Infrasound

[Bonzo]

I am wondering whether it would be useful to add an infrasound detector to the Blitzortung System.

Obviously it could register the sound of thunder of a local thunderstorm and add some time information. At least for regions with high station density.

But moreover, there seems to be a correlation of infrasound and the appearance of sprites. [1]

So, to register pulse profiles of the EM wave in conjunction with the infrasound profiles would add a fundamental research experiment to the system.

The sensor could be realized by means of so-called microbarometers. That has to be evaluated. Also the effect of interferers like wind turbines en stuff.

This is just an idea, not a proposal.

What do you think, it this interesting? Feasable? Desirable? Are there people out there that have the skills (and interest) to add according algorithms to the existing software?

Or is that completely out of interest for this project?

BTW: I am connected with the LOFAR radiotelescope [2] where some stations are also equipped with infrasound detectors as a part of the infrasound array of the Dutch meteorology institute KNMI.

cheers
- Bonzo -

[1] http://onlinelibrary.wiley.com/doi/10.10...0/abstract
[2] http://lofar.org/about-lofar/general-inf...troduction

[Tobi]

Hi Bonzo,

Infrasound could be interesting and I've already bought a microbarometer some while ago, but hadn't time for experiments.

Here is an article (German) with some circuit just as an example: http://www.elektroniknet.de/messen-teste...ikel/33/0/ I also have some more information about that in a printed magazine.

We currently can not support you much here, but if someone wants to do his own experiments, then I can help with firmware modifications to evaluate analogue/digital signals on the RED controller.

Best regards
Tobi

[RichoAnd]

Of course it is a proposal, and a good one
As recently as last weekend I designed the amplifier and filter
I have bought lots of microphones, both condenser and piezo
I made a simple setup to get an idea of sensitivity, etc.
The biggest challenge is the wind noise and the mechanical setup
We are in the process of System BLUE, but in the breaks I look at projects that can be related to our lightning monitoring, among them is infra-sound, light and magnetic field changes
System BLUE still has the highest priority, and when it is up and running that will be looked at further improvements and then infrasound
It has been around earlier and Tobi'll make the necessary additions to the initial tests

[cutty]

Of interest?
   

[Bonzo]

Thanks for your response. I'm pleased to see that infrasound is of
interest here and that some people have even done practical experiments.

Of course the development and implementation of the system "Blue" has priority.

As for the wind noise... The infrasound sensors which they placed at
the LOFAR sites utilize (porous?) hoses to average the pressure over a
larger area since the wavelength of a typical infrasound signal of
interest is much longer than that of wind, which is in the order of a
decimeter.

I'll try to find out more about the construction of these sensors.

I also read about the usage of subwoofer loudspeakers as a sensor.

I was considering the BMP180 microbarometric pressure sensor from
Bosch with 0.02 hPar Resolution. Advantage over microphones and
speakers would be that the BMP already delivers calibrated digital data.

Time to do some experiments myself...


Edit: You might find the following paper from Holleman et al interesting:
"VALIDATION OF AN OPERATIONAL LIGHTNING DETECTION SYSTEM"
http://www.vaisala.com/Vaisala%20Documen...system.pdf

[RichoAnd]

I have moved my answer to internal forum

http://www.blitzortung.org/Webpages/inde...=en&page=6

[Boumpower]

Hi
I will add my interrest for infrasound and magnetic field data processing.

Think that the powerfull knowledge of lightning location (distributed sensor array) applied on other kind of sensors can give interressant results :

- earth quake, explosion, meteorite impact location, solar eclipse...
- "front" wave real-time (or playback) display on map for a given event

Best regards
Olivier

[kevinmcc]

Hi
I will add my interrest for infrasound and magnetic field data processing.

Think that the powerfull knowledge of lightning location (distributed sensor array) applied on other kind of sensors can give interressant results :

- earth quake, explosion, meteorite impact location, solar eclipse...
- "front" wave real-time (or playback) display on map for a given event

Best regards
Olivier

Be interesting to have project like Blitzortung with meteors. Much more complicated as users would have to different tune to different existing frequencies to catch RF reflections. Works just like radar. Collaborating stations could map out entries.

http://www.livemeteors.com/

Infra sound is interesting idea, there MS5611 24 bit Barometric Pressure Sensor.
I may have to get one of these and see how sensitive the senors is to sound pressures and thunder during a storm.
Also wonder how useful barometric data would be for tracking storms and weather patterns, I do use the PressureNet app on my phone to send location and barometric data to Cumulonimbus .

[RichoAnd]

MS5611's sensitivity is too bad
1mBar = 100Pa

It looks like our immediate interest is in the range 1-10Hz (0,1-20Hz)
Pressure level about 1Pa (+/- 10 Pa ???)
If this is true, we need to make the sensor ourselves
Piezo or Electret mic

http://www.mouser.dk/ProductDetail/Sensi...lZeg%3d%3d

http://www.iris.edu/hq/instrumentation_m...alk-v2.pdf

http://l2a.ucsd.edu/local/Meetings/2000_.../07_08.pdf

http://pubs.usgs.gov/of/2014/1253/downlo...4-1253.pdf

http://onlinelibrary.wiley.com/doi/10.10...034193/pdf

[kevinmcc]

Thanks for the information.

I had looked at some of the other sensors on that were made for infra-sound.

[David.Gamble]

Hi
I will add my interrest for infrasound and magnetic field data processing.

Think that the powerfull knowledge of lightning location (distributed sensor array) applied on other kind of sensors can give interressant results :

- earth quake, explosion, meteorite impact location, solar eclipse...
- "front" wave real-time (or playback) display on map for a given event

Best regards
Olivier

Off topic but you maybe interested in http://fireballsinthesky.com.au/2016/01/...meteorite/. These guys have an array of "cheap" ($5000) all sky cameras which they use to work out trajectory and impact point. They recently recovered their first newly arrived meteorite.