Abstract. The
geomagnetic field in the Brazilian sector is influenced by the South American
Magnetic Anomaly (SAMA) that causes a decrease in the magnitude of the local
geomagnetic field when compared to other regions in the world. Thus, the
magnetometer network and data set of space weather over Brazil led by Embrace
are important tools for promoting the understanding of geomagnetic fields
over Brazil. In this sense, in this work we used the H component of
geomagnetic fields obtained at different sites in South America in order to
compare results from the phase coherence obtained from wavelet transform
(WT). Results from comparison between Cachoeira Paulista (CXP) and
Eusébio (EUS), and Cachoeira Paulista and São Luis (SLZ), indicated
that there exist some phenomena that occur simultaneously in both locations,
putting them in the same phase coherence. However, there are other phenomena
putting both locations in a strong phase difference as observed between CXP
and Rio Grande, Argentina (RGA). This study was done for a specific moderate
geomagnetic storm that occurred in March 2003. The results are explained in
terms of nonlinear interaction between physical phenomena acting in distinct
geographic locations and at different times and scales. Keywords. Geomagnetism and paleomagnetism (time variations – diurnal to secular)
Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America