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The lapse rate is the rate at which an atmospheric variable, ... (2 to 5 °F/1000 ft), as obtained from the International Civil Aviation Organization (ICAO).
a lapse rate given per kilometer of geopotential altitude (A positive lapse rate (λ > 0) means temperature increases with height) In the above table, geopotential altitude is calculated from a mathematical model that adjusts the altitude to include the variation of gravity with height, while geometric altitude is the standard direct vertical ...
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 ...
QFF is derived from the barometric pressure at the station location by calculating the weight of an imaginary air column, extending from the location to sea level, assuming the temperature and relative humidity at the location are the long term monthly mean, the temperature lapse rate is according to ISA and the relative humidity lapse rate is ...
Whether or not the atmosphere has stability depends partially on the moisture content. In a very dry troposphere, a temperature decrease with height less than 9.8 °C (17.6 °F) per kilometer ascent indicates stability, while greater changes indicate instability. This lapse rate is known as the dry adiabatic lapse rate. [3]
The adiabatic lapse rate is the rate at which the temperature of a rising or falling air mass lowers or increases per distance of vertical displacement. The ambient or environmental lapse rate is the temperature change in the (non-displaced) air per vertical distance.
As an average, the International Civil Aviation Organization (ICAO) defines an international standard atmosphere (ISA) with a temperature lapse rate of 6.49 °C per kilometer (3.56 °F per 1,000 feet). [14] The actual lapse rate can vary by altitude and by location.
The environmental lapse rate (/), at which temperature decreases with altitude, usually is unequal to the adiabatic lapse rate (/). If the upper air is warmer than predicted by the adiabatic lapse rate ( d S / d z > 0 {\displaystyle dS/dz>0} ), then a rising and expanding parcel of air will arrive at the new altitude at a lower temperature than ...