Two examples of longer-period amplitude variations present in these data. Top panels: spectral-time plots constructed using Stokes-V data in the same spectral window as plotted in the left-hand panel of Fig. 2. Bottom panels: variation in B_SFA over time calculated from the Stokes-V data plotted in the top panels. Peak-to-peak amplitude variations are measured to be more than 400 G in both of these cases.