c7ea5697-87e3-4529-a0dd-089a2ed638fb 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 2021-06-30 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 Processed airborne radio-echo sounding data from the GRADES-IMAGE survey covering the Evans and Rutford Ice Streams, and ice rises in the Ronne Ice Shelf, West Antarctica (2006/2007) 2021-06-30 creation 2021-06-30 revision 2021-06-30 publication 2021-06-30 released 1.0 https://doi.org/10.5285/c7ea5697-87e3-4529-a0dd-089a2ed638fb doi GB/NERC/BAS/PDC/01515 https://data.bas.ac.uk/ Please cite this item as: Corr, H. (2021). Processed airborne radio-echo sounding data from the GRADES-IMAGE survey covering the Evans and Rutford Ice Streams, and ice rises in the Ronne Ice Shelf, West Antarctica (2006/2007) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/c7ea5697-87e3-4529-a0dd-089a2ed638fb An airborne radar survey was flown as part of the GRADES-IMAGE project funded by BAS over the Antarctic Peninsula, Ellsworth Mountains and Filchner-Ronne Ice Shelf (also including the Evans Ice stream and Carson Inlet) mainly to image englacial layers and bedrock topography during the 2006/07 field season. Operating from temporary field camps at Sky Blu, Partiot Hills and out of RABID depot (Rutford Ice Stream), we collected ~27,550 km of airborne radio-echo sounding data over 100 hours of surveying. Our aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, and an ice-sounding radar system (PASIN). Note that there was no gravimetric element to this survey. We present here the full radar dataset consisting of the deep-sounding chirp and shallow-sounding pulse-acquired data in their processed form, as well as the navigational information of each trace, the surface and bed elevation picks, ice thickness, and calculated absolute surface and bed elevations. This dataset comes primarily in the form of NetCDF and georeferenced SEGY files. To interactively engage with this newly-published dataset, we also created segmented quicklook PDF files of the radar data. No credit. completed Corr, Hugh 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 Elevation/Ice Sheet Elevation EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glacier Thickness/Ice Sheet Thickness EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glacier Topography/Ice Sheet Topography EARTH SCIENCE > Spectral/Engineering > Radar > Radar Imagery EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets 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 Antarctic aerogeophysics ice thickness radar surface elevation theme Ronne Ice Shelf 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 governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/ otherRestrictions . Further by downloading this data the user acknowledges that they agree with the NERC data policy (), and the following conditions: 1. To cite the data in any publication as follows: Corr, H. (2021). Processed airborne radio-echo sounding data from the GRADES-IMAGE survey covering the Evans and Rutford Ice Streams, and ice rises in the Ronne Ice Shelf, West Antarctica (2006/2007) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/C7EA5697-87E3-4529-A0DD-089A2ED638FB 2. The user recognizes the limitations of data. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data. otherRestrictions None url url crossReference doi doi crossReference doi doi crossReference doi doi crossReference doi doi crossReference textTable eng utf8 elevation geoscientificInformation -88.9669 -61.292 -81.9457 -67.9541 2006-12-29 2007-01-30 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/pdf application/x-hdf application/octet-stream bytes 24803436134 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=c7ea5697-87e3-4529-a0dd-089a2ed638fb WWW:LINK-1.0-http--link Get Data Download data download bytes 24803436134 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=c7ea5697-87e3-4529-a0dd-089a2ed638fb WWW:LINK-1.0-http--link Get Data Download data download bytes 24803436134 https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=c7ea5697-87e3-4529-a0dd-089a2ed638fb WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: ** Instrumentation and Processing: Radar data were collected using the bistatic PASIN radar echo sounding system mounted on the BAS Twin Otter aircraft "Bravo Lima" and operating with a centre frequency of 150 MHz and using two interleaved pulses: a 4-microseconds, 10 MHz bandwidth linear chirp (deep sounding) and a 0.1-microseconds unmodulated pulse (shallow sounding). Chirp compression was applied using a Blackman window to minimise sidelobe levels, resulting in a processing gain of 10 dB. The chirp data was processed using an coherent averaging filter (commonly referred to as unfocused Synthetic Aperture Radar (SAR) processing) along a moving window of length 15. This product is best used to assess the bed and internals in deep ice conditions. The