Observing and modeling the influence of layering on bubble trapping in polar firn
Interpretation of ice core trace gas records depends on an accurate understanding of the processes that smooth the atmospheric signal in the firn. Much work has been done to understand the processes affecting air transport in the open pores of the firn, but a paucity of data from air trapped in bubb...
Published in: | Journal of Geophysical Research: Atmospheres |
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Format: | Article in Journal/Newspaper |
Language: | English |
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American Geophysical Union
2015
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/37619/ https://doi.org/10.1002/2014JD022766 https://nrl.northumbria.ac.uk/id/eprint/37619/1/Mitchell_et_al-2015-Journal_of_Geophysical_Research__Atmospheres%20%281%29.pdf |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:37619 2023-05-15T13:56:54+02:00 Observing and modeling the influence of layering on bubble trapping in polar firn Mitchell, Logan E. Buizert, Christo Brook, Edward J. Breton, Daniel J. Fegyveresi, John Baggenstos, Daniel Orsi, Anais Severinghaus, Jeffrey Alley, Richard B. Albert, Mary Rhodes, Rachael H. McConnell, Joseph R. Sigl, Michael Maselli, Olivia Gregory, Stephanie Ahn, Jinho 2015-03-27 text https://nrl.northumbria.ac.uk/id/eprint/37619/ https://doi.org/10.1002/2014JD022766 https://nrl.northumbria.ac.uk/id/eprint/37619/1/Mitchell_et_al-2015-Journal_of_Geophysical_Research__Atmospheres%20%281%29.pdf en eng American Geophysical Union https://nrl.northumbria.ac.uk/id/eprint/37619/1/Mitchell_et_al-2015-Journal_of_Geophysical_Research__Atmospheres%20%281%29.pdf Mitchell, Logan E., Buizert, Christo, Brook, Edward J., Breton, Daniel J., Fegyveresi, John, Baggenstos, Daniel, Orsi, Anais, Severinghaus, Jeffrey, Alley, Richard B., Albert, Mary, Rhodes, Rachael H., McConnell, Joseph R., Sigl, Michael, Maselli, Olivia, Gregory, Stephanie and Ahn, Jinho (2015) Observing and modeling the influence of layering on bubble trapping in polar firn. Journal of Geophysical Research: Atmospheres, 120 (6). pp. 2558-2574. ISSN 2169-897X F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2015 ftunivnorthumb https://doi.org/10.1002/2014JD022766 2022-09-25T06:08:59Z Interpretation of ice core trace gas records depends on an accurate understanding of the processes that smooth the atmospheric signal in the firn. Much work has been done to understand the processes affecting air transport in the open pores of the firn, but a paucity of data from air trapped in bubbles in the firn‐ice transition region has limited the ability to constrain the effect of bubble closure processes. Here we present high‐resolution measurements of firn density, methane concentrations, nitrogen isotopes, and total air content that show layering in the firn‐ice transition region at the West Antarctic Ice Sheet (WAIS) Divide ice core site. Using the notion that bubble trapping is a stochastic process, we derive a new parameterization for closed porosity that incorporates the effects of layering in a steady state firn modeling approach. We include the process of bubble trapping into an open‐porosity firn air transport model and obtain a good fit to the firn core data. We find that layering broadens the depth range over which bubbles are trapped, widens the modeled gas age distribution of air in closed bubbles, reduces the mean gas age of air in closed bubbles, and introduces stratigraphic irregularities in the gas age scale that have a peak‐to‐peak variability of ~10 years at WAIS Divide. For a more complete understanding of gas occlusion and its impact on ice core records, we suggest that this experiment be repeated at sites climatically different from WAIS Divide, for example, on the East Antarctic plateau. Article in Journal/Newspaper Antarc* Antarctic ice core Ice Sheet Northumbria University, Newcastle: Northumbria Research Link (NRL) Antarctic West Antarctic Ice Sheet Journal of Geophysical Research: Atmospheres 120 6 2558 2574 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Mitchell, Logan E. Buizert, Christo Brook, Edward J. Breton, Daniel J. Fegyveresi, John Baggenstos, Daniel Orsi, Anais Severinghaus, Jeffrey Alley, Richard B. Albert, Mary Rhodes, Rachael H. McConnell, Joseph R. Sigl, Michael Maselli, Olivia Gregory, Stephanie Ahn, Jinho Observing and modeling the influence of layering on bubble trapping in polar firn |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
