STATION PRESSURE VS ALTIMETER

UNLIKE OTHER AWOS SYSTEMS
THE FAA APPROVED ALTIMETER PROCEDURE FOR SUPER AWOS
IS TO TAKE ANOTHER APPROVED ALTIMETER SOURCE NEARBY
(ALTIMETER CAN ALSO BE EXPRESSED AS SEAL LEVEL PRESSURE)
AND TRANSFER (SET) THAT KNOWN-GOOD VALUE INTO THE SUPERAWOS
IT IS SLIGHTLY DIFFERENT FROM OTHER SYSTEMS
BUT IT IS ACTUALLY MUCH SIMPLER!

In the example below, assume you are in Denver at ~5,000 feet above sea level, at "A"

Next, drill a well down 5,000ft to sea level below to "B"

While STATION (RAW) PRESSURE would vary depending on where you measured the pressure,

Varying by about 1" InHg per 1,000 ft vertically

The ALTIMETER value, i.e. the station pressure adjusted for your height above sea level,

Remains the same at all altitudes.

The "STANDARD ATMOSPHERE" correction table is merely a mathematical average

which never occurs in nature.

IN REALITY, the relationship between temperature, dewpoint and pressure with altitude are not fixed!