[Aavso-sid-list] SIDs at 2009-11-27

[Peter Wilhelm Schnoor]

Hi Dave,

I just checked my second VLF-receiver, 12km away, and found those SIDs to
be confirmed.

You wrote:
> 
> Your SIDs must not have come from the sun since it was very quiet on the
> 27th.

Yes; sun was well below horizon here in Europe.

> What could have caused them?

Direct heating from below of the lower ionosphere by lightnings I suppose.
There was some thunderstorm activity over the North Sea but not impressive.

The onsets of the sids shown followed immediately after strong pulsative
interferences. So I'm thinking they have been caused by lightnings nearby.
But I never observed such strong effects...

Peter