TITLE: Equation relating the density of atmosphere to elevation
QUESTION:
Could you give me an equation relating the density of the atmosphere of
Mars relative to elevation?

ANSWER from Jeff Plescia on March 31, 1999:
The scale height of the Martian atmosphere is 10.8 km;
the surface pressure is about 610 Pa.  The mean lapse
rate is about 2.5 K / km.  The pressure and temperature
are strongly influenced by the amount of dust in the atmosphere.

For a clear atmospere, the pressure is 1 mbar at ~19.5 km,
0.1 mbar at ~40 km and 0.01 mbar at 59 km.

I suggest you look in the book Mars editted by Kieffer et al
and published by Univ. Arizona Press for details, particularly
Chapter 24 and 26.