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Modernization of Vassouras and Tatuoca magnetic observatories in Brazil |
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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). |
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(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. |
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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.
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