Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities
International audience The transformation of snow into ice is a complex phenomenon that is difficult to model. Depending on surface temperature and accumulation rate, it may take several decades to millennia for air to be entrapped in ice. The air is thus always younger than the surrounding ice. The...
Published in: | Climate of the Past |
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Main Authors: | , , , , |
Other Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2017
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Online Access: | https://hal.science/hal-01584118 https://hal.science/hal-01584118/document https://hal.science/hal-01584118/file/cp-13-833-2017.pdf https://doi.org/10.5194/cp-13-833-2017 |
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ftuniparissaclay:oai:HAL:hal-01584118v1 |
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openpolar |
institution |
Open Polar |
collection |
Archives ouvertes de Paris-Saclay |
op_collection_id |
ftuniparissaclay |
language |
English |
topic |
[SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Bréant, Camille Martinerie, Patricia Orsi, Anaïs Arnaud, Laurent Landais, Amaëlle Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
topic_facet |
[SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience The transformation of snow into ice is a complex phenomenon that is difficult to model. Depending on surface temperature and accumulation rate, it may take several decades to millennia for air to be entrapped in ice. The air is thus always younger than the surrounding ice. The resulting gas–ice age difference is essential to documenting the phasing between CO 2 and temperature changes, especially during deglaciations. The air trapping depth can be inferred in the past using a firn densification model, or using δ 15 N of air measured in ice cores. All firn densification models applied to deglaciations show a large disagreement with δ 15 N measurements at several sites in East Antarctica, predicting larger firn thickness during the Last Glacial Maximum, whereas δ 15 N suggests a reduced firn thickness compared to the Holocene. Here we present modifications of the LGGE firn densification model, which significantly reduce the model–data mismatch for the gas trapping depth evolution over the last deglaciation at the coldest sites in East Antarctica (Vostok, Dome C), while preserving the good agreement between measured and modelled modern firn density profiles. In particular, we introduce a dependency of the creep factor on temperature and impurities in the firn densification rate calculation. The temperature influence intends to reflect the dominance of different mechanisms for firn compaction at different temperatures. We show that both the new temperature parameterization and the influence of impurities contribute to the increased agreement between modelled and measured δ 15 N evolution during the last deglaciation at sites with low temperature and low accumulation rate, such as Dome C or Vostok. We find that a very low sensitivity of the densification rate to temperature has to be used in the coldest conditions. The inclusion of impurity effects improves the agreement between modelled and measured δ 15 N at cold East Antarctic sites during the last deglaciation, but deteriorates the ... |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Glaces et Continents, Climats et Isotopes Stables (GLACCIOS) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) |
format |
Article in Journal/Newspaper |
author |
Bréant, Camille Martinerie, Patricia Orsi, Anaïs Arnaud, Laurent Landais, Amaëlle |
author_facet |
Bréant, Camille Martinerie, Patricia Orsi, Anaïs Arnaud, Laurent Landais, Amaëlle |
author_sort |
Bréant, Camille |
title |
Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
title_short |
Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
title_full |
Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
title_fullStr |
Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
title_full_unstemmed |
Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
title_sort |
modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://hal.science/hal-01584118 https://hal.science/hal-01584118/document https://hal.science/hal-01584118/file/cp-13-833-2017.pdf https://doi.org/10.5194/cp-13-833-2017 |
geographic |
Antarctic East Antarctica |
geographic_facet |
Antarctic East Antarctica |
genre |
Antarc* Antarctic Antarctica East Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica |
op_source |
ISSN: 1814-9324 EISSN: 1814-9332 Climate of the Past https://hal.science/hal-01584118 Climate of the Past, 2017, 13 (7), pp.833-853. ⟨10.5194/cp-13-833-2017⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/cp-13-833-2017 hal-01584118 https://hal.science/hal-01584118 https://hal.science/hal-01584118/document https://hal.science/hal-01584118/file/cp-13-833-2017.pdf doi:10.5194/cp-13-833-2017 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/cp-13-833-2017 |
container_title |
Climate of the Past |
container_volume |
13 |
container_issue |
7 |
container_start_page |
833 |
op_container_end_page |
853 |
_version_ |
1802012214913138688 |
spelling |
ftuniparissaclay:oai:HAL:hal-01584118v1 2024-06-16T07:35:31+00:00 Modelling firn thickness evolution during the last deglaciation: constraints on sensitivity to temperature and impurities Bréant, Camille Martinerie, Patricia Orsi, Anaïs Arnaud, Laurent Landais, Amaëlle Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Glaces et Continents, Climats et Isotopes Stables (GLACCIOS) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) 2017 https://hal.science/hal-01584118 https://hal.science/hal-01584118/document https://hal.science/hal-01584118/file/cp-13-833-2017.pdf https://doi.org/10.5194/cp-13-833-2017 en eng HAL CCSD European Geosciences Union (EGU) info:eu-repo/semantics/altIdentifier/doi/10.5194/cp-13-833-2017 hal-01584118 https://hal.science/hal-01584118 https://hal.science/hal-01584118/document https://hal.science/hal-01584118/file/cp-13-833-2017.pdf doi:10.5194/cp-13-833-2017 info:eu-repo/semantics/OpenAccess ISSN: 1814-9324 EISSN: 1814-9332 Climate of the Past https://hal.science/hal-01584118 Climate of the Past, 2017, 13 (7), pp.833-853. ⟨10.5194/cp-13-833-2017⟩ [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2017 ftuniparissaclay https://doi.org/10.5194/cp-13-833-2017 2024-05-17T00:12:18Z International audience The transformation of snow into ice is a complex phenomenon that is difficult to model. Depending on surface temperature and accumulation rate, it may take several decades to millennia for air to be entrapped in ice. The air is thus always younger than the surrounding ice. The resulting gas–ice age difference is essential to documenting the phasing between CO 2 and temperature changes, especially during deglaciations. The air trapping depth can be inferred in the past using a firn densification model, or using δ 15 N of air measured in ice cores. All firn densification models applied to deglaciations show a large disagreement with δ 15 N measurements at several sites in East Antarctica, predicting larger firn thickness during the Last Glacial Maximum, whereas δ 15 N suggests a reduced firn thickness compared to the Holocene. Here we present modifications of the LGGE firn densification model, which significantly reduce the model–data mismatch for the gas trapping depth evolution over the last deglaciation at the coldest sites in East Antarctica (Vostok, Dome C), while preserving the good agreement between measured and modelled modern firn density profiles. In particular, we introduce a dependency of the creep factor on temperature and impurities in the firn densification rate calculation. The temperature influence intends to reflect the dominance of different mechanisms for firn compaction at different temperatures. We show that both the new temperature parameterization and the influence of impurities contribute to the increased agreement between modelled and measured δ 15 N evolution during the last deglaciation at sites with low temperature and low accumulation rate, such as Dome C or Vostok. We find that a very low sensitivity of the densification rate to temperature has to be used in the coldest conditions. The inclusion of impurity effects improves the agreement between modelled and measured δ 15 N at cold East Antarctic sites during the last deglaciation, but deteriorates the ... Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Archives ouvertes de Paris-Saclay Antarctic East Antarctica Climate of the Past 13 7 833 853 |