Ionospheric peaked structures and their local time, seasonal, and solar activity dependence based on global ionosphere maps

The total electron content (TEC) data from Global Ionosphere Maps are used to obtain the tidal modes through two-dimensional Fourier transform in both universal time and LT (local time) frames. In the LT frame, a north-south TEC asymmetry is observed along the longitude, where there is a large displacement of the geomagnetic equator from the geographic equator. The phases of tidal modes lead to a constructive or destructive interference of contributing tidal modes, producing different zonal waves and longitudinal peaked structures at different local time