Introduction
Every year, water on Earth is redistributed by snow accumulation, monsoon rainfall and changes in ocean circulation. These movements are large enough to shift the planet’s center of mass relative to its geometric center by a fraction of an inch.
Measurement approach
NASA scientists rely on the GRACE‑FO satellite duo to detect these tiny variations. The spacecraft sense minute changes in Earth’s gravity field caused by the movement of water masses.
Relevance for satellites
The center of mass is a key reference for calculating satellite orbits and for precise altimetry over land and sea. Even small shifts can affect the accuracy of navigation systems and geodetic measurements.
Outlook
By continuously monitoring these seasonal fluctuations, researchers aim to improve models of Earth’s gravity field and enhance the precision of future satellite missions.