Fig. 9From: COV-OBS.x2: 180 years of geomagnetic field evolution from ground-based and satellite observationsMF (left) and SV (right) Lowes spectra (Eq. (3)) at the Earth’s surface for epochs 2015, 2020 and 2025, estimated with the spline-free BLUE (see Methods). In dashed lines the respective spectra for the \(\pm \sigma \) spread within the ensemble of modelsBack to article page