U.S. Standard Atmosphere
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. 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:[2]
- air is a clean, dry, perfect gas mixture (cp/cv = 1.40)
- molecular weight to 90 km of 28.9644 (C-12 scale)
- principal sea-level constituents are assumed to be:
- N2–78.084%
- O2–20.9476%
- Ar–0.934%
- CO2–0.0314%
- Ne–0.001818%
- He–0.000524%
- CH4–0.0002%.
- assigned mean conditions at sea level are as follows :
- P = 101325 Pa = 0.1013250 MN/m2 = 2116.22 psf = 14.696 psi
- T = 288.15 K = 15 °C = 59 °F
- ρ = 1.225 0 kg/m3 = 0.0764734 lbm/ft3
- g = 9.80665 m/s2 = 32.174 1 ft/s2
- R = 8.31432 J/mol-K = 1545.31 ft lb/lbmol-°R.
1976 version
This is the most recent version and differs from previous versions only above 32 km:
| Subscript b |
Height above Sea Level |
Static pressure |
Standard temperature
(K) |
Temperature Lapse Rate |
| (m) |
(ft) |
(pascals) |
(inHg) |
(K/m) |
(K/ft) |
| 0 |
0 |
0 |
101325 |
29.92126 |
288.15 |
-0.0065 |
-0.0019812 |
| 1 |
11,000 |
36,089 |
22632.1 |
6.683245 |
216.65 |
0.0 |
0.0 |
| 2 |
20,000 |
65,617 |
5474.89 |
1.616734 |
216.65 |
0.001 |
0.0003048 |
| 3 |
32,000 |
104,987 |
868.019 |
0.2563258 |
228.65 |
0.0028 |
0.00085344 |
| 4 |
47,000 |
154,199 |
110.906 |
0.0327506 |
270.65 |
0.0 |
0.0 |
| 5 |
51,000 |
167,323 |
66.9389 |
0.01976704 |
270.65 |
-0.0028 |
-0.00085344 |
| 6 |
71,000 |
232,940 |
3.95642 |
0.00116833 |
214.65 |
-0.002 |
-0.0006096 |
See also
References
- U.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).
- ^ Geometric altitude vs. temperature, pressure, density, and the speed of sound derived from the 1962 U.S. Standard Atmosphere.
- ^ 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