Geoidal geopotential and World Height System

The geoidal geopotential value of W-0 = 62 636 856.0 +/- 0.5m(2)s(-2), determined from the 1993-1998 TOPEX/POSEIDON altimeter data, can be used to practically define and realize the World Height System. The W-0-value can also uniquely define the geoidal surface and is required for a number of applications, including General Relativity in precise time keeping and time definitions. Furthermore, the W-0-value provides a scale parameter for the Earth that is independent of the tidal references system. All of the above qualities make the geoidal potential W-0 ideally suited for official adoption as one of the fundamental constants, replacing the currently adopted semi-major axis a of the mean Earth ellipsoid. Vertical shifts of the Local Vertical Datum (LVD) origins call easily be determined with respect to the World Height System (defined by W-0), in using the recent EGM96 gravity model and ellipsoidal height observations (e.g. GPS) at levelling points. Using this methodology the LVD vertical displacements Sor the NAVD88 (North American Vertical Datum 88), NAP (Normal Amsterdams Peil), AHD Australian Height Datum), KHD (Kronstadt Height Datum), and N60 (Finnish Height Datum) were determined with respect to the proposed World Height System as follows: -55.1 cm, -11.0 cm, +42.4 cm, -11.1 cm and +1.8 cm, respectively.