TIROS-4 Medium-Resolution Scanning Radiometer Level 1 Final Meteorological Radiation Data (FMRT) product contains radiances expressed in five infrared/visible wavelength regions, expressed in either equivalent blackbody temperature (IR channels 1 and 2) or effective radiant emmitance (visible channels 3 and 5). The data will trace an elliptical, parabolic, or hyperbolic pattern on the ground due to the rotating of the instrument about the satellite spin axis. There is one orbit per file. The data were originally written on IBM 7094 machines, and these have been recovered from magnetic tapes, referred to as the Final Meteorological Radiation Tapes (FMRT). The data are archived in their original IBM 36-bit word proprietary format, also referred to as a binary TAP file.

The TIROS-4 satellite was successfully launched on February 8, 1962. The Medium-Resolution Scanning Radiometer experiment successfully returned data for about five months, continuing the measurements made by its predecessors flown on TIROS-2, and -3. A follow-on instrument was flown on TIROS-7. Degradation of the instrument after launch results in a departure of the data from the pre-launch calibration. The instrument is a five channel radiometer with a 55 km footprint at nadir with the following characteristics:

Channel 1: 6.0 to 6.5 microns - water vapor absorption
Channel 2: 8.0 to 12.0 microns - atmospheric window
Channel 3: 0.2 to 6.0 microns - reflected solar radiation
Channel 4: unused - transmitted redundant time reference signals
Channel 5: 0.55 to 0.75 microns - response to the TV system

The Principal Investigator for these data was Joseph D. Barksdale from NASA Goddard Space Flight Center. This product was previously available from the NSSDC with the identifier ESAD-00139 (old ID 62-002A-03A).