North African humid periods over the past 800,000 years
The Sahara region has experienced periodic wet periods over the Quaternary and beyond. These North African Humid Periods (NAHPs) are astronomically paced by precession which controls the intensity of the African monsoon system. However, most climate models cannot reconcile the magnitude of these eve...
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ftpubmed:oai:pubmedcentral.nih.gov:10491769 2023-10-09T21:52:24+02:00 North African humid periods over the past 800,000 years Armstrong, Edward Tallavaara, Miikka Hopcroft, Peter O. Valdes, Paul J. 2023-09-08 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10491769/ http://www.ncbi.nlm.nih.gov/pubmed/37684244 https://doi.org/10.1038/s41467-023-41219-4 en eng Nature Publishing Group UK http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10491769/ http://www.ncbi.nlm.nih.gov/pubmed/37684244 http://dx.doi.org/10.1038/s41467-023-41219-4 © Springer Nature Limited 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . Nat Commun Article Text 2023 ftpubmed https://doi.org/10.1038/s41467-023-41219-4 2023-09-17T00:43:17Z The Sahara region has experienced periodic wet periods over the Quaternary and beyond. These North African Humid Periods (NAHPs) are astronomically paced by precession which controls the intensity of the African monsoon system. However, most climate models cannot reconcile the magnitude of these events and so the driving mechanisms remain poorly constrained. Here, we utilise a recently developed version of the HadCM3B coupled climate model that simulates 20 NAHPs over the past 800 kyr which have good agreement with NAHPs identified in proxy data. Our results show that precession determines NAHP pacing, but we identify that their amplitude is strongly linked to eccentricity via its control over ice sheet extent. During glacial periods, enhanced ice-albedo driven cooling suppresses NAHP amplitude at precession minima, when humid conditions would otherwise be expected. This highlights the importance of both precession and eccentricity, and the role of high latitude processes in determining the timing and amplitude of the NAHPs. This may have implications for the out of Africa dispersal of plants and animals throughout the Quaternary. Text Ice Sheet PubMed Central (PMC) Nature Communications 14 1 |
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Article Armstrong, Edward Tallavaara, Miikka Hopcroft, Peter O. Valdes, Paul J. North African humid periods over the past 800,000 years |
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The Sahara region has experienced periodic wet periods over the Quaternary and beyond. These North African Humid Periods (NAHPs) are astronomically paced by precession which controls the intensity of the African monsoon system. However, most climate models cannot reconcile the magnitude of these events and so the driving mechanisms remain poorly constrained. Here, we utilise a recently developed version of the HadCM3B coupled climate model that simulates 20 NAHPs over the past 800 kyr which have good agreement with NAHPs identified in proxy data. Our results show that precession determines NAHP pacing, but we identify that their amplitude is strongly linked to eccentricity via its control over ice sheet extent. During glacial periods, enhanced ice-albedo driven cooling suppresses NAHP amplitude at precession minima, when humid conditions would otherwise be expected. This highlights the importance of both precession and eccentricity, and the role of high latitude processes in determining the timing and amplitude of the NAHPs. This may have implications for the out of Africa dispersal of plants and animals throughout the Quaternary. |
format |
Text |
author |
Armstrong, Edward Tallavaara, Miikka Hopcroft, Peter O. Valdes, Paul J. |
author_facet |
Armstrong, Edward Tallavaara, Miikka Hopcroft, Peter O. Valdes, Paul J. |
author_sort |
Armstrong, Edward |
title |
North African humid periods over the past 800,000 years |
title_short |
North African humid periods over the past 800,000 years |
title_full |
North African humid periods over the past 800,000 years |
title_fullStr |
North African humid periods over the past 800,000 years |
title_full_unstemmed |
North African humid periods over the past 800,000 years |
title_sort |
north african humid periods over the past 800,000 years |
publisher |
Nature Publishing Group UK |
publishDate |
2023 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10491769/ http://www.ncbi.nlm.nih.gov/pubmed/37684244 https://doi.org/10.1038/s41467-023-41219-4 |
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Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Nat Commun |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10491769/ http://www.ncbi.nlm.nih.gov/pubmed/37684244 http://dx.doi.org/10.1038/s41467-023-41219-4 |
op_rights |
© Springer Nature Limited 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
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https://doi.org/10.1038/s41467-023-41219-4 |
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Nature Communications |
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14 |
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