Abstract:
These are vertical density profiles of snow, firn and ice reconstructed from the vertical luminosity trace of digital optical televiewer (OPTV) logs of five boreholes drilled by hot water to ~100 m depth in Larsen C Ice Shelf, Antarctica. Boreholes were drilled in austral summers of 2014 and 2015 in order to investigate the internal properties of the ice shelf, and specifically the influence of surface melting and melt pond formation on those properties.
These data are part of the NERC-funded MIDAS ('Impact of surface melt and ponding on ice shelf dynamics and stability') research project, with grant references NE/L006707/1 and NE/L005409/1. The associated borehole OPTV logs and temperature profiles are also available, as are other MIDAS datasets.
Keywords:
Antarctica, Ice boreholes, Ice shelf density, Larsen C Ice Shelf, Optical televiewer
Hubbard, B., & Ashmore, D. (2018). Borehole density profiles reconstructed from calibrated optical televiewer (OPTV) logs from the northern sector of Larsen C Ice Shelf, Antarctica (Version None) [Data set]. Polar Data Centre, Natural Environment Research Council, UK. https://doi.org/10.5285/c5fa84fb-f6e3-4780-8517-de0f78b62ea3
| Access Constraints: | No restrictions apply. |
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| Use Constraints: | This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2018-02-02 |
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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 PDC |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Prof Bryn Hubbard |
| Role(s) | Investigator, Technical Contact |
| Organisation | University of Liverpool |
| Name | Dr David Ashmore |
| Role(s) | Investigator |
| Organisation | University of Liverpool |
| Parent Dataset: | N/A |
| Reference: | Ashmore, David W., Bryn Hubbard, Adrian Luckman, Bernd Kulessa, Suzanne Bevan, Adam Booth, Peter Kuipers Munneke, Martin O'Leary, Heidi Sevestre, and Paul R. Holland. 2017. 'Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing', Journal of Geophysical Research: Earth Surface, 122: 1139-53. Hubbard, Bryn, Jean-Louis Tison, Morgane Philippe, Billie Heene, Frank Pattyn, Terry Malone, and Johannes Freitag. 2013. 'Ice-shelf density reconstructed from optical-televiewer borehole logging', Geophysical Research Letters: 2013GL058023. Hubbard, Bryn, Adrian Luckman, David W. Ashmore, Suzanne Bevan, Bernd Kulessa, Peter Kuipers Munneke, Morgane Philippe, Daniela Jansen, Adam Booth, Heidi Sevestre, Jean-Louis Tison, Martin O'Leary, and Ian Rutt. 2016. 'Massive subsurface ice formed by refreezing of ice-shelf melt ponds', Nature Communications, 7: 11897. Hubbard, Bryn, Sam Roberson, Denis Samyn, and Derek Merton-Lyn. 2008. 'Digital optical televiewing of ice boreholes', Journal of Glaciology, 54: 823-30. Malone, Terry, Bryn Hubbard, Derek Merton-Lyn, Paul Worthington, and Reyer Zwiggelaar. 2013. 'Borehole and Ice Feature Annotation Tool (BIFAT): A program for the automatic and manual annotation of glacier borehole images', Computers & Geosciences, 51: 381-89. |
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| Quality: | Density traces are provided at the same resolution, and subject to the same logging errors, as the field OPTV logs. The OPTV technique is described by Hubbard and others (2008). Most OPTV logs, and hence density profiles, are at a vertical resolution of 1 mm. |
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| Lineage: | The datasets are density profiles calculated from optical televiewer logs from five boreholes drilled to approaching 100 m depth along flow-lines extending from Cabinet Inlet and Whirlwind Inlet on Larsen C Ice Shelf, Antarctica, in austral summers of 2014 and 2015. These data are presented in whole or in part in Hubbard and others (2016) and Ashmore and others (2017). The OPTV luminosity - density calibration is presented in Hubbard (2013). Density profiles, and parent OPTV logs, and were located (at the time of logging) as follows: Borehole; Lat., Lon. (decimal degrees); Coordinate date CI_0; -66.403, -63.376; Nov 2014 CI_22; -66.588, -63.212; Nov 2015 CI_120; -67.000, -61.486; Nov 2015 WI_0; -67.444, -64.953; Dec 2015 WI_70; -67.500, -63.336; Dec 2015 |
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| Temporal Coverage: | |
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| Start Date | 2014-11-01 |
| End Date | 2015-12-31 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -67.5 |
| Northernmost | -66.403 |
| Longitude | |
| Westernmost | -64.953 |
| Easternmost | -61.486 |
| 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 | N/A |
| Vertical Resolution | 1 mm |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Laren C Ice Shelf |
| Data Collection: | Logs were acquired using Robertson Geologging OPTV probe, mini winch and Micrologger II. Luminosity traces were extracted using BIFAT (Malone et al. 2013) software. |
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| Data Storage: | The data are comma-separated ASCII files (*.csv format). Each file size is ~1 MB and there are a total of 5 files. |
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