John Pethick
Hi all

Over the last few years the LPATS system and now GPATS , do at times
give isolated observations of what seem to be anomalous reports of
lightning, sometimes in areas that seem to be incorrect or unlikely
locations for thunderstorm activity.

I have taken a minor  interest over a few years in red sprite and blue
jets and details similar to those in the article below from Nature
magazine.
 

Electrical discharge from a thundercloud top to the lower ionosphere
V P PASKO, M A STANLEY, J D MATHEWS, U S INAN & T G WOOD
http://www.nature.com/nlink/v416/n6877/abs/416152a_fs.html

The question or idea that I am putting forward, is to ask whether it is
possible that some of the strangely positioned strikes may sometimes be
an tropospheric or ionospheric electrical discharge, probably lightning,
but perhaps sprites or jets?
If this is correct, then perhaps we can start to think that the rare
reports of lightning from clear skies, lightning from skies without
obvious deep convection may be possible.

The other query about the above article, is whether aircraft flying
above thunderstorms are in fact at risk of electrical discharge to the
ionosphere, and whether this risk is of the same danger potential as
normal lightning, or does it pose a bigger risk.  And do thunderstorms
in cold convection with low tops (ie, I have seen lightning from clouds
with tops at 14,000 ft off Sydney) also have some potential to produce
sprites or jets?

Any thoughts?

John Pethick
East Sale RAAF Base

Michael Foley
Hi,

That was a fascinating article.  John, this example was in association with
a thunderstorm.  Where would the static electricity come from to generate
discharges to the ionosphere, if not from a storm?  Maybe what people call
'clear air lightning' is them seeing such discharges from storms which are
a long way over the horizon.

Bye,

Michael.

Andrew Tupper
Michael,

I apologise for being predictable, but don't forget that lightning has been
very commonly observed with volcanic eruptions (with various explanations
given, including differential charging of the separating dust & gases), as
well as with nuclear explosions.  Maybe there are some processes in the
upper atmosphere which are unrelated to storms, but can result in lightning?

cheers Andrew