Fig. 2

This figure displays the temporal variation of correlation coefficient, r, in two altitude regions, one encompassing the upper part of the sporadic layer occurring between 96–100 km, while the other represents the 85–90-km region. The top panel displays r between Na and Ne (solid line) and Fe and Ne (dashed line) for the upper portion of the layer. The middle panel is similar to the above except for the 85–90-km region, while the lower panel represents r between neutrals only. The solid/dashed lines display the correlation between Na and Fe for the upper/lower part of the sporadic layers