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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ftdoajarticles:oai:doaj.org/article:3684b991640d451880452a1d9bfe001e 2023-05-15T13:46:11+02:00 Layer disturbances and the radio-echo free zone in ice sheets R. Drews O. Eisen I. Weikusat S. Kipfstuhl A. Lambrecht D. Steinhage F. Wilhelms H. Miller 2009-08-01T00:00:00Z https://doaj.org/article/3684b991640d451880452a1d9bfe001e EN eng Copernicus Publications http://www.the-cryosphere.net/3/195/2009/tc-3-195-2009.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 https://doaj.org/article/3684b991640d451880452a1d9bfe001e The Cryosphere, Vol 3, Iss 2, Pp 195-203 (2009) Environmental sciences GE1-350 Geology QE1-996.5 article 2009 ftdoajarticles 2023-01-08T01:34:56Z 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 Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic Dronning Maud Land |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 R. Drews O. Eisen I. Weikusat S. Kipfstuhl A. Lambrecht D. Steinhage F. Wilhelms H. Miller Layer disturbances and the radio-echo free zone in ice sheets |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 |
R. Drews O. Eisen I. Weikusat S. Kipfstuhl A. Lambrecht D. Steinhage F. Wilhelms H. Miller |
author_facet |
R. Drews O. Eisen I. Weikusat S. Kipfstuhl A. Lambrecht D. Steinhage F. Wilhelms H. Miller |
author_sort |
R. Drews |
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://doaj.org/article/3684b991640d451880452a1d9bfe001e |
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_source |
The Cryosphere, Vol 3, Iss 2, Pp 195-203 (2009) |
op_relation |
http://www.the-cryosphere.net/3/195/2009/tc-3-195-2009.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 https://doaj.org/article/3684b991640d451880452a1d9bfe001e |
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1766238204691742720 |