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EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets > Glacier Topography/Ice Sheet Topography

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  • The dataset presented here contains a csv-file including the coordinates, received power of the bed reflection and the two-way travel time of the bed reflection. The X and Y coordinates are projected in EPSG:3031 - WGS 84 / Antarctic Polar Stereographic coordinate system. Data presented here have been frequency filtered and 2D migrated (using a finite difference approach and migration velocity of 0.168 m ns-1), followed by the picking of the bed reflection using ReflexW software (Sandmeier Scientific Software). The received power is calculated within a 280 ns time window centred on, and encompassing, the bed reflection (Gades et al., 2000). This work was funded within the BEAMISH project by NERC AFI award numbers NE/G014159/1 and NE/G013187/1.

  • We present here the Bedmap3 ice thickness, bed and surface elevation standardised CSV data points that are used to create the Bedmap3 gridding products in addition to the previous data releases. The data consists of 50 million points acquired by 17 different data providers in Antarctica. The associated Bedmap datasets are listed here: https://www.bas.ac.uk/project/bedmap/#data This work is supported by the SCAR Bedmap project and the British Antarctic Survey''s core programme: National Capability - Polar Expertise Supporting UK Research

  • We present here the Bedmap2 ice thickness, bed and surface elevation standardised CSV data points that were used to create the Bedmap2 gridding products. The data consists of 25 million points coming from 68 individual surveys acquired in Antarctica. The associated Bedmap datasets are listed here: https://www.bas.ac.uk/project/bedmap/#data This work is supported by the SCAR Bedmap project and the British Antarctic Survey''s core programme: National Capability - Polar Expertise Supporting UK Research

  • An airborne radar survey was flown during the austral summer of 2015/16 over the Foundation Ice Stream, Bungenstock Ice Rise, and the Filchner ice shelf as part of the 5-year Filchner Ice Shelf System (FISS) project. This project was a NERC-funded (grant reference number: NE/L013770/1) collaborative initiative between the British Antarctic Survey, the National Oceanography Centre, the Met Office Hadley Centre, University College London, the University of Exeter, Oxford University, and the Alfred Wenger Institute to investigate how the Filchner Ice Shelf might respond to a warmer world, and what the impact of sea-level rise could be by the middle of this century. The 2015/16 aerogeophysics survey acquired ~7,000 line km of aerogeophysical data with a particular focus on the Foundation Ice Stream. Our Twin Otter aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, and a new ice-sounding radar system (PASIN-2). 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. This is Version 2 of the dataset. This version differs from Version 1, as follows: 1. The variables "fast_time" has been updated due to errors found. The error in the variable related to an error in the sampling frequency of the system, which should have been 24 MHz instead of 22MHz. This has been updated. 2. The units in the "surface_pick_layerData" and the "bed_pick_layerData" variables should have been "samples relative to the BAS radar system", instead of "microseconds". This has been corrected. 3. The metadata in this DMS entry and in the NetCDF files has also been updated. Mainly, the sampling frequency has been modified from 22 MHz to 24 MHz to reflect the radar system characteristics. This also affected the value provided for the radar system resolution and sampling interval, which have both been updated in the metadata. 4. The SEGY sampling interval value (byte numbers: 117-118 (SI)) has also been updated to reflect the change in sampling frequency mentioned above. All other variables remain unchanged. Note that these changes do not affect the radar data or the associated radar-derived data in the files.

