Combining terrestrial, marine, and satellite gravity data to compute gravity potential values at IHRF stations

Abstract

In 2015, the International Association of Geodesy published a resolution on the International Height Reference System definition. It is defined that the vertical coordinate must be given in geopotential number and that the realization of this system must be done considering gravity values arranged homogeneously around the stations. However, it should be regarded that for the stations that are located on the coast. This fact can cause a loss in accuracy in determining the potential gravity. Until now, the studies consider only global gravity models, coming from satellite gravity missions to complement the data in the oceanic region and not considering high-frequency components of the gravity field measured at the surface. Consequently, this research considered shipboard-measured marine gravity data integrated with global marine gravity model data derived from altimetric satellites (DTU17 and GRAV31.1) to compute the gravity potential for the two coastal stations that are part of the International Height Reference Frame (IHRF) in Brazil, CEFT and IMBT stations. The gravity potential was computed following the standardization determinations for the IHRF, and the results showed that the marine gravity data incorporated into the computation did not contribute to accuracy.