Solar Physics

, Volume 157, Issue 1–2, pp 375–387 | Cite as

Aspects of the long-term cosmic-ray modulation

I.Solar-cycle ascending phases and associated green corona features
  • M. Storini
  • O. Borello-Filisetti
  • V. Mussino
  • M. Parisi
  • J. Sýkora


To investigate the long-term modulation of galactic cosmic rays at the ground-based detector energies, the monthly values of the neutron monitor (Climax, Mt. Washington, Deep River, and Huancayo) and ionization chamber (Cheltenham/Fredericksburg, Huancayo, and Yakutsk) intensities have been correlated with the sunspot numbers (used as a proxy index for transient solar activity) for each phase of sunspot cycles 18 to 22. Systematic differences are found for results concerning odd and even sunspot cycles. During odd cycles (19 and 21) the onset time of cosmic-ray modulation is delayed when compared with the onset time of the sunspot cycle, while they are more similar during even (18, 20, and 22) cycles. Checking the green corona data, on a half-year basis, we found typical heliolatitudinal differences during ascending phases of consecutive sunspot cycles. This finding suggests a significant role of the latitudinal coronal behaviour in the heliospherical dynamics during a Hale cycle. Such effectiveness concerns not only the transient interplanetary perturbations but also the recurrent ones. In fact, when lag between cosmic-ray data and sunspot numbers is considered, the anticorrelation between both parameters is very high (correlation coefficient |r| > 0.9) for all the phases considered, except for the declining ones of cycles 20 and 21, when high-speed solar wind streams coming from coronal holes affect the cosmic-ray propagation, and theRz parameter is no longer the right proxy index for solar-induced effects in the interplanetary medium.


Coronal Hole Sunspot Number Neutron Monitor Sunspot Cycle Solar Wind Stream 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bachelet, F., Iucci, N., Parisi, M., and Villoresi, G.: 1971,Report CNR/LPS-71-7, Laboratorio di Ricerca e Tecnologia per lo Studio del Plasma nello Spazio, Roma.Google Scholar
  2. Bachelet, F., Iucci, N., Villoresi, G., and Sporre, B.: 1972a,Il Nuovo Cimento 713, 17.Google Scholar
  3. Bachelet, F., Iucci, N., Villoresi, G., and Zangrilli, N.: 1972b,Il Nuovo Cimento 11B, 1.Google Scholar
  4. Bercovitch, M.: 1967,Proc. 10th Int. Cosmic Ray Conf., Calgary, Invited Talks, p. 269.Google Scholar
  5. Borello-Filisetti, O., Mussino, V., Parisi, M., and Storini, M.: 1992,Ann. Geophys. 10, 668.Google Scholar
  6. Cooper, J. F. and Simpson, J. A.: 1979,Proc. 16th Int. Cosmic Ray Conf., Kyoto 12, 176.Google Scholar
  7. Forbush, S. E.: 1954,J. Geophys. Res. 59, 525.Google Scholar
  8. Harman, C. V. and Hatton, C. J.: 1968,Can. J. Phys. 46, S1052.Google Scholar
  9. Jokipii, J. R., Levy, E. H., and Hubbard, W. B.: 1977,Astrophys. J. 213, 861.Google Scholar
  10. McKinnon, J. A. (revised by): 1987, Report UAG-95, World Data Center A for Solar-Terrestrial Physics, Boulder, Colorado.Google Scholar
  11. Moraal, H.: 1975,Proc. 14th Int. Cosmic Ray Conf., Münich 11, 3896.Google Scholar
  12. Morishita, I. and Nagashima, K.: 1993,Proc. 23rd Int. Cosmic Ray Conf, Calgary 3, 571.Google Scholar
  13. Nagashima, K., Sakakibara, S., Murakami, K., and Morishita, I.: 1989,Il Nuovo Cimento 12C, 173.Google Scholar
  14. Parisi, M., Storini, M., Borello-Filisetti, O., Mussino, V., and Sýkora, J.: 1992, in S. Fischer and M. Vandas (eds.),Proc. of the First SOLTIP Symposium, Astron. Institute of the Czechoslovak Academy of Science, Prague, Vol. 2, p. 159.Google Scholar
  15. Popielawska, B.: 1992,Planetary Space Sci. 40, 811.Google Scholar
  16. Popielawska, B. and Simpson, J. A.: 1990, in S. Grzedzielski and D. E. Page (eds.),Physics of the Outer Heliosphere, Pergamon Press, Oxford, p. 133.Google Scholar
  17. Potgieter, M. S.: 1994, in D. A. Leahy, R. B. Hicks, and D. Venkatesan (eds.),Proc. 23rd Int. Cosmic Ray Conf., Invited, Rapporteur and Highlight Papers, World Sci. Publ. Co., p. 213.Google Scholar
  18. Shea, M. A.: 1971,Proc. 12th Int. Cosmic Ray Conf., Hobart 3, 859.Google Scholar
  19. Shea, M. A. and Smart, D. F.: 1985,Proc. 19th Int. Cosmic Ray Conf., La Jolla 4, 501.Google Scholar
  20. Shea, M. A. and Smart, D. F.: 1990,J. Geomag. Geolectr. 42, 1107.Google Scholar
  21. Solar Geophysical Data: 1993, NOAA, U.S. Department of Commerce, Boulder, Colorado, Monthly Reports.Google Scholar
  22. Storini, M.: 1989,Ann. Geophys., Special Issue for the EGS-XIV General Assembly, p. 232.Google Scholar
  23. Storini, M.: 1990,Il Nuovo Cimento 13C, 103.Google Scholar
  24. Storini, M.: 1991,Il Nuovo Cimento 14C, 211.Google Scholar
  25. Storini, M., Borello-Filisetti, O., Mussino, V., and Parisi, M.: 1990,Rev. Bras. de Geofisica 8, 53.Google Scholar
  26. Storini, M., Sýkora, J., Felici, A., Bavassano, B., and Parisi, M.: 1994, in V. Rušin, P. Heinzel, and J.-C. Vial (eds.),Proc. IAU Colloq. 144, on Solar Coronal Structures, VEDA Publ. House of the Slovak Academy of Sciences, Bratislava, p. 143.Google Scholar
  27. Sýkora, J.: 1971,Bull. Astron. Inst. Czech. 22, 12.Google Scholar
  28. Sýkora, J.: 1992,Contr. Astron. Obs. Skalnaté Pleso 22, 55.Google Scholar
  29. Van der Walt, A. J. and Stoker, P. H.: 1990,J. Geophys. Res. 95, 209.Google Scholar
  30. Venkatesan, D. and Badruddin: 1990,Space Sci. Rev. 52, 121.Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • M. Storini
    • 1
  • O. Borello-Filisetti
    • 2
  • V. Mussino
    • 2
  • M. Parisi
    • 3
  • J. Sýkora
    • 4
  1. 1.Cosmic Ray SectionI.F.S.I./C.N.R., c/o Department of Physics, La Sapienza UniversityRomeItaly
  2. 2.Department of Physics-PolitecnicoTurinItaly
  3. 3.III University of Rome, c/o Department of Physics, La Sapienza UniversityRomeItaly
  4. 4.Slovak Academy of SciencesAstronomical InstituteTatranská LomnicaSlovak Republic

Personalised recommendations