Aercus Instruments™
- WeatherSpy
25 |
P a g e
4.3.3
Relative vs. Absolute Pressure
While in normal mode, Press and hold the
BARO./-
button for 2 seconds you can switch between absolute
(ABS) pressure and relative (REL) pressure.
The display console displays two different pressures:
absolute (as measured) and relative (corrected to sea-
level).
To compare pressure conditions from one location to
another, meteorologists correct pressure to sea-level
conditions. Because the air pressure decreases as you
rise in altitude, the sea-level corrected pressure (the
pressure your location would be at if located at sea-
level) is generally higher than your measured pressure.
Thus, your absolute pressure may read 969hPa at an
altitude of 305m, but the relative pressure could be
1016hPa.
Standard sea-level pressure is 1013hPa/29.92inHg. This
is the average sea-level pressure around the world.
Relative pressure measurements greater than 1013hPa
are considered high pressure and relative pressure
measurements less than 1013hPa are considered low
pressure.
