gravity reduced to a reference elevation while retaining the gravitational contribution of the intervening topographic mass. The local elevation correction is approximately for a spherical reference, with sign chosen to undo the measured decrease with height.
The adjustment for measurement elevation without adding or removing the attraction of intervening terrain. Near sea level a station metres above a datum receives an approximate correction when reduced to that datum.

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The Free-Air Gravity Anomaly (FAGA) is a geophysical measurement that represents the difference between the observed gravity and the gravity value that would be expected at a particular elevation above a reference surface, typically the Earth's mean sea level. This measurement helps to identify variations in the Earth's gravitational field that are not due to changes in elevation, such as those caused by geological structures.