Nightside Ionospheric Echoes Identified From MARSIS Ionograms

This data set contains the maximum frequency and apparent altitude of nightside ionospheric echoes manually extracted from MARSIS ionograms. The "nightside ionograms" analyzed in the associated paper are selected from this database according to stricter criteria of solar zenith angles and spacecraft altitudes (see the paper for details). Format: YYYYMMDD, hhmmss.fff, quality_flag, f_p(max) , TD_max, H'_max YYYYMMDD: year, month, and date hhmmss.fff: hour, minute, second, and fractional seconds quality_flag: 0 = ionospheric echoes are present, 1 = ionospheric echoes are absent, 2 = the ionogram is unreadable due to noise f_p(max): the maximum frequency of ionospheric echoes in MHz, from which the peak electron density can be derived TD_max: the time delay of the ionospheric peak in ms H'_max: the apparent altitude of the ionospheric peak in km