Re: Barometric Pressure vs Altitude

[Bob Giansiracusa <bobgian@radonc.washington.edu>]

> Date: Wed, 30 Jun 1999 13:21:33 -0500 (CDT)
> From: Bob Giansiracusa <bobgian@radonc.washington.edu>
>
> I believe barometric pressure is a negative exponential function of distance
> from center of earth.  Ie:
> 
>                                               exp ( - altitude )
>    Pressure = (Pressure at sea level) *  ------------------------------
>                                            exp ( - alt-at-sea-level )
> 
> where "exp" is e to the power ( ... )
> and "altitude" and "alt-at-sea-level" are the distances to the point in
> question and to sea level from the center of the earth.
> 
> Bob

Stupid mistake.  The pressure drops to half of sea-level value at 18,000 feet.
Thus my normalization factor above is wrong.  Should be something like:

                                                                
  Pressure at H above sealevel = (Pressure at sealevel) * 2 ^ ( - H/18000 )

where 2 ^ x is two to the power x.

Sorry.
 Bob
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