Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide
We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow...
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Format: | Article in Journal/Newspaper |
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Copernicus Publications
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00046315 2023-05-15T13:55:42+02:00 Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide Battle, M. O. Severinghaus, J. P. Sofen, E. D. Plotkin, D. Orsi, A. J. Aydin, M. Montzka, S. A. Sowers, T. Tans, P. P. 2011-11 electronic https://doi.org/10.5194/acp-11-11007-2011 https://noa.gwlb.de/receive/cop_mods_00046315 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00045935/acp-11-11007-2011.pdf https://acp.copernicus.org/articles/11/11007/2011/acp-11-11007-2011.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-11-11007-2011 https://noa.gwlb.de/receive/cop_mods_00046315 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00045935/acp-11-11007-2011.pdf https://acp.copernicus.org/articles/11/11007/2011/acp-11-11007-2011.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2011 ftnonlinearchiv https://doi.org/10.5194/acp-11-11007-2011 2022-02-08T22:39:06Z We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow firn, gravitational enrichment of heavy species throughout the diffusive column in general agreement with theoretical expectations, a ~10 m thick lock-in zone beginning at ~67 m, and a total firn thickness consistent with predictions of Kaspers et al. (2004). Our modeling work shows that the air has an age spread (spectral width) of 4.8 yr for CO2 at the firn-ice transition. We also find that advection of firn air due to the 22 cm yr−1 ice-equivalent accumulation rate has a minor impact on firn air composition, causing changes that are comparable to other modeling uncertainties and intrinsic sample variability. Furthermore, estimates of Δage (the gas age/ice age difference) at WAIS-D appear to be largely unaffected by bubble closure above the lock-in zone. Within the lock-in zone, small gas species and their isotopes show evidence of size-dependent fractionation due to permeation through the ice lattice with a size threshold of 0.36 nm, as at other sites. We also see an unequivocal and unprecedented signal of oxygen isotope fractionation within the lock-in zone, which we interpret as the mass-dependent expression of a size-dependent fractionation process. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Niedersächsisches Online-Archiv NOA Antarctic West Antarctic Ice Sheet Atmospheric Chemistry and Physics 11 21 11007 11021 |
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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 Battle, M. O. Severinghaus, J. P. Sofen, E. D. Plotkin, D. Orsi, A. J. Aydin, M. Montzka, S. A. Sowers, T. Tans, P. P. Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
topic_facet |
article Verlagsveröffentlichung |
description |
We sampled interstitial air from the perennial snowpack (firn) at a site near the West Antarctic Ice Sheet Divide (WAIS-D) and analyzed the air samples for a wide variety of gas species and their isotopes. We find limited convective influence (1.4–5.2 m, depending on detection method) in the shallow firn, gravitational enrichment of heavy species throughout the diffusive column in general agreement with theoretical expectations, a ~10 m thick lock-in zone beginning at ~67 m, and a total firn thickness consistent with predictions of Kaspers et al. (2004). Our modeling work shows that the air has an age spread (spectral width) of 4.8 yr for CO2 at the firn-ice transition. We also find that advection of firn air due to the 22 cm yr−1 ice-equivalent accumulation rate has a minor impact on firn air composition, causing changes that are comparable to other modeling uncertainties and intrinsic sample variability. Furthermore, estimates of Δage (the gas age/ice age difference) at WAIS-D appear to be largely unaffected by bubble closure above the lock-in zone. Within the lock-in zone, small gas species and their isotopes show evidence of size-dependent fractionation due to permeation through the ice lattice with a size threshold of 0.36 nm, as at other sites. We also see an unequivocal and unprecedented signal of oxygen isotope fractionation within the lock-in zone, which we interpret as the mass-dependent expression of a size-dependent fractionation process. |
format |
Article in Journal/Newspaper |
author |
Battle, M. O. Severinghaus, J. P. Sofen, E. D. Plotkin, D. Orsi, A. J. Aydin, M. Montzka, S. A. Sowers, T. Tans, P. P. |
author_facet |
Battle, M. O. Severinghaus, J. P. Sofen, E. D. Plotkin, D. Orsi, A. J. Aydin, M. Montzka, S. A. Sowers, T. Tans, P. P. |
author_sort |
Battle, M. O. |
title |
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
title_short |
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
title_full |
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
title_fullStr |
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
title_full_unstemmed |
Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide |
title_sort |
controls on the movement and composition of firn air at the west antarctic ice sheet divide |
publisher |
Copernicus Publications |
publishDate |
2011 |
url |
https://doi.org/10.5194/acp-11-11007-2011 https://noa.gwlb.de/receive/cop_mods_00046315 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00045935/acp-11-11007-2011.pdf https://acp.copernicus.org/articles/11/11007/2011/acp-11-11007-2011.pdf |
geographic |
Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-11-11007-2011 https://noa.gwlb.de/receive/cop_mods_00046315 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00045935/acp-11-11007-2011.pdf https://acp.copernicus.org/articles/11/11007/2011/acp-11-11007-2011.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-11-11007-2011 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
11 |
container_issue |
21 |
container_start_page |
11007 |
op_container_end_page |
11021 |
_version_ |
1766262499433250816 |