Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.585 IF 1.585
  • IF 5-year value: 1.698 IF 5-year
    1.698
  • CiteScore value: 1.62 CiteScore
    1.62
  • SNIP value: 0.820 SNIP 0.820
  • IPP value: 1.52 IPP 1.52
  • SJR value: 0.781 SJR 0.781
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 83 Scimago H
    index 83
  • h5-index value: 24 h5-index 24
Volume 20, issue 2
Ann. Geophys., 20, 175–183, 2002
https://doi.org/10.5194/angeo-20-175-2002
© Author(s) 2002. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 20, 175–183, 2002
https://doi.org/10.5194/angeo-20-175-2002
© Author(s) 2002. This work is distributed under
the Creative Commons Attribution 3.0 License.

  28 Feb 2002

28 Feb 2002

Nonlinear time series analysis of the fluctuations of the geomagnetic horizontal field

B. George1, G. Renuka1, K. Satheesh Kumar2, C. P. Anil Kumar3, and C. Venugopal4 B. George et al.
  • 1Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala - 695 581, India
  • 2Department of Mathematics, St. John’s College, Anchal PO, Kerala - 691 306, India
  • 3School of Pure and Applied Physics, Mahatma Gandhi University, Priyadarshini Hills PO, Kottayam, Kerala - 686 560, India
  • 4Department of Physics, University of Asmara, PO Box 1220, Eritrea
  • Correspondence to: G. Renuka (dlcampus@vsnl.com)

Abstract. 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)

Publications Copernicus
Download
Citation