GGFC Special Bureau for Loading: current status and plans

The Earth’s surface is perpetually being displaced due to temporally varying atmospheric, oceanic and continental water mass surface loads. These non-geodynamic signals are of substantial magnitude that they contribute significantly to the scatter in geodetic observations of crustal motion. In February, 2002, the International Earth Rotation Service (IERS) established a Special Bureau of Loading (SBL) whose primary charge is to provide consistent and valid estimates of surface mass loading effects to the IERS community for the purpose of correcting geodetic time series. Here we outline the primary principles involved in modelling the surface displacements and gravity changes induced by surface mass loading including the basic theory, the Earth model and the surface load data. We then identify a list of operational issues, including product validation, that need to be addressed by the SBL before products can be provided to the community. Finally, we outline areas for future research to further improve the loading estimates. We conclude by formulating a recommendation on the best procedure for including loading corrections into geodetic data. Success of the SBL will depend on our ability to efficiently provide consistent and reliable estimates of surface mass loading effects. It is imperative that we work closely with the existing Global Geophysical Fluids Center (GGFC) Special Bureaus and with the community to as much as possible to verify the products.

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