The ELF Characterization of the Earth

1
The ELF Characterization of the Earth
Ionosphere Cavity

• Yurdanur Tulunay1, Yildirim Bahadirlar2,
• Emre Altuntas3, Ersin Tulunay4,2

1 METU/ODTÜ, Dept. of Aerospace Eng., 06531
Ankara, Turkey 2 TÜBITAK / MAM Institute of
Information Technologies, Gebze Kocaeli,
Turkey 3 METU/ODTÜ, Dept. of Aerospace Eng.,
06531 Ankara, Turkey 4 METU/ODTÜ, Dept. of
Electrical and Electronics Eng., 06531 Ankara,
Turkey
2
Content

• Introduction,
• Objectives Experimental Sites,
• Data Analysis,
• Preliminary Results
• Future Study

3
Introduction- II
SR occur in the Earth Ionosphere Cavity
? 40 000 km
Main source for variations SR amplitudes
global lightning
activity SR frequency variations
of thunderstorm (Nickolaenko and Rabinowicz,
1995 Nickolaenko et al., 1998).
Fig. 1. Sources and Formation of Schumann
Resonances Reference http//www.iihr.uiowa.edu/pr
ojects/schumann/Index.html
4
Introduction- I

• Observed Frequencies
• 7.8 14
• 20 26
• 33 39 and 45 Hz

5
Objectives - I

• SR Spectral characteristics
• Resonant mode amplitude, A (mV2)
• Center frequency, f (Hz),
• Q Factor, f/width (unitless)

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Objectives - II

• Diurnal variations of SR Characteristics
• Two measurement sites

GÖNEN (40o 06 N 27o 38 E)
SARKÖY (40o 50 N 27o 08 E)
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Measurement Sites
8
Measurement Sites
Sarköy
Gönen
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Data Analysis - I

• Raw data in time domain
• BP filtered
• October, 2004 Data
• FFT Analysis
• ...

Sample Data Sarköy Oct. 01 2004, 0000
10
Data Analysis - II

• 6 Lorenzian functions of the form

Lorentz Curve Fit
(Price et al. 2004)
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Results I (Diurnal var. of each 4 Mode Power)
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Results II (Diurnal var. of each Mode Peak
Freq.s)
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Results III (Diurnal var. of each 3 Mode Q-Fac.)
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Conclusions - I

• Presented the SR Parameters observed in Turkey,
• One month period (October 2004).
• The three parameters of the SR spectra
• amplitude, frequency and damping
• obtained fitting the data with 6 Lorenzian
  curves.

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Conclusions - II

• The power (amplitude2) variations during the day
• maximum at 1400 LT,
• frequency power
• The frequency variations complex charact.,
• in agreement with (Price et al. 2004 and
  SHatori 1996)
• Q-Factor variations complex characteristics,
• in agreement with (Price et al. 2004 and
  SHatori 1996)

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Future Work
Turkish SR Results will be
Input METU NN Neural Network
Forecasting of Future SR Parameters
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Acknowledgement

• Thanks to
• COST 724
• TUBITAK MAM
• TUBITAK ÇAYDAG

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References
1 Price C., Melnikov A., Diurnal, seasonal and
inter-annual variations in the Schumann
resonance parameters, Journal of Atmospheric and
Solar- Terrestrial Physics, Vol 66, pp.
1179 1185, 2004 2 Resonances in
Earth-Ionosphere Cavity, Nickolaenko A.P.,
Hayakawa M., Kluver Academin Publishers,
Dordrecht/Boston/London, 2002. 3 SHatori, G.,
Monitoring Schumann resonancesII. Daily and
seasonal frequency variations. Journal of
Atmospheric and Terrestrial Physics 5,
14831488., 1996 4 Sentman, D.D., Fraser,
B.J., Simultaneous observations of Schumann
resonances in California and Australia evidence
for intensity modulation by the local
height of D region. Journal of Geophysical
Research 96, 1597315984., 1991. 5
http//www.iihr.uiowa.edu/projects/schumann/Index.
html