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LF: re re T/A tests and Solar events

To: "LF-Group" <[email protected]>
Subject: LF: re re T/A tests and Solar events
From: "Alan Melia" <[email protected]>
Date: Mon, 14 May 2001 20:06:30 +0100
Reply-to: [email protected]
Sender: <[email protected]>
Hi Laurie, All the parameters of the solar distubances are at least weakly
related so you will get some correlation with Sun-spot number of any other
parameter. When the sun spot number is high there is a higher likelyhood of
geomagnetic disturbances. When the sunspot number is low there is less
likely to be Flares and the associtaed CMEs, although I believe there may
still be Coronal hole events.

What you may like to try is a correlation to failure (i.e. a negative
correlation in statistical terms) with the Kp index, but delay it by one
day. My rationale behind that it that when the Kp is high (5 or above) there
are energetic ions injected into the atmosphere at the magnetic poles. These
create the Aurora but also drift down into the lower layers and spread out
into the D-layer (I believe). This latter effect seems to take about
24hours. The Index drops rapidly but the injected ions in the ionosphere
decay only slowly and the events can last for anything from 3 to 14 days.
The best archive I have of Kp is that published every month on the dxlc web
site. If you have the NOAA  SEC data the graphs and timings of the increases
are given in 3 hourly avaerages. The thing is that the increase in Kp
indicates that the plasma 'glob' of a CME or coronal hole event has made
impact on the ionosphere, with the possibility of injecting energetic
charges into the layer. The problem is that there is so much going on at
present and so many events running in to each other that it is difficult to
sort out cause and effect.

I would be interested in the dates you have as I have collected 75 graphs of
SXV now and I am having trouble relating them to propagation conditions. The
dates you were active and the dates you were heard (times if possible) would
be interesting.

I am getting some ideas on how to model these events and maybe draw some
conclusions, but it is probably quite contentious. (Watch this space)

If anyone would like the SXV graph archive please ask. I have not lodged
these with Rik as I did not know how to explain the relevance of the plots
on the propagation over the North Atlantic.

The SXV plots do show that the effects we have seen over the N.Atlantic are
also in action on shorter paths.

Cheers de Alan G3NYK
[email protected]

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