ITW2007 Infra-red image of a typhoon (by JMA) Mt. Anatahan eruption ( ) photo by Patrick Shore Total eclipse 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 Installed To be Installed Tbilisi Alibag Phimai Aso Kyoto Magnetometer only Inikli Barometric Observation Urumqi Inchuan Kashi Magnetometer planning Geomagnetic pulsation at Sumatra Earthquake. (Iyemori et al., GRL, 2005) Vertical Wind Ionospheric Dynamo J=VxB 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 (Kanamori, 2004) Acoustic cutoff frequency Brunt-Vaisala frequency Acoustic wave Internal gravity wave (4 5 minutes) Dispersion diagram of acoustic gravity waves Vph Phase velocity Fast Slow Acoustic cutoff frequency a : a = g/2c C 2 = RT Wave reflection at cutoff frequency Resonance between ground and ionospheric height Vertical resonance Period (min.) Altitude (km) 270sec=4.5min229sec=3.8min196sec=3.3min (K. Nishida, 2000) 200km 100km 0km Principal modes of acoustic resonance 01:12UT Magnetic data TEC data Earthquake Oscillations in the ionosphere excited at Sumatra earthquake TEC Pulsation Magnetic Pulsation Resonance peak at a period of 3.6min. Shinagawa et al. (EPS, 2007) 3 resonance modes Two dimensional simulation of acoustic wave resonance in realistic atmosphere with geomagnetic field at 120km (ionosphere) 3 major resonance frequency mHz ( min., sec.) mHz ( min., sec.) mHz ( min., 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 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 Typhoon No :00UT (GMS Satellite) Typhoon No.14 Pressure at SGA and Mag-D at Aso (11-12LT) Mag-D at ASO Pressure at SGA Period (min.) Typhoon No.14 Pressure at Shigaraki and Mag-H at Aso (12-13LT) Mag-H at Aso Pressure at SGA Typhoon No.14 Pressure at SGA and Mag-D at ASO (14-15LT ) Pressure at SGA Mag-D at ASO Period (min) Typhoon No.14 Pressure at SGA and Mag-H at Aso ( LT) Mag-H at ASO Pressure at SGA 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 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 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? Magnetic oscillation could be more uniform than that of pressure Investigation of acoustic resonance with geomagnetic data Ionospheric current Dynamo Electric field 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=VxB 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. Tong Hai Onset of another Pulsation (01:11UT) Lower atmosphere Space ? (Appendix) 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 03:19 M5.4 01:0002:0003:0004:00 GPS-TEC Pulsation after the Earthquake on Dec. 26, 2004 Universal Time (hour) 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 02486 Universal Time (02UT) DPRI Shigaraki Kyoto Univ. Location and Sensor of barometer ACE Solar wind data (9/21-9/23) and AE indices (9/22) Very low geomagnetic activity throughout the day Barometric oscillation at Shigaraki A case of Typhoon ( ) Magnetic oscillation at Aso (D-comp.) Mag-H at ASO Pressure at SGA Pressure at ASO 1. Resonance