Hi everyone,
I would think that there's a high correlation between the polarity of the IMF
and the K/A indices, so this polarity may not tell us any more than the K/A
indices. There is a topbander on the other side of the Atlantic (darned if I
can remember who it is at the moment - as soon as I send this e-mail I'll
probably remember) who believes he sees a correlation between his 160-Meter
propagation and the speed and dynamic pressure (both are also on the dials at
the SWPC's "space weather now" link).
As for stratwarms, the winter anomaly has always been measured as a daytime
event. That's because the NO spills into the lower latitudes and is easily
ionized by solar radiation. But we do our DXing on 160 at night, so it's tough
to tie more absorption at night to stratwarms. In contradiction with W4ZV's
belief, long ago I took a look at IV3PRK's log to NA under stratwarm and
non-stratwarm conditions, and couldn't really come up with anything conclusive.
Another one of the mysteries of 160-Meters.
And D-region bite-outs also show up in rocket flight data and incoherent
scatter radar in the normal ionosphere - away from the higher latitudes where
PMSE occurs. I'm sure these bite-outs (a bite-out is a dramatic reduction in
D-region electron density over a very narrow altitude range) help reduce
absorption, but I suspect they are very fleeting due to the very dynamic nature
of the D-region.
Carl K9LA
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Topband Reflector
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