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  2. International Standard Atmosphere - Wikipedia

    en.wikipedia.org/wiki/International_Standard...

    The International Civil Aviation Organization (ICAO) published their "ICAO Standard Atmosphere" as Doc 7488-CD in 1993. It has the same model as the ISA, but extends the altitude coverage to 80 kilometers (262,500 feet). [7] The ICAO Standard Atmosphere, like the ISA, does not contain water vapor. Some of the values defined by ICAO are:

  3. Lapse rate - Wikipedia

    en.wikipedia.org/wiki/Lapse_rate

    As an average, the International Civil Aviation Organization (ICAO) defines an international standard atmosphere (ISA) with a temperature lapse rate of 6.50 °C/km [7] (3.56 °F or 1.98 °C/1,000 ft) from sea level to 11 km (36,090 ft or 6.8 mi).

  4. U.S. Standard Atmosphere - Wikipedia

    en.wikipedia.org/wiki/U.S._Standard_Atmosphere

    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 ...

  5. Surface weather observation - Wikipedia

    en.wikipedia.org/wiki/Surface_weather_observation

    ASOS sensors, located at Salinas, California. Surface weather observations have traditionally been taken at airports due to safety concerns during takeoffs and landings. The ICAO defines the International Standard Atmosphere (also known as ICAO Standard Atmosphere), which is the model of the standard variation of pressure, temperature, density, and viscosity with elevation/altitude in the ...

  6. Flight level - Wikipedia

    en.wikipedia.org/wiki/Flight_level

    In aviation, a flight level (FL) is an aircraft's altitude as determined by a pressure altimeter using the International Standard Atmosphere. It is expressed in hundreds of feet or metres. The altimeter setting used is the ISA sea level pressure of 1013 hPa or 29.92 inHg. The actual surface pressure will vary from this at different locations ...

  7. Reference atmospheric model - Wikipedia

    en.wikipedia.org/wiki/Reference_atmospheric_model

    The U.S. Standard Atmosphere model starts with many of the same assumptions as the isothermal-barotropic model, including ideal gas behavior, and constant molecular weight, but it differs by defining a more realistic temperature function, consisting of eight data points connected by straight lines; i.e. regions of constant temperature gradient.

  8. Meteorological instrumentation - Wikipedia

    en.wikipedia.org/wiki/Meteorological_instrumentation

    The ICAO defines the International Standard Atmosphere, which is the model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere, and is used to reduce a station pressure to sea level pressure.

  9. Pressure altitude - Wikipedia

    en.wikipedia.org/wiki/Pressure_altitude

    In aviation, pressure altitude is the height above a standard datum plane (SDP), which is a theoretical level where the weight of the atmosphere is 29.921 inches of mercury (1,013.2 mbar; 14.696 psi) as measured by a barometer. [2]