Figure 9
From: The BGS magnetic field candidate models for the 12th generation IGRF
Spectral power per degree extracted from parent model at yearly intervals from 2009.5 to 2014.5. The plots show the spectra for the main field (top), secular variation (middle), and secular acceleration (bottom). The effect of temporal damping is visible in the smooth, monotonically decreasing behaviour of the higher-degree secular variation and secular acceleration power.