The U. S. Standard Atmosphere is a series of models that define values for atmospheric temperature, density, pressure and other properties over a wide range of altitudes. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Altitude is the Elevation of a point or object from a known level or datum (plural data The first model, based on an existing international standard, was published in 1958 by the U. S. Committee on Extension to the Standard Atmosphere, and was updated in 1962, 1966, and 1976.

1962 version

The basic assumptions made for the 1962 version were:^[1]

• air is a clean, dry, perfect gas mixture (cp/cv = 1. Gas while Ideal gas and this article are constructed -->By definition a perfect gas is one in which intermolecular forces are neglected Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 40)
• molecular weight to 90 km of 28. The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one 9644 (C-12 scale)
• principal sea-level constituents are assumed to be:
  • N₂–78. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 084%
  • O₂–20. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the 9476%
  • Ar–0. This article pertains to the chemical element For other uses see Argon (disambiguation. 934%
  • CO₂–0. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single 0314%
  • Ne–0. Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 001818%
  • He–0. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical 000524%
  • CH₄–0. Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. 000 2%.

• assigned mean conditions at sea level are as follows :
  • P = 0. Mean sea level (MSL is the average (mean height of the Sea, with reference to a suitable reference surface Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface 1013250 MN/m2 = 2116. 22 psf = 14. 696 psi
  • T = 288. The pound per square inch or more accurately pound-force per square inch (symbol psi or lbf/in² or lbf/in²) is a unit of Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature 15 K = 15 °C = 59 °F
  • ρ = 1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 225 0 kg/m3 = 0. 076474 lb/ft3
  • g = 9. Earth's gravity, denoted by g, refers to the Gravitational attraction that the Earth exerts on objects on or near its surface 80655 m/s2 = 32. 174 1 ft/s2
  • R = 8. Relationship with the Boltzmann constant The Boltzmann constant kB (often abbreviated k) may be used in place of the gas constant by working 31432 J/mol-K = 1545. 31 ft lb/lb-mol-deg R.

See also

• Atmospheric models
• NRLMSISE-00
• International Standard Atmosphere

References

• U. Static atmospheric models describe how the Ideal gas properties (namely pressure temperature density and molecular weight of an atmosphere change primarily as a function of NRLMSISE-00 is an Empirical, global model of the Earth's atmosphere from ground to space The International Standard Atmosphere (ISA is an atmospheric model of how the Pressure, Temperature, Density, and Viscosity S. Extension to the ICAO Standard Atmosphere, U. S. Government Printing Office, Washington, D. C. , 1958.
• U. S. Standard Atmosphere, 1962, U. S. Government Printing Office, Washington, D. C. , 1962.
• U. S. Standard Atmosphere Supplements, 1966, U. S. Government Printing Office, Washington, D. C. , 1966.
• U.S. Standard Atmosphere, 1976, U. S. Government Printing Office, Washington, D. C. , 1976 (Linked file is 17 MiB).

1. ^ Tuve, George Lewis; Bolz, Ray E. (1973). CRC handbook of tables for applied engineering science. Boca Raton: CRC Press. ISBN 0-8493-0252-8.  

External links

• NASA GSFC ModelWeb
• A mathematical model of the 1976 U.S. Standard Atmosphere
• Online 1976 US Standard Atmosphere calculator and table generator
• NewByte standard atmosphere calculator and speed converter