Layer disturbances and the radio-echo free zone in ice sheets
Radio-echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of radio echoes, known as the echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare e...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00029950 2023-05-15T13:36:44+02:00 Layer disturbances and the radio-echo free zone in ice sheets Drews, R. Eisen, O. Weikusat, I. Kipfstuhl, S. Lambrecht, A. Steinhage, D. Wilhelms, F. Miller, H. 2009-08 electronic https://doi.org/10.5194/tc-3-195-2009 https://noa.gwlb.de/receive/cop_mods_00029950 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00029904/tc-3-195-2009.pdf https://tc.copernicus.org/articles/3/195/2009/tc-3-195-2009.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-3-195-2009 https://noa.gwlb.de/receive/cop_mods_00029950 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00029904/tc-3-195-2009.pdf https://tc.copernicus.org/articles/3/195/2009/tc-3-195-2009.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2009 ftnonlinearchiv https://doi.org/10.5194/tc-3-195-2009 2022-02-08T22:47:28Z Radio-echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of radio echoes, known as the echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare echoes around the EPICA drill site in Dronning Maud Land, Antarctica, with the dielectric properties, crystal orientation fabrics and optical stratigraphy of the EPICA-DML ice core. We find that echoes disappear in the depth range where the dielectric contrast is blurred, and where the coherency of the layers in the ice core is lost due to disturbances caused by the ice flow. At the drill site, the EFZ onset at ~2100 m marks a boundary, below which the ice core may have experienced flow induced disturbances on various scales. The onset may indicate changing rheology which needs to be accounted for in the modeling of ice sheet dynamics. Article in Journal/Newspaper Antarc* Antarctic Antarctica DML Dronning Maud Land EPICA greenlandic ice core Ice Sheet The Cryosphere Niedersächsisches Online-Archiv NOA Antarctic The Antarctic Dronning Maud Land The Cryosphere 3 2 195 203 |
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article Verlagsveröffentlichung Drews, R. Eisen, O. Weikusat, I. Kipfstuhl, S. Lambrecht, A. Steinhage, D. Wilhelms, F. Miller, H. Layer disturbances and the radio-echo free zone in ice sheets |
topic_facet |
article Verlagsveröffentlichung |
description |
Radio-echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of radio echoes, known as the echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare echoes around the EPICA drill site in Dronning Maud Land, Antarctica, with the dielectric properties, crystal orientation fabrics and optical stratigraphy of the EPICA-DML ice core. We find that echoes disappear in the depth range where the dielectric contrast is blurred, and where the coherency of the layers in the ice core is lost due to disturbances caused by the ice flow. At the drill site, the EFZ onset at ~2100 m marks a boundary, below which the ice core may have experienced flow induced disturbances on various scales. The onset may indicate changing rheology which needs to be accounted for in the modeling of ice sheet dynamics. |
format |
Article in Journal/Newspaper |
author |
Drews, R. Eisen, O. Weikusat, I. Kipfstuhl, S. Lambrecht, A. Steinhage, D. Wilhelms, F. Miller, H. |
author_facet |
Drews, R. Eisen, O. Weikusat, I. Kipfstuhl, S. Lambrecht, A. Steinhage, D. Wilhelms, F. Miller, H. |
author_sort |
Drews, R. |
title |
Layer disturbances and the radio-echo free zone in ice sheets |
title_short |
Layer disturbances and the radio-echo free zone in ice sheets |
title_full |
Layer disturbances and the radio-echo free zone in ice sheets |
title_fullStr |
Layer disturbances and the radio-echo free zone in ice sheets |
title_full_unstemmed |
Layer disturbances and the radio-echo free zone in ice sheets |
title_sort |
layer disturbances and the radio-echo free zone in ice sheets |
publisher |
Copernicus Publications |
publishDate |
2009 |
url |
https://doi.org/10.5194/tc-3-195-2009 https://noa.gwlb.de/receive/cop_mods_00029950 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00029904/tc-3-195-2009.pdf https://tc.copernicus.org/articles/3/195/2009/tc-3-195-2009.pdf |
geographic |
Antarctic The Antarctic Dronning Maud Land |
geographic_facet |
Antarctic The Antarctic Dronning Maud Land |
genre |
Antarc* Antarctic Antarctica DML Dronning Maud Land EPICA greenlandic ice core Ice Sheet The Cryosphere |
genre_facet |
Antarc* Antarctic Antarctica DML Dronning Maud Land EPICA greenlandic ice core Ice Sheet The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-3-195-2009 https://noa.gwlb.de/receive/cop_mods_00029950 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00029904/tc-3-195-2009.pdf https://tc.copernicus.org/articles/3/195/2009/tc-3-195-2009.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-3-195-2009 |
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The Cryosphere |
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