The EGM96 harmonic model was previously refined to match Egypt better, based on the local gravity data in Egypt, by collocation. The refined model was given the name EGM96EGR. In the current study, the EGM96EGR model was compared with the EGM96 model, regarding the relevant harmonic coefficients as well as the associated error estimates. In addition, the two models were compared in terms of the relevant computed low degree geoidal heights, gravity anomalies and deflection components in the Egyptian territory. The comparison showed very significant differences between the two models. Again they were compared in two far test areas, one with and the other without data contribution to the EGM96 model. The discrepancy between the two models in both areas was found to be insignificant. A global spectral analysis was performed, involving the power spectra (degree variances) and error spectra, based on the coefficients and standard errors pertaining to both the refined and original model. Small differences were detected between the two models regarding the power spectra. However, the error degree variances (error spectra) of the refined model were greater than those of the original one. |
