7 Romay-Merino, Dow, Pfriz, and Boomkamp are engaged in mapping global ocean tides and dynamic sea surface topography. They have computed a multi-arc tidal solution including more than 500 tidal spherical harmonic coefficients. Combining the direct contribution of the tides into the altimeter measurements with the perturbations on the ERS-1 orbit, they have produced accurate tidal maps of the main lunar diurnal and semidiurnal tidal components in the open oceans. The sea surface topography, defined as the difference between the sea surface and the geoid and after corrections for tidal effects, has been modelled and compared to tide gauge measurements over the Pacific.
Agreement is at the sub-decimeter level.
Anzenhofer and Gruber have generated sea surface models from ERS-1 altimeter data. They have upgraded radar altimeter data to geophysical data records by the addition of Earth and Ocean Tides with precise corrections for ionospheric and tropospheric path delays from a new ionospheric model and met data. The result is a global 15 minute sea surface height model. Andersen has been working on the difficult problem of separating tidal constituents from altimetry with the current ERS-1 orbit. He has produced preliminary maps of the M2 and K1 tidal amplitudes and phases in a half degree by half degree grid by submitting global repeat tracks to a collinear analysis.