The Atlantic Multidecadal Variability in Observations and in a Large Historical Multimodel Ensemble: Forced and Internal Variability.
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| Title: | The Atlantic Multidecadal Variability in Observations and in a Large Historical Multimodel Ensemble: Forced and Internal Variability. |
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| Authors: | Christiansen, Bo1 (AUTHOR) boc@dmi.dk, Yang, Shuting1 (AUTHOR), Drews, Annika1 (AUTHOR) |
| Source: | Journal of Climate. Jun2025, Vol. 38 Issue 12, p2761-2781. 21p. |
| Subjects: | North Atlantic oscillation, Atmospheric models, Definitions, Ocean, Polynomials |
| Abstract: | We investigate the Atlantic multidecadal variability (AMV) in observations and in a large CMIP6 historical climate model ensemble. We compare four different definitions of the AMV aimed at extracting the variability intrinsic to the Atlantic region. They are based on removing from the Atlantic temperature the linear or polynomial trend, the part congruent to the global average, or the part congruent to the multimodel mean of the global average. The definitions agree on the well-known low-frequency oscillatory variability in observations but show larger differences for the models. In general, large differences between ensemble members are found. We estimate the forced response in the AMV as the mean of the multimodel ensemble. This response converges fast with the ensemble size and saturates for a size of around 25. The forced response resembles the observed low-frequency oscillatory variability for the detrended AMV definitions, but these definitions are also the most ineffective in removing the forced global mean signal. The forced response is very weak for the other definitions, and few of their individual ensemble members show oscillatory variability and even fewer with the observed phase. The observed spatial temperature pattern related to the AMV is well captured for all AMV definitions but is more confined for the definitions with the global means removed. These definitions also depend the least on the considered period. The observed instantaneous connection between NAO and AMV is well represented in the models for all definitions. Only nonsignificant evidence of NAO leading the AMV on decadal time scales is found. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Climate is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 185965020 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The Atlantic Multidecadal Variability in Observations and in a Large Historical Multimodel Ensemble: Forced and Internal Variability. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Christiansen%2C+Bo%22">Christiansen, Bo</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> boc@dmi.dk</i><br /><searchLink fieldCode="AR" term="%22Yang%2C+Shuting%22">Yang, Shuting</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Drews%2C+Annika%22">Drews, Annika</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Climate%22">Journal of Climate</searchLink>. Jun2025, Vol. 38 Issue 12, p2761-2781. 21p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22North+Atlantic+oscillation%22">North Atlantic oscillation</searchLink><br /><searchLink fieldCode="DE" term="%22Atmospheric+models%22">Atmospheric models</searchLink><br /><searchLink fieldCode="DE" term="%22Definitions%22">Definitions</searchLink><br /><searchLink fieldCode="DE" term="%22Ocean%22">Ocean</searchLink><br /><searchLink fieldCode="DE" term="%22Polynomials%22">Polynomials</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: We investigate the Atlantic multidecadal variability (AMV) in observations and in a large CMIP6 historical climate model ensemble. We compare four different definitions of the AMV aimed at extracting the variability intrinsic to the Atlantic region. They are based on removing from the Atlantic temperature the linear or polynomial trend, the part congruent to the global average, or the part congruent to the multimodel mean of the global average. The definitions agree on the well-known low-frequency oscillatory variability in observations but show larger differences for the models. In general, large differences between ensemble members are found. We estimate the forced response in the AMV as the mean of the multimodel ensemble. This response converges fast with the ensemble size and saturates for a size of around 25. The forced response resembles the observed low-frequency oscillatory variability for the detrended AMV definitions, but these definitions are also the most ineffective in removing the forced global mean signal. The forced response is very weak for the other definitions, and few of their individual ensemble members show oscillatory variability and even fewer with the observed phase. The observed spatial temperature pattern related to the AMV is well captured for all AMV definitions but is more confined for the definitions with the global means removed. These definitions also depend the least on the considered period. The observed instantaneous connection between NAO and AMV is well represented in the models for all definitions. Only nonsignificant evidence of NAO leading the AMV on decadal time scales is found. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Climate is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=185965020 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1175/JCLI-D-24-0310.1 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 21 StartPage: 2761 Subjects: – SubjectFull: North Atlantic oscillation Type: general – SubjectFull: Atmospheric models Type: general – SubjectFull: Definitions Type: general – SubjectFull: Ocean Type: general – SubjectFull: Polynomials Type: general Titles: – TitleFull: The Atlantic Multidecadal Variability in Observations and in a Large Historical Multimodel Ensemble: Forced and Internal Variability. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Christiansen, Bo – PersonEntity: Name: NameFull: Yang, Shuting – PersonEntity: Name: NameFull: Drews, Annika IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 06 Text: Jun2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 08948755 Numbering: – Type: volume Value: 38 – Type: issue Value: 12 Titles: – TitleFull: Journal of Climate Type: main |
| ResultId | 1 |
