Ice surface, ice base and lake bed elevation data from seismic data acquired over Subglacial Lake Ellsworth 2007-08

• Main Authors: Smith, Andrew, Woodward, John, Ross, Neil
• Format: Dataset
• Language: English
• Published: UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation 2020
• Subjects: "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS","GLACIER ELEVATION/ICE SHEET ELEVATION"; "EARTH SCIENCE","LAND SURFACE","TOPOGRAPHY","TERRAIN ELEVATION"; "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS"; Subglacial Lake Ellsworth; West Antarctica; lake-bed elevation; seismic; Antarctic; Austral; Hodgson; Woodward; Antarc*; Antarctica; British Antarctic Survey; Ice Sheet
• Online Access: https://dx.doi.org/10.5285/01f26c07-ea6c-4d89-893e-d86247874e78; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01330

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). : 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. : Seismic data were acquired with Geometrics Geode seismographs; data processing and picking were done with Landmark ProMAX. : 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.