A new European Gravimetric (Quasi)Geoid EGG2015

Abstract

A series of European geoid and quasigeoid models was computed at Institut für Erdmessung (IfE) with support of the International Association of Geodesy (IAG), presently in the form of IAG Sub-Commission 2.4a “Gravity and Geoid in Europe”. The last major re-computation was performed in 2008 and is denoted as EGG2008 (European Gravimetric Geoid 2008). Since that time, several important developments have taken place, including five releases of GOCE global gravity field models, the availability of a number of new gravity field data sets, as well as some improvements in the modeling approach, especially regarding the rigorous linearization of the observation equations with respect to a high-degree reference model.

The present contribution takes the aforementioned refinements into account and discusses the results of corresponding re-computations of the quasigeoid in Europe. The new models are evaluated by different national and European GPS and levelling data sets, where emphasis is put on the effect of the data updates and the modeling refinements. Furthermore, applications of the quasigeoid models are outlined regarding vertical datum connections and the delivery of ground truth data for high-precision optical clock comparisons. The latter topic relates to the presently developed new generation of optical clocks with a projected relative accuracy of 10^{-17} to 10^{-18}, which (according to the laws of general relativity) corresponds to a sensitivity in the gravity potential equivalent 0.1 m to 0.01 m in height, respectively. Once such optical clocks become operational, this would open several interesting applications in geodesy, such as the large-scale control of height systems and gravity field models as well as the interconnection of tide gauges.