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Geopotential height or geopotential altitude is a vertical coordinate referenced to Earth's mean sea level (assumed zero geopotential) that represents the work involved in lifting one unit of mass over one unit of length through a hypothetical space in which the acceleration of gravity is assumed constant. [1]
T = mean atmospheric temperature in kelvins = 250 K [4] for Earth m = mean mass of a molecule M = mean molar mass of atmospheric particles = 0.029 kg/mol for Earth g = acceleration due to gravity at the current location. The pressure (force per unit area) at a given altitude is a result of the weight of the overlying atmosphere.
Geopotential is the potential of the Earth's gravity field.For convenience it is often defined as the negative of the potential energy per unit mass, so that the gravity vector is obtained as the gradient of the geopotential, without the negation.
The gravity g′ at depth d is given by g′ = g(1 − d/R) where g is acceleration due to gravity on the surface of the Earth, d is depth and R is the radius of the Earth. If the density decreased linearly with increasing radius from a density ρ 0 at the center to ρ 1 at the surface, then ρ ( r ) = ρ 0 − ( ρ 0 − ρ 1 ) r / R , and the ...
In aviation, the term elevation or aerodrome elevation is defined by the ICAO as the highest point of the landing area. It is often measured in feet and can be found in approach charts of the aerodrome. It is not to be confused with terms such as the altitude or height. [1] Part of a topographic map of Haleakala , showing elevation.
Aviation altitude is measured using either mean sea level (MSL) or local ground level (above ground level, or AGL) as the reference datum. Pressure altitude divided by 100 feet (30 m) is the flight level , and is used above the transition altitude (18,000 feet (5,500 m) in the US, but may be as low as 3,000 feet (910 m) in other jurisdictions).
The elevation of the land surface varies from a low point of −418 m (−1,371 ft) at the Dead Sea, to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest. The mean height of land above sea level is about 797 m (2,615 ft). [108] Land can be covered by surface water, snow, ice, artificial structures or vegetation.
Elevation is defined as the vertical distance between an object and sea level, while altitude is defined as the vertical distance from an object to Earth's surface. [38] The elevation of Earth's land surface varies from the low point of −418 m (−1,371 ft) at the Dead Sea, to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount ...