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Condensation nuclei events at 30 km and possible influences of solar cosmic rays

Naturevolume 302pages511514 (1983) | Download Citation



Two recent observations have provided the basis for study of a relationship between solar activity and the formation of small particles in the Earth's atmosphere: the discovery of annual increases of condensation nuclei (CN) at 30 km (refs 1–3) and the detection of sulphuric acid molecules in large negative ion clusters in the 25–35-km altitude region4–7. These observations have now led us to formulate and test a model wherein CN are formed in a ‘polar cloud chamber’ supersaturated with sulphuric acid vapour and triggered by ionization associated with solar flare cosmic radiation. We conclude that such a model provides a potential explanation of the observations.

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  1. 1

    Rosen, J.M. & Hofmann, D.J. Rep. Ap-08 (Dept of Physics & Astronomy, Univ. Wyoming, December, 1981).

  2. 2

    Hofmann, D. J. & Rosen, J. M. Nature 297, 120–125 (1982).

  3. 3

    Rosen, J.M. & Hofmann, D.J. J. geophys. Res. (in the press).

  4. 4

    Arnold, F. & Fabian, R. Nature 283, 55–57 (1980).

  5. 5

    Arnold, F. & Henschen, G. Geophys. Res. Lett. 8, 83–86 (1981).

  6. 6

    Arnold, F. Nature 299, 134–137 (1982).

  7. 7

    Arijs, E., Nevejans, D., Frederick, P. & Ingels, J. Geophys. Res. Lett. 8, 121–124 (1981).

  8. 8

    Rosen, J. M. & Hofmann, D. J. J. appl. Met. 16, 56–62 (1979).

  9. 9

    Rosen, J. M., Hofmann, D. J. & Kaselau, K. H. J. appl. Met. 17, 1737–1740 (1978).

  10. 10

    Hofmann, D. J. & Rosen, J. M. Rep. AP-73 (Dept. of Physics and Astronomy, Univ. Wyoming, August, 1982).

  11. 11

    Viggiano, A. A. & Arnold, F. Geophys. Res. Lett. 8, 583–586 (1981).

  12. 12

    Yue, G. K. & Hamill, P. J. Aerosol Sci. 10, 609–614 (1979).

  13. 13

    Hofmann, D. J. & Winckler, J. R. J. geophys. Res. 68, 2067–2098 (1963).

  14. 14

    Armstrong, T. P., Brungardt, C. & Meyer, J. Weather and Climate Reponses to Solar Variations (ed. McCormac, B. M.) (Colorado Associated University Press, 1982).

  15. 15

    Hofmann, D. J. & Rosen, J. M. Geophys. Res. Lett. (in the press).

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  1. Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming, 82071, USA

    • D. J. Hofmann
    •  & J. M. Rosen


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