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,...
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ftunivroma3iris:oai:iris.uniroma3.it:11590/353559 2024-02-27T08:34:58+00:00 Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling Passalacqua O. Ritz C. Parrenin F. Urbini S. Frezzotti M. Passalacqua, O. Ritz, C. Parrenin, F. Urbini, S. Frezzotti, M. 2017 http://hdl.handle.net/11590/353559 https://doi.org/10.5194/tc-11-2231-2017 http://www.the-cryosphere.net/volumes_and_issues.html eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000411259100001 volume:11 issue:5 firstpage:2231 lastpage:2246 numberofpages:16 journal:THE CRYOSPHERE http://hdl.handle.net/11590/353559 doi:10.5194/tc-11-2231-2017 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85029756632 http://www.the-cryosphere.net/volumes_and_issues.html info:eu-repo/semantics/article 2017 ftunivroma3iris https://doi.org/10.5194/tc-11-2231-2017 2024-01-31T17:41:13Z 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 800ĝ€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 80g 130km area, with a N-S gradient and with values ranging from 48 to 60g2. 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 Anagrafe della Ricerca d'Ateneo (Universitá degli studi Roma Tre) Antarctic East Antarctic Ice Sheet The Cryosphere 11 5 2231 2246 |
institution |
Open Polar |
collection |
Anagrafe della Ricerca d'Ateneo (Universitá degli studi Roma Tre) |
op_collection_id |
ftunivroma3iris |
language |
English |
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 800ĝ€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 80g 130km area, with a N-S gradient and with values ranging from 48 to 60g2. 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. |
author2 |
Passalacqua, O. Ritz, C. Parrenin, F. Urbini, S. Frezzotti, M. |
format |
Article in Journal/Newspaper |
author |
Passalacqua O. Ritz C. Parrenin F. Urbini S. Frezzotti M. |
spellingShingle |
Passalacqua O. Ritz C. Parrenin F. Urbini S. Frezzotti M. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling |
author_facet |
Passalacqua O. Ritz C. Parrenin F. Urbini S. Frezzotti M. |
author_sort |
Passalacqua O. |
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 |
publishDate |
2017 |
url |
http://hdl.handle.net/11590/353559 https://doi.org/10.5194/tc-11-2231-2017 http://www.the-cryosphere.net/volumes_and_issues.html |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000411259100001 volume:11 issue:5 firstpage:2231 lastpage:2246 numberofpages:16 journal:THE CRYOSPHERE http://hdl.handle.net/11590/353559 doi:10.5194/tc-11-2231-2017 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85029756632 http://www.the-cryosphere.net/volumes_and_issues.html |
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 |
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1792041349084610560 |