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> I am not sure that all members of the metopitics discussion forum are
> interested in our discussion.
I agree. Please do however note, that that is more a rule than an
exception
in newsgroup messages and the current conversation does involve a
major scientific problem. Three personal e-mails thank us all of the
conversations, one has made reservations towards it.
I appreciate your paper on elliptical halos
> in weather.
Thank you.
So, I wonder why you do not write a paper on the explanation
> of elliptical halos by pyramidal crystals.
We are waiting for a/ more polarisation observations, b/ that Tape´s
program is succesfully translated to PC language, that would make
it possible to explore such simple ice crystal structure possibilities
that are yet not covered by other programs. The latter is proceeded
by Moilanen at the moment.
I guess, the reason is that
> you do not trust your computersimulations.
Sure. The preliminary simulations are made by Kinnunen. By using
one population only they seem to match 3 elliptical halos
simultaneously. However it is yet approximate. As you say, we do
not trust it yet. We need Tape´s program in PC for several reasons
this being inappropriate and impractical place to discuss that in detail.
I am sorry, but I prefer to
> continue the discussion of the details after having analysed the photo
> of the colored elliptical halos by myself
Sure.
and after having read an English
> version of your article on elliptical halos in the Finish journal.
I dont understand what an earth article you are referring to? Where is no
recent article in our magazines that would even intend to cover this
current issue.
> But I like to clarify two points of the previous discussion:
> 1) In our paper we write that from a critical review of the 23 reports
> and from interviews of the Finish observers in June 1995 it is evident
> that most of the elliptical halos occured in the snowy virga of
> altocumulus clouds. Is this still correct ?
It seems to be an oversimplification of this matter. In many cases, sure,
there has
been Ac Virga in the sky, but especially in the large new load of 1996
photos
(that Riikonen could not have available in June 1995) Cirrocumulus or
virga of
that has been in charge.
> 2) I wrote in my last email that our model does not predict color
> separation of the rings because they are produced by multiple
reflections.
> Indeed, multiple reflections is the main rayclass. However, there are
small
> contributions from other rayclasses including refraction. Unfortunately
we
> did not check in the simulations the amount of these contributions. So,
the
> model is consistent with the observation of slightly colored rings.
To the present situation there is cause to say, that that model MIGHT be
consistent with slightly colored rings, whereas Piikki´s photographs show
such clear coloring that normally is evident in refraction origined halos.
> By the way, there are a few displays which directly show the effect of
> multiple scattering. I have a slide of the 18.2.88 display showing
> that the intensity of the ring varies along the ring. The intensity
decreases
> towards the horizon.
This is quite normal and could be due to several effects. It doesn´t
form a good proof by any standards when halos are involved. If one
watch multiple scattering simulations and compare them to the precise
forms of ellipses one must notice, that the two are not a precise match.
For instance display by Ruoskanen in 1993.
I wonder why you did not publish this
> interesting photopraph of the 18.2.88 display but another one that only
shows
> the upper part of the ring.
When we first published elliptical halo photographs, there was no modern
model with which we would have deliberately agreed or not agreed
with. A lot of pictures of 18.2.1988 were send to Weather and due to
printing difficulties they failed to publish any of them. Later Applied
Optics
and Marine Observer corrected for that.
The sole basis of favoring pictures by the editors of those papers as far
as
I am aware of was to choose the brightest example. There is no case to
suggest that we would deliberately omit evidence and this is easily
proved. All pictures of 18.2.1988 were carefully traced to drawings and
published as a graphics series: including the picture you mention. If you
open the Weather article again , you cannot fail to notice
that being a fact. Didn´t you remember that? Also the simple fact that
you have those pictures in your hand, that we actually have send them to
you (and simultaneously a lot of other people around the world)
hardly shows that we would want to hide them, or does it?
What goes to Visser´s outdated model, it has been cited in present and
previous convversations only as a historical curiosity
and an example of that general line of thought.
Regards, Marko
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