Effectiveness of empirical orthogonal function used in decorrelation of GRACE time-variable gravity field

Abstract

Empirical orthogonal function (EOF) was used to process the spherical harmonic coefficient (SHC) of 115 Gravity Recovery and Climate Experiment (GRACE) RL05 monthly gravity field models from March 2003 to February 2013 released by CSR (Center for Space Research). We analyzed the effectiveness of EOF in decorrelation of gravity field. Results show that only a small Gaussian smoothing radius was needed by EOF to significantly weaken the north–south stripes compared with the empirical moving-window filtering algorithm. The comparative experiments with a Global Land Data Assimilation System (GLDAS) hydrological model also show that EOF did not much affect the real geophysical signals, and that the removed signals were nearly uncorrelated with the real geophysical signals. As the Gravity Recovery and Climate Experiment (GRACE) missions continue, EOF can be used to significantly remove the correlated errors from monthly gravity fields and reserve rich effective signals.