Consideration of tidal variations in the geocenter on satellite altimeter observations of ocean tides
Event: 2014 Ocean Surface Topography Science Team Meeting
Session: Tides, internal tides and high-frequency processes
Presentation type: Type Oral
Tidal geocenter motion has been previously ignored when developing ocean tide models from satellite altimetry. Accounting for tidal geocenter motion is necessary because the best orbit determinations for altimetric satellites position sea-surface heights relative to the center of mass of the total Earth system, including the ocean tides. But the ocean tides are presumed relative to the Earth's crust, and thus are effectively relative to the center of figure. By accounting for this effect, we find improved agreement between an altimeter-based ocean tide model and bottom pressure recorder observations. The variance of differences between these two observations is reduced by 31% and 43% for the two tidal constituents with the largest contributions to geocenter variations, O1 and K1, respectively. With this accommodation the predicted contribution from altimeter-based ocean tide models to geocenter variations is amplified by 15-22, providing improved agreement with observations, especially for the K1 component.