  • During the austral summer of 2015/16, a major international collaboration funded by the European Space Agency (ESA) and with in-kind contribution from the British Antarctic Survey, the Technical University of Denmark (DTU), the Norwegian Polar Institute (NPI) and the US National Science Foundation (NSF), acquired ~38,000 line km of aerogeophysical data. The primary objective of the POLARGAP campaign was to carry out an airborne gravity survey covering the southern polar gap of the ESA gravity field mission GOCE, beyond the coverage of the GOCE orbit (south of 83.5degS), however aeromagnetics and ice-penetrating radar data were also opportunistically acquired. This survey covers the South Pole and Recovery Lakes, as well as parts of the Support Force, Foundation and Recovery Glaciers. Our Twin Otter aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, an air-sea gravity meter, and a new ice-sounding radar system (PASIN-2). 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. This is Version 2 of the dataset. This version differs from Version 1, as follows: 1. The variables "fast_time" and "UTC_time_layerData" have been updated due to errors found. The error in the fast_time variable related to an error in the sampling frequency of the system, which should have been 24 MHz instead of 22MHz. This has been updated. The error in the "UTC_time_layerData" related to a rounding issue which affected the precision of this variable. This has been updated. 2. The units in the "surface_pick_layerData" and the "bed_pick_layerData" variables should have been "samples relative to the BAS radar system", instead of "microseconds". This has been corrected. 3. The metadata in this DMS entry and in the NetCDF files has also been updated. Mainly, the sampling frequency has been modified from 22 MHz to 24 MHz to reflect the radar system characteristics. This also affected the value provided for the radar system resolution and sampling interval, which have both been updated in the metadata. 4. The SEGY sampling interval value (byte numbers: 117-118 (SI)) has also been updated to reflect the change in sampling frequency mentioned above. All other variables remain unchanged. Note that these changes do not affect the radar data or the associated radar-derived data in the files.

  • Three separate airborne radar surveys were flown during the austral summer of 2016/17 over the Filchner Ice Shelf and Halley Ice Shelf (West Antarctica), and over the outlet glacier flows of the English Coast (western Palmer Land, Antarctic Peninsula) during the Filchner Ice Shelf System (FISS) project. This project was a NERC-funded (grant reference number: NE/L013770/1) collaborative initiative between the British Antarctic Survey, the National Oceanography Centre, the Met Office Hadley Centre, University College London, the University of Exeter, Oxford University, and the Alfred Wenger Institute to investigate how the Filchner Ice Shelf might respond to a warmer world, and what the impact of sea-level rise could be by the middle of this century. The 2016/17 aerogeophysics surveys acquired a total of ~26,000 line km of aerogeophysical data. The FISS survey consisted of 17 survey flights totalling ~16,000 km of radar data over the Support Force, Recovery, Slessor, and Bailey ice streams of the Filchner Ice Shelf. The Halley Ice Shelf survey consisted of ~4,600 km spread over 5 flights and covering the area around the BAS Halley 6 station and the Brunt Ice Shelf. The English Coast survey consisted of ~5,000 km spread over 7 flights departing from the Sky Blu basecamp and linking several outlet glacier flows and the grounding line of the western Palmer Land, including the ENVISAT, CRYOSAT, GRACE, Landsat, Sentinel, ERS, Hall, Nikitin and Lidke ice streams. Our Twin Otter aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, an iMAR strapdown gravity system, and a new ice-sounding radar system (PASIN-2). 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. This is Version 2 of the dataset. This version differs from Version 1, as follows: 1. The variables "fast_time" has been updated due to errors found. The error in the variable related to an error in the sampling frequency of the system, which should have been 24 MHz instead of 22MHz. This has been updated. 2. The units in the "surface_pick_layerData" and the "bed_pick_layerData" variables should have been "samples relative to the BAS radar system", instead of "microseconds". This has been corrected. 3. The metadata in this DMS entry and in the NetCDF files has also been updated. Mainly, the sampling frequency has been modified from 22 MHz to 24 MHz to reflect the radar system characteristics. This also affected the value provided for the radar system resolution and sampling interval, which have both been updated in the metadata. 4. The SEGY sampling interval value (byte numbers: 117-118 (SI)) has also been updated to reflect the change in sampling frequency mentioned above. All other variables remain unchanged. Note that these changes do not affect the radar data or the associated radar-derived data in the files.

