"Newps" wrote in message =
...
=20
John R. Copeland wrote:
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In the case of non-standard lapse rates, the lower the airport,
the more the altimeter differs from true height across mountain =
peaks.
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Lapse rate is temp and has little effect on the altimeter setting.=20
Because you are already separated from the ground by 2000 feet it is=20
much more important that everybody have the same setting. No such =
thing=20
as an area altimeter setting.


I think you could say lapse rate has *no* effect on altimeter setting.
QNH is whatever it takes to make the altimeter read right on the =
airport.
Lapse rate departure from standard, however, is the major contributor
to any difference between true height and altimeter reading aloft.
Humidity is a minor contributor by comparison.