In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness
Airborne, ship-borne and surface low-frequency electromagnetic (EM) methods have become widely applied to measure sea-ice thickness. EM responses measured over sea ice depend mainly on the sea-water conductivity and on the height of the sensor above the sea-icesea-water interface, but may be sensiti...
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ftawi:oai:epic.awi.de:14117 2023-09-05T13:12:05+02:00 In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness Reid, J. E. Pfaffling, A. Worby, A. P. Bishop, J. R. 2006 application/pdf https://epic.awi.de/id/eprint/14117/ https://epic.awi.de/id/eprint/14117/1/Ker2006b.pdf https://hdl.handle.net/10013/epic.24453 https://hdl.handle.net/10013/epic.24453.d001 unknown https://epic.awi.de/id/eprint/14117/1/Ker2006b.pdf https://hdl.handle.net/10013/epic.24453.d001 Reid, J. E. , Pfaffling, A. , Worby, A. P. and Bishop, J. R. (2006) In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness , Annals of Glaciology . hdl:10013/epic.24453 EPIC3Annals of Glaciology, 44 p. Article isiRev 2006 ftawi 2023-08-23T05:30:52Z Airborne, ship-borne and surface low-frequency electromagnetic (EM) methods have become widely applied to measure sea-ice thickness. EM responses measured over sea ice depend mainly on the sea-water conductivity and on the height of the sensor above the sea-icesea-water interface, but may be sensitive to the sea-ice conductivity at high excitation frequencies. We have conducted in situ measurements of direct-current conductivity of sea ice using standard geophysical geoelectrical methods. Sea-ice thickness estimated from the geoelectrical sounding data was found to be consistently underestimated due to the pronounced vertical-to-horizontal conductivity anisotropy present in level sea ice. At five sites, it was possible to determine the approximate horizontal and vertical conductivities from the sounding data. The average horizontal conductivity was found to be 0.017 Sm1, and that in the vertical direction to be 912 times higher. EM measurements over level sea ice are sensitive only to the horizontal conductivity. Numerical modelling has shown that the assumption of zero sea-ice conductivity in interpretation of airborne EM data results in a negligible error in interpreted thickness for typical level Antarctic sea ice. Article in Journal/Newspaper Annals of Glaciology Antarc* Antarctic Sea ice Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Antarctic |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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description |
Airborne, ship-borne and surface low-frequency electromagnetic (EM) methods have become widely applied to measure sea-ice thickness. EM responses measured over sea ice depend mainly on the sea-water conductivity and on the height of the sensor above the sea-icesea-water interface, but may be sensitive to the sea-ice conductivity at high excitation frequencies. We have conducted in situ measurements of direct-current conductivity of sea ice using standard geophysical geoelectrical methods. Sea-ice thickness estimated from the geoelectrical sounding data was found to be consistently underestimated due to the pronounced vertical-to-horizontal conductivity anisotropy present in level sea ice. At five sites, it was possible to determine the approximate horizontal and vertical conductivities from the sounding data. The average horizontal conductivity was found to be 0.017 Sm1, and that in the vertical direction to be 912 times higher. EM measurements over level sea ice are sensitive only to the horizontal conductivity. Numerical modelling has shown that the assumption of zero sea-ice conductivity in interpretation of airborne EM data results in a negligible error in interpreted thickness for typical level Antarctic sea ice. |
format |
Article in Journal/Newspaper |
author |
Reid, J. E. Pfaffling, A. Worby, A. P. Bishop, J. R. |
spellingShingle |
Reid, J. E. Pfaffling, A. Worby, A. P. Bishop, J. R. In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
author_facet |
Reid, J. E. Pfaffling, A. Worby, A. P. Bishop, J. R. |
author_sort |
Reid, J. E. |
title |
In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
title_short |
In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
title_full |
In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
title_fullStr |
In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
title_full_unstemmed |
In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
title_sort |
in-situ measurements of the direct-current conductivity of antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness |
publishDate |
2006 |
url |
https://epic.awi.de/id/eprint/14117/ https://epic.awi.de/id/eprint/14117/1/Ker2006b.pdf https://hdl.handle.net/10013/epic.24453 https://hdl.handle.net/10013/epic.24453.d001 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Annals of Glaciology Antarc* Antarctic Sea ice |
genre_facet |
Annals of Glaciology Antarc* Antarctic Sea ice |
op_source |
EPIC3Annals of Glaciology, 44 p. |
op_relation |
https://epic.awi.de/id/eprint/14117/1/Ker2006b.pdf https://hdl.handle.net/10013/epic.24453.d001 Reid, J. E. , Pfaffling, A. , Worby, A. P. and Bishop, J. R. (2006) In-situ measurements of the direct-current conductivity of Antarctic sea ice: implications for airborne electromagnetic sounding of sea-ice thickness , Annals of Glaciology . hdl:10013/epic.24453 |
_version_ |
1776198872608014336 |