How to determine gravity anomalies from geoid surface?

[nasrol]

What is the formula to calculate gravity anomalies from the geoid surface?

or

How to convert geoid into gravity anomalies?

 

[IRstuff]

Duh?? Why are they related? The geoid is a idealized approximation to the surface of the Earth. Gravity anomalies are, by definition, nonideal.

TTFN

FAQ731-376
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[nasrol]

nowadays, there are many geoid surface model derived from gravity anomalies. I just want to know the exact formula for this derivation.