Archival of the water stable isotope signal in East Antarctic ice cores
The oldest ice core records are obtained from the East Antarctic plateau. Water stable isotopes records are key for reconstructions of past climatic conditions both over the ice sheet and at the evaporation source. The accuracy of such climate reconstructions crucially depends on the knowledge of al...
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ftcopernicus:oai:publications.copernicus.org:tcd55824 2023-05-15T13:54:27+02:00 Archival of the water stable isotope signal in East Antarctic ice cores Casado, Mathieu Landais, Amaelle Picard, Ghislain Münch, Thomas Laepple, Thomas Stenni, Barbara Dreossi, Giuliano Ekaykin, Alexey Arnaud, Laurent Genthon, Christophe Touzeau, Alexandra Masson-Delmotte, Valérie Jouzel, Jean 2018-09-26 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/tc-2016-263 https://tc.copernicus.org/preprints/tc-2016-263/ eng eng info:eu-repo/grantAgreement/EC/FP7/306045 doi:10.5194/tc-2016-263 https://tc.copernicus.org/preprints/tc-2016-263/ info:eu-repo/semantics/openAccess eISSN: 1994-0424 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/tc-2016-263 2020-07-20T16:23:55Z The oldest ice core records are obtained from the East Antarctic plateau. Water stable isotopes records are key for reconstructions of past climatic conditions both over the ice sheet and at the evaporation source. The accuracy of such climate reconstructions crucially depends on the knowledge of all the processes affecting the water vapour, precipitation and snow isotopic composition. Atmospheric fractionation processes are well understood and can be integrated in Rayleigh distillation and complex isotope enabled climate models. However, a comprehensive quantitative understanding of processes potentially altering the snow isotopic composition after the deposition is still missing, especially for exchanges between vapour and snow. In low accumulation sites such as found on the East Antarctic Plateau, these poorly constrained processes are especially likely to play a significant role. This limits the interpretation of isotopic composition from ice core records, specifically at short time scales. Here, we combine observations of isotopic composition in the vapour, the precipitation, the surface snow and the buried snow from various sites of the East Antarctic Plateau. At the seasonal scale, we highlight a significant impact of metamorphism on surface snow isotopic signal compared to the initial precipitation isotopic signal. In particular, in summer, exchanges of water molecules between vapour and snow are driven by the sublimation/condensation cycles at the diurnal scale. Using highly resolved isotopic composition profiles from pits in five East Antarctic sites, we identify a common 20 cm cycle which cannot be attributed to the seasonal variability of precipitation. Altogether, the smaller range of isotopic compositions observed in the buried and in the surface snow compared to the precipitation, and also the reduced slope between surface snow isotopic composition and temperature compared to precipitation, constitute evidences of post-deposition processes affecting the variability of the isotopic composition in the snow pack. To reproduce these processes in snow-models is crucial to understand the link between snow isotopic composition and climatic conditions and to improve the interpretation of isotopic composition as a paleoclimate proxy. Other/Unknown Material Antarc* Antarctic ice core Ice Sheet Copernicus Publications: E-Journals Antarctic |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The oldest ice core records are obtained from the East Antarctic plateau. Water stable isotopes records are key for reconstructions of past climatic conditions both over the ice sheet and at the evaporation source. The accuracy of such climate reconstructions crucially depends on the knowledge of all the processes affecting the water vapour, precipitation and snow isotopic composition. Atmospheric fractionation processes are well understood and can be integrated in Rayleigh distillation and complex isotope enabled climate models. However, a comprehensive quantitative understanding of processes potentially altering the snow isotopic composition after the deposition is still missing, especially for exchanges between vapour and snow. In low accumulation sites such as found on the East Antarctic Plateau, these poorly constrained processes are especially likely to play a significant role. This limits the interpretation of isotopic composition from ice core records, specifically at short time scales. Here, we combine observations of isotopic composition in the vapour, the precipitation, the surface snow and the buried snow from various sites of the East Antarctic Plateau. At the seasonal scale, we highlight a significant impact of metamorphism on surface snow isotopic signal compared to the initial precipitation isotopic signal. In particular, in summer, exchanges of water molecules between vapour and snow are driven by the sublimation/condensation cycles at the diurnal scale. Using highly resolved isotopic composition profiles from pits in five East Antarctic sites, we identify a common 20 cm cycle which cannot be attributed to the seasonal variability of precipitation. Altogether, the smaller range of isotopic compositions observed in the buried and in the surface snow compared to the precipitation, and also the reduced slope between surface snow isotopic composition and temperature compared to precipitation, constitute evidences of post-deposition processes affecting the variability of the isotopic composition in the snow pack. To reproduce these processes in snow-models is crucial to understand the link between snow isotopic composition and climatic conditions and to improve the interpretation of isotopic composition as a paleoclimate proxy. |
format |
Other/Unknown Material |
author |
Casado, Mathieu Landais, Amaelle Picard, Ghislain Münch, Thomas Laepple, Thomas Stenni, Barbara Dreossi, Giuliano Ekaykin, Alexey Arnaud, Laurent Genthon, Christophe Touzeau, Alexandra Masson-Delmotte, Valérie Jouzel, Jean |
spellingShingle |
Casado, Mathieu Landais, Amaelle Picard, Ghislain Münch, Thomas Laepple, Thomas Stenni, Barbara Dreossi, Giuliano Ekaykin, Alexey Arnaud, Laurent Genthon, Christophe Touzeau, Alexandra Masson-Delmotte, Valérie Jouzel, Jean Archival of the water stable isotope signal in East Antarctic ice cores |
author_facet |
Casado, Mathieu Landais, Amaelle Picard, Ghislain Münch, Thomas Laepple, Thomas Stenni, Barbara Dreossi, Giuliano Ekaykin, Alexey Arnaud, Laurent Genthon, Christophe Touzeau, Alexandra Masson-Delmotte, Valérie Jouzel, Jean |
author_sort |
Casado, Mathieu |
title |
Archival of the water stable isotope signal in East Antarctic ice cores |
title_short |
Archival of the water stable isotope signal in East Antarctic ice cores |
title_full |
Archival of the water stable isotope signal in East Antarctic ice cores |
title_fullStr |
Archival of the water stable isotope signal in East Antarctic ice cores |
title_full_unstemmed |
Archival of the water stable isotope signal in East Antarctic ice cores |
title_sort |
archival of the water stable isotope signal in east antarctic ice cores |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-2016-263 https://tc.copernicus.org/preprints/tc-2016-263/ |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core Ice Sheet |
genre_facet |
Antarc* Antarctic ice core Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/306045 doi:10.5194/tc-2016-263 https://tc.copernicus.org/preprints/tc-2016-263/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-2016-263 |
_version_ |
1766260330707550208 |