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| Titel |
Nonlinear time series analysis of the fluctuations of the geomagnetic horizontal field |
| VerfasserIn |
B. George, G. Renuka, K. Satheesh Kumar, C. P. Anil Kumar, C. Venugopal |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 20, no. 2 ; Nr. 20, no. 2, S.175-183 |
| Datensatznummer |
250014353
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| Publikation (Nr.) |
 copernicus.org/angeo-20-175-2002.pdf |
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| Zusammenfassung |
A detailed nonlinear time
series analysis of the hourly data of the geomagnetic horizontal intensity H
measured at Kodaikanal (10.2° N; 77.5° E; mag: dip 3.5° N) has been carried
out to investigate the dynamical behaviour of the fluctuations of H. The
recurrence plots, spatiotemporal entropy and the result of the surrogate data
test show the deterministic nature of the fluctuations, rejecting the
hypothesis that H belong to the family of linear stochastic signals. The
low dimensional character of the dynamics is evident from the estimated value
of the correlation dimension and the fraction of false neighbours calculated
for various embedding dimensions. The exponential decay of the power spectrum
and the positive Lyapunov exponent indicate chaotic behaviour of the underlying
dynamics of H. This is also supported by the results of the comparison
of the chaotic characteristics of the time series of H with the
pseudo-chaotic characteristics of coloured noise time series. We have also
shown that the error involved in the short-term prediction of successive values
of H, using a simple but robust, zero-order nonlinear prediction method,
increases exponentially. It has also been suggested that there exists the
possibility of characterizing the geomagnetic fluctuations in terms of the
invariants in chaos theory, such as Lyapunov exponents and correlation
dimension. The results of the analysis could also have implications in the
development of a suitable model for the daily fluctuations of geomagnetic
horizontal intensity.
Key words. Geomagnetism and
paleomagnetism (time variations, diurnal to secular) – History of geophysics
(solar-planetary relationships) Magnetospheric physics (storms and substorms) |
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