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A Lunar-Month Modulation of Large Solar-Terrestrial Disturbances

Published online by Cambridge University Press:  25 April 2016

S. F. Smerd*
Affiliation:
Division of Radiophysics, CS1RO, Sydney

Extract

Dodson and Hedeman discovered an unexpected effect in the occurrence of solar proton events as revealed by polarcap absorption (PCA). When the 48 events in Bailey’s Catalog of the Principal PCA Events, 1952-1963 are distributed with the phase of the moon there is a gap of several days near full moon; also, many more events occur when the moon waxes than when it wanes. Dodson and Hedeman did not find similar, apparent departures from random distribution either with a mean solar rotation period of 27.3 days or for solar flare events. They concluded that ‘at the present time it is not clear whether the 29.5 day “effect” is related to the sun or the moon or is only a statistical accident’.

Type
Contributions
Copyright
Copyright © Astronomical Society of Australia 1967

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References

1 Dodson, Helen W., and Hedeman, E. Ruth, J. Geophys. Res., 69, 3965 (1964).CrossRefGoogle Scholar
2 Bailey, D. K., Planet. Space Sci., 12, 495 (1964).CrossRefGoogle Scholar
3 Kundu, M. R., ‘Solar Radio Astronomy’, p. 561, Interscience Publishers, New York, 1965.Google Scholar
4 Basler, R. P., and Owren, L., University of Alaska, Geophys. Inst., Scientific Report UAG-R152 (1964).Google Scholar
5 Jonah, F. C., Dodson-Prince, , Helen, , and Hedeman, , Ruth, E., ‘Solar Activity Catalogue’, Vols. 1 to 5, Table VIII, NASA, Houston, Texas (1964-65).Google Scholar