Review of the Post-processing Methods on GRACE Time Varied Gravity Data

The gravity field is a physical parameter reflecting the density change and dynamic characteristics of the earth under different circumstances including the solid earth tide, internal heat flow, mass exchange of solids and liquids, surface loads, and seismic tectonic movements. The time varied global gravity model has been provided by GRACE since 2002, but with the existing system error in GRACE and the need for focusing on local areas, post-processing is required when using GRACE products. In last decade, many algorithms have been shown to be effective. The ideas for these algorithms are reviewed in this article; a Gaussian filter with isotropic and non-isotropic types, the destriping filter, the empirical orthogonal functions method, wavelet analysis, and the Slepian function method. The future directions in post-processing algorithms are also discussed.