Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica
Physical features preserved in ice cores may provide unique records about past atmospheric variability. Linking the formation and preservation of these features and the atmospheric processes causing them is key to their interpretation as palaeoclimate proxies. We imaged ice cores from Law Dome, East...
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ftcopernicus:oai:publications.copernicus.org:egusphere110509 2024-01-07T09:38:54+01:00 Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica Zhang, Lingwei Vance, Tessa R. Fraser, Alexander D. Jong, Lenneke M. Thompson, Sarah S. Criscitiello, Alison S. Abram, Nerilie J. 2023-12-06 application/pdf https://doi.org/10.5194/egusphere-2023-611 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-611/ eng eng doi:10.5194/egusphere-2023-611 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-611/ eISSN: Text 2023 ftcopernicus https://doi.org/10.5194/egusphere-2023-611 2023-12-11T17:24:19Z Physical features preserved in ice cores may provide unique records about past atmospheric variability. Linking the formation and preservation of these features and the atmospheric processes causing them is key to their interpretation as palaeoclimate proxies. We imaged ice cores from Law Dome, East Antarctica, using an intermediate layer core scanner (ILCS) and found that thin bubble-free layers (BFLs) occur multiple times per year at this site. The origin of these features is unknown. We used a previously developed age–depth scale in conjunction with regional accumulation estimated from atmospheric reanalysis data (ERA5) to estimate the year and month that the BFLs occurred, and then we performed seasonal and annual analysis to reduce the overall dating errors. We then investigated measurements of snow surface height from a co-located automatic weather station to determine snow surface features co-occurring with BFLs, as well as their estimated occurrence date. We also used ERA5 to investigate potentially relevant local/regional atmospheric processes (temperature inversions, wind scour, accumulation hiatuses and extreme precipitation) associated with BFL occurrence. Finally, we used a synoptic typing dataset of the southern Indian and southwest Pacific oceans to investigate the relationship between large-scale atmospheric patterns and BFL occurrence. Our results show that BFLs occur (1) primarily in autumn and winter, (2) in conjunction with accumulation hiatuses > 4 d, and (3) during synoptic patterns characterised by meridional atmospheric flow related to the episodic blocking and channelling of maritime moisture to the ice core site. Thus, BFLs may act as a seasonal marker (autumn/winter) and may indicate episodic changes in accumulation (such as hiatuses) associated with large-scale circulation. This study provides a pathway to the development of a new proxy for past climate in the Law Dome ice cores, specifically past snowfall conditions relating to synoptic variability over the southern Indian Ocean. Text Antarc* Antarctica East Antarctica ice core Copernicus Publications: E-Journals East Antarctica Indian Law Dome ENVELOPE(112.833,112.833,-66.733,-66.733) Pacific |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Physical features preserved in ice cores may provide unique records about past atmospheric variability. Linking the formation and preservation of these features and the atmospheric processes causing them is key to their interpretation as palaeoclimate proxies. We imaged ice cores from Law Dome, East Antarctica, using an intermediate layer core scanner (ILCS) and found that thin bubble-free layers (BFLs) occur multiple times per year at this site. The origin of these features is unknown. We used a previously developed age–depth scale in conjunction with regional accumulation estimated from atmospheric reanalysis data (ERA5) to estimate the year and month that the BFLs occurred, and then we performed seasonal and annual analysis to reduce the overall dating errors. We then investigated measurements of snow surface height from a co-located automatic weather station to determine snow surface features co-occurring with BFLs, as well as their estimated occurrence date. We also used ERA5 to investigate potentially relevant local/regional atmospheric processes (temperature inversions, wind scour, accumulation hiatuses and extreme precipitation) associated with BFL occurrence. Finally, we used a synoptic typing dataset of the southern Indian and southwest Pacific oceans to investigate the relationship between large-scale atmospheric patterns and BFL occurrence. Our results show that BFLs occur (1) primarily in autumn and winter, (2) in conjunction with accumulation hiatuses > 4 d, and (3) during synoptic patterns characterised by meridional atmospheric flow related to the episodic blocking and channelling of maritime moisture to the ice core site. Thus, BFLs may act as a seasonal marker (autumn/winter) and may indicate episodic changes in accumulation (such as hiatuses) associated with large-scale circulation. This study provides a pathway to the development of a new proxy for past climate in the Law Dome ice cores, specifically past snowfall conditions relating to synoptic variability over the southern Indian Ocean. |
format |
Text |
author |
Zhang, Lingwei Vance, Tessa R. Fraser, Alexander D. Jong, Lenneke M. Thompson, Sarah S. Criscitiello, Alison S. Abram, Nerilie J. |
spellingShingle |
Zhang, Lingwei Vance, Tessa R. Fraser, Alexander D. Jong, Lenneke M. Thompson, Sarah S. Criscitiello, Alison S. Abram, Nerilie J. Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
author_facet |
Zhang, Lingwei Vance, Tessa R. Fraser, Alexander D. Jong, Lenneke M. Thompson, Sarah S. Criscitiello, Alison S. Abram, Nerilie J. |
author_sort |
Zhang, Lingwei |
title |
Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
title_short |
Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
title_full |
Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
title_fullStr |
Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
title_full_unstemmed |
Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica |
title_sort |
identifying atmospheric processes favouring the formation of bubble free layers in law dome ice core, east antarctica |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-611 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-611/ |
long_lat |
ENVELOPE(112.833,112.833,-66.733,-66.733) |
geographic |
East Antarctica Indian Law Dome Pacific |
geographic_facet |
East Antarctica Indian Law Dome Pacific |
genre |
Antarc* Antarctica East Antarctica ice core |
genre_facet |
Antarc* Antarctica East Antarctica ice core |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2023-611 https://egusphere.copernicus.org/preprints/2023/egusphere-2023-611/ |
op_doi |
https://doi.org/10.5194/egusphere-2023-611 |
_version_ |
1787426877653123072 |