The 24-Hrs Averages of Cosmic Ray Intensity in Stockholm 1947–48 and 1954

Abstract

Curves are given showing the variation of the 24-hrs averages of the C.R. intensity as measured by means of directional counter telescopes during two registration periods separated by six years. During both periods the maximum deviations were 2–3 per cent. In accordance with the view expressed by Simpson (1954) the periods of maximum are to be regarded as recurrent rather than being a harmonic function of time. There are some traces of a 27-day component having an amplitude of ± 0.4 per cent. The C.R. intensity as a function of time is compared to the solar cycles, the relative sun-spot number, the sun-spot area and the Kp-index.