Assessment of high-resolution global gravity field models and their application in Quasi-geoid modelling in Finland

The two high-resolution global gravity field models, EGM2008 and EIGEN-6C, are compared with ground truth in Finland and surrounding areas. Thereafter, the models are used as background models in the calculation of a quasi-geoid model for Finland. The differences between height anomalies calculated from the globalmodels and from two GPSlevelling datasets for Finland show standard deviations between 5 and 7 cm. Comparisons with free-air anomalies show small and homogeneously distributed differences over most of the area. In both comparisons the largest discrepancies are found close to the Russian border east of the 29° longitude line. This is most probably due to lower resolution Russian data used in the global models. When the global models are used as background models in the calculation of a quasi-geoid model for Finland, the problems around the 29° longitude line disappear. Comparison between the final quasi-geoid models and GPS-levelling data show an improvement over earlier models for Finland.