HARMOGRAV. A Spherical Harmonic Function to Represent the Earth's Gravitational Potential

摘要

A new way to estimate a composite earth gravity model, representing 5 deg X 5 deg equal area gravity anomalies, by harmonic coefficients of the earth's gravity potential is demonstrated. This earth gravity model represents a pure terrestrial gravitational potential, developed by conventional mathematical formulas. The observational data used in the development was restricted to mean gravity anomalies derived from surface gravity measurements. The mean gravity anomalies representing the unsurveyed sectors adjacent to surveyed sectors are allowed to take on values which are determined from a previously derived potential function that was developed from all previously established anomaly values and from zero anomaly values for all unestablished sectors. As each new potential function is developed from the already established sector means, that function is used to compute and fix the mean anomaly values for the next step of unsurveyed adjacent sectors. Thus, by successively fixing the means of the adjacent sectors and by always holding to the originally observed sector values, a full set of fixed means and a final potential function can be developed. (Author)