The explanation of some covariances, associated with the Backus effect, in the طrsted model (9/99)

It is shown that comparatively large covariances between some of the coefficients produced in a spherical harmonic analysis of the geomagnetic field result from the use of scalar (intensity) data in a situation in which the field is approximately that of an inclined dipole. As with the Backus effect, such correlations are reduced as relatively more vector data is used.