[G02-P] Poster

[G02-P-21] Influence of the atmosphere on the evaluation of the geopotential from global models on the surface of the Earth: implications for the W0 and the realization of the International Height Reference System

^○Jaakko Makinen (Finnish Geospatial Research Institute, National Land Survey, Masala, Finland)

Outside the atmosphere, its potential can with high accuracy be identified with the potential of a surface layer with the same mass, independently of the scale height of the atmosphere. Not so when the potential is evaluated on the surface of the Earth. In a first-order calculation using spherical-symmetric approximation and a scale height of 7.6 km, the potential on the surface is 0.12 percent less than the potential of the surface layer. This corresponds to 1.2 ppb of in the evaluation of the total geopotential on the surface of the Earth, the equivalent of an offset of +8 mm in height. For a more realistic atmospheric model over a realistic Earth the offset is not constant. This has obvious implications for the geopotential value W0, and for geopotential values determined for the purposes of the International Height Reference System. In fact, the question has already been extensively analyzed in the context of geoid determination.