Fig. 4From: Kalmag: a high spatio-temporal model of the geomagnetic fieldTime series between 1900 and 2022 of selected spherical harmonics coefficients (indicated on the top of each panel) of the secular variation at the Earth’s surface. \(68.2\%\) confidence interval of the Kalmag solution (red areas) and the COV-OBS.x2 solution (blue areas) of Huder et al. (2020)Back to article page