1. ITW2007 Infra-red image of a typhoon (by JMA) Mt. Anatahan eruption (2003.05.11) photo by Patrick Shore Total eclipse 2006.03.29 Photo by Katsuya Ishikawa Atmosphere-Ionosphere- Magnetosphere coupling Detection of Vertical Resonance Modes of Acoustic Waves and Its Confirmation With Geomagnetic Field Measurement T. Iyemori 1 ; M. Matsumura 1 ; H. Shinagawa 2 ; M. Nose 1 ; M. Hashizume 3 ; T. Tanaka 4 ; D.-S. Han 5 ; N. Oshiman 6 ; M.K. Tuncer 7 ; A. Saito 1 ; M. Utsugi 1 ; Y. Odagi 1 ; N. Arai 8 [1] Graduate School of Science, Kyoto Univ.; [2] NICT ; [3] Churalongkorn Univ.; [4]Setsunan Univ.; [5] Polar Research Institute of China; [6] DPRI, Kyoto Univ.; [7] KOERI, Bogazici University; [8] JWA

2. Installed To be Installed Tbilisi Alibag Phimai Aso Kyoto ▲ ▲ ▲ Magnetometer only Inikli Barometric Observation Urumqi Inchuan △ Kashi △ Magnetometer planning

3. Geomagnetic pulsation at Sumatra Earthquake. (Iyemori et al., GRL, 2005) Vertical Wind  Ionospheric Dynamo J=σVxB  geomagnetic pulsation Sumatra earthquake caused lower atmospheric disturbances, which generate geomagnetic pulsations through acoustic wave resonance between the Earth's surface and thermosphere (i.e., ionospheric dynamo by the vertical wind.) To confirm this scenario, we have made comparative observation with barometer and magnetometer Ionosphere 01:0002:00 nT

4. (Kanamori, 2004) Acoustic cutoff frequency Brunt-Vaisala frequency Acoustic wave Internal gravity wave (4 ～ 5 minutes) Dispersion diagram of acoustic gravity waves

5. Vph Phase velocity Fast Slow Acoustic cutoff frequency ω a : ω a = γg/2c C 2 = γRT Wave reflection at cutoff frequency  Resonance between ground and ionospheric height Vertical resonance Period (min.) Altitude (km)

6. 270sec=4.5min229sec=3.8min196sec=3.3min (K. Nishida, 2000) 200km 100km 0km Principal modes of acoustic resonance

7. 01:12UT Magnetic data ＧＰＳ TEC data Earthquake Oscillations in the ionosphere excited at Sumatra earthquake “TEC Pulsation” Magnetic Pulsation Resonance peak at a period of 3.6min.

8. Shinagawa et al. (EPS, 2007)  3 resonance modes Two dimensional simulation of acoustic wave resonance in realistic atmosphere with geomagnetic field at 120km (ionosphere)

9. 3 major resonance frequency 3.7-3.8 mHz (4.4-4.5 min., 260-270 sec.) 4.4-4.6 mHz (3.6-3.8 min., 210-230 sec.) 5.0-5.1 mHz (3.2-3.3 min., 190-200 sec.) Geomagnetic pulsation at Mt. Pinatubo eruption. Mt. Pinatubo eruption Total eclipse on March 29, 2006  4.4min  3.7 min Total eclipse  Inicli (Turkey), Urumqi (China) and Aso (Japan)  How about pressure?  Same frequency ?  Cases of typhoon ? Other cases

10. Our Barometric Observation Sites Sensor of barometer (VAISALA PTB210) 0.01hPa (0.0025hPa A/D) DC ～ 1Hz 1 sec recording (499Hz sampling) Aso Kyoto Uji Shigaraki ～ 500km (Geomagnetic data are also available at Aso and Shigaraki) ▲ ▲ Magnetometer only Mineyama

