Abstract:
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.
Keywords:
BEAMISH, West Antarctica, fast flowing ice stream, radar reflectivity
Schlegel, R., Brisbourne, A., King, E., Murray, T., & Smith, A. (2020). Radar-derived bed reflectivity of Rutford Ice Stream, West Antarctica, December 2016 to January 2017 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/5f68fce1-863e-4173-acdb-0ed03cca1c95
| Access Constraints: | No restrictions apply. |
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| Use Constraints: | This data is supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2020-11-30 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Rebecca Schlegel |
| Role(s) | Investigator, Technical Contact |
| Organisation | Swansea University |
| Name | Tavi Murray |
| Role(s) | Investigator |
| Organisation | Swansea University |
| Name | Andrew M Smith |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Alex M Brisbourne |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Adam Booth |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Name | Edward C King |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Roger A Clark |
| Role(s) | Investigator |
| Organisation | University of Leeds |
| Parent Dataset: | N/A |
| Reference: | Schlegel, R, Murray, T., Smith, A.M., Brisbourne, A. M., Booth, A.D., King, E.C., Clark, R.A. (2021). Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica. JGR Earth Surface, 127(1). https://doi.org/10.1029/2021JF006349 Gades, A. M., Raymond, C. F., Conway, H., & Jagobel, R. W. (2000). Bed properties of Siple Dome and adjacent ice streams, West Antarctica, inferred from radio-echo sounding measurements. Journal of Glaciology, 46(152), 88-94. https://doi.org/10.3189/172756500781833467 King, E. C., Woodward, J., & Smith, A. M. (2007). Seismic and radar observations of subglacial bed forms beneath the onset zone of Rutford Ice Stream, Antarctica. Journal of Glaciology, 53(183), 665-672. https://doi.org/10.3189/002214307784409216 Murray, T., Corr, H., Forieri, A., & Smith, A. M. (2008). Contrasts in hydrology between regions of basal deformation and sliding beneath Rutford Ice Stream, West Antarctica, mapped using radar and seismic data. Geophysical Research Letters, 35(12), 1-5. https://doi.org/10.1029/2008GL033681 Smith, A. M., & Murray, T. (2009). Bedform topography and basal conditions beneath a fast-flowing West Antarctic ice stream. Quaternary Science Reviews, 28(7-8), 584-596. https://doi.org/10.1016/j.quascirev.2008.05.010 Smith, A. M., Murray, T., Nicholls, K. W., Makinson, K., Adalgeirsdóttir, G., Behar, A. E., & Vaughan, D. G. (2007). Rapid erosion, drumlin formation, and changing hydrology beneath an Antarctic ice stream. Geology, 35(2), 127-130. https://doi.org/10.1130/G23036A.1 |
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| Quality: | The centre frequency of the DELORES dataset presented here is 3 MHz, the wavelength in ice (wave speed in ice=0.168 m ns-1) is 56 m. Lines were acquired perpendicular to the ice flow, with a 500 m spacing between them. The along track sampling is around 2 m. Data has been 2D migrated (along acquisition direction), the theoretical horizontal resolution of the dataset after 2D migration is 12 m. The bed reflection was clearly identifiable along the whole dataset. The received power is calculated within a 280 ns time window centred on, and encompassing, the bed reflection (Gades et al., 2000). |
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| Lineage: | 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). Reflectivity values were calculated following the method by Gades et al., (2000). The received power, presented in this dataset, is calculated within a 280 ns time window centred on, and encompassing, the bed reflection (Gades et al., 2000). This received power has not been corrected for englacial attenuation. A calibration of the amplitude of this dataset using a control reflection point (e.g. where the dielectric contrast is known, such as at the ice-water interface at the base of an ice shelf) has not been possible here. The reflectivity within this data therefore only represents relative reflectivity. Detailed information on how the reflectivity can be calibrated and analysed will be contained in Schlegel et al. (in prep.). |
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| Temporal Coverage: | |
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| Start Date | 2016-12-01 |
| End Date | 2017-01-31 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -78.2038 |
| Northernmost | -78.0139 |
| Longitude | |
| Westernmost | -84.5247 |
| Easternmost | -83.5254 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | N/A |
| Max Depth | N/A |
| Data Resolution: | |
| Latitude Resolution | N/A |
| Longitude Resolution | N/A |
| Horizontal Resolution Range | 500 meters - < 1 km |
| Vertical Resolution | N/A |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Rutford Ice Stream |
| Sensor(s): |
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| Data Collection: | Instrumentation: Surface radar data were acquired in 2016/17 (as part of the BEAMISH project), using the British Antarctic Survey (BAS) DELORES radar system (King et al., 2007). This system has a half-dipole length of 20 m, and radiates energy with a centre-frequency of ~3 MHz. Navigation along each line was provided by single-frequency GPS units mounted on the towing snowmobile. A sledge at the midpoint between receiver and transmitter was equipped with dual-frequency GPS receivers to provide more accurate positions for post-processing. Software: ReflexW (Sandmeier Scientific Software) as well as MATLAB for the calculation of the received power. |
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 14.1 MB |
| Distribution Format | ASCII |
| Fees | N/A |
| Data Storage: | This dataset contains one csv data file: X_Y_P_Z_Rutford_Schlegel_2020_radarreflectivity.csv The file consists of 4 columns and 310846 lines Column 1: X, x-coordinate (Antarctic Polar Stereographic coordinate system (EPSG:3031)) Column 2: Y, y-coordinate, (Antarctic Polar Stereographic coordinate system (EPSG:3031)) Column 3: P, Received Power (Volts) Column 4: Z, Two-way travel time of the bed reflection (ns) |