Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D
Variations in the Atlantic Meridional Overturning Circulation (AMOC) are associated with Northern Hemispheric and global climate shifts. Thermal thresholds of the AMOC have been found in a hierarchy of numerical circulation models, and there is an increasing body of evidence for the existence of hig...
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ftcopernicus:oai:publications.copernicus.org:cp115308 2024-06-23T07:56:43+00:00 Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D Adloff, Markus Pöppelmeier, Frerk Jeltsch-Thömmes, Aurich Stocker, Thomas F. Joos, Fortunat 2024-06-03 application/pdf https://doi.org/10.5194/cp-20-1233-2024 https://cp.copernicus.org/articles/20/1233/2024/ eng eng doi:10.5194/cp-20-1233-2024 https://cp.copernicus.org/articles/20/1233/2024/ eISSN: 1814-9332 Text 2024 ftcopernicus https://doi.org/10.5194/cp-20-1233-2024 2024-06-13T01:24:17Z Variations in the Atlantic Meridional Overturning Circulation (AMOC) are associated with Northern Hemispheric and global climate shifts. Thermal thresholds of the AMOC have been found in a hierarchy of numerical circulation models, and there is an increasing body of evidence for the existence of highly sensitive AMOC modes where small perturbations can cause disproportionately large circulation and hence climatic changes. We discovered such thresholds in simulations with the intermediate-complexity Earth system model Bern3D, which is highly computationally efficient, allowing for studying this non-linear behaviour systematically over entire glacial cycles. By simulating the AMOC under different magnitudes of orbitally paced changes in radiative forcing over the last 788 000 years, we show that up to three thermal thresholds are crossed during glacial cycles in Bern3D and that thermal forcing could have destabilised the AMOC repeatedly. We present the circulation and sea ice patterns that characterise the stable circulation modes between which this model oscillates during a glacial cycle and assess how often and when thermal forcing could have preconditioned the Bern3D AMOC for abrupt shifts over the last 788 kyr. Text Sea ice Copernicus Publications: E-Journals Climate of the Past 20 6 1233 1250 |
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Copernicus Publications: E-Journals |
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English |
description |
Variations in the Atlantic Meridional Overturning Circulation (AMOC) are associated with Northern Hemispheric and global climate shifts. Thermal thresholds of the AMOC have been found in a hierarchy of numerical circulation models, and there is an increasing body of evidence for the existence of highly sensitive AMOC modes where small perturbations can cause disproportionately large circulation and hence climatic changes. We discovered such thresholds in simulations with the intermediate-complexity Earth system model Bern3D, which is highly computationally efficient, allowing for studying this non-linear behaviour systematically over entire glacial cycles. By simulating the AMOC under different magnitudes of orbitally paced changes in radiative forcing over the last 788 000 years, we show that up to three thermal thresholds are crossed during glacial cycles in Bern3D and that thermal forcing could have destabilised the AMOC repeatedly. We present the circulation and sea ice patterns that characterise the stable circulation modes between which this model oscillates during a glacial cycle and assess how often and when thermal forcing could have preconditioned the Bern3D AMOC for abrupt shifts over the last 788 kyr. |
format |
Text |
author |
Adloff, Markus Pöppelmeier, Frerk Jeltsch-Thömmes, Aurich Stocker, Thomas F. Joos, Fortunat |
spellingShingle |
Adloff, Markus Pöppelmeier, Frerk Jeltsch-Thömmes, Aurich Stocker, Thomas F. Joos, Fortunat Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
author_facet |
Adloff, Markus Pöppelmeier, Frerk Jeltsch-Thömmes, Aurich Stocker, Thomas F. Joos, Fortunat |
author_sort |
Adloff, Markus |
title |
Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
title_short |
Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
title_full |
Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
title_fullStr |
Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
title_full_unstemmed |
Multiple thermal Atlantic Meridional Overturning Circulation thresholds in the intermediate complexity model Bern3D |
title_sort |
multiple thermal atlantic meridional overturning circulation thresholds in the intermediate complexity model bern3d |
publishDate |
2024 |
url |
https://doi.org/10.5194/cp-20-1233-2024 https://cp.copernicus.org/articles/20/1233/2024/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-20-1233-2024 https://cp.copernicus.org/articles/20/1233/2024/ |
op_doi |
https://doi.org/10.5194/cp-20-1233-2024 |
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Climate of the Past |
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20 |
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6 |
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1233 |
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1250 |
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1802650005820932096 |