Next message: Marcel Tschudin: "Re: Anomalous dip. was: [NAV-L] Testing pocket sextant."
Dear Marcel and George,
> I guess you ment -0.0065 ?
>
> Alex wrote:
> "The water was very cool (and always is) here. I mean most people do not
> dare to swim in Kiel till the beginning of August:-) But the air was hot, at
> least that was what I felt:-)"
>
> Isn't that just the type of condition to create a high temperature gradient?
There is some confusion here. Under the conditions I described,
the gradient will be high indeed, but in what direction?
The air is cooler nearer the surface. That is the temperature
INCREASES with height. If I understood George's message
correctly, "inversion" that can lead to positive dip
occurs when we have the opposite phenomenon: the temperature
DECREASES with height.
See his example with the desert where the surface is hot and
the air is cool. In the case of Kielerforde we are discussing
the water was cool and the air hot.
So I would expect refraction in the usual direction,
maybe stronger than usual. But the dip will be negative.
Alex.
