Observed changes in the Earth’s dynamic oblateness from GRACE data and geophysical models

A new methodology is proposed to estimate changes in the Earth’s dynamic oblateness (?J2 or equivalently, ?5??C20) on a monthly basis. The algorithm uses monthly Gravity Recovery and Climate Experiment (GRACE) gravity solutions, an ocean bottom pressure model and a glacial isostatic adjustment (GIA) model. The resulting time series agree...