Fig. 1.
From: Wavelet-based multiscale analysis of geomagnetic disturbance
Fourier power spectra of the geomagnetic variations displaying a scaling behaviour. Top: increasing phase (left), decreasing phase (middle) and year 2001 (right). Bottom: July 2000 (left). October 2003 (middle) and November 2003 (right) obtained at the three observatories. The straight lines are the linear least-squares fit. The slope of the regression line, indicated on each plot, reveals the global exponent β.