BEXCO - Room F(201/202/203/204)
[SH067] On selected quasi-periodicities in neutron monitor data
- Mária KANCÍROVÁ
- Mária KANCÍROVÁ (Nuclear Physics Institute of the CAS, Czech Republic)
Quasi-periodic signals in cosmic ray intensity as measured on the ground by neutron monitors have been studied over long time. Using fast Fourier transform and wavelet technique we present results on the quasi-biennal and on shorter periodicity contributions to the time series in barometric pressure corrected data from ground based measurements, especially from neutron monitors Hermanus, Oulu, Roma, Huancayo and Haleakala. Appearance of Rieger-type periodicity, transitional waves in the range above ~ 27 days as well as solar diurnal variation and its higher harmonics are reported during several solar cycles. Features in the changes of contribution of various waves to the power spectra of cosmic ray are discussed in the frame of knowledge of cosmic ray modulation in the inner heliosphere.