Investigations of conjugate MSTIDS over the Brazilian sector during daytime

This study focuses on the daytime medium-scale traveling ionospheric disturbances (MSTIDs) observed at conjugate hemispheres. It is the first time that the geomagnetical conjugate daytime MSTIDs are observed over the South America sector. To observe the MSTID characteristics, we used detrended total electron content (TEC) derived from Global Navigation Satellite Systems receivers located at Brazilian sector covering the Northern and Southern Hemispheres along the same magnetic meridian. The geographic grid of 1 degrees N to 14 degrees S in latitude and 60 degrees S to 50 degrees S in longitude was selected for this study. The cross-correlation method between two latitudes and longitudes in time was used to observe the propagation of the MSTID waves. The following features are noted: (a) MSTIDs are well developed at both hemispheres; (b) the peak MSTIDs amplitudes vary from one hemisphere to another; hence, we suppose that MSTIDs generated in Southern Hemisphere or Northern Hemisphere mirrored in the conjugate hemisphere; (c) the gravity wave-induced electric fields from one hemisphere map along the field lines and generate the mirrored MSTIDs in the conjugate region. To investigate the hemispheric mapping mechanism, a rough approximation for the integrated field line conductivity ratio of E and F regions is calculated using digisonde E and F region parameters. We noted that during the period of mapping the decrease in E region conductivity results in an increase in total conductivity. This shows that the E region was partially short circuited; hence, electric field generated at F region could map to the conjugate hemisphere during daytime: daytime MSTIDs at conjugate regions; mechanisms responsible for daytime electrified MSTIDs; gravity wave-induced electric field role in daytime MSTIDs.