International Association of Geodesy

Global Geophysical Fluids Center (GGFC)
Chair: Ben Chao

Directing Board: Ben F. Chao (Chair), David A. Salstein (SBA), Richard S. Gross (SBO), Richard D. Ray (SBT), Clark R. Wilson (SBH), Tim van Hoolst (SBC), Michael M. Watkins (SBG), Tonie van Dam (SBL).

Terms of Reference: In order to take full advantage of the advances in observation and modeling of global mass transport processes and the Earth’s dynamic responses, the International Earth Rotation and Reference Systems Service (IERS), the organization that monitors the rotational motions of the Earth and related properties, created an infrastructure to facilitate the link between the space geodetic measurement and the geodynamic global geophysical fluid research communities. This infrastructure was called the IERS Global Geophysical Fluids Center (GGFC) and is now called a Product Center in the terms of reference of the IERS.
The GGFC builds upon the success of the IERS Sub-Bureau for Atmospheric Angular Momentum (AAM), which was responsible for obtaining AAM and related data products calculated by the world’s major meteorological centers and disseminating them to users concerned with Earth rotation monitoring, prediction, and research. The new GGFC greatly expands these activities to encompass: (1) geodynamic effects – rotation plus gravity and geocenter, because the Earth’s changing gravity and geocenter have obvious impacts on the precise definition of the terrestrial and celestial reference frames that are central to IERS’ measurements; and (2) all geophysical fluids (not just the atmosphere), because they also make important contributions to the geodynamic effects (even though the atmosphere is often the largest contributor on a wide range of timescales). The GGFC is responsible for promoting related science and outreach activities, including collective publications, dedicated symposia and special sessions at professional meetings, and assistance in coordinating and supporting various international projects and observational campaigns. The actual functions of the GGFC reside in its several Special Bureaus (SBs), each of which being responsible for activities related to a certain fluid component or aspect of the Earth system. These components are the atmosphere (SBA), the oceans (SBO), the tides (SBT), hydrology (SBH), mantle (SBM), core (SBC), gravity/geocenter (SBG), and loading (SBL). The primary functions of the SBs are data and information acquisition, archiving, and dissemination; inter-comparison and assessment of data products; recommending conventions and standards; and providing a forum for professional exchanges and discussions. The GGFC supports and provides services to the research community in this new interdisciplinary field. Individual SB Web sites have been developed as the major mechanism for data dissemination and communication.