Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core
In the framework of the International Partnerships in Ice Core Sciences, one of the most important targets is to retrieve an Antarctic ice core that extends over the last 1.5 million years (i.e. an ice core that enters the climate era when glacial–interglacial cycles followed the obliquity cycles of...
Published in: | The Cryosphere |
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Language: | English |
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Copernicus Publications
2014
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00020569 2023-05-15T13:41:02+02:00 Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core Bereiter, B. Fischer, H. Schwander, J. Stocker, T. F. 2014-02 electronic https://doi.org/10.5194/tc-8-245-2014 https://noa.gwlb.de/receive/cop_mods_00020569 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020524/tc-8-245-2014.pdf https://tc.copernicus.org/articles/8/245/2014/tc-8-245-2014.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-8-245-2014 https://noa.gwlb.de/receive/cop_mods_00020569 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020524/tc-8-245-2014.pdf https://tc.copernicus.org/articles/8/245/2014/tc-8-245-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/tc-8-245-2014 2022-02-08T22:52:06Z In the framework of the International Partnerships in Ice Core Sciences, one of the most important targets is to retrieve an Antarctic ice core that extends over the last 1.5 million years (i.e. an ice core that enters the climate era when glacial–interglacial cycles followed the obliquity cycles of the earth). In such an ice core the annual layers of the oldest ice would be thinned by a factor of about 100 and the climatic information of a 10 000 yr interval would be contained in less than 1 m of ice. The gas record in such an Antarctic ice core can potentially reveal the role of greenhouse gas forcing on these 40 000 yr cycles. However, besides the extreme thinning of the annual layers, also the long residence time of the trapped air in the ice and the relatively high ice temperatures near the bedrock favour diffusive exchanges. To investigate the changes in the O2 / N2 ratio, as well as the trapped CO2 concentrations, we modelled the diffusive exchange of the trapped gases O2, N2 and CO2 along the vertical axis. However, the boundary conditions of a potential drilling site are not yet well constrained and the uncertainties in the permeation coefficients of the air constituents in the ice are large. In our simulations, we have set the drill site ice thickness at 2700 m and the bedrock ice temperature at 5–10 K below the ice pressure melting point. Using these conditions and including all further uncertainties associated with the drill site and the permeation coefficients, the results suggest that in the oldest ice the precessional variations in the O2 / N2 ratio will be damped by 50–100%, whereas CO2 concentration changes associated with glacial–interglacial variations will likely be conserved (simulated damping 5%). If the precessional O2 / N2 signal will have disappeared completely in this future ice core, orbital tuning of the ice-core age scale will be limited. Article in Journal/Newspaper Antarc* Antarctic ice core The Cryosphere Niedersächsisches Online-Archiv NOA Antarctic The Cryosphere 8 1 245 256 |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Bereiter, B. Fischer, H. Schwander, J. Stocker, T. F. Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
topic_facet |
article Verlagsveröffentlichung |
description |
In the framework of the International Partnerships in Ice Core Sciences, one of the most important targets is to retrieve an Antarctic ice core that extends over the last 1.5 million years (i.e. an ice core that enters the climate era when glacial–interglacial cycles followed the obliquity cycles of the earth). In such an ice core the annual layers of the oldest ice would be thinned by a factor of about 100 and the climatic information of a 10 000 yr interval would be contained in less than 1 m of ice. The gas record in such an Antarctic ice core can potentially reveal the role of greenhouse gas forcing on these 40 000 yr cycles. However, besides the extreme thinning of the annual layers, also the long residence time of the trapped air in the ice and the relatively high ice temperatures near the bedrock favour diffusive exchanges. To investigate the changes in the O2 / N2 ratio, as well as the trapped CO2 concentrations, we modelled the diffusive exchange of the trapped gases O2, N2 and CO2 along the vertical axis. However, the boundary conditions of a potential drilling site are not yet well constrained and the uncertainties in the permeation coefficients of the air constituents in the ice are large. In our simulations, we have set the drill site ice thickness at 2700 m and the bedrock ice temperature at 5–10 K below the ice pressure melting point. Using these conditions and including all further uncertainties associated with the drill site and the permeation coefficients, the results suggest that in the oldest ice the precessional variations in the O2 / N2 ratio will be damped by 50–100%, whereas CO2 concentration changes associated with glacial–interglacial variations will likely be conserved (simulated damping 5%). If the precessional O2 / N2 signal will have disappeared completely in this future ice core, orbital tuning of the ice-core age scale will be limited. |
format |
Article in Journal/Newspaper |
author |
Bereiter, B. Fischer, H. Schwander, J. Stocker, T. F. |
author_facet |
Bereiter, B. Fischer, H. Schwander, J. Stocker, T. F. |
author_sort |
Bereiter, B. |
title |
Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
title_short |
Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
title_full |
Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
title_fullStr |
Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
title_full_unstemmed |
Diffusive equilibration of N2, O2 and CO2 mixing ratios in a 1.5-million-years-old ice core |
title_sort |
diffusive equilibration of n2, o2 and co2 mixing ratios in a 1.5-million-years-old ice core |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/tc-8-245-2014 https://noa.gwlb.de/receive/cop_mods_00020569 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020524/tc-8-245-2014.pdf https://tc.copernicus.org/articles/8/245/2014/tc-8-245-2014.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core The Cryosphere |
genre_facet |
Antarc* Antarctic ice core 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-8-245-2014 https://noa.gwlb.de/receive/cop_mods_00020569 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020524/tc-8-245-2014.pdf https://tc.copernicus.org/articles/8/245/2014/tc-8-245-2014.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-8-245-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
1 |
container_start_page |
245 |
op_container_end_page |
256 |
_version_ |
1766144799186878464 |