Improving the determination of the gravity rate of change by combining superconducting with absolute gravimeter data

This paper evaluates different data-processing methods to determine the gravity rate of change, using repeated absolute gravimeter (AG) measurements and continuous monitoring by a superconducting gravimeter (SG). Based on synthetic data representative of signals observed by SGs at various station locations, we demonstrate that the addition of SG information mitigates the error in the estimation of gravity rates of change caused by the presence of long period, interannual, and annual signals in the AG data. These results are discussed as a function of the sampling rate of the absolute gravity measurements, the duration of the observations, and the uncertainties of the AGs.

► We propose and test 5 methods to process gravimeter data to retrieve a trend. ► The best method combines superconducting (SG) and absolute gravimeter (AG) data. ► The result is only affected by the AG setup noise, and not by any climatic signal. ► Unexpectedly, global inversion of AG and SG is not optimal in retrieving the trend. ► This is tested for typical environmental effects on gravity measurements.