Altitude Atmospheric Pressure Variation
Pressure varies smoothly from the Earth's surface to the top of the mesosphere. Although the pressure changes with the weather, NASA has averaged the conditions for all parts of the earth year-round. As altitude increases, atmospheric pressure decreases. One can calculate the atmospheric pressure at a given altitude. Temperature and humidity also affect the atmospheric pressure, and it is necessary to know these to compute an accurate figure. The graph at right was developed for a temperature of 15 °C and a relative humidity of 0%.
Within the troposphere, the following equation (the Barometric formula) relates atmospheric pressure p to altitude h
where the constant parameters are as described below:
| Parameter | Description | Value |
|---|---|---|
| p0 | sea level standard atmospheric pressure | 101325 Pa |
| L | temperature lapse rate | 0.0065 K/m |
| T0 | sea level standard temperature | 298.15 K |
| g | Earth-surface gravitational acceleration | 9.80665 m/s2 |
| M | molar mass of dry air | 0.0289644 kg/mol |
| R | universal gas constant | 8.31447 J/(mol•K) |
Read more about this topic: Atmospheric Pressure
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