spase://NASA/NumericalData/SESAME/KeyParameters/AIS/PT900S

This set of key parameters from the SESAME (Satellite Experiments Simultaneous with Antartic MEasurements) ground-based experiment contains ionospheric parameters that are derived from quarter-hourly ionograms. The three parameters include the lowest plasma frequency recorded and the highest plasma frequency recorded from the E-region (MHz), and the highest plasma frequency recorded from the F-region (MHz). Please see references: (1) Grubb, RN, The NOAA SEL HF Radar system (ionospheric sounder) NOAA Tech Memo ERL SEL-55, Space Environ Lab, Boulder, CO, 1979, (2) Jarvis,MJ and Dudeney ,JR Reduction of ambiguities in HF radar results through a revised receiving array and sounding pattern. Radio Sci 21, 151-158, 1986, and (3) Dudeney, J. R. et. al., Satellite Experiments Simultaneous with Antarctic Measurements (SESAME), Space Science Reviews, Volume 71, Issue 1-4, pp. 705-742, 1995.