Table 1 (a), (b) Mean (\(\mu\)) and root-mean-square (\(\sigma\)) residuals (in nT) of the DIFI-2015b model in the domain of validity, \(|\theta _{qd}| \le 55^{\circ }\), for the radial (r), polar (\(\theta\)) and azimuthal (\(\phi\)) components. (c) Mean and root-mean-square differences (in nT) between predictions of the DIFI-2015b model and independent observations at the NCK and CBI observatories during quiet times (as defined for this study, see “Data preprocessing” section), for the same components

N

\(\mu _r\)

\(\sigma _r\)

\(\mu _{\theta }\)

\(\sigma _{\theta }\)

\(\mu _{\phi }\)

\(\sigma _{\phi }\)