Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site unccvax.UUCP
Path: utzoo!watmath!clyde!bonnie!akgua!mcnc!unccvax!dsi
From: dsi@unccvax.UUCP (Dataspan Inc)
Newsgroups: net.physics
Subject: Re: lightening bursts
Message-ID: <251@unccvax.UUCP>
Date: Sat, 27-Jul-85 10:56:33 EDT
Article-I.D.: unccvax.251
Posted: Sat Jul 27 10:56:33 1985
Date-Received: Wed, 31-Jul-85 04:58:31 EDT
References: <3305@decwrl.UUCP>
Organization: UNC-Charlotte
Lines: 37


   There was some gentleman on WBT (Charlotte, NC) last week talking with
Henry Bogan about some heavy duty research into why some areas are particularly
lightning prone.  I only got bits and pieces of it (running errands) but
they're doing some relatively sophisticated photography and statistical
analysis.  One thing the guest did mention was that they found lightning
paths were one 'helluva' lot longer than was originally postulated. Also,
with this ultrahighspeed photography and other techniques, it has been 
shown that the cloud-to-ground burst is definitely 'ground - to -cloud'
and that ionisation occurs first (several hundreds of milliseconds).
This thing (called a 'stepped leader') precedes the actual event in 
almost every case.

     They are also studying an area roughly between Orlando and Cape Kennedy
which seems to be exceptionally lightning prone (he said about 250,000 
discharges last year!)

     Apparently, lightning isn't the only kind of current that flows 
from the cloud - to - ground (or whatever).  I've noticed that when
a thunderstorm is threatening, even in the absence of lightning, larger
broadcasting towers (in excess of 350 feet) will put on some spectacular
feats of arcing and popping around the 'johnnyballs', strain relief 
insulators, and the base insulator.  The tower I've in mind rarely, if
ever, actually gets hit.  Is the tower actually reducing the potential
for strikes, or what?

     Finally, on a related subject: It seems that when I was in junior
high school, there was a big to-do about tornado producing thunderstorms
having either 1) an exceptional absorption or 2) radiation around 3.2
mHz.  There was a big plan to equip tornado-prone schools and other public
buildings with inexpensive receivers to monitor the effect. The articles
were in Popular Science, etc.

     Was this really true?

David Anthony
DataSpan, Inc