Forecast of the most geomagnetically disturbed days

Abstract

Perturbed periods characterized by the AA* index compiled from 1868 to 1992 are considered. Our analysis of the geomagnetic activity is done by considering the even-odd effect, that was observed in the maximum solar activity and applying Gumbel's first asymptotic distribution extreme values. The present study shows that the largest geomagnetically perturbed days should have different intensities depending on the parity of the solar cycles in which they occur.