Adiabatic temperature gradient

From Glossary of Meteorology

adiabatic temperature gradient

The rate of change of temperature due to pressure under adiabatic conditions.

In practice, since in the sea the pressure changes can be considered proportional to depth changes, the adiabatic temperature gradient is usually given as rate of change per unit depth, instead of per unit pressure. For practical purposes, the unit of depth is often chosen as 1000 m.