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Location: UFOUpDatesList.Com > 2007 > Aug > Aug 11

Re: Hole In The Clouds

From: Michael Tarbell <mtarbell.nul>
Date: Fri, 10 Aug 2007 08:02:45 -0600
Archived: Sat, 11 Aug 2007 10:30:30 -0400
Subject: Re: Hole In The Clouds


>From: Michael Tarbell <mtarbell.nul>
>To: ufoupdates.nul
>Date: Thu, 09 Aug 2007 10:03:17 -0600
>Subject: Re: Hole In The Clouds

><snip>

>I am sorry to say I have only glimpsed thus far at the NARCAP
>report. I will be very interested to see what is included
>regarding the cloud layer thickness and the associated
>uncertainties.


Having now examined the report in somewhat more detail (at least
the cloud hole discussion), I will make bold (second post in a
row) to cite myself from the discussion here in January:

http://www.virtuallystrange.net/ufo/updates/2007/jan/m05-011.shtml

in which an expression is presented that places a limiting
perimeter on the position of witnesses that can actually see
clear sky through the cloud layer. Specifically, the limiting
ground range R for such a witness, from a point on the ground
directly beneath the hole, is given by:

R = D(0.5 + H/T)

where D is the diameter of the hole, H is the height of the base
of the cloud layer, and T is the thickness of the layer.

The NARCAP report indicates that there were two distinct cloud
layers, one with a base height of 1900 ft and a thickness of
1800 ft, and the other with a base height of 8000 ft and a
thickness of 1000 ft.

Based on witness estimates for the size of the object and the
hole size relative to it, let us adopt a fairly generous value
for D of 70 ft. Even considering only the lower cloud layer, the
expression above yields R ~ 109 ft. That is to say, everyone (if
anyone) who saw clear sky through the hole must have been within
a circle of diameter 218 ft, directly below the hole.

The situation becomes even more severe if we include the upper
cloud layer, which effectively increases the thickness of the
barrier to 7100 ft (base of lower cloud layer to top of upper
cloud layer). Under these circumstances, we get R ~ 54 ft, i.e.,
all such witnesses within a circle of diameter 108 ft.

One begins to question whether _anyone_ actually saw clear sky.
One possibility is that the lower cloud layer was predominantly
illuminated on its _underside_, such that the witnesses mistook
the darker, shaded walls of the hole 'tube' as being clear sky.
This is not altogether implausible, as the sun was very near the
horizon at the time of the sighting.

My apologies if the above is already discussed somewhere in the
report, if so it escaped me.

Mike



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