Atmospheric pressure
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Atmospheric pressure, also known as air pressure or barometric pressure, is the pressure within the atmosphere of Earth. The standard atmosphere is a unit of pressure defined as 101.325 kPa, which is
Kollsman-type barometric aircraft altimeter
Cloud formation above Snæfellsjökull (Iceland), formed above the mountain by orographic lift
Hurricane Wilma on 19 October 2005. The pressure in the eye of the storm was 882 hPa (12.79 psi) at the time the image was taken.
Boiling water
Inch of mercury
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Inch of mercury is a non-SI unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States.
Early American barometer calibrated in inches of mercury
