Original Record Source.
View the original record authored by ‘Source Author’ at ‘NOAA Ocean Facts’ via recovered Helion Archive database link:
https://oceanservice.noaa.gov/facts/grav-d.html
What is GRAV-D?

GRAV-D measures and monitors Earth’s gravity field to support the geoid—a model of roughly global mean sea level used to measure precise surface elevations—so that it may serve as the “zero reference surface” for all heights in the nation. Accurate heights are critical to many scientific endeavors, but are particularly important for protecting low-lying coastal ecosystems.
