The height of a given point in the atmosphere in units proportional to the potential energy of unit mass (geopotential) at this height, relative to sea level. In the CGS system, the relation between the geopotential height H and the geometric height Z is where g is the acceleration of gravity, so that the two heights are numerically interchangeable for most meteorological purposes. Also, 1 geopotential metre is equal to 0. 98 dynamic meter. At present, by convention of the World Meteorological Organization, the geopotential height unit is used for all aerological reports.