Sea level
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Mean sea level is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datum – a sta
This marker indicating sea level is situated between Jerusalem and the Dead Sea.
Sea level sign seen on cliff (circled in red) at Badwater Basin, Death Valley National Park
The Last Glacial Period caused a much lower global sea level.
Warming temperatures and melting glaciers are currently raising the sea level.
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
Sea level
…geodetic datum – that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead…
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