Interpreting infrasound recorded on Boom during wind storms

RBOOM & Infrasound
#1

I recorded infrasound that seems to correlate well with times of strong winds measured on our Boom at the Blue Hill Weather Observatory in the Boston area. See attached, and here:

The correlation between strong winds and infrasound seems very clear, but I am not finding much published on the question of what the mechanism is that causes winds to generate infrasound. There is a lot on “microbaroms” generated in oceans, but I’m not finding much on what makes winds generate infrasound in land areas.

Do any of you in this Shake/Boom community have good information about what makes strong winds generate (or at least be associated with) infrasound in land areas? Any other ideas about these recordings are also welcome?

I did find this to be helpful, as a start:

Blue_Hill_Infrasound_Wind_121720
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Blue_Hill_Infrasound_Wind_093020
Blue_Hill_Infrasound_Wind_093020927×749 209 KB

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#2

I’ve noticed this too and always assumed that the Boom is sensing turbulence caused by the wind interacting with structures on the ground.
Gabriel Katul at Duke University has done a whole lot of work on the turbulence resulting from wind interacting with trees. This stuff quickly gets very complicated, but he explains it well. I hadn’t thought of applying some of his analysis techniques to data from the Boom, but it might be worth a go…

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#3

Thanks, TideMan.
It is very helpful to get a 2nd opinion on this :slight_smile:

I think what I was picturing as a first-guess, simple model is the same as what you describe here: The wind shakes the trees and structures, and the shaking trees and structures generate infrasound. Is that the simple idea (before going intto complications)?

The Boom is inside this building, at the top of the hill, either inside the window shown by the arrow (or the window above that - I will check on that).

Blue_Hills_Weather_Observatory_(6117762013)
Blue_Hills_Weather_Observatory_(6117762013)3648×2736 2.6 MB

I couldn’t find any of Gabriel Katul’s work on this topic. Let me know if you have links to something of his I could read on this.

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#4

This is another example, from a Boom that we are running in Antrim, NH.

Antrim_Wind_110318
Antrim_Wind_1103181219×1077 534 KB

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#5

Being able to “see” things on RB is all about minimizing the effects of wind noise. Unless of course what you are interested in is the wind itself. Most of the big infrasound monitoring installations have the air pressure inlets right at ground level - a few cm above ground at most and sometimes buried in porous media. I am considering modifying my setup to effectively lower the pickup point. But I live on a a small mountain ridge which unavoidably generates infrasound due to the interaction of wind with the local topography, so there may be little I can do about that other than wait for quiet days/nights…

Anyway - Google found this wonderful article for me:
https://l2a.ucsd.edu/pub/WalkerHedlin_NoiseReduction_Springer2010.pdf
In it you can find out about the physics of wind, the different types of wind noise and the interaction between wind and infrasound sensors. It’s quite good IMHO.

Ken.