Next message: Bill: "Re: Anomalous dip. was: [NAV-L] Testing pocket sextant."
I've just posted a meassage, in the hope of reducing
misunderstandings, in which was the paragraph-
| When you observe a highway surface on a hot day, you can see a
bright
| "pool" on the surface, which is an image of reflected sky. But this
is
| NOT reversed dip, it's locally ENHANCED dip, in the normal direction
| of dip. It implies that even looking somewhat downward, into the
| highway ahead, you are still seeing the sky, and you have to look
more
| downward still until you see a view of the ground, at an enhanced
| angle of dip. That's because the temperature gradient over the
tarmac
| is hotter below, warmer above (the opposite way round to what we are
| hypothesising occurs over a sea surface). There is no inconsistency.
The hope of achieving clarity was in vain, when I write such
confusions as "the temperature gradient over the tarmac is hotter
below, warmer above". What I should have written, of course, was- "the
temperature gradient over the tarmac is hotter below, cooler above".
Now, I hope that's a bit clearer.
George
contact George Huxtable at
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
