Determination of vertical gradient of gravity anomalies by numerical differentiation method

The article examines a fairly simple method of calculating the vertical gradient of gravity anomalies (VGGA), based on the use of the formula of numerical differentiation of gravity anomalies. The results of comparing the values of VGGA obtained by the method of numerical differentiation of gravity anomalies with the values of the vertical gradient of gravity anomalies calculated by the method of expansion in a series of spherical functions, which uses a set of harmonic coefficients of the global model of geopotential EIGEN-6C4, up to the degree N=2190 have been analysed. It is shown that the standard deviation obtained as a result of comparison of these methods was 0.13 E. Thus, the method of calculating the VGGA based on the use of formulas for numerical differentiation of force anomalies is not inferior in accuracy to the analytical method using the spherical function series expansion, which uses a set of harmonic coefficients of the global geopotential model EIGEN-6C4, up to degree N=2190.