ANNUAL AND SEMIANNUAL VARIATIONS OF THE COSMIC-RADIATION

The annual and semi-annual harmonics in the Deep River Neutron Monitor counting rate for the years 1960-1975 are determined. A new Fourier analysis technique is used to eliminate solar cycle variations, and the statistical errors in the determination of the harmonics are discussed. The annual and semiannual waves change markedly from year to year. The yearly harmonic has an average amplitude similar 0. 6% with a maximum in early March, corresponding to a southward anisotropy of similar 5%/AU perpendicular to the solar equatorial plane. The semiannual hamonic shows no phase coherence and its average amplitude is only marginally significant, less than equivalent to 0. 2%.