  The solar quiet daily variation (Sq) was investigated with respect to the
longitudinal and seasonal variations at the Brazilian geomagnetic ground
stations of Tatuoca (TTB), Vassouras (VSS ) and S\~ao Martinho da Serra (SMS).
The data utilized was collected during the time interval from January to May
2010. We employed the continuous wavelet transforms and cross wavelet coherence
to study the spectral content and correlations of the time series in the
time-frequency domain. We identified possible phenomena of regional or global
scope that could be affecting the magnetic response measured at TTB, VSS and
SMS observatories. As a result some signatures of planetary waves and
semidiurnal tides in the Sq variability were obtained.
