Lightning Observations in Finland and Theoretical Calculation of the Lightning Electromagnetic Pulse

  • T. J. Tuomi
  • T. H. Summanen
  • R. J. Pirjola


This paper deals with lightning observations made in Finland by lightning flash counters for thirty years and by an LLP lightning location system since 1984. Estimation of flashes per unit area based on counter data cannot yet be performed since the operational range of the counters is unknown, being somewhere between 17 and 45 km. The counters seem to record more flashes than the LLP system does. A reason could be the low conductivity of the earth in Finland, which might deform the electromagnetic signal emitted by a lightning stroke too much during the propagation to pass the acceptance criteria of the LLP system. Signals incident on a LLP direction finder have been recorded, and theoretical calculations were started. The latter work also discussed in this paper has, however, so far only concerned a perfectly conducting earth thus giving no answer to the question of the effect of the low conductivity.


Current Pulse Electromagnetic Signal Transmission Line Model Return Stroke Lightning Flash 
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  1. 1.
    Laitinen L (1976) Lightning flash counter activity in Finland 1961…1975. CIGRE-document 33–76 (TF 33-01.01) 16 IWD, Paris, France, August 1976, 10 pp.Google Scholar
  2. 2.
    Laitinen L (1985) Salamanlaskijatoiminta Suomessa vuosina 1961–1980 (Lightning counters in Finland during the period 1961–1980). (Finnish with an English abstract), Sahko-Electricity in Finland 58, 4: 18–20Google Scholar
  3. 3.
    Laitinen L. Leino K. Palva V (1971) Lightning flash counter measurements in Finland 1961…1970. Sahko-Electricity in Finland 44, 9: 215–222Google Scholar
  4. 4.
    Pirjola R (1978) Lightning flash counter activity in Finland 1961…1975. URSI XIX General Assembly, Helsinki, Finland, Session El, 1.8. 1978, 9 pp.Google Scholar
  5. 5.
    Tuomi TJ (1987) Lightning observations in Finland 1984–1986. Geophysical Publications, Finnish Meteorological institute, No. 4, 47 pp.Google Scholar
  6. 6.
    Tuomi TJ (1988) Lightning observations in Finland 1987. Geophysical Publications Finnish Meteorological Institute, No. 5, 37 pp.Google Scholar
  7. 7.
    Tuomi TJ (1989) Lightning observations in Finland, 1988. Geophysical Publications, Finnish Meteorological Institute, No. 8, 34 pp.Google Scholar
  8. 8.
    Tuomi TJ (1989) Lightning observations in Finland, 1989. Geophysical Publications, Finnish Meteorological Institute, No. 11, 39 pp.Google Scholar
  9. 9.
    Tuomi TJ (1989) Salamanpaikantimen paikannusvirheet (Location errors of the lightning location system). (Finnish with an English abstract). In: Forsius J (ed): Proceedings of XIV Geofysiikan paivat, Helsinki, Finland, May 3–5, 1989, Geophysical Society of Finland: 67–71Google Scholar
  10. 10.
    Koskenniemi O. Laiho J (1975) Measurements of effective ground conductivity at low and medium frequencies in Finland. E.B.U. Review - Technical Part, Technical Centre of the European Broadcasting Union, 153, 4 pp.Google Scholar
  11. 11.
    Fine H (1954) An Effective Ground Conductivity Map for Continental United States. Proceedings of the IRE 42: 1405–1408CrossRefGoogle Scholar
  12. 12.
    Uman MA (1977) Calculation of the Electric and Magnetic Fields Produced by Close Lightning. In: Dolezalek H. Reiter R (eds): Electrical Processes in Atmospheres, Proceedings of the Fifth International Conference on Atmospheric Electricity held at Garmisch-Partenkirchen, West Germany, 2–7 September, 1974, Dr. Dietrich Steinkopff Verlag, Darmstadt: 597–606Google Scholar
  13. 13.
    Summanen T (1988) Salaman aiheuttaman sahkokentan teoreettinen mallintaminen (= Theoretical modelling of the electric field caused by lightning). (Finnish). Thesis for the M.Sc. degree, Department of Theoretical Physics, University of Helsinki, Finland, 78 pp.Google Scholar
  14. 14.
    Le Vine DM. Gessel L (1984) The influence of ground conductivity on the structure of RF radiation from return strokes. Preprint Proceedings of the VIIth International Conference on Atmospheric Electricity, Albany, New York, USA, June 3–8, 1984, American Meteorological Society: 401–406Google Scholar
  15. 15.
    Nucci CA. Rachidi F (1989) Experimental validation of a modification to the transmission line model for LEMP calculations. In: Dvorak T (ed): Proceedings of the 8th International Zurich Symposium and Technical Exhibition on Electromagnetic Compatibility, Zurich, Switzerland, 7–9 March, 1989, 76 M2: 389–394Google Scholar
  16. 16.
    Bruce CER. Golde RH (1941) The lightning discharge. The Journal of The Institution of Electrical Engineers 88, Part II (Power Engineering), 6: 487–520Google Scholar
  17. 17.
    Lindell IV. Alanen E (1984) Exact Image Theory for the Sommerfeld Half-Space Problem, Part III: General Formulation. IEEE Transactions on Antennas and Propagation AP-32, 10: 1027–1032Google Scholar

Copyright information

© Springer-Verlag Tokyo 1991

Authors and Affiliations

  • T. J. Tuomi
    • 1
  • T. H. Summanen
    • 1
  • R. J. Pirjola
    • 1
  1. 1.Geophysics DepartmentFinnish Meteorological InstituteHelsinkiFinland

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