On mars the atmosphere is mainly co_2. the temperature is 220 k. and the acceleration of gravity is 3.7 m s^-2. what is the scale height of the martian atmosphere? compare to the scale height of the earth's atmosphere. many species in the atmosphere have mass concentrations that decrease roughly exponentially with altitude: rho(z) = rho(0) exp (- z/h) where h is a species-dependent scale height. if rho (z) is horizontally uniform, show that the total atmospheric mass m of such a species is given by m = a rho (0) h where a is the surface area of the earth. equation (2) allows a quick estimate of the total atmospheric mass of a species simply from knowing its scale height and its concentration in surface air. let us first apply it to air itself. 2.1 calculate the mass density of air at the surface of the earth using the ideal gas law and assuming global average values of surface pressure (984 hpa) and temperature (288 k). 2.2 infer the mass of the atmosphere using equation (2). compare to the value given in chapter 2. explain the difference.