I am trying to find out the pressure at a given altitude but have been disappointed to find the following equation does not work at all: (h = height in meters)
Where
- sea level standard atmospheric pressure p0 = 101325 Pa
- sea level standard temperature T0 = 288.15 K
- Earth-surface gravitational acceleration g = 9.80665 m/s2.
- temperature lapse rate L = 0.0065 K/m
- universal gas constant R = 8.31447 J/(mol·K)
- molar mass of dry air M = 0.0289644 kg/mol
( from Wikipedia )
Upon completion of the equation, which I think spits out Pascal values, they don't match what a pressure would realistically look like at that altitude (comparing the output value to one from Wolfram). Any idea what the issue with this equation is?
EDIT: inaccuracy alone isn't the problem, it's not giving the right values for anything. I saw a value of 101800 or so for an altitude of 800ft, which is completely wrong, and then the output starts turning into negatives around 100,000ft. I do need something to work at that height, perhaps this isn't the equation for me?
Best Answer
Use the Properties Of The U.S. Standard Atmosphere 1976, which is valid to an altitude of 86 km (282,000 feet).