Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP
From 10 to 8 ka BP (thousand years before present), paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of the Southern Hemisphere. During this interval, temperatures estimated from proxy data decrease by 0.8 °C over Antarctica and 1.2 °C over the Southern Ocean. In or...
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ftdoajarticles:oai:doaj.org/article:5f972a8920984fa59b76a200b70c50c1 2023-05-15T13:40:39+02:00 Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP P. Mathiot H. Goosse X. Crosta B. Stenni M. Braida H. Renssen C. J. Van Meerbeeck V. Masson-Delmotte A. Mairesse S. Dubinkina 2013-04-01T00:00:00Z https://doi.org/10.5194/cp-9-887-2013 https://doaj.org/article/5f972a8920984fa59b76a200b70c50c1 EN eng Copernicus Publications http://www.clim-past.net/9/887/2013/cp-9-887-2013.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-9-887-2013 1814-9324 1814-9332 https://doaj.org/article/5f972a8920984fa59b76a200b70c50c1 Climate of the Past, Vol 9, Iss 2, Pp 887-901 (2013) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2013 ftdoajarticles https://doi.org/10.5194/cp-9-887-2013 2022-12-31T14:39:09Z From 10 to 8 ka BP (thousand years before present), paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of the Southern Hemisphere. During this interval, temperatures estimated from proxy data decrease by 0.8 °C over Antarctica and 1.2 °C over the Southern Ocean. In order to study the causes of this cooling, simulations covering the early Holocene have been performed with the climate model of intermediate complexity LOVECLIM constrained to follow the signal recorded in climate proxies using a data assimilation method based on a particle filtering approach. The selected proxies represent oceanic and atmospheric surface temperature in the Southern Hemisphere derived from terrestrial, marine and glaciological records. Two mechanisms previously suggested to explain the 10–8 ka BP cooling pattern are investigated using the data assimilation approach in our model. The first hypothesis is a change in atmospheric circulation, and the second one is a cooling of the sea surface temperature in the Southern Ocean, driven in our experimental setup by the impact of an increased West Antarctic melting rate on ocean circulation. For the atmosphere hypothesis, the climate state obtained by data assimilation produces a modification of the meridional atmospheric circulation leading to a 0.5 °C Antarctic cooling from 10 to 8 ka BP compared to the simulation without data assimilation, without congruent cooling of the atmospheric and sea surface temperature in the Southern Ocean. For the ocean hypothesis, the increased West Antarctic freshwater flux constrainted by data assimilation (+100 mSv from 10 to 8 ka BP) leads to an oceanic cooling of 0.7 °C and a strengthening of Southern Hemisphere westerlies (+6%). Thus, according to our experiments, the observed cooling in Antarctic and the Southern Ocean proxy records can only be reconciled with the reconstructions by the combination of a modified atmospheric circulation and an enhanced freshwater flux. Article in Journal/Newspaper Antarc* Antarctic Antarctica Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean Climate of the Past 9 2 887 901 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 P. Mathiot H. Goosse X. Crosta B. Stenni M. Braida H. Renssen C. J. Van Meerbeeck V. Masson-Delmotte A. Mairesse S. Dubinkina Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
From 10 to 8 ka BP (thousand years before present), paleoclimate records show an atmospheric and oceanic cooling in the high latitudes of the Southern Hemisphere. During this interval, temperatures estimated from proxy data decrease by 0.8 °C over Antarctica and 1.2 °C over the Southern Ocean. In order to study the causes of this cooling, simulations covering the early Holocene have been performed with the climate model of intermediate complexity LOVECLIM constrained to follow the signal recorded in climate proxies using a data assimilation method based on a particle filtering approach. The selected proxies represent oceanic and atmospheric surface temperature in the Southern Hemisphere derived from terrestrial, marine and glaciological records. Two mechanisms previously suggested to explain the 10–8 ka BP cooling pattern are investigated using the data assimilation approach in our model. The first hypothesis is a change in atmospheric circulation, and the second one is a cooling of the sea surface temperature in the Southern Ocean, driven in our experimental setup by the impact of an increased West Antarctic melting rate on ocean circulation. For the atmosphere hypothesis, the climate state obtained by data assimilation produces a modification of the meridional atmospheric circulation leading to a 0.5 °C Antarctic cooling from 10 to 8 ka BP compared to the simulation without data assimilation, without congruent cooling of the atmospheric and sea surface temperature in the Southern Ocean. For the ocean hypothesis, the increased West Antarctic freshwater flux constrainted by data assimilation (+100 mSv from 10 to 8 ka BP) leads to an oceanic cooling of 0.7 °C and a strengthening of Southern Hemisphere westerlies (+6%). Thus, according to our experiments, the observed cooling in Antarctic and the Southern Ocean proxy records can only be reconciled with the reconstructions by the combination of a modified atmospheric circulation and an enhanced freshwater flux. |
format |
Article in Journal/Newspaper |
author |
P. Mathiot H. Goosse X. Crosta B. Stenni M. Braida H. Renssen C. J. Van Meerbeeck V. Masson-Delmotte A. Mairesse S. Dubinkina |
author_facet |
P. Mathiot H. Goosse X. Crosta B. Stenni M. Braida H. Renssen C. J. Van Meerbeeck V. Masson-Delmotte A. Mairesse S. Dubinkina |
author_sort |
P. Mathiot |
title |
Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
title_short |
Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
title_full |
Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
title_fullStr |
Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
title_full_unstemmed |
Using data assimilation to investigate the causes of Southern Hemisphere high latitude cooling from 10 to 8 ka BP |
title_sort |
using data assimilation to investigate the causes of southern hemisphere high latitude cooling from 10 to 8 ka bp |
publisher |
Copernicus Publications |
publishDate |
2013 |
url |
https://doi.org/10.5194/cp-9-887-2013 https://doaj.org/article/5f972a8920984fa59b76a200b70c50c1 |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Southern Ocean |
op_source |
Climate of the Past, Vol 9, Iss 2, Pp 887-901 (2013) |
op_relation |
http://www.clim-past.net/9/887/2013/cp-9-887-2013.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-9-887-2013 1814-9324 1814-9332 https://doaj.org/article/5f972a8920984fa59b76a200b70c50c1 |
op_doi |
https://doi.org/10.5194/cp-9-887-2013 |
container_title |
Climate of the Past |
container_volume |
9 |
container_issue |
2 |
container_start_page |
887 |
op_container_end_page |
901 |
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1766137968170369024 |