Determining the Ocean Circulation and Improving the Geoid from Satellite Altimetry

Abstract

The combined problem of determining the ocean circulation and improving the geoid from satellite altimetry is formulated and studied. Minimum variance estimation is used to form optimum estimates of the ocean topography and the geoid. These estimates are a function of the altimeter observations, prior knowledge of the ocean circulation and prior knowledge of the geoid. Particular emphasis is placed on the use of a dynamical ocean model as a source of a priori oceanographic information capable of discriminating between geoid errors and ocean topography. The technique is illustrated in a simulation study of Gulf Stream variability, in which an ocean topography, degraded by noise representing the uncertainty in a gravimetric geoid, is reconstructed by assimilation into an ocean model. At the same time an improved estimate of the geoid is made.