Russian Journal of Earth Sciences
Vol. 5, No. 5, October 2003
Wavelet analysis of secular geomagnetic variations
N. M. Rotanova, T. N. Bondar, and E. V. Kovalevskaya
Abstract
Temporal characteristics of secular variations ( SV ) over the last hundred of years are studied using
the wavelet transformation, providing estimates of dispersion and energy parameters
of the process analyzed.
The presence of abrupt geomagnetic field variations of the intraterrestrial origin
in periods of 1969-1970
and 1989-1990 is confirmed. The
SV process is, on the whole, nonfractal, and only two largest scales can
be regarded
as monofractal. The
SV scale diagrams obtained from the wavelet analysis not only revealed singularities
in the
SV field but also provided constraints on variations in its energy parameters
throughout the time interval studied.
On the basis of the
SV phase portrayal constructed in our study, the limits of the
SV dynamic system are estimated
to be
2