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The dynamics of the Amery Ice Shelf - Investigations using terrestrial and GPS data

Lookup NU author(s): Professor Matt King


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The Lambert Glacier-Amery Ice Shelf (AIS) system is a major feature of East Antarctica. Using a combination of terrestrial and GPS measurements, spanning a 30 year period, the dynamics of the AIS are studied. Continuous GPS data longer than one day and up to one month were processed using a segmentation technique for use in tidal studies. Significant north-south amplication is revealed in each of the major tidal constituents and comparisons were made with three existing numerical tide models. Estimates of the height of the water column beneath the ice shelf were made for a number of sites, based on the GPS-derived tidal constituents. The terrestrial ice shelf surveys of 1968-69 and 1969-70 were recomputed in a modern, tide-free ITRF coordinate frame with coordinate uncertainties (95\% confidence) of less than 5.2 m and velocity uncertainties of better than 3.6 myr$^{-1}$. More recent GPS data, collected from 1988 onwards, were processed season-by-season and combined using GAMIT/GLOBK. Final velocities were compared to an independent set derived from sequential Radarsat images. A congruency test on the in-situ velocities suggests that the AIS has been in steady state over the 1968-2000 time period. Strain rates were also determined using both terrestrial and GPS velocities, providing the best available in-situ data set for comparison with Radarsat imagery.

Publication metadata

Author(s): King M, Coleman R

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Eos Transactions of the AGU

Year of Conference: 2001

Pages: abstract IP41A-10

Publisher: American Geophysical Union