Re: thunder length?


Greg Campbell wrote:
halex2000 wrote:

Thank you all. Yes, I didn't belive really that it was a thunder, but this
low noise lasting 15/20 min was a lot strange for me. Luckily we never had
twisters (our landscape don't allow them) so I didn't think to them either.

I was thinking it might have been a downburst, distant hail, or even
something twisty.

Where do you live?

(Unless you have Mt. Everest in your backyard, the local landscape won't
have a big impact on severe thunderstorms or 'naders.)

Could it have been fed from an above cloud event? Apparently this
recently accepted phenomena is a super bolt that is most common or at
least has been observed most often over large plains such as the US mid
west.

There are a variety of bolts and shapes of them variously called elves
and sprites (until some as yet to be formed, select panel of pseudo
experts can come up with "better" nomenclature) that seem to derive
their power from the upper atmosphere and funnel into very large
thunder cells.

It has been suggested that strikes from these (or lightning generated
below them) can destroy airliners. That makes them not only very
powerful but indicates a strike sustained over an unusually long
period. (Still only fractions of a second but ten to an hundred times
longer than below cloud lightning.)

UK's Channel Five did a programme on it a few years back. As it's all
US research, there may be an occasional showing on one of the science
channels over there. Here's a very limited cover of what it is:
http://news.bbc.co.uk/2/hi/science/nature/3917137.stm

There is a little online about it but as the research only dates back
10 years or so max., it is still frontier stuff:
"Although there are documented examples of negative polarity CGs
causing elves, they are much less frequent, even though negative
polarity lightning is much more common than positive polarity
lightning. The reason may lie in the time-waveform of the -CGs being
relatively weak in the required frequency range. This continues as an
unresolved issue."
http://216.239.59.104/search?q=cache:stOt_ZPAZuAJ:www.fma-research.com/Sprites99/CHAPTER-IV.pdf+channel+five+mega+lightning+elves+sprites&hl=en&gl=uk&ct=clnk&cd=1
http://www.fma-research.com/Sprites99/CHAPTER-IV.pdf

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