Observation of earth's orbital motion using cosmic-ray Compton-Getting effect at Matsushiro underground station
Abstract
Data observed at the Matsushiro underground station located at an effective vertical depth of 220 mwe underground for the period 1980-1990 are used to investigate the earth's motion Compton-Getting effect on the solar diurnal variation of cosmic ray intensity. The analysis is made for two periods of solar activity, the quiet period for averaged sunspot numbers less than 60 (1984-1988), and the active period (1980-1984 and 1988-1989). It is shown that, for the quiet period, the difference E-W diurnal vector has a phase of 22.5 +/-1.3 hr in LT and an amplitude of 0.030 +/-0.007 percent. With a clockwise rotation of this E-W vector by the right angle, it is compared with that expected from the earth's motion Compton-Getting effect. The observed and the expected vector are in fair agreement. For the active period, the observed E-W diurnal vector shows some contribution from the solar diurnal anisotropy, in addition to the Compton-Getting effect. It is inferred that for the last solar active period the upper cutoff energy of solar diurnal anisotrpy is as high as that for the threshold of 220 mwe depth underground.
- Publication:
-
Journal of Geomagnetism and Geoelectricity
- Pub Date:
- 1991
- DOI:
- 10.5636/jgg.43.771
- Bibcode:
- 1991JGG....43..771Y
- Keywords:
-
- Compton Effect;
- Diurnal Variations;
- Earth Motion;
- Solar Cosmic Rays;
- Sunspots;
- Anisotropy;
- Fourier Analysis;
- Muons;
- Solar Activity