Small-scale cosmic-ray fluctuations and their association with recurrent phenomena, October 1965 through April 1966

A method is developed for separating the diurnal variation from cosmic-ray data recorded by NM64 neutron monitors at high latitudes. It utilizes the negligible diurnal variation at the Alert station, which is verified by power spectrum analysis. The method offers the development of a "universal high-latitude diurnal wave" on a day-to-day basis, taking into account the asymptotic longitude differences between the stations.The period 15 October 1965 to 30 April 1966 is studied in connection with the space measurements of Pioneer VI.