Fig. 6

Power spectra (PS) of the modeled \({B}_{r}^{\mathrm{harmonic}-\mathrm{spike}}\) over the Earth’s surface every 100 years. In pink-red lines, the PS before (1150 BC) and during LIAA maximum (1050 BC–850 BC) are plotted. In green-yellow the PS after LIAA maximum (750 BC–450 BC). The grey dash line shows the mean power spectrum during the whole period