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  • 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.

  • We present here the Bedmap3 ice thickness, bed and surface elevation aggregated points and survey lines. 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 added points since the last release of Bedmap2. The data comes from 14 different data providers and 75 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

  • This dataset contains bed and surface elevation picks derived from airborne radar collected during the POLARGAP 2015/16 project 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). This collaborative project collected ~38,000 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 primary objective of the POLARGAP campaign was to carry out an airborne gravity survey covering the southern polar gap beyond the coverage of the GOCE orbit. This dataset covers the South Pole as well as parts of the Support Force, Foundation and Recovery Glaciers. The bed pick data acquired during the POLARGAP survey over the Recovery Lakes is archived at NPI: https://doi.org/10.21334/npolar.2019.ae99f750.

  • This dataset contains the position and depth of four spatially-extensive Internal Reflecting Horizons (or IRHs) traced on the British Antarctic Survey''s PASIN system and NASA Operation IceBridge''s MCoRDS2 system across the Pine Island Glacier catchment. Using the WAIS Divide ice-core chronology and a 1-D steady-state model, we assign ages to our four IRHs: (R1) 2.31-2.92 ka, (R2) 4.72 +/- 0.28 ka, (R3) 6.94 +/- 0.31 ka, and (R4) 16.50 +/- 0.79 ka. This project was funded by the UK Natural Environment Research Council Grant NE/L002558/1

  • 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 dataset includes ~3,000 line km of radio-echo sounding data along the English Coast of western Palmer Land in the Antarctic Peninsula. Data was acquired by the British Antarctic Survey Polarimetric-radar Airborne Science Instrument (PASIN2) ice sounding radar system in the austral summer of 2016/2017. Radar lines collected at ~3-5 km line spacing transect a number of outlet glacier flows, close to the grounding line, where continental ice begins to float. Data were funded by a BAS National Capability grant.

  • An airborne radar survey was flown as part of the BBAS science programme funded by the British Antarctic Survey over the Pine Island Glacier system during the austral summer of 2004/05. This survey was a collaborative US/UK field campaign which undertook a systematic geophysical survey of the entire Amundsen Sea embayment using comparable airborne survey systems mounted in Twin Otter aircraft. Operating from a temporary field camp (PNE, S 77deg34'' W 095deg56''), we collected ~35,000 km of airborne survey data. Our aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, gravity meter, and the first version of a new ice-sounding radar system (PASIN) used for the first time to support 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.

  • 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.

  • An airborne radar survey was flown over the Institute and Moller ice streams in the Weddell Sea sector of West Antarctica in the austral summer of 2010/11 as part of the Institute-Moller Antarctic Funding Initiative (IMAFI) project (grant reference number: NE/G013071/1). This project was a NERC Antarctic Funding Initiative (AFI) collaborative project between the British Antarctic Survey and the Universities of Edinburgh, York, Aberdeen and Exeter with the aim to test the hypothesis that the Institute and Moller ice streams are underlain by weak marine sediments which control the flow of the overlying ice. Operating from two static field camps close to the ice divide between the Institute and Moller ice streams and Patriot Hills, we collected ~25,000 km of airborne radio-echo sounding data across 28 survey lines. Our aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, a LaCoste and Romberg air-sea gravimeter, and an ice-sounding radar system (PASIN). 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 data set corresponds to 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 data set includes the processed SAR images as depth profiles in the Recovery Ice Stream and Rutford Ice Stream, respectively downstream and upstream of the grounding line, and respectively for the 2016/17 FISS (Filchner Ice Shelf System) and the 2019/20 BEAMISH (Bed Access, Monitoring and Ice Sheet History) projects, both during the Antarctic Summer. 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; however, in the two SAR images of the current dataset the port/starboard ambiguities are not resolved. On this dataset the user will be able to apply the RGB Doppler Decomposition method in the Doppler domain, interpret the results, and modify the different parameters and colours to contrast the results, all with the outcome of conducting new decompositions according to other datasets and needs. The RGB Spectral Decomposition is a generalised framework to interpret the SAR images: first, the Doppler or range spectral domains are first split into three sub-bandwidths; next, to each of the three a colour of a triplet of colours is assigned; and finally the three are superposed into one single image by the addition of the three colours. If the decomposition is applied on the Doppler spectrum, the new image contains the directional information related to the Doppler frequencies: positive frequencies when the radar approaches the target, near zero frequencies when the relative distance from radar to target is near stationary, and negative when the radar leaves it behind. If the backscattering is characterised by a very broad beamwidth the target will be gray/white, and if by a very narrow beamwidth then the target will be represented by one of the colours of the triplet. This work has received funding from the NERC grant NE/L013444/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica. The 2016/17 data were collected as part of the NERC grant NE/L013770/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica. The 2019/20 data were collected as part of the BAS National Capability contribution to the NERC/NSF International Thwaites Glacier Collaboration (ITGC) program.