CRC Electron Density Profiles from the ISIS 1 and 2 Topside Sounders -------------------------------------------------------------------- Satellite: ISIS 1 ISIS 2 NSSDC-ID: 69-009A-01F 71-024A-01 Size/Byte: 8,396,644 8,599,152 This data set, provided by the Communications Research Centre (CRC) in Ottawa, Canada, consists of electron density profiles for the ionosphere above the F2 maximum (topside ionosphere). The data were computed from the orginal ionograms using Jackson's method (Jackson, Proceedings of the IEEE., p. 960, June 1969). ISIS-1 was launched on 1969-01-30 into an elliptical orbit (500-3500km) with an inclination of 88.4 degrees and ISIS-2 was launched on 1971-04-01 into an circular orbit at 1400 km with an inclination of 88.1 degrees. Both satellites were fully instrumented ionospheric observatories including sweep- and fixed-frequequency ionosondes, a VLF receiver, energetic and soft particle detectors, an ion mass spectrometer, an electrostatic analyzer, an Langmuir probe, a beacon transmitter, a cosmic noise experiment and ISIS 2 also carried two photometers. A tape recorder with 1-h capacity was included on both satellites. Data were also collected during overflights of several telemetry stations. The telemetry stations were in areas that provided primary data coverage near the 80-deg-W meridian and in areas near Hawaii, Singapore, Australia, the UK, Norway, India, Japan, Antarctica, New Zealand, and Central Africa. Format Description (ASCII): M I5 number of records each record consists of a header and then the electron density profile data HEADER: itype I1 spacecraft identifier iquality I2 quality index* date I6 yddd year and day of year time I6 hhmmss hour minutes and seconds long F6.1 longitude in degrees lat F6.2 latitude in degrees dip F6.2 magnetic inclination (IGRF) L F5.2 L value xhi F6.1 solar zenith angle at 100 km Rz12 I3 12-month-running mean of sunspot number IG12 I3 12-month-running mean of IG index rtec F6.2 TEC found in data set (units?) ln(NmF2) F7.4 IRI value for F2 peak in cm-3 hmF2 F5.1 IRI value for F2 peak height in km TEC_IRI F6.2 IRI value for TEC in TECU n I3 number of data points PROFILE DATA: n height values: 14I5 h/km*10 n density values: 10I7 ln(Ne/cm-3)*100000 starting with the highest value (satellite height). * Quality index ranges from 0 (best) to 10 (worst), actually 4 to 10 for these data sets, with a most likely value of 6. Please acknowledge the NASA Space Physics Data Facility and the instrument's Principal Investigator for data usage. Keywords: ionosphere, topside, sounder, ionogram Data contact: Dieter.Bilitza-1@nasa.gov> NASA Official: Dr. Robert McGuire