Skip to main content

Development of an automatic procedure to estimate the reflection height of tweek atmospherics


This paper presents an automated procedure to estimate apparent reflection height h (from the cutoff frequency for the first waveguide mode, fc), horizontal propagation distance d, and propagation time Tg of tweek atmospherics. Tweek data recorded at the Kagoshima Observatory (31.48°N, 130.72°E), Japan, were used to evaluate the procedure by comparing the results estimated by the automatic method to those read manually by an operator. The two types of results showed differences (automatic–manual) of +0.58 km, −9.9 Hz, and +3058.9 km for mean h, fc, and d, respectively. The difference in h(fc) was less than the resolution of the fast Fourier transform used to obtain the tweek spectra. These comparisons indicate that the automatic estimation procedure of tweek parameters developed in this paper performs well and is a useful tool for studying long-term height variations of the ionospheric D and lower E regions using very low frequency (VLF) and extremely low frequency (ELF) records observed in Japan over the past 30 years.


  • Bickel, J. E., J. A. Ferguson, and G. V. Stanley, Experimental observation of magnetic field effects on VLF propagation at night, Radio Sci., 5, 19, 1970.

    Article  Google Scholar 

  • Christian, H. J., R. J. Blakeslee, D. J. Bocchippio, W. L. Boeck, D. E. Buechler, K. T. Driscoll, S. J. Goodman, J. M. Hall, W. J. Koshak, D. M. Mach, and M. F. Stewart, Global frequency and distribution of lightnings as observed from space by the Optical Transient Detector, J. Geophys. Res., 108, ACL4–1–ACL4–15, 2003.

    Google Scholar 

  • Davies, K., Ionospheric Radio Waves, Waltham, MA: Blaisdell, 1969.

    Google Scholar 

  • Ferencz, O. E., Short impulse propagation in waveguides, Hiradastechnika “Communications”, LIX, 6, 2–6, 2004.

    Google Scholar 

  • Ferencz, O. E., Cs. Ferencz, P. Steinbach, J. Lichtenberger, D. Hamar, M. Parrot, F. Lefeuvre, and J.-J. Berthelier, The effect of subiono-spheric propagation on whistlers recorded by the DEMETER satellite—observation and modeling, Ann. Geophys., 25, 1103–1112, 2007.

    Article  Google Scholar 

  • Hayakawa, M., K. Ohta, and K. Baba, Wave characteristics of tweek atmospherics deduced from the direction-finding measurement and theoretical interpretation, J. Geophys. Res., 99, 10733–10743, 1994.

    Article  Google Scholar 

  • Hayakawa, M., K. Ohta, S. Shimakura, and K. Baba, Recent findings on VLF/ELF sferics, J. Atmos. Terr. Phys., 57, 467–477, 1995.

    Article  Google Scholar 

  • Holdsworth, D. A., R. Vuthaluru, I. M. Reid, and R. A. Vincent, Differential absorption measurements of mesospheric and lower thermospheric electron densities using the Buckland Park MF radar, J. Atmos. Terr. Phys., 64, 2029–2042, 2002.

    Article  Google Scholar 

  • Lynn, K. J. and J. Crouchley, Night-time sferic propagation at frequencies below 10 kHz, Aust. J. Phys., 20, 101–108, 1967.

    Article  Google Scholar 

  • Maeda, K.-I., Study on electron density profile in the lower ionosphere, J. Geomag. Geoelectr., 23, 133–159, 1971.

    Article  Google Scholar 

  • Ohya, H., M. Nishino, Y. Murayama, and K. Igarashi, Equivalent electron densities at reflection heights of tweek atmospherics in the low-middle latitude D-region ionosphere, Earth Planets Space, 55, 627–635, 2003.

    Article  Google Scholar 

  • Ohya, H., M. Nishino, Y. Murayama, K. Igarashi, and A. Saito, Using tweek atmospherics to measure the response of the low-middle latitude D-region ionosphere to a magnetic storm, J. Atmos. Solar-Terr. Phys., 68, 697–709, 2006.

    Article  Google Scholar 

  • Outsu, J., Numerical study of tweeks based on waveguide mode theory, Proc. Res. Inst. Atmos., Nagoya University, 7, 58–71, 1960.

    Google Scholar 

  • Shvets, A. V. and M. Hayakawa, Polarization effects for tweek propagation, J. Atmos. Solar-Terr. Phys., 60, 461–469, 1998.

    Article  Google Scholar 

  • Thomas, L. and M. D. Harrison, The electron density distributions in the D-region during the night and pre-sunrise period, J. Atmos. Terr. Phys., 32, 1–14, 1970.

    Article  Google Scholar 

  • Thomson, N. R., Experimental daytime VLF ionospheric parameters, J. Atmos. Terr. Phys., 55, 173–184, 1993.

    Article  Google Scholar 

  • Tohmatsu, T., Compendium of Aeronomy (translated and revised by T. Ogawa), Terra Scientific Pub. and Kluwer, 1990.

    Google Scholar 

  • Yamashita, M., Propagation of tweek atmospherics, J. Atmos. Terr. Physics, 40, 151–153, 1978.

    Article  Google Scholar 

  • Wait, J. R., Electromagnetic Waves in Stratified Media, Pergamon, New York, 1972.

    Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Hiroyo Ohya.

Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit

Reprints and permissions

About this article

Cite this article

Ohya, H., Shiokawa, K. & Miyoshi, Y. Development of an automatic procedure to estimate the reflection height of tweek atmospherics. Earth Planet Sp 60, 837–843 (2008).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

Key words