The Gravity Recovery and Climate Experiment (GRACE)

The Gravity Recovery and Climate Experiment (GRACE) monitored changes in the Earth’s gravity field between 2002 and 2017, with a follow-on mission (GRACE-FO) launched in 2018. These dual-satellite missions provide direct, monthly observations of mass transport and lead to paradigm shifts in a wide range of fields. It unambiguously showed that the Earth’s glaciers and ice sheets are losing mass at an alarming pace, provided the first space-based, global estimates of groundwater storage, detected the fingerprint of earthquakes, allowed to separate steric and mass-driven changes in global and regional sea-level change, and more. In this chapter, we provide an introduction to the mission and its data, and discuss two applications relevant to geohazard monitoring, flood forecasting, and operational drought monitoring.