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On Thu, 13 Sep 2007 19:45:44 -0700, "Matt Barrow"
wrote:


"Newps" wrote in message
...


wrote:

And several Mountain Flying books mention that specifically. The
official temperature anywhere is always in the shade. Ever seen a
runway
in the shade?


The runway will no doubt have a higher temperature and the air above
will be warmer than reported but how high would you need to fly to
reach the reported air temperature as measured in the shade?



An irrelevant question if you can't get there in the first place. But
if
you want an answer just look at the standard lapse rate as a start.

Remember, too, that a thermometer held in the sun is going to read higher
than a thermometer in the shade. What it's reading is the sunlight on
skin
or a thermometer, not the air temp. That's why they takes temps in the
shade -- the heat transfer is much different.


That is the reason for my question.

Surely standard lapse rate does not apply?

I'm wondering if the ground temperature will reduce quickly as you
climb. In other words will the air temperature drop quickly as you
leave ground effect or will it continue for many tens of feet?
I presume if there's any cross wind the hotter air above the runway
will drift sideways so maybe the effect will be less..

IIRC, there is a large difference within the first few feet, and the first
few tens of feet; but I don't recall what stardard there might be, nor the
effects of wind and ground clutter. Logically, everything would have some
influence...

Peter