An initial investigation of the GOCE error variance-covariance matrices in the context of the GOCE user toolbox project

摘要

The availability of the full error variance-covariance matrices for the GOCE gravity field models is an important feature of the GOCE mission. Potentially, it will allow users to evaluate the accuracy of a geoid or mean dynamic topography (MDT) derived from the gravity field model at any particular location, design optimal filters to remove errors from the surfaces, and rigorously assimilate a geoid/MDT into ocean models, or otherwise combine the GOCE gravity field with other data. Here we present an initial investigation into the error characteristics of the GOCE gravity field models as they are realised in the calculated geoid anomalies. We examine how the error variances depend on location and spatial scale, and how they differ between models. The inhomogeneous and anisotropic nature of the error covariances are explored, and an example of how this information may be used in ocean data assimilation is provided. Finally, we consider some of the practical issues relating to the handling of the huge files containing the error variance-covariance information.