Gravity Field Variability, the Geoid, and Ocean Dynamics
With the advent of accurate satellite altimetry, physical oceanography and geodesy have come to have many overlapping problems. The most fundamental of these problems concerns the detailed determination of the geoid. This gravitational equipotential of the earth is central to a description of the solid earth, and appears as the principle reference surface for computing oceanic currents. From the oceanographer’s point of view, knowledge of the sea surface elevation relative to the geoid determines the absolute circulation of the ocean. Great progress has occurred in recent years in determining the geoid with much improved accuracy, although much remains to be done for the result to be fully useful for oceanographic purposes. The possibility of measurement of the earth’s time variable gravity field and the very high accuracies and precisions which appear possible, raise a myriad of new and interesting challenges for understanding and using the measurements. This present paper summarizes some of the work we have performed (Condi and Wunsch (2003)) in exploring the idea of measuring bottom pressure changes from space, and how these data might be used, but with particular attention paid to basic concepts in ocean dynamics and errors in model approximations.
KeywordsOcean dynamics geoid bottom pressure
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