A measure of the altitude of a point or layer in the atmosphere. Technically, it is expressed in terms of the potential energy between the point and sea level, which depends upon the exact acceleration of gravity at that particular location. In practice, it does not differ from the actual altitude by more than a few per cent. It is, however, required for the definition of isobaric surfaces, and thus upper-level charts.
Geopotential height This chart of geopotential height may be compared with those for pressure and thickness for the same area and time.
Subjects: Meteorology and Climatology.