The Development of the European Gravimetric Geoid Model EGG07

Abstract

The European Gravity and Geoid Project (EGGP) is a project within IAG Commission 2, reporting to Sub-commission 2.4. The main goal of the project is to compute an improved European geoid and quasigeoid model based on new and improved data sets which have become available since the last computation in 1997 (EGG97). The improvements include better global geopotential models from the CHAMP and GRACE missions, better digital elevation models (DEMs) in some regions (e.g., new national DEMs, SRTM3, GTOPO30), updated gravity data sets for selected areas, updated ship and altimetric gravity data, improved procedures for the merging of ship and altimetric data, the use of GPS/levelling data, as well as refined computation techniquesThis contribution describes the progress made during the 4-year term from 2003 to 2007, including the development of a new geoid and quasigeoid model EGG07 for entire Europe. First, the status of the gravity and terrain data sets as well as the development of the EGG07 model by the spectral combination approach is described. Then, the EGG07 and other models are evaluated by independent GPS and levelling data, showing that the use of GRACE geopotential models as well as upgraded gravity and terrain data leads to significant improvements compared to EGG97 (in total by 25 – 65%). The results indicate an accuracy potential of the EGG07 model in the order of 0.03 – 0.05 m at continental scales and 0.01 – 0.02 m over shorter distances up to a few 100 km, provided that high quality and resolution input data are availableKeywordsGeoidQuasigeoidGravity field modellingGPS/levellingEGGPCHAMPGRACE