Scale Height -- from Eric Weisstein's World of Physics

Fluid Mechanics "> Buoyancy and Hydrostatics v

Scale Height

An e-folding distance, most commonly used to describe the falloff in atmospheric pressure or other related quantities. For atmospheres, the pressure and density scale heights are given by

respectively, where R is the universal gas constant, T is the temperature, is the molecular mass, g is the gravitational acceleration, k is Boltzmann's constant, and m is the molecular mass.

Density Scale Height, Pressure Scale Height