Extending the Global Mass Change Data Record: GRACE Follow‐On Instrument and Science Data Performance

TLDR

Since June 2018, the GRACE‑FO mission extends the 15‑year monthly mass change record of GRACE, which ended in June 2017. GRACE‑FO’s instrument and flight system outperform GRACE, delivering equivalent precision over June 2018–Dec 2019, detecting large interannual terrestrial water variations that match independent estimates, and successfully demonstrating satellite‑to‑satellite laser ranging interferometry, while one accelerometer requires extra calibration.

Abstract

Abstract Since June, 2018, the Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO) is extending the 15‐year monthly mass change record of the GRACE mission, which ended in June 2017. The GRACE‐FO instrument and flight system performance has improved over GRACE. Better attitude solutions and enhanced pointing performance result in reduced fuel consumption and gravity range rate post‐fit residuals. One accelerometer requires additional calibrations due to unexpected measurement noise. The GRACE‐FO gravity and mass change fields from June 2018 through December 2019 continue the GRACE record at an equivalent precision and spatiotemporal sampling. During this period, GRACE‐FO observed large interannual terrestrial water variations associated with excess rainfall (Central US, Middle East), drought (Europe, Australia), and ice melt (Greenland). These observations are consistent with independent mass change estimates, providing high confidence that no intermission biases exist from GRACE to GRACE‐FO, despite the 11‐month gap. GRACE‐FO has also successfully demonstrated satellite‐to‐satellite laser ranging interferometry.