An Inversion Method to Determine Ocean Surface Currents Using Irregularly Sampled Satellite Altimetry Data

An inversion method is presented that determines mesoscale sea surface currents using satellite altimeter data. The method directly uses geostrophic cross-track velocity components, expands the unknown velocity components with spline functions, and includes weighted constraints for divergence and kinetic energy. The success of this method is measured by the misfit between input and output velocities and depends on the weights of the constraints, the irregular space-time data distribution of the altimeter data, and the nonstationary character of mesoscale oceanic features. Negative effects of the irregular spatial distribution of the altimeter data are overcome by partitioning the larger regions of interest into smaller subareas to make independent inversions. The relatively weak effects of subtrack temporal separations in the presence of slowing evolving fields are addressed by temporal interpolations, which provide the more important benefit of filling in missing data. The procedure is evaluated...