Fig. 10
From: COV-OBS.x2: 180 years of geomagnetic field evolution from ground-based and satellite observations
Time evolution of the external dipole field coefficient in dipole coordinates (top: \(q_{1d}^0\)) and induced dipole field coefficient in geocentric coordinates (bottom: \(g_{1}^{0\dag }\)) for COV-OBS.x2 (black), compared with the previous edition COV-OBS.x1 (dashed blue), superimposed with the corresponding estimate from CHAOS-7 (gray, selected over calm magnetic times on the left column (see text for details) and for all times in the right column) and its projection onto splines with knots 2-year apart (orange)