coleman, R Freemantle, A Fricker, HA Hurd, R Legresy, B Padman, L Warner, RC A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
topic_facet |
Engineering Geomatic Engineering Geodesy |
description |
We report on long-term surface elevation changes of the central Amery Ice Shelf (AIS) by comparing elevation records spanning 4 decades (19682007). We use elevation records acquired with the following methods: optical leveling (19681969); ERS radar altimetry (19922003); GPS (19952006); and Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry (20032007). We compute multidecadal elevation trend (dh/dt) values at crossovers between the leveling route and each of the GPS and ICESat tracks as well as shorter-period dh/dt at ERS-ERS, GPS-GPS, and ICESat-ICESat crossovers. At GPS-leveling crossovers the mean long-term dh/dt is −0.003 m a−1, and at ICESat-leveling crossovers the mean dh/dt is +0.013 m a−1; neither trend is significantly different from zero. The data do, however, exhibit variable trends: near-zero change between 1991 and mid-1996, then thickening to ∼2003, followed by thinning ∼20032007, with 5 year dh/dt averages exceeding ∼0.1 m a−1. The changes in dh/dt pattern in mid-1996 and again in 2003 occur with unexpected speed. The ice shelf exhibits different dh/dt patterns than does the surrounding grounded ice, suggesting that surface mass balance variations or longer-term variations in firn densification processes are unlikely to be major causes. We conclude that these observed multiyear elevation changes must be due to currently unexplained or presently poorly quantified phenomena involving surface or basal processes and/or ice dynamics. With the multidecadal stability of the AIS established, the short-term fluctuations that we observe suggests that for other ice shelves, observed strong dh/dt signals over short time periods do not necessarily indicate ice shelf instability. |
format |
Article in Journal/Newspaper |
author |
King, MA Coleman, R Freemantle, A Fricker, HA Hurd, R Legresy, B Padman, L Warner, RC |
author_facet |
King, MA Coleman, R Freemantle, A Fricker, HA Hurd, R Legresy, B Padman, L Warner, RC |
author_sort |
King, MA |
title |
A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
title_short |
A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
title_full |
A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
title_fullStr |
A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
title_full_unstemmed |
A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica |
title_sort |
4-decade record of elevation change of the amery ice shelf, east antarctica |
publisher |
Australian Geophysical Union |
publishDate |
2009 |
url |
http://www.agu.org/pubs/ https://doi.org/10.1029/2008JF001094 http://ecite.utas.edu.au/62241 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) |
geographic |
Amery Amery Ice Shelf East Antarctica |
geographic_facet |
Amery Amery Ice Shelf East Antarctica |
genre |
Amery Ice Shelf Antarc* Antarctica Antarctica Journal East Antarctica Ice Shelf Ice Shelves |
genre_facet |
Amery Ice Shelf Antarc* Antarctica Antarctica Journal East Antarctica Ice Shelf Ice Shelves |
op_relation |
http://ecite.utas.edu.au/62241/1/King_etal_JGR(Earth)_2008JF001094.pdf http://dx.doi.org/10.1029/2008JF001094 King, MA and Coleman, R and Freemantle, A and Fricker, HA and Hurd, R and Legresy, B and Padman, L and Warner, RC, A 4-decade record of elevation change of the Amery Ice Shelf, East Antarctica, Journal of Geophysical Research Earth Surface, 114, (F1) Article F01010. ISSN 0148-0227 (2009) [Refereed Article] http://ecite.utas.edu.au/62241 |
op_doi |
https://doi.org/10.1029/2008JF001094 |
container_title |
Journal of Geophysical Research |
container_volume |
114 |
container_issue |
F1 |
_version_ |
1766363110725124096 |