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> DEBATE OF BOTTLINGER'S
>
> >From Les Cowley:
> >> I do not understand the appearance of Bottlinger's rings - would
> >> someone care to give a description?
>
> Your question hits directly to the biggest current debate on halos.
>
> These two phenomena seem very similar: 1. elliptical halos that
> appear surrounding the sun and moon themselves (see: Hakumaki and
> Pekkola, "Rare vertically elliptical halos", Weather (UK), December
> 1989). 2. Bottlinger's rings that appear around the subsun (or the
> "submoon"). Yet no-one knows for certain how these things are caused -
> this is mainly due to the total of lack of crystal samples.
>
> There is two competing explanations. The papers that Trankle refers
> (quoted below) are in favor of multiple scattering hypothesis, which was
> suggested first by Bottlinger himself in the beginning of this century.
> Sofar no halo has been convincingly shown to arise in multiple
> scattering. It is very much possible this will some day happen.
>
> Another choice is single scattering from such crystals that would have
> pyramidal surfaces suitable for building these small elliptical rings.
> One alternative representing choices of second hypothesis was discussed
> shortly by Visser in mid 20th century.
>
> The occasionally recorded color in elliptical halos, a recent
> polarisation observation by Sillanpaa and the observed brightnesses of
> elliptical halos and Bottlinger rings tend to favor single scattering.
>
> Regards, Marko
>
>
I - Eberhard Traenkle - like to explain shortly our explanation of
Bottlinger's rings and elliptical halos and make a comment to the
explanation by pyramidal crystals:
For the explanation of Bottlinger's rings we do not need multiple
scattering.
Bottlinger's rings are produced by single reflection at the top surface
of gyrating snow-stars. A stable fallmode of gyrating snow-stars was
observed,
performing flight experiments with styrofoam models in a staircase with a
free fall height of 15 m.
In our model Bottlinger's rings and elliptical halos are produced by the
same crystals at the same time. Elliptical halos are produced by multiple
reflections at gyrating snow-stars. Because it is a reflection phenomenon
the rings should not show color separation.
I am sorry, I cannot discuss the explanation of elliptical halos by
pyramidal crystals in detail. The idea of Visser is not plausible.
To my knowledge, there is only a short article in a Finish journal -
in Finish.
However, I think that the scattering by pyramidal crystals cannot explain
- that elliptical halos have mainly been observed in altocumulus virga
- that the rings have small widths and no fixed values of the radii
Best regards, Eberhard Traenkle
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