Multipole Analysis. II. Geomagnetic Secular Variation

Abstract

The method of multipole analysis described in Part I is applied to the Earth's magnetic field for various epochs between 1845 and 1965, allowing the geomagnetic secular variation to be illustrated by time trends in the multipole parameters. The rates of change of the multipole parameters are used to separate the secular variation into non.drifting, meridional drifting, and longitudinal drifting components, which are discussed in detail for the epoch 1965.