What Is The Difference Between Absolute And Relative Pressure?
Absolute pressure is the measured atmospheric pressure.
Absolute pressure is not corrected to sea-level conditions.
To compare pressure conditions from one location to another, meteorologists correct pressure to sea-level conditions (referred to as relative pressure, or pressure relative to sea-level).
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 higher than your measured pressure if you live above sea-level and lower than your measured pressure if you live below sea-level.
The following is the absolute pressure lapse rate as a function of altitude for standard day conditions:
Relative pressure is the atmospheric pressure corrected to sea-level conditions.
To compare pressure conditions from one location to another, meteorologists correct the measured pressure (referred to as absolute 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 higher than your measured pressure if you live above sea-level and lower than your measured pressure if you live below sea-level.
Relative pressure is larger than absolute pressure unless you live at or below sea-level.
You can check your local airport's pressure.