Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening
During the first half of the Holocene (11,000 to 5,000 years ago) the Northern Hemisphere experienced a strengthening of the monsoonal regime, with climate reconstructions robustly suggesting a greening of the Sahara region. Paleoclimate archives also show that this so-called African Humid Period (A...
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ftarchimer:oai:archimer.ifremer.fr:98751 2024-03-24T09:03:41+00:00 Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening Gaetani, Marco Messori, Gabriele Pausata, Francesco S. R. Tiwari, Shivangi Alvarez Castro, M. Carmen Zhang, Qiong 2024-02-02 application/pdf https://archimer.ifremer.fr/doc/00876/98751/108361.pdf https://doi.org/10.5194/egusphere-2024-272 https://archimer.ifremer.fr/doc/00876/98751/ eng eng Copernicus GmbH https://archimer.ifremer.fr/doc/00876/98751/108361.pdf doi:10.5194/egusphere-2024-272 https://archimer.ifremer.fr/doc/00876/98751/ info:eu-repo/semantics/openAccess restricted use EGUsphere (Copernicus GmbH) In Press text Article info:eu-repo/semantics/article 2024 ftarchimer https://doi.org/10.5194/egusphere-2024-272 2024-02-27T08:55:35Z During the first half of the Holocene (11,000 to 5,000 years ago) the Northern Hemisphere experienced a strengthening of the monsoonal regime, with climate reconstructions robustly suggesting a greening of the Sahara region. Paleoclimate archives also show that this so-called African Humid Period (AHP) was accompanied by changes in the climate conditions at mid to high latitudes. However, inconsistencies still exist in reconstructions of the mid-Holocene (MH) climate at mid-latitudes, and model simulations provide limited support to reduce these discrepancies. In this paper, a set of simulations performed with a climate model is used to investigate the hitherto unexplored impact of the Saharan greening on mid-latitude atmospheric circulation during the MH. Numerical simulations show a year-round impact of the Saharan greening on the main circulation features in the Northern Hemisphere, especially during boreal summer when the African monsoon develops. Key findings include a westward shift of the global Walker Circulation, leading to a modification of the North Atlantic jet stream in summer and the North Pacific jet stream in winter. Furthermore, the Saharan greening modifies the atmospheric synoptic circulation over the North Atlantic, transitioning the North Atlantic Oscillation phase from prevailingly positive to neutral-to-negative in winter and summer. This study provides a first constraint on the Saharan greening influence on northern midlatitudes, indicating new opportunities for understanding the MH climate anomalies in regions such as North America and Eurasia. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Pacific |
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Open Polar |
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Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
During the first half of the Holocene (11,000 to 5,000 years ago) the Northern Hemisphere experienced a strengthening of the monsoonal regime, with climate reconstructions robustly suggesting a greening of the Sahara region. Paleoclimate archives also show that this so-called African Humid Period (AHP) was accompanied by changes in the climate conditions at mid to high latitudes. However, inconsistencies still exist in reconstructions of the mid-Holocene (MH) climate at mid-latitudes, and model simulations provide limited support to reduce these discrepancies. In this paper, a set of simulations performed with a climate model is used to investigate the hitherto unexplored impact of the Saharan greening on mid-latitude atmospheric circulation during the MH. Numerical simulations show a year-round impact of the Saharan greening on the main circulation features in the Northern Hemisphere, especially during boreal summer when the African monsoon develops. Key findings include a westward shift of the global Walker Circulation, leading to a modification of the North Atlantic jet stream in summer and the North Pacific jet stream in winter. Furthermore, the Saharan greening modifies the atmospheric synoptic circulation over the North Atlantic, transitioning the North Atlantic Oscillation phase from prevailingly positive to neutral-to-negative in winter and summer. This study provides a first constraint on the Saharan greening influence on northern midlatitudes, indicating new opportunities for understanding the MH climate anomalies in regions such as North America and Eurasia. |
format |
Article in Journal/Newspaper |
author |
Gaetani, Marco Messori, Gabriele Pausata, Francesco S. R. Tiwari, Shivangi Alvarez Castro, M. Carmen Zhang, Qiong |
spellingShingle |
Gaetani, Marco Messori, Gabriele Pausata, Francesco S. R. Tiwari, Shivangi Alvarez Castro, M. Carmen Zhang, Qiong Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
author_facet |
Gaetani, Marco Messori, Gabriele Pausata, Francesco S. R. Tiwari, Shivangi Alvarez Castro, M. Carmen Zhang, Qiong |
author_sort |
Gaetani, Marco |
title |
Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
title_short |
Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
title_full |
Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
title_fullStr |
Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
title_full_unstemmed |
Mid-Holocene climate at mid-latitudes: assessing the impact of the Saharan greening |
title_sort |
mid-holocene climate at mid-latitudes: assessing the impact of the saharan greening |
publisher |
Copernicus GmbH |
publishDate |
2024 |
url |
https://archimer.ifremer.fr/doc/00876/98751/108361.pdf https://doi.org/10.5194/egusphere-2024-272 https://archimer.ifremer.fr/doc/00876/98751/ |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
EGUsphere (Copernicus GmbH) In Press |
op_relation |
https://archimer.ifremer.fr/doc/00876/98751/108361.pdf doi:10.5194/egusphere-2024-272 https://archimer.ifremer.fr/doc/00876/98751/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/egusphere-2024-272 |
_version_ |
1794404620210012160 |