[Keyword='Amery Ice Shelf']
Amery Ice Shelf velocity time series from Landsat imagesEntry ID: AAD_Ant_AIS_vel_series
Abstract: A time series of ice velocity values have been derived by analysis of LandSat-7 ETM+ images for the Lambert Glacier and Amery Ice Shelf system.
The analysis technique uses feature tracking in pairs of Landsat-7 ETM+ images. This process uses surface features that persist with time and move with the ice as tracers of the ice motion. The displacement of these features over the time interval ... between acquisition of the two images in a pair is determined by image correlation. The analysis is made at regular increments across and along the images, to produce a regular grid of values. The derived values are filtered and validated according to set of a priori constraints for the flow in a local region and the statistics of a set of velocity values within a window. The images have been projected onto a common reference system, and spliced together in order to produce a seamless set of velocity values.
Horizontal components of strain rate are derived from the velocity data using a set of derivative operators in a least-squares solution of an over-constrained set of equations, which uses all velocity values within a computation window. This procedure effectively produces a set of average velocity and strain rate values and accounts for much of the noise in the individual velocity observations. Values of the local longitudinal, transverse and shear strain rate components are derived by rotation of the cartesian values to the local flow direction. The procedure is described in Young and Hyland (2002).
This metadata record has been derived from work performed under the auspices of ASAC project 3067 (ASAC_3067).
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Data Set Citation
Dataset Originator/Creator: Neal Young
Dataset Release Date: 2010-07-21
Start Date: 1999-01-01Stop Date: 2006-12-31
Latitude Resolution: 0.025 km
Longitude Resolution: 0.025 km
Quality Position coordinates are accurate to better than +/- 50 m from nominal location accuracy of the satellite image products and be validation against Ground Control Points
Velocity components have an accuracy which varies between data sets. It is dependent on the accuracy of the feature displacement (typically +/- 8 m), registration accuracy of an image pair (typically around 20 m), and the time increment between image acquisitions (typically one or more years).
Access Constraints New data
Access restricted until 21-July-2010
Requests to be made to Investigator
Use Constraints This data set conforms to the PICCCBY Attribution License
Please follow instructions listed in the citation reference provided at the URL below when using these data.
Data Set Progress
Distribution Media: HTTP
Distribution Size: 20 kb
Distribution Format: NetCDF files
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 3 6226 2955
Email: Neal.Young at aad.gov.au
ACE CRC AND AUSTRALIAN ANTARCTIC DIVISION Private Bag 80
Province or State: Tasmania
Postal Code: 7001
Creation and Review Dates
DIF Creation Date: 2008-07-20
Last DIF Revision Date: 2009-07-20