"Mike Rapoport" wrote in message link.net...
2C per thousand has nothing to do with stability. In unsaturated air,
2C/1000 is stable. In saturated air 2C/1000 is unstable. 2C/1000 is the
standard for calibrating altimeters, it has nothing to do with the real
atmosphere or stability.

Mike
MU-2

Adiabatic lapse rate is 1C/1"Hg for moist air (depending on moisture
content) and 3C/1"Hg for dry air. 2C/1"Hg is a representative average
for somewhat moist but unsaturated air. It is still a useful indicator
of stability. I would not discount is as a completely meaningless
number. It is a useful reference, just like 29.92" and 15C.

Please explain how 2C/1000 is used in altimeter calibration. I did not
know altimeters had any temperature corrections.