NASA study refines measurements of Earth's shifting center of mass

A new study published in the Geophysical Journal International has refined the measurement of how Earth's center of mass oscillates annually relative to its geometric center. Researchers from NASA's Jet Propulsion Laboratory utilized a combination of satellite tracking data, GPS, and low-orbit satellites alongside models of water, ocean, and atmospheric distribution to achieve more precise estimates of this seasonal movement.

The oscillation is primarily driven by the annual redistribution of approximately 6.3 trillion tons of water between continents and oceans, which causes an annual global mean sea level fluctuation of about 17.3 millimeters. This mass transfer causes the center of mass—which accounts for the distribution of all Earth system mass, including ice, snow, and the atmosphere—to shift away from the geometric center, which represents the average position of the Earth's surface.

Key factors contributing to these shifts include snow accumulation and water movement in the Amazon region.