Instituto Brasileiro de Geografia e Estatística

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RMPG - Geodetic Permanent Tide Gauge Network


One of the actions taken by IBGE to accomplish its institutional mission is establishing a homogeneous set of benchmarks with high precision altitudes all over the national territory. This set of benchmarks is formally named the High Precision Altimetric Network (RAAP) of the Brazilian Geodetic System (SGB).

Presently, most RAAP altitudes refer to the Imbituba Datum, that is, to the mean sea level in Porto de Imbituba (SC) between 1949 and 1957. The small RAAP portion in Amapa could not be referred to the Imbituba Datum, which motivated the use of the mean sea level in Porto de Santana between 1957 and 1958.

The RMPG (Geodetic Permanent Tide Gauge Network) was conceived in 1996 by the Department of Geodesy of IBGE – today Coordination of Geodesy, CGED – with the purpose of determining and monitoring the evolution of the altimetric data of SGB in time and space. Five stations are operating: Macaé (RJ), with conventional observations since November of 1994 and digital observations since July of 2001; Imbituba (SC), since June of 1998 and August of 2001; Salvador (BA), since December of 2002 and October of 2004; Santana (AP), with its digital and conventional sensors intalled in October of 2005; and Fortaleza (CE), with digital observations since April of 2008.

Another tide gauge station will be installed in the North Region, in the port of Belém. The RMPG set of stations will enable the mean sea levels all over the Brazilian coast to be determined and correlated with past observations. In addition, the network will allow for the correlation among all the remaining vertical reference systems, notably those used in Nautical Charts and seaport operations, resulting in great benefits for the RAAP’s users in coastal regions.


Technical Instructions for the Geodetic Control of Tide Gauge Stations