pulse data was processed using an incoherent averaging filter along a moving window of length 25 and using a combination of the upper and lower channels. This data is best used to assess the internal structure and bed in shallow ice conditions. The bed reflector was first automatically depicted on the chirp data using a semi-automatic picker in the PROMAX software package. All the picks were afterwards checked and corrected by hand if necessary. The picked travel time was then converted to depth using a radar wave speed of 168 m/microseconds and a constant firn correction of 10 m. Surface elevation is derived from radar altimeter for ground clearance < 750 m, and the PASIN system for higher altitudes. ** Coordinates and Positions: The coordinates provided in the NetCDF for the surface and bed elevation for each radar trace are in longitude and latitude (WGS84, EPSG: 4326). The navigation attributes for the radar data in the NetCDF are in projected X and Y coordinates (Polar Stereographic, EPSG: 3031), as follows: Latitude of natural origin: -71 Longitude of natural origin: 0 Scale factor at natural origin: 0.994 False easting: 0 False northing: 2082760.109 The coordinates in the SEGY data are also in projected X and Y coordinates (Polar Stereographic, EPSG: 3031), although note that these are in integer format due to the SEGY limitations (see section below). Positions are calculated for the phase centre of the aircraft antenna. All positions (Longitude, Latitude and Height) are referred to the WGS1984 ellipsoid. ** Dataset: Please note: Due to the unstable nature of SEGY-formatted data and its uncertain long-term future, as well as the issues documented below, we also provide the full radar data in NetCDF format. The dataset provided here consists of three parts: a NetCDF file per flightline, two SEGY files per flightline (one chirp and one pulse), and one quicklook PDF file per flightline. These are described in more details below. - NetCDF: The NetCDF files contain the deep-sounding chirp and shallow-sounding pulse-acquired data in their processed form, as well as the associated metadata, navigational information (in both EPSG: 3031 and WGS84 EPSG: 4326), and the associated radar-related information for each trace (e.g. surface/bed elevation and picks, ice thickness, aircraft altitude, range to surface, time of trace) which are provided as separate attributes in the NetCDF file. The navigational position of each trace comes from the surface files, and the processed GPS files when no surface information was provided in the surface files. Note that for these, interpolation of the navigational data might have been required to match closely the Coordinated Universal Time (UTC) of each trace in the surface files. No data is shown as "-9999" throughout the files. NetCDF attributes: - 'traces': Trace number for the radar data (x axis) - 'fast_time': Two-way travel time (y axis) (units: microseconds) - 'x_coordinates': Cartesian x-coordinates for the radar data (x axis) (units: meters in WGS84 EPSG:3031) - 'y_coordinates': Cartesian y-co...(53) Data collection: ** Instrument: Radar data were collected using the bistatic PASIN (Polarimetric radar Airborne Science Instrument) radar echo sounding system mounted on the BAS Twin Otter aircraft "Bravo Lima" and operating with a centre frequency of 150 MHz and using two interleaved pulses: a 4-microseconds, 10 MHz bandwidth linear chirp (deep sounding) and a 0.1-microseconds unmodulated pulse (shallow sounding). The Pulse Repetition Frequency was 15,635 Hz (pulse repetition interval: 64 microseconds). ** Antenna configuration: 8 folded dipole elements: 4 transmitters (port side) 4 receivers (starboard side) Antenna gain: 11 dBi (with 4 elements) Transmit power: 1 kW into each 4 antennae Maximum transmit duty cycle: 10% at full power (4 x 1 kW) ** Radar receiver configuration: Receiver vertical sampling frequency: 22 MHz (resulting in sampling interval of 45.4546 ns) Receiver coherent stacking: 25 Receiver digital filtering: -50 dBc at Nyquist (11 MHz) Effective PRF: 312.5 Hz (post-hardware stacking) Sustained data rate: 10.56 Mbytes/second Data quality: - Trace spacing (post-processed data): ~20 m - Vertical resolution: ~8.4 m - Radar centre frequency: 150 MHz - Radar bandwidth: 10 MHz - Radar Receiver vertical sampling frequency: 22 MHz - Absolute GPS positional accuracy: ~0.1 m (relative accuracy is one order of magnitude better). Banking angle was limited to 10 deg during aircraft turns to avoid phase issues between GPS receiver and transmitter. Please note: The surface and bed pick information (surface and bed elevation, ice thickness, etc.) can also be found at: https://doi.org/10.5285/4efa688e-7659-4cbf-a72f-facac5d63998.The datasets found here have been considerably curated and improved, and thus can be considered the latest and full dataset. asNeeded completed