抄録
This paper briefly describes the application of the cross-spectrum analysis technique by multichannel maximum entropy method (MULMEN) to the study of medium-scale traveling ionospheric disturbances (MS-TID) detected with an array of HF Doppler receivers in central Japan during MAP period.
Experiments with artificial data have shown that the MULMEM technique provides by far better spectral estimates than the traditional technique of Blackman-Tukey using FFT algorithm. Several fundamental wave parameters of the TID were then calculated as a function of time by the MULMEM technique. We find that the dynamical (spectral peak traced) multiplet structure of the wave parameters can be well resolved. It is exemplified that such resolution is utilized not only to estimate the number of simultaneous excitation sources but also to detect on occasion the temporal variation in the velocity dispersion of the MS-TID.
