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Re: (meteorobs) Noctilucent Clouds
> Sirko, Thank you very much for the info and pointers to the noctilucent
> clouds. Are these the very-thready clouds that one often sees very high in
> the sky, or do they only appear from the viewpoint of earth observers when
> the sun illuminates them after sunset?
What you usually see high in the sky are cirrus clouds, which have nothing
to do with NLC. They belong to the uppermost cloud level and reach at
most altitudes of 12...15 km. NLC can only be seen in twillight, since
they are very thin and reflect only a little light, so that it has to be
quite dark for them to become prominent.
> Is there some other connection to meteors other than the common altitude?
> This is also the altitude of the lower E-layers; I wonder whether there is a
> connection between E-layer radio-reflectivity and the clouds?
There is a supposed connection between NLC and Polar Mesospheric Clouds,
which can be observed by radar (?) and satellites. Maybe there is also a
link to the E-layer, but I don't know much about that. I think, Alastair
McBeath of England has done some analysis in that direction.
Sirko
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