Use of multidimentional MEM spectral analysis in geophysics

Auto and cross spectral analysis is the basic tool for geophysicist in order to study resonances of the magnetosphere using natural electromagnetic waves recorded in several places. The comparisons of these records must be made by autoregressive (AR) spectral estimators because the signal duration is short. For this application we show that the presentation of AR autospectrum by the position of the poles of the z transform is interesting. We make a direct comparison of the poles position for signal recorded at different places. Finally we present the influence of the choice of the order and discuss the particularities of the two dimensional autoregressive analysis.