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Ann. Geophys., 14, 1513-1525, 1996
www.ann-geophys.net/14/1513/1996/
© European Geosciences Union 1996
Time-frequency tools of signal processing for EISCAT data analysis
J. Lilensten and P. O. Amblard
CEPHAG, URA 346, BP 46, 38402 St Martin d'hères Cedex, France
Abstract. We demonstrate the usefulness of some
signal-processing tools for the EISCAT data analysis. These tools are somewhat
less classical than the familiar periodogram, squared modulus of the Fourier
transform, and therefore not as commonly used in our community. The first is a
stationary analysis, "Thomson's estimate'' of the power spectrum. The other
two belong to time-frequency analysis: the short-time Fourier transform with the
spectrogram, and the wavelet analysis via the scalogram. Because of the highly
non-stationary character of our geophysical signals, the latter two tools are
better suited for this analysis. Their results are compared with both a
synthetic signal and EISCAT ion-velocity measurements. We show that they help to
discriminate patterns such as gravity waves from noise.
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