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ISIS 2 Topside Sounder Ionograms

ISIS-2 Topside Sounder Ionogram CDFs at NASA's CDAWeb

https://doi.org/10.48322/v11k-e045

2026-02-12 23:08:33Z

These ionograms were digitized from the original ISIS-2 7-track analog telemetry tapes using the facilities of the former Data Evaluation Laboratory at the NASA/GSFC. This data restoration project is headed by Dr. R.F. Benson (NASA/GSFC). Ionograms were digitized at the rate of 40,000 16-bit samples/sec. This sample rate is higher than the Nyquist frequency of 30 kHz. The sample frequency of 40 kHz provides a measurement every 25 microseconds corresponding to an apparent range (c*t/2) interval of 3.75 km. Ionograms with this sample rate are designated as "full" ionograms because they have the full 3.75 km apparent-range resolution. The ionograms used for most analysis, and those available from CDAWeb, were produced by averaging every four samples of the sounder-receiver video amplitude output to yield an average value every 100 microseconds corresponding to an apparent-range resolution of 15 km. These ionogram files are referred to as "average" files with standard resolution. Each ionogram consists of a fixed-frequency and and a swept-frequency portion. The time resolution between ionograms is typically 14 or 22 seconds depending on the frequency sweep range.

Users please acknowledge the Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center, ISIS-2 SFS instrument Principal Investigator J. H. Whitteker and ISIS Data-Restoration project lead Robert F. Benson.

spase://VWO/NumericalData/ISIS2/SFS/ISIS2_Ionogram_CDF_PT22S

spase://VWO/NumericalData/ISIS2/SFS/Ionogram.PT22S

spase://VSPO/NumericalData/ISIS2/SFS/Ionogram/PT22S

Online

Open

CDF

None

Please acknowledge the CDAWeb team at NASA/GSFC/SPDF

ISIS-2 Topside Sounder Average Ionogram over Ahmedabad, India: AME, Latitude 23, Longitude 73

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-02-03 04:00:26Z

1978-01-23 07:28:43Z

ISIS-2 Topside Sounder Average Ionogram over Ascension Island, United Kingdom: ACN, Latitude -8, Longitude 346

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1975-01-09 01:22:59Z

1978-09-28 16:37:11Z

ISIS-2 Topside Sounder Average Ionogram over Brazzavillle, Congo: BRZ, Latitude -4, Longitude 15

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-08-05 16:17:40Z

1975-09-25 16:12:59Z

ISIS-2 Topside Sounder Average Ionogram over Fairbanks, AK: ULA, Latitude 65, Longitude 212

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-12-31 00:00:00Z

1979-07-30 02:17:45Z

ISIS-2 Topside Sounder Average Ionogram over Falkland Island, United Kingdom: SOL, Latitude -52, Longitude 302

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-01-12 16:31:05Z

1972-12-10 00:57:02Z

ISIS-2 Topside Sounder Average Ionogram over Johannesburg, South Africa: BUR, Latitude -26, Longitude 28

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-08-07 15:26:03Z

1976-01-16 19:18:39Z

ISIS-2 Topside Sounder Average Ionogram over Kashima, Japan: KSH, Latitude 36, Longitude 141

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-01-01 00:01:10Z

1984-01-06 14:08:01Z

ISIS-2 Topside Sounder Average Ionogram over Kerguelen Island, France: KER, Latitude -49, Longitude 70

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1977-01-01 00:01:37Z

1984-01-27 18:16:53Z

ISIS-2 Topside Sounder Average Ionogram over Kourou, French Guyana: KRU, Latitude 5, Longitude 307

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-02-06 01:16:08Z

1978-07-23 22:07:30Z

ISIS-2 Topside Sounder Average Ionogram over Kwajalein, Marshall Islands: KWA, Latitude 9, Longitude 168

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1978-01-10 08:46:53Z

1978-11-09 07:38:18Z

ISIS-2 Topside Sounder Average Ionogram over Las Palmas, Canary Island, Spain: CNA, Latitude 28, Longitude 345

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1974-01-16 17:42:39Z

1976-02-01 11:15:40Z

ISIS-2 Topside Sounder Average Ionogram over Lauder, New Zealand: LAU, Latitude -45, Longitude 170

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-01-01 04:14:29Z

1981-01-18 15:47:50Z

ISIS-2 Topside Sounder Average Ionogram over Orroral, Australia: ORR, Latitude -36, Longitude 149

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-03-15 03:33:11Z

1981-07-20 20:42:22Z

ISIS-2 Topside Sounder Average Ionogram over Ottawa, QC, Canada: OTT, Latitude 45, Longitude 284

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1971-11-11 18:18:16Z

1984-01-04 05:16:00Z

ISIS-2 Topside Sounder Average Ionogram over Ouagadougou, Burkina Faso: ODG, Latitude 14, Longitude 359

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1972-08-06 05:36:37Z

1979-11-22 15:25:12Z

ISIS-2 Topside Sounder Average Ionogram over Quito, Equador: QUI, Latitude -1, Longitude 281

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-01-03 02:22:10Z

1979-10-18 04:22:30Z

ISIS-2 Topside Sounder Average Ionogram over Resolute Bay, NU, Canada: RES, Latitude 75, Longitude 265

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1971-04-01 09:22:52Z

1983-01-13 11:06:43Z

ISIS-2 Topside Sounder Average Ionogram over Santiago, Chile: SNT, Latitude -33, Longitude 298

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-06-15 09:48:17Z

1980-03-21 09:09:03Z

ISIS-2 Topside Sounder Average Ionogram over Sodankyla, Finland: SOD, Latitude 67, Longitude 27

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1977-12-11 21:47:50Z

1978-09-13 21:01:48Z

ISIS-2 Topside Sounder Average Ionogram over Syowa Base, Antartica: SYO, Latitude -69, Longitude 40

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-02-03 05:49:37Z

1983-01-13 11:06:43Z

ISIS-2 Topside Sounder Average Ionogram over Terre Adelie, Antarctica: ADL, Latitude -67, Longitude 140

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-01-12 10:18:21Z

1983-02-03 18:47:56Z

ISIS-2 Topside Sounder Average Ionogram over Tromso, Norway: TRO, Latitude 70, Longitude 19

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-01-19 10:38:36Z

1977-10-06 20:20:00Z

ISIS-2 Topside Sounder Average Ionogram over Winkfield, United Kingdom: WNK, Latitude 51, Longitude 359

These Ionograms were digitized from the original ISIS-2 7-Track Analog Telemetry Tapes using the Facilities of the former Data Evaluation Laboratory at the NASA/GSFC.

1973-03-14 11:55:35Z

1979-07-15 04:35:11Z