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dc.contributor.authorSheshadri, Aditi
dc.contributor.authorPlumb, Raymond Alan
dc.date.accessioned2018-04-06T14:21:01Z
dc.date.available2018-04-06T14:21:01Z
dc.date.issued2017-04
dc.date.submitted2017-01
dc.identifier.issn0022-4928
dc.identifier.issn1520-0469
dc.identifier.urihttp://hdl.handle.net/1721.1/114585
dc.description.abstractThe two leading empirical orthogonal functions (EOFs) of zonal-mean zonal wind describe north-south fluctuations, and intensification and narrowing, respectively, of the midlatitude jet. Under certain circumstances, these two leading EOFs cannot be regarded as independent but are in fact manifestations of a single, coupled, underlying mode of the dynamical system describing the evolution in time of zonal wind anomalies. The true modes are revealed by the principal oscillation patterns (POPs). The leading mode and its associated eigenvalue are complex, its structure involves at least two EOFs, and it describes poleward (or equatorward) propagation of zonal-mean zonal wind anomalies. In this propagating regime, the principal component (PC) time series associated with the two leading EOFs decay nonexponentially, and the response of the system to external forcing in a given EOF does not depend solely on the PC decorrelation time nor on the projection of the forcing onto that EOF. These considerations are illustrated using results from an idealized dynamical core model. Results from Southern Hemisphere ERA-Interim data are partly consistent with the behavior of the model's propagating regime. Among other things, these results imply that the time scale that determines the sensitivity of a model to external forcing might be different from the decorrelation time of the leading PC and involves both the rate of decay of the dynamical mode and the period associated with propagation. Keywords: Annular mode; Atmospheric circulation; Dynamicsen_US
dc.description.sponsorshipSimons Foundation (Award 354584)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant OCE-1338814)en_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1175/JAS-D-16-0291.1en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Meteorological Societyen_US
dc.titlePropagating Annular Modes: Empirical Orthogonal Functions, Principal Oscillation Patterns, and Time Scalesen_US
dc.typeArticleen_US
dc.identifier.citationSheshadri, Aditi, and R. Alan Plumb. “Propagating Annular Modes: Empirical Orthogonal Functions, Principal Oscillation Patterns, and Time Scales.” Journal of the Atmospheric Sciences 74, 5 (May 2017): 1345–1361 © 2017 American Meteorological Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciencesen_US
dc.contributor.mitauthorPlumb, Raymond Alan
dc.relation.journalJournal of the Atmospheric Sciencesen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dc.date.updated2018-03-30T17:46:38Z
dspace.orderedauthorsSheshadri, Aditi; Plumb, R. Alanen_US
dspace.embargo.termsNen_US
dc.identifier.orcidhttps://orcid.org/0000-0002-6716-1576
mit.licensePUBLISHER_POLICYen_US


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