Topic: Researchers Create Acoustic 'Image' of Thunder

[miraculon]

I saw this in the NASA Tech Briefs about an acoustic signature of thunder.

http://www.techbriefs.com/component/content/article/1198-ntb/news/news/22108

More info here: http://www.swri.org/9what/releases/2015/thunder-image.htm#.VVUMMraoqfO

Southwest Research Institute (SwRI) researchers have imaged the first acoustic signature of thunder, visually capturing the sound waves created by artificially triggered lightning.

While the general mechanics of thunder generation are understood, it is not particularly clear which physical processes of the lightning discharge contribute to the thunder we hear.

By studying the acoustic power radiated from different portions of the lightning channel, researchers can learn more about the origins of thunder as well as the energetic processes associated with lightning.

Dr. Maher A. Dayeh, a research scientist in the SwRI Space Science and Engineering Division, designed a large, sophisticated array of microphones to study the acoustic signature of thunder. Fifteen microphones, spaced one meter apart, were lined up 95 meters away from the rocket launch pad where the triggered lightning would strike. To image the vertical profile of the bolt, Dayeh used post-signal processing techniques and directional amplification of the data signals captured by the microphone array.

The technique revealed a distinct signature of thunder generated by the lightning strike. Future experiments could allow scientists to study the probable acoustic signatures of current pulses, step leader branches, and discharge channel zigzags independently.

Start building your microphone arrays.....   

Greg H.

[Dr Obbins]

Start building your microphone arrays.....   

Greg H.

Yea.. Like we don't already have issues with our webcams and neighbors 

[WeatherHost]

What I'm reading is that this is a computer generated image of a studio type recording of artificial thunder.

[miraculon]

What I'm reading is that this is a computer generated image of a studio type recording of artificial thunder.

The "artificially triggered" refers to the lightning. University of Florida has a lightning research facility where they can induce strikes with rockets that have a trailing wire. I have seen photos and videos of this triggered lightning. They probably did this so they didn't have to wait for a "natural" strike.

There was a lot of post-processing of the sound recordings, but they captured the actual thunder with the microphone array.

Greg H.