Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study
Atmospheric information embedded in ice-core nitrate is disturbed by post-depositional processing. Here we used a layered snow photochemical column model to explicitly investigate the effects of post-depositional processing on snow nitrate and its isotopes ( δ 15 N and Δ 17 O ) at Summit, Greenland,...
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Online Access: | https://doi.org/10.5194/tc-15-4207-2021 https://tc.copernicus.org/articles/15/4207/2021/ |
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ftcopernicus:oai:publications.copernicus.org:tc93494 2023-05-15T16:28:16+02:00 Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study Jiang, Zhuang Alexander, Becky Savarino, Joel Erbland, Joseph Geng, Lei 2021-09-03 application/pdf https://doi.org/10.5194/tc-15-4207-2021 https://tc.copernicus.org/articles/15/4207/2021/ eng eng doi:10.5194/tc-15-4207-2021 https://tc.copernicus.org/articles/15/4207/2021/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-15-4207-2021 2021-09-06T16:22:27Z Atmospheric information embedded in ice-core nitrate is disturbed by post-depositional processing. Here we used a layered snow photochemical column model to explicitly investigate the effects of post-depositional processing on snow nitrate and its isotopes ( δ 15 N and Δ 17 O ) at Summit, Greenland, where post-depositional processing was thought to be minimal due to the high snow accumulation rate. We found significant redistribution of nitrate in the upper snowpack through photolysis, and up to 21 % of nitrate was lost and/or redistributed after deposition. The model indicates post-depositional processing can reproduce much of the observed δ 15 N seasonality, while seasonal variations in δ 15 N of primary nitrate are needed to reconcile the timing of the lowest seasonal δ 15 N . In contrast, post-depositional processing can only induce less than 2.1 ‰ seasonal Δ 17 O change, much smaller than the observation (9 ‰ ) that is ultimately determined by seasonal differences in nitrate formation pathway. Despite significant redistribution of snow nitrate in the photic zone and the associated effects on δ 15 N seasonality, the net annual effect of post-depositional processing is relatively small, suggesting preservation of atmospheric signals at the annual scale under the present Summit conditions. But at longer timescales when large changes in snow accumulation rate occur this post-depositional processing could become a major driver of the δ 15 N variability in ice-core nitrate. Text Greenland ice core Copernicus Publications: E-Journals Greenland The Cryosphere 15 9 4207 4220 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Atmospheric information embedded in ice-core nitrate is disturbed by post-depositional processing. Here we used a layered snow photochemical column model to explicitly investigate the effects of post-depositional processing on snow nitrate and its isotopes ( δ 15 N and Δ 17 O ) at Summit, Greenland, where post-depositional processing was thought to be minimal due to the high snow accumulation rate. We found significant redistribution of nitrate in the upper snowpack through photolysis, and up to 21 % of nitrate was lost and/or redistributed after deposition. The model indicates post-depositional processing can reproduce much of the observed δ 15 N seasonality, while seasonal variations in δ 15 N of primary nitrate are needed to reconcile the timing of the lowest seasonal δ 15 N . In contrast, post-depositional processing can only induce less than 2.1 ‰ seasonal Δ 17 O change, much smaller than the observation (9 ‰ ) that is ultimately determined by seasonal differences in nitrate formation pathway. Despite significant redistribution of snow nitrate in the photic zone and the associated effects on δ 15 N seasonality, the net annual effect of post-depositional processing is relatively small, suggesting preservation of atmospheric signals at the annual scale under the present Summit conditions. But at longer timescales when large changes in snow accumulation rate occur this post-depositional processing could become a major driver of the δ 15 N variability in ice-core nitrate. |
format |
Text |
author |
Jiang, Zhuang Alexander, Becky Savarino, Joel Erbland, Joseph Geng, Lei |
spellingShingle |
Jiang, Zhuang Alexander, Becky Savarino, Joel Erbland, Joseph Geng, Lei Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
author_facet |
Jiang, Zhuang Alexander, Becky Savarino, Joel Erbland, Joseph Geng, Lei |
author_sort |
Jiang, Zhuang |
title |
Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
title_short |
Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
title_full |
Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
title_fullStr |
Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
title_full_unstemmed |
Impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at Summit, Greenland: a model-based study |
title_sort |
impacts of the photo-driven post-depositional processing on snow nitrate and its isotopes at summit, greenland: a model-based study |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-4207-2021 https://tc.copernicus.org/articles/15/4207/2021/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland ice core |
genre_facet |
Greenland ice core |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-15-4207-2021 https://tc.copernicus.org/articles/15/4207/2021/ |
op_doi |
https://doi.org/10.5194/tc-15-4207-2021 |
container_title |
The Cryosphere |
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15 |
container_issue |
9 |
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4207 |
op_container_end_page |
4220 |
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1766017899672109056 |