North Atlantic climate variability from a self-organizing map perspective

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dc.contributor.authorReusch, David B
dc.contributor.authorAlley, Richard B
dc.contributor.authorHewitson, Bruce C
dc.date.accessioned2021-10-08T07:04:28Z
dc.date.available2021-10-08T07:04:28Z
dc.date.issued2007
dc.description.abstract[1] North Atlantic variability in general, and the North Atlantic Oscillation (NAO) in particular, is a long-studied, very important but still not well-understood problem in climatology. The recent trend to a higher wintertime NAO index was accompanied by an additional increase in the Azores High not coupled to changes in the Icelandic Low, as shown by a self-organizing maps (SOMs) analysis of monthly mean DJF mean sea level pressure data from 1957 to 2002. SOMs are a nonlinear tool to optimally extract a user-specified number of patterns or icons from an input data set and to uniquely relate any input data field to an icon, allowing analyses of occurrence frequencies and transitions complementary to principal component analysis (PCA). SOMs analysis of ERA-40 data finds a North Atlantic monopole roughly colocated with the mean position of the Azores High, as well as the well-known NAO dipole involving the Icelandic Low and the subtropical high. Little trend is shown in December, but the Azores High increased along with the NAO in January and February over the study interval, with implications for storminess in northwestern Europe. In short, our SOM-based analyses of winter MSLP have both confirmed prior knowledge and expanded it through the relative ease of use and power with nonlinear systems of the SOM-based approach to climatological analysis.
dc.identifier.apacitationReusch, D. B., Alley, R. B., & Hewitson, B. C. (2007). North Atlantic climate variability from a self-organizing map perspective. <i>Journal of Geophysical Research</i>, 112(D2), 174 - 177. http://hdl.handle.net/11427/34509en_ZA
dc.identifier.chicagocitationReusch, David B, Richard B Alley, and Bruce C Hewitson "North Atlantic climate variability from a self-organizing map perspective." <i>Journal of Geophysical Research</i> 112, D2. (2007): 174 - 177. http://hdl.handle.net/11427/34509en_ZA
dc.identifier.citationReusch, D.B., Alley, R.B. & Hewitson, B.C. 2007. North Atlantic climate variability from a self-organizing map perspective. <i>Journal of Geophysical Research.</i> 112(D2):174 - 177. http://hdl.handle.net/11427/34509en_ZA
dc.identifier.issn0022-1406
dc.identifier.issn0148-0227
dc.identifier.issn1934-2098
dc.identifier.issn2156-2202
dc.identifier.ris TY - Journal Article AU - Reusch, David B AU - Alley, Richard B AU - Hewitson, Bruce C AB - [1] North Atlantic variability in general, and the North Atlantic Oscillation (NAO) in particular, is a long-studied, very important but still not well-understood problem in climatology. The recent trend to a higher wintertime NAO index was accompanied by an additional increase in the Azores High not coupled to changes in the Icelandic Low, as shown by a self-organizing maps (SOMs) analysis of monthly mean DJF mean sea level pressure data from 1957 to 2002. SOMs are a nonlinear tool to optimally extract a user-specified number of patterns or icons from an input data set and to uniquely relate any input data field to an icon, allowing analyses of occurrence frequencies and transitions complementary to principal component analysis (PCA). SOMs analysis of ERA-40 data finds a North Atlantic monopole roughly colocated with the mean position of the Azores High, as well as the well-known NAO dipole involving the Icelandic Low and the subtropical high. Little trend is shown in December, but the Azores High increased along with the NAO in January and February over the study interval, with implications for storminess in northwestern Europe. In short, our SOM-based analyses of winter MSLP have both confirmed prior knowledge and expanded it through the relative ease of use and power with nonlinear systems of the SOM-based approach to climatological analysis. DA - 2007 DB - OpenUCT DP - University of Cape Town IS - D2 J1 - Journal of Geophysical Research LK - https://open.uct.ac.za PY - 2007 SM - 0022-1406 SM - 0148-0227 SM - 1934-2098 SM - 2156-2202 T1 - North Atlantic climate variability from a self-organizing map perspective TI - North Atlantic climate variability from a self-organizing map perspective UR - http://hdl.handle.net/11427/34509 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34509
dc.identifier.vancouvercitationReusch DB, Alley RB, Hewitson BC. North Atlantic climate variability from a self-organizing map perspective. Journal of Geophysical Research. 2007;112(D2):174 - 177. http://hdl.handle.net/11427/34509.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Environmental and Geographical Science
dc.publisher.facultyFaculty of Science
dc.sourceJournal of Geophysical Research
dc.source.journalissueD2
dc.source.journalvolume112
dc.source.pagination174 - 177
dc.source.urihttps://dx.doi.org/10.1029/2006JD007460
dc.subject.otherNon linear system
dc.subject.otherEurope
dc.subject.othersubtropical zone
dc.subject.otherDipole
dc.subject.otherPosition
dc.subject.otherMonopole
dc.subject.otherprincipal components analysis
dc.subject.otherOccurrence frequency
dc.subject.otherSea level pressure
dc.subject.otherMean sea level
dc.subject.othermonthly average
dc.subject.otherWinter
dc.subject.othertrend-surface analysis
dc.subject.otherDynamical climatology
dc.subject.otherNorth Atlantic oscillation
dc.subject.otherSelf-organising feature maps
dc.subject.otherAzores
dc.subject.otherNorth Atlantic
dc.subject.otherAtlantic Ocean Islands
dc.subject.otherAtlantic Ocean
dc.subject.otherSystème non linéaire
dc.subject.otherZone subtropicale
dc.subject.otherDipôle
dc.subject.otherMonopôle
dc.subject.otherAnalyse composante principale
dc.titleNorth Atlantic climate variability from a self-organizing map perspective
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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