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Thank you Eberhard of your interesting answer. I suggest we
proceed since disagreement in meteorological optics is quite
rare and therefore particularly interesting. Naturally I d
like to point out such things that might weaken your theory
or be in support of another choice.
I invite you to do the same to any arguments by me.
The main thing is finding the right solution - regardless
who does it or who might have been wrong or right in the past.
- NUMBER OF TILT POPULATIONS?
>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.
I'll skip the obvious part of the difference between tiny ice crystals
in air and large styrofoam models in staircase, since it doesnt bring
much new. Instead: What kind of tilt angles do you need to those snow
stars in order to get say 3-4 different sized ellipses simultaneously in
the sky? How many different tilt populations do you need?
2. SAME CRYSTALS AS WELL
>In our model Bottlinger's rings and elliptical halos are produced by
>the same crystals at the same time.
This can be reached by single scattering in pyramidal crystals as
well. Simulations by Timo Kinnunen reach exactly the same.
3. THE QUESTION OF COLOR
>Elliptical halos are produced by multiple
>reflections at gyrating snow-stars. Because it is a reflection
>phenomenon the rings should not show color separation.
Here you seem to put the theory dictating that observations and
photographs are wrong.
In recent photographic series of elliptical halos by Sillanpaa spectral
colors are quite clear. Colors were faintly evident for example in
Ruoskanen's 1993 display already. Hence: Supporting explanations based
in reflection only means consciensly omitting the color observations in
elliptical halos.
4. RESERVATIONS TO CLOUD TYPE AND NON-FIXED ANGLES
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
Elliptical halos are often observed in cirrocumulus lenticularis, altocumulus
lenticularis, in diamond dust against stratocumulus and possibly
in the virga of all or some of the mentioned cloud types. They have also
been observed in diamond dust from industrial smoke, in "blue sky"
nearby high cirrostratus etc. In many observations where the observer
has spoken of "altocumulus lenticularis" the cloud cells reveal in
photographs to be smaller than 1 degree, which is contradictive with the
definition and hence places the cloud to cirrocumulus types which are
far higher up.
It is not certain that the rings would not have fixed values of radii.
Equally it is difficult to explain by gyrations how at some day one
would have such and such many populations of snow stars permanently
tilted in one manner, and the next day permanently tilted in another
tilt angles. It is a really complex demand of behaviour. On the other
hand in the halo theory advanced so far hardly anything is complex.
>From the last sentence acknowledgement goes to Walt Tape.
Regards, Marko
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