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

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  • A digital elevation model of the bed of Rutford Ice Stream, Antarctica, derived from radio-echo sounding data. The data cover an 18 x 40 km area immediately upstream of the grounding line of the ice stream. This area is of particular interest because repeated seismic surveys have shown that rapid erosion and deposition of subglacial sediments has taken place. The bed topography shows a range of different subglacial landforms including mega-scale glacial lineations, drumlins and hummocks. This dataset will form a baseline survey which, when compared to future surveys, should reveal how active subglacial landscapes change over time. The dataset comprises observed ice thickness data, an interpolated bed elevation grid, observed surface elevation data and a surface elevation grid.

  • A time series of the mean surface elevation along a transect across Kangerdlugssuaq Glacier from Feb 2012 to May 2018. Funding: Data were processed under NERC project CALISMO NE/P011365/1. Data were acquired under NERC project NE/I007148/1. Data were supplied by DLR.

  • This data set corresponds to the processing of data acquired by the British Antarctic Survey (BAS) airborne Synthetic Aperture Radar (SAR) PASIN2 (Polarimetric Airborne Scientific INstrument, mark 2), designed for deep ice sounding and basal 3D-mapping. The dataset includes the processed calibration data collected over the sea surface near Rothera Research Station during the Antarctic Summers campaigns in 2016/17 FISS (Filchner Ice Shelf System) and 2019/20 BEAMISH (Bed Access, Monitoring and Ice Sheet History) projects, and the processed SAR images as depth profiles in the Recovery Ice Stream near its grounding line, in 2016/17 (FISS). With multiple antennas for transmission and reception at 150-MHz central frequency, and an across-track physical array, PASIN2 resolves the ambiguities for distinguishing between scatterers from port and starboard directions. After processing several 2D SAR images (range and along-track dimensions) with transmitter-receiver pairs, the directional ambiguities are resolved, obtaining the across-track Direction of Arrival (DoA, elevation angle) estimation. Finally, from the 3D geometry of range, along-track and across-track angle, the real depths and across-track distances are estimated, regarding the case of the incorrectly assumed vertical DoA of a single SAR image. The calibration flights assessed and validated the instrument antenna patterns and processing performances. In this dataset, only the simulated and measured antenna patterns, and SAR and DoA images are included. By resolving directional ambiguities and accounting for reflector across-track location, the true ice thickness and bed elevation are obtained, thereby removing the error of the usual assumption of vertical DoA, that greatly influence the output of flow models of ice dynamics. This work was supported by NERC grant reference NE/L013444/1.

  • This dataset contains bed and surface elevation picks derived from airborne radar collected in 2016/17 over the Filchner Ice Shelf and Halley Ice Shelf (West Antarctica) as part of the 5-year Filchner Ice Shelf System (FISS) project funded by NERC (grant reference number: NE/L013770/1) and awarded to the British Antarctic Survey with contribution from the National Oceanography Centre, the Met Office Hadley Centre, University College London, the University of Exeter, Oxford University, and the Alfred Wenger Institute. The aim of this project was 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. This collaborative initiative collected ~15,000 line-km of new aerogeophysical data using the 150MHz PASIN radar echo sounding system (Corr et al., 2007) deployed on a British Antarctic Survey (BAS) Twin Otter. The majority of flights were flown as part of FISS over the Support Force, Recovery, Slessor, and Bailey ice streams. Separate flights over Halley 6 research station and Brunt Ice Shelf were also collected as part of this season. The bed and surface elevation picks for the English Coast part of this season are available at: https://doi.org/10.5285/e07d62bf-d58c-4187-a019-59be998939cc.

  • A new subglacial bed Digital Elevation Model (DEM) from Ellsworth Subglacial Highlands (ESH) was created from previously gridded bed elevation data and new unpublished radar data. The new DEM includes the upper reaches of Pine Island Glacier, Rutford and Institute Ice Streams and reveals new topographical features. The main findings on this new DEM are two linear deep throughs with a perpendicular transection valley near Subglacial Lake Ellsworth. Additionally, using the new DEM and ice surface elevation data from CryoSat2 ice surface DEM, a hydropotential model was built and used to create a detailed hydropotential model of ESH to simulate the subglacial hydrological network. This approach allowed us to characterize basal hydrology, subglacial water catchments and connections between them. In this characterization we noticed the mismatch between subglacial hydrological catchment and ice surfaces catchment of Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier. Funding was provided by NERC Antarctic Funding Initiative (AFI) grants NE/D008751/1, NE/D009200/1, and NE/D008638/1, and NERC grant NE/G013071/1.

  • We present here Bedmap2 (2013), a suite of gridded products describing surface elevation, ice-thickness and the sea floor and subglacial bed elevation of the Antarctic south of 60deg S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1. In most parts of Antarctica the subglacial landscape is visible in much greater detail than was previously available and the improved data coverage has in many areas revealed the full scale of mountain ranges, valleys, basins and troughs, only fragments of which were previously indicated in local surveys. The derived statistics for Bedmap2 show that the volume of ice contained in the Antarctic ice sheet (27 million km3) and its potential contribution to sea-level rise (58 m) are similar to those of Bedmap1, but the mean thickness of the ice sheet is 4.6 % greater, the mean depth of the bed beneath the grounded ice sheet is 72 m lower and the area of ice sheet grounded on bed below sea level is increased by 10 %. The Bedmap2 compilation highlights several areas beneath the ice sheet where the bed elevation is substantially lower than the deepest bed indicated by Bedmap1. These products, along with grids of data coverage and uncertainty, provide new opportunities for detailed modelling of the past and future evolution of the Antarctic ice sheets. The associated Bedmap datasets are listed here: https://www.bas.ac.uk/project/bedmap/#data The compilation of Bedmap2 products was undertaken within the British Antarctic Survey''s programme, Polar Science for Planet Earth.

  • Improved Digital Elevation Model (DEM) of the Greenland Ice Sheet derived from Global Navigation Satellite Systems-Reflectometry (GNSS-R). This builds on a previous study (Cartwright et al., 2018) using GNSS-R to derive an Antarctic DEM but uses improved processing and an additional 13 months of measurements. A median bias of under 10 m and root-mean-square (RMS) errors of under 166 m are obtained, as compared to existing DEMs. Funding was provided by NERC grant NE/L002531/1.

  • 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.

  • We present here the Bedmap1 ice thickness, bed and surface elevation aggregated points. The aggregated points consist of statistically-summarised shapefile points (centred on a continent-wide 500 m x 500 m grid) that reports the average values of Antarctic ice thickness, bed and surface elevation from the full-resolution survey data and information on their distribution. The points presented here correspond to the points used to grid Bedmap1. The data comes from 127 individual surveys. They are available as geopackages and shapefiles. 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

  • Two maps of surface elevation change for Thwaites Glacier, West Antarctica. Change is in metres between 2013-12-21 and 2017-07-11, and between 2017-07-11 and 2020-11-02. The work was funded by NERC projects NE/P011365/1 and NE/S006605/1.