(Also called equipotential surface, level surface.) A surface of constant geopotential, that is, a surface along which a parcel of air could move without undergoing any changes in its potential energy.
Geopotential surfaces almost coincide with surfaces of constant geometric height. Because of the poleward increase of the acceleration of gravity along a surface of constant geometric height, a given geopotential surface has a smaller geometric height over the poles than over the equator.
See potential, geopotential height, dynamic height.
