1. The ELF Characterization of the Earth – Ionosphere Cavity
Yurdanur Tulunay[1], Yıldırım Bahadırlar[2],
Emre Altuntaş[3], Ersin Tulunay[4],[2]
[1] METU/ODTÜ, Dept. of Aerospace Eng., Ankara, Turkey
[2] TÜBİTAK / MAM Institute of Information Technologies, Gebze Kocaeli, Turkey
[3] METU/ODTÜ, Dept. of Aerospace Eng., Ankara, Turkey
[4] METU/ODTÜ, Dept. of Electrical and Electronics Eng., Ankara, Turkey
COST 724 MCM, Antalya, TURKEY, March 2006

2. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Content
Introduction,
Objectives & Experimental Sites,
Data Analysis,
Preliminary Results
Future Study
COST 724 MCM, Antalya, TURKEY, March 2006

3. Introduction- II SR occur in the Earth – Ionosphere Cavity
λ ≈ 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:
COST 724 MCM, Antalya, TURKEY, March 2006

4. 7.8; 14; 20; 26; 33; 39 and 45 Hz Introduction- I
Observed Frequencies:
7.8; 14;
20; 26;
33; 39 and 45 Hz
COST 724 MCM, Antalya, TURKEY, March 2006

5. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Objectives - I
SR Spectral characteristics:
Resonant mode amplitude, A (mV^2)
Center frequency, f (Hz),
Q – Factor, f/width (unitless)
COST 724 MCM, Antalya, TURKEY, March 2006

6. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Objectives - II
Diurnal variations of SR Characteristics :
Two measurement sites;
GÖNEN (40o 06’ N 27o 38’ E)
ŞARKÖY (40o 50’ N 27o 08’ E)
COST 724 MCM, Antalya, TURKEY, March 2006

7. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Measurement Sites
COST 724 MCM, Antalya, TURKEY, March 2006

8. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Measurement Sites
Şarköy
Gönen
COST 724 MCM, Antalya, TURKEY, March 2006

9. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Data Analysis - I
Raw data in time domain
BP filtered
October, 2004 Data
FFT Analysis
...
Sample Data: Şarköy Oct , 00:00
COST 724 MCM, Antalya, TURKEY, March 2006

10. Data Analysis - II 6 Lorenzian functions of the form;
Lorentz Curve Fit
(Price et al. 2004)
COST 724 MCM, Antalya, TURKEY, March 2006

11. Results – I (Diurnal var. of each 4 Mode Power)
COST 724 MCM, Antalya, TURKEY, March 2006

12. Results – II (Diurnal var. of each Mode Peak Freq.s)
COST 724 MCM, Antalya, TURKEY, March 2006

13. Results – III (Diurnal var. of each 3 Mode Q-Fac.)
COST 724 MCM, Antalya, TURKEY, March 2006

14. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
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.
COST 724 MCM, Antalya, TURKEY, March 2006

15. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
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 and SHatori 1996)
Q-Factor variations; complex characteristics,
in agreement with (Price et al and SHatori 1996)
COST 724 MCM, Antalya, TURKEY, March 2006

16. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Future Work
Turkish SR Results will be:
Input METU NN Neural Network
Forecasting of Future SR Parameters
COST 724 MCM, Antalya, TURKEY, March 2006

17. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
Acknowledgement
Thanks to
COST 724
TUBITAK MAM
TUBITAK ÇAYDAG
COST 724 MCM, Antalya, TURKEY, March 2006

18. COST 724 MCM, Antalya, TURKEY, 27-30 March 2006
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 resonances—II. Daily and seasonal
frequency variations. Journal of Atmospheric and Terrestrial Physics 5,
1483–1488., 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,
15973–15984., 1991.
[5]
COST 724 MCM, Antalya, TURKEY, March 2006