20 years of the ICGEM Service and the new developments  

ICGEM is one of the five services coordinated by the International Gravity Field Service (IGFS) of the International Association of Geodesy (IAG). The service has been actively responding to the needs of the scientific community for the last two decades with an archive of static, temporal, and topographic global gravity field models of the Earth in a standardized format with the possibility to assign DOIs. Furthermore, ICGEM provides interactive calculation and visualisation services of gravity field functionals. Maintenance of such a service and development of new “demand-based” tools are of utmost importance to provide state-of-the-art products.In 2016, the ICGEM portal has been renewed to guarantee a smooth transition to future needs. Since then, the last remaining component of the previous ICGEM portal, the G3 Browser, has been upgraded and integrated into the present ICGEM portal. The G3 Browser (http://icgem.gfz-potsdam.de/g3) aims to compute time series of equivalent water height interactively and gives users the opportunity to compare different gravity model time series as well as impacts of corrections (e.g., GIA, C20) or filters. The G3 Browser is complementary to existing services such as GFZ’s GravIS portal which provides ready-to-use products based on GFZ and COST-G solutions with already applied corrections and filters. On the other hand, the ICGEM G3 Browser includes time series from further processing centres and institutions and different filtering options.Recently, ICGEM has included simulated models (http://icgem.gfz-potsdam.de/sl/simulated) in its archive that are relevant to future gravity mission studies. Currently available simulated Level 2a models are from the ESA’s MAGIC simulation studies and they are the first of their kind on the ICGEM Service. Monthly and weekly series of different scenarios have been made available on the relevant pages together with the links to the publications provided by the authors.As demanded by the users, ICGEM plans to include some practical tools in the service, such as comparison of the functionals computed based on two different models and interactive evaluation tools n spatial and spectral domains. Finally, a new project called SAMDAT (Service and Archive for Mass Distribution And mass Transport data) that is funded by the German Research Foundation will be realized during the next three years which aims to expand the ICGEM service based on FAIR (Findable, Accessible, Interoperable, Reusable) data and a sustainable data archive principles.