Data

Amery Ice Shelf velocity time series from Landsat images

Australian Antarctic Division
Young, N.W. ; YOUNG, NEAL W
Viewed: [[ro.stat.viewed]] Cited: [[ro.stat.cited]] Accessed: [[ro.stat.accessed]]
ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=info:doi10.4225/15/595ad4757f0f6&rft.title=Amery Ice Shelf velocity time series from Landsat images&rft.identifier=10.4225/15/595ad4757f0f6&rft.publisher=Australian Antarctic Data Centre&rft.description=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 prior 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).Progress Code: completedStatement: 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).&rft.creator=Young, N.W. &rft.creator=YOUNG, NEAL W &rft.date=2008&rft.coverage=westlimit=62; southlimit=-75; eastlimit=70; northlimit=-73&rft.coverage=westlimit=62; southlimit=-75; eastlimit=70; northlimit=-73&rft_rights=These data are publicly available for download from the provided URL.&rft_rights=Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/legalcode&rft_rights=This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAD_Ant_AIS_vel_series when using these data.&rft_rights=This metadata record is publicly available.&rft_subject=environment&rft_subject=geoscientificInformation&rft_subject=EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS&rft_subject=EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS > GLACIER MOTION/ICE SHEET MOTION&rft_subject=Amery Ice Shelf&rft_subject=Lambert Glacier&rft_subject=Ice Velocity&rft_subject=Landsat 7&rft_subject=ETM+ > Enhanced Thematic Mapper Plus&rft_subject=TM > Thematic Mapper&rft_subject=LANDSAT&rft_subject=LANDSAT-7&rft_subject=SATELLITES&rft_subject=AMD/AU&rft_subject=CEOS&rft_subject=AMD&rft_subject=ACE/CRC&rft_subject=CONTINENT > ANTARCTICA&rft_subject=GEOGRAPHIC REGION > POLAR&rft.type=dataset&rft.language=English Access the data
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Attribution 4.0 International (CC BY 4.0)
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These data are publicly available for download from the provided URL.

This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAD_Ant_AIS_vel_series when using these data.

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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 prior 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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Progress Code: completed
Statement: 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).

Data time period: 1999-01-01 to 2006-12-31

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70,-73 70,-75 62,-75 62,-73 70,-73

66,-74

text: westlimit=62; southlimit=-75; eastlimit=70; northlimit=-73

Subjects
ACE/CRC | AMD | AMD/AU | Amery Ice Shelf | CEOS | CONTINENT > ANTARCTICA | EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS | EARTH SCIENCE > CRYOSPHERE > GLACIERS/ICE SHEETS > GLACIER MOTION/ICE SHEET MOTION | ETM+ > Enhanced Thematic Mapper Plus | GEOGRAPHIC REGION > POLAR | Ice Velocity | LANDSAT | LANDSAT-7 | Lambert Glacier | Landsat 7 | SATELLITES | TM > Thematic Mapper | environment | geoscientificInformation |

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Other Information
Download point for the data (GET DATA > DIRECT DOWNLOAD)

url : https://data.aad.gov.au/eds/1589/download

Public information for ASAC project 3067 (PROJECT HOME PAGE)

url : https://projects.aad.gov.au/search_projects_results.cfm?project_no=3067

Citation reference for this metadata record and dataset (VIEW RELATED INFORMATION)

url : http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAD_Ant_AIS_vel_series

Identifiers
ACN 633 798 857