Abstract

In this study, the causes and size of discrepancies between various geoid models were investigated. Local geoid models (Turkish Geoid-1991, Turkish GPS/Leveling Geoid, Updated Turkish Geoid-1999, Turkish Geoid-2003, Turkish Hybrid Geoid Model-2009)  and global geoid models (EIGEN-GL04C, EIGEN-GL04S1, EIGEN-5C) were used in Turkey. Thirty different points were selected in Turkey. The geoid heights of the points in different geoid models were calculated. These models were compared in terms of the criteria based on their developments and geoid height differences calculated using these models at the test points. The differences of geoid heights calculated from various models at the points were compared and some discrepancies were observed among the models. The reasons behind these discrepancies were discussed. It is disclosed that TG-99A and EIGEN-5C geoid models are the best fitting to Turkish GPS/Leveling geoid.

Key words: Gravity, Turkish geoids, global geopotential models, GPS/leveling.