Rutford Ice Stream Antarctica
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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.
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Radar-derived bed reflectivity of Rutford Ice Stream, West Antarctica, December 2016 to January 2017
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.
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This dataset contains ASCII files with hypocenter information, event times and magnitudes for 227029 micro-earthquakes with a magnitude range from -2.0 to -0.3 recorded from a 35-station seismic network located ~40 km upstream of the grounding line of Rutford Ice Stream, West Antarctica. For 87910 of these events, earthquake focal mechanisms (strike/dip/rake) are available. The seismic network, which recordings are the base for the event catalogue, broadly formed a rectangle with 1 km station spacing. Details on the station locations, instrument types and operation periods are included in these data files. The event catalogue encloses the geographic region between 084.142 to 083.760 degrees West and 78.204 to 78.113 degrees South. Events are located between 1.553 and 2.416 km depth. Recording took place between 20th November 2018 and 16th February 2019. The spatio-temporal arrangement of these micro-earthquakes can be used to characterize frictional properties at the ice-bed interface of Rutford Ice Stream. This work was funded within the BEAMISH project by NERC AFI award numbers NE/G014159/1 and NE/G013187/1. Seismic instruments were provided by NERC SEIS-UK (Loan 1017) and the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech.
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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.
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Dual-frequency GPS data from a single receiver installed on the surface of Rutford Ice Stream in West Antarctica. The instrument was operated from late 2004 to early 2007. Gaps in the data set occur, through periods of power loss in the winters and during station relocations. Funding was provided by NERC Antarctic Funding Initiative (AFI) GR3/G005, NERC under the British Antarctic Survey National Capability programme, Polar Science for Planet Earth, Leverhulme Trust Fellowship (to T Murray), and RCUK Academic Fellowship (to M A King).
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A ground-based radar survey consisting of 35 discrete quad-polarization measurement sites over three field seasons was undertaken on Rutford Ice Stream, West Antarctica. Sites A01 to A10 were collected on 20 January 2017, along a profile orientated perpendicular to the ice flow direction. The 10 sites are located between the central ice flowline and the ice-stream margin along a profile of length 8.5 km with the inter-site spacing decreasing toward the ice-stream margin. Sites B01 to B10 were collected on 05 December 2019, along a profile orientated parallel to the central flowline. The sites were surveyed with the first site 4 km upstream of site A01 and the inter-site distance spacing fixed at 4 km. Sites C01 to C11 were collected on 14 December 2018, and located between sites A01 and A02 at 200 m spacing. Sites D01-D04, collected on 25 January 2019, are downstream of A01 and form a diamond shape with 800 m spacing. At each site, polarimetric radar-sounding measurements were made using an autonomous phase-sensitive radio-echo sounder (ApRES), a frequency-modulated continuous-wave radar. The ApRES has a centre frequency of 300 MHz and a bandwidth of 200 MHz, which results in a range resolution of approximately 40 cm in ice. ApRES radar data were collected as part of the BEAMISH Project (NERC AFI award numbers NE/G014159/1 and NE/G013187/1).
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Borehole temperature measurements from the upper 300 m of Rutford Ice Stream. A string of thermistors was installed into a hot-water drilled hole in February 2005. The string comprised 10 calibrated thermistors at approximately 30 m spacing. The temperature measurements provided were taken in February 2007, following ample time for the heat from the drilling process to have dissipated.
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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. ***** PLEASE BE ADVISED THIS DATA SET HAS BEEN RETRACTED ***** This data set had incorrect coordinates for one of the sites. In addition, some files were incorrectly labelled as belonging to one of the sites A new data set (see 'Related Data Set Metadata' link below) addresses these issues and also includes significant additional data, as well as updated metadata and additional authors. Hence it is a wholly new data set, rather than an updated version of this data set. Please use this new data set instead.
NERC Data Catalogue Service