Table 5 Comparison of models with secular variation data derived from 99 ground observatories equatorward of \(\pm 40^{\circ }\) QD latitude during the gap period between CHAMP and Swarm (19 September 2010 to 22 November 2013)
From: Co-estimation of geomagnetic field and in-orbit fluxgate magnetometer calibration parameters
N | mean (nT/year) | \(\sigma\) (nT/year) | median (nT/year) | MAD (nT/year) | |
|---|---|---|---|---|---|
Model A | |||||
\(dB_r/dt\) | 44 710 | 0.46 | 4.28 | 0.33 | 3.70 |
\(dB_{\theta }/dt\) | 44 710 | 0.21 | 9.11 | 0.79 | 8.69 |
\(dB_{\phi }/dt\) | 44 677 | 0.24 | 6.12 | 0.08 | 4.56 |
Model C | |||||
\(dB_r/dt\) | 44 710 | 0.37 | 5.26 | 0.44 | 4.50 |
\(dB_{\theta }/dt\) | 44 710 | 0.35 | 9.43 | 0.84 | 8.85 |
\(dB_{\phi }/dt\) | 44 677 | 0.36 | 6.29 | 0.20 | 4.82 |
Model D | |||||
\(dB_r/dt\) | 44 710 | 0.30 | 5.59 | 0.21 | 5.11 |
\(dB_{\theta }/dt\) | 44 710 | 0.37 | 10.65 | 0.73 | 10.62 |
\(dB_{\phi }/dt\) | 44 677 | 0.38 | 6.31 | 0.26 | 4.85 |
Model E | |||||
\(dB_r/dt\) | 44 710 | − 0.50 | 7.82 | − 1.16 | 7.11 |
\(dB_{\theta }/dt\) | 44 710 | 0.55 | 10.14 | 0.83 | 10.03 |
\(dB_{\phi }/dt\) | 44 677 | 0.85 | 7.25 | 0.76 | 5.91 |