Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations
Water stable isotopes recorded in Antarctic ice cores have traditionally been used to infer past surface air temperatures (SAT). During the historical period (1850 onward), observational data and good quality ice core records overlap, yielding an opportunity to investigate key relationships between...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00070330 2024-01-07T09:39:19+01:00 Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations Oger, Sentia Sime, Louise Holloway, Max 2023-12 electronic https://doi.org/10.5194/egusphere-2023-2735 https://noa.gwlb.de/receive/cop_mods_00070330 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068683/egusphere-2023-2735.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2735/egusphere-2023-2735.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2023-2735 https://noa.gwlb.de/receive/cop_mods_00070330 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068683/egusphere-2023-2735.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2735/egusphere-2023-2735.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/egusphere-2023-2735 2023-12-11T00:22:45Z Water stable isotopes recorded in Antarctic ice cores have traditionally been used to infer past surface air temperatures (SAT). During the historical period (1850 onward), observational data and good quality ice core records overlap, yielding an opportunity to investigate key relationships between ice core stable water isotope (δ18O) measurements and the Antarctic climate. We present a new ensemble of climate model simulations covering 1851–2004 using the UK Met Office HadCM3 general circulation model equipped with water stable isotopes. Our ensemble captures observed historical SAT and precipitation trends, and weak δ18O trends. The weak δ18O trends mean there is no significant relationship between SAT and δ18O over one third of Antarctica, and also half of our considered ice core sites, though relationships are stronger when using regional averages. The strongest regional relationships occur in the West Antarctic Ice Sheet (WAIS) region. This decoupling between SAT and δ18O occurs primarily because of the impact of autumnal sea ice loss during the simulated warming. The warming and sea ice loss is associated with: (i) changes in near-coastal air mass intrusions (synoptic effects) induced by changes in the large-scale circulation and/or sea ice; (ii) direct sea ice driven changes in moisture pathways (especially lengths) to Antarctica; and (iii) precipitation seasonality changes, again mostly driven by sea ice changes. Consequently when reconstructing temperatures over these timescales, changes in sea ice need to be considered; both to determine the most appropriate SAT and δ18O relationship, and to understand how uncertainties affect the inference of past temperature from ice cores δ18O measurements. Article in Journal/Newspaper Antarc* Antarctic Antarctica ice core Ice Sheet Sea ice Niedersächsisches Online-Archiv NOA Antarctic The Antarctic West Antarctic Ice Sheet |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Oger, Sentia Sime, Louise Holloway, Max Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
topic_facet |
article Verlagsveröffentlichung |
description |
Water stable isotopes recorded in Antarctic ice cores have traditionally been used to infer past surface air temperatures (SAT). During the historical period (1850 onward), observational data and good quality ice core records overlap, yielding an opportunity to investigate key relationships between ice core stable water isotope (δ18O) measurements and the Antarctic climate. We present a new ensemble of climate model simulations covering 1851–2004 using the UK Met Office HadCM3 general circulation model equipped with water stable isotopes. Our ensemble captures observed historical SAT and precipitation trends, and weak δ18O trends. The weak δ18O trends mean there is no significant relationship between SAT and δ18O over one third of Antarctica, and also half of our considered ice core sites, though relationships are stronger when using regional averages. The strongest regional relationships occur in the West Antarctic Ice Sheet (WAIS) region. This decoupling between SAT and δ18O occurs primarily because of the impact of autumnal sea ice loss during the simulated warming. The warming and sea ice loss is associated with: (i) changes in near-coastal air mass intrusions (synoptic effects) induced by changes in the large-scale circulation and/or sea ice; (ii) direct sea ice driven changes in moisture pathways (especially lengths) to Antarctica; and (iii) precipitation seasonality changes, again mostly driven by sea ice changes. Consequently when reconstructing temperatures over these timescales, changes in sea ice need to be considered; both to determine the most appropriate SAT and δ18O relationship, and to understand how uncertainties affect the inference of past temperature from ice cores δ18O measurements. |
format |
Article in Journal/Newspaper |
author |
Oger, Sentia Sime, Louise Holloway, Max |
author_facet |
Oger, Sentia Sime, Louise Holloway, Max |
author_sort |
Oger, Sentia |
title |
Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
title_short |
Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
title_full |
Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
title_fullStr |
Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
title_full_unstemmed |
Decoupling of δ18O from surface temperature in Antarctica in an ensemble of Historical simulations |
title_sort |
decoupling of δ18o from surface temperature in antarctica in an ensemble of historical simulations |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-2735 https://noa.gwlb.de/receive/cop_mods_00070330 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068683/egusphere-2023-2735.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2735/egusphere-2023-2735.pdf |
geographic |
Antarctic The Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic The Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica ice core Ice Sheet Sea ice |
genre_facet |
Antarc* Antarctic Antarctica ice core Ice Sheet Sea ice |
op_relation |
https://doi.org/10.5194/egusphere-2023-2735 https://noa.gwlb.de/receive/cop_mods_00070330 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068683/egusphere-2023-2735.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2735/egusphere-2023-2735.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/egusphere-2023-2735 |
_version_ |
1787429520420110336 |