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CoverNewton's Bulletin


Issue n. 4, April 2009 - External Quality Evaluation Reports of EGM08   [pp. 133-143]



Testing EGM2008 in the central Mediterranean area


Riccardo Barzaghi and Daniela Carrion

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Abstract

The last geopotential model EGM2008 has been compared with gravity and GPS/leveling data over the Central Mediterranean area. In this area, the gravity field has sharp variations due to strong topography/bathymetry signals and to relevant geophysical features. More than 300.000 gravity values covering the whole area have been considered in the comparisons. These data were used in the last Italian geoid computation and have been validated for datum consistency and for outliers. Further comparisons have been carried out using GPS/leveling data which are homogeneously distributed over the Italian Peninsula. About 1000 available values have been used in the comparison. The results show that, in this area, EGM2008 fits gravity and GPS/leveling data better than other existing global models. The geopotential model performances have been also compared with those of the last Italian geoid estimate, the ITALGEO05 geoid which has been computed in 2005. The statistics of the residuals with GPS/leveling data show that EGM2008 and ITALGEO05 have comparable accuracies, even though EGM2008 is slightly better.