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    Re: Extremely poor conditions??
    From: Alexandre Eremenko
    Date: 2012 Mar 20, 09:31 -0400

    Thank you very much.
    1. Let me bring to your attention that it is the end of March today,
    and all messages in our archive for 2012 are still listed under January.
    2. The surface water temperature 3 days later was 40 F (I don't know where
    to find the temperature for March 17. We were observing from the part of
    the jetty which is adjacent to the shore. Bill walked to the end of the
    jetty, (it protrudes from the shore to the lake) and says it was chilly
    on the lake end.
    So you mean that the layer of cold air near the water surface acts
    like a sort of mirror, and the ray can be bent in the opposite direction
    to the usual one by as much as 7'.
    Most CelNav books do not warn about this.
    Is there a way for a navigator who does not know his exact
    position to figure out that such thing is happening?
    Well, I sort of remember some discussion of this on the "old list"
    under "Anomalous refraction", let me try to find it.
    We should have tried the artificial horizon which we had with us!
    On Tue, 20 Mar 2012, Frank Reed wrote:
    > Hello Alex, you wrote:
    > "Bill promises to find the water temperature of water on this day,
    > but it is really hard to believe in this kind of abnormal refraction. "
    > I think this is exactly what you were seeing. The lake water is still very 
    cold and then we had this sudden "heat wave". Seriously: 80 degrees 
    Fahrenheit on St. Patricks Day in Chicago?? There have been afternoon and 
    evening fog banks on the lake shore, dense and cold. The conditions that 
    produce this dense, cold, low-hanging fog are notorious for abnormal 
    refraction, too. I think you have seen a really fine example of this!
    > -FER
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