Here, the variational assimilation is used to bring the (full) OMCT model results as close as possible to satellite-measured sea-surface height data. Therefore, either insufficiently known parameters or starting conditions/model fields will be changed by the assimilation routine. With the improved OMCT model (and resulting mass redistributions and currents), we expect to calculate a more accurate oceanic angular momentum, thereby getting an improved estimate of the influence of the oceans on Earth’s rotational changes.