The diurnal variations of the electron density Ne (a) and the rate of change density index in 10 s (RODI) (b) in the equatorial region for the NH (top) and SH (bottom) during HSA (left) and LSA (right). Additional bars to the right present the cumulative distribution of the results at a given value. The bars above the distribution show the statistics of the measurements at a given MLT. The color bar shows the density of counts, and it is the same scale for all plots. The Y-axis limit corresponds to the X-axis limits of each region in Figure 2.