Analysis of geomagnetic pulsations using multiwavelets spectral and polarization method

In this paper, we present an algorithm based on the multi-wavelet transform and on the multitaper spectral and polarization methods to estimate polari zation parameters of a non-stationary geomagnetic pulsations signals. Throu gh the first right-singular vector and the singular values, obtained from s ingular value decomposition (SVD) of the multiwavelet eigenspectra matrix M (f, t) of the three-component geomagnetic pulsations we determined the pola rization parameters of the hydromagnetic waves in the time-frequency plane. It was used in the multiwavelet polarization analysis to estimate the pola rization parameters of geomagnetic pulsations signals obtained from a large geomagnetic storm on March 24, 1991. The results showed that this method i s a powerful tool to find events with high degree of polarization and allow to determine the polarization parameters continually in both time and freq uency, giving an appropriate resolution to study pulsations that have narro w spectral band and short-lived components. (C) 2000 Elsevier Science B.V. All rights reserved.