Tuesday, September 23, 2008

Hail Cannons Making a Comeback!

You gotta love it when "real" science and doing something about the weather collide.

Is this technology NOAA approved??

HLG

http://edition.cnn.com/2008/US/09/22/hail.cannon.ap/index.html

1 comment:

The Weathergeeks said...

To disrupt hail formation particles, a certain amount of energy would be required at the atmospheric level where hail is formed (~6000 m). Hail Cannon specifications can be found at http://www.spag-web.com/docs/SPAG-Hailcannon_specification_sheet.pdf

Sound from the hail cannon would spread due to two effects (three depending on the type of surface the hail cannon rests upon). The first type of spreading is geometric spreading - which is independent of the sound frequency - and would spread with a loss of x dB per distance squared.

The specifications state that the hail cannon creates 100db/100 meters of sound - therefore, after 1000 meters, the sound energy created by the hail cannon would be reduced by almost 3/4ths - and would be around 30db.

I'd have to find out how much energy would be required to disrupt hail formation - but I would guess that it would be around 70 or 80 db. Since hail is generated about 6000 m in the atmosphere - and since sound energy also spreads due to a second influence (atmospheric effects which are quite large in thunderstorms) - then I would say that the hail cannon would not have much impact on hail generation.

But I'm not an expert.
BB
(I get confused, is this the science forum website or is it sciencegal's?)