Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence

Müller-Plath, Gisela

Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence

dc.contributor.author	Müller-Plath, Gisela
dc.date.accessioned	2020-12-17T08:13:27Z
dc.date.available	2020-12-17T08:13:27Z
dc.date.issued	2020-11-26
dc.date.updated	2020-12-10T06:22:11Z
dc.description.abstract	The present paper contributes a critical commentary on the recent finding by Mann, M. E., Steinman, B. A. and Miller, S. K (2020). Absence of internal multidecadal and interdecadal oscillations in climate model simulations. Nat. Commun. 11, 1–9. Climate oscillations are recurring large-scale fluctuations in the surface temperatures of the oceans in connection with the atmosphere. This commentary focuses on the Pacific Decadal Oscillation (PDO, interdecadal timescale) and the Atlantic Multidecadal Oscillation (AMO, multidecadal timescale), which have been regarded as intrinsic climate drivers on the adjacent continents in numerous studies based on observations and paleoclimate reconstructions (Henley, 2017; O’Reilly et al., 2017). In a recent paper, Michael E. Mann and colleagues (Mann et al., 2020, hereafter M20) fail to find a PDO signal in global measured and modeled temperatures that is statistically different from noise. They further propose that the significant AMO-like signal is mainly due to anthropogenic aerosols in the 20th century, and to statistical artifacts before. Therefore they doubt the intrinsic nature of the two oscillations. The present paper shows that M20’s results are largely artifacts themselves with issues ranging from using inadequate data and referencing improper literature on anthropogenic aerosols with regards to the AMO to inappropriately interpreting the results with regards to the PDO. After briefly sketching the rationale and method of M20, I will elaborate on these three points. M20 (p. 3) argue that any truly oscillatory AMO or PDO signals should generate a spatially coherent and large-scale variability pattern in the climate system with a narrowband signature in the frequency domain. They search for such signals in global (observed and modeled) temperature grids of different time lengths with the multi-taper method of singular value decomposition (MTM-SVD), which was developed and widely applied by Mann and Park (Mann and Park, 1994; Mann et al., 1995; Mann and Park, 1999). Significance tests of the test statistic LFV (local fractional variance) are carried out with Monte Carlo simulations generated according to the null hypothesis of colored (red) noise. The method can generally be applied to reconstruct the time course and the spatial pattern of any potential oscillatory climate signal.	en
dc.description.sponsorship	TU Berlin, Open-Access-Mittel – 2020	en
dc.identifier.eissn	2296-6463
dc.identifier.uri	https://depositonce.tu-berlin.de/handle/11303/12225
dc.identifier.uri	http://dx.doi.org/10.14279/depositonce-11100
dc.language.iso	en	en
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	en
dc.subject.ddc	550 Geowissenschaften	de
dc.subject.other	Pacific Decadal Oscillation	en
dc.subject.other	Atlantic Multidecadal Oscillation	en
dc.subject.other	sulfate aerosols	en
dc.subject.other	climate oscillations	en
dc.subject.other	multi-taper method of singular value decomposition spectral analysis	en
dc.subject.other	CMIP5 model simulation	en
dc.title	Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence	en
dc.type	Article	en
dc.type.version	publishedVersion	en
dcterms.bibliographicCitation.articlenumber	559337	en
dcterms.bibliographicCitation.doi	10.3389/feart.2020.559337	en
dcterms.bibliographicCitation.journaltitle	Frontiers in Earth Science	en
dcterms.bibliographicCitation.originalpublishername	Frontiers	en
dcterms.bibliographicCitation.originalpublisherplace	Lausanne	en
dcterms.bibliographicCitation.volume	8	en
tub.accessrights.dnb	free	en
tub.affiliation	Fak. 5 Verkehrs- und Maschinensysteme::Inst. Psychologie und Arbeitswissenschaft::FG Psychologie Neuer Medien und Methodenlehre	de
tub.affiliation.faculty	Fak. 5 Verkehrs- und Maschinensysteme	de
tub.affiliation.group	FG Psychologie Neuer Medien und Methodenlehre	de
tub.affiliation.institute	Inst. Psychologie und Arbeitswissenschaft	de
tub.publisher.universityorinstitution	Technische Universität Berlin	en