Estimation of geoid and sea surface topography from satellite altimetry by the adjoint method

In the North Atlantic fully reprocessed ERS-1 altimeter data of the year
1.993 are analysed in a simultaneous estimation of the geoid undulations and the sea
surface topography. The estimation is based on an assimilation of so-called sea
surface heights maps into a dynamic model by the adjoint method. The preliminary
result for the geoid of the North Atlantic corresponds remarkably well with the geoid
of the EGM96 gravity model.