Evaluation of Recent Global Geopotential Models in Argentina
Recent Earth Geopotential Models (EGMs) represent a great improvement to several applications related to gravity field modeling. These models offer higher accuracy and better resolution of the gravity field.
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Evaluation of Recent Global Geopotential Models in Argentina A. Pereira and M.C. Pacino
Abstract Recent Earth Geopotential Models (EGMs) represent a great improvement to several applications related to gravity field modeling. These models offer higher accuracy and better resolution of the gravity field. In this research, the most recent models’ behavior like EIGENs, EGM2008 as well as the classic EGM96, are analyzed and compared in Argentina, aiming to know which one suits better in the country. This investigation also studies the differences between EGMs and geoid undulation values (calculated with height data from GPS and spirit leveling) and gravity anomalies (obtained from terrestrial gravimetric campaigns). In principle, a great difference is detected with the satellite-only geopotential models. The EGMs that perform better results are those that include satellite altimetry and terrestrial information in their calculation. The comparison between local data and the results of seven global models is shown with the residual statistic.
51.1 1 Introduction The practical use of theories for studying the Earth – built a century ago – was only possible since the advance of satellite technology and computing tools.
A. Pereira () Facultad de Ciencias Exactas, Ingeniería y Agrimensura de la Universidad Nacional de Rosario, Rosario 2000, Argentina-CONICET e-mail: [email protected]
In practical specific applications, having a geoid model allows us to use an algorithm from which ellipsoidal heights can be transformed into orthometric heights. Many countries, including Argentina, are encouraging the investigation and computing of Geoid Models, mainly due to the increasing use of GNSS technology. In addition, a lot of geological and geophysical applications demand the knowledge of the terrestrial gravity field. Basically, this demand is concentrated in engineering, mining and petroleum companies. In the determination of the third coordinate that locates the point in its spatial position with respect to the sea level, the entailment between the geodetic systems and the knowledge of the geoid undulation value is essential. Therefore, the local and regional geoid determination is fundamental when GPS is used in a three dimensional survey. Until the launching of the gravity satellite missions, the Earth gravity field models arose from the combination of different space and ground data that has been collected during the last decades. This data included information obtained from space tracking stations (like SLR, Doris, PRARE, and GPS), conventional terrestrial gravimetry and satellite altimetry over the oceans. The gravity models precision was limited due to the heterogeneity of the quality and origin of the data and the lack of a global coverage with a uniform precision. Recent gravity satellite campaigns represent a great improvement to several gravity field modeling – related applications; moreover, they provide valuable information about our planet’s geodynamic behavior since they offer the temporal variations of
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