11. Typhoon No.14 2006.09.22 03:00UT (GMS Satellite)

12. Typhoon No.14 Pressure at SGA and Mag-D at Aso (11-12LT) Mag-D at ASO Pressure at SGA Period (min.)

13. Typhoon No.14 Pressure at Shigaraki and Mag-H at Aso (12-13LT) Mag-H at Aso Pressure at SGA 周期（分）

14. Typhoon No.14 Pressure at SGA and Mag-D at ASO (14-15LT ) Pressure at SGA Mag-D at ASO Period (min)

15. Typhoon No.14 Pressure at SGA and Mag-H at Aso (15.5-16.5LT) Mag-H at ASO Pressure at SGA

16. A comparison of barometric oscillation at Uji,Shigaraki and Isumi High-pass filtered data Power spectra Uji Shigaraki Isumi 11:0014:00 Period (minutes) Local Time

17. A comparison after an Earthquake near Shigaraki, Japan Shigaraki is close to epicenter ( ～ 30km) and amplitude of pressure oscillation is large. (Origin time=12:19LT, M=5) Pressure at Shigaraki Mag.(D) at Aso Pressure at Aso

18. SUMMARY (1) 1.Spectral peaks in both pressure and geomagnetic fields at acoustic resonant frequencies (3 – 4 minutes) often appear and agree with theoretical prediction.  Lower atmosphere – ionosphere coupling  Confirmation of “acoustic resonance” 2. Spectral peaks of pressure and those of magnetic field often coincide even if they apart more than 500km. They are intermittent and the peak frequency varies.  Magnetic oscillation (i.e., ionospheric current) is coherent in wider area because of its electro-magnetic nature ?  Many independent sources of resonance exist?

19. Magnetic oscillation could be more uniform than that of pressure  Investigation of acoustic resonance with geomagnetic data Ionospheric current Dynamo Electric field

20. SUMMARY (2) 3. The acoustic resonance and generation of magnetic pulsation through ionospheric dynamo seem to be a rather common phenomenon. 4. Not only the acoustic resonance but also atmospheric internal gravity waves at lower frequencies (5-7 minutes) seem to cause geomagnetic pulsations. But having no specific (i.e., “resonant”) frequency. 5. A possible route of energy transfer from lower atmospheric disturbances to plasma space through ionospheric dynamo. ( J=σVxB dynamo  E, J  ExB drift, JxB force, Joule heating, etc. ) 6. Micro-barometric observation and magnetic observation seem to be a beneficial combination each other in both scientific and practical (i.e. observational) sense.

21. Tong Hai  Onset of another Pulsation (01:11UT) Lower atmosphere  Space ?

22. (Appendix)

23. Barometric Oscillation ＝ Local turbulence + Acoustic wave (resonance) ＋ Gravity wave Geomagnetic Oscillation = Geomagnetic pulsation (magnetospheric origin) + Ionospheric dynamo current (oscillation) How to detect these minor components? Basic characteristics of micro-barometric variations

24. 03:19 M5.4

26. 01:0002:0003:0004:00 GPS-TEC Pulsation after the Earthquake on Dec. 26, 2004 Universal Time (hour)

27. A comparison after an Earthquake near Shigaraki, Japan Shigaraki is close to epicenter ( ～ 30km) and amplitude of pressure oscillation is large. (Origin time=12:19LT, M=5) Pressure at Shigaraki Mag.(D) at Aso Pressure at Aso

28. 02486 Universal Time 地震発生時刻 スマトラ沖地 震 タイ・ピマー イ 磁場観測

29. 地震発生直前１時間後 (02UT) ２時間後 ３時間後４時間後 ５時間後

31. DPRI Shigaraki Kyoto Univ. Location and Sensor of barometer

32. ACE Solar wind data (9/21-9/23) and AE indices (9/22) Very low geomagnetic activity throughout the day

33. Barometric oscillation at Shigaraki  A case of Typhoon (2006.09.22)  Magnetic oscillation at Aso (D-comp.)

34. Mag-H at ASO Pressure at SGA Pressure at ASO

35. 1. Resonance