[Laser] Fwd: optical ducting

[Kerry Banke]

I received this note on observations of optical ducting that I thought 
might be of interest to the group.  Any comments?
  - Kerry N6IZW -


>From: Frank Kelly <fk@event1.com>
>To: "'kbanke@qualcomm.com'" <kbanke@qualcomm.com>
>Subject: optical ducting
>Date: Fri, 7 Feb 2003 17:44:31 -0800
>X-Mailer: Internet Mail Service (5.5.2653.19)
>
>Kerry,
>I sent the message immediately below to my friend W1LP.  He and I have been
>working some long paths on 10GHz over water from his tanker ship.  In his
>reply, Clint mentioned laser DX and I thought of you.  Do you know about
>this????
>Frank
>
>
>
>
>Hi Clint,
>
>I saw an "optical duct" for the first time the other day and wanted to
>ask you if you've seen this before on your journeys.
>
>Inversion layers here off the California coast are normally associated
>with the hot, dry, high pressure weather during summer.  Last week
>Southern California had a Winter weather anomaly with one day of 90
>degree temps and the lowest inversion layer I've ever seen over the
>ocean--about 500 feet. The air was hot and absolutely dead.
>
>I was traveling right along the coast on a stretch of the road that was
>maybe 200 feet elevation when I noticed the inversion layer was
>reflecting the image of a container ship maybe 10 miles out on the
>horizion.  The ship was well over my horizon as I could only see the top
>half of it, but about 500' above the ship in the inveersion layer was a
>fuzzy dark image of the ship's outline in the sky, moving across the sky
>with the ship below it!
>
>At the same time, the Santa Barbara Channel Islands out in the same area
>across the channel, and whose highest elevations were above the
>inversion layer, were also effected.  The inversion reflected/refracted
>the visible part of the islands below the layer, drawing a thick dark
>line across the sky matching the width of the islands.
>
>There is no question as to what I was seeing.  Have you see this to???
>
>Frank WB6CWN
>
>
>
>
>
>Frank,
>
>I have seen it many times on the water, and in quite a few different
>forms, stuff like lighthouses observed visually from 100 miles away when
>they can only be seen from 20 miles with the distance to the
>horizon.....
>
>I sure it would be a great way to set a laser DX record....
>
>An even foot of snow here today, I sure miss those days in the tropics.
>I spent the day on a ship in zero visibility in a blizzard....
>
>73, Clint