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Titel |
Regional and inter-regional effects in evolving climate network |
VerfasserIn |
Jaroslav Hlinka, David Hartman, Nikola Jajcay, Martin Vejmelka, Reik Donner, Norbert Marwan, Jürgen Kurths, Milan Palus |
Konferenz |
EGU General Assembly 2014
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 16 (2014) |
Datensatznummer |
250097929
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Publikation (Nr.) |
EGU/EGU2014-13557.pdf |
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Zusammenfassung |
Real-world systems composed of many interacting subsystems are frequently studied as
complex networks. Studied systems are thus represented by graphs composed of nodes
standing for the subsystems and edges denoting interactions present among the nodes; the
characteristic properties of the graph are subsequently studied and related to the
system’s behavior. Potential time-dependency of edges is conveniently captured
in so-called evolving networks. There is a growing interest in the application of
complex network analysis approach to climate data. Use of evolving networks is a
promising technique in this research area due to non-stationarity of the climate
dynamics. Recently, it has been shown that an evolving climate network can be used
to disentangle different types of El-Nino episodes described in the literature. In
particular, an evolving network was constructed as thresholded correlation matrix of
a year-long daily surface air temperature data from the NCEP/NCAR reanalysis
dataset remapped onto a 10242-point equidistant geodesic grid. The time evolution of
several graph characteristics, including density, clustering coefficient or average path
length, has been compared with the intervals of El Niño and La Niña episodes. In the
current study we identify the sources of the evolving network characteristics by
considering a reduced-dimensionality description of the climate system. First, we have
used low density geodesic grid remapping as well as rotated principal component
analysis to define the network nodes. In a more detailed analysis, the uncovered
components were used to segment the whole globe surface into 68 regions. The time
evolution of temperature correlation structures in local intra-component networks
was studied and compared to evolving inter-component connectivity. This detailed
analysis showed that the evolution of graph properties of the global network can be
mostly attributed to the evolution of the intra-regional connectivity of the ENSO
area and adjacent tropical regions and of the inter-regional connectivity between
those. |
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