Identification and Reduction of Satellite-Induced Signals in GRACE Accelerometer Data

Abstract

Although the GRACE satellite mission has achieved outstanding results in the ten years since it has been launched, signals within accelerometer data remain non-understood. We analyzed 10 Hz Level 1a Accelerometer data (ACC1A) and could link signals to switch events due to magnetic torquers and heaters, and also were able to find a systematic for so called “twangs”. Those signals could be either empirically or physically modelled. With those signals time-series consisting of spikes only could be computed, with which a possible impact onto the gravity field could be determined. It showed that especially the radial component could have an impact. In order to investigate the impact onto the gravity field sufficiently we subtracted the modelled signals from ACC1A, downsampled that data to 1 Hz in order to obtain ACC1B data format and derived a gravity field with the use of our ACC1B dataset. The results appear to have a little, but visible effect of up to 2 cm equivalent water height onto the gravity field determined by GRACE.