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Determination of Potential coefficients to degree 52 from 5° Mean Gravity Anomalies
Abstract A set of 38406 1°×1° mean free air anomalies were used to derive a set of 1507 5° equal area anomalies that were supplemented by 147 predicted anomalies to form a global coverage of 1654 anomalies. These anomalies were used to derive potential coefficients to degree 52 using the summation formulae. In these computations, a smoothing operator was introduced and found to significantly effect the results at higher degrees. In addition, the effects of the atmosphere, spherical approximation and terrain were studied. It was found that the atmospheric effects and spherical approximation effects were about 0.3% of the actual coefficients. The terrain correction effects amounted to 10 to 25% of the low degree coefficients depending on a specific terrain correction model chosen; however, the correction terms found from the models did not yield solutions that agreed better with current satellite derived potential coefficient determinations. Anomalies were computed from the derived potential coefficients for comparison to the original anomalies. These comparisons showed that the agreement between the two anomalies became significantly better as the degree of expansion increased to the maximum considered. These comparisons shed some doubt on the rule of thumb that a block of size $ θ^{°} $ can be represented by a spherical harmonic expansion to $ 180^{°} $/$ θ^{°} $.
Determination of Potential coefficients to degree 52 from 5° Mean Gravity Anomalies
Abstract A set of 38406 1°×1° mean free air anomalies were used to derive a set of 1507 5° equal area anomalies that were supplemented by 147 predicted anomalies to form a global coverage of 1654 anomalies. These anomalies were used to derive potential coefficients to degree 52 using the summation formulae. In these computations, a smoothing operator was introduced and found to significantly effect the results at higher degrees. In addition, the effects of the atmosphere, spherical approximation and terrain were studied. It was found that the atmospheric effects and spherical approximation effects were about 0.3% of the actual coefficients. The terrain correction effects amounted to 10 to 25% of the low degree coefficients depending on a specific terrain correction model chosen; however, the correction terms found from the models did not yield solutions that agreed better with current satellite derived potential coefficient determinations. Anomalies were computed from the derived potential coefficients for comparison to the original anomalies. These comparisons showed that the agreement between the two anomalies became significantly better as the degree of expansion increased to the maximum considered. These comparisons shed some doubt on the rule of thumb that a block of size $ θ^{°} $ can be represented by a spherical harmonic expansion to $ 180^{°} $/$ θ^{°} $.
Determination of Potential coefficients to degree 52 from 5° Mean Gravity Anomalies
Rapp, R. H. (author)
Bulletin Géodésique ; 51
1977
Article (Journal)
Electronic Resource
English
Determination of Potential coefficients to degree 52 from 5° Mean Gravity Anomalies
| Online Contents | 1977
Comparison of mean gravity anomalies at elevation with corresponding ground anomalies
| Online Contents | 1967