Ice surface, ice base and lake bed elevation data from seismic data acquired over Subglacial Lake Ellsworth 2007-08
GB/NERC/BAS/PDC/01330
Abstract:
Point data measurements of ice surface, ice base and lake bed elevation are given from Subglacial Lake Ellsworth (SLE), West Antarctica. The data were acquired during the austral summer of 2007-2008. Five seismic reflection lines were acquired over SLE, with surface elevation determined by dual frequency GPS.
Funding was provided by NERC AFI, award numbers NE/D009200/1, NE/D008638/1 and NE/D008751/1. Logistics support: British Antarctic Survey. Equipment support: NERC Geophysical Equipment Facility (loan numbers 838 and 870).
Citation:
Smith, A., Woodward, J., & Ross, N. (2020). Ice surface, ice base and lake bed elevation data from seismic data acquired over Subglacial Lake Ellsworth 2007-08 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/01f26c07-ea6c-4d89-893e-d86247874e78
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License
| Access: | No restrictions apply. |
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| Use: | These data are governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
Basic Information
| Creation Date: | 2020-05-11 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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Additional Information
| Reference: | Woodward, J., A. M. Smith, N. Ross, M. Thoma, H. F. J. Corr, E. C. King, M. A. King, K. Grosfeld, M. Tranter, M. J. Siegert, 2010. Location for direct access to subglacial Lake Ellsworth: An assessment of geophysical data and modelling. Geophysical Research Letters, doi:10.1029/2010GL042884. Ross, N., Siegert, M.J., Woodward, J., Smith, A.M., Corr, H.F.J., Bentley, M.J., Hindmarsh, R.C.A., King, E.C., Rivera, A., 2011. Holocene stability of the Amundsen-Weddell ice divide, West Antarctica. Geology, doi:10.1130/G31920.1 Smith, A.M., J. Woodward, N. Ross, M.J. Bentley, D.A. Hodgson, M.J. Siegert, E.C. King, 2018. Evidence for the long-term sedimentary environment in an Antarctic subglacial lake. Earth and Planetary Science Letters, doi:10.1016/j.epsl.2018.10.011. |
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| Quality: | Data quality are good; the ice-water interface can be clearly picked on virtually all traces, the water-bed interface can be picked in most places, except close to the lake shoreline and at a few other locations on each line. Only the results from traces where both reflections can be picked are provided. Nominal point spacing is 5 m, with occasional gaps at the locations where both reflections could not be picked. Absolute errors in ice- and water-column thickness are 10 m and 1.5 m respectively, although relative thicknesses changes (trace-to-trace) are more precise. See publications for full details. | |
| Lineage/Methodology: | Five seismic reflection profiles were acquired. The seismic source was 450 g explosives at 30 m depth. Shot spacing was 240 m, number of channels was 48 and geophone spacing was 10 m, resulting in single-fold data. Data processing included normal moveout correction, and migration. Ice-water and water-bed interface reflections were picked from stacked seismic sections. Depth conversion used a travel-time correction for the upper snow and firn, and standard ice- and water-column velocities. Full details of data acquisition and processing are given in: Woodward, J., A. M. Smith, N. Ross, M. Thoma, H. F. J. Corr, E. C. King, M. A. King, K. Grosfeld, M. Tranter, M. J. Siegert, 2010. Location for direct access to subglacial Lake Ellsworth: An assessment of geophysical data and modelling. Geophysical Research Letters, doi:10.1029/2010GL042884. Smith, A.M., J. Woodward, N. Ross, M.J. Bentley, D.A. Hodgson, M.J. Siegert, E.C. King, 2018. Evidence for the long-term sedimentary environment in an Antarctic subglacial lake. Earth and Planetary Science Letters, doi:10.1016/j.epsl.2018.10.011. |
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Extent
| Temporal Coverage: | |
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| Start Date | 2007-11-01 |
| End Date | 2008-02-29 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -79.1 |
| Northernmost | -78.8 |
| Longitude | |
| Westernmost | -91 |
| Easternmost | -90 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | 1905 |
| Depth | |
| Min Depth | -1394 |
| Max Depth | N/A |
| Data Resolution: | |
| Latitude Resolution | 0.00001 degree |
| Longitude Resolution | 0.00001 degree |
| Horizontal Resolution Range | N/A |
| Vertical Resolution | 0.1 m |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Ellsworth Subglacial Lake (better known as Subglacial Lake Ellsworth) |
Instrumentation
| Sensor(s): |
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| Data Collection: | Seismic data were acquired with Geometrics Geode seismographs; data processing and picking were done with Landmark ProMAX. |
Storage
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 51.2 kB |
| Distribution Format | ASCII |
| Fees | N/A |
| Data Storage: | One comma-separated variable file is provided, comprising five columns. In sequence, columns give: latitude (degrees S), longitude (degrees W), surface elevation (m), ice-base elevation (m), lake bed elevation (m). All elevations are referenced to the WGS84 ellipsoid. |