A relationship between the life of M-regions and the rate of change of solar activity

Abstract

To test the hypothesis that the observed lack of success in forecasting disturbances to radio propagation by using the recurrence pattern during the 1953–1954 sunspot minimum period is due to the high rate of decay of the 1947–1954 cycle of solar activity, magnetic character figures for the period 1890–1950 were examined. A numerical definition of “persistence of recurrence” s given and a linear relationship is obtained between the maximum value of this quantity at sunspot minimum and the rate of decay of solar activity to that minimum. The extremely low value of this quantity predicted by this relationship for the 1954 sunspot minimum period is considered to provide confirmatory evidence for the initial hypothesis.