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    Re: Dip uncertainty
    From: Alexandre Eremenko
    Date: 2004 Dec 8, 10:56 -0500

    Deare Trevor:
    
    On Tue, 7 Dec 2004, Trevor J. Kenchington wrote:
    
    > The problem with an experimental approach would be that we are dealing
    > with a stochastic system.
    > It
    > would need a huge amount of data to produce global statistics on the
    > phenomenon.
    
    Agree.
    
    > Then there is the problem of how to measure the amount of anomalous
    > refraction (with a dipmeter?).
    
    Why not?
    
    > Or would you rather measure the
    > temperature gradient and calculate the refractive index?
    
    If the refraction can be reliably calculated from the temperature
    gradient (you probably mean temperature profile? temperature as
    a function of height?) then no massive statistics is necessary,
    and the answer can be found theoretically (and then tested).
    Surely there is an enormous statistics of temperature profiles
    everywhere and at every time.
    
    > Finally: Maybe somebody has studied this but who would have sponsored
    > research relating to the heights of eye typical on small boats?
    
    Well, just do not mention "small boats" in your research application:-)
    State the question as: on an aircraft carrier, what is better, to do
    observations from the top of the tower or from a low deck? And also
    mention torpedo boats, or better,
    submarines taking sights through their periscope:-)
    
    In general, a lot of research is done without any immediate profit,
    or any immediate practical goal.
    (For example, I am doing this sort of research all my life, and
    I am reasonably sponsored:-)
    
    > But if the issue really is the first few feet of the
    > atmosphere versus the next layer above, there may not be much of a
    > gradient in frequency and severity of anomalies between deck and
    > masthead and hence nothing to study.
    
    Nevertheless, I conjecture that this sort of research has been
    done sometimes, maybe by those Pulkovo people mentioned by Shufeldt.
    The problem is essentially how to find this literature.
    
    > Scholar.google shows only 158 journal citations for "anomalous dip"
    
    I tried these exercises. Google only finds what's available on the
    web. (And even this it does poorly). And most of the research papers until
    1990-s are NOT on the web,
    and I afraid, will never be.
    
    Alex.
    
    P.S. I do not know much about atmospheric science, but do very short
    radiowaves (the sort used in radio-location) also experience refraction?
    Another hint for the literature research: the question could be very
    relevant to artillery.
    
    
    

       
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