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...
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ftoregonstate:ir.library.oregonstate.edu:t148fn32v 2023-11-12T04:03:57+01:00 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 https://ir.library.oregonstate.edu/concern/articles/t148fn32v English [eng] eng American Geophysical Union https://ir.library.oregonstate.edu/concern/articles/t148fn32v Copyright Not Evaluated Article ftoregonstate 2023-10-22T16:45:49Z 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. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/jgr/journal/10.1002/%28ISSN%292169-8996/. Keywords: ice core, firn density, layering, firn, total air content, methane Article in Journal/Newspaper Antarc* Antarctic ice core Ice Sheet ScholarsArchive@OSU (Oregon State University) Antarctic West Antarctic Ice Sheet |
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ScholarsArchive@OSU (Oregon State University) |
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ftoregonstate |
language |
English |
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. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/jgr/journal/10.1002/%28ISSN%292169-8996/. Keywords: ice core, firn density, layering, firn, total air content, methane |
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 |
spellingShingle |
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 |
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 |
url |
https://ir.library.oregonstate.edu/concern/articles/t148fn32v |
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://ir.library.oregonstate.edu/concern/articles/t148fn32v |
op_rights |
Copyright Not Evaluated |
_version_ |
1782339887813361664 |