Search results
Results from the WOW.Com Content Network
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa ), which is equivalent to 1,013.25 millibars , [ 1 ] 760 mm Hg , 29.9212 inches Hg , or 14.696 psi . [ 2 ]
The U.S. Standard Atmosphere is a set of models that define values for atmospheric temperature, density, pressure and other properties over a wide range of altitudes. The first model, based on an existing international standard, was published in 1958 by the U.S. Committee on Extension to the Standard Atmosphere, [ 9 ] and was updated in 1962 ...
Pressure as a function of the height above the sea level. There are two equations for computing pressure as a function of height. The first equation is applicable to the atmospheric layers in which the temperature is assumed to vary with altitude at a non null lapse rate of : = [,, ()] ′, The second equation is applicable to the atmospheric layers in which the temperature is assumed not to ...
This made the diagram useful for analysis techniques that were then being adopted by the United States Air Force. Such a diagram has pressure plotted on the vertical axis, with a logarithmic scale (thus the "log-P" part of the name), and the temperature plotted skewed, with isothermal lines at 45° to the plot (thus the "skew-T" part of the ...
Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. Thus air pressure varies with location and weather . If the entire mass of the atmosphere had a uniform density equal to sea-level density (about 1.2 kg/m 3 ) from sea level upwards, it would terminate abruptly at an altitude of 8.50 ...
The U.S. Standard Atmosphere is a static atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes or elevations. The model, based on an existing international standard, was first published in 1958 by the U.S. Committee on Extension to the Standard Atmosphere, and ...
An altimeter is intended to be used at different levels matching the corresponding atmospheric pressure to the altitude, while a barometer is kept at the same level and measures subtle pressure changes caused by weather and elements of weather. The average atmospheric pressure on the Earth's surface varies between 940 and 1040 hPa (mbar).
The standard atmosphere was originally defined as the pressure exerted by a 760 mm column of mercury at 0 °C (32 °F) and standard gravity (g n = 9.806 65 m/s 2). [2] It was used as a reference condition for physical and chemical properties, and the definition of the centigrade temperature scale set 100 °C as the boiling point of water at this pressure.