This paper presents the analysis of temporal variations of the geomagnetic field in the municipality of Macaé, Brazil. Current and historical magnetic field from the IGRF (International Geomagnetic Reference Field) and Gufm1 models were used to construct two-dimensional maps from 1590 to 2019. Analysis of the maps revealed that there was a large decrease in total magnetic field magnitude from around 48,000 nT in 1590 to 23,000 nT in 2019, i.e., a decrease of more than 50%. This decrease was interpreted as a direct influence of the east to west displacement of the South Atlantic Magnetic Anomaly (SAMA) in the last centuries.
Cite this paper
Fernandes, L. P. M. , Silva, J. V. J. D. S. E. , Homsi, I. R. , Garcia, P. D. C. , Barroso, G. T. D. O. , Ribeiro, T. R. E. , Oliveira, G. G. D. D. , Branco, V. R. D. O. and Santos, H. S. (2020). Time Variations Analysis of the Geomagnetic Field in the Municipality of Macaé, Brazil. Open Access Library Journal, 7, e6646. doi: http://dx.doi.org/10.4236/oalib.1106646.
Moro, J., Jaskulski, T., Muralikrishna, P., Nardin, C.M. and Schuch, N.J. (2007) Estudos Do Plasma Ionosférico Na Regi？o Da Anomalia Geomagnética Do Atlantico Sul. Relatório Final De Projeto De Iniciação Científica PIBIC/INPE CNPQ/MCT.
Barraclough, D.R. (1974) Spherical Harmonic Analysis of the Geomagnetic Field for Eight Epochs between 1600 and 1910. Geophysical Journal of the Royal Astronomical Society, 36, 497-513. https://doi.org/10.1111/j.1365-246X.1974.tb00611.x
Jackson, A., Jonkers, A.R.T. and Walker, M.R. (2000) Four Centuries of Geomagnetic Secular Variation from Historical Records. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 358, 957-990.
Alken, P., Erwan, T., Beggan, C., Aubert, J., Baerenzung, J., Brown, W., Califf, S., Chulliat, A., Cox, G.A., Finlay, C., Fournier, A., Gillet, N., Hammer, M., Holschneider, M., Hulot, G., Korte, M., Lesur, V., Livermore, P., Lowes, F. and Wardinski, I. (2020) Evaluation of Candidate Models for the 13th Generation International Geomagnetic Reference Field. 30 p.
Hartmann, G.A. (2010) Archaeomagnetism in Brazil: Variations in the Intensity of the Terrestrial Magnetic Field in the Last Five Centuries. University of São Paulo, Institute of Astronomy, Geophysics and Atmospheric Sciences, São Paulo.
Menezes, I.R.S., Figueiredo, J.M., Velloso, D.A.F., da Silva Bento, M.E., de Azevedo Lima, I. and Santos, H.S. (2019) Geomagnetic Mapping of the Macaé Region, Brazil. Open Access Library Journal, 6, e5593.