Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling
Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock,...
Published in: | The Cryosphere |
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Copernicus Publications
2017
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00008684 2023-05-15T13:34:49+02:00 Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling Passalacqua, Olivier Ritz, Catherine Parrenin, Frédéric Urbini, Stefano Frezzotti, Massimo 2017-09 electronic https://doi.org/10.5194/tc-11-2231-2017 https://noa.gwlb.de/receive/cop_mods_00008684 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00008641/tc-11-2231-2017.pdf https://tc.copernicus.org/articles/11/2231/2017/tc-11-2231-2017.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-11-2231-2017 https://noa.gwlb.de/receive/cop_mods_00008684 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00008641/tc-11-2231-2017.pdf https://tc.copernicus.org/articles/11/2231/2017/tc-11-2231-2017.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2017 ftnonlinearchiv https://doi.org/10.5194/tc-11-2231-2017 2022-02-08T22:57:56Z Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice–bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km × 130 km area, with a N–S gradient and with values ranging from 48 to 60 mW m−2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet The Cryosphere Niedersächsisches Online-Archiv NOA Antarctic East Antarctic Ice Sheet The Cryosphere 11 5 2231 2246 |
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Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Passalacqua, Olivier Ritz, Catherine Parrenin, Frédéric Urbini, Stefano Frezzotti, Massimo Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
topic_facet |
article Verlagsveröffentlichung |
description |
Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice–bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km × 130 km area, with a N–S gradient and with values ranging from 48 to 60 mW m−2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF. |
format |
Article in Journal/Newspaper |
author |
Passalacqua, Olivier Ritz, Catherine Parrenin, Frédéric Urbini, Stefano Frezzotti, Massimo |
author_facet |
Passalacqua, Olivier Ritz, Catherine Parrenin, Frédéric Urbini, Stefano Frezzotti, Massimo |
author_sort |
Passalacqua, Olivier |
title |
Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
title_short |
Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
title_full |
Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
title_fullStr |
Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
title_full_unstemmed |
Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
title_sort |
geothermal flux and basal melt rate in the dome c region inferred from radar reflectivity and heat modelling |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/tc-11-2231-2017 https://noa.gwlb.de/receive/cop_mods_00008684 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00008641/tc-11-2231-2017.pdf https://tc.copernicus.org/articles/11/2231/2017/tc-11-2231-2017.pdf |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet The Cryosphere |
genre_facet |
Antarc* Antarctic 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-11-2231-2017 https://noa.gwlb.de/receive/cop_mods_00008684 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00008641/tc-11-2231-2017.pdf https://tc.copernicus.org/articles/11/2231/2017/tc-11-2231-2017.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-11-2231-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
5 |
container_start_page |
2231 |
op_container_end_page |
2246 |
_version_ |
1766058000624123904 |