Figure 8From: Geomagnetic observatory monthly series, 1930 to 2010: empirical analysis and unmodeled signal estimation Latitudinal variation of the annual and semiannual periodic signals amplitude. Amplitude of the annual (bottom) and semiannual (top) periodic signals for all three components of the magnetic field as a function of the geomagnetic latitude, averaged over the period 1960 to 2010, obtained for a window length of δ t=5 years.Back to article page