Constraining variable density of ice shelves using wide-angle radar measurements
The thickness of ice shelves, a basic parameter for mass balance estimates, is typically inferred using hydrostatic equilibrium, for which knowledge of the depth-averaged density is essential. The densification from snow to ice depends on a number of local factors (e.g., temperature and surface mass...
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2016
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00013599 2023-05-15T13:34:48+02:00 Constraining variable density of ice shelves using wide-angle radar measurements Drews, Reinhard Brown, Joel Matsuoka, Kenichi Witrant, Emmanuel Philippe, Morgane Hubbard, Bryn Pattyn, Frank 2016-04 electronic https://doi.org/10.5194/tc-10-811-2016 https://noa.gwlb.de/receive/cop_mods_00013599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013555/tc-10-811-2016.pdf https://tc.copernicus.org/articles/10/811/2016/tc-10-811-2016.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-10-811-2016 https://noa.gwlb.de/receive/cop_mods_00013599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013555/tc-10-811-2016.pdf https://tc.copernicus.org/articles/10/811/2016/tc-10-811-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/tc-10-811-2016 2022-02-08T22:55:30Z The thickness of ice shelves, a basic parameter for mass balance estimates, is typically inferred using hydrostatic equilibrium, for which knowledge of the depth-averaged density is essential. The densification from snow to ice depends on a number of local factors (e.g., temperature and surface mass balance) causing spatial and temporal variations in density–depth profiles. However, direct measurements of firn density are sparse, requiring substantial logistical effort. Here, we infer density from radio-wave propagation speed using ground-based wide-angle radar data sets (10 MHz) collected at five sites on Roi Baudouin Ice Shelf (RBIS), Dronning Maud Land, Antarctica. We reconstruct depth to internal reflectors, local ice thickness, and firn-air content using a novel algorithm that includes traveltime inversion and ray tracing with a prescribed shape of the depth–density relationship. For the particular case of an ice-shelf channel, where ice thickness and surface slope change substantially over a few kilometers, the radar data suggest that firn inside the channel is about 5 % denser than outside the channel. Although this density difference is at the detection limit of the radar, it is consistent with a similar density anomaly reconstructed from optical televiewing, which reveals that the firn inside the channel is 4.7 % denser than that outside the channel. Hydrostatic ice thickness calculations used for determining basal melt rates should account for the denser firn in ice-shelf channels. The radar method presented here is robust and can easily be adapted to different radar frequencies and data-acquisition geometries. Article in Journal/Newspaper Antarc* Antarctica Dronning Maud Land Ice Shelf Ice Shelves The Cryosphere Niedersächsisches Online-Archiv NOA Dronning Maud Land Roi Baudouin ENVELOPE(24.461,24.461,-70.438,-70.438) The Cryosphere 10 2 811 823 |
institution |
Open Polar |
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Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Drews, Reinhard Brown, Joel Matsuoka, Kenichi Witrant, Emmanuel Philippe, Morgane Hubbard, Bryn Pattyn, Frank Constraining variable density of ice shelves using wide-angle radar measurements |
topic_facet |
article Verlagsveröffentlichung |
description |
The thickness of ice shelves, a basic parameter for mass balance estimates, is typically inferred using hydrostatic equilibrium, for which knowledge of the depth-averaged density is essential. The densification from snow to ice depends on a number of local factors (e.g., temperature and surface mass balance) causing spatial and temporal variations in density–depth profiles. However, direct measurements of firn density are sparse, requiring substantial logistical effort. Here, we infer density from radio-wave propagation speed using ground-based wide-angle radar data sets (10 MHz) collected at five sites on Roi Baudouin Ice Shelf (RBIS), Dronning Maud Land, Antarctica. We reconstruct depth to internal reflectors, local ice thickness, and firn-air content using a novel algorithm that includes traveltime inversion and ray tracing with a prescribed shape of the depth–density relationship. For the particular case of an ice-shelf channel, where ice thickness and surface slope change substantially over a few kilometers, the radar data suggest that firn inside the channel is about 5 % denser than outside the channel. Although this density difference is at the detection limit of the radar, it is consistent with a similar density anomaly reconstructed from optical televiewing, which reveals that the firn inside the channel is 4.7 % denser than that outside the channel. Hydrostatic ice thickness calculations used for determining basal melt rates should account for the denser firn in ice-shelf channels. The radar method presented here is robust and can easily be adapted to different radar frequencies and data-acquisition geometries. |
format |
Article in Journal/Newspaper |
author |
Drews, Reinhard Brown, Joel Matsuoka, Kenichi Witrant, Emmanuel Philippe, Morgane Hubbard, Bryn Pattyn, Frank |
author_facet |
Drews, Reinhard Brown, Joel Matsuoka, Kenichi Witrant, Emmanuel Philippe, Morgane Hubbard, Bryn Pattyn, Frank |
author_sort |
Drews, Reinhard |
title |
Constraining variable density of ice shelves using wide-angle radar measurements |
title_short |
Constraining variable density of ice shelves using wide-angle radar measurements |
title_full |
Constraining variable density of ice shelves using wide-angle radar measurements |
title_fullStr |
Constraining variable density of ice shelves using wide-angle radar measurements |
title_full_unstemmed |
Constraining variable density of ice shelves using wide-angle radar measurements |
title_sort |
constraining variable density of ice shelves using wide-angle radar measurements |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-811-2016 https://noa.gwlb.de/receive/cop_mods_00013599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013555/tc-10-811-2016.pdf https://tc.copernicus.org/articles/10/811/2016/tc-10-811-2016.pdf |
long_lat |
ENVELOPE(24.461,24.461,-70.438,-70.438) |
geographic |
Dronning Maud Land Roi Baudouin |
geographic_facet |
Dronning Maud Land Roi Baudouin |
genre |
Antarc* Antarctica Dronning Maud Land Ice Shelf Ice Shelves The Cryosphere |
genre_facet |
Antarc* Antarctica Dronning Maud Land Ice Shelf Ice Shelves 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-10-811-2016 https://noa.gwlb.de/receive/cop_mods_00013599 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00013555/tc-10-811-2016.pdf https://tc.copernicus.org/articles/10/811/2016/tc-10-811-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-10-811-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
2 |
container_start_page |
811 |
op_container_end_page |
823 |
_version_ |
1766057753490489344 |