Figure 7. Longitudinal variability of the altitude of the main ionospheric peak as measured during a radio occultation campaign performed by MGS. The black points are the measured values, with the red line the 25º longitude running mean of the peak altitudes. A wave-3 structure is evident. Figure made from the MGS radio science data dataset MGS-M-RSS-5-EDS-V1.0 (Hinson, 2008) downloaded from the NASA Planetary Data System (PDS).