# Hypsometric equation

From AMS Glossary

## hypsometric equation

An equation relating the thickness,

*h*, between two isobaric surfaces to the mean virtual temperature of the layer: where*z*_{1}and*z*_{2}are geometric heights at pressure levels*p*_{1}and*p*_{2}, respectively;*R*is the gas constant for dry air; is the mean virtual temperature of the layer; and_{d}*g*is gravity.The hypsometric equation is derived from the hydrostatic equation and the ideal gas law.

**Reference:**

Wallace, J. M., and P. V. Hobbs, 1977: *Atmospheric Science: An Introductory Survey*. Academic Press, 55–57.

*term edited 9 December 2015*