Fig. 9.

Power spectral analysis and degree coherence between the ‘true’ and the estimated lithospheric field models. Left: power spectrum of the ‘true’ model (black), the estimated model without polar gap treatment (red), and the estimated model with the polar gap processing (blue). The spatial power spectrum of the difference between both types of models and the ‘true’ one are also shown. Middle: Spherical Harmonic Correlation Analysis between the ‘true’ model and the model estimated with (blue) and without (red) polar gap post-processing. The dashed vertical line indicate SH degree 133. Right: Azimuthal power spectrum of the ‘true’ model (black) and the model estimated with (blue) and without (red) polar post-processing.