Analysis of the discrepancies between the Brazilian vertical reference frame and GOCE-based geopotential model

Abstract

In this study we estimate the discrepancies between the Brazilian vertical network, realized in the system of normal-orthometric heights, and a global quasi-geoid model. We consider the GNSS-leveling and a global quasi-geoid model derived from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission enhanced by high degree components of the Earth Gravitational Model 2008 (EGM2008). The results indicate that the enhanced geopotential model fits the GNSS-leveling with a root mean square error of 20.2 cm. The estimated bias of − 0:4±0.6 cm (w.r.t. the centroid of the network) implies that any future changes to the geopotential value W0 (62636856.0m2 s-2) should be minor for the Brazilian Height System (BHS). However, since the GNSS-leveling based “height anomalies” refer to the Brazilian Vertical Datum at Imbituba harbor (BVD-I), Southern Brazil, the results of the comparisons may be an indicator of the mean bias of the national leveling network due to the effect of Mean Dynamic Topography (MDT) at the BVD-I.