Sea level pressure; a term used in the United Kingdom by ATC and pilots.
Altitude above mean sea level based on local station pressure.
Altimeter setting (outside USA), relative to Man Sea level
altimeter setting to indicate height amsl.
acronym for standard pressure (1013.2 hectopascals) measured at mean sea level at one atmosphere. Used as an altimeter setting. Area QNH refers to a reference pressure setting applicable for all aviation activities in a particular area.
Altimeter sub-scale, giving elevation if the aircraft was on the ground at that precise point.
The current barometric pressure setting adjusted for the height of that airfield above sea level. In other words, an altimeter set to the QNH figure for that airfield would indicate the actual height of the airfield above sea level when the aircraft was on the runway. It would appear that the meaning of the N in QNH has been lost throughout the ages. [Q N Height
Altimeter setting to obtain aerodrome elevation when on the ground
QNH is a Q code. It is a pressure setting used by pilots, air traffic control (ATC) and low frequency weather beacons to refer to the barometric altimeter setting which will cause the altimeter to read altitude above mean sea level within a certain defined region. This region may be fairly widespread, or apply only to the airfield for which the QNH was given.