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Scanning High Resolution Infrared Radiometer

NSSDCA ID: 1973-015A-02

Mission Name: Meteor 1-14
Principal Investigator:

Description

The Meteor 1 high-resolution scanning IR radiometer made operational measurements of cloud distribution and snow and ice cover on the dayside and nightside of the earth. The radiometer measured the outgoing radiation from the earth-atmosphere system in the 8- to 12-micron atmospheric window. Measurements made in this spectral region allowed the thermal relief to be constructed and equivalent radiation temperatures of the earth's surface and cloud tops to be determined. The instrument was a narrow-angle scanning radiometer with an instantaneous viewing angle of 1.5 by 1.5 deg. It was mounted in the base of the satellite in a sealed instrument compartment with its optical axis directed toward nadir. The radiometer measured the intensity of the outgoing radiation by comparing the earth's radiation flux with the radiation flux from space. Each type of radiation entered the radiometer through separate windows, which were oriented in mutually perpendicular directions. The radiation from the earth-atmosphere system fell on a plane scanning mirror that was mounted at an angle of 45 deg to the satellite velocity vector and scanned about an axis parallel to the velocity vector, through an angle of plus or minus 50 deg from nadir. The radiation was reflected from the scanning mirror through a stationary modulating disk and filter window onto a parabolic mirror, which focused the parallel beam through a movable modulating disk onto a thermistor bolometer. The stationary and movable modulating disks sampled both emitted and space radiation, the latter serving as a calibration check. The bolometer converted the radiant flux into variable electric voltages (0 to 6 v) whose frequency was equal to the modulator frequency and whose magnitudes were proportional to the differences in the radiant flux intensities between earth and space developed at the bolometer output. During the movement of the scanning mirror through the plus or minus 40-deg sector, line scanning (40 lines per minute) of the target area was accomplished in a plane normal to the orbital plane using a forward and back path, while scanning along the flight path was provided by the relative motion of the satellite with respect to the earth. With the indicated viewing and scanning angles from the satellite's orbital altitude, the radiometer recorded in each scan the mean radiation intensities from a band about 1100 km wide with a resolution of about 15 km at nadir to about 24 to 27 km at the edges. The radiometer was capable of measuring radiation temperatures within 0.5 to 0.6 deg for temperatures of 293 to 298 deg k and 1.5 to 2 deg for temperatures around 223 deg k. The video signals were amplified and sent either to the satellite memory unit for later transmission or to the radio telemetry unit for direct transmission to earth depending on whether the satellite was beyond or within the zone of radio communication with a ground receiving station, respectively. The ground receivers recorded the transmitted data in digital form on magnetic tape and subsequently by computer mapping of brightness termperatures in shades of gray, depicted on 80-mm photographic film. The data on magnetic tape were processed by computers at the Hydrometeorological Center and were used to produce a digital map of the equivalent radiation temperature field with a superposed geographic grid. The photographic film was developed and processed into an IR picture also with a superposed grid. The pictures were archived at the Hydrometeorological Center.

Alternate Names

  • HRIR
  • Meteor1-14/HRIR

Funding Agency

  • Soviet Hydrometeorological Service (U.S.S.R)

Discipline

  • Earth Science: Atmospheric Dynamics

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office

 

Personnel

NameRoleOriginal AffiliationE-mail
Principal InvestigatorSoviet Hydrometeorological Service
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