d5b7e5a1-b04d-48d8-a440-c010658ec146 eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2020-11-03 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Radar characterization of ice crystal orientation fabric and anisotropic rheology within Rutford Ice Stream, 2017-2019 2020-11-03 creation 2020-11-03 revision 2020-11-03 publication 2020-11-03 released 1.0 https://doi.org/10.5285/d5b7e5a1-b04d-48d8-a440-c010658ec146 doi GB/NERC/BAS/PDC/01428 https://data.bas.ac.uk/ NE/G014159/1 award NE/G013187/1 award Please cite this item as: Jordan, T., Martin, C., Brisbourne, A., Schroeder, D., & Smith, A. (2020). Radar characterization of ice crystal orientation fabric and anisotropic rheology within Rutford Ice Stream, 2017-2019 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/d5b7e5a1-b04d-48d8-a440-c010658ec146 We use polarimetric radar sounding to investigate variation in ice crystal orientation fabric within the near-surface (top 40-300 m) of Rutford Ice Stream, West Antarctica. To assess the influence of the fabric on ice flow, we use an analytical model to derive anisotropic enhancements of the flow law from the fabric measurements. In the shallowest ice (40-100 m) the azimuthal fabric orientation is consistent with flow-induced development and correlates with the surface strain field. Notably, toward the ice-stream margins, both the horizontal compression angle and fabric orientation tend toward 45 degrees relative to ice flow. This result is consistent with theoretical predictions of flow-induced fabric under simple shear, but to our knowledge has never been observed. The fabric orientation in deeper ice (100-300 m) is significantly misaligned with shallower ice in some locations, and therefore inconsistent with the local surface strain field. This result represents a new challenge for ice flow models which typically infer basal properties from the surface conditions assuming simplified vertical variation of ice flow. Our technique retrieves azimuthal variations in fabric but is insensitive to vertical variation, and we therefore constrain the fabric and rheology within two end-members: a vertical girdle or a horizontal pole. Our hypotheses are that fabric near the center of the ice-stream tends to a vertical girdle that enhances horizontal compression, and near the ice-stream margins tends to a horizontal pole that enhances lateral shear. ApRES radar data were collected as part of the BEAMISH Project (NERC AFI award numbers NE/G014159/1 and NE/G013187/1). Tom Jordan would like to acknowledge support from EU Horizon 2020 grant 747336-BRISRES-H2020-MSCA-IF-2016. ***** PLEASE BE ADVISED THIS DATA SET HAS BEEN RETRACTED ***** This data set had incorrect coordinates for one of the sites. In addition, some files were incorrectly labelled as belonging to one of the sites A new data set (see 'Related Data Set Metadata' link below) addresses these issues and also includes significant additional data, as well as updated metadata and additional authors. Hence it is a wholly new data set, rather than an updated version of this data set. Please use this new data set instead. No credit. completed Jordan, Tom Univeristy of Bristol Researcher author Martin, Carlos British Antarctic Survey Researcher author Brisbourne, Alex British Antarctic Survey Researcher author Schroeder, Dustin Stanford University Researcher author Smith, Andrew British Antarctic Survey Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glacier Motion/Ice Sheet Motion EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets EARTH SCIENCE > Spectral/Engineering > Radar theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher anisotropy fabric ice flow polarimetry radar rheology theme Rutford Ice Stream Antarctica place Elevation theme GEMET - INSPIRE themes, version 1.0 2021-01-06 revision otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions This data is supplied under Open Government Licence v3.0 otherRestrictions No restrictions apply. doi doi crossReference doi doi crossReference url url crossReference doi doi crossReference url url largerWorkCitation url url crossReference doi doi crossReference textTable eng utf8 environment geoscientificInformation -83.92791 -83.58778 -78.13825 -78.1049 2017-01-20 2017-01-20 It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor application/x-hdf application/netcdf text/plain text/csv bytes 801950925 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=d5b7e5a1-b04d-48d8-a440-c010658ec146 WWW:LINK-1.0-http--link Get Data Download data download bytes 801950925 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=d5b7e5a1-b04d-48d8-a440-c010658ec146 WWW:LINK-1.0-http--link Get Data Download data download bytes 801950925 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=d5b7e5a1-b04d-48d8-a440-c010658ec146 WWW:LINK-1.0-http--link Get Data Download data download bytes 801950925 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=d5b7e5a1-b04d-48d8-a440-c010658ec146 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: Polarimetric data acquisition follows Brisbourne et al. 2019. This paper describes the quad-polarized measurement technique that was applied in the field. ApRES signal processing follows Brennan et al. 2014. This paper describes the processing steps applied to the raw data to generate ice-depth profiles for the phase and amplitude of radar wave. Polarimetric data processing follows Jordan et al. 2019. This paper describes the coherence methodology that is used to determine the quality of the radar data for fabric estimation. Data collection: Radar: ApRES (British Antarctic Survey's Autonomous phase-sensitive Radio-Echo Sounder) - chirps of 200 to 400 MHz in time intervals of 1 s. Data quality: Polarimetric data quality is established from the coherence magnitude, which provides a metric for sections of the ice column where fabric can be reliably estimated. Fabric estimates could be made in the top 100-200 m of the ice column at 18 of the 20 measurement sites (maximum depth ~ 100 m near the shear-margin, and ~200 m in the ice-stream centre). asNeeded completed