Fig. 5From: Physics-based secular variation candidate models for the IGRFLowes–Mauersberger spectra of the variance of a series of secular variation models constructed sequentially between 2001.0 and 2010.0, by Kalman filtering, using an analysis step of one year, and all the satellite data available over the period. The SV is assumed constant over each interval of width one year. The variances are the diagonal coefficients of the posterior covariance matrix generated by the Kalman analysis step (no sequential smoothing is performed). See text for detailsBack to article page