1997 Volume 49 Issue 2-3 Pages 207-227
The method of natural orthogonal components (NOC) analysis, which separates temporal variations, and spherical harmonic analysis, which models spatial distribution, were combined to model the spatial-temporal variations of the geomagnetic field over the globe. NOC's obtained in this way describe the temporal variations year by year without smoothing. Use of combined observatory and satellite magnetic survey data for developing a spatial-temporal model of equal accuracy on the globe and over the time interval of the data is proposed.