University of Oulu

Väisänen, P., Usoskin, I., & Mursula, K. (2017). Structure of the Power Spectral Density of Galactic Cosmic Ray Variation during 1953-2016. Proceedings of the International Astronomical Union, 13(S335), 82-86. doi:10.1017/S1743921317010122

Structure of the power spectral density of galactic cosmic ray variation during 1953-2016

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Author: Väisänen, Pauli1; Usoskin, Ilya1; Mursula, Kalevi1
Organizations: 1Space Climate Research Unit, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
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Language: English
Published: Cambridge University Press, 2017
Publish Date: 2018-08-22


Fluxes of galactic cosmic rays (GCR) observed at 1 AU are modulated inside the heliosphere at different time scales. Here we study the properties of the power spectral density (PSD) of galactic cosmic ray variability using hourly data from 31 neutron monitors (NM) from 1953 to 2016. We pay particular attention to the reliability of the used datasets and methods. We present the overall PSD and discuss different parts of the spectrum and the related periodicities. We find significant spectral peaks at the periods of 11 years, 1.75 years, 155 days, 27 days and 24 hours and the harmonics of the latter two peaks. We calculate a power law slope of −1.79 ± 0.13 for the period range between 50 and 130 hours and a slope of −1.34 ± 0.17 for the period range between 40 days and 3.4 years (1000 − 30000 h).

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Series: Proceedings of the International Astronomical Union
ISSN: 1743-9213
ISSN-E: 1743-9221
ISSN-L: 1743-9213
Pages: 82 - 86
DOI: 10.1017/S1743921317010122
Host publication: Proceedings IAU Symposium No. 335, 2017. Space Weather of the Heliosphere: Processes and Forecasts. 17-21 July, University of Exeter, United Kindom
Host publication editor: Foullon, Claire
Malandraki, Olga E.
Conference: Symposium of the International Astronomical Union
Type of Publication: A4 Article in conference proceedings
Field of Science: 115 Astronomy and space science
Funding: We acknowledge the financial support by the Academy of Finland to the ReSoLVE Centre of Excellence (project no. 272157).
Academy of Finland Grant Number: 272157
Detailed Information: 272157 (Academy of Finland Funding decision)
Copyright information: © International Astronomical Union 2018.