c560ce43-7aa0-4474-90ed-d4ee5f5768ea 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 2025-10-31 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 Acoustic impedance misfits and basal sliding law probabilities for Pine Island Glacier 2025-10-31 creation 2025-10-31 revision 2025-10-31 publication 2025-10-31 released 1.0 https://doi.org/10.5285/c560ce43-7aa0-4474-90ed-d4ee5f5768ea doi GB/NERC/BAS/PDC/02099 https://data.bas.ac.uk/ NE/S006672/1 award Please cite this item as: Hank, K., Arthern, R., & Williams, C. (2025). Acoustic impedance misfits and basal sliding law probabilities for Pine Island Glacier (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/c560ce43-7aa0-4474-90ed-d4ee5f5768ea This dataset contains acoustic impedance misfits between measurements collected on Pine Island Glacier (Brisbourne et al., 2017) and predictions of the Viscous Grain-Shearing theory (Buckingham, 1997, 2000, 2005, 2007). The dataset is presented as netCDF files. The acoustic impedance predictions depend on the effective pressure, which is derived using various basal sliding laws. This link enables the comparison of basal sliding laws within a Bayesian model selection framework (Hank et al., 2025). The posterior probabilities (also included in this dataset) were determined by the authors to infer the most probable basal sliding law. This work was funded by the GHOST project, a component of the International Thwaites Glacier Collaboration (ITGC). Support from National Science Foundation (NSF: Grant PLR 1738934) and Natural Environment Research Council (NERC: Grant NE/S006672/1), with logistics provided by NSF-U.S. Antarctic Program and NERC-British Antarctic Survey. No credit. completed Hank, Kevin British Antarctic Survey Researcher author Arthern, Robert British Antarctic Survey Researcher author Williams, C Rosie 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 > Glacier Thickness/Ice Sheet Thickness EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glaciers EARTH SCIENCE > Hydrosphere > Glaciers/Ice Sheets > Glacier Motion/Ice Sheet Motion EARTH SCIENCE > Hydrosphere > Glaciers/Ice Sheets > Glacier Thickness/Ice Sheet Thickness EARTH SCIENCE > Hydrosphere > Glaciers/Ice Sheets > Glaciers 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 Bayesian model selection ITGC Pine Island Glacier acoustic impedance basal sliding effective pressure theme Amundsen Sea sector, Pine Island Glacier Antarctica place Elevation Hydrography 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 Data supplied under Open Government Licence v3.0 otherRestrictions No restrictions apply. url url crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference url url dependency url url largerWorkCitation url url largerWorkCitation textTable eng utf8 inlandWaters -135.0 -80.0 -90.0 -60.0 2024-11-13 2025-09-01 0.0 5000.0 urn:ogc:def:crs:EPSG::5714 MSL height Not specific to any location or epoch. Hydrography. 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 bytes 88905823027 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=c560ce43-7aa0-4474-90ed-d4ee5f5768ea WWW:LINK-1.0-http--link Get Data Download data download bytes 88905823027 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=c560ce43-7aa0-4474-90ed-d4ee5f5768ea WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: The misfit between measured and predicted acoustic impedance is used to infer the most probable basal sliding law, as described in Hank et al. (2025). This methodology utilizes the dependence of predicted acoustic impedance on effective pressure, as described by the Viscous Grain-Shearing theory (VGS; Buckingham, 1997, 2000, 2005, 2007). The effective pressure is determined based on the basal sliding laws. Usually, these laws are expressed so that basal drag is a function of sliding speed and effective pressure. To compute effective pressure, these relationships must be inverted, either by explicitly rearranging the equations or by numerical root-finding. For all sliding laws, we ensure the effective pressure does not exceed the ice overburden pressure. The VGS provides a model of acoustic propagation in granular material. Substituting the estimated effective pressure (from the basal sliding law) into this model and using independent estimates for the grain diameter and porosity from sediment cores provides an estimate of acoustic impedance for each sliding law. The predicted acoustic impedance is then compared to acoustic impedance measurements collected at five sites on Pine Island Glacier (PIG) in Antarctica (Brisbourne et al., 2017). More specifically, the different models (VGS + sliding laws) are compared using Bayesian model selection. We assume the error of the data follows a Gaussian distribution and consider each model equally probable at the beginning. Since the parameter space differs between the models (number of individual parameters (dimensions) as well as number of tested parameter values), we apply Occam's razor, penalizing models with a larger parameter space. Details of all other data sets, including the basal drag and sliding speed inversion (Arthern et al., 2015) as well as the prior distributions, can be found in Hank et al. (2025). The contributing datasets used to constrain the model and parameter ranges are listed by Hank et al. (2025). The model was run between Nov 13, 2024 and Mar 11, 2025. The output is from the same date range. Data collection: The misfit calculations were performed using Julia version 1.8.3. The Bayesian model selection and all other data processing was done using Python version 3.13.2. Data quality: Key experiments were repeated with (log-)uniform prior distributions for all parameters to examine the sensitivity to the choice of the prior. Furthermore, experiments with a sub-sampled data set (every 10th acoustic impedance measurement) were carried out. A value of NaN indicates there is no data there. asNeeded completed