On Diurnal Variation in Cosmic-Ray Intensity
- James A. Van Allen
Published Online: 20 MAR 2013
Copyright 1993 American Geophysical Union.
Cosmic Rays, the Sun and Geomagnetism: The Works of Scott E. Forbush
How to Cite
Forbush, S. E. (1993) On Diurnal Variation in Cosmic-Ray Intensity, in Cosmic Rays, the Sun and Geomagnetism: The Works of Scott E. Forbush (ed J. A. Van Allen), American Geophysical Union, Washington, D. C.. doi: 10.1029/SP037p0119
- Published Online: 20 MAR 2013
- Published Print: 1 JAN 1993
Print ISBN: 9780875908335
Online ISBN: 9781118667996
- Cosmis ray variations;
- Solar activity;
Cosmic-ray data from precision cosmic-ray meter records obtained at Cheltenham, Maryland, for 273 complete days during April 1935 to October 1936 are subjected to rigorous statistical analysis. The results indicate that the real barometric coefficient does not change from hour to hour or from month to month. It is shown that the barometric coefficient obtained at this station is in good agreement with certain results obtained from altitude-intensity curves. It is furthermore shown, in two independent ways, that there is no indication of any external air-temperature effect upon the recorded intensity. Finally, the data have been subjected to modern statistical methods which provide an objective measure for the probability that the observed diurnal-variation is real. The results indicate, for the period covered by this analysis, a physically significant 24-hour wave in apparent cosmic-ray intensity, with an amplitude of 0.17 per. cent of the total intensity having its maximum at about 11h, 75° west meridian mean time.