Estimation of GRACE-like geopotential models

The availability of time-dependent global gravity field models like EIGEN-6C or EIGEN-6C2 allows the generation of GRACE-like geopotential Earth models. The paper introduces an approach to generate those GRACE-like models using time-dependent global gravity field models. Such GRACE-like models can then be used to estimate, for example, the Terrestrial Water Storage (TWS) for the months where GRACE data are not available. The paper gives the necessary derivation of such GRACE-like models from the time-dependent global gravity field models. GRACE-like models, created by using the time-dependent global gravity field models at the same months where GRACE data are available, are compared to the original GRACE models. The results proved that the GRACE-like models give comparable values to the original GRACE models and no loss of spectrum power occurs.