Fig. 11From: Geomagnetic Virtual Observatories: monitoring geomagnetic secular variation with the Swarm satellitesFour-monthly Core Field SV GVOs mapped to Earth’s surface (red symbols) with \(\pm \sigma\) uncertainties, and 4-monthly revised means from selected polar ground observatories (black symbols), left column: Resolute Bay (Canada), middle column: Macquarie Island (Australia), right column: Mawson Station (Antarctica). Top row is the radial field component, middle row is the southward field component, bottom row is the eastward field component, units are nTBack to article page