Table 6 Number N, Huber-weighted mean, and standard deviation \(\sigma\) computed from the residuals of the monthly ground observatory SV data for each component and split into polar (poleward \(\pm 55^{\circ }\)) and non-polar (equatorward \(\pm 55^{\circ }\)) QD latitudes
Dataset | Quasi-dipole latitude | Component | N | Mean (nT/yr) | \(\sigma\) (nT/yr) |
|---|---|---|---|---|---|
Observatories | Non-polar | \({\dot{B}}_r\) | 11348 | 0.20 | 2.09 |
\({\dot{B}}_\theta\) | 11348 | − 0.18 | 2.26 | ||
\({\dot{B}}_\phi\) | 11348 | 0.06 | 2.43 | ||
Polar | \({\dot{B}}_r\) | 3609 | 0.22 | 4.43 | |
\({\dot{B}}_\theta\) | 3609 | − 0.19 | 4.21 | ||
\({\dot{B}}_\phi\) | 3609 | − 0.08 | 2.85 |