Post‐processing removal of correlated errors in GRACE data

TLDR

GRACE gravity fields require smoothing to suppress short‑wavelength errors, but reducing the smoothing radius produces north‑south stripes that reveal correlations in the gravity‑field coefficients. The study aims to examine the spectral signature of these correlated errors. The authors develop a filter that removes the correlated errors. Applying the filter to a surface‑mass variability model demonstrates that it preserves the underlying geophysical signals with minimal degradation.

Abstract

Gravity fields produced by the Gravity Recovery and Climate Experiment (GRACE) satellite mission require smoothing to reduce the effects of errors present in short wavelength components. As the smoothing radius decreases, these errors manifest themselves in maps of surface mass variability as long, linear features generally oriented north to south (i.e., stripes). The presence of stripes implies correlations in the gravity field coefficients. Here we examine the spectral signature of these correlated errors, and present a method to remove them. Finally, we apply the filter to a model of surface‐mass variability to show that the filter has relatively little degradation of the underlying geophysical signals we seek to recover.