Source: http://en.wikipedia.org/wiki/Barometric_formula#Pressure_equations

The value of subscript *b* ranges from 0 to 6 in accordance with each of seven successive layers of the atmosphere shown in the table below. In these equations, *g*_{0}, *M* and *R*^{*} are each single-valued constants, while *P,* *L,* *T,* and *h* are multivalued constants in accordance with the table below. The values used for *M,* *g*_{0}, and *R*^{*} are in accordance with the U.S. Standard Atmosphere, 1976, and the value for *R*^{*} in particular does not agree with standard values for this constant. The reference value for *P _{b}* for

Subscript b | Height above sea level | Static pressure | Std. temperature (K) | Temperature lapse rate | |||
---|---|---|---|---|---|---|---|

(m) | (ft) | (pascals) | (inHg) | (K/m) | (K/ft) | ||

0 | 0 | 0 | 101325.00 | 29.92126 | 288.15 | -0.0065 | -0.0019812 |

1 | 11,000 | 36,089 | 22632.10 | 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 | 868.02 | 0.2563258 | 228.65 | 0.0028 | 0.00085344 |

4 | 47,000 | 154,199 | 110.91 | 0.0327506 | 270.65 | 0.0 | 0.0 |

5 | 51,000 | 167,323 | 66.94 | 0.01976704 | 270.65 | -0.0028 | -0.00085344 |

6 | 71,000 | 232,940 | 3.96 | 0.00116833 | 214.65 | -0.002 | -0.0006096 |