Fig. 13.
From: Evaluation of candidate geomagnetic field models for IGRF-11
Rate of change of the axial dipole (in units of nT/yr) from model GRIMM-2 (bars showing formal error estimates), along with a maximum entropy fit and extrapolation (red). A 50 year model derived from observatory monthly means (labelled Obs. SV. Model) constructed by Lesur and Wardinski (2009) is shown in stars to illustrate the rate of change prior to the validity of GRIMM-2. The remaining symbols show the predictions of the IGRF-11 SV candidates plotted for their central epoch of 2012.5.