Anomalous potential modelling in Brazilian Vertical Datum aiming at its new definition

• Autor(a) principal: Correia de Freitas, Sílvio Rogério
• Data de Publicação: 2007
• Outros Autores: Ferreira, Vagner Gonçalves, Palmeiro, Alessandra Svorka, Dalazoana, Regiane, Luz, Roberto Teixeira, Faggion, Pedro Luiz
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Boletim de Ciências Geodésicas
• Texto Completo: https://revistas.ufpr.br/bcg/article/view/10737
• topic: Datum Vertical Brasileiro (DVB); Potencial Perturbador (T); Diferença de Potencial; The Brazilian Vertical Datum (BVD); Disturbing Potential T; The Potential Difference

The Brazilian Vertical Datum (BVD) was established by the mean sea level (MSL)from tide gauge observations. However, in this MSL local effects linked to the shiftbetween the MSL from a equipotential surface W0 best fitted to the global MSLwere not taken into account. The relationship between the BVD and W0 can bedetermined by its gravity potential Wi. The potential difference ∆W = Wi – W0 isrelated to the topography of the mean sea level (better known in English as seasurface topography, SSTop) in the datum region by SSTop = ∆W/γ, where γ is thenormal gravity in the considered point. However, the computation of the potentialdifference ∆W is strongly affected by the local components of the DisturbingPotential T not predicted in global geopotential models. The determination of theselocal components is part of the Geodetic Boundary Value Problem – GBVP. In theclassical approach, the solution of GBVP is based on the use of gravity anomalies inthe computations by Stokes’ integral formula, which depends on the local verticalreference frame. The alternative presented here is based in the solution of the GBVPby using gravity disturbances in the context of Molodenskii’s solution associated with the known Earth surface.