# Scale height

From AMS Glossary

## scale height

The height within which some parameter, such as pressure or density, decreases by a factor 1/

*e*in an isothermal atmosphere.The term is most often used in an ionospheric context, but is equally applicable to the neutral atmosphere. It is a measure of the effective "thickness" of an atmospheric layer and is expressed mathematically as where

*T*,*m*, and*g*are, respectively, the absolute temperature, the molecular mass, and the acceleration due to gravity;*R** is the universal gas constant; and*k*is Boltzmann's constant.