  • We present here the Bedmap1 ice thickness, bed and surface elevation standardised CSV data points that were used to create the Bedmap1 gridding products. The data consists of 2 million data points acquired in Antarctica from 1960s to 2000. The associated Bedmap datasets are listed here: https://www.bas.ac.uk/project/bedmap/#data This work is supported by the SCAR Bedmap project and the British Antarctic Survey''s core programme: National Capability - Polar Expertise Supporting UK Research

  • The dataset contains depth information (in meters) for pixels of subglacial overdeepenings with an area of 10000 m2 or larger, across five regions: Alaska, European Alps, New Zealand Southern Alps, the Central Himalayas, and the Peruvian Andes. These overdeepenings were derived by subtracting ice thickness data from Digital Elevation Models (DEMs) that describe the surface topography. Five ice thickness models were used for all regions: Farinotti''s Ensemble, GlabTop2, Huss and Farinotti were downloaded from Farinotti et al., (2019). OGGM''s ice thickness was downloaded from Farinotti et al., 2019 for all regions except for the Himalayas where it was generated by keeping the default same. Millan''s ice thickness was downloaded from Millan et al., (2022). The primary DEM used was the ALOS PALSAR DEM. For Central Himalayas, in addition to ALOS PALSAR, three other DEMs were used: ASTER, SRTM, and Copernicus. NERC standard grant NE/S013318/1.

  • The dataset presented here focuses on the area of a prominent bedform beneath the Rutford Ice Stream, referred to as "the Bump". The provided dataset contains several CSV files including the coordinates, two-way travel time of the bed reflection, the reflectivity of the bed reflection and acoustic impedance of the bed reflection, respectively. The X and Y coordinates are projected in EPSG:3031 - WGS 84 / Antarctic Polar Stereographic coordinate system. Radar topography presented here were frequency filtered and 3D migrated (using a 3D Kirchhoff Time Migration approach in SeisSpace/ProMAX (LGCHalliburton Software) and migration velocity of 0.168 m ns-1), followed by the picking of the bed reflection using Petrel (Schlumberger Software). Radar reflectivity was calculated from 2D migrated radar data following the processing routine as described in Schlegel et al. (2022) including frequency filtering and 2D migration in SeisSpace/ProMAX. Seismic acoustic impedance of the bed reflection was calculated following Smith et al. (2007). This work was funded within the BEAMISH project by NERC AFI award numbers NE/G014159/1 and NE/G013187/1 and NE/F015879/1, and by NERC National Capability Science: Strategic Research & Innovation Short Projects. The University of Leeds acknowledges the support of this work by Landmark Software and Services, a Landmark Company and use of SeisSpace/ProMAX via the Landmark University Grant Program, Agreements 2004-COM-024982, 2008-CON-010888 and subsequent renewals.

  • High-resolution basal topography and basal properties were calculated from two 3x3 km2 radar datasets acquired approximately 50 km upstream of the grounding line of Rutford Ice Stream in West Antarctica. The provided datasets contain several csv-files including the coordinates, bed elevation below the WGS84 ellipsoid and the reflectivity of the bed reflection. The X and Y coordinates are projected in EPSG:3031 - WGS 84 / Antarctic Polar Stereographic coordinate system. Radar data were acquired between December 2017 and late January 2018 using the British Antarctic Survey''s ground-based DELORES system as part of the BEAMISH project. Data acquisition and processing was compliant with 3D processing and migration. Radar data were frequency filtered and 3D migrated (using a 3D Kirchhoff Time Migration approach in SeisSpace/ProMAX (LGCHalliburton Software) and migration velocity of 0.168 m ns-1), followed by the picking of the bed reflection using Petrel (Schlumberger Software). For the interpretation of variation of bed properties, basal reflectivity was calculated as described in Schlegel et al., 2022 and Schlegel et al., 2024. This work was funded by NERC AFI award numbers NE/G014159/1, NE/G013187/1 and NE/F015879/1, and NERC National Capability Science: Strategic Research and Innovation Short Projects. Geophysical equipment was provided by NERC''s Geophysical Equipment Facility, loan number 887. We thank BAS Operations and N. Gillett for fieldwork support and B. Craven for software support. University of Leeds acknowledges support of this work by Landmark Software and Services, a Landmark Company and use of SeisSpace/ProMAX via the Landmark University Grant Program, Agreements 2004-COM-024982, 2008-CON-010888 and subsequent renewals. The British Antarctic Survey acknowledges support of this work by Landmark Software and Services, a Landmark Company.