Fig. 6
From: Electrodynamics of ionospheric weather over low latitudes
a Lomb-scargle normalized periodograms of the zonal winds measured by TIMED-TIDI at 87.5, 90.0, and 92.5 km altitude as a functions of latitude during January 17–31, 2010. The white contour lines mark the 85 % statistical confidence level; b Lomb-scargle periodogram of the IGS TEC values for the selected time interval of January 15–27, 2010 at various magnetic latitudes. The dashed line marks the 20°S magnetic latitude (Liu et al. 2012)