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ELF Radio Wave Database

Name of Database ELF Radio Wave Database
Institution Graduate School of Science, Tohoku University
Contents Tohoku University installed the ELF observation system at Syowa station, Antarctica in 2000 and carries out the continuous recording of 1-100 Hz waveforms in order to monitor the global lightning activity and to investigate the characteristics of lightning-related phenomena including high altitude discharges, such as sprites. Now we employ totally 4 sites for this purpose, namely, Onagawa (Japan), Kiruna (Sweden), California (US) and Syowa (Antarctica). This system is the only facility which records ELF waveforms continuously in the world. The data obtained provides essential information for environmental monitoring since it is recently pointed out that lightning activity would be a good quantitative proxy of atmospheric convections.
Examples Figure 1 shows an example of one-day dynamic spectra of magnetic field waveform data obtained at Syowa station in Antarctica on 14 January, 2003. Upper and lower panels represent the H- and D-component dynamic spectra, respectively. The harmonic structure of Schumann resonance waves up to the seventh are clearly seen at about 8, 14, 20, 26, 32, 39, and 45 Hz in both H- and D- component dynamic spectra. Spectral power enhancements are also seen in these spectra, which are strongly related with the global lightning activity.

Figure 1. Example of one-day dynamic spectra of ELF waveform data obtained at Syowa station
Contact Takahiro Obara and Hiroshi Fukunishi
Planetary Plasma and Atmospheric Research Center, Graduate School of Science, Tohoku University
Aramaki-aza-aoba, Aoba, Sendai, Miyagi, Japan 980-8578
TEL: +81-22-795-3499
FAX: +81-22-795-6406
T.Obara[AT]pparc.gp.tohoku.ac.jp
Public Offering of Database

As a trial manufacture edition of data plotting and database, the following web site is opened experimentally. Information such as the data acquisition day and simple plotting are added.

EDAC(ELF Data Archive Center) (http://edac.geophys.tohoku.ac.jp)


Figure 2. Entry page of the EDAC web site.

Figure 2 shows a picture of the entry page of the EDAC web site. The outline of the ELF observation system is also shown not only in this web page but also in the following references.

Sato, M., and H. Fukunishi, Global sprite occurrence locations and rates derived from triangulation of transient Schumann resonance events, Geophys. Res. Lett., 30(16), 1859, 2003.

Sato, M., H. Fukunishi, M. Kikuchi, H. Yamagishi, and W.A. Lyons, Validation of sprite-inducing cloud-to-ground lightning based on ELF observations at Syowa station in Antarctica, J. Atmos. Solar-Terr. Phys., 65, 607-614, 2003.
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