Análise de feições anômalas do modelo EGM96 na América do Sul utilizando dados da<br>missão GRACE

of the Earth’s gravity field obtained by the EGM96 geopotential model in the brazilian territory, in order to evaluate if these features reveal the reality of the gravity field in the region or if they are result of the imprecision of the models used to elaborated the EGM96 model. To calculate the EGM96 coefficients, several types of data were used, such as satellite altimetry, land gravity observations, and the JGP95E topographic model. The fact that the gravity data in some regions of Brazil were not available when the coefficients of EGM96 were calculated, and that the topographic model over these regions were unavailable in that occasion, led to the possibility that the detected structures of the gravity field in such regions may be generated by the lack of data. These features were investigated by the analysis of the topographic model JGP95E compared with the topographic data obtained of the new highly precise model of SRTM, and the gravity anomaly of the EGM96 in comparison with a recent gravity field model calculated by GRACE mission and land gravity data. This analysis showed that there is no evidence that the investigated features have been originated by the filling up process of the areas where no gravity data was available to calculate the EGM96.