GGFC Special Bureau for the Oceans (SBO)

The Global Geophysical Fluids Centre (GGFC) is a product centre of the International Earth Rotation and Reference Systems Service (IERS). Together with its Special Bureaus for the Atmosphere, Oceans, and Hydrosphere, GGFC provides numerical model-based information related to Earth orientation changes, surface deformations, gravity field variations, and geocenter motion that are caused by mass transports in the Earth's fluid envelope.

Large-scale mass re-distributions in the world's oceans have a major impact on the orientation of the solid Earth with respect to inertial space. Changes in oceanic currents and ocean-bottom pressure have been shown to be a major source of polar motion excitation and also measurably change the length of day. Globally integrated estimates of oceanic angular momentum are provided by unconstrained ocean model experiments and global ocean synthesis that assimilate elements of the ocean observing system.

The Special Bureau for the Oceans (SBO) has been established in 1998 to support the international scientific community in collecting, analyzing, archiving, and distributing data of ocean mass transports and mass variability that is affecting the orientation of the Earth. After having been led by Richard Gross (JPL) for more than 20 years, the SBO was transferred to GFZ in January 2021.

Available Data Sets

Non-Tidal Ocean Angular Momentum (OAM)

Non-Tidal Ocean Excitation Functions (CHI)

Non-Tidal Ocean Contributions to Geocenter Variations (COM)

The GGFC SBO welcomes new submissions in any of data categories above. Please contact Henryk Dobslaw.

Members of the GGFC SBO

  • Robert Dill (GFZ)
  • Henryk Dobslaw (GFZ, Chair)
  • Ichiro Fukumori (JPL)
  • Richard Gross (JPL)
  • Rui Ponte (AER)
  • Jan Saynisch-Wagner (GFZ)
  • Michael Schindelegger (Univ. Bonn)
  • Tony Song (JPL)
  • Maik Thomas (GFZ, FUB)


Dr. Henryk Dobslaw
Earth System Modelling