Ocean tide measurement by seasat altimeter data

Tides in the deep ocean have been measured directly by satellite altimetry, independent of knowledge of earth tides, ocean loading, tidal dissipation, or ocean bottom topography. Conventional tide predictions for the deep ocean are sensitive to uncertainties in these parameters. Correction of Seasat altimetry for orbit uncertainty, and subsequent harmonic analysis of sub-track crossover differences, provides a simple and direct measure of the ocean tide. Comparison of M2 altimetric tide parameters at 11 locations in the northeast Pacific with those determined from bottom pressure gauges shows fair agreement at 5 locations, but puzzling systematic differences at the other locations. The estimated precision of the altimeter solutions is 8 cm in amplitude and 10 degrees in phase angle.