Modernization of

Vassouras and Tatuoca magnetic observatories in


Pinheiro, K. P. (1), Matzka, J. (2), Martins,

C. M. (3), Soares, G. B. (1), Protásio, J. M. (1), Miranda, A. G.

(1), Santos, A. (1), Bernardes, V. S. (1), Rettig, S. (2), Haseloff,

J. (2) and Morschhauser, A. (2).

(1) Geoscience Institute, Universidade Federal do Pará

(UFPA), 66075-110, Belém, Brazil. (2) GFZ German research Centre for

Geosciences, 14473 Potsdam, Germany. (3) Geophysics Department,

Observatório Nacional, 20921-400 Rio de Janeiro, Brazil.


There are two

magnetic observatories in Brazil currently in operation: Vassouras

(VSS) in Rio de Janeiro since 1915 and Tatuoca (TTB) in Pará since

1957. The centennial VSS magnetic observatory is located in Rio de

Janeiro (22.24°S, 43.39°W). Since 1999 it is part of INTERMAGNET

(International Real-time Magnetic Observatory Network), following its

standards of measurement and recording the geomagnetic field. VSS is

located in the South Atlantic Anomaly (SAA) region where we observe

the lowest geomagnetic field intensity at the Earth’s surface. VSS

records the SAA variation of intensity and temporal evolution that are

important for theoretical studies- flow patterns in the Earth’s core

that produces the SAA- and practical studies such as the influence of

this strong radiation region on satellites.


Currently, VSS has two DTU FGE variometers measuring continuously the

Earth’s magnetic field and transmitting data in real time. There are

two internet connections in case one of them fails. The modernization

of VSS started in September 2014 with the installation of the first

FGE and later, in November 2017, a second FGE was installed as a

backup system by the staff of GFZ (German Research Centre for

Geosciences- Germany) and Observatório Nacional (ON-Brazil). The two

institutions collaborate on both the operation of Brazilian magnetic

observatories and on the use of these data for research.


TTB is in operation for more than 60 years at the small Tatuoca

Island, located in the Amazon River, in Belém (PA), Brazil (1.20°S,

48.51°W). Although there is an extensive time series of TTB data, it

was never a member of the INTERMAGNET. The importance of TTB data is

highlighted by the position of Tatuoca near both magnetic and

geographic equator, as well as the proximity to the SAA.


With the aim to include TTB in INTERMAGNET, ON, UFPA (Universidade

Federal do Pará) and GFZ started a cooperation in 2015. To fulfil the

necessary requirements like high quality data, stable baselines,

stable power supply and real-time data provision, a complete

modernization of TTB and training of its staff is in the final stages.

Concerning data acquisition and transmission, a new DTU FGE variometer

(attached to a low-power data acquisition system), a model G fluxgate

on a Zeiss theodolite for absolute measurements and a 3G router for

internet were installed during the first visit to the island in 2015.

To guarantee a stable energy supply, a hybrid power system was

installed in late 2017, which comprises twelve new 265W solar panels

(four for observatory operation and eight for staff’s demand),

twelve new 200 Ah batteries, one new automatically starting generator

and one equipment for remote management of power supply through

internet (Easysolar), aiming to avoid power outages and, hence, data

gaps. The final tasks for the TTB modernization is taking place in

2018, when a GEOMAG-02M variometer is installed as a backup system and

another Easysolar unit will be established for energy management

regarding TTB staff’s use. An INTERMAGNET application is also

planned for 2018.