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> George H you wrote:
> "Dave makes a fair point,  but as I see it, it would apply only to
> observations where a significant  fraction of the length of the sight-path
> to the horizon is over the land (or  sandy shore, or drying reefs,
> whatever). Otherwise, the surface temperature,  even in shallow water, would
> not differ all that much from the open sea,  except in some very-odd
> environments."
>
> There's more to it than that.  You can get more complicated layering of air
> layers with different temperatures  close to shore. Near Mystic, Connecticut
> in
> the spring and fall, it's not that  uncommon to see five or more arcminutes
> of anomalous dip, and this is for sights  taken on water (but within sight of
> land).

This is something that has been bothering me since my experiences on Lake
Michigan last weekend.  With approx. 65F water temperature, 85F air
temperature, and a white strip apparently covering the sharp horizon, I
would have expected my Ho's to be larger than my Hc's as the line I used
between the water/white strip might have been lower than the actual horizon.
I was surprised to find all my shot Ho's to be smaller than Hc's.  I would
not discounting pilot error on my part of course.

As a rule of thumb, what is the trend of,  "...it's not that  uncommon to
see five or more arcminutes "of anomalous dip, and this is for sights  taken
on water (but within sight of land)."  That is, how will it shift Ho vs. Hc?
Is a trend semi-predictable trend for cold water/warm air and/or warm
water/cold air?

Thanks

Bill

   

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