Audible Auroras - Observers

[A brilliant auroral storm]This picture of a particularly intense auroral storm is one of thousands of splendid photographs taken over a period of fifteen years by Jay Brausch of Glen Ullin, North Dakota.He attributes his success to the continued support from his parents, seen here in the foreground watching the display.

Jay's prize-winning work has been featured in publications such as "Weatherwise", "Horizon" and "Sky and Telescope". His night-by-night monitoring of the aurora is said to be the most complete survey of the morphology of auroral displays. During the day he checks sunspot activity, which often warns him when to expect a spectacular aurora.

Jay uses a Canon AE-1 35-mm camera with 50 mm lens and Kodacolor ASA 200 (for warm colors) or ASA 400 (for cold colors). He also takes pictures of lightning using a 28-80 mm zoom lens.

The sound of auroras is as elusive as the electrophonic sounds of bolides. Jay Brausch, who has witnessed the most intense displays, has never heard their eerie sounds! From interviews with those who have, they are somewhat similar to the signals picked up by ELF/VLF radio receivers, which is to be expected unless Keay's theory for their production is false.

Excellent examples of auroral radio signals have been obtained by Stephen McGreevy of the Physics Department, University of Iowa, who has designed and built a special radio receiver expressly for such signals in the ELF/VLF region of the spectrum. His McGreevy WR-4B E-field ELF/VLF receiver uses a 3-metre vertical antenna and feeds a Marantz PMD 212 3-head professional casette recorder. The sampling rate is 8-bit at 11 kHz.

A recording very similar in character to aural reports was obtained at 0730 PDT on 1993 August 18 from the Alvord Desert in south-east Oregon when a major magnetic storm was in progress. The recording consists of a distinct hiss with intrusions of dawn chorus and many sferics (sounding like "pops") from distant lightning.Geomagnetic micropulsations are very evident as slow undulations in the hiss every three or four seconds, as auroral ear-witnesses sometimes report.

Poetic descriptions of auroral sounds were gathered together by William Petrie, Assistant Chief Scientist, Defence Research Board, Ottawa, in his book "Keoeeit - The Story of the Aurora Borealis". The descriptions in the poetry and from people interviewed match very nicely the sounds on Steve McGreevy's tapes when the chirps of the dawn chorus and the lightning sferics are ignored.

Experience for yourself the evocative power of combined Auroral Sights, Sounds and Poems, but note this warning! The next page will require downloading a 375-kilobyte .WAV file, which may take a considerable time.Further hint: don't have the sound turned up too loud, it ruins the eerie effect!