The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study
Abstract Results from a study inspecting the origins of multidecadal variability in the North Atlantic sea surface temperature (NASST) are presented. The authors target in particular the 1940–75 "warm-to-cold" transition, an event that is generally framed in the context of the longer-term...
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ftopenaccessrep:oai:zenodo.org:107011 2023-10-25T01:41:06+02:00 The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study Alessio Bellucci Annarita Mariotti Silvio Gualdi 2017-08-17 https://www.openaccessrepository.it/record/107011 https://doi.org/10.1175/jcli-d-16-0301.1 eng eng url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/107011 doi:10.1175/jcli-d-16-0301.1 info:eu-repo/semantics/openAccess Atmospheric Science info:eu-repo/semantics/article publication-article 2017 ftopenaccessrep https://doi.org/10.1175/jcli-d-16-0301.1 2023-09-26T22:22:06Z Abstract Results from a study inspecting the origins of multidecadal variability in the North Atlantic sea surface temperature (NASST) are presented. The authors target in particular the 1940–75 "warm-to-cold" transition, an event that is generally framed in the context of the longer-term Atlantic multidecadal variability (AMV) cycle, in turn associated with the Atlantic meridional overturning circulation (AMOC) internal variability. Here the authors examine the ability of uninitialized, historical integrations from the phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive to retrospectively reproduce this specific episode of twentieth-century climatic history, under a hierarchy of forcing conditions. For this purpose, both standard and so-called historical Misc CMIP5 simulations of the historical climate (combining selected natural and anthropogenic forcings) are exploited. Based on this multimodel analysis, evidence is found for a significant influence of anthropogenic agents on multidecadal sea surface temperature (SST) fluctuations across the Atlantic sector, suggesting that anthropogenic aerosols and greenhouse gases might have played a key role in the 1940–75 North Atlantic cooling. However, the diagnosed forced response in CMIP5 models appears to be affected by a large uncertainty, with only a limited subset of models displaying significant skill in reproducing the mid-twentieth-century NASST cooling. Such uncertainty originates from the existence of well-defined behavioral clusters within the analyzed CMIP5 ensembles, with the bulk of the models splitting into two main clusters. Such a strong polarization calls for some caution when using a multimodel ensemble mean in climate model analyses, as averaging across fairly distinct model populations may result, through mutual cancellation, in a rather artificial description of the actual multimodel ensemble behavior. A potentially important role for both anthropogenic aerosols and greenhouse gases with regard to the observed North Atlantic ... Article in Journal/Newspaper North Atlantic Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository Journal of Climate 30 18 7317 7337 |
institution |
Open Polar |
collection |
Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
op_collection_id |
ftopenaccessrep |
language |
English |
topic |
Atmospheric Science |
spellingShingle |
Atmospheric Science Alessio Bellucci Annarita Mariotti Silvio Gualdi The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
topic_facet |
Atmospheric Science |
description |
Abstract Results from a study inspecting the origins of multidecadal variability in the North Atlantic sea surface temperature (NASST) are presented. The authors target in particular the 1940–75 "warm-to-cold" transition, an event that is generally framed in the context of the longer-term Atlantic multidecadal variability (AMV) cycle, in turn associated with the Atlantic meridional overturning circulation (AMOC) internal variability. Here the authors examine the ability of uninitialized, historical integrations from the phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive to retrospectively reproduce this specific episode of twentieth-century climatic history, under a hierarchy of forcing conditions. For this purpose, both standard and so-called historical Misc CMIP5 simulations of the historical climate (combining selected natural and anthropogenic forcings) are exploited. Based on this multimodel analysis, evidence is found for a significant influence of anthropogenic agents on multidecadal sea surface temperature (SST) fluctuations across the Atlantic sector, suggesting that anthropogenic aerosols and greenhouse gases might have played a key role in the 1940–75 North Atlantic cooling. However, the diagnosed forced response in CMIP5 models appears to be affected by a large uncertainty, with only a limited subset of models displaying significant skill in reproducing the mid-twentieth-century NASST cooling. Such uncertainty originates from the existence of well-defined behavioral clusters within the analyzed CMIP5 ensembles, with the bulk of the models splitting into two main clusters. Such a strong polarization calls for some caution when using a multimodel ensemble mean in climate model analyses, as averaging across fairly distinct model populations may result, through mutual cancellation, in a rather artificial description of the actual multimodel ensemble behavior. A potentially important role for both anthropogenic aerosols and greenhouse gases with regard to the observed North Atlantic ... |
format |
Article in Journal/Newspaper |
author |
Alessio Bellucci Annarita Mariotti Silvio Gualdi |
author_facet |
Alessio Bellucci Annarita Mariotti Silvio Gualdi |
author_sort |
Alessio Bellucci |
title |
The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
title_short |
The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
title_full |
The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
title_fullStr |
The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
title_full_unstemmed |
The Role of Forcings in the Twentieth-Century North Atlantic Multidecadal Variability: The 1940–75 North Atlantic Cooling Case Study |
title_sort |
role of forcings in the twentieth-century north atlantic multidecadal variability: the 1940–75 north atlantic cooling case study |
publishDate |
2017 |
url |
https://www.openaccessrepository.it/record/107011 https://doi.org/10.1175/jcli-d-16-0301.1 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/107011 doi:10.1175/jcli-d-16-0301.1 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/jcli-d-16-0301.1 |
container_title |
Journal of Climate |
container_volume |
30 |
container_issue |
18 |
container_start_page |
7317 |
op_container_end_page |
7337 |
_version_ |
1780737105377361920 |