isothermal atmosphere

(Also called exponential atmosphere.) An idealized atmosphere in hydrostatic equilibrium in which the temperature is constant with height and in which, therefore, the pressure decreases exponentially upward.
In such an atmosphere the thickness between any two heights is given by

where R_d is the gas constant for dry air, T_v the virtual temperature (°K), g the acceleration of gravity, and P_A and P_B the pressures at the heights z_A and z_B, respectively. In the isothermal atmosphere there is no finite height at which the pressure vanishes.