Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric
International audience The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES) at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle to an increased single-pole...
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ftccsdartic:oai:HAL:hal-00298502v1 2024-02-11T09:58:54+01:00 Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric Eisen, O. Hamann, I. Kipfstuhl, S. Steinhage, D. Wilhelms, F. Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI) Helmholtz-Gemeinschaft = Helmholtz Association 2007-10-19 https://hal.science/hal-00298502 https://hal.science/hal-00298502/document https://hal.science/hal-00298502/file/tc-1-1-2007.pdf en eng HAL CCSD Copernicus hal-00298502 https://hal.science/hal-00298502 https://hal.science/hal-00298502/document https://hal.science/hal-00298502/file/tc-1-1-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 1994-0424 EISSN: 1994-0416 The Cryosphere https://hal.science/hal-00298502 The Cryosphere, 2007, 1 (1), pp.1-10 [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2007 ftccsdartic 2024-01-21T00:59:53Z International audience The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES) at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle to an increased single-pole orientation seen along the ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and occurs at a depth of about 2025?2045 m at the drill site. Changes in conductivity as reflector origin are excluded by investigating the ice-core profile, synthetic RES data, and a RES profile with different electromagnetic polarisation azimuths. The reflector's magnitude shows maximum values for polarisation parallel to the nearby ice divide and disappears for polarisation perpendicular to it, identifying the orientation of the girdle to lie in the vertical plane parallel to the ice divide. Observations allow us to extrapolate the crystal orientation feature along the reflector in space, with implications for ice-sheet dynamics and modeling. Article in Journal/Newspaper Antarc* Antarctica Dronning Maud Land EPICA ice core Ice Sheet The Cryosphere Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Dronning Maud Land |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Eisen, O. Hamann, I. Kipfstuhl, S. Steinhage, D. Wilhelms, F. Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
topic_facet |
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES) at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle to an increased single-pole orientation seen along the ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and occurs at a depth of about 2025?2045 m at the drill site. Changes in conductivity as reflector origin are excluded by investigating the ice-core profile, synthetic RES data, and a RES profile with different electromagnetic polarisation azimuths. The reflector's magnitude shows maximum values for polarisation parallel to the nearby ice divide and disappears for polarisation perpendicular to it, identifying the orientation of the girdle to lie in the vertical plane parallel to the ice divide. Observations allow us to extrapolate the crystal orientation feature along the reflector in space, with implications for ice-sheet dynamics and modeling. |
author2 |
Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI) Helmholtz-Gemeinschaft = Helmholtz Association |
format |
Article in Journal/Newspaper |
author |
Eisen, O. Hamann, I. Kipfstuhl, S. Steinhage, D. Wilhelms, F. |
author_facet |
Eisen, O. Hamann, I. Kipfstuhl, S. Steinhage, D. Wilhelms, F. |
author_sort |
Eisen, O. |
title |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
title_short |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
title_full |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
title_fullStr |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
title_full_unstemmed |
Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
title_sort |
direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00298502 https://hal.science/hal-00298502/document https://hal.science/hal-00298502/file/tc-1-1-2007.pdf |
geographic |
Dronning Maud Land |
geographic_facet |
Dronning Maud Land |
genre |
Antarc* Antarctica Dronning Maud Land EPICA ice core Ice Sheet The Cryosphere |
genre_facet |
Antarc* Antarctica Dronning Maud Land EPICA ice core Ice Sheet The Cryosphere |
op_source |
ISSN: 1994-0424 EISSN: 1994-0416 The Cryosphere https://hal.science/hal-00298502 The Cryosphere, 2007, 1 (1), pp.1-10 |
op_relation |
hal-00298502 https://hal.science/hal-00298502 https://hal.science/hal-00298502/document https://hal.science/hal-00298502/file/tc-1-1-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1790594706827116544 |