Since 2003 the "International Centre for Global Earth Models" (ICGEM) is established as an IAG service under the roof of the International Gravity Field Service (IGFS). The major task of ICGEM is to make all global gravity field models of the Earth, which are provided as sets of spherical harmonic coefficients, available to the public. This covers the most recent models back to historical data. The spherical harmonic coefficients are available in a standardised self-explanatory format.
The models can not only be downloaded from the ICGEM website but also be used within an interactive visualisation tool and in a dedicated gravity function calculation service. The visualisation service shows the models (or the difference of two models) in terms of quasigeoid heights or gravity anomalies as illuminated projection on a freely rotatable sphere. Additionally, an animation over time of the monthly solutions from GRACE is included. Finally, the calculation service provides the possibility to compute different functionals of the gravity field, such as gravity anomalies, geoid undulations or equivalent water heights on grids of the users’ choice.
In particular, thanks to the availability of the monthly model series from GRACE, the static models from the GOCE mission, and the combined models of high spatial resolution, the importance of gravity field functionals for nearly all geosciences is rising permanently. In addition to its use for educational purposes, ICGEM helps researchers from different geoscientific fields to overcome obstacles in using these models and to get acquainted with the mathematical representation of gravity field in terms of spherical harmonic series. In this way ICGEM enables and stimulates the research based on these products.