Interpretation of ice core trace gas records depends on an accurate understanding of the processes that smooth the atmospheric signal in the firn. Much work has been done to understand the processes affecting air transport in the open pores of the firn, but a paucity of data from air trapped in bubbles in the firn‐ice transition region has limited the ability to constrain the effect of bubble closure processes. Here we present high‐resolution measurements of firn density, methane concentrations, nitrogen isotopes, and total air content that show layering in the firn‐ice transition region at the West Antarctic Ice Sheet (WAIS) Divide ice core site. Using the notion that bubble trapping is a stochastic process, we derive a new parameterization for closed porosity that incorporates the effects of layering in a steady state firn modeling approach. We include the process of bubble trapping into an open‐porosity firn air transport model and obtain a good fit to the firn core data. We find that layering broadens the depth range over which bubbles are trapped, widens the modeled gas age distribution of air in closed bubbles, reduces the mean gas age of air in closed bubbles, and introduces stratigraphic irregularities in the gas age scale that have a peak‐to‐peak variability of ~10 years at WAIS Divide. For a more complete understanding of gas occlusion and its impact on ice core records, we suggest that this experiment be repeated at sites climatically different from WAIS Divide, for example, on the East Antarctic plateau. |
format |
Article in Journal/Newspaper |
author |
Mitchell, Logan E. Buizert, Christo Brook, Edward J. Breton, Daniel J. Fegyveresi, John Baggenstos, Daniel Orsi, Anais Severinghaus, Jeffrey Alley, Richard B. Albert, Mary Rhodes, Rachael H. McConnell, Joseph R. Sigl, Michael Maselli, Olivia Gregory, Stephanie Ahn, Jinho |
author_facet |
Mitchell, Logan E. Buizert, Christo Brook, Edward J. Breton, Daniel J. Fegyveresi, John Baggenstos, Daniel Orsi, Anais Severinghaus, Jeffrey Alley, Richard B. Albert, Mary Rhodes, Rachael H. McConnell, Joseph R. Sigl, Michael Maselli, Olivia Gregory, Stephanie Ahn, Jinho |
author_sort |
Mitchell, Logan E. |
title |
Observing and modeling the influence of layering on bubble trapping in polar firn |
title_short |
Observing and modeling the influence of layering on bubble trapping in polar firn |
title_full |
Observing and modeling the influence of layering on bubble trapping in polar firn |
title_fullStr |
Observing and modeling the influence of layering on bubble trapping in polar firn |
title_full_unstemmed |
Observing and modeling the influence of layering on bubble trapping in polar firn |
title_sort |
observing and modeling the influence of layering on bubble trapping in polar firn |
publisher |
American Geophysical Union |
publishDate |
2015 |
url |
https://nrl.northumbria.ac.uk/id/eprint/37619/ https://doi.org/10.1002/2014JD022766 https://nrl.northumbria.ac.uk/id/eprint/37619/1/Mitchell_et_al-2015-Journal_of_Geophysical_Research__Atmospheres%20%281%29.pdf |
geographic |
Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic ice core Ice Sheet |
genre_facet |
Antarc* Antarctic ice core Ice Sheet |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/37619/1/Mitchell_et_al-2015-Journal_of_Geophysical_Research__Atmospheres%20%281%29.pdf Mitchell, Logan E., Buizert, Christo, Brook, Edward J., Breton, Daniel J., Fegyveresi, John, Baggenstos, Daniel, Orsi, Anais, Severinghaus, Jeffrey, Alley, Richard B., Albert, Mary, Rhodes, Rachael H., McConnell, Joseph R., Sigl, Michael, Maselli, Olivia, Gregory, Stephanie and Ahn, Jinho (2015) Observing and modeling the influence of layering on bubble trapping in polar firn. Journal of Geophysical Research: Atmospheres, 120 (6). pp. 2558-2574. ISSN 2169-897X |
op_doi |
https://doi.org/10.1002/2014JD022766 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
120 |
container_issue |
6 |
container_start_page |
2558 |
op_container_end_page |
2574 |
_version_ |
1766264502729310208 |