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Two Classes of Auroral Infrasound at I53US

Two Classes of Auroral Infrasound at I53US. By Charles R. Wilson, John V. Wilson, Curt Szuberla and Daniel L.Osborne, Geophysical Institute, University of Alaska, Fairbanks AK. Huge AIW Bow Wave signal at I53US at 15:49 UT, 04/14/03 during magnetic storm.

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Two Classes of Auroral Infrasound at I53US

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  1. Two Classes of Auroral Infrasound at I53US By Charles R. Wilson, John V. Wilson, Curt Szuberla and Daniel L.Osborne, Geophysical Institute, University of Alaska, Fairbanks AK

  2. Huge AIW Bow Wave signal at I53US at15:49 UT, 04/14/03 during magnetic storm Trace velocity = 0.602 km/s, Az = 276 deg, Cij = 0.916

  3. Uncertainty in Vel and Theta for AIW at I53US April 14,2003,(Dr.Curt Szuberla) Vel = 614 m/sec +/- 60 m/sec Azimuth = 276.5 +/- 5.8 deg. Uncertainty Ellipse in Velocity Space

  4. Three component Magnetometer traces at Fairbanks April 14, 2003 Strong magnetic bay at 12:00 to 16:00 UT Time of Huge AIW

  5. All-SKY camera images at 30 second intervals at Fairbanks Zenith crossing At 09:51 UT AIW – Bow wave at 09:59 UT

  6. Bow Wave model for AIW signals fromsupersonic aurora electrojet arcs

  7. (I53US) Inuvik N.W.T. Auroral Oval Azimuths of arrival of AIW at each hour of UT at I53US Direction of supersonic motion of Source auroral arcs for AIW as a Function of UT time

  8. AIW signals MCCM Trace velocity Azimuth of arrival April 14,2003 auroral infrasound event of AIW Bow-Wave Type

  9. Vel = 1.03 km/s AZ = 347 deg. Vel = 0.875 AZ = 316 Vel = 0.643 AZ = 283 Vel = 0.871 AZ = 280 April 14, 2003 AIW associated with auroral-electrojet supersonic motions

  10. Azimuth versus Trace velocity In meters/sec AIW Bow Wave Signals Mean trace velocity for Bow Wave AIW Signals is = 0.865 km/sec

  11. New Type of Pulsating Aurora AIW • Pulsating Aurora • An Example of a Typical All Sky TV Camera Capture of Pulsating Aurora. Image Circle Is About 160 Degrees Edge to Edge (fisheye lens). Images are played in real speed, at 15 fps, the B&W image utilizes all visible light.

  12. Pulsating Aurora from GI/UA’s Ester Dome Observatory East West North

  13. Three images of pulsating Aurora patches above I53US On March 6, 2003 , images taken At 20 second intervals at 12:25 to 12:26 UT

  14. Vel = 1.213 Az = 144 deg Peak-to-peak amplitude = 0.3 Pascal I53US Pulsating Aurora Infrasound March 06, 2003, 12:25 to 12:43 UT

  15. abs(fft) March 6 P-AIW signal 44.8 sec 32.2 sec 20.8 sec

  16. Vel = 1.517 km/sec Az = 202 deg. P-AIW from March 06, 2003 at I53US 16:00 to 16:20 UT

  17. MCCM detector output for March 6, 2003at I53US showing both MAW from 180 degand high velocity P-AIW signals from all azimuths MCCM High Velocity P-AIW signals MAW signals Velocity Azimuth MAW signals

  18. East South North West

  19. MAW at I53US 03/06/2003 20:00 to 20:20 UT March 6,2003, 20:00 to 20:20 UT Simultaneous MAW Event Velocity = 0.497 km/sec, Az = 181

  20. Trace velocity m/sec versus Azimuth for MAW And for high velocity P-AIW signals 06/03/2003 MAW P-AIW P-AIW

  21. Other high velocity infrasound putative pulsating aurora events • Two examples, on Dec 15 and 25, 2002 at I53US,of infrasonic signals during magnetic storm/auroral events with the same signal characteristics of very high trace velocity, widely scattered azimuth of arrival, and similar spectra. There was no photographic aurora data available of visible pulsating auroral patches during these two events.

  22. 15 December Phase-aligned 0verlay All 8 sensors

  23. abs(fft) Dec 15 P-AIW signal 41.5 sec 31.2 sec 25.4 sec 17.5 sec

  24. Uncertainty in Velocity and Azimuth for highvelocity auroral infrasound event Dec 15,2002 Vel = 2.941 km/sec +/- 0.938 km/sec Azimuth = 130 +/- 17 deg. Uncertainty Ellipse in Velocity Space

  25. MCCM Trace Velocity Km/sec Azimuth

  26. East South North West

  27. Phase-Aligned Pulsating Aurora Infrasound I53US 12/15/02twenty minutes of data at 12,15,18 and 21 hours UT Vel = 3.35 km/sec Az =127 Vel = 5.26 km/s Az = 171 Vel = 1.48 km/s Az = 229 Vel = 1.00 km/s Az = 129

  28. Auroral Infrasound signal azimuths observed at Pullman Washington, Boulder Colorado and Washington DC Thousands of kilometers away from